CHAPTER 5 Energy Efficient HVAC Design

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Energy Efficient HVAC

Design _Guidelines _Proposed

Mandatory Clause Technical Guidelines Benefits

CHAPTER

5 Energy Efficient HVAC Design

5.1 Guideline

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5.2 Mandatory clause

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5.3 Technical notes

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5.3.1 Guidelines on optimization of cooling load estimation

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Table 5.3.1: Inside design conditions for air-conditioned spaces in the Bangalore city

S. No. Category Inside design conditions

(I) Restaurants DB 23 to 26 C

RH 55 to 60%

(ii) Office buildings DB 23 to 26 C

RH 55 to 60%

(iii) Radio and television studios DB 23 to 26 C

RH 45 to 55%

(iv) Departmental stores DB 23 to 26 C

RH 50 to 60%

(v) Hotel guest rooms DB 23 to 26 C

RH 50 to 60%

(vi) Classroom DB 23 to 26 C

RH 50 to 60%

(vii) Auditoriums DB 23 to 26 C

RH 50 to 60%

(viii) Recovery rooms DB 24 to 26 C

RH 45 to 55 %

(ix) Patient rooms DB 24 to 26 C

RH 45 to 55 %

(x) Operation theatres DB 17 to 27 C

RH 45 to 55 %

(xi) Museums and libraries DB 20 to 22 C

RH 40 to 55 %

(xii) Telephone terminal rooms DB 22 to 26 C

RH 40 to 50 %

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Table 5.3.2: Recommended outdoor design conditions for the Bangalore city for cooling load estimation

Cooling DB/MCWB Cooling WB/MCDB 0.4 % 1.0 % 2.0 % 0.4 % 1.0 % 2.0 % DB MCW B DB MCWB DB MCWB WB MCDB WB MCDB WB MCDB 34.7 19.6 34 19.6 33.1 19.2 23.5 28.9 22.9 28.2 22.5 27.7 1DB: Dry bulb temperature, MCWB: Mean coincidental wet bulb temperature,

WB: Wet bulb temperature, MCDB: Mean coincidental dry bulb temperature

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Outdoor Air Supply Air Exhaust Air Outside Air Damper Energy recovery wheel

Return Air Air

EA and OA Filters

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Table 5.3.3: Minimum ventilation rates in the breathing zone

(This table is not valid in isolation; it must be used in conjunction with the accompanying notes)

People Outdoor Air Rate RP Area Outdoor Air Rate Ra Notes Occupant Density (see Note 4) Combined Outdoor Air Rate (see Note 5) Occupancy category cfm/person L/s person cfm/ft 2_L/s m2 #/1000 ft 2_or #/100 m2 Cfm/person L/s _person Air Class Office Buildings Office space 5 2.5 0.06 0.3 5 17 8.5 1 Reception areas 5 2.5 0.06 0.3 30 7 3.5 1 Telephone/data entry 5 2.5 0.06 0.3 60 6 3.0 1 Main entry lobbies 5 2.5 0.06 0.3 10 11 5.5 1

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5.2.2 Guidelines on AHU specifications to achieve energy efficiency

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Table5.3.4: Values of performance characteristics of two-pole and four-pole energy-efficient induction motors

Rated

output Two-pole motor nominal efficiency Four-pole motor nominal efficiency

(kW) for eff 1 for eff 1

(%) (%) 0.37 70.2 73 0.55 74 78 0.75 77 82.5 1.1 82.8 83.8 1.5 84.1 85 2.2 85.6 86.4 3.7 87.5 88.3 5.5 88.6 89.2 7.5 89.5 90.1 9.3 90 90.5 11 90.5 91 15 91.3 91.8 18.5 91.8 92.2 22 92.2 92.6 30 92.9 93.2 37 93.3 93.6 45 93.7 93.9 55 94 94.2 75 94.6 94.7 90 95 95

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Rated

output Two-pole motor nominal efficiency Four-pole motor nominal efficiency

(kW) for eff 1 for eff 1

(%) (%)

125 95.3 95.5

132 95.3 95.5

160 95.5 95.8

5.2.3 Guidelines for energy-efficient chillers

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S. No. Equipment class Minimum COP Minimum

IPLV Test standard 1 Unitary air cooled air conditioner 19 and <40 kW ( 5.4

and <11 tons )

3.08 ARI 210/240

2 Unitary air cooled air conditioner 40 to <70 kW ( 11 to 3.08 ARI 340/360

3 Unitary air cooled air conditioner 70 kW ( 20 tons) 2.93 2.99 ARI 340/360

4 Unitary water cooled air conditioner <19 kW (<5.4 tons) 4.1 ARI 210/240

5 Unitary water cooled air conditioner 19 and <40 kW ( 5.4 and <11 tons )

4.1 ARI 210/240

6 Unitary water cooled air conditioner <40 kW ( 11 tons ) 3.22 3.02 ARI 210/240

S. No. Equipment class Minimum COP Minimum _IPLV Test standard

1 Air cooled chiller <530 kW (<150 tons) 2.9 3.16 ARI 550/590-1998

2 Air cooled chiller 530 kW ( 150 tons) 3.05 3.32 ARI 550/590-1998

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S. No. Equipment class Minimum COP Minimum

IPLV Test standard 4 Centrifugal water cooled chiller 530 and <1050 kW ( _{150 and <300 tons)} 5.8 6.17 ARI 550/590-1998

5 Centrifugal water cooled chiller 1050 kW ( 300 tons) 6.3 6.61 ARI 550/590-1998

6 Reciprocating compressor, water cooled chiller all sizes 4.2 5.05 ARI 550/590-1998

7 Rotary screw and scroll compressor, Water Cooled Chiller <530 kW

4.7 5.49 ARI 550/590-1998

(<150 tons)

8 Rotary screw and scroll compressor, water cooled 5.4 6.17 ARI 550/590-1998

Chiller 530 and <1050 kW

( 150 and <300 tons)

9

Rotary screw and scroll compressor, water cooled chiller 1050 kW 5.75 6.43 ARI 550/590-1998

5.4 Benefits

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• + , ) )! • D o D ;" 6; ) 7 , 5!$ $!$$$023 < o 8 D -E; 9!2 Payback Period 0 50 100 150 200 250 300 1 2 3 4 5 6 7 8 9 10 Years A m ou n t i n la kh ru p ee s