refrigeration and air conditioning

227
1 Training Session on Refrigeration Training Session on Refrigeration & Air Conditioning & Air Conditioning Refrigeration & Air Refrigeration & Air Conditioning Conditioning Presentation by “Mohammad Salim” M/s Unitech Ltd., Gurgaon.

Upload: bnacharya

Post on 18-Jan-2016

41 views

Category:

Documents


1 download

DESCRIPTION

Detail of RAC for HVAC system

TRANSCRIPT

Page 1: Refrigeration and Air Conditioning

1

Training Session on Refrigeration Training Session on Refrigeration & Air Conditioning& Air Conditioning

Refrigeration & Air Refrigeration & Air ConditioningConditioning

Presentation by

“Mohammad Salim”

M/s Unitech Ltd., Gurgaon.

Page 2: Refrigeration and Air Conditioning

2

Training Agenda: Refrigeration & Training Agenda: Refrigeration & Air ConditioningAir Conditioning

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 3: Refrigeration and Air Conditioning

3

IntroductionIntroduction

How does it work?

High Temperature Reservoir

Low Temperature Reservoir

R Work Input

Heat Absorbed

Heat Rejected

Page 4: Refrigeration and Air Conditioning

4

IntroductionIntroduction

Thermal energy moves from left to right through five loops of heat transfer:

How does it work?

(Bureau of Energy Efficiency, 2004)

1)

Indoor air loop

2)

Chilled water loop

3)

Refrigerant loop

4)

Condenser water loop

5)

Cooling water loop

Page 5: Refrigeration and Air Conditioning

5

IntroductionIntroduction

AC options / combinations:

AC Systems

• Air Conditioning (for comfort / machine)

• Split air conditioners

• VRV System in Group Housing etc.

• Fan coil units in a larger system

• Air handling units in a larger system

• Evaporating Cooling in a larger system

Page 6: Refrigeration and Air Conditioning

6

IntroductionIntroduction

• Small capacity modular units of direct expansion type (50 Tons of Refrigeration)

• Centralized chilled water plants with chilled water as a secondary coolant (50 – 250 TR)

• Brine plants with brines as lower temperature, secondary coolant (>250 TR)

Refrigeration systems for industrial processes

Page 7: Refrigeration and Air Conditioning

7

IntroductionIntroduction

• Bank of units off-site with common

• Chilled water pumps

• Condenser water pumps

• Cooling towers

• More levels of refrigeration/AC, e.g.

• Comfort air conditioning (20-25 oC)

• Chilled water system (8 – 10 oC)

• Brine system (< 0 oC)

Refrigeration at large companies

Page 8: Refrigeration and Air Conditioning

8

Reference Handbooks/Standards

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 9: Refrigeration and Air Conditioning

9

Reference Handbooks/Standards

ASHRAE Handbook of FundamentalsASHRAE Handbook of Refrigeration ASHRAE Handbook of Application ASHRAE Handbook of System & Equipments ASHRAE Standards 62.1 ASHRAE Standards 90.1 ISHRAE Weather Data Carrier Handbook NBC-2005 LEED-2009 NFPA-92A ECBC-2007 Heat and Mass Transfer SMACNA Standard Indian Standards

Page 10: Refrigeration and Air Conditioning

10

Types of RefrigerationTypes of Refrigeration

Introduction

Reference Handbooks/Standards

Types of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 11: Refrigeration and Air Conditioning

11

Types of RefrigerationTypes of Refrigeration

• Vapour Compression Refrigeration (VCR): uses mechanical energy

• Vapour Absorption Refrigeration (VAR): uses thermal energy

Refrigeration systems

Page 12: Refrigeration and Air Conditioning

12

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

• Highly compressed fluids tend to get colder when allowed to expand

• If pressure high enough

• Compressed air hotter than source of cooling

• Expanded gas cooler than desired cold temperature

Page 13: Refrigeration and Air Conditioning

13

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Two advantages

• Lot of heat can be removed (lot of thermal energy to change liquid to vapour)

• Heat transfer rate remains high (temperature of working fluid much lower than what is being cooled)

Page 14: Refrigeration and Air Conditioning

14

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Page 15: Refrigeration and Air Conditioning

15

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

Low pressure liquid refrigerant in evaporator absorbs heat and changes to a gas

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Page 16: Refrigeration and Air Conditioning

16

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

The superheated vapour enters the compressor where its pressure is raised

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Page 17: Refrigeration and Air Conditioning

17

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

The high pressure superheated gas is cooled in several stages in the condenser

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Page 18: Refrigeration and Air Conditioning

18

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

Liquid passes through expansion device, which reduces its pressure and controls the flow into the evaporator

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Page 19: Refrigeration and Air Conditioning

19

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Type of refrigerant

• Refrigerant determined by the required cooling temperature

• Chlorinated fluorocarbons (CFCs) or freons: R-11, R-12, R-21, R-22 and R-502

Page 20: Refrigeration and Air Conditioning

20

Types of RefrigerationTypes of Refrigeration

Vapour Compression Refrigeration

Choice of compressor, design of condenser, evaporator determined by

• Refrigerant

• Required cooling

• Load

• Ease of maintenance

• Physical space requirements

• Availability of utilities (water, power)

Page 21: Refrigeration and Air Conditioning

21

Types of RefrigerationTypes of Refrigeration

Vapour Absorption Refrigeration

Condenser Generator

Evaporator

AbsorberCold Side

Hot Side

Page 22: Refrigeration and Air Conditioning

22

Types of RefrigerationTypes of Refrigeration

Vapour Absorption Refrigeration

Page 23: Refrigeration and Air Conditioning

23

Types of RefrigerationTypes of Refrigeration

Vapour Absorption Refrigeration

Page 24: Refrigeration and Air Conditioning

24

Types of RefrigerationTypes of Refrigeration

Page 25: Refrigeration and Air Conditioning

25

Types of RefrigerationTypes of Refrigeration

Vapour Absorption Refrigeration

Page 26: Refrigeration and Air Conditioning

26

Types of RefrigerationTypes of Refrigeration

Refrigerant-absorbent combinations for VARS

The desirable properties of refrigerant-absorbent mixtures for VARS are: i The refrigerant should exhibit high solubility with solution in the absorber. This is to say that it should exhibit negative deviation from Raoult’s law at absorber.

ii. There should be large difference in the boiling points of refrigerant and absorbent (greater than 200oC), so that only refrigerant is boiled-off in the generator. This

ensures that only pure refrigerant circulates through refrigerant circuit (condenser-expansion valve-evaporator) leading to isothermal heat transfer in evaporator and condenser.

Page 27: Refrigeration and Air Conditioning

27

Types of RefrigerationTypes of Refrigeration

iii. It should exhibit small heat of mixing so that a high COP can be achieved. However, this requirement contradicts the first requirement. Hence, in practice a trade-off is required between solubility and heat of mixing.

iv. The refrigerant-absorbent mixture should have high thermal conductivity and low viscosity for high performance.

v. It should not undergo crystallization or solidification inside the system.

vi. The mixture should be safe, chemically stable, non-corrosive, inexpensive and should be available easily.

Page 28: Refrigeration and Air Conditioning

28

Types of RefrigerationTypes of Refrigeration

The most commonly used refrigerant-absorbent pairs in commercial systems are: 1. Water-Lithium Bromide (H2O-LiBr) system for above 0oC applications such as air conditioning. Here water is the refrigerant and lithium bromide is the absorbent. 2. Ammonia-Water (NH3-H2O) system for refrigeration applications with ammonia as refrigerant and water as absorbent. Of late efforts are being made to develop other refrigerant-absorbent systems using both natural and synthetic refrigerants to overcome some of the limitations of (H2O-LiBr) and (NH3-H2 O) systems. Currently, large water-lithium bromide (H2O-LiBr) systems are extensively used in air conditioning applications, where as large ammonia-water (NH3-H2O) systems are used in refrigeration applications, while small ammonia-water systems with a third inert gas are used in a pumpless form in small domestic refrigerators (triple fluid vapour absorption systems).

Page 29: Refrigeration and Air Conditioning

29

Types of RefrigerationTypes of Refrigeration

Evaporative Cooling

(Adapted from Munters, 2001)

Cold Air

Hot Air

Sprinkling Water

• Air in contact with water to cool it close to ‘wet bulb temperature’

• Advantage: efficient cooling at low cost

• Disadvantage: air is rich in moisture

Page 30: Refrigeration and Air Conditioning

30

Applied PsychrometricApplied Psychrometric

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 31: Refrigeration and Air Conditioning

31

Applied PsychrometricApplied Psychrometric

Page 32: Refrigeration and Air Conditioning

32

Applied PsychrometricApplied Psychrometric

Page 33: Refrigeration and Air Conditioning

33

Applied PsychrometricApplied Psychrometric

Page 34: Refrigeration and Air Conditioning

34

Applied PsychrometricApplied Psychrometric

Page 35: Refrigeration and Air Conditioning

35

Applied PsychrometricApplied Psychrometric

Page 36: Refrigeration and Air Conditioning

36

Applied PsychrometricApplied Psychrometric

Page 37: Refrigeration and Air Conditioning

37

Applied PsychrometricApplied Psychrometric

Page 38: Refrigeration and Air Conditioning

38

Applied PsychrometricApplied Psychrometric

Page 39: Refrigeration and Air Conditioning

39

Applied PsychrometricApplied Psychrometric

Page 40: Refrigeration and Air Conditioning

40

Applied PsychrometricApplied Psychrometric

Page 41: Refrigeration and Air Conditioning

41

Applied PsychrometricApplied Psychrometric

Page 42: Refrigeration and Air Conditioning

42

Applied PsychrometricApplied Psychrometric

Page 43: Refrigeration and Air Conditioning

43

Applied PsychrometricApplied Psychrometric

Page 44: Refrigeration and Air Conditioning

44

Applied PsychrometricApplied Psychrometric

Page 45: Refrigeration and Air Conditioning

45

Applied PsychrometricApplied Psychrometric

Page 46: Refrigeration and Air Conditioning

46

Applied PsychrometricApplied Psychrometric

Page 47: Refrigeration and Air Conditioning

47

Applied PsychrometricApplied Psychrometric

Page 48: Refrigeration and Air Conditioning

48

Applied PsychrometricApplied Psychrometric

Page 49: Refrigeration and Air Conditioning

49

Applied PsychrometricApplied Psychrometric

Page 50: Refrigeration and Air Conditioning

50

Applied PsychrometricApplied Psychrometric

Page 51: Refrigeration and Air Conditioning

51

Applied PsychrometricApplied Psychrometric

Page 52: Refrigeration and Air Conditioning

52

Applied PsychrometricApplied Psychrometric

Page 53: Refrigeration and Air Conditioning

53

Applied PsychrometricApplied Psychrometric

Page 54: Refrigeration and Air Conditioning

54

Applied PsychrometricApplied Psychrometric

Page 55: Refrigeration and Air Conditioning

55

Applied PsychrometricApplied Psychrometric

Page 56: Refrigeration and Air Conditioning

56

Applied PsychrometricApplied Psychrometric

Page 57: Refrigeration and Air Conditioning

57

Applied PsychrometricApplied Psychrometric

Page 58: Refrigeration and Air Conditioning

58

Applied PsychrometricApplied Psychrometric

Page 59: Refrigeration and Air Conditioning

59

Applied PsychrometricApplied Psychrometric

Page 60: Refrigeration and Air Conditioning

60

Applied PsychrometricApplied Psychrometric

Page 61: Refrigeration and Air Conditioning

61

Applied PsychrometricApplied Psychrometric

Page 62: Refrigeration and Air Conditioning

62

Applied PsychrometricApplied Psychrometric

Page 63: Refrigeration and Air Conditioning

63

Applied PsychrometricApplied Psychrometric

Page 64: Refrigeration and Air Conditioning

64

Heat Load CalculationHeat Load Calculation

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 65: Refrigeration and Air Conditioning

65

Heat Load CalculationHeat Load Calculation

Page 66: Refrigeration and Air Conditioning

66

Heat Load CalculationHeat Load Calculation

Page 67: Refrigeration and Air Conditioning

67

Heat Load CalculationHeat Load Calculation

Page 68: Refrigeration and Air Conditioning

68

Heat Load CalculationHeat Load Calculation

Page 69: Refrigeration and Air Conditioning

69

Heat Load CalculationHeat Load Calculation

Page 70: Refrigeration and Air Conditioning

70

Heat Load CalculationHeat Load Calculation

Page 71: Refrigeration and Air Conditioning

71

Heat Load CalculationHeat Load Calculation

Page 72: Refrigeration and Air Conditioning

72

Heat Load CalculationHeat Load Calculation

Page 73: Refrigeration and Air Conditioning

73

Heat Load CalculationHeat Load Calculation

Page 74: Refrigeration and Air Conditioning

74

Heat Load CalculationHeat Load Calculation

Page 75: Refrigeration and Air Conditioning

75

Heat Load CalculationHeat Load Calculation

Page 76: Refrigeration and Air Conditioning

76

Heat Load CalculationHeat Load Calculation

Page 77: Refrigeration and Air Conditioning

77

Heat Load CalculationHeat Load Calculation

Page 78: Refrigeration and Air Conditioning

78

Heat Load CalculationHeat Load Calculation

Page 79: Refrigeration and Air Conditioning

79

Heat Load CalculationHeat Load Calculation

Page 80: Refrigeration and Air Conditioning

80

Heat Load CalculationHeat Load Calculation

Page 81: Refrigeration and Air Conditioning

81

Heat Load CalculationHeat Load Calculation

Page 82: Refrigeration and Air Conditioning

82

Heat Load CalculationHeat Load Calculation

Page 83: Refrigeration and Air Conditioning

83

Heat Load CalculationHeat Load Calculation

Page 84: Refrigeration and Air Conditioning

84

Heat Load CalculationHeat Load Calculation

Page 85: Refrigeration and Air Conditioning

85

Heat Load CalculationHeat Load Calculation

Page 86: Refrigeration and Air Conditioning

86

Air Duct DesignAir Duct Design

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 87: Refrigeration and Air Conditioning

87

Air Duct DesignAir Duct Design

Page 88: Refrigeration and Air Conditioning

88

Air Duct DesignAir Duct Design

Page 89: Refrigeration and Air Conditioning

89

Air Duct DesignAir Duct Design

Page 90: Refrigeration and Air Conditioning

90

Air Duct DesignAir Duct Design

Page 91: Refrigeration and Air Conditioning

91

Air Duct DesignAir Duct Design

Page 92: Refrigeration and Air Conditioning

92

Air Duct DesignAir Duct Design

TABLE 7 – RECOMMENDED MAXIMUM DUCT VELOCITIES FOR LOW VELOCITY SYSTEMS (FPM)

Page 93: Refrigeration and Air Conditioning

93

Air Duct DesignAir Duct Design

Page 94: Refrigeration and Air Conditioning

94

Air Duct DesignAir Duct Design

Page 95: Refrigeration and Air Conditioning

95

Air Duct DesignAir Duct Design

Page 96: Refrigeration and Air Conditioning

96

Air Duct DesignAir Duct Design

Page 97: Refrigeration and Air Conditioning

97

Air Duct DesignAir Duct Design

Page 98: Refrigeration and Air Conditioning

98

Air Duct DesignAir Duct Design

Page 99: Refrigeration and Air Conditioning

99

Air Duct DesignAir Duct Design

Methods of Duct Design

1- Equal friction Method

2- Static Regain Method

1-Equal Friction Method

This method of sizing is used for supply, exhaust andreturn air duct systems and employs the same friction lollper foot of length for the entire system. The equal frictionmethod is superior to velocity reduction since it requiresless balancing for symmetrical layouts. If a design has a

Page 100: Refrigeration and Air Conditioning

100

Air Duct DesignAir Duct Design

mixture of short and long runs, the shortest run requires considerable dampering. Such a system is difficult to balance since the equal friction method makes no provision for equalizing pressure drops in branches of for providing the same static pressure behind each air terminal.

Page 101: Refrigeration and Air Conditioning

101

Air Duct DesignAir Duct Design

Example 4 – Equal Friction Method of Designing DuctsGiven:Duct systems for general office (Fig.47).Total air quantity – 5400 cfm18 air terminals – 300 cfm eachOperating pressure forall terminals – 0.15 in. wgRadius elbows, R/D = 1.25Find:1.Initial duct velocity, area, size and friction rate in the duct section from the fan to the first branch.2.Size of remaining duct runs.3. Total equivalent length of duct run with highest resistance.4. Total static pressure required at fan discharge

Page 102: Refrigeration and Air Conditioning

102

Air Duct DesignAir Duct Design

2-Static Regain Method

The basic principle of the static regain method is tosize a duct run so that the increase in static pressure(regain due to reduction in velocity) at each branch or airterminal just offsets the friction loss in the succeedingsection of duct. The static pressure is then the samebefore each terminal and at each branch.The following procedure is used to design a ductsystem by this method: select a starting velocity at the fandischarge from Table 7 and size the initial duct sectionfrom Table 6.

Page 103: Refrigeration and Air Conditioning

103

Air Duct DesignAir Duct Design

The remaining sections of duct are sized from Chart10 (L!Q Ratio) and Chart 11 (Low Velocity Static Regain).Chart 10 is used to determine the L/Q ratio knowing theair quantity (Q) and length (L) between outlets orbranches in the duct section to be sized by static regain.This length (L) is the equivalent length between theoutlets or branches, including elbows, excepttransformations. The effect of the transformation section isaccounted for in “Chart 11 3 Static Regain.” Thisassumes that the transformation section is laid outaccording to the recommendation presented in thischapter.

Page 104: Refrigeration and Air Conditioning

104

Air Duct DesignAir Duct Design

Page 105: Refrigeration and Air Conditioning

105

Pressurization SystemPressurization System

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 106: Refrigeration and Air Conditioning

106

Pressurization SystemPressurization System

STAIRCASE PRESSURIZATION CALCULATION FOR BASEMENT PART - A BASEMENT TO GROUND FLOOR)

Q1 = Kf A √ Δ P

Q1 = Air Leakage in Cu. M./ Sec.

A = Area of Leakage in Sq.M.

Δ P = Pressure Difference in Pascal ( 50 Pa)

Kf = Coefficient 0.839

No. of Floors = Basement to Ground Floor = 2

No. of Doors = 2

Door Size = 1.2 M x 2.1 M

Gap Between door and Frame/Floor = 6 mm at Top and on side

= 15 mm at Bottom

Area of Leakage Between Door & Frame

= 2 x H x gap (side) + 1 x W x gap (Top) + 1 x W x gap (Bottom )

= 2 x 2.1 x 6/1000 + 1 x 1.2 x 6/1000 + 1 x 1.2 x 15/1000

= 0.0252 + 0.0072 + 0.018

= 0.0504 Sq. M.

Page 107: Refrigeration and Air Conditioning

107

Pressurization SystemPressurization System

Area of Leakage in Closed Condition/Door = 0.0504 Sq. M.

Total Leakage Area for 2 No. Doors = 0.0504 x 2

= 0.10 Sq.M.

Q1 = 0.839 x 0.10 x √ 50

= 0.60 Cu. M/Sec.

= 1270 CFM

Leakage of Air Thru 2 No. Open Door ( 1 No. at affected floor + 1 No. at Exit to Building )

Q2 = Area of Doors x Velocity

= 2.1 x 1.2 x2 No. x 1.0 M/sec.

= 5.04 Cu. M./Sec

= 10671 CFM

Total Required Air Quantity = Q1 + Q2

= 1270 + 10671

= 11941 CFM

Page 108: Refrigeration and Air Conditioning

108

Pressurization SystemPressurization System

LIFT WELL PRESSURIZATION CALCULATION

TOWER T1 (G+13)- 5 Nos.

Q = Kf A √ Δ P

Q = Air Leakage in Cu. M./ Sec.

A = Area of Leakage in Sq.M.

Δ P = Pressure Difference in Pascal ( 50 Pa)

Kf = Coefficient 0.839

No. of Floors = Lower Basement (Part-A) to 13th Floor = 16

No. of Doors = 16

Door Size = 2.1 M x 1.2 M

Area of Leakage Between Lift Door & Wall/ Door = 0.065 Sq. M.

Total Leakage Area for 16 No. Doors = 0.065 x 16

= 1.04 Sq.M.

Q = 0.839 x 1.04 x √ 50

= 6.17 Cu. M/Sec.

= 13063 CFM

Fan Capacity for Two Lift Well = 13063x2

= 26126 CFM

Say = 26500 CFM

1 No. 26500 CFM DIDW Centrifugal Fan Section For Fresh Air Supply

Page 109: Refrigeration and Air Conditioning

109

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 110: Refrigeration and Air Conditioning

110

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 111: Refrigeration and Air Conditioning

111

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 112: Refrigeration and Air Conditioning

112

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 113: Refrigeration and Air Conditioning

113

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 114: Refrigeration and Air Conditioning

114

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 115: Refrigeration and Air Conditioning

115

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 116: Refrigeration and Air Conditioning

116

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 117: Refrigeration and Air Conditioning

117

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 118: Refrigeration and Air Conditioning

118

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 119: Refrigeration and Air Conditioning

119

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 120: Refrigeration and Air Conditioning

120

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 121: Refrigeration and Air Conditioning

121

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 122: Refrigeration and Air Conditioning

122

Chilled/Condenser Water Piping Chilled/Condenser Water Piping DesignDesign

Page 123: Refrigeration and Air Conditioning

123

CompressorsCompressors

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 124: Refrigeration and Air Conditioning

124

CompressorsCompressors

Page 125: Refrigeration and Air Conditioning

125

CompressorsCompressors

Page 126: Refrigeration and Air Conditioning

126

CompressorsCompressors

Page 127: Refrigeration and Air Conditioning

127

CompressorsCompressors

Page 128: Refrigeration and Air Conditioning

128

CompressorsCompressors

Page 129: Refrigeration and Air Conditioning

129

CompressorsCompressors

Page 130: Refrigeration and Air Conditioning

130

CompressorsCompressors

Page 131: Refrigeration and Air Conditioning

131

CompressorsCompressors

Page 132: Refrigeration and Air Conditioning

132

CompressorsCompressors

Page 133: Refrigeration and Air Conditioning

133

CompressorsCompressors

Page 134: Refrigeration and Air Conditioning

134

CompressorsCompressors

Page 135: Refrigeration and Air Conditioning

135

CompressorsCompressors

Page 136: Refrigeration and Air Conditioning

136

Condensers & EvaporatorsCondensers & Evaporators

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 137: Refrigeration and Air Conditioning

137

Condensers & EvaporatorsCondensers & Evaporators

Page 138: Refrigeration and Air Conditioning

138

Condensers & EvaporatorsCondensers & Evaporators

Page 139: Refrigeration and Air Conditioning

139

Condensers & EvaporatorsCondensers & Evaporators

Page 140: Refrigeration and Air Conditioning

140

Condensers & EvaporatorsCondensers & Evaporators

Page 141: Refrigeration and Air Conditioning

141

Condensers & EvaporatorsCondensers & Evaporators

Page 142: Refrigeration and Air Conditioning

142

Condensers & EvaporatorsCondensers & Evaporators

Page 143: Refrigeration and Air Conditioning

143

Condensers & EvaporatorsCondensers & Evaporators

Page 144: Refrigeration and Air Conditioning

144

Condensers & EvaporatorsCondensers & Evaporators

Page 145: Refrigeration and Air Conditioning

145

Condensers & EvaporatorsCondensers & Evaporators

Page 146: Refrigeration and Air Conditioning

146

Condensers & EvaporatorsCondensers & Evaporators

Page 147: Refrigeration and Air Conditioning

147

Condensers & EvaporatorsCondensers & Evaporators

Page 148: Refrigeration and Air Conditioning

148

Condensers & EvaporatorsCondensers & Evaporators

Page 149: Refrigeration and Air Conditioning

149

Condensers & EvaporatorsCondensers & Evaporators

Page 150: Refrigeration and Air Conditioning

150

Condensers & EvaporatorsCondensers & Evaporators

Page 151: Refrigeration and Air Conditioning

151

Condensers & EvaporatorsCondensers & Evaporators

Page 152: Refrigeration and Air Conditioning

152

Condensers & EvaporatorsCondensers & Evaporators

Page 153: Refrigeration and Air Conditioning

153

Condensers & EvaporatorsCondensers & Evaporators

Page 154: Refrigeration and Air Conditioning

154

Condensers & EvaporatorsCondensers & Evaporators

Page 155: Refrigeration and Air Conditioning

155

Condensers & EvaporatorsCondensers & Evaporators

Page 156: Refrigeration and Air Conditioning

156

Condensers & EvaporatorsCondensers & Evaporators

Page 157: Refrigeration and Air Conditioning

157

Condensers & EvaporatorsCondensers & Evaporators

Page 158: Refrigeration and Air Conditioning

158

Condensers & EvaporatorsCondensers & Evaporators

Page 159: Refrigeration and Air Conditioning

159

Condensers & EvaporatorsCondensers & Evaporators

Page 160: Refrigeration and Air Conditioning

160

Condensers & EvaporatorsCondensers & Evaporators

Page 161: Refrigeration and Air Conditioning

161

Condensers & EvaporatorsCondensers & Evaporators

Page 162: Refrigeration and Air Conditioning

162

Expansion DevicesExpansion Devices

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of refrigeration and AC

Energy efficiency opportunities

Page 163: Refrigeration and Air Conditioning

163

Expansion DevicesExpansion Devices

Page 164: Refrigeration and Air Conditioning

164

Expansion DevicesExpansion Devices

Page 165: Refrigeration and Air Conditioning

165

Expansion DevicesExpansion Devices

Page 166: Refrigeration and Air Conditioning

166

Expansion DevicesExpansion Devices

Page 167: Refrigeration and Air Conditioning

167

Expansion DevicesExpansion Devices

Page 168: Refrigeration and Air Conditioning

168

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of Refrigeration and AC

Energy efficiency opportunities

Cooling TowerCooling Tower

Page 169: Refrigeration and Air Conditioning

169

Cooling TowerCooling Tower

Page 170: Refrigeration and Air Conditioning

170

Cooling TowerCooling Tower

Page 171: Refrigeration and Air Conditioning

171

Cooling TowerCooling Tower

Page 172: Refrigeration and Air Conditioning

172

Cooling TowerCooling Tower

Page 173: Refrigeration and Air Conditioning

173

Cooling TowerCooling Tower

Page 174: Refrigeration and Air Conditioning

174

Cooling TowerCooling Tower

Page 175: Refrigeration and Air Conditioning

175

Cooling TowerCooling Tower

Page 176: Refrigeration and Air Conditioning

176

Cooling TowerCooling Tower

Page 177: Refrigeration and Air Conditioning

177

Cooling TowerCooling Tower

Page 178: Refrigeration and Air Conditioning

178

Cooling TowerCooling Tower

Page 179: Refrigeration and Air Conditioning

179

Cooling TowerCooling Tower

Page 180: Refrigeration and Air Conditioning

180

Cooling TowerCooling Tower

Page 181: Refrigeration and Air Conditioning

181

Cooling TowerCooling Tower

Page 182: Refrigeration and Air Conditioning

182

Cooling TowerCooling Tower

Page 183: Refrigeration and Air Conditioning

183

Cooling TowerCooling Tower

Page 184: Refrigeration and Air Conditioning

184

Cooling TowerCooling Tower

Page 185: Refrigeration and Air Conditioning

185

Cooling TowerCooling Tower

Page 186: Refrigeration and Air Conditioning

186

Cooling TowerCooling Tower

Page 187: Refrigeration and Air Conditioning

187

Cooling TowerCooling Tower

Page 188: Refrigeration and Air Conditioning

188

Cooling TowerCooling Tower

Page 189: Refrigeration and Air Conditioning

189

Cooling TowerCooling Tower

Page 190: Refrigeration and Air Conditioning

190

Cooling TowerCooling Tower

Page 191: Refrigeration and Air Conditioning

191

Cooling TowerCooling Tower

Page 192: Refrigeration and Air Conditioning

192

Cooling TowerCooling Tower

Page 193: Refrigeration and Air Conditioning

193

Cooling TowerCooling Tower

Page 194: Refrigeration and Air Conditioning

194

Cooling TowerCooling Tower

Page 195: Refrigeration and Air Conditioning

195

Cooling TowerCooling Tower

Page 196: Refrigeration and Air Conditioning

196

Cooling TowerCooling Tower

Page 197: Refrigeration and Air Conditioning

197

Cooling TowerCooling Tower

Page 198: Refrigeration and Air Conditioning

198

Cooling TowerCooling Tower

Page 199: Refrigeration and Air Conditioning

199

Cooling TowerCooling Tower

Page 200: Refrigeration and Air Conditioning

200

Cooling TowerCooling Tower

Page 201: Refrigeration and Air Conditioning

201

Cooling TowerCooling Tower

Page 202: Refrigeration and Air Conditioning

202

Cooling TowerCooling Tower

Page 203: Refrigeration and Air Conditioning

203

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of Refrigeration and AC

Energy efficiency opportunities

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Page 204: Refrigeration and Air Conditioning

204

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

• Cooling effect: Tons of Refrigeration

• TR is assessed as:

Assessment of Refrigeration

1 TR = 3024 kCal/hr heat rejected

TR = Q x⋅Cp x⋅ (Ti – To) / 3024

Q = mass flow rate of coolant in kg/hr Cp = is coolant specific heat in kCal /kg deg C Ti = inlet, temperature of coolant to evaporator (chiller) in 0C To = outlet temperature of coolant from evaporator (chiller) in 0C

Page 205: Refrigeration and Air Conditioning

205

Specific Power Consumption (kW/TR)

• Indicator of refrigeration system’s performance

• kW/TR of centralized chilled water system is sum of• Compressor kW/TR

• Chilled water pump kW/TR

• Condenser water pump kW/TR

• Cooling tower fan kW/TR

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Assessment of Refrigeration

Page 206: Refrigeration and Air Conditioning

206

Coefficient of Performance (COPCarnot)

• Standard measure of refrigeration efficiency

• Depends on evaporator temperature Te and condensing temperature Tc:

• COP in industry calculated for type of compressor:

COPCarnot = Te / (Tc - Te)

Cooling effect (kW)COP =

Power input to compressor (kW)

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Assessment of Refrigeration

Page 207: Refrigeration and Air Conditioning

207

COP increases with rising evaporator temperature

(Te)

COP increases with decreasing condensing

temperature (Tc)

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Assessment of Refrigeration

Page 208: Refrigeration and Air Conditioning

208

Measure

• Airflow Q (m3/s) at Fan Coil Units (FCU) or Air Handling Units (AHU): anemometer

• Air density ρ (kg/m3)

• Dry bulb and wet bulb temperature: psychrometer

• Enthalpy (kCal/kg) of inlet air (hin) and outlet air (Hout): psychrometric charts

Calculate TR ( )3024

h h ρ Q TR outin −××

=

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Assessment of Air Conditioning

Page 209: Refrigeration and Air Conditioning

209

Indicative TR load profile

• Small office cabins: 0.1 TR/m2

• Medium size office (10 – 30 people occupancy) with central A/C: 0.06 TR/m2

• Large multistoried office complexes with central A/C: 0.04 TR/m2

Assessment of Air Conditioning

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Page 210: Refrigeration and Air Conditioning

210

• Accuracy of measurements

• Inlet/outlet temp of chilled and condenser water

• Flow of chilled and condenser water

• Integrated Part Load Value (IPLV)

• kW/TR for 100% load but most equipment operate between 50-75% of full load

• IPLV calculates kW/TR with partial loads

• Four points in cycle: 100%, 75%, 50%, 25%

Considerations for Assessment

Assessment of Refrigeration and ACAssessment of Refrigeration and AC

Page 211: Refrigeration and Air Conditioning

211

Introduction

Reference Handbooks/Standards

Type of refrigeration

Applied Psychrometric

Heat Load Calculation

Air Duct Design

Pressurization System

Chilled/Condenser Water Piping Design

Compressors

Condensers & Evaporators

Expansion Devices

Cooling Tower

Assessment of Refrigeration and AC

Energy Efficiency Opportunities

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Page 212: Refrigeration and Air Conditioning

212

1. Optimize process heat exchange

2. Maintain heat exchanger surfaces

3. Multi-staging systems

4. Matching capacity to system load

5. Capacity control of compressors

6. Multi-level refrigeration for plant needs

7. Chilled water storage

8. System design features

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Page 213: Refrigeration and Air Conditioning

213

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

High compressor safety margins: energy loss

1. Proper sizing heat transfer areas of heat exchangers and evaporators

•Heat transfer coefficient on refrigerant side: 1400 – 2800 Watt/m2K

•Heat transfer area refrigerant side: >0.5 m2/TR

2. Optimum driving force (difference Te and Tc): 1oC raise in Te = 3% power savings

1. Optimize Process Heat Exchange

Page 214: Refrigeration and Air Conditioning

214

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Evaporator Temperature (0C)

Refrigeration Capacity*(tons)

Specific Power Consumption (kW/TR)

Increase kW/TR (%)

5.0 67.58 0.81 -

0.0 56.07 0.94 16.0

-5.0 45.98 1.08 33.0

-10.0 37.20 1.25 54.0

-20.0 23.12 1.67 106.0

(National Productivity Council)Condenser temperature 40◦C

1. Optimize Process Heat Exchange

Condensing Temperature (0C)

Refrigeration Capacity (tons)

Specific Power Consumption (kW /TR)

Increase kW/TR (%)

26.7 31.5 1.17 -

35.0 21.4 1.27 8.5

40.0 20.0 1.41 20.5

*Reciprocating compressor using R-22 refrigerant. Evaporator temperature.-10◦ C

Page 215: Refrigeration and Air Conditioning

215

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

3. Selection of condensers

• Options: • Air cooled condensers

• Air-cooled with water spray condensers

• Shell & tube condensers with water-cooling

• Water-cooled shell & tube condenser• Lower discharge pressure

• Higher TR

• Lower power consumption

1. Optimize Process Heat Exchange

Page 216: Refrigeration and Air Conditioning

216

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

• Poor maintenance = increased power consumption

• Maintain condensers and evaporators• Separation of lubricating oil and refrigerant

• Timely defrosting of coils

• Increased velocity of secondary coolant

• Maintain cooling towers• 0.55◦C reduction in returning water from cooling

tower = 3.0 % reduced power

2. Maintain Heat Exchanger Surfaces

Page 217: Refrigeration and Air Conditioning

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Effect of poor maintenance on compressor power consumption

2. Maintain Heat Exchanger Surfaces

(National Productivity Council)

Condition Te (0C)

Tc (0C)

Refrigeration Capacity* (TR)

Specific Power

Consumption (kW/TR)

Increase kW/TR

(%)

Normal 7.2 40.5 17.0 0.69 -

Dirty condenser 7.2 46.1 15.6 0.84 20.4

Dirty evaporator 1.7 40.5 13.8 0.82 18.3

Dirty condenser and evaporator

1.7 46.1 12.7 0.96 38.7

Page 218: Refrigeration and Air Conditioning

218

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

• Suited for

• Low temp applications with high compression

• Wide temperature range

• Two types for all compressor types

• Compound

• Cascade

3. Multi-Staging Systems

Page 219: Refrigeration and Air Conditioning

219

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

a. Compound

• Two low compression ratios = 1 high

• First stage compressor meets cooling load

• Second stage compressor meets load evaporator and flash gas

• Single refrigerant

b. Cascade

• Preferred for -46 oC to -101oC

• Two systems with different refrigerants

3. Multi-Stage Systems

Page 220: Refrigeration and Air Conditioning

220

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

• Most applications have varying loads

• Consequence of part-load operation • COP increases

• but lower efficiency

• Match refrigeration capacity to load requires knowledge of• Compressor performance

• Variations in ambient conditions

• Cooling load

4. Matching Capacity to Load System

Page 221: Refrigeration and Air Conditioning

221

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

5. Capacity Control of Compressors

• Cylinder unloading, vanes, valves• Reciprocating compressors: step-by-step

through cylinder unloading:

• Centrifugal compressors: continuous modulation through vane control

• Screw compressors: sliding valves

• Speed control• Reciprocating compressors: ensure

lubrication system is not affected

• Centrifugal compressors: >50% of capacity

Page 222: Refrigeration and Air Conditioning

222

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

5. Capacity Control of Compressors

• Temperature monitoring• Reciprocating compressors: return water (if

varying loads), water leaving chiller (constant loads)

• Centrifugal compressors: outgoing water temperature

• Screw compressors: outgoing water temperature

• Part load applications: screw compressors more efficient

Page 223: Refrigeration and Air Conditioning

223

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Bank of compressors at central plant

• Monitor cooling and chiller load: 1 chiller full load more efficient than 2 chillers at part-load

• Distribution system: individual chillers feed all branch lines; Isolation valves; Valves to isolate sections

• Load individual compressors to full capacity before operating second compressor

• Provide smaller capacity chiller to meet peak demands

6. Multi-Level Refrigeration

Page 224: Refrigeration and Air Conditioning

224

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

Packaged units (instead of central plant)

• Diverse applications with wide temp range and long distance

• Benefits: economical, flexible and reliable

• Disadvantage: central plants use less power

Flow control

• Reduced flow

• Operation at normal flow with shut-off periods

6. Multi-Level Refrigeration

Page 225: Refrigeration and Air Conditioning

225

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

• Chilled water storage facility with insulation

• Suited only if temp variations are acceptable

• Economical because• Chillers operate during low peak demand

hours: reduced peak demand charges

• Chillers operate at nighttime: reduced tariffs and improved COP

7. Chilled Water Storage

Page 226: Refrigeration and Air Conditioning

226

Energy Efficiency OpportunitiesEnergy Efficiency Opportunities

• FRP impellers, film fills, PVC drift eliminators

• Softened water for condensers

• Economic insulation thickness

• Roof coatings and false ceilings

• Energy efficient heat recovery devices

• Variable air volume systems

• Sun film application for heat reflection

• Optimizing lighting loads

8. System Design Features

Page 227: Refrigeration and Air Conditioning

227

Training Session on Energy Training Session on Energy EquipmentEquipment

Refrigeration & Air Refrigeration & Air Conditioning SystemsConditioning Systems

THANK YOUTHANK YOU

FOR YOUR ATTENTIONFOR YOUR ATTENTION