1. 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

2. 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)

3. 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:
O
29.4 C at 100%
O
23.9 C at 75%
O
18.3 C at 50%
O
18.3 C at 25%
Condenser EWT:
O
30 C at 100%
O
26 C at 75%
O
22 C at 50%
O
18 C at 25%
Air cooled chiller
Condenser EAT:
O
35 C at 100%
O
27 C at 75%
O
19 C at 50%
O
13 C at 25%
Condenser EAT:
O
35 C at 100%
O
30 C at 75%
O
25 C at 50%
O
20 C at 25%
3

4. Introduction …….. Contd.
• Oriental countries; China, Japan, Malaysia etc have their
own standards based on their climatic conditions.
• Chiller standards for Indian climatic conditions……… An
emergent need.
4

5. 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.
5

6. 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.
6

7. Methods … Weather analysis
 Wide
Zones; Warm & humid
and composite covers more
number of large cities
-Additional representative
cities identified for such
zones
Hot & Dry
Composite
Warm & Humid
50
40
Max
30
DBT C
variance observed in
weather profiles within the
zones and in cities within
the same zone.
20
Min
10
0
Jan
Feb
Mar
Apr May
Jun
Jul
Aug
Sep
Oct
Nov Dec
Months
7

8. Analysis : Summary of weather condition in representative
cities
Type of
city
Annual
Max temp
(OC) DBT
Annual
Min temp
(OC) DBT
Annual
Mean temp
(OC) DBT
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
Climatic
zone
Warm
& Humid
City name
X: 30% HRA
Y : 20% HRA
8

9. Analysis : Pattern of weather profile of representative
cities
in zone
50
Mumbai Kolkata Chennai Avg of all cities of zone
DBT C
40
30
Warm &
humid
20
10
50
New Delhi
 Hyderabad
Dec
Oct
Sep
Nov
Months
Aug
Jul
Jun
May
Apr
Mar
Feb
Jan
0
 Avg of all cities of zone
40
Composite
20
10
Months
Dec
Nov
Oct
Sep
Aug
Jul
Jun
May
Apr
Mar
Feb
0
Jan
DBT C
30
9

10. 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)
10

11. Analysis: Temperature frequency distribution of DBT
of representative cities
City
Coverage
33
34
84.36 88.77
DBT (OC)
35
36
37
91.99 93.97 95.58
38
96.87
39
40
97.79 98.52
New Delhi
% hours
32
80.4
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
11

12. Analysis: Temperature frequency distribution of
WBT of representative cities
WBT (OC)
City
Coverage
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
12

13. 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.
13

14. 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
14

15. Future work
 Extending
the study for unitary air condition system/other
HVAC equipments
 Revision of the part load coefficients
15

16. Reference
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