The document discusses: 1) Literature review on passive cooling systems using phase change materials for telecom shelters. 2) Meteorological data collection for Peelamedu region showing average monthly dry bulb temperatures. 3) Calculations of cooling load for a telecom shelter accounting for solar heat gain and equipment heat gain. 4) A theoretical model of a solar absorption chiller integrated with phase change material for providing cooling to the telecom shelter.

1. Project Phase – I
Review -II
Solar driven Absorption Chiller (SAC) - Phase Change
Material (PCM) Integrated Technology (SAPIT) for
cooling telecommunication shelters in India
Undertaken by: Anirudh B Mentored by: Dr.R.Velavan
11MN01 Associate Professor
School of Energy
PG Scholar PSG College of Technology
ME Energy Engineering
School of Energy
PSG College of Technology

2. Literature survey for review II
An experimental investigation on passive cooling system
comprising phase change material and two-phase closed
thermosyphon for telecom shelters in tropical and desert regions
A.Shanmuga Sundaram , R.V.Seeniraj , R.Velraj
Energy and Buildings (2010)
The authors have developed a passive cooling system employing PCM
and TPCT for an alternative to conventional cooling systems to provide
thermal management of telecommunication equipment's in telecom
shelters
Thermodynamic and economic performance of the LiBr–H2O
single stage absorption water chiller
Tomasz M.Mroz
Applied Thermal Engineering (2006)
The authors have developed and installed a single stage LiBr-H2O
absorption chiller in a municipal CHP plant to study the energy
efficiency and economic analysis of the system

3. Literature survey for review II
Energy and economic analysis of an integrated solar absorption
cooling and heating system in different building types and
climates
Tiago Mateus , Armando C. Oliveira
Applied Energy, (2009)
The authors have modeled and simulated an integrated solar absorption
cooling and heating system in buildings of three different regions using
TRNSYS and evaluated the total energy cost and CO2 emissions reduction
Exergy calculation of lithium bromide–water solution and its
application in the exergetic evaluation of absorption refrigeration
systems LiBr-H2O
Reynaldo Palacios-Bereche, R. Gonzales, S. A. Nebra
International Journal of Energy Research(2010)
The authors have calculated the physical and chemical exergies of the system
by evaluating the irreversibilities and extending it to determine the exergetic
efficiency of the system, thereby providing this as a reference to calculate
for other complex systems

4. Model of a telecommunication shelter

5. Interior of the cabinet

6. Meteorological data collection (DBT deg C)for peelamedu region
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1970 25.329 25.79 27.5 28.296 27.417 26.01 25.18 25.207 25.732 25.646 25.432 24.363
1971 25.27 25.748 26.923 28.239 27.199 25.099 24.702 25.128 25.603 25.513 24.93 24.07
1972 23.995 25.547 26.851 28.695 26.85 26.745 25.175 25.968 26.431 26.035 25.654 25.486
1973 25.505 26.404 28.005 29.356 28.66 26.488 25.884 24.899 26.001 25.901 25.287 24.851
1974 24.817 25.692 27.714 28.842 27.454 26.665 25.358 24.99 25.673 25.782 25.801 25.107
1975 24.765 26.714 27.921 28.922 27.375 25.265 25.342 25.228 25.281 25.291 25.331 24.446
1976 24.144 25.028 27.552 27.711 28.264 26.767 25.457 25.386 26.162 26.342 25.672 25.306
1977 25.141 26.367 27.675 28.737 27.074 26.275 25.107 26.134 25.961 25.952 25.598 24.859
1978 25.113 25.864 27.582 28.767 26.811 25.228 24.444 25.029 25.893 26.184 25.918 25.203
1979 26.097 26.772 28.015 28.867 27.827 26.093 24.525 25.532 25.56 25.963 25.197 25.746
1980 25.012 26.367 27.639 28.194 28.005 24.921 24.401 25.117 26.256 25.957 26.169 25.825
1981 25.634 26.503 27.662 28.512 27.807 25.246 24.92 24.94 25.343 25.936 25.337 25.009
1982 25.181 26.521 27.871 29.312 27.849 26.505 25.801 26.062 26.566 26.922 26.616 25.245
1983 25.503 27.483 28.619 29.696 29.329 27.66 26.295 25.965 25.752 26.526 26.023 25.542
1984 25.724 26.008 26.98 27.996 28.987 25.8 25.375 25.697 26.124 25.892 26.212 25.308
1985 25.991 26.926 28.435 29.195 28.356 25.679 25.668 25.75 26.473 26.168 25.792 25.753
1986 25.533 26.248 28.096 29.54 28.712 26.505 26.353 25.472 26.217 26.788 26.054 26.128

7. Meteorological data collection (DBT deg C)for peelamedu region
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1987 25.85 26.079 27.784 29.379 28.801 26.729 27.076 26.147 27.431 26.962 26.694 26.007
1988 25.672 27.502 28.565 28.383 28.578 27.087 25.9 25.923 26.001 26.831 26.077 25.25
1989 25.364 25.71 27.258 28.807 28.254 26.145 25.667 25.883 25.807 26.407 26.244 25.486
1990 25.144 26.735 28.087 29.395 27.792 26.701 25.593 25.672 26.408 26.398 26.094 25.486
1991 25.997 26.71 28.295 28.906 29.13 26.296 25.613 25.379 26.738 25.989 25.862 25.081
1992 24.501 26.399 27.452 28.976 27.981 26.623 25.47 25.697 26.089 26.024 26.01 24.748
1993 24.696 25.831 27.752 28.893 28.39 26.856 25.442 26.112 26.264 25.995 25.912 25.107
1994 25.482 26.538 27.876 28.183 28.321 26.457 25.357 26.055 26.611 26.169 25.951 25.018
1995 25.662 27.092 27.698 28.735 27.518 27.316 25.971 26.143 26.444 26.732 26.72 25.198
1996 25.918 26.527 28.105 28.51 28.991 26.718 25.976 25.848 26.001 26.234 26.538 24.755
1997 25.718 26.599 27.82 27.915 28.317 27.635 26.119 26.126 26.559 26.705 26.732 26.41
1998 26.48 27.596 28.911 29.62 28.583 27.453 25.939 26.335 26.077 26.26 26.408 25.604
1999 25.613 26.409 28.442 28.374 26.614 26.182 25.619 26.126 26.884 26.301 26.289 25.478
2000 26.178 26.879 27.88 28.582 28.094 26.004 25.892 25.562 26.384 26.288 26.563 25.317
2001 26.218 27.578 28.41 28.541 28.001 26.442 25.901 25.686 26.604 26.285 26.447 25.521
2002 26.214 26.173 28.171 28.899 28.104 26.828 26.382 26.152 27.238 26.701 26.274 25.891
Courtesy: Indian Meteorological department (www.indiawaterportal.org)

8. Cooling load calculations for telecom shelter
Solar heat gain:
𝑄 𝑠 = 𝑈𝐴 𝑇 𝑠𝑜𝑙−𝑎𝑖𝑟 − 𝑇𝑖
Where, U - overall heat transfer coefficient of wall and roof, 𝑊/𝑚2 𝐾
A -wall and roof area in 𝑚2
𝑇𝑖 - Indoor air temperature, 𝑜 𝐶
Shelter material: interior and exterior surfaces made of galvanized steel
separated by polyurethane foam
Heat transfer coefficient for galvanized steel, hgs=25 𝑊/𝑚2 𝐾
Heat transfer coefficient for polyurethane foam, hi=0.0972 𝑊/𝑚2 𝐾
Overall heat transfer coefficient is calculated to be, U=0.09645 𝑊/𝑚2 𝐾
𝛼𝐸 𝑡 𝜀∆𝑅
Sol-air temperature: 𝑇 𝑠𝑜𝑙−𝑎𝑖𝑟 = 𝑇 𝑜 + −
ℎ𝑜 ℎ𝑜
𝑇 𝑜 - outside air temperature, degC
𝛼
= 0.026 for light coloured surfaces
ℎ𝑜
𝜀∆𝑅 = 0K for vertical surfaces and 4K for horizontal surfaces
Courtesy: ASHRAE Fundamentals 2005

9. Cooling load calculations for telecom shelter
Month Dry bulb temp Average daily solar Sol-air temp, Solar heat gain,
deg C irradiation , 𝑾/𝒎 𝟐 𝑲 deg C W
Jan 25.62 632.8 42.07 9.88
Feb 26.62 728.9 45.58 11.90
Mar
27.99 811.3 49.08 13.93
Apr 28.80 758.9 48.53 13.62
May 28.28 730.2 47.26 12.88
Jun 26.51 605.3 42.25 9.98
Jul 25.77 561.6 40.37 8.89
Aug 25.81 579.1 40.87 9.18
Sep 26.35 624.1 42.58 10.17
Oct 26.36 555.4 40.80 9.14
Nov 26.21 526.7 39.91 8.63
Dec 25.44 556.7 39.91 8.63
Courtesy: NASA Surface meteorology and solar energy

10. Equipment heat gain in the telecom shelter:
S.No Unit name Number of Heat load, W
units
1 Power cabinet :electronics 1 450
2 2G cabinet 1:electronics 1 1050
3 2G cabinet 2:electronics 1 1050
4 2G cabinet 3:electronics 1 1050
5 Nokia Node B - RRU 1 1 150
6 Nokia Node B - BBU 1 100
7 Nokia Node B - RRU 2 1 150
8 Nokia Node B - ALM 1 50
9 Nokia Node B - RRU 3 1 150
10 2G,3G,power Cabinet door fans (150CFM) 20 100
11 Rectifier fans (48CFM) 8 10
Total heat load 4310
Courtesy: Bharathikrishanan Muralidharan, “Energy based Design optimization of
Telecommunication cabinets”, MS thesis, University of Texas, 2010

11. Tonnage of refrigeration required
Actual cooling load required for telecom shelter:
Solar heat gain + Equipment heat gain
But the solar heat gain is negligible compared to the equipment heat
gain therefore it is neglected.
Type of Actual Signific Actual Scaled Actual Actual Scaled Scaled
Cooling coolin ance of cooling down TR TR down down
load g cooling load , cooling require require TR TR
load, load W load, W d d with require require
W PCM d d with
PCM
Equipme 4310 To be 4310 500 1.22 TR 2.5TR 0.15TR 0.5TR
nt heat include
gain d
Solar 14 Negligib - - - - - -
heat gain le
Due to economic constraints, the cooling load for the telecom shelter
is scaled down to 500W.

12. Theoretical model of SAC
Thermal energy required by the absorption chiller,
𝑄𝑐
𝑄 𝑐ℎ =
𝐶𝑂𝑃 𝑐ℎ
Where, 𝐶𝑂𝑃 𝑐ℎ is the coefficient of performance of the absorption
chiller which varies with demand is given in a fourth order polynomial
for partial load efficiency of absorption chiller,
4 3 2
𝐶𝑂𝑃 𝑐ℎ = 𝑎𝑓𝑐ℎ + 𝑏𝑓𝑐ℎ + 𝑐𝑓𝑐ℎ + 𝑑𝑓𝑐ℎ + 𝑒
Where, 𝑓𝑐ℎ is the ratio of the cooling load and the chiller nominal
capacity and given by
𝑄𝑐
𝑓𝑐ℎ =
𝐶𝐻 𝑐𝑎𝑝
Energy balance applied at the chiller can be given by,
𝑄 𝑐ℎ = 𝑚 𝑐ℎ 𝐶 𝑐ℎ (𝑇ℎ1 − 𝑇ℎ2 )
Courtesy: N. Fumo, V. Bortone, J. C. Zambrano, “Solar Thermal Driven Cooling System for a Data
Center in Albuquerque New Mexico”, Journal of Solar Energy Engineering, ASME(2011)

13. Future work in phase I
Daily cooling load profile of a telecom shelter in Coimbatore region
Determination of theoretical COP for part load efficiency of
absorption chiller (by polynomial curve fitting)
Determination of thermal energy required by the absorption chiller
Determination of cooling load of telecom shelter under transient
condition using TRNSYS software
Determination of the required area of the solar thermal collectors
Determination of capacity of the other heat transfer elements in
the chiller( like cooling tower, evaporator, condenser)