4th International Conference on “Advances in Energy Research’’
Department of Energy Science and Engineering
Indian Institute of Technology Bombay
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 & Environment
Malaviya National Institute of Technology Jaipur
• Indian has five distinct climatic zones
with wide variance
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)
• 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)
Water cooled chiller
29.4 C at 100%
23.9 C at 75%
18.3 C at 50%
18.3 C at 25%
30 C at 100%
26 C at 75%
22 C at 50%
18 C at 25%
Air cooled chiller
35 C at 100%
27 C at 75%
19 C at 50%
13 C at 25%
35 C at 100%
30 C at 75%
25 C at 50%
20 C at 25%
Introduction …….. Contd.
• Oriental countries; China, Japan, Malaysia etc have their
own standards based on their climatic conditions.
• Chiller standards for Indian climatic conditions……… An
Objectives of the study
To check the suitability of prevailing rating condition (AHRI)
for HVAC equipments with respect to Indian climatic
Identification of a representative city(s) through statistical
analysis of weather data for different climatic zones.
Weather data analysis of
prominent cities : All climatic
ISHARE weather data
considered in analysis.
Identification of Representative
cities for each climatic zone.
- Through statistical analysis
- Criteria as per GOI classification
- Metro/larger city considered.
Methods … Weather analysis
Zones; Warm & humid
and composite covers more
number of large cities
cities identified for such
Hot & Dry
Warm & Humid
variance observed in
weather profiles within the
zones and in cities within
the same zone.
Analysis : Summary of weather condition in representative
Composite New Delhi
Hot & Dry
X: 30% HRA
Y : 20% HRA
Analysis : Pattern of weather profile of representative
Mumbai Kolkata Chennai Avg of all cities of zone
Avg of all cities of zone
Analysis: Temperature frequency distribution
Post identification detailed analysis of weather data of all
− Temperature frequency distribution of DBT and WBT
for complete year.
− Percentage coverage of total hours in a year at
different temperature condition (DBT/WBT)
Analysis: Temperature frequency distribution of
WBT of representative cities
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
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
There is need to revise the prevailing rating condition according
the Indian climatic condition
the study for unitary air condition system/other
Revision of the part load coefficients
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