1. Technical Seminar on Application and Technical Specification 21 June 2016
Rezza Arif Bin Mustapa Kamal
Senior Engineer
Project And Application Department
CONFIDENTIAL

2. Classification of Air Conditioning System
HVAC Systems
(Heating, Ventilating and Air Conditioning)
Applied Product Systems
(AP)
Unitary Product Systems
(UP)
Chilled Water
Direct Expansion (DX)
Air Cooled
Scroll
Modular
Water Cooled
Absorption
Centrifugal
Screw
Scroll
Air Cooled
Water Cooled
Split
Packaged
Split
Packaged
Single
Multi

3. Classification of Air Conditioning System
Factors affecting the decision to select Unitary or Applied systems include:
Installed Cost
Energy consumption
Space requirements
Freeze prevention
Precision
Building height, size, shape
System cooling and heating capacity
Centralized maintenance
Stability of control
Individual tenant billing

4. What Is Air Conditioning?
Fundamentals of Air-Conditioning
What Is Air Conditioning?

5. What is Air Conditioning?
Fundamentals of Air-Conditioning
What is Air Conditioning?
It is defined as “the process of treating air so as to control simultaneously its
temperature,
humidity,
cleanliness
to meet the requirements of the conditioned space.
& distribution
Humidity
Heat
Dust
Sources of heat : Sensible & Latent heat, examples and explanation
Humidity : Sources of humidity, dehumidification process and humidifying process
Dust : Filtration for different applications
Distribution : Air is used to control these 3 factors. Measures to calculate airflow rates to dilute and remove contaminants. Effect on the temperature gradient. Higher ACH reduces temp difference between return and supply
Distribution
Air Conditioned Space

6. What Is Air Conditioner?
Fundamentals of Air-Conditioning
What Is Air Conditioner?

7. What is Air Conditioner?
Fundamentals of Air-Conditioning
What is Air Conditioner?
Air-conditioners are fundamentally built on the principle of refrigeration cycle which consists mainly the following components :-
Condenser
Let us study in more detail on what these 4 different components do
Compressor
Expansion Device
Evaporator

8. Evaporator (Fan Coil Unit)
Fundamentals of Air-Conditioning
What is the function of the evaporator?
Evaporator (Fan Coil Unit)
Liquid refrigerant changes to gas by absorbing heat from the air, hence, cooling the air as it passes the evaporator.
Most of the liquid refrigerant would have changed to gas by the end of the evaporator coil.
Accumulator functions as a buffer tank to trap liquid refrigerant before entering the compressor.
The evaporator cools the air in the room by evaporating the refrigerant that passes through it. Heat is then removed from the room and is carried away by refrigerant gas ….

9. Fundamentals of Air-Conditioning
With continuous supply of refrigerant to an open system,
it is inefficient and costly.
Ref
Air flow
….. therefore we need a closed system

10. Basic Refrigeration System
Fundamentals of Air-Conditioning
Basic Refrigeration System A B C D
EVAPORATOR
COMPRESSOR
EXPANSION
DEVICE
CONDENSER
High pressure side
Low pressure side
Discharge line
Suction line
Liquid line
Placing each component in its proper sequence within the system, the compressor and expansion device maintain a pressure difference between the high-pressure side of the system (condenser) and the low-pressure side of the system (evaporator).
This pressure difference allows two things to happen simultaneously. The evaporator can be at a pressure and temperature low enough to absorb heat from the air or water to be cooled, and the condenser can be at a temperature high enough to permit heat rejection to ambient air or water that is at normally available temperatures.
Q : Location for High Side, Low Side, Accumulator. TXV Sensing Bulb. Filter Drier. 10

11. Fundamentals of Air-Conditioning
TXV/EXV have capabilities to adjust the flow of the liquid refrigerant into the evaporator based on the sensor bulb temperature
Accumulator, function to trap liquid from evaporator from entering the compressor (highly damaging for rotary compressors)
Hermetic, semi-hermetic compressors, difference between them is the maintenance capabilities
6) Receiver tank, acts as a store to keep refrigerant during pump down operation, usually available inside variable volume system to keep additional refrigerant during low load periods
Note the location of the hi and lo pressure discharge gauges 11

12. Fundamentals of Air-Conditioning
Placing each component in its proper sequence within the system, the compressor and expansion device maintain a pressure difference between the high-pressure side of the system (condenser) and the low-pressure side of the system (evaporator).
This pressure difference allows two things to happen simultaneously. The evaporator can be at a pressure and temperature low enough to absorb heat from the air or water to be cooled, and the condenser can be at a temperature high enough to permit heat rejection to ambient air or water that is at normally available temperatures. 12

13. AIR COOLED CHILLER SYSTEM
Fundamentals of Air-Conditioning
AIR COOLED CHILLER SYSTEM
Expansion device
Evaporator/ Heat Exchanger
Chilled water
Condenser
Water pump P
Names of air conditioning system. First is how the refrigerant is cooled, second is how the room air is cooled.
Draw 3 types of refrigerant cycles. Air/Water cooled and DX/chilled water system
FCU
FCU
Compressor
AHU

14. Water condensate flows down
Fundamentals of Air-Conditioning
Evaporator
Absorb heat from the air that passes thru and transfer to the refrigerant and carried away
Function:
Cool air A
Mixture of liquid and vapor
refrigerant
At the inlet to the evaporator, the refrigerant exists as a cool, low-pressure mixture of liquid and vapor. In this example, the evaporator is a finned-tube coil used to cool air. Other types of evaporators are used to cool water.
The relatively warm air flows across this finned-tube arrangement and the cold refrigerant flows through the tubes. The refrigerant enters the evaporator (A) and absorbs heat from the warmer air, causing the liquid refrigerant to boil. The resulting refrigerant vapor (B) is drawn to the compressor. B
Vapor
refrigerant
Warm air
Water condensate flows down 14

15. Compressor Fundamentals of Air-Conditioning Function:
Refrigerant is being compressed from low pressure & temperature to a pressure & temperature high enough to be condensed
Function: C
High pressure vapor refrigerant to condenser
Low pressure vapor refrigerant from evaporator B
The compressor raises the pressure of the refrigerant vapor from evaporator (B) to a pressure and temperature high enough in the condenser (C) so that it can reject heat to another fluid, such as ambient air or water. There are several types of compressors.
This hot, high-pressure refrigerant vapor then travels to the condenser. The compressor is the “engine” or “heart” of the air-conditioning unit. It pumps the refrigerant allowing it to circulate around the unit. 15

16. Condenser Fundamentals of Air-Conditioning Function:
Heated refrigerant gas from compressor enter the condenser, heat is being rejected to the atmosphere when cooler ambient air pass thru it
Function:
Cool ambient air C
Vapor
refrigerant from compressor
The condenser is a heat exchanger used to reject the heat of the refrigerant to another medium. The example shown is an air-cooled condenser that rejects heat to the ambient air. Other types of condensers are used to reject heat to water.
The hot, high-pressure refrigerant vapor (C) flows through the tubes of this condenser and rejects heat from the cooler ambient air that passes through the condenser coil. As the heat content of the refrigerant vapor is reduced, it condenses into liquid (D).
Heat is rejected from refrigerant. Air flowing out through the coil is HOT.
From the condenser, the high-pressure liquid refrigerant travels to the expansion device. D
Liquid
refrigerant to TXV
Warm air 16

17. Expansion Device (TXV)
Fundamentals of Air-Conditioning
Expansion Device (TXV)
Throttle the refrigerant flow causing sudden drop of high pressure to low pressure where a flash expansion occurs that turns liquid to convert into vapor state
Function:
Mixture of liquid and vapor
refrigerant to evaporator
Liquid
refrigerant from condenser D A
The primary purpose of the expansion device is to drop the pressure of the liquid refrigerant to equal the pressure in the evaporator. Several types of expansion devices can be used. The device shown is an expansion valve.
The high-pressure liquid refrigerant (D) flows through the expansion device, causing a large pressure drop. This pressure drop reduces the refrigerant pressure, and, therefore, it temperature, to that of the evaporator. At the lower pressure, the temperature of the refrigerant is higher than its boiling point. This causes a small portion of the liquid to boil, or flash. Because heat is required to boil this small portion of refrigerant, the boiling refrigerant absorbs heat from the remaining liquid refrigerant, cooling it to the desired evaporator temperature.
The cool mixture of liquid and vapor refrigerant then enters the evaporator (A) to repeat the cycle. 17

18. Fundamentals of Air-Conditioning
Basic Refrigeration Cycle
110°F
[43.3°C]
condenser G E D F
121.5°F
[49.7°C]
expansion
device
compressor
This cool mixture of liquid and vapor refrigerant leaving the expansion device then enters the evaporator (A) to repeat the cycle.
The vapor-compression refrigeration cycle has successfully recovered the refrigerant that boiled in the evaporator and converted it back into a cool liquid to be used again. A B C
51.0°F
[10.6°C]
evaporator
41.0°F
[5.0°C]

19. Fundamentals of Air-Conditioning
Refrigeration Cycle – R410A
condenser G E D
psig F
expansion
device
pressure
compressor
This cool mixture of liquid and vapor refrigerant leaving the expansion device then enters the evaporator (A) to repeat the cycle.
The vapor-compression refrigeration cycle has successfully recovered the refrigerant that boiled in the evaporator and converted it back into a cool liquid to be used again.
Which region denotes the below data;
Compressor power input
Cooling Capacity
Condenser Capacity
Superheat
Subcool
psig A B C
evaporator
enthalpy

20. Two types of heat Basics of Heat Load Calculation Sensible Heat
Addition of Heat = change in temperature

21. Two types of heat Basics of Heat Load Calculation Latent Heat
Addition of Heat = change in state

22. Classification of cooling load
Basics of Heat Load Calculation
Classification of cooling load
Load components can be classified into 3 categories:
1) Skin Load
2) Internal Load
3) Other Load

23. Skin load for a space Basics of Heat Load Calculation Ceiling & Roof /
Upper Rooms
Ventilation
Partitions /
Inner Walls
Glass
Infiltration
Wall
Ground /
Lower Rooms

24. Internal Load for space
Basics of Heat Load Calculation
Internal Load for space
Lights
Lights
People
Equipment/
Appliances

25. Other load for space Basics of Heat Load Calculation Duct Leakage
Heat Gain
Heat Gain
Fan Heat

26. heat load components in a space
Basics of Heat Load Calculation
heat load components in a space

27. Heat Load Calculation

28. Equivalent Temperature difference method
Basics of Heat Load Calculation
Equivalent Temperature difference method
Heat Gain is given by:
Q = Rate of heat transfer [W]
A = Area of surface [m2]
U = Thermal transmittance [ W/m2 K]
ΔT = Temperature difference of wall surface(To – Ti)
Q = A x U x ΔT

29. Equivalent Temperature difference method
Basics of Heat Load Calculation
Equivalent Temperature difference method
External Walls
Internal Walls
Roofs
Q = A x U x ΔT
Can be used to measure heat load for:
Floors
Glass
Partitions
Ceilings
Note: This equation is used to calculate ONLY transmission gain

30. Formula for u- value calculation
Basics of Heat Load Calculation
Formula for u- value calculation

31. Formula for u- value calculation
Basics of Heat Load Calculation
Formula for u- value calculation

32. Example U-value calculation
115mm Brick wall + Finishes (Both Sides) 12mm thick cement plaster
Components
b/K
R [m2 K/W]
Density [kg/m3]
Weight [kg/m2]
Outside air film --
12mm cement plaster
115mm brick wall
Indoor air film
Total R:
Total Weight:
0.120
0.012/0.533
0.023
1568
18.82
0.115/0.807
0.143
1760
202.4
0.023
0.012/0.533
1568
18.82
0.044
0.352
240.04
U = 1/R = 1/0.352 = W/m2 K

33. Basics of Heat Load Calculation
Solar Gain - Glass
Solar gain is given by:
Q = Rate of heat transfer [W]
A = Area of glass [m2]
SF = Solar Factor [W/m2]
Sc = Shading coefficient of glass window
Q = A x SF x Sc

34. Solar factor selection
Reference Glass is 3 mm thick ordinary glass set in aluminium frame

35. Shading coefficient selection
External Shading Devices:
1) Horizontal Projection
2) vertical Projection
3) Egg-crate Lourves

36. Infiltration load Qi = Qis + Qil Infiltration load is given by:
Qi = Infiltration heat load [W]
Qis= Sensible infiltration heat gain [W]
Qil= Latent infiltration heat gain [W]
v = Infiltration air volume [m3/h]
ΔT= Temperature difference of outdoor and indoor air
ΔX= Absolute humidity difference of outdoor and indoor air
Qi = Qis + Qil
Qis = 0.33 x v x ΔT
Qil = 833 x v x ΔX

37. Cooling load calculation
Basics of Heat Load Calculation
Cooling load calculation
Summing up all of the heat load components:
Skin Load
Wall, glass, floor, roof and ceiling transmission heat gain
Glass solar heat gain
Infiltration heat gain
Internal Load
People heat
Appliances
Lighting
Other Load
Duct leakage
Heat Gain

38. Heat load calculation form

39. Heat load calculation form

40. Heat load calculation form

41. Heat load calculation form

42. Heat load calculation form
Tables for heat load calculation

43. Heat load calculation form
Tables for heat load calculation

44. Tables for heat load calculation
Heat load calculation form
Tables for heat load calculation

45. Rule of thumb

46. QUESTIONS?