hvacbasicconceptsofac-120509212036-phpapp01.pptx

HVAC Basic

1. Basic Concepts of Air Conditioning Prepared exclusively for COACH LEATHERWARE

2. Panel Moderator: Bob Keingstein Boss Facilities Services 631-361-7430 [email protected]

3. Architect’s Geometry Test

4. SOURCE OF COOL AIR • COIL • HEAT COIL COOL AIR

5. TYPICAL ALL-AIR SYSTEM S.A. DUCT HEAT COIL COOL AIR S.A. FAN

6. TYPICAL ALL-AIR SYSTEM S.A. DUCT HEAT COIL COOL AIR S.A. TERMINAL S.A. FAN

7. TYPICAL ALL-AIR SYSTEM S.A. DUCT HEAT COIL R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN WARM AIR

8. TYPICAL ALL-AIR SYSTEM R.A DUCT S.A. DUCT HEAT COIL R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN

9. TYPICAL ALL-AIR SYSTEM R.A DUCT S.A. DUCT HEAT COIL R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

10. TYPICAL ALL-AIR SYSTEM R.A DUCT S.A. DUCT HEAT R.A. DAMPER COIL FILTER O.A. DAMPER FRESH OUTDOOR AIR R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

11. TYPICAL ALL-AIR SYSTEM R.A DUCT S.A. DUCT HEAT R.A. DAMPER COIL E.A. DAMPER FILTER O.A. DAMPER FRESH OUTDOOR AIR EXHAUST AIR R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

12. Economizer Provides cooling to space when outdoor air temperatures are below 55 degrees Switches over automatically from mechanical cooling Adjusts R.A. and F.A. dampers to maintain space temp May incorporate enthalpy control Mandatory in some states based on unit capacity

13. TYPICAL ALL-AIR SYSTEM R.A DUCT S.A. DUCT CHILLED WATER PUMP HEAT R.A. DAMPER COIL E.A. DAMPER FILTER WATER PIPING WATER CHILLER O.A. DAMPER FRESH OUTDOOR AIR EXHAUST AIR R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

14. TYPICAL ALL-AIR SYSTEM CONDENSER PUMP R.A DUCT S.A. DUCT CHILLED WATER PUMP HEAT R.A. DAMPER COIL E.A. DAMPER FILTER WATER PIPING COOLING TOWER HEAT WATER CHILLER O.A. DAMPER FRESH OUTDOOR AIR EXHAUST AIR R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

15. TYPICAL ALL-AIR SYSTEM CONDENSER PUMP R.A DUCT S.A. DUCT CHILLED WATER PUMP HEAT R.A. DAMPER COIL E.A. DAMPER FILTER WATER PIPING COOLING TOWER HEAT WATER CHILLER BOILER O.A. DAMPER FRESH OUTDOOR AIR EXHAUST AIR R.A. GRILL COOL AIR S.A. TERMINAL S.A. FAN R.A. FAN

16. Equipment Types ROOFTOP PACKAGE UNIT SPLIT SYSTEM CHILLED WATER AIR HANDLER VARIABLE AIR VOLUME (VAV) AIR TO AIR HEAT PUMP Life expectancy 10 to 12 yrs for rooftop and split systems Expect increase in repair costs as equipment ages Typically largest expense to operation of store, energy/repair costs Repair or Replace?

17. Single Package Roof Top Unit Most common Entire hvac system is located on mall roof Most common to have roof leaks from roof curb, condensate overflow or roof punctures

18. Single Package Roof Top Unit CONDR COIL COMP FAN HEAT ELECTRIC HEATER S.A. DUCT S.A. TERMINAL R.A. DUCT O.A. E.A. HEAT

19. Single Package Roof Top Unit Rooftop package unit Mounted on adaptor curb Power exhaust and economizer installed

20. Split System HVAC system split into 2 pieces Condensing unit located on roof (houses compressor, condenser coil, condenser fan motor) Air handler located in space above ceiling (houses blower assembly, evap coil, air filters) Connected electrically and with refrigerant piping Most prone to refrigerant leaks especially if long distance between components Many times refrigerant lines are buried in construction and inaccessible

21. SPLIT SYSTEM COIL HEAT AIR R.A. DUCT O.A. E.A. FAN C O N D R C O M P CONDENSING UNIT REFRIGERANT LINES S.A. DUCT POSSIBLE ELECTRIC HEAT AIR HANDLING UNIT OPTIONAL SUPPLEMENTARY HEATING SYSTEM HEAT

22. SPLIT SYSTEM

23. Split System Air cooled condensing unit Compressor, condenser coil and condenser fans Connected to indoor air handler

24. VAV BOX Consists of VAV terminal box located in the space above ceiling May have supplemental blower motor for positive airflow to space May have air filtration Has a damper inside that opens and closes on demand from thermostat to allow more or less airflow to space Variable Air Volume

25. Major System Components Compressor Condenser coil Evaporator coil Condenser fan motor Evaporator fan motor Thermostatic expansion valve Evaporator blower assembly Economizers (Optional)

26. HEAT REJECTION (“HIGH TEMPERATURE”) 85F       75F 95F 55F 45F CONDITIONED SPACE 105F 95F HEAT GATHERING (“LOW TEMPERATURE”) REFRIGERATION MACHINE (REFRIGERATION CYCLE) 35F COOLING TOWER 95F DB 78F DB HEAT COMPRESSOR COOLER CONDENSER

27. Compressor This component is the heart of the system.. Pumps refrigerant and oil throughout system Separates the high pressure side of the system from the low pressure side If compressor fails, no cooling is possible

28. Condenser Condenser coil is what gets rid of the heat in the system Can be water or air cooled, however most are air cooled in retail application Located outdoors (air cooled) Fins on coil are subject to corrosion in salt water environment. Special coatings can be applied. Fins are subject to damage from hail Traps dirt and requires periodic cleanings

29. Evaporator Coil Provides cold air to the space Located after the system air filters Return air is blown over the coil and chilled Removes moisture from air (condensate) Traps dirt that gets past air filters, reducing cooling capacity (95% is bacterial) Requires periodic chemical cleaning

30. Evaporator Fan Motor Located behind condenser coil Draws ambient air across condenser coil System may have up to 4 or more motors based on system capacity Motors are direct drive with fan blades attached Requires little if any maintenance (sealed bearings)

31. TXV Thermal Expansion Valve Located at the evaporator coil Provides the correct amount of refrigerant to the evaporator coil for proper cooling Separates the high pressure side of the system from the low pressure side Failure could cause compressor failure and loss of system cooling capacity Frequently overlooked in diagnosing system problems Requires manual setting of superheat for proper operation.

32. Evaporator Blower Assembly Consists of: Blower motor Pulleys and fan belts Bearings Fan shaft Fan wheels Housings Can be located indoors or outdoors

33. Control Types CONVENTIONAL THERMOSTAT DIGITAL PROGRAMMABLE THERMOSTAT PNEUMATIC LCD SYSTEM MALL INTERFACE

34. Low Ambient Controls Low ambient controls May be added to air cooled systems that must operate when outdoor temperatures are below 55 degrees Cycles condenser fan/s to maintain correct system pressures Used when economizer is not present Much less costly to install Much more costly to operate

35. Conventional Thermostat Completely manual operation Will maintain a single heat or cool setting System must be switched from heat to cool No energy savings Will allow system to operate all night while store is closed wasting energy Easy to tamper with Least expensive to install

36. Programmable Thermostat Provides auto changeover from heat to cool Provides up to 4 heat/cool settings per 24 hour period Can provide different weekend settings Keyboard can be locked out Set it and forget it

37. Pneumatic Thermostat Uses air provided by mall to operate thermostat Very commonly used with VAV systems Least commonly found in malls Parts are fairly expensive

38. LCD Thermostat Used in newer stores Programmable type Can be dialed into by monitoring company for data

39. WATER PIPING VS. AIR DUCTWORK 5/8” OD – 2.4 GPM @ 6 FPS & 10° RISE = 1 TON OF COOLING 8” RD DUCT 400 CFM @ 1200 FPM OR 5” RD DUCT 400 CFM @ 3000 FPM = 1 TON OF COOLING