An Air conditioning system

APPLICATION OF THERMODYNAMICS TO AN AIR CONDITIONING SYSTEM

1. APPLICATION OF
THERMODYNAMICS TO AN AIR
CONDITIONING SYSTEM
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2. ABSTRACT
•Ever wondered how you get cool breeze from air conditioner. What
mechanism is actually involved in producing cold air in burning hot
summers! No matter what type of air conditioner you are using,
windowed, split wall mounted (PTAC), cabinet floor standing or roof
top type, they still follow the same principle and laws of
thermodynamics.
•In this presentation, we are considering how the first and second laws of
thermodynamics applies to the air conditioning system.

3. INTRODUCTION
•Thermodynamics is a branch of physics concerned with heat and
temperature and their relation to energy and work.
•Thermodynamics applies to a wide variety of topics in science and
engineering, especially physical chemistry, chemical engineering and
mechanical engineering.
•One of the applications of thermodynamics is in the air conditioning
system.
•Air conditioning (often referred to as A/C or AC) is the process of
altering the properties of air (primarily temperature and humidity) to
more comfortable conditions, typically with the aim of distributing the
conditioned air to an occupied space such as a building or a vehicle to
improve thermal comfort and indoor air quality. In common use, an air
conditioner is a device that lowers the air temperature. The cooling is
typically achieved through a refrigeration cycle.

4. THE REFRIGERATION CYCLE IN AN AIR CONDITIONER
–EVAPORATION: Liquid refrigerant at low pressure is brought into
contact with the heat source. The refrigerant absorbs heat and
boils producing a low pressure vapour.
–COMPRESSION: The pressure of the refrigerant vapour is raised
leading to a subsequent increase in temperature of the refrigerant
vapour.
–CONDENSING: The high pressure refrigerant gas now carrying the
heat energy absorbed at the evaporator plus the work energy from
the compressor enters the condenser where the heat transfer will
take place condensing the refrigerant from a high pressure vapour
to a high pressure liquid.
–EXPANSION: The condensed liquid pressure is reduced by a
Metering device(expansion valve) resulting to a low pressure
liquid.

6. DISCUSSION
FIRST LAW OF THERMODYANMICS
•“When a system undergoes a thermodynamic cycle then the net heat supplied to
the system from the surroundings is equal to net work done by the system on its
surroundings”
•
•Or dQ= dW…… Where represents the sum for a complete cycle.
THE SECOND LAW OF THERMODYNAMICS:
CLAUSIUS STATEMENT
•It states that it is impossible for a self acting machine working in a cyclic process
without any external force, to transfer heat from a body at a lower temperature to
a body at a higher temperature.
•It simply states that an Air conditioner cannot operate unless its compressor is
driven by an external power source, such as an electric motor.

7. •The application of The First Law of Thermodynamics which states that When a system
undergoes a thermodynamic cycle then the net heat supplied to the system from the
surroundings which in this instance is the absorption of heat by the refrigerant in the
Air conditioning system is equal to net work done by the entire Air conditioning system
on its surroundings.
•According to The First Law of Thermodynamics all energy must be conserved. Energy
is conserved in a refrigeration system by having both an Evaporator and a Condenser.
•The process of Air conditioning directly follows the Clausius statement of The Second
Law of Thermodynamics where heat is taken in from a cold environment, work is
applied, and heat is expelled to a hot environment. An Air conditioner net effect is to
remove heat from a cold environment, making the environment colder and transferring
the removed heat to a hot environment making the hot environment even “hotter”.

8. CONCLUSION AND RECOMMENDATION
•Thermodynamics, as with most concepts in science and physics, is most accurately
described using mathematical equations such as The First Law of
Thermodynamics.
•An air conditioner has applications that can be categorized into comfort and
process applications as discussed below;
•Comfort applications aim to provide a building indoor environment that remains
relatively constant despite changes in external weather conditions or in internal
heat loads.
• Process applications aim to provide a suitable environment for a process being
carried out, regardless of internal heat and humidity loads and external weather
conditions. It is the needs of the process that determine conditions, not human
preference.

9. For more
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10. For more
•GO TO:
•http://www.geeksterritory.com