Analysis of weather conditions of Indian cities with respect to rating conditions for HVAC equipments

Pramod Kumar, Manoj Singh, Anant Joshi, Jyotirmay Mathur

Center for Energy & EnvironmentMalaviya National Institute of Technology Jaipur

4th International Conference on “Advances in Energy Research’’Department of Energy Science and Engineering

Indian Institute of Technology Bombay

Introduction

• Indian has five distinct climatic zones with wide variance

• HVAC ratings have direct dependence on weather conditions. • Presently HVAC systems in India are rated as per AHRI standards.

•Outdoor Rating conditions based on DBT (air cooled) & WBT(water cooled)

Introduction……..Contd.

• Rating condition should be country specific – recommendations by ISO 19289 for rating of HVAC equipments • European countries have separate standard (Eurovent 14511) even with marginal difference with AHRI standards (550/590)

Chiller type AHRI Eurovent

Water cooled chiller

Condenser EWT: 29.4 OC at 100% 23.9 OC at 75%18.3 OC at 50%18.3 OC at 25%

Condenser EWT: 30 OC at 100% 26 OC at 75%22 OC at 50%18 OC at 25%

Air cooled chiller

Condenser EAT: 35 OC at 100% 27OC at 75%19 OC at 50%13 OC at 25%

Condenser EAT: 35 OC at 100% 30 OC at 75%25 OC at 50%20 OC at 25%

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• Oriental countries; China, Japan, Malaysia etc have their own standards based on their climatic conditions.

• Chiller standards for Indian climatic conditions……… An emergent need.

Introduction …….. Contd.

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Objectives of the study

To check the suitability of prevailing rating condition (AHRI) for HVAC equipments with respect to Indian climatic conditions.

Identification of a representative city(s) through statistical analysis of weather data for different climatic zones.

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Methodology

Weather data analysis of prominent cities : All climatic zones.

ISHARE weather data considered in analysis.

Identification of Representative cities for each climatic zone.- Through statistical analysis- Criteria as per GOI classification for cities.- Metro/larger city considered.

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Methods … Weather analysis

Wide variance observed in weather profiles within the zones and in cities within the same zone.

Zones; Warm & humid and composite covers more number of large cities -Additional representative cities identified for such zones

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50

Hot & Dry Composite

Warm & Humid

Min

Max

DB

T°C

Months

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Climatic zone City name Type of

cityAnnual

Max temp(OC) DBT

AnnualMin temp(OC) DBT

AnnualMean temp

(OC) DBT

Warm & Humid

Mumbai X 37.6 13.0 25.3

Chennai X 43.4 18.6 31.0

Kolkata X 39.8 9.4 24.6

Composite New Delhi X 44.0 5.0 24.5

Hyderabad X 41.7 11.6 26.6

Hot & Dry Ahmedabad Y 43.2 9.6 26.4

Moderate Bangalore X 37.1 13.4 25.2

Analysis : Summary of weather condition in representative cities

X: 30% HRAY : 20% HRA

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Jan

Feb

Mar

Apr

May Jun

Jul

Aug Sep Oct

Nov

Dec

0

10

20

30

40

50Mumbai Kolkata Chennai Avg of all cities of zone

DB

T°C

Months

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

10

20

30

40

50 New Delhi Hyderabad Avg of all cities of zone

DB

T °

C

Months

Warm & humid

Composite

Analysis : Pattern of weather profile of representative cities in zone

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Analysis: Temperature frequency distribution

Post identification detailed analysis of weather data of all representative cities

− Temperature frequency distribution of DBT and WBT for complete year.

− Percentage coverage of total hours in a year at different temperature condition (DBT/WBT)

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Analysis: Temperature frequency distribution of DBT of representative cities

City CoverageDBT (OC)

32 33 34 35 36 37 38 39 40New Delhi % hours 80.4 84.36 88.77 91.99 93.97 95.58 96.87 97.79 98.52

Mumbai % hours 92.05 96.68 98.82 99.54 99.92 99.99 99.99 99.99 99.99

Chennai % hours 83.95 89.02 93.34 95.98 97.51 98.39 99.05 99.46 99.61

Hyderabad % hours 87.55 90.13 92.23 94.38 96.35 97.69 98.93 99.43 99.78

Kolkata % hours 88.8 92.32 95.13 96.91 98.34 99.33 99.82 99.97 99.99

Ahmedabad % hours 78.37 82.75 86.14 88.77 91.35 93.46 95.19 96.76 97.82

Bangalore % hours 96.59 98.18 99.12 99.76 99.94 99.99 99.99 99.99 99.99

Average % hours 86.82 90.49 93.36 95.33 96.77 97.78 98.55 99.06 99.39

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Analysis: Temperature frequency distribution of WBT of representative cities

City CoverageWBT (OC)

25 26 27 28 29

New Delhi % hours 76.04 84.21 92.99 98.28 99.62

Mumbai % hours 64.35 84.10 96.66 99.65 99.98

Chennai % hours 63.11 81.22 93.72 98.80 99.50

Hyderabad % hours 98.92 99.82 99.93 99.99 99.99

Kolkata % hours 55.39 68.03 82.05 92.44 97.31

Ahmedabad % hours 71.61 85.06 94.38 99.70 99.97

Bangalore % hours 99.92 99.97 99.99 99.99 99.99

Average % hours 71.57 83.74 93.29 98.14 99.28

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Summary: Observations

Coverage of percentage of total hrs/yr at particular temperature condition different for each representative cities.

on an average basis AHRI rating conditions for air cooled chiller covers only 95.33% of total hrs in a year.

With urban heat island (UHI) consideration of 3OC, the AHRI condition would come to 32OC cover only 86.82% of total hrs in a year.

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Conclusion

Analytical status underline the variance of temperature condition compared to existing rating condition for chillers (Air cooled). WBT rating condition for water cooled chiller is suitable as per Indian climatic conditions.

Any further increment of temperature would increase coverage of hrs.

There is need to revise the prevailing rating condition according the Indian climatic condition

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Future work

Extending the study for unitary air condition system/other HVAC equipments

Revision of the part load coefficients

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Reference

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Thanks

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