Glossary of HVAC Terms
fatmirfati
2,826 views
30 slides
Feb 04, 2015
Slide 1 of 30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
About This Presentation
This glossary is comprised of words and phrases most frequently used in the heating, ventilation and air conditioning HVAC industry. These brief explanations will help your understand of many terms used throughout your work, study and professional career.
Slide Content
!!!!!!!!GLOSSARY OF
HVAC TERMS
!
!!!
10/18/2013 HVAC is term used for heating, ventilation and
air conditioning
!!
This glossary is comprised of words and phrases most frequently used in
the heating, ventilation and air conditioning industry. These brief
explanations will help your understand of many terms used throughout
your work, study and professional career.
HVAC TERMS
!
!!!
10/18/2013 HVAC is term used for heating, ventilation and
air conditioning
!!
This glossary is comprised of words and phrases most frequently used in
the heating, ventilation and air conditioning industry. These brief
explanations will help your understand of many terms used throughout
your work, study and professional career.
Glossary of HVAC terms
Page 1
!
!
!Glossary of HVAC terms
!
HV A C I S T E R M U S E D F O R H E A T I N G , V E N T I L A T I ON A N D AI R
CO N D I T I O N I N G
!!!!Absolute)humidity:)The!weight!of!water!vapour!per!unit!volume;!grains!per!cubic!foot;!or!grams!per!cubic!
meter.!
Absolute)pressure:)The!sum!of!gage!pressure!and!atmospheric!pressure.!Thus,!for!example,!if!the!gage!
pressure!is!154!psi,!the!absolute!pressure!will!be!154+14.7,!or!168.7!psi.!
!
Absolute)zero:)A!temperature!equal!to!–459.6®F!or!–273®C.!At!this!temperature!the!volume!of!an!ideal!gas!
maintained!at!a!constant!pressure!becomes!zero.!
!
Absorption:)The!action!of!a!material!in!extracting!one!or!more!substances!present!in!the!atmosphere!or!a!
mixture!of!gases!or!liquids!accompanied!by!physical!change,!chemical!change,!or!both.!
!
Acceleration:)The!time!rate!of!change!of!velocity.!It!is!the!derivative!of!velocity!with!respect!to!time.!
!!
Accumulator:)A!shell!placed!in!a!suction!line!for!separating!the!liquid!entrained!in!the!suction!gas.!A!storage!
tank!at!the!evaporator!exit!or!suction!line!used!to!prevent!flood!backs!to!the!compressor.!
!!
Acrolein:)A!warning!agent!often!used!with!methyl!chloride!to!call!attention!to!the!escape!of!refrigerant.!The!
material!has!a!compelling,!pungent!odor!and!causes!irritation!of!the!throat!and!eyes.!Acrolein!reacts!with!sulfur!
dioxide!to!form!a!sludge.!
!!
ACR)tube:)A!copper!tube!usually!hard!drawn!and!sold!to!the!trade!cleaned!and!sealed!with!nitrogen!inside!to!
prevent!oxidation.!Identified!by!its!actual!outside!diameter!(OD).!
!!
Activated)alumina:)A!form!of!aluminium!oxide!(Al2O3)!that!absorbs!moisture!readily!and!is!used!as!a!drying!
agent.!
Adiabatic:)Referring!to!a!change!in!gas!conditions!where!no!heat!is!added!or!removed!except!in!the!form!of!
work.!
Adiabatic)process:))Any!thermodynamic!process!taking!place!in!a!closed!system!without!the!addition!or!
Page 1
!
!
!Glossary of HVAC terms
!
HV A C I S T E R M U S E D F O R H E A T I N G , V E N T I L A T I ON A N D AI R
CO N D I T I O N I N G
!!!!Absolute)humidity:)The!weight!of!water!vapour!per!unit!volume;!grains!per!cubic!foot;!or!grams!per!cubic!
meter.!
Absolute)pressure:)The!sum!of!gage!pressure!and!atmospheric!pressure.!Thus,!for!example,!if!the!gage!
pressure!is!154!psi,!the!absolute!pressure!will!be!154+14.7,!or!168.7!psi.!
!
Absolute)zero:)A!temperature!equal!to!–459.6®F!or!–273®C.!At!this!temperature!the!volume!of!an!ideal!gas!
maintained!at!a!constant!pressure!becomes!zero.!
!
Absorption:)The!action!of!a!material!in!extracting!one!or!more!substances!present!in!the!atmosphere!or!a!
mixture!of!gases!or!liquids!accompanied!by!physical!change,!chemical!change,!or!both.!
!
Acceleration:)The!time!rate!of!change!of!velocity.!It!is!the!derivative!of!velocity!with!respect!to!time.!
!!
Accumulator:)A!shell!placed!in!a!suction!line!for!separating!the!liquid!entrained!in!the!suction!gas.!A!storage!
tank!at!the!evaporator!exit!or!suction!line!used!to!prevent!flood!backs!to!the!compressor.!
!!
Acrolein:)A!warning!agent!often!used!with!methyl!chloride!to!call!attention!to!the!escape!of!refrigerant.!The!
material!has!a!compelling,!pungent!odor!and!causes!irritation!of!the!throat!and!eyes.!Acrolein!reacts!with!sulfur!
dioxide!to!form!a!sludge.!
!!
ACR)tube:)A!copper!tube!usually!hard!drawn!and!sold!to!the!trade!cleaned!and!sealed!with!nitrogen!inside!to!
prevent!oxidation.!Identified!by!its!actual!outside!diameter!(OD).!
!!
Activated)alumina:)A!form!of!aluminium!oxide!(Al2O3)!that!absorbs!moisture!readily!and!is!used!as!a!drying!
agent.!
Adiabatic:)Referring!to!a!change!in!gas!conditions!where!no!heat!is!added!or!removed!except!in!the!form!of!
work.!
Adiabatic)process:))Any!thermodynamic!process!taking!place!in!a!closed!system!without!the!addition!or!
Glossary of HVAC terms
Page 2
!
!
!
removal!of!heat.!
!!!
Adsorbent:)A!sorbent!that!changes!physically,!chemically,!or!both!during!the!sorption!process.!
!!!
Aeration:)Exposing!a!substance!or!area!to!air!circulation.!
!!!
Agitation:)A!condition!in!which!a!device!causes!circulation!in!a!tank!containing!fluid.!
!!!
Air,)ambient:)Generally!speaking,!the!air!surrounding!an!object.!
!!!
Air)changes:)A!method!of!expressing!the!amount!of!air!leakage!into!or!out!of!a!building!or!room!in!terms!of!the!
number!of!building!volumes!or!room!volumes!exchanged!per!unit!of!time.!
!!
Air)circulation:)Natural!or!imparted!motion!of!air.!
!!!
Air)cleaner:))A!device!designed!for!the!purpose!of!removing!airborne!impurities!such!as!dust,!gases,!vapors,!
fumes,!and!smoke.!An!air!cleaner!includes!air!washers,!air!filters,!electrostatic!precipitors,!and!charcoal!filters.!
!!
Air)conditioner:)An!assembly!of!equipment!for!the!control!of!at!least!the!first!three!items!enumerated!in!the!
definition!of!air!conditioning.!
!
!
Air)conditioner,)room:)A!factoryXmade!assembly!designed!as!a!unit!for!mounting!in!a!window,!through!a!wall,!
or!as!a!console.!It!is!designed!for!free!delivery!of!conditioned!air!to!an!enclosed!space!without!ducts.!
!!
Air)conditioning:)The!simultaneous!control!of!all,!or!at!least!the!first!three,!of!the!following!factors!affecting!
the!physical!and!chemical!conditions!of!the!atmosphere!within!a!structure—temperature,!humidity,!motion,!
distribution,!dust,!bacteria,!odors,!toxic!gases,!and!ionization—most!of!which!affect!human!health!or!comfort.!
!!
Air<conditioning)system,)central)fan:)A!mechanical!indirect!system!of!heating,!ventilating,!or!air!conditioning!
in!which!the!air!is!treated!or!handled!by!equipment!located!outside!the!rooms!served,!usually!at!a!central!
location!and!conveyed!to!and!from!the!rooms!by!means!of!a!fan!and!a!system!of!distributing!ducts.!
Page 2
!
!
!
removal!of!heat.!
!!!
Adsorbent:)A!sorbent!that!changes!physically,!chemically,!or!both!during!the!sorption!process.!
!!!
Aeration:)Exposing!a!substance!or!area!to!air!circulation.!
!!!
Agitation:)A!condition!in!which!a!device!causes!circulation!in!a!tank!containing!fluid.!
!!!
Air,)ambient:)Generally!speaking,!the!air!surrounding!an!object.!
!!!
Air)changes:)A!method!of!expressing!the!amount!of!air!leakage!into!or!out!of!a!building!or!room!in!terms!of!the!
number!of!building!volumes!or!room!volumes!exchanged!per!unit!of!time.!
!!
Air)circulation:)Natural!or!imparted!motion!of!air.!
!!!
Air)cleaner:))A!device!designed!for!the!purpose!of!removing!airborne!impurities!such!as!dust,!gases,!vapors,!
fumes,!and!smoke.!An!air!cleaner!includes!air!washers,!air!filters,!electrostatic!precipitors,!and!charcoal!filters.!
!!
Air)conditioner:)An!assembly!of!equipment!for!the!control!of!at!least!the!first!three!items!enumerated!in!the!
definition!of!air!conditioning.!
!
!
Air)conditioner,)room:)A!factoryXmade!assembly!designed!as!a!unit!for!mounting!in!a!window,!through!a!wall,!
or!as!a!console.!It!is!designed!for!free!delivery!of!conditioned!air!to!an!enclosed!space!without!ducts.!
!!
Air)conditioning:)The!simultaneous!control!of!all,!or!at!least!the!first!three,!of!the!following!factors!affecting!
the!physical!and!chemical!conditions!of!the!atmosphere!within!a!structure—temperature,!humidity,!motion,!
distribution,!dust,!bacteria,!odors,!toxic!gases,!and!ionization—most!of!which!affect!human!health!or!comfort.!
!!
Air<conditioning)system,)central)fan:)A!mechanical!indirect!system!of!heating,!ventilating,!or!air!conditioning!
in!which!the!air!is!treated!or!handled!by!equipment!located!outside!the!rooms!served,!usually!at!a!central!
location!and!conveyed!to!and!from!the!rooms!by!means!of!a!fan!and!a!system!of!distributing!ducts.!
Glossary of HVAC terms
Page 3
!
!
!
!
Air<conditioning)system,)year)round:)An!airXconditioning!system!that!ventilates,!heats,!and!humidifies!in!
winter,!and!cools!and!dehumidifies!in!summer!to!provide!the!desired!degree!of!air!motion!and!cleanliness.!
!!
Air<conditioning)unit:)A!piece!of!equipment!designed!as!a!specific!airXtreating!combination,!consisting!of!a!
means!for!ventilation,!air!circulation,!air!cleaning,!and!heat!transfer!with!a!control!means!for!maintaining!
temperature!and!humidity!within!prescribed!limits.!
!!
Air)cooler:)A!factoryXassembled!unit!including!elements,!whereby!the!temperature!of!air!passing!through!the!
unit!is!reduced.!
!!
Air)cooler,)spray)type:)A!forcedXcirculation!air!cooler,!wherein!the!coil!surface!capacity!is!augmented!by!a!
liquid!spray!during!the!period!of!operation.!
!
!
Air)cooling:)A!reduction!in!air!temperature!due!to!the!removal!of!heat!as!a!result!of!contact!with!a!medium!
held!at!a!temperature!lower!than!that!of!the!air.!
!!
Air)diffuser:)A!circular,!square,!or!rectangular!air!distribution!outlet,!generally!located!in!the!ceiling,!and!
comprised!of!deflecting!members!discharging!supply!air!in!various!directions!and!planes,!arranged!to!promote!
mixing!of!primary!air!with!secondary!room!air.!
!
!
Air,)dry:)In!psychrometry,!air!unmixed!with!or!containing!no!water!vapor.!
!!!
Air)infiltration:)The!inXleakage!of!air!through!cracks,!crevices,!doors,!windows,!or!other!openings!caused!by!
wind!pressure!or!temperature!difference.!
!!
Air,)recirculated:)Return!air!passed!through!the!conditioner!before!being!again!supplied!to!the!conditioned!
space.!
!!
Air,)return:)Air!returned!from!conditioned!or!refrigerated!space.!
Page 3
!
!
!
!
Air<conditioning)system,)year)round:)An!airXconditioning!system!that!ventilates,!heats,!and!humidifies!in!
winter,!and!cools!and!dehumidifies!in!summer!to!provide!the!desired!degree!of!air!motion!and!cleanliness.!
!!
Air<conditioning)unit:)A!piece!of!equipment!designed!as!a!specific!airXtreating!combination,!consisting!of!a!
means!for!ventilation,!air!circulation,!air!cleaning,!and!heat!transfer!with!a!control!means!for!maintaining!
temperature!and!humidity!within!prescribed!limits.!
!!
Air)cooler:)A!factoryXassembled!unit!including!elements,!whereby!the!temperature!of!air!passing!through!the!
unit!is!reduced.!
!!
Air)cooler,)spray)type:)A!forcedXcirculation!air!cooler,!wherein!the!coil!surface!capacity!is!augmented!by!a!
liquid!spray!during!the!period!of!operation.!
!
!
Air)cooling:)A!reduction!in!air!temperature!due!to!the!removal!of!heat!as!a!result!of!contact!with!a!medium!
held!at!a!temperature!lower!than!that!of!the!air.!
!!
Air)diffuser:)A!circular,!square,!or!rectangular!air!distribution!outlet,!generally!located!in!the!ceiling,!and!
comprised!of!deflecting!members!discharging!supply!air!in!various!directions!and!planes,!arranged!to!promote!
mixing!of!primary!air!with!secondary!room!air.!
!
!
Air,)dry:)In!psychrometry,!air!unmixed!with!or!containing!no!water!vapor.!
!!!
Air)infiltration:)The!inXleakage!of!air!through!cracks,!crevices,!doors,!windows,!or!other!openings!caused!by!
wind!pressure!or!temperature!difference.!
!!
Air,)recirculated:)Return!air!passed!through!the!conditioner!before!being!again!supplied!to!the!conditioned!
space.!
!!
Air,)return:)Air!returned!from!conditioned!or!refrigerated!space.!
Glossary of HVAC terms
Page 4
!
!
!
Air,)saturated:)Moist!air!in!which!the!partial!pressure!of!the!water!vapor!is!equal!to!the!vapor!pressure!of!
water!at!the!existing!temperature.!This!occurs!when!dry!air!and!saturated!water!vapor!coexist!at!the!same!dryX!
bulb!temperature.!
!!
Air,)standard:)Air!with!a!density!of!0.075!lb/ft3!and!an!absolute!viscosity!of!1.22x10!1b!mass/ftXs.!This!is!
substantially!equivalent!to!dry!air!at!70®F!and!29.92!in.!Hg!barometer.!
!!
Air)washer:)An!enclosure!in!which!air!is!forced!through!a!spray!of!water!in!order!to!cleanse,!humidify,!or!
precool!the!air.!
!!
Ambient)temperature:)The!temperature!of!the!medium!surrounding!an!object.!In!a!domestic!system!having!
an!airXcooled!condenser,!it!is!the!temperature!of!the!air!entering!the!condenser.!
!!
Ammonia)machine:)An!abbreviation!for!a!compression!refrigerating!machine!using!ammonia!as!a!refrigerant.!
Similarly,!Freon!machine,!sulfur!dioxide!machine,!and!so!forth.!
!!
Ampere:)Unit!used!to!measure!electrical!current.!It!is!equal!to!1!C!of!electrons!flowing!past!a!point!in!1!s.!A!
coulomb!is!6.28x1018!electrons.!
!!
Analyser:)A!device!used!in!the!high!side!of!an!absorption!system!for!increasing!the!concentration!of!vapor!
entering!the!rectifier!or!condenser.!
!!
Anemometer:)An!instrument!for!measuring!the!velocity!of!air!in!motion.!
!!!
Antifreeze,)liquid:)A!substance!added!to!the!refrigerant!to!prevent!formation!of!ice!crystals!at!the!expansion!
valve.!Antifreeze!agents!in!general!do!not!prevent!corrosion!due!to!moisture.!The!use!of!a!liquid!should!be!a!
temporary!measure!where!large!quantities!of!water!are!involved,!unless!a!drier!is!used!to!reduce!the!moisture!
content.!Ice!crystals!may!form!when!moisture!is!present!below!the!corrosion!limits,!and!in!such!instances,!
suitable!noncorrosive!antifreeze!liquid!is!often!of!value.!Materials!such!as!alcohol!are!corrosive!and,!if!used,!
should!be!allowed!to!remain!in!the!machine!for!a!limited!time!only.!
Page 4
!
!
!
Air,)saturated:)Moist!air!in!which!the!partial!pressure!of!the!water!vapor!is!equal!to!the!vapor!pressure!of!
water!at!the!existing!temperature.!This!occurs!when!dry!air!and!saturated!water!vapor!coexist!at!the!same!dryX!
bulb!temperature.!
!!
Air,)standard:)Air!with!a!density!of!0.075!lb/ft3!and!an!absolute!viscosity!of!1.22x10!1b!mass/ftXs.!This!is!
substantially!equivalent!to!dry!air!at!70®F!and!29.92!in.!Hg!barometer.!
!!
Air)washer:)An!enclosure!in!which!air!is!forced!through!a!spray!of!water!in!order!to!cleanse,!humidify,!or!
precool!the!air.!
!!
Ambient)temperature:)The!temperature!of!the!medium!surrounding!an!object.!In!a!domestic!system!having!
an!airXcooled!condenser,!it!is!the!temperature!of!the!air!entering!the!condenser.!
!!
Ammonia)machine:)An!abbreviation!for!a!compression!refrigerating!machine!using!ammonia!as!a!refrigerant.!
Similarly,!Freon!machine,!sulfur!dioxide!machine,!and!so!forth.!
!!
Ampere:)Unit!used!to!measure!electrical!current.!It!is!equal!to!1!C!of!electrons!flowing!past!a!point!in!1!s.!A!
coulomb!is!6.28x1018!electrons.!
!!
Analyser:)A!device!used!in!the!high!side!of!an!absorption!system!for!increasing!the!concentration!of!vapor!
entering!the!rectifier!or!condenser.!
!!
Anemometer:)An!instrument!for!measuring!the!velocity!of!air!in!motion.!
!!!
Antifreeze,)liquid:)A!substance!added!to!the!refrigerant!to!prevent!formation!of!ice!crystals!at!the!expansion!
valve.!Antifreeze!agents!in!general!do!not!prevent!corrosion!due!to!moisture.!The!use!of!a!liquid!should!be!a!
temporary!measure!where!large!quantities!of!water!are!involved,!unless!a!drier!is!used!to!reduce!the!moisture!
content.!Ice!crystals!may!form!when!moisture!is!present!below!the!corrosion!limits,!and!in!such!instances,!
suitable!noncorrosive!antifreeze!liquid!is!often!of!value.!Materials!such!as!alcohol!are!corrosive!and,!if!used,!
should!be!allowed!to!remain!in!the!machine!for!a!limited!time!only.!
Glossary of HVAC terms
Page 5
!
!
!
Atmospheric)condenser:)A!condenser!operated!with!water!that!is!exposed!to!the!atmosphere.!
!!!
Atmospheric)pressure:)The!pressure!exerted!by!the!atmosphere!in!all!directions!as!indicated!by!a!barometer.!
Standard!atmospheric!pressure!is!considered!to!be!14.695!psi!(pounds!per!square!inch),!which!is!equivalent!to!
29.92!in.!Hg!(inches!of!mercury).!
!!!
Atomize:)To!reduce!to!a!fine!spray.!
!!!
Automatic)air)conditioning:)An!airXconditioning!system!that!regulates!itself!to!maintain!a!definite!set!of!
conditions!by!means!of!automatic!controls!and!valves!usually!responsive!to!temperature!or!pressure.!
!!
Automatic)expansion)valve:)A!pressureXactuated!device!that!regulates!the!flow!of!refrigerant!from!the!liquid!
line!into!the!evaporator!to!maintain!a!constant!evaporator!pressure.!
!Baffle:)A parttti n us dt s durd d u etfl t a r tr a en si
!!!!
Balanced)pressure:)The!same!pressure!in!a!system!or!container!that!exists!outside!the!system!or!container.!
!!
Barometer:)An!instrument!for!measuring!atmospheric!pressure.!
!!
Blast)heater:)A!set!of!heatXdrai ur ct l tr uctti n us dt uad a r d ad srafli tr trcus d rtnu d b a
aii Bleeder:)A p pu tmutmu aaac us dt a ctisui ur dt luus t l ln s ru r uuraid parallul dt d u ma i
etfli Boiler:)A!closed!vessel!in!which!liquid!is!heated!or!vaporised.!
Boiler)horsepower:)T u uln daluid udaptratti t 3i. l t fladur pur tnr rtm ais ad 2 ®F,!which!is!equal!
to!a!heat!output!of!970.3!x34.5!=!33,475!Btu.!
!
Boiling)point:)T u dumpuradnru ad fl c a l ln s daptr us npti d u ass tti t uadt supuisuid ti d u
!
refrigerant!and!the!absolute!pressure!at!the!surface!of!the!liquid!and!vapor.!
!!
Bore:)The!inside!diameter!of!a!cylinder.!
Page 5
!
!
!
Atmospheric)condenser:)A!condenser!operated!with!water!that!is!exposed!to!the!atmosphere.!
!!!
Atmospheric)pressure:)The!pressure!exerted!by!the!atmosphere!in!all!directions!as!indicated!by!a!barometer.!
Standard!atmospheric!pressure!is!considered!to!be!14.695!psi!(pounds!per!square!inch),!which!is!equivalent!to!
29.92!in.!Hg!(inches!of!mercury).!
!!!
Atomize:)To!reduce!to!a!fine!spray.!
!!!
Automatic)air)conditioning:)An!airXconditioning!system!that!regulates!itself!to!maintain!a!definite!set!of!
conditions!by!means!of!automatic!controls!and!valves!usually!responsive!to!temperature!or!pressure.!
!!
Automatic)expansion)valve:)A!pressureXactuated!device!that!regulates!the!flow!of!refrigerant!from!the!liquid!
line!into!the!evaporator!to!maintain!a!constant!evaporator!pressure.!
!Baffle:)A parttti n us dt s durd d u etfl t a r tr a en si
!!!!
Balanced)pressure:)The!same!pressure!in!a!system!or!container!that!exists!outside!the!system!or!container.!
!!
Barometer:)An!instrument!for!measuring!atmospheric!pressure.!
!!
Blast)heater:)A!set!of!heatXdrai ur ct l tr uctti n us dt uad a r d ad srafli tr trcus d rtnu d b a
aii Bleeder:)A p pu tmutmu aaac us dt a ctisui ur dt luus t l ln s ru r uuraid parallul dt d u ma i
etfli Boiler:)A!closed!vessel!in!which!liquid!is!heated!or!vaporised.!
Boiler)horsepower:)T u uln daluid udaptratti t 3i. l t fladur pur tnr rtm ais ad 2 ®F,!which!is!equal!
to!a!heat!output!of!970.3!x34.5!=!33,475!Btu.!
!
Boiling)point:)T u dumpuradnru ad fl c a l ln s daptr us npti d u ass tti t uadt supuisuid ti d u
!
refrigerant!and!the!absolute!pressure!at!the!surface!of!the!liquid!and!vapor.!
!!
Bore:)The!inside!diameter!of!a!cylinder.!
Glossary of HVAC terms
Page 6
!
!
!
Bourdon)tube:)Tn u t ula tc mudal!bent!into!circular!shape!that!is!found!inside!a!pressure!gage.!
!
Brine:)Any!liquid!cooled!by!a!refrigerant!and!used!for!transmission!of!heat!without!a!change!in!its!state!
!!
Brine)system:)A b dum fl uru b r iu cttlus b a ru r uuratiu b dum c rcnladus dhrough!pipes!to!the!
point!wheru d u ru r uuratti iuususi
!
Britis)))serraa)))ui))))B)))))u:)The!amount!of!heat!required!to!raise!the!temperature!of!1!lb!of!water!1F.!It!is!also!the!
measure!of!the!amount!of!heat!removed!in!cooling!1!lb!of!water!1F!and!is!so!used!as!a!measure!of!
ru r uuratiu u
ucdi
!
Butane:)A bsrtcar tit eamma lu ru r uuraid n us dt a l m dus uxduid i mall ni d i
!!Calcium)chloride:)A!chemical!having!the!formula!CaCl2,!which,!in!granular!form,!is!used!as!a!drier.!This!
madur al tln lu i fladurt ais i d u pru uicu t laruu lnaittu t mt dnru mab s tldu ais plnu np d u
drier!unit!or!even!pass!into!the!system!beyond!the!drier.!
!!
Calcium)sulfate:)A!solid!chemical!of!the!formula!CaSO4,!which!may!be!used!as!a!drying!agent.!
!!
Caaibratiu:)T u prtcu t s d s iu ais inm ur iu d u calu t ai i drnmuid; al t t ctrructiu
ais
determining!d u urrtr t ai ux tiu
calui
!
Calorie:)Heat!required!to!raise!the!temperature!of!1!g!of!water!1®C!(actually,!from!4!to!5®C).!Mean!calorie!is!
equal!to!oneXhundredth!part!of!the!heat!required!to!raise!1!g!of!water!from!0!to!100®C.!
!
Capacitor:)An!electrical!device!that!has!the!ability!to!store!an!electrical!charge.!It!is!used!to!start!motors,!among!
other!purposes.!
!
Capaci)y,)refrigeratug:)T u a l db t a ru r uuratiu b dumt tr pard d urut t dt rumtdu uadi xpru us a
a
!
rate!of!heat!removal,!it!is!usually!measured!in!Btu/h!or!tons/24!h.!
!!
Capacity)reducer:)In!a!compre!!trt a sud cut nc a a cluaraicu ptckudt mtda lu cbl isur uast tr
nctti
bypass,!by!which!compressor!capacity!can!be!adjusted!without!otherwise!chaiu iu d u tpuratiu ctis tti i
Page 6
!
!
!
Bourdon)tube:)Tn u t ula tc mudal!bent!into!circular!shape!that!is!found!inside!a!pressure!gage.!
!
Brine:)Any!liquid!cooled!by!a!refrigerant!and!used!for!transmission!of!heat!without!a!change!in!its!state!
!!
Brine)system:)A b dum fl uru b r iu cttlus b a ru r uuratiu b dum c rcnladus dhrough!pipes!to!the!
point!wheru d u ru r uuratti iuususi
!
Britis)))serraa)))ui))))B)))))u:)The!amount!of!heat!required!to!raise!the!temperature!of!1!lb!of!water!1F.!It!is!also!the!
measure!of!the!amount!of!heat!removed!in!cooling!1!lb!of!water!1F!and!is!so!used!as!a!measure!of!
ru r uuratiu u
ucdi
!
Butane:)A bsrtcar tit eamma lu ru r uuraid n us dt a l m dus uxduid i mall ni d i
!!Calcium)chloride:)A!chemical!having!the!formula!CaCl2,!which,!in!granular!form,!is!used!as!a!drier.!This!
madur al tln lu i fladurt ais i d u pru uicu t laruu lnaittu t mt dnru mab s tldu ais plnu np d u
drier!unit!or!even!pass!into!the!system!beyond!the!drier.!
!!
Calcium)sulfate:)A!solid!chemical!of!the!formula!CaSO4,!which!may!be!used!as!a!drying!agent.!
!!
Caaibratiu:)T u prtcu t s d s iu ais inm ur iu d u calu t ai i drnmuid; al t t ctrructiu
ais
determining!d u urrtr t ai ux tiu
calui
!
Calorie:)Heat!required!to!raise!the!temperature!of!1!g!of!water!1®C!(actually,!from!4!to!5®C).!Mean!calorie!is!
equal!to!oneXhundredth!part!of!the!heat!required!to!raise!1!g!of!water!from!0!to!100®C.!
!
Capacitor:)An!electrical!device!that!has!the!ability!to!store!an!electrical!charge.!It!is!used!to!start!motors,!among!
other!purposes.!
!
Capaci)y,)refrigeratug:)T u a l db t a ru r uuratiu b dumt tr pard d urut t dt rumtdu uadi xpru us a
a
!
rate!of!heat!removal,!it!is!usually!measured!in!Btu/h!or!tons/24!h.!
!!
Capacity)reducer:)In!a!compre!!trt a sud cut nc a a cluaraicu ptckudt mtda lu cbl isur uast tr
nctti
bypass,!by!which!compressor!capacity!can!be!adjusted!without!otherwise!chaiu iu d u tpuratiu ctis tti i
Glossary of HVAC terms
Page 7
!
!
!
Capillarity:)T u actti b fl c d u nr acu t a l ln s i ctidacd fl d a!solid!(as!in!a!slender!tube)!is!raised!or!
lowered.!
Page 7
!
!
!
Capillarity:)T u actti b fl c d u nr acu t a l ln s i ctidacd fl d a!solid!(as!in!a!slender!tube)!is!raised!or!
lowered.!
Glossary of HVAC terms
Page 8
!
!
!
Capillary)tube:)Ii ru r uuratti practcut a dn u t mall idurial s amudur n us a a l ln s ru r uuraidXetfl
control!or!expansion!device!between!high!and!low!sides;!also!used!to!transmit!pressure!from!d u ui tdu nl
of!some!temperature!condrtl dt d u tpuratiu ulumuidi
!
Carbon)dioxide)ice:)Compressed!solid!CO2;!dry!ice.!
!!
Celsius:)A!thermometric!system!in!which!the!freezing!point!of!water!is!called!0®C!and!its!boiling!point!100®C!at!
normal!pressure.!T b dum n us i d u c uitic ctmmni db tr ru uarc fltrk ais al t b mt d nrtpuai
countries!and!Canada.!This!book!has!the!Celsius!value!of!each!Fahrenheit!temperature!in!parenthesis.!
!
Centrifugal)compressor:)A!compressor!employing!centrifugal!force!for!compression.!
!!
Centrifuge:)A sud cu tr uparatiu l ln s t s uruid sui tu b cuidr nual acttii
!
Change)of)air:)Iidrtsnctti t iuflt cluai ust tr ruc rcnladus a r dt a ctis ttius pacut mua nrus b d u
number!of!ctmpludu c aiuu pur ni d tmui
!
Change)of)state:)Change!from!one!state!to!another,!as!from!a!liquid!to!a!solid,!from!a!liquid!to!a!gas,!and!so!
forth.!
!
Charge:)The!amount!of!refrigerant!in!a!system.!
!!
Csiruey)effec):)T u duisuicb t a r tr ua i a sncd tr td ur durtcal pa auu dt r u fl un!heated!due!to!its!
lower!density!compared!with!that!of!the!surrounding!air!or!gas.!In!buildings,!the!tendency!toward!displacement,!
can us b d u s uruicu i dumpuradnrut t idurial uadus a r b ni uadus tnd su a r snu dt d u s uruicu i
density!of!outside!and!inside!air.!
!
Clearance:)Space!in!a!cylinder!not!occupied!by!a!piston!at!the!end!of!the!compression!stroke!or!volume!of!gas!
remaining!in!a!cylinder!at!the!same!point,!measured!in!percentage!of!piston!displacement.!
!
Ciefficieu)if)expauiiiu:)The!fracttial icrua u i luiud tr dtlnmu t a madur al per!degree!rise!in!
temperature.!
!
Ciefficieu))if)perfirrauce))sea))p))rpu:)Ratt t uatiu u ucd prtsncus dt d u uiurub nppl ust uac
!
expressed!in!the!same!thermal!units.!
!!
Coil:)Aib uatiu tr cttl iu ulument!made!of!pipe!or!tubing!connected!in!series.!
Page 8
!
!
!
Capillary)tube:)Ii ru r uuratti practcut a dn u t mall idurial s amudur n us a a l ln s ru r uuraidXetfl
control!or!expansion!device!between!high!and!low!sides;!also!used!to!transmit!pressure!from!d u ui tdu nl
of!some!temperature!condrtl dt d u tpuratiu ulumuidi
!
Carbon)dioxide)ice:)Compressed!solid!CO2;!dry!ice.!
!!
Celsius:)A!thermometric!system!in!which!the!freezing!point!of!water!is!called!0®C!and!its!boiling!point!100®C!at!
normal!pressure.!T b dum n us i d u c uitic ctmmni db tr ru uarc fltrk ais al t b mt d nrtpuai
countries!and!Canada.!This!book!has!the!Celsius!value!of!each!Fahrenheit!temperature!in!parenthesis.!
!
Centrifugal)compressor:)A!compressor!employing!centrifugal!force!for!compression.!
!!
Centrifuge:)A sud cu tr uparatiu l ln s t s uruid sui tu b cuidr nual acttii
!
Change)of)air:)Iidrtsnctti t iuflt cluai ust tr ruc rcnladus a r dt a ctis ttius pacut mua nrus b d u
number!of!ctmpludu c aiuu pur ni d tmui
!
Change)of)state:)Change!from!one!state!to!another,!as!from!a!liquid!to!a!solid,!from!a!liquid!to!a!gas,!and!so!
forth.!
!
Charge:)The!amount!of!refrigerant!in!a!system.!
!!
Csiruey)effec):)T u duisuicb t a r tr ua i a sncd tr td ur durtcal pa auu dt r u fl un!heated!due!to!its!
lower!density!compared!with!that!of!the!surrounding!air!or!gas.!In!buildings,!the!tendency!toward!displacement,!
can us b d u s uruicu i dumpuradnrut t idurial uadus a r b ni uadus tnd su a r snu dt d u s uruicu i
density!of!outside!and!inside!air.!
!
Clearance:)Space!in!a!cylinder!not!occupied!by!a!piston!at!the!end!of!the!compression!stroke!or!volume!of!gas!
remaining!in!a!cylinder!at!the!same!point,!measured!in!percentage!of!piston!displacement.!
!
Ciefficieu)if)expauiiiu:)The!fracttial icrua u i luiud tr dtlnmu t a madur al per!degree!rise!in!
temperature.!
!
Ciefficieu))if)perfirrauce))sea))p))rpu:)Ratt t uatiu u ucd prtsncus dt d u uiurub nppl ust uac
!
expressed!in!the!same!thermal!units.!
!!
Coil:)Aib uatiu tr cttl iu ulument!made!of!pipe!or!tubing!connected!in!series.!
Glossary of HVAC terms
Page 9
!
!
!
Cold)storage:)A!trade!or!process!of!preserving!perishables!on!a laruu calu b ru r uurattii
!
Comfort)chart:)A c ard tfl iu u uctdu dumpuradnru fl d srbX!nl dumpuradnru ais nm s tu ais
tmutmu a r mtttin b fl c d u u ucd t dar tn a r ctis tti on!human!comfort!maybe!compared.!
!
Compression)system:)A ru r uuratiu b dum i fl c d u pru nruXimposing!element!is!mechanically!
operated.!
!
Compressor:)T ad pard t a muc ai cal ru r uuratiu b dumt which!receives!the!refrigerant!vapor!at!low!
pressure!and!compresses!it!into!a!smaller!volume!at!higher!pressure.!
!
Compressor,)centrifugal:)A!nonXpt tdu s placumuid ctmpru tr d ad supuis ti cuidr nual u ucdt ad luast!
in!part,!for!pressure!rise.!
!
Compressor)displacement:)Ctmpru tr dtlnmu i cn c ic u tnis b mnltplb iu p dti arua b droke!by!
the!number!of!cylinders.!
!
Displacement!in!cubic!feet!per!minute:!
!!!!
!!
Compressor,)open<type:)A ctmpru tr fl d a af tr td ur mtd iu pardt uxduis iu d rtnu a!casing,!to!be!
sr dui b ai tnd su tnrcu t ptflurt d n ruln r iu a dnffiiu txt af ual t tr uln daluid rn iu ctidacd
udfluui a ixus ais mtd iu pardi
!
Cirpreiiir,)recipricatug:)A pt tduXdisplacement!compressor!with!a!piston!or!pistons!moving!in!a!straight!
line!but!alteriadulb i tppt du s ructti i
!
Compressor,)rotary:)Oiu i fl c ctmpru ti aaa ius i a cbl isur b rtdatti t a pt tduXdisplacement!
member.!
!
Compressor)booster:)A!compressor!for!very!low!pressures,!usually!discharging!intt d u ncton!line!of!another!
compressor.!
Page 9
!
!
!
Cold)storage:)A!trade!or!process!of!preserving!perishables!on!a laruu calu b ru r uurattii
!
Comfort)chart:)A c ard tfl iu u uctdu dumpuradnru fl d srbX!nl dumpuradnru ais nm s tu ais
tmutmu a r mtttin b fl c d u u ucd t dar tn a r ctis tti on!human!comfort!maybe!compared.!
!
Compression)system:)A ru r uuratiu b dum i fl c d u pru nruXimposing!element!is!mechanically!
operated.!
!
Compressor:)T ad pard t a muc ai cal ru r uuratiu b dumt which!receives!the!refrigerant!vapor!at!low!
pressure!and!compresses!it!into!a!smaller!volume!at!higher!pressure.!
!
Compressor,)centrifugal:)A!nonXpt tdu s placumuid ctmpru tr d ad supuis ti cuidr nual u ucdt ad luast!
in!part,!for!pressure!rise.!
!
Compressor)displacement:)Ctmpru tr dtlnmu i cn c ic u tnis b mnltplb iu p dti arua b droke!by!
the!number!of!cylinders.!
!
Displacement!in!cubic!feet!per!minute:!
!!!!
!!
Compressor,)open<type:)A ctmpru tr fl d a af tr td ur mtd iu pardt uxduis iu d rtnu a!casing,!to!be!
sr dui b ai tnd su tnrcu t ptflurt d n ruln r iu a dnffiiu txt af ual t tr uln daluid rn iu ctidacd
udfluui a ixus ais mtd iu pardi
!
Cirpreiiir,)recipricatug:)A pt tduXdisplacement!compressor!with!a!piston!or!pistons!moving!in!a!straight!
line!but!alteriadulb i tppt du s ructti i
!
Compressor,)rotary:)Oiu i fl c ctmpru ti aaa ius i a cbl isur b rtdatti t a pt tduXdisplacement!
member.!
!
Compressor)booster:)A!compressor!for!very!low!pressures,!usually!discharging!intt d u ncton!line!of!another!
compressor.!
Glossary of HVAC terms
Page
10
!
!
!
Condenser:)A!heatXtransfer!device!that!receives!highXpressure!vapor!at!temperatures!above!that!of!the!cooling!
medium,!such!as!air!or!water,!to!which!the!condenser!passes!latent!heat!from!the!refrigerant,!causing!the!
refrigerant!vapor!to!liquefy.!
!
Condensing:)T u prtcu t u d iu np laduid uad t daptr atti i trsur dt l lnu b a vapor.!
!
Condensing)unit:)A puc ic ru r uuratiu mac iu ctm iattit tr a u dui ru r uuraidt cti tiu t tiu
tr more!powerXdriven!compressors,!condensers,!liquid!receivers!(when!required),!and!the!regularly!
furnished!accessories.!
!
Condensing)unit,)sealed:)A!mechanical!condensing!unit,!in!which!the!compressor!and!compressor!motor!are!
enclosed!in!the!same!housing,!with!no!exdurial af tr af ualt d u ctmpru tr mtdtr tpuratiu in!the!
refrigerant!atmosphere.!
!
Ciud)ctiu,)serraa:)Passage!of!heat!from!one!point!to!another!by!transmission!of!molecular!energy!from!
!
partclu dt partclu d rtnu a ctisncdtri
!
Ciud))ctii)y,))serraa:)The!ability!of!a!material!to!pass!heat!from!one!point!to!another,!generally!expressed!in!
terms!of!Btu!per!hour!per!square!foot!of!material!per!inch!of!thickness!per!suuruu dumpuradnru s uruicui
!
Conductor,)electrical:)A!material!that!will!pass!an!electric!current!as!part!of!an!electrical!system.!
!!
Ciuuectug)rid:)A sud cu ctiiuctiu d u p dti dt a craik ais n us dt c aiuu rtdatiu mttti idt
ruc prtcatiu mtttit tr d cu dur at a rtm a rtdatiu craik af dt a ruc prtcatiu p dtii
!
Constant<pressure)valve:)A!valve!o!!d u d rtal iu dbput ru pti du dt pru nrut ltcadus i d u nctti l iu t
an!evaporator!to!maintain!a!desired!constant!pressure!in!the!evaporator!hiu ur d ai d u ma i ncttiXline!
pressure.!
!
Constant<temperature)valve:)A daldu t d u d rtal iu dbput ru pti du dt d u dumpuradnru t a d urmt datc
nl i T daldu ltcadus i d u nctti l iu t ai udaptradtr dt rusncu d u ru r uuratiu u ucd ti d u ct l dt on d
maintain!a!desired!minimum!temperature.!
!!
Control:)Aib sud cu tr ruunlatti t a b dum tr ctmptiuid i itrmal tpuratti u d ur mainal tr andtmatci I
andtmatct d u mpl catti d ad d ru pti du dt c aiuu t dumpuradnrut pru nrut tr aib td ur prtpurdb
whose!magnitude!is!to!be!regulated.!
Page
10
!
!
!
Condenser:)A!heatXtransfer!device!that!receives!highXpressure!vapor!at!temperatures!above!that!of!the!cooling!
medium,!such!as!air!or!water,!to!which!the!condenser!passes!latent!heat!from!the!refrigerant,!causing!the!
refrigerant!vapor!to!liquefy.!
!
Condensing:)T u prtcu t u d iu np laduid uad t daptr atti i trsur dt l lnu b a vapor.!
!
Condensing)unit:)A puc ic ru r uuratiu mac iu ctm iattit tr a u dui ru r uuraidt cti tiu t tiu
tr more!powerXdriven!compressors,!condensers,!liquid!receivers!(when!required),!and!the!regularly!
furnished!accessories.!
!
Condensing)unit,)sealed:)A!mechanical!condensing!unit,!in!which!the!compressor!and!compressor!motor!are!
enclosed!in!the!same!housing,!with!no!exdurial af tr af ualt d u ctmpru tr mtdtr tpuratiu in!the!
refrigerant!atmosphere.!
!
Ciud)ctiu,)serraa:)Passage!of!heat!from!one!point!to!another!by!transmission!of!molecular!energy!from!
!
partclu dt partclu d rtnu a ctisncdtri
!
Ciud))ctii)y,))serraa:)The!ability!of!a!material!to!pass!heat!from!one!point!to!another,!generally!expressed!in!
terms!of!Btu!per!hour!per!square!foot!of!material!per!inch!of!thickness!per!suuruu dumpuradnru s uruicui
!
Conductor,)electrical:)A!material!that!will!pass!an!electric!current!as!part!of!an!electrical!system.!
!!
Ciuuectug)rid:)A sud cu ctiiuctiu d u p dti dt a craik ais n us dt c aiuu rtdatiu mttti idt
ruc prtcatiu mtttit tr d cu dur at a rtm a rtdatiu craik af dt a ruc prtcatiu p dtii
!
Constant<pressure)valve:)A!valve!o!!d u d rtal iu dbput ru pti du dt pru nrut ltcadus i d u nctti l iu t
an!evaporator!to!maintain!a!desired!constant!pressure!in!the!evaporator!hiu ur d ai d u ma i ncttiXline!
pressure.!
!
Constant<temperature)valve:)A daldu t d u d rtal iu dbput ru pti du dt d u dumpuradnru t a d urmt datc
nl i T daldu ltcadus i d u nctti l iu t ai udaptradtr dt rusncu d u ru r uuratiu u ucd ti d u ct l dt on d
maintain!a!desired!minimum!temperature.!
!!
Control:)Aib sud cu tr ruunlatti t a b dum tr ctmptiuid i itrmal tpuratti u d ur mainal tr andtmatci I
andtmatct d u mpl catti d ad d ru pti du dt c aiuu t dumpuradnrut pru nrut tr aib td ur prtpurdb
whose!magnitude!is!to!be!regulated.!
Glossary of HVAC terms
Page 10
!
!
!!!
Control,)high<pressure:)A!pressureXresponsive!device!(usually!an!electric!switch)!actuated!directly!by!the!
refrigerantXvapor!pru nru ti d u u su t a ru r uuratiu b dum n nally!compressorXhead!pressure).!
!
Control,)low<pressure:)An!electric!switch,!responsive!to!pressure,!connected!into!the!low!pressure!part!of!a!
!
ru r uuratiu b dum n nallb clt u ad u pru nru ais tpui at!low!pressure).!
!
Control,)temperature:)An!electric!switch!or!relay!that!is!responsive!to!the!temperature!change!of!a!
!
d urmt datc nl tr ulumuidi
!
Ciuiectiu:)The!circulatorb mttti d ad tccnr i a en s ad a it ni trm dumpuradnrut tfl iu dt d u dar atti t
its!den!!db ais d u actti t urad dbi
!
Ciuiectiu,)firced:)Ctiductti ru nltiu rtm trcus c rcnlatti t a euid!as!by!a!fan,!jet,!or!pump.!
!
Cooling)tower,)water:)An!eiclt us sud cu tr udaptratdu cttling!water!by!contact!with!air.!
!
Cooling)unit:)A puc ic a rXdruatiu ctm iatti cti tiu t a muai tr a r c rcnlatti ais cttl iu fl d i
!
prescribed!temperature!limits.!
!!
Cooling)water:)Wadur n us tr ctisui atti tf!refrigerant.!Condenser!water.!
!
Cipper)paatug:)Ftrmatti t a ilm t ctppurt n nallb ti ctmpru tr flall t p dti t tr s c aruu daldu can
us
!
by!moisture!in!a!methyl!chloride!system.!
!!
Corrosive:)Had iu a c um callb su drnctdu u ucd ti mudal tccasionally!on!other!materials).!
!
Counter<fliw:)Ii d u uad uxc aiuu udfluui dflt en s t d u tppt du s ructti t etflt d u ctlsu d ptrtti t
tiu muutiu d u ctlsu d ptrtti t d u td uri
!
Critcaa)preii))re:)The!vapor!pressure!correspondiiu dt d u cr tcal dumpuradnrui
!
Critcaa))erpera)))re:)The!temperature!above!which!a!vapor!cannot!be!liqnuiust ruuarslu t pru nrui
!
Critcaa)ieaici)y:)The!velocity!above!fl c en s etfl dnr nluidi
!
Crohydrate:)Ai unductc r iu m xdnru t fladur ais aib ald m xus i prtptrtti dt give!the!lowest!freezing!
temperature.!
Page 10
!
!
!!!
Control,)high<pressure:)A!pressureXresponsive!device!(usually!an!electric!switch)!actuated!directly!by!the!
refrigerantXvapor!pru nru ti d u u su t a ru r uuratiu b dum n nally!compressorXhead!pressure).!
!
Control,)low<pressure:)An!electric!switch,!responsive!to!pressure,!connected!into!the!low!pressure!part!of!a!
!
ru r uuratiu b dum n nallb clt u ad u pru nru ais tpui at!low!pressure).!
!
Control,)temperature:)An!electric!switch!or!relay!that!is!responsive!to!the!temperature!change!of!a!
!
d urmt datc nl tr ulumuidi
!
Ciuiectiu:)The!circulatorb mttti d ad tccnr i a en s ad a it ni trm dumpuradnrut tfl iu dt d u dar atti t
its!den!!db ais d u actti t urad dbi
!
Ciuiectiu,)firced:)Ctiductti ru nltiu rtm trcus c rcnlatti t a euid!as!by!a!fan,!jet,!or!pump.!
!
Cooling)tower,)water:)An!eiclt us sud cu tr udaptratdu cttling!water!by!contact!with!air.!
!
Cooling)unit:)A puc ic a rXdruatiu ctm iatti cti tiu t a muai tr a r c rcnlatti ais cttl iu fl d i
!
prescribed!temperature!limits.!
!!
Cooling)water:)Wadur n us tr ctisui atti tf!refrigerant.!Condenser!water.!
!
Cipper)paatug:)Ftrmatti t a ilm t ctppurt n nallb ti ctmpru tr flall t p dti t tr s c aruu daldu can
us
!
by!moisture!in!a!methyl!chloride!system.!
!!
Corrosive:)Had iu a c um callb su drnctdu u ucd ti mudal tccasionally!on!other!materials).!
!
Counter<fliw:)Ii d u uad uxc aiuu udfluui dflt en s t d u tppt du s ructti t etflt d u ctlsu d ptrtti t
tiu muutiu d u ctlsu d ptrtti t d u td uri
!
Critcaa)preii))re:)The!vapor!pressure!correspondiiu dt d u cr tcal dumpuradnrui
!
Critcaa))erpera)))re:)The!temperature!above!which!a!vapor!cannot!be!liqnuiust ruuarslu t pru nrui
!
Critcaa)ieaici)y:)The!velocity!above!fl c en s etfl dnr nluidi
!
Crohydrate:)Ai unductc r iu m xdnru t fladur ais aib ald m xus i prtptrtti dt give!the!lowest!freezing!
temperature.!
Glossary of HVAC terms
Page 11
!
!
!
Cycle:)A ctmpludu ctnr u t tpuratti t fltrk iu en s ack dt a dartiu pt id mua nrus i d urmtsbiam c
!
terms.!Also!used!in!general!for!any!repeated!process!in!a!system.!
!!
Cycae,)defriitug:)T ad ptrtti t a ru r uuratti tpurattit fl c purm ts!the!cooling!unit!to!defrost.!
!
Cycae,)refrigeratiu:)A ctmpludu ctnr u t tpuratti t a ru r uuraid ack dt d u dartiu pt id mua nrus i
!
thermodynamic!terms.!Also!used!in!general!for!any!repeated!process!for!any!system.!
!!Daltiu’i)aaw)if)partaa)preii)re:))ac cti tdnuid t a m xdnru t ua u u adu d urmtsbiam callb a
d altiu tccnp us d u pacui T u nm t d u is d snal pru nru t d u cti tdnuid ulnal d u total!pressure!of!
the!mixture.!
!!
Defriitug:)The!removal!of!accumulated!ice!from!a!cooling!unit.!
!!
Degree)day:)A ni d a us ti dumpuradnru s uruicu ais tmu n us dt puc b d u itm ial uatiu ltas i
winter.!For!one!day!there!exist!as!many!degreeXsab a d uru aru suuruu Fa rui u d s uruicu i dumpuradnru
between!the!average!outside!air!temperature,!taken!over!a!24Xh!period,!and!a!temperature!of!65°F.!
!
Des)ridifier:)Ai a r cttlur n us tr ltflur iu d u mt dnru ctiduid t d u a r pa iu d rtnu di Ai a
trptti tr as trptti sud cu tr removing!moisture!from!the!air.!
!
Dehumidify:)To!remove!water!vapor!from!the!atmosphere!or!to!remove!water!or!liquid!from!stored!goods.!
!!
Dehydrator:)A!device!used!to!remove!moisture!from!the!refrigerant.!
!!
Density:)The!mass!or!weight!per!unit!of!volume.!
!!
Dew)point,)air:)The!temperature!at!fl c a puc ius amplu t a rt fl d it mt dnru assus tr rumtdust
!
completely!saturated.!The!temperature!at!which!the!air,!on!being!cooled,!gives!up!moisture!or!dew.!
!!
Differeutaa)if)a)ciu)riau:)T u s uruicu udfluui d u cnd i ais cnd tnd dumpuradnre.!A!valve!that!opens!at!
one!pressure!and!closes!at!another.!This!allows!a!system!to!adjust!itself!wid a m i mnm t tdurctrructtii
!
Direct)connected:)Dr dur ais sr duit a mtdtr ais ctmpru trt pt tdulb ctiiucdus i l ie!to!operate!at!
the!same!speed.!
Page 11
!
!
!
Cycle:)A ctmpludu ctnr u t tpuratti t fltrk iu en s ack dt a dartiu pt id mua nrus i d urmtsbiam c
!
terms.!Also!used!in!general!for!any!repeated!process!in!a!system.!
!!
Cycae,)defriitug:)T ad ptrtti t a ru r uuratti tpurattit fl c purm ts!the!cooling!unit!to!defrost.!
!
Cycae,)refrigeratiu:)A ctmpludu ctnr u t tpuratti t a ru r uuraid ack dt d u dartiu pt id mua nrus i
!
thermodynamic!terms.!Also!used!in!general!for!any!repeated!process!for!any!system.!
!!Daltiu’i)aaw)if)partaa)preii)re:))ac cti tdnuid t a m xdnru t ua u u adu d urmtsbiam callb a
d altiu tccnp us d u pacui T u nm t d u is d snal pru nru t d u cti tdnuid ulnal d u total!pressure!of!
the!mixture.!
!!
Defriitug:)The!removal!of!accumulated!ice!from!a!cooling!unit.!
!!
Degree)day:)A ni d a us ti dumpuradnru s uruicu ais tmu n us dt puc b d u itm ial uatiu ltas i
winter.!For!one!day!there!exist!as!many!degreeXsab a d uru aru suuruu Fa rui u d s uruicu i dumpuradnru
between!the!average!outside!air!temperature,!taken!over!a!24Xh!period,!and!a!temperature!of!65°F.!
!
Des)ridifier:)Ai a r cttlur n us tr ltflur iu d u mt dnru ctiduid t d u a r pa iu d rtnu di Ai a
trptti tr as trptti sud cu tr removing!moisture!from!the!air.!
!
Dehumidify:)To!remove!water!vapor!from!the!atmosphere!or!to!remove!water!or!liquid!from!stored!goods.!
!!
Dehydrator:)A!device!used!to!remove!moisture!from!the!refrigerant.!
!!
Density:)The!mass!or!weight!per!unit!of!volume.!
!!
Dew)point,)air:)The!temperature!at!fl c a puc ius amplu t a rt fl d it mt dnru assus tr rumtdust
!
completely!saturated.!The!temperature!at!which!the!air,!on!being!cooled,!gives!up!moisture!or!dew.!
!!
Differeutaa)if)a)ciu)riau:)T u s uruicu udfluui d u cnd i ais cnd tnd dumpuradnre.!A!valve!that!opens!at!
one!pressure!and!closes!at!another.!This!allows!a!system!to!adjust!itself!wid a m i mnm t tdurctrructtii
!
Direct)connected:)Dr dur ais sr duit a mtdtr ais ctmpru trt pt tdulb ctiiucdus i l ie!to!operate!at!
the!same!speed.!
Glossary of HVAC terms
Page 12
!
!
!
Direct)expansion:)A!system!in!which!the!evaporator!is!located!in!the!material!or!space!refrigerated!or!in!the!air!
!
c rcnlatiu pa auu ctmmni catiu fl d nc pacui
!
Discharge)gas:)Hot,!highXpressure!vapor!refrigerant,!whic!!!!!!a on d luf d u ctmpru tri
!
Displacement,)actual:)The!volume!of!gas!at!the!compressor!inlet!acdnallb mtdus i a u dui tmui
!
Diipaacereu),))seiretcaa:)The!total!volume!displaced!by!all!the!pistons!of!a!compressor!for!every!stroke!
!
snr iu a suii du idurdal n nallb mua ured!in!cubic!feet!per!minute).!
!
Drier:)Synonymous!with!dehydrator.!
!!
Dry<type)evaporator:)Ai udaptradtr t d u ctitintn dn u dbpu fl uru d u ru r uuraid rtm a pru nruX!
rusnc iu sud cu us idt tiu uis ais d u nctti l ne!connected!to!the!outlet!end.!
!
Duct:)A!passageway!made!of!sheet!metal!or!other!suitable!material,!not!necessarily!luak tu d,!used!for!
conveying!air!or!other!gas!at!low!pressure.!
!
Dust:)Ai a r n pui ti aurt tln t tl s partclu t uard b madur alt a s uruitadus rtm mtkui
!Economizer:)A!reservoir!or!chamber!wherein!energy!or!material!from!a!process!is!reclaimed!for!further!
useful!purpose.!
!
Efficieucy,)recsauicaa:)T u ratt t d u tndpnd t a mac iu dt d u ipnd i uln daluid ni ds.!
!
Efficieucy,)iia)re)ric:)T u ratt t d u dtlnmu t ua acdnallb pnmped!by!a!compressor!or!pump!to!the!
d utrutcal displacement!of!the!compressor.!
!
Ejector:)A sud cu d ad ntl iu datc pru nru dt n ls np a u en s dultc db i a ru dr cdus arua dt t da i a
ltflur datc pru nru ad d ad pt id t d ad en s rtm another!source!maybe!drawn!in.!
!
Element,)bimetallic:)Ai ulumuid trmus t dflt mudal ad iu s uruid ctuffic uid t d urmal uxpai tit nc
as!used!in!temperatureX!is catiu ais ctidrtll iu suvices.!
!
Emulsion:)A rulatdulb da lu n pui ti t mallt nd itd ctllt salt partcles!of!a!substance!in!a!liquid.!
!
Engine:)Prime!mover;!device!for!transforming!fuel!or!heat!energy!into!mechanical!energy.!
Page 12
!
!
!
Direct)expansion:)A!system!in!which!the!evaporator!is!located!in!the!material!or!space!refrigerated!or!in!the!air!
!
c rcnlatiu pa auu ctmmni catiu fl d nc pacui
!
Discharge)gas:)Hot,!highXpressure!vapor!refrigerant,!whic!!!!!!a on d luf d u ctmpru tri
!
Displacement,)actual:)The!volume!of!gas!at!the!compressor!inlet!acdnallb mtdus i a u dui tmui
!
Diipaacereu),))seiretcaa:)The!total!volume!displaced!by!all!the!pistons!of!a!compressor!for!every!stroke!
!
snr iu a suii du idurdal n nallb mua ured!in!cubic!feet!per!minute).!
!
Drier:)Synonymous!with!dehydrator.!
!!
Dry<type)evaporator:)Ai udaptradtr t d u ctitintn dn u dbpu fl uru d u ru r uuraid rtm a pru nruX!
rusnc iu sud cu us idt tiu uis ais d u nctti l ne!connected!to!the!outlet!end.!
!
Duct:)A!passageway!made!of!sheet!metal!or!other!suitable!material,!not!necessarily!luak tu d,!used!for!
conveying!air!or!other!gas!at!low!pressure.!
!
Dust:)Ai a r n pui ti aurt tln t tl s partclu t uard b madur alt a s uruitadus rtm mtkui
!Economizer:)A!reservoir!or!chamber!wherein!energy!or!material!from!a!process!is!reclaimed!for!further!
useful!purpose.!
!
Efficieucy,)recsauicaa:)T u ratt t d u tndpnd t a mac iu dt d u ipnd i uln daluid ni ds.!
!
Efficieucy,)iia)re)ric:)T u ratt t d u dtlnmu t ua acdnallb pnmped!by!a!compressor!or!pump!to!the!
d utrutcal displacement!of!the!compressor.!
!
Ejector:)A sud cu d ad ntl iu datc pru nru dt n ls np a u en s dultc db i a ru dr cdus arua dt t da i a
ltflur datc pru nru ad d ad pt id t d ad en s rtm another!source!maybe!drawn!in.!
!
Element,)bimetallic:)Ai ulumuid trmus t dflt mudal ad iu s uruid ctuffic uid t d urmal uxpai tit nc
as!used!in!temperatureX!is catiu ais ctidrtll iu suvices.!
!
Emulsion:)A rulatdulb da lu n pui ti t mallt nd itd ctllt salt partcles!of!a!substance!in!a!liquid.!
!
Engine:)Prime!mover;!device!for!transforming!fuel!or!heat!energy!into!mechanical!energy.!
Glossary of HVAC terms
Page 13
!
!
!
Enthalpy:)The!total!heat!content!of!a!substance,!compared!to!a!standard!value!32®F!or!0®C!for!water!vapor.!A!
measure!of!the!energy!content!of!a!system!per!unit!mass.!
!
Entropy:)T u ratt t d u uad assus dt a n daicu dt d u a tlndu dumperature!at!which!it!is!added.!
!
Equalizer:)A!piping!arrangement!to!maintain!a!common!liquid!level!or!pressure!between!two!or!more!
chambers.!
!
Eu)ectc)iia)tiu:)A tlntti t nc cticuidratti a dt adu a cti daid ruui iu pt id ad d u ltflu d ruui ig!
dumpuradnru tr d u tlnttii
!
Eiapiratie)ciudeuier:)A ru r uuraid ctisui ur ntl i iu d u udaptratti t fladur b a r ad d u ctisui ur
surface!as!a muai t s patiu uadi
!
Eiapiratie)ciiaiug:)T u prtcu t cttl iu b muai t d u udaptratti of!water!in!air.!
!
Evaporator:)A!device!in!which!the!refrigerant!evaporates!while!absorbing!heat.!
!!
Expauiiiu)iaaie,)a)))iratc:)A sud cu d ad ruunladu d u eow!of!refrigerant!from!the!liquid!line!into!the!
evaporator!to!maintain!a!constant!evaporator!pressure.!
!
Expauiiiu)iaaie,)serrii)atc:)A sud cu d ad ruunladu d u etfl t ru r uuraid idt ai udaptradtr t a dt
ma ida i ai udaptratti dumpuradnru i a suii du rulatti p dt d u dumpuradnru t a d urmt datc nl i
!
Extended)surface:)The!evaporator!or!condenser!surface!that!is!not!a!primary!surface.!Fins!or!other!surfaces!
that!transmit!heat!from!or!to!a!primary!surface,!which!is!part!of!the!refrigerant!container.!
!
External)equalizer:)Ii a d urmt datc uxpai ti daldut a dn u ctiiuctti rtm d u c am ur ctida i iu d u
pressure!actuated!element!of!the!valve!to!the!outlet!of!the!evaporator!coil.!A!device!to!compensate!for!
excessive!pressure!drop!through!the!coil.!
!Fahrenheit:)A!thermometric!system!in!which!32°F!denotes!the!freezing!point!of!water!and!212°F!the!boiling!
point!under!normal!pressure.!
!!
Fan:)An!airXmtd iu sud cu ctmpr iu a fl uult tr lasut ais tn iu tr tr icu pladui
Page 13
!
!
!
Enthalpy:)The!total!heat!content!of!a!substance,!compared!to!a!standard!value!32®F!or!0®C!for!water!vapor.!A!
measure!of!the!energy!content!of!a!system!per!unit!mass.!
!
Entropy:)T u ratt t d u uad assus dt a n daicu dt d u a tlndu dumperature!at!which!it!is!added.!
!
Equalizer:)A!piping!arrangement!to!maintain!a!common!liquid!level!or!pressure!between!two!or!more!
chambers.!
!
Eu)ectc)iia)tiu:)A tlntti t nc cticuidratti a dt adu a cti daid ruui iu pt id ad d u ltflu d ruui ig!
dumpuradnru tr d u tlnttii
!
Eiapiratie)ciudeuier:)A ru r uuraid ctisui ur ntl i iu d u udaptratti t fladur b a r ad d u ctisui ur
surface!as!a muai t s patiu uadi
!
Eiapiratie)ciiaiug:)T u prtcu t cttl iu b muai t d u udaptratti of!water!in!air.!
!
Evaporator:)A!device!in!which!the!refrigerant!evaporates!while!absorbing!heat.!
!!
Expauiiiu)iaaie,)a)))iratc:)A sud cu d ad ruunladu d u eow!of!refrigerant!from!the!liquid!line!into!the!
evaporator!to!maintain!a!constant!evaporator!pressure.!
!
Expauiiiu)iaaie,)serrii)atc:)A sud cu d ad ruunladu d u etfl t ru r uuraid idt ai udaptradtr t a dt
ma ida i ai udaptratti dumpuradnru i a suii du rulatti p dt d u dumpuradnru t a d urmt datc nl i
!
Extended)surface:)The!evaporator!or!condenser!surface!that!is!not!a!primary!surface.!Fins!or!other!surfaces!
that!transmit!heat!from!or!to!a!primary!surface,!which!is!part!of!the!refrigerant!container.!
!
External)equalizer:)Ii a d urmt datc uxpai ti daldut a dn u ctiiuctti rtm d u c am ur ctida i iu d u
pressure!actuated!element!of!the!valve!to!the!outlet!of!the!evaporator!coil.!A!device!to!compensate!for!
excessive!pressure!drop!through!the!coil.!
!Fahrenheit:)A!thermometric!system!in!which!32°F!denotes!the!freezing!point!of!water!and!212°F!the!boiling!
point!under!normal!pressure.!
!!
Fan:)An!airXmtd iu sud cu ctmpr iu a fl uult tr lasut ais tn iu tr tr icu pladui
Glossary of HVAC terms
Page 14
!
!
!
Fan,)centrifugal:)A!fan!rotor!or!wheel!within!a!scrollXtype!housing!and!including!drivingXmechanism!supports!
for!either!beltXsr du tr s rucd ctiiucttii
!
Fan,)propeller:)A!propeller!or!diskXdbpu fl uul fl d i a mtnitiu r iu tr pladu ais iclns iu sr d iuXmechanism!
supports!for!either!beltXdr!du tr s rucd ctiiucttii
!
Fan,)tube<axial:)A!diskXtype!wheel!within!a!cylinder,!a!set!of!airXun su daiu ltcadus u d ur u tru tr afur d u
wheel,!and!drivingXmechanism!supports!for!either!beltXdrive!or!direct!coiiucttii
Filter:)A!device!to!remove!solid!madur al rtm a en s b a dra i iu acttii
Flammability:)The!ability!of!a!material!to!burn.!
Faare)fitug:)A dbpu t ctiiucdtr tr tf dn iu d ad idtldu d u ear iu t d u dn e!to!provide!a!mechanical!
seal.!
!
Flash)gas:)T u ua ru nltiu rtm d u i daidaiutn udaptratti t d u ru r uuraid i a pru nruXreducing!
device!
dt cttl d u ru r uuraid dt d u udaptratti dumpuradnru t tained!at!the!reduced!pressure.!
!
Float)valve:)Valdu acdnadus b a etad mmur us i a l ln s container.!
!
Flooded)system:)A!system!in!which!the!refrigerant!enters!into!a!header!from!a!pressure!reducing!valve!and!the!
evaporator!maintains!a!liquid!level.!Opposed!to!dry!evaporator.!
!
Fluid:)A!gas!or!liquid.!
!!
Foaming:)Ftrmatti t a tam tr rtd t t l ru r uuraid snu dt rap s t l iu tnd t the!refrigerant!dissolved!
in!the!oil!when!the!pressure!is!suddenly!reduced.!This!occurs!when!the!compressor!operates;!and!if!large!!
lnaittu t ru r uuraid adu uui s tldust laruu lnaittu t t l mab m t lb tnd ais u carr us through!
the!refrigerant!lines.!
!
Freezeup:)Fa lnru t a ru r uuratti ni d dt tpuradu itrmallb snu dt trmatti t cu ad d u uxpai ti daldui T
u
valve!maybe!frozen!closed!or!open,!causing!improper!ru r uuratti i u d ur ca ui
!
Freezing)point:)The!temperature!at!which!a!liquid!will!solidify!upon!the!removal!of!heat.!
!!
Freon<12:)T u ctmmti iamu tr s c ltrts entrtmud aiu CCl F ).!
Page 14
!
!
!
Fan,)centrifugal:)A!fan!rotor!or!wheel!within!a!scrollXtype!housing!and!including!drivingXmechanism!supports!
for!either!beltXsr du tr s rucd ctiiucttii
!
Fan,)propeller:)A!propeller!or!diskXdbpu fl uul fl d i a mtnitiu r iu tr pladu ais iclns iu sr d iuXmechanism!
supports!for!either!beltXdr!du tr s rucd ctiiucttii
!
Fan,)tube<axial:)A!diskXtype!wheel!within!a!cylinder,!a!set!of!airXun su daiu ltcadus u d ur u tru tr afur d u
wheel,!and!drivingXmechanism!supports!for!either!beltXdrive!or!direct!coiiucttii
Filter:)A!device!to!remove!solid!madur al rtm a en s b a dra i iu acttii
Flammability:)The!ability!of!a!material!to!burn.!
Faare)fitug:)A dbpu t ctiiucdtr tr tf dn iu d ad idtldu d u ear iu t d u dn e!to!provide!a!mechanical!
seal.!
!
Flash)gas:)T u ua ru nltiu rtm d u i daidaiutn udaptratti t d u ru r uuraid i a pru nruXreducing!
device!
dt cttl d u ru r uuraid dt d u udaptratti dumpuradnru t tained!at!the!reduced!pressure.!
!
Float)valve:)Valdu acdnadus b a etad mmur us i a l ln s container.!
!
Flooded)system:)A!system!in!which!the!refrigerant!enters!into!a!header!from!a!pressure!reducing!valve!and!the!
evaporator!maintains!a!liquid!level.!Opposed!to!dry!evaporator.!
!
Fluid:)A!gas!or!liquid.!
!!
Foaming:)Ftrmatti t a tam tr rtd t t l ru r uuraid snu dt rap s t l iu tnd t the!refrigerant!dissolved!
in!the!oil!when!the!pressure!is!suddenly!reduced.!This!occurs!when!the!compressor!operates;!and!if!large!!
lnaittu t ru r uuraid adu uui s tldust laruu lnaittu t t l mab m t lb tnd ais u carr us through!
the!refrigerant!lines.!
!
Freezeup:)Fa lnru t a ru r uuratti ni d dt tpuradu itrmallb snu dt trmatti t cu ad d u uxpai ti daldui T
u
valve!maybe!frozen!closed!or!open,!causing!improper!ru r uuratti i u d ur ca ui
!
Freezing)point:)The!temperature!at!which!a!liquid!will!solidify!upon!the!removal!of!heat.!
!!
Freon<12:)T u ctmmti iamu tr s c ltrts entrtmud aiu CCl F ).!
Glossary of HVAC terms
Page 15
!
!
!
Frostback:)T u etts iu t l ln s rtm ai udaptradtr idt d u nctti l iut acctmpai us b rt d trmatti ti
the!nctti l iu i mt d ca u i
!
Furnace:)That!part!of!a!boiler!or!warmXnp uatiu plaid i fl c ctm n tti daku placui Al t a ctmpludu
uatiu ni d tr drai urr iu uad rtm nul u iu nrius dt d u a r nppl us dt a uatiu b dumi
!
Fusible)plug:)A!safety!plug!used!in!vessels!containing!refrigerant.!The!plug!is!designed!to!melt!at!high!
temperatures!(usually!about!165°F)!to!prevent!excessive!pressure!!rtm nr tiu d u du uli
!Gage:)Ai i drnmuid n us tr mua nr iu dar tn pru nru tr l ln s ludul i Stmutmu pullus uanuuni
!!!!
Gas:)The!vapor!state!of!a!material.!
!!
Generator:)A a c ctmptiuid t aib a trpttiXru r uuratti system.!
!
Graii)y,)ipecific:)The!density!of!a!standard!material!usually!compared!to!that!of!water!or!air.!
!!
Grille:)A!perforated!or!louvered!covering!for!an!air!passage,!usually!installed!in!a suflallt cu l iut tr ettri
!!Halide)torch:)A luak du dur uuiurallb n iu alct tl ais nri iu fl d a lnu eamu; fl ui d u ampl iu dn u
draws!in!halocarbon!refrigerant!vaport d u ctltnr t d u eamu c aiuu dt r u d uruuii Ga u dui t b d u
burning!halocarbon!is!phosgene,!a!deadly!gas!used!in!World!War!I!in!Europe!against!Allied!troops!(can!be!deadly!
ruad us i a clt us tr ctiiius area).!
!
!
Halogen:)Ai ulumuid rtm d u altuui urtnp d ad cti d t c ltr iut entr iut rtm iut ais ts iui Tflt
halogens!may!be!present!in!c!ltrtentrtcar ti ru r uuraid i
!
Heat:)Ba c trm t uiurub d ad mab u partallb ctidurdus idt td ur trm ais idt fl c all td ur trm mab
be!uitrulb ctidurdusi
!
Heat)of)fusion:)Latent!heat!involved!in!changing!between!the!solid!and!the!liquid!states.!
Page 15
!
!
!
Frostback:)T u etts iu t l ln s rtm ai udaptradtr idt d u nctti l iut acctmpai us b rt d trmatti ti
the!nctti l iu i mt d ca u i
!
Furnace:)That!part!of!a!boiler!or!warmXnp uatiu plaid i fl c ctm n tti daku placui Al t a ctmpludu
uatiu ni d tr drai urr iu uad rtm nul u iu nrius dt d u a r nppl us dt a uatiu b dumi
!
Fusible)plug:)A!safety!plug!used!in!vessels!containing!refrigerant.!The!plug!is!designed!to!melt!at!high!
temperatures!(usually!about!165°F)!to!prevent!excessive!pressure!!rtm nr tiu d u du uli
!Gage:)Ai i drnmuid n us tr mua nr iu dar tn pru nru tr l ln s ludul i Stmutmu pullus uanuuni
!!!!
Gas:)The!vapor!state!of!a!material.!
!!
Generator:)A a c ctmptiuid t aib a trpttiXru r uuratti system.!
!
Graii)y,)ipecific:)The!density!of!a!standard!material!usually!compared!to!that!of!water!or!air.!
!!
Grille:)A!perforated!or!louvered!covering!for!an!air!passage,!usually!installed!in!a suflallt cu l iut tr ettri
!!Halide)torch:)A luak du dur uuiurallb n iu alct tl ais nri iu fl d a lnu eamu; fl ui d u ampl iu dn u
draws!in!halocarbon!refrigerant!vaport d u ctltnr t d u eamu c aiuu dt r u d uruuii Ga u dui t b d u
burning!halocarbon!is!phosgene,!a!deadly!gas!used!in!World!War!I!in!Europe!against!Allied!troops!(can!be!deadly!
ruad us i a clt us tr ctiiius area).!
!
!
Halogen:)Ai ulumuid rtm d u altuui urtnp d ad cti d t c ltr iut entr iut rtm iut ais ts iui Tflt
halogens!may!be!present!in!c!ltrtentrtcar ti ru r uuraid i
!
Heat:)Ba c trm t uiurub d ad mab u partallb ctidurdus idt td ur trm ais idt fl c all td ur trm mab
be!uitrulb ctidurdusi
!
Heat)of)fusion:)Latent!heat!involved!in!changing!between!the!solid!and!the!liquid!states.!
Glossary of HVAC terms
Page 16
!
!
!
Heat,)sensible:)Huad d ad a tc adus fl d a c aiuu i dumpuradnru; puc ic uad uxc aiuu t dumpuradnrut
i
!
contrast!to!a!heat!interchange!in!which!a!change!of!state!(latent!heat)!occurs.!
!!
Hea),)ipecific)T u ratt t d u lnaitty!of!heat!required!to!raise!the!temperature!of!a!given!mass!of!any!
substance!1®!dt d u lnaitdb ruln rus dt ra u d u dumpuradnru t ai ulnal ma t a daisars n daicu
(usually!water!at!59®)!1®.!
!
Heat)of)iapirizatiu:)Latent!heat!involved!in!the!change!between!liquid!and!vapor!states.!
!!
Heat)pump:)A ru r uuratiu b dum umpltbus dt drai ur uad idt a pacu tr n daicui T u ctisui
ur
prtd su d u uadt fl lu d u udaptradtr arraiuus dt p ck np uad rtm a rt fladurt ais t trd i Bb f iu d
u etfl tf!the!refrigerant,!a!heatXpump!system!may!also!be!used!to!cool!the!space.!
!
Heatug)iyi)er:)Aib t d u udural uatiu mud ts n nallb durmus acctrs iu dt d u mud ts n us i d
uuiurattit nc a duam uatiut warmXa r uatiut ais d u l kui
!
Heatug)iyi)em,)electric:)Huatiu prtsncus b d u r u t dumpuradnru can us b d u pa auu t ai ulucdr c
cnrruid d rtnu a ctisncdtr ad iu a u ru daicu dt d u cnrruid etfli Ru suicu ulucdr cX!uatiu b dum
generally!consist!of!one!or!several!resistance!units!!i dallus i a ramu tr ca iut d u suuruu t uatiu u iu
d urmt datcallb ctidrtllusi
!
Heatug)iyi)er,)i)ear:)A uatiu b dum i fl c uad drai urrus rtm a t lur tr td ur tnrcu dt d
u
uatiu ni d b duam adt a tdut tr ultfl admt p ur c
pressure.!
!
Heatug)iyi)er,)iac))))r:)A!twoXp pu duam uatiu b dum uln ppus fl d d u iucu arb accu trb apparadn
dt purm d tpuratiu d u b tem!below!atmospheric!pressure.!
!
Heatug)iyi)er,)warr<air:)A!warmXa r uatiu plaid cti tiu t a uatiu ni d nul nrning!furnace)!
enclosed!in!a!casing!from!which!the!heated!air!is!distributed!to!various!rooms!of!the!building!through!ducts.!
!
Herretcaaay)ieaaed))ui):)A ru r uuratiu ni d ctida i iu d u mtdtr ais ctmpressor!in!a!sealed!container.!
!
High<pressure)cut)out:)A!control!device!connected!into!the!highXpru nru pard t a ru r uuratiu b dum dt
dtp
!
the!machine!when!the!pressure!becomes!excessive.!
Page 16
!
!
!
Heat,)sensible:)Huad d ad a tc adus fl d a c aiuu i dumpuradnru; puc ic uad uxc aiuu t dumpuradnrut
i
!
contrast!to!a!heat!interchange!in!which!a!change!of!state!(latent!heat)!occurs.!
!!
Hea),)ipecific)T u ratt t d u lnaitty!of!heat!required!to!raise!the!temperature!of!a!given!mass!of!any!
substance!1®!dt d u lnaitdb ruln rus dt ra u d u dumpuradnru t ai ulnal ma t a daisars n daicu
(usually!water!at!59®)!1®.!
!
Heat)of)iapirizatiu:)Latent!heat!involved!in!the!change!between!liquid!and!vapor!states.!
!!
Heat)pump:)A ru r uuratiu b dum umpltbus dt drai ur uad idt a pacu tr n daicui T u ctisui
ur
prtd su d u uadt fl lu d u udaptradtr arraiuus dt p ck np uad rtm a rt fladurt ais t trd i Bb f iu d
u etfl tf!the!refrigerant,!a!heatXpump!system!may!also!be!used!to!cool!the!space.!
!
Heatug)iyi)er:)Aib t d u udural uatiu mud ts n nallb durmus acctrs iu dt d u mud ts n us i d
uuiurattit nc a duam uatiut warmXa r uatiut ais d u l kui
!
Heatug)iyi)em,)electric:)Huatiu prtsncus b d u r u t dumpuradnru can us b d u pa auu t ai ulucdr c
cnrruid d rtnu a ctisncdtr ad iu a u ru daicu dt d u cnrruid etfli Ru suicu ulucdr cX!uatiu b dum
generally!consist!of!one!or!several!resistance!units!!i dallus i a ramu tr ca iut d u suuruu t uatiu u iu
d urmt datcallb ctidrtllusi
!
Heatug)iyi)er,)i)ear:)A uatiu b dum i fl c uad drai urrus rtm a t lur tr td ur tnrcu dt d
u
uatiu ni d b duam adt a tdut tr ultfl admt p ur c
pressure.!
!
Heatug)iyi)er,)iac))))r:)A!twoXp pu duam uatiu b dum uln ppus fl d d u iucu arb accu trb apparadn
dt purm d tpuratiu d u b tem!below!atmospheric!pressure.!
!
Heatug)iyi)er,)warr<air:)A!warmXa r uatiu plaid cti tiu t a uatiu ni d nul nrning!furnace)!
enclosed!in!a!casing!from!which!the!heated!air!is!distributed!to!various!rooms!of!the!building!through!ducts.!
!
Herretcaaay)ieaaed))ui):)A ru r uuratiu ni d ctida i iu d u mtdtr ais ctmpressor!in!a!sealed!container.!
!
High<pressure)cut)out:)A!control!device!connected!into!the!highXpru nru pard t a ru r uuratiu b dum dt
dtp
!
the!machine!when!the!pressure!becomes!excessive.!
Glossary of HVAC terms
Page 17
!
!
!
High)side:)T ad pard t d u ru r uuratiu b dum ctida i iu d u u Xpressure!refrigerant.!Also!the!term!used!to!
refer!to!d u ctisui iu ni d cti tiu t d u mtdtrt ctmpru trt ctisui urt ais rucu der!mounted!on!a!single!
base.!
!
High<iide)flia))iaaie:)A etad daldu d ad etad i u Xpressure!liquid.!Opens!on!an!increase!in!liquid!level.!
Hold)over:)In!an!evaporator,!the!abil db dt dab ctls afur uad rumtdal rtm d u udaptradtr stops.!
Horsepower:)A!unit!of!power.!Work!done!at!the!rate!of!33,000!lbXftm it tr ..5 l Xft i
H)))ridifier:)A!device!to!add!moisture!to!the!air.!
!!
Humidify:)To!add!water!vapor!to!the!atmosphere;!to!add!water!vapor!or!moisture!to!any!material.!
!!
Humidistat:)A ctidrtl sud cu acdnadus b c aiuu i nm s db ais n us tr andtmatc ctidrtl t rulatdu
!
humidity.!
!!
Humidity,)absolute:)T u suii du amtnid t fladur ctida ius i a suii du lnaitdb t a r n nallb muasured!in!
grains!of!water!per!pound!or!per!cubic!foot!of!air).!
!
H))ridi)y,)reaatie:)T u ratt t d u fladurXvapor!pressure!of!air!compared!to!the!vapor!pressure!it!would!have!
if!saturated!at!its!dryX!nl dumpuradnrui Vurb iuar dt d u ratt t d u amtnid t mtisture!contained!in!air!
ctmparus dt fl ad d ctnls tls ad d u ux tiu dumperature.!
!
H))ridi)y,)ipecific:)The!weight!of!vapor!associated!with!1!lb!of!dry!air;!also!termed!humidity(rati.!
!!
Hydrocarbons:)A!series!of!chemicals!of!similar!chemical!nature,!ranging!rtm mud aiu d u ma i cti tdnuid t
iadnral ua n d rtnu ndaiut tcdaiut ais t trd t dt uadb ln r catiu t l i All aru mtru tr lu eamma lui
Butane!and!isobutane!have!been!used!to!a!limited!extent!as!refrigerants.!
!
Hydrolysis:)Ruactti t a madur al,!such!as!FreonX12!or!methyl!chloride,!with!water.!Acid!materials!in!general!
are!formed.!
!
Hydrii)atc)preii))re:)The!pressure!due!to!liquid!in!a!container!that!contains!no!gas!space.!
!!
Hygrometer:)An!instrument!used!to!measure!moisture!in!the!air.!
!!
Hygroscope:)See!humidistat.!
Page 17
!
!
!
High)side:)T ad pard t d u ru r uuratiu b dum ctida i iu d u u Xpressure!refrigerant.!Also!the!term!used!to!
refer!to!d u ctisui iu ni d cti tiu t d u mtdtrt ctmpru trt ctisui urt ais rucu der!mounted!on!a!single!
base.!
!
High<iide)flia))iaaie:)A etad daldu d ad etad i u Xpressure!liquid.!Opens!on!an!increase!in!liquid!level.!
Hold)over:)In!an!evaporator,!the!abil db dt dab ctls afur uad rumtdal rtm d u udaptradtr stops.!
Horsepower:)A!unit!of!power.!Work!done!at!the!rate!of!33,000!lbXftm it tr ..5 l Xft i
H)))ridifier:)A!device!to!add!moisture!to!the!air.!
!!
Humidify:)To!add!water!vapor!to!the!atmosphere;!to!add!water!vapor!or!moisture!to!any!material.!
!!
Humidistat:)A ctidrtl sud cu acdnadus b c aiuu i nm s db ais n us tr andtmatc ctidrtl t rulatdu
!
humidity.!
!!
Humidity,)absolute:)T u suii du amtnid t fladur ctida ius i a suii du lnaitdb t a r n nallb muasured!in!
grains!of!water!per!pound!or!per!cubic!foot!of!air).!
!
H))ridi)y,)reaatie:)T u ratt t d u fladurXvapor!pressure!of!air!compared!to!the!vapor!pressure!it!would!have!
if!saturated!at!its!dryX!nl dumpuradnrui Vurb iuar dt d u ratt t d u amtnid t mtisture!contained!in!air!
ctmparus dt fl ad d ctnls tls ad d u ux tiu dumperature.!
!
H))ridi)y,)ipecific:)The!weight!of!vapor!associated!with!1!lb!of!dry!air;!also!termed!humidity(rati.!
!!
Hydrocarbons:)A!series!of!chemicals!of!similar!chemical!nature,!ranging!rtm mud aiu d u ma i cti tdnuid t
iadnral ua n d rtnu ndaiut tcdaiut ais t trd t dt uadb ln r catiu t l i All aru mtru tr lu eamma lui
Butane!and!isobutane!have!been!used!to!a!limited!extent!as!refrigerants.!
!
Hydrolysis:)Ruactti t a madur al,!such!as!FreonX12!or!methyl!chloride,!with!water.!Acid!materials!in!general!
are!formed.!
!
Hydrii)atc)preii))re:)The!pressure!due!to!liquid!in!a!container!that!contains!no!gas!space.!
!!
Hygrometer:)An!instrument!used!to!measure!moisture!in!the!air.!
!!
Hygroscope:)See!humidistat.!
Glossary of HVAC terms
Page 18
!
!
!Ice<reatug)ee)iiaaeu):)The!amount!of!heat!(144!Btu)!absorbed!by!1!lb!of!ice!at!32®F!in!liquefying!to!water!
at!32®F.!
!
Indirect)cooling)system:)See!brine!system.!
!!
Iufia)ratiu:)The!leakage!of!air!into!a!building!or!space.!
!!
Iui)aatiu:)A!material t ltfl uad ctisnctd dbi
!
Irritant)refrigerant:)Aib ru r uuraid d ad a ai rr datiu u ucd ti d e!eyes,!nose,!throat,!or!lungs.!
!
Isobutane:)A!hydrocarbon!refrigerant!used!to!a!l!m dus uxduidi Id eamma lui
!Kilowatt:)Unit!of!electrical!power!equal!to!1000!W,!or!1.34!hp,!approximately.!
!Lag)of)temperature)control:)T u sulab i actti t a dumpuradnruXru pti du ulumuid snu dt d u tmu
required!for!the!temperature!of!the!element!to!reach!the!surrounding!temperature.!
!
Latent)heat:)T u lnaitdb t uad d ad may!be!added!to!a!substance!during!a!change!of!state!without!causing!a!
temperature!change.!
!
La)eu)sea))if)eiapiratiu:)T u lnaitdb t uad ruln rus c aiu iu 2 l t l ln s idt a vapor!with!no!change!
in!temperature.!Reversible.!
!
Leak)detector:)A!device!used!to!detect!refrigerant!luak i a ru r uuratiu b dumi
!
Liquid:)T u dadu t a madur al i fl c d dtp nr acu i a du ul fl ll uctmu tr itidali D tiun us rtm
!
solid!or!vapor!forms.!
!!
Liquid)line:)The!tube!or!pipe!that!carries!the!refrigerant!liquis rtm d u ctisui ur tr rucu dur t a ru r
uuratiu
!
system!to!a!pressureXreducing!device.!
!!
Liquid)receiver:)That!part!of!the!condensing!unit!that!stores!the!liquid!refrigerant.!
Page 18
!
!
!Ice<reatug)ee)iiaaeu):)The!amount!of!heat!(144!Btu)!absorbed!by!1!lb!of!ice!at!32®F!in!liquefying!to!water!
at!32®F.!
!
Indirect)cooling)system:)See!brine!system.!
!!
Iufia)ratiu:)The!leakage!of!air!into!a!building!or!space.!
!!
Iui)aatiu:)A!material t ltfl uad ctisnctd dbi
!
Irritant)refrigerant:)Aib ru r uuraid d ad a ai rr datiu u ucd ti d e!eyes,!nose,!throat,!or!lungs.!
!
Isobutane:)A!hydrocarbon!refrigerant!used!to!a!l!m dus uxduidi Id eamma lui
!Kilowatt:)Unit!of!electrical!power!equal!to!1000!W,!or!1.34!hp,!approximately.!
!Lag)of)temperature)control:)T u sulab i actti t a dumpuradnruXru pti du ulumuid snu dt d u tmu
required!for!the!temperature!of!the!element!to!reach!the!surrounding!temperature.!
!
Latent)heat:)T u lnaitdb t uad d ad may!be!added!to!a!substance!during!a!change!of!state!without!causing!a!
temperature!change.!
!
La)eu)sea))if)eiapiratiu:)T u lnaitdb t uad ruln rus c aiu iu 2 l t l ln s idt a vapor!with!no!change!
in!temperature.!Reversible.!
!
Leak)detector:)A!device!used!to!detect!refrigerant!luak i a ru r uuratiu b dumi
!
Liquid:)T u dadu t a madur al i fl c d dtp nr acu i a du ul fl ll uctmu tr itidali D tiun us rtm
!
solid!or!vapor!forms.!
!!
Liquid)line:)The!tube!or!pipe!that!carries!the!refrigerant!liquis rtm d u ctisui ur tr rucu dur t a ru r
uuratiu
!
system!to!a!pressureXreducing!device.!
!!
Liquid)receiver:)That!part!of!the!condensing!unit!that!stores!the!liquid!refrigerant.!
Glossary of HVAC terms
Page 19
!
!
!
Load:)The!required!rate!of!heat!removal.!
!!
Low<pressure)control:)An!electric!switc!!ais pru nru ru pti du ulumuid ctiiucdus idt d u nctti su t a
ru r uuratiu ni d dt ctidrtl d u tpuratti t d u b dumi
!
Low)side:)T ad pard t a ru r uuratiu b dumt fl c itrmallb tpuradu nisur ltfl pru nrut a tppt us dt d u
!
high!side.!Also!used!to!refer!to!the!evaporator.!
!!
Low<iide)flia):)A!valve!operated!by!the!lowXpressure!liquid,!which!opens!at!a!low!level!and!closes!at!a!high!
level.!
!Main:)A p pu tr sncd tr s dr ntiu dt tr ctlluctiu ctis toned!air!from!various!branches.!
!!!!
Manometer:)A!UXshaped!liquidXillus dn u tr mua nr iu pru nru s uruicu i
!
Mecsauicaa)efficieucy:)T u ratt t fltrk stiu b a mac iu dt d u fltrk sone!on!it!or!energy!used!by!it.!
!
Mechanical)equivalent)of)heat:)An!energyXctidur ti ratt t 7i27 l Xf =!1!Btu.!
!
Methyl)chloride:)A!refrigerant!having!the!chemical!formula!CH3Cl.!
!!
Micriu))µu:)A!unit!of!length;!the!thousandth!part!of!1!mm!or!the!millionth!part!of!a!meter.!
!!
Mollier)chart:)A urap cal rupru uidatti t d urmal prtpurtu t en s t fl d dtdal uat!and!entropy!as!
coordinates.!
!
Motor:)A!device!for!transforming!electrical!energy!into!mechanical!energy.!
!!
Motor)capacitor:)A sud cu su uius dt mprtdu d u dartiu a l db t singleXp a u isnctti mtdtr i
!Noncondensables:)Foreign!gases!mixed!with!a!refrigerant,!which!cannot!be!condensed!into!liquid!form!at!
the!temperatures!and!pressures!at!which!the!refrigerant!condenses.!
Page 19
!
!
!
Load:)The!required!rate!of!heat!removal.!
!!
Low<pressure)control:)An!electric!switc!!ais pru nru ru pti du ulumuid ctiiucdus idt d u nctti su t a
ru r uuratiu ni d dt ctidrtl d u tpuratti t d u b dumi
!
Low)side:)T ad pard t a ru r uuratiu b dumt fl c itrmallb tpuradu nisur ltfl pru nrut a tppt us dt d u
!
high!side.!Also!used!to!refer!to!the!evaporator.!
!!
Low<iide)flia):)A!valve!operated!by!the!lowXpressure!liquid,!which!opens!at!a!low!level!and!closes!at!a!high!
level.!
!Main:)A p pu tr sncd tr s dr ntiu dt tr ctlluctiu ctis toned!air!from!various!branches.!
!!!!
Manometer:)A!UXshaped!liquidXillus dn u tr mua nr iu pru nru s uruicu i
!
Mecsauicaa)efficieucy:)T u ratt t fltrk stiu b a mac iu dt d u fltrk sone!on!it!or!energy!used!by!it.!
!
Mechanical)equivalent)of)heat:)An!energyXctidur ti ratt t 7i27 l Xf =!1!Btu.!
!
Methyl)chloride:)A!refrigerant!having!the!chemical!formula!CH3Cl.!
!!
Micriu))µu:)A!unit!of!length;!the!thousandth!part!of!1!mm!or!the!millionth!part!of!a!meter.!
!!
Mollier)chart:)A urap cal rupru uidatti t d urmal prtpurtu t en s t fl d dtdal uat!and!entropy!as!
coordinates.!
!
Motor:)A!device!for!transforming!electrical!energy!into!mechanical!energy.!
!!
Motor)capacitor:)A sud cu su uius dt mprtdu d u dartiu a l db t singleXp a u isnctti mtdtr i
!Noncondensables:)Foreign!gases!mixed!with!a!refrigerant,!which!cannot!be!condensed!into!liquid!form!at!
the!temperatures!and!pressures!at!which!the!refrigerant!condenses.!
Glossary of HVAC terms
Page 21
!
!
!Oil)trap:)A!device!to!separate!oil!from!the!highXpressure!vapor!from!the!compressor.!Usually!contains!a!
etad daldu dt rudnri d u t l to!the!compressor!crankcase.!
!
!
Output:)Nud ru r uuratti prtsncus b d u b dumi
!
Ozone:)T u O trm t txbuuit tmutmu n us i a r ctis tti iu tr ctlsXstorage!rooms!to!eliminate!odors,!
can!be!toxic!in!concuidratti t 5i. ppm ais tduri
!Packing:)T u dnffiiu artnis a af dt pruduid en s luakauu udfluui d u af ais pard artnis d u
afi
!!!!
Packless)valve:)A!valve!that!does!not!use!packing!to!prevent!leaks!around!the!valve!stem.!Flexible!material!is!
!
n nallb n us dt ual aua i d luak ais tll purm d dalve!movement.!
!
Performance)factor:)T u ratt t d u uad mtdus b a ru r uuratiu b dum dt uad uln daluid t d u
uiuruy!n usi Var u fl d ctis tti i
!
Phosphorous)pentoxide:)Ai uffic uid sr ur madur al d ad uctmu unmmb ruactiu fl d mt dnru ais uicu
!
not!used!alone!as!a!drying!agent.!
!!
Pour)point,)oil:)The!temperature!below,!which!the!oil!surface!will!not!change!whui d u t l ctida iur tldusi
!
Power:)The!rate!of!doing!work!measured!in!horsepower,!flaa t k ltflaa t ais t trd i
!
Power)factor,)electrical)devices:)T u ratt t flaa dt dtldXamperes!in!ai alduriatiu cnrruid c rcn di
!
Pressure:)The!force!exerted!per!unit!of!area.!
!!
Pressure)drop:)Lt i pru nrut a rtm tiu uis t a ru r uuraid l iu dt d u td urt snu dt r cttit datc uast
!
and!the!like.!
!!
Pressure)gage:)See!Gage.!
!!
Pressure<relief)valve:)A!valve!or!rupture!member!designed!to!relieve!excu du pru nru andtmatcallbi
Page 21
!
!
!Oil)trap:)A!device!to!separate!oil!from!the!highXpressure!vapor!from!the!compressor.!Usually!contains!a!
etad daldu dt rudnri d u t l to!the!compressor!crankcase.!
!
!
Output:)Nud ru r uuratti prtsncus b d u b dumi
!
Ozone:)T u O trm t txbuuit tmutmu n us i a r ctis tti iu tr ctlsXstorage!rooms!to!eliminate!odors,!
can!be!toxic!in!concuidratti t 5i. ppm ais tduri
!Packing:)T u dnffiiu artnis a af dt pruduid en s luakauu udfluui d u af ais pard artnis d u
afi
!!!!
Packless)valve:)A!valve!that!does!not!use!packing!to!prevent!leaks!around!the!valve!stem.!Flexible!material!is!
!
n nallb n us dt ual aua i d luak ais tll purm d dalve!movement.!
!
Performance)factor:)T u ratt t d u uad mtdus b a ru r uuratiu b dum dt uad uln daluid t d u
uiuruy!n usi Var u fl d ctis tti i
!
Phosphorous)pentoxide:)Ai uffic uid sr ur madur al d ad uctmu unmmb ruactiu fl d mt dnru ais uicu
!
not!used!alone!as!a!drying!agent.!
!!
Pour)point,)oil:)The!temperature!below,!which!the!oil!surface!will!not!change!whui d u t l ctida iur tldusi
!
Power:)The!rate!of!doing!work!measured!in!horsepower,!flaa t k ltflaa t ais t trd i
!
Power)factor,)electrical)devices:)T u ratt t flaa dt dtldXamperes!in!ai alduriatiu cnrruid c rcn di
!
Pressure:)The!force!exerted!per!unit!of!area.!
!!
Pressure)drop:)Lt i pru nrut a rtm tiu uis t a ru r uuraid l iu dt d u td urt snu dt r cttit datc uast
!
and!the!like.!
!!
Pressure)gage:)See!Gage.!
!!
Pressure<relief)valve:)A!valve!or!rupture!member!designed!to!relieve!excu du pru nru andtmatcallbi
Glossary of HVAC terms
Page 20
!
!
!
Psychrometric)chart:)A c ard n us dt sudurm iu d u puc ic dtlnmut uad ctiduidt sufl pt idt rulatdu
humidity,!absolute!humidity,!and!wetX!and!dryXbulb!temperatures,!knowing!any!two!independent!items!of!those!
muittiusi
!
Purging:)The!act!of!blowing!out!refrigerant!gas!from!a!refrigerant!containing!vessel!usually!for!the!purpose!of!
removing!!nonXcondensables.!
!
Pyrometer:)An!instrument!for!the!measurement!of!high!temperatures.!
!!Radiatiu:)The!passage!of!heat!from!one!object!to!another!without!warming!the!space!between.!The!heat!
pa us b fladu mttti m lar dt l u di
!!
Refrigerant:)T u mus nm t uad drai ur i a ru r uuratiu b dum d ad p ck np uad by!evaporatiu ad a ltfl
!
temperature!and!gives!up!heat!by!condensing!at!a!higher!temperature.!
!!
Refrigeratug)iyi)er:)A ctm iatti t pard i fl c a ru r uuraid c rcnladus tr d u pnrpt u t uxdractiu
!
heat.!
!!
Reaatie)s)ridi)y:)T u ratt t d u fladurXvapor!pressure!of!air!compared!to!the!vapor!pressure!it!would!have!
if!saturated!at!its!dryXbulb!temperadnrui Vurb iuarlb d u ratt t the!amount!of!moisture!contained!in!air!
compared!to!what!it!could!hols ad d u ux tiu dumpuradnrui
!
Relief)valve:)A!valve!designed!to!open!at!excessively!high!pressures!to!allow!the!refrigerant!to!escape.!
!!
Resistance,)electrical:)T u tppt tti dt ulucdr cXcnrruid etflt mua nrus i t m i
!
Resistance,)thermal:)The!reciprtcal t d urmal ctisnctd dbi
!
Room)cooler:)A!cooling!element!ftr a rttmi Ii a r ctis tti iut a sud cu tr ctis tti iu mall!volumes!of!air!
for!comfort.!
!
Rotary)compressor:)A ctmpru tr i fl c ctmpru ti aaa ius i a cbl isur b rtdatti t a um ras al
!
member.!
!!
R)uuiug)tre:)U nallb is cadu purcuid t tmu a!refrigerant!compressor!operates.!
Page 20
!
!
!
Psychrometric)chart:)A c ard n us dt sudurm iu d u puc ic dtlnmut uad ctiduidt sufl pt idt rulatdu
humidity,!absolute!humidity,!and!wetX!and!dryXbulb!temperatures,!knowing!any!two!independent!items!of!those!
muittiusi
!
Purging:)The!act!of!blowing!out!refrigerant!gas!from!a!refrigerant!containing!vessel!usually!for!the!purpose!of!
removing!!nonXcondensables.!
!
Pyrometer:)An!instrument!for!the!measurement!of!high!temperatures.!
!!Radiatiu:)The!passage!of!heat!from!one!object!to!another!without!warming!the!space!between.!The!heat!
pa us b fladu mttti m lar dt l u di
!!
Refrigerant:)T u mus nm t uad drai ur i a ru r uuratiu b dum d ad p ck np uad by!evaporatiu ad a ltfl
!
temperature!and!gives!up!heat!by!condensing!at!a!higher!temperature.!
!!
Refrigeratug)iyi)er:)A ctm iatti t pard i fl c a ru r uuraid c rcnladus tr d u pnrpt u t uxdractiu
!
heat.!
!!
Reaatie)s)ridi)y:)T u ratt t d u fladurXvapor!pressure!of!air!compared!to!the!vapor!pressure!it!would!have!
if!saturated!at!its!dryXbulb!temperadnrui Vurb iuarlb d u ratt t the!amount!of!moisture!contained!in!air!
compared!to!what!it!could!hols ad d u ux tiu dumpuradnrui
!
Relief)valve:)A!valve!designed!to!open!at!excessively!high!pressures!to!allow!the!refrigerant!to!escape.!
!!
Resistance,)electrical:)T u tppt tti dt ulucdr cXcnrruid etflt mua nrus i t m i
!
Resistance,)thermal:)The!reciprtcal t d urmal ctisnctd dbi
!
Room)cooler:)A!cooling!element!ftr a rttmi Ii a r ctis tti iut a sud cu tr ctis tti iu mall!volumes!of!air!
for!comfort.!
!
Rotary)compressor:)A ctmpru tr i fl c ctmpru ti aaa ius i a cbl isur b rtdatti t a um ras al
!
member.!
!!
R)uuiug)tre:)U nallb is cadu purcuid t tmu a!refrigerant!compressor!operates.!
Glossary of HVAC terms
Page 22
!
!
!Saturated)vapor:)Vapor!not!superheated!but!of!100!percent!quality,!that!is,!containing!no!unvaporized!
liquid.!
!
Seaa,)isaf:)A muc ai cal b dum t pard tr pruduitiu ua luakauu udfluui a rtdatiu af ais a
dattiarb
!
crankcase.!
!!
Sealed)unit:)Suu urmutcallb ualus i di
!
Shell)and)tube:)Pertaining!to!heat!exchangers!in!which!a!coil!of!tubing!or!pipe!is!contained!in!a!shell!or!
!
ctida iuri T u p pu prtd sus fl d tpui iu dt alltfl d u pa auu t a en s d rtnu dt fl lu the!shell!is!also!
provided!with!an!inlud ais tndlud tr a en s etfli
!
Silica)gel:)A!drier!material!having!the!formula!SiO2.!
!!
Sludge:)A suctmpt tti prtsncd trmus i a ru r uuraid snu dt mpnr tu i d u t l tr snu dt mt dnrui Slnsges!
may!be!gummy!or!hard.!
!
Soda)lime:)A!material!used!for!removing!moisture.!Not!rectmmuisus tr ru r uuratti n ui
!
Solenoid)valve:)A daldu tpuius b a mauiutc u ucd t ai ulucdr c cnrruid d rtnu a tluit s ct li
!
Solid:)T u dadu t maaur i fl c a trcu cai u uxurdus i a stfliflars s ructti tilb fl ui itd ctiiius.!As!
s tiun us rtm en s i
!
Solubility:)T u a l db t tiu madur al dt uidur idt tlntti fl d another.!
!
Sia))tiu:)The!homogeneous!mixture!of!two!or!more!materials.!
!!
Specific)graii)y:)The!weight!of!a!volume!of!a!material!compared!to!the!weight!of!the!same!volume!of!water.!
!!
Specific)sea):)T u lnaitdb t uad ruln rus dt ra u d u dumpuradnru t a suii du ma t a madur al dt a
suii du amtnid ctmparus dt d ad ruln rus dt ra u d u dumpuradnru t d u amu ma t water!the!same!
amount.!May!be!expressed!as!Btu/!pound/!degrees!Fahrenheit.!
!
Specific)iia)re:)T u dtlnmu t a suii du flu u d t a madur ali U nallb uxpru us i cn c uud pur ptund.!The!
reciprocal!of!density.!
Page 22
!
!
!Saturated)vapor:)Vapor!not!superheated!but!of!100!percent!quality,!that!is,!containing!no!unvaporized!
liquid.!
!
Seaa,)isaf:)A muc ai cal b dum t pard tr pruduitiu ua luakauu udfluui a rtdatiu af ais a
dattiarb
!
crankcase.!
!!
Sealed)unit:)Suu urmutcallb ualus i di
!
Shell)and)tube:)Pertaining!to!heat!exchangers!in!which!a!coil!of!tubing!or!pipe!is!contained!in!a!shell!or!
!
ctida iuri T u p pu prtd sus fl d tpui iu dt alltfl d u pa auu t a en s d rtnu dt fl lu the!shell!is!also!
provided!with!an!inlud ais tndlud tr a en s etfli
!
Silica)gel:)A!drier!material!having!the!formula!SiO2.!
!!
Sludge:)A suctmpt tti prtsncd trmus i a ru r uuraid snu dt mpnr tu i d u t l tr snu dt mt dnrui Slnsges!
may!be!gummy!or!hard.!
!
Soda)lime:)A!material!used!for!removing!moisture.!Not!rectmmuisus tr ru r uuratti n ui
!
Solenoid)valve:)A daldu tpuius b a mauiutc u ucd t ai ulucdr c cnrruid d rtnu a tluit s ct li
!
Solid:)T u dadu t maaur i fl c a trcu cai u uxurdus i a stfliflars s ructti tilb fl ui itd ctiiius.!As!
s tiun us rtm en s i
!
Solubility:)T u a l db t tiu madur al dt uidur idt tlntti fl d another.!
!
Sia))tiu:)The!homogeneous!mixture!of!two!or!more!materials.!
!!
Specific)graii)y:)The!weight!of!a!volume!of!a!material!compared!to!the!weight!of!the!same!volume!of!water.!
!!
Specific)sea):)T u lnaitdb t uad ruln rus dt ra u d u dumpuradnru t a suii du ma t a madur al dt a
suii du amtnid ctmparus dt d ad ruln rus dt ra u d u dumpuradnru t d u amu ma t water!the!same!
amount.!May!be!expressed!as!Btu/!pound/!degrees!Fahrenheit.!
!
Specific)iia)re:)T u dtlnmu t a suii du flu u d t a madur ali U nallb uxpru us i cn c uud pur ptund.!The!
reciprocal!of!density.!
Glossary of HVAC terms
Page 23
!
!
!
Spray)pond:)An!arrangement!for!lowering!the!temperature!of!water!by!evaporatdu cttl iu t d u fladur i
contact!with!outside!air.!The!water!to!be!cooled!is!sprayed!by!nozzles!into!the!space!above!a!body!of!previously!
cooled!water!and!allowed!to!fall!by!gravity!into!it.!
!
Steam:)Water!in!the!vapor!phase.!
!!
Steam)trap:)A!device!for!allowing!the!passage!of!condensate,!or!air!and!condensate,!and!pruduitiu d u
!
passage!of!steam.!
!!
Subcooled:)Cooled!below!the!condensing!temperature!correspois iu dt d u ux tiu pru nrui
!
S))bairatiu:)The!change!from!a!solid!to!a!vapor!state!without!an!intermediate!liquid!state.!
!!
S))ctiu)aiue:)The!tube!or!pipe!that!carries!refrigerant!vapor!from!the!evaporator!to!the!compressor!inlet.!
!!
S)ctiu)preii)re:)Pressure!on!the!nctti su t d u ctmpru tri
!
Superheater:)A!heat!exchanger!used!ti ettsus udaptradtr t fl uru i td l ln s ti d flab dt uidur d u
!
evaporator!is!cooled!by!supplying!heat!to!dry!and!superheat!the!wet!vapor!leaving!the!evaporator.!
!!
Sweatug:)Ctisui atti t mt dnru rtm d u a r ti nr acu ultfl d u suflXpoint!temperature.!
!
System:)A uatiu tr ru r uuratiu c umu tr mac iut n nallb ctiiius dt d t u pard i ctidacd fl d d u
uatiu tr ru r uuratiu mus nmi
!Temperature:)Heat!level!or!pressure.!The!thermal!state!of!a!body!with!respect!to!its!ability!to!pick!up!heat!
from!or!pass!heat!to!another!body.!
!!Therraa)ciud))ctii)y:)The!ability!of!a!material!to!conduct!heat!from!one!point!to!another.!Indicated!
in!terms!of!Btu/per!hour!per!square!foot!per!inches!of!thickness!per!degrees!Fahrenheit.!
Page 23
!
!
!
Spray)pond:)An!arrangement!for!lowering!the!temperature!of!water!by!evaporatdu cttl iu t d u fladur i
contact!with!outside!air.!The!water!to!be!cooled!is!sprayed!by!nozzles!into!the!space!above!a!body!of!previously!
cooled!water!and!allowed!to!fall!by!gravity!into!it.!
!
Steam:)Water!in!the!vapor!phase.!
!!
Steam)trap:)A!device!for!allowing!the!passage!of!condensate,!or!air!and!condensate,!and!pruduitiu d u
!
passage!of!steam.!
!!
Subcooled:)Cooled!below!the!condensing!temperature!correspois iu dt d u ux tiu pru nrui
!
S))bairatiu:)The!change!from!a!solid!to!a!vapor!state!without!an!intermediate!liquid!state.!
!!
S))ctiu)aiue:)The!tube!or!pipe!that!carries!refrigerant!vapor!from!the!evaporator!to!the!compressor!inlet.!
!!
S)ctiu)preii)re:)Pressure!on!the!nctti su t d u ctmpru tri
!
Superheater:)A!heat!exchanger!used!ti ettsus udaptradtr t fl uru i td l ln s ti d flab dt uidur d u
!
evaporator!is!cooled!by!supplying!heat!to!dry!and!superheat!the!wet!vapor!leaving!the!evaporator.!
!!
Sweatug:)Ctisui atti t mt dnru rtm d u a r ti nr acu ultfl d u suflXpoint!temperature.!
!
System:)A uatiu tr ru r uuratiu c umu tr mac iut n nallb ctiiius dt d t u pard i ctidacd fl d d u
uatiu tr ru r uuratiu mus nmi
!Temperature:)Heat!level!or!pressure.!The!thermal!state!of!a!body!with!respect!to!its!ability!to!pick!up!heat!
from!or!pass!heat!to!another!body.!
!!Therraa)ciud))ctii)y:)The!ability!of!a!material!to!conduct!heat!from!one!point!to!another.!Indicated!
in!terms!of!Btu/per!hour!per!square!foot!per!inches!of!thickness!per!degrees!Fahrenheit.!
Glossary of HVAC terms
Page 24
!
!
!
Thermocouple:)A sud cu cti tiu t dflt ulucdr cal ctisncdtr ad iu dflt onictti —one!at!a!point!whose!
temperature!is!to!be!measured,!and!the!other!at!a!known!temperature.!The!temperature!between!the!two!
onictti sudurm ius b d u madur al c aracdur tc ais d u ulucdr cal ptduital etup.!
!
Thermodynamics:)The!science!of!the!mechanics!of!heat.!
!!
Thermometer:)A sud cu tr is catiu dumpuradnrui
!
Thermostat:)A!temperatureXactuated!switch.!
!!
Tiu)if)refrigeratiu:)Ru r uuratti uln daluid dt d u multiu t 2 dti t cu pur 3 i 77t555 Bdntsab,!12,000!
Btu/h,!or!200!Btu/min.!
!
Total)heat:)T u dtdal uad assus dt a ru r uuraid a tdu ai ar drarb dartiu pt id dt r iu d dt a u dui ud t
ctis tti n nallb uxpru us i Bdntptnisni Ftr i daicut i a npurXheated!gas,!the!combined!heat!added!to!!!
t!u l ln s iucu arb dt ra u d dumpuradnru rtm ai ar drarb dartiu pt id dt d u uvaporatti dumpuradnru
dt ctmpludu udaptrattit ais dt ra u d u dumpuradnru dt d u iial dumpuradnru fl uru d u ua npur
uadusi
!
Total)pressure:)Ii en s etflt d u nm t datc pru nru ais dultc db pru nrui
!
T)rb)aeu)fliw:)Fln s etfl i fl c d u en s mtdu drai dur ulb a flull a i d u s ructti t d u dn u tr p pu
ax t a tppt us dt druaml iu tr d ctn etfli
!Unit)heater:)A!directX!uatiut acdtrbXmade,!encased!a um lb iclns iu a uatiu ulumuidt ait motor,!
ais s ructtial tndludi
!
Unit)system:)A b dum d ad cai u rumtdus rtm d u n ur’ prum u fl d tnd s ctiiuctiu ru r uuraidX!
ctida i iu pard t fladur ctiiucttit tr ixus ulucdr cal ctiiuctti i
!
Unloader:)A!device!in!a!compressor!for!equalizing!highXand!lowXside!pressures!when!the!compressor!stops!and!
!
tr a r u pur ts afur d dard t a dt sucrua u d u dartiu ltas ti d u mtdtri
!Vacuum:)A!pressure!below!atmospheric,!usually!measured!in!inches!of!mercury!below!atmospheric!
pressure.!
Page 24
!
!
!
Thermocouple:)A sud cu cti tiu t dflt ulucdr cal ctisncdtr ad iu dflt onictti —one!at!a!point!whose!
temperature!is!to!be!measured,!and!the!other!at!a!known!temperature.!The!temperature!between!the!two!
onictti sudurm ius b d u madur al c aracdur tc ais d u ulucdr cal ptduital etup.!
!
Thermodynamics:)The!science!of!the!mechanics!of!heat.!
!!
Thermometer:)A sud cu tr is catiu dumpuradnrui
!
Thermostat:)A!temperatureXactuated!switch.!
!!
Tiu)if)refrigeratiu:)Ru r uuratti uln daluid dt d u multiu t 2 dti t cu pur 3 i 77t555 Bdntsab,!12,000!
Btu/h,!or!200!Btu/min.!
!
Total)heat:)T u dtdal uad assus dt a ru r uuraid a tdu ai ar drarb dartiu pt id dt r iu d dt a u dui ud t
ctis tti n nallb uxpru us i Bdntptnisni Ftr i daicut i a npurXheated!gas,!the!combined!heat!added!to!!!
t!u l ln s iucu arb dt ra u d dumpuradnru rtm ai ar drarb dartiu pt id dt d u uvaporatti dumpuradnru
dt ctmpludu udaptrattit ais dt ra u d u dumpuradnru dt d u iial dumpuradnru fl uru d u ua npur
uadusi
!
Total)pressure:)Ii en s etflt d u nm t datc pru nru ais dultc db pru nrui
!
T)rb)aeu)fliw:)Fln s etfl i fl c d u en s mtdu drai dur ulb a flull a i d u s ructti t d u dn u tr p pu
ax t a tppt us dt druaml iu tr d ctn etfli
!Unit)heater:)A!directX!uatiut acdtrbXmade,!encased!a um lb iclns iu a uatiu ulumuidt ait motor,!
ais s ructtial tndludi
!
Unit)system:)A b dum d ad cai u rumtdus rtm d u n ur’ prum u fl d tnd s ctiiuctiu ru r uuraidX!
ctida i iu pard t fladur ctiiucttit tr ixus ulucdr cal ctiiuctti i
!
Unloader:)A!device!in!a!compressor!for!equalizing!highXand!lowXside!pressures!when!the!compressor!stops!and!
!
tr a r u pur ts afur d dard t a dt sucrua u d u dartiu ltas ti d u mtdtri
!Vacuum:)A!pressure!below!atmospheric,!usually!measured!in!inches!of!mercury!below!atmospheric!
pressure.!
Glossary of HVAC terms
Page 25
!
!
!
Valve:)Ii ru r uurattit a sud cu tr ruunlatti t a l ln st a rt tr ua i
!
Vapor:)A ua t partcnlarlb tiu iuar dt uln l r nm fl d d u l ln s p a u t d u n daicut fl c stu itd tlltfl
the!gas!laws.!Frequently!used!instead!t ua tr a ru r uuraid aist i uuiuralt tr aib ua ultfl d u cr tcal
temperature.!
!
Viscosity:)T u prtpurdb t a en s dt ru d etfl tr c aiuu t apui
!Water)cooler:)daptradtr tr cttl iu fladur i ai is rucd ru r uuratiu b dumi
!!!!
Wax:)A!material!that!may!separate!when!oil/refrigerant!mixtures!are!cooled.!Wax!may!plug!the!expansion!valve!
and!reduce!heat!transfer!of!the!coil.!
!
Wet<bulb)depression:)D uruid udfluui srbX!and!wetXbulb!temperatures.!
!
Wet)compression:)A b dum t ru r uurattit i fl c tmu liquid!refrigerant!is!mixed!with!vapor!entering!the!
compressor!so!as!to!cause!discharge!vapors!from!the!compressor!to!tend!to!be!saturated!rather!than!
superheated.!
!Xylene:)A eamma lu tlduidt m lar dt kurt uiut n us tr s tld iu tr ltt ui iu lnsuu t and!for!cleaning!
compressors!and!lines.!
!Zero,)absolute,)of)pressure:)T u pru nru ux tiu i a du ul d ad uitrulb umpdbi T u ltflu d pt lu
pressure.!Perfect!vacuum.!
!!
Zero,)absolute,)of)temperature:)The!temperature!at!which!a!body!has!no!heat!in!it!(–459.6®F!or!–273.1®C).!
!!
Ziue,)cirfir))aierageu:)T u raiuu t u uctdu dumpuradnru snr iu fl c d u maotr db t asnld uul
!
comfortable.!
Page 25
!
!
!
Valve:)Ii ru r uurattit a sud cu tr ruunlatti t a l ln st a rt tr ua i
!
Vapor:)A ua t partcnlarlb tiu iuar dt uln l r nm fl d d u l ln s p a u t d u n daicut fl c stu itd tlltfl
the!gas!laws.!Frequently!used!instead!t ua tr a ru r uuraid aist i uuiuralt tr aib ua ultfl d u cr tcal
temperature.!
!
Viscosity:)T u prtpurdb t a en s dt ru d etfl tr c aiuu t apui
!Water)cooler:)daptradtr tr cttl iu fladur i ai is rucd ru r uuratiu b dumi
!!!!
Wax:)A!material!that!may!separate!when!oil/refrigerant!mixtures!are!cooled.!Wax!may!plug!the!expansion!valve!
and!reduce!heat!transfer!of!the!coil.!
!
Wet<bulb)depression:)D uruid udfluui srbX!and!wetXbulb!temperatures.!
!
Wet)compression:)A b dum t ru r uurattit i fl c tmu liquid!refrigerant!is!mixed!with!vapor!entering!the!
compressor!so!as!to!cause!discharge!vapors!from!the!compressor!to!tend!to!be!saturated!rather!than!
superheated.!
!Xylene:)A eamma lu tlduidt m lar dt kurt uiut n us tr s tld iu tr ltt ui iu lnsuu t and!for!cleaning!
compressors!and!lines.!
!Zero,)absolute,)of)pressure:)T u pru nru ux tiu i a du ul d ad uitrulb umpdbi T u ltflu d pt lu
pressure.!Perfect!vacuum.!
!!
Zero,)absolute,)of)temperature:)The!temperature!at!which!a!body!has!no!heat!in!it!(–459.6®F!or!–273.1®C).!
!!
Ziue,)cirfir))aierageu:)T u raiuu t u uctdu dumpuradnru snr iu fl c d u maotr db t asnld uul
!
comfortable.!
Glossary of HVAC terms
Page 26
!
!
!!
References:!
!!
Miller,!R!&!Miller,!M.R.!(2006)!Air(Cinditininn((((((RerinRratin.!London:!McGrawXHill.!
!!
Althouse,!A.!&!Turnquist,!C.H.!(2004)!MidRrn(((RerinRratin(and(Ari(Cinditininnn(Illinois:!The!GoodhearXWillcox!
Company.!
!!!!!!
Let’s)Get)Social!)
Twitter/@fatmirhyseni)!
!
!
Page 26
!
!
!!
References:!
!!
Miller,!R!&!Miller,!M.R.!(2006)!Air(Cinditininn((((((RerinRratin.!London:!McGrawXHill.!
!!
Althouse,!A.!&!Turnquist,!C.H.!(2004)!MidRrn(((RerinRratin(and(Ari(Cinditininnn(Illinois:!The!GoodhearXWillcox!
Company.!
!!!!!!
Let’s)Get)Social!)
Twitter/@fatmirhyseni)!
!
!
Download
Download Slideshow Get the original presentation fileQuick Actions
Statistics
- Views 2,826
- Slides 30
- Favorites 3
- Age 3954 days
Related Slideshows
11
8-top-ai-courses-for-customer-support-representatives-in-2025.pptx
JeroenErne2
44 views
10
7-essential-ai-courses-for-call-center-supervisors-in-2025.pptx
JeroenErne2
45 views
13
25-essential-ai-courses-for-user-support-specialists-in-2025.pptx
JeroenErne2
36 views
11
8-essential-ai-courses-for-insurance-customer-service-representatives-in-2025.pptx
JeroenErne2
33 views
21
Know for Certain
DaveSinNM
19 views
17
PPT OPD LES 3ertt4t4tqqqe23e3e3rq2qq232.pptx
novasedanayoga46
23 views