Undertaken by: Anirudh B

11MN01

PG Scholar

ME Energy Engineering

School of Energy PSG College of Technology

Mentored by: Dr.R.Velavan

Associate Professor

School of Energy

PSG College of Technology

Solar driven Absorption Chiller (SAC) - Phase Change

Material (PCM) Integrated Technology (SAPIT) for

cooling telecommunication shelters in India

Project Phase – I

Review -II

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

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

Literature survey for review II

Model of a telecommunication shelter

Interior of the cabinet

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

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)

Cooling load calculations for telecom shelter

Solar heat gain:

𝑄𝑠 = 𝑈𝐴 𝑇𝑠𝑜𝑙−𝑎𝑖𝑟 − 𝑇𝑖

Where, U - overall heat transfer coefficient of wall and roof, 𝑊/𝑚2𝐾

A -wall and roof area in 𝑚2

𝑇𝑖- Indoor air temperature, 𝐶𝑜

Shelter material: interior and exterior surfaces made of galvanized steel separated by polyurethane foam

Heat transfer coefficient for galvanized steel, hgs=25 𝑊/𝑚2𝐾

Heat transfer coefficient for polyurethane foam, hi=0.0972 𝑊/𝑚2𝐾

Overall heat transfer coefficient is calculated to be, U=0.09645 𝑊/𝑚2𝐾

Sol-air temperature: 𝑇𝑠𝑜𝑙−𝑎𝑖𝑟 = 𝑇𝑜 +𝛼𝐸𝑡

ℎ𝑜−

𝜀∆𝑅

ℎ𝑜

𝑇𝑜- outside air temperature, degC 𝛼

ℎ𝑜= 0.026 for light coloured surfaces

𝜀∆𝑅 = 0K for vertical surfaces and 4K for horizontal surfaces

Courtesy: ASHRAE Fundamentals 2005

Cooling load calculations for telecom shelter

Month Dry bulb temp

deg C

Average daily solar

irradiation , 𝑾/𝒎𝟐𝑲

Sol-air temp,

deg C

Solar heat gain,

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

Equipment heat gain in the telecom shelter:

S.No Unit name Number of

units

Heat load, W

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

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.

Due to economic constraints, the cooling load for the telecom shelter

is scaled down to 500W.

Type of

Cooling

load

Actual

coolin

g

load,

W

Signific

ance of

cooling

load

Actual

cooling

load ,

W

Scaled

down

cooling

load, W

Actual

TR

require

d

Actual

TR

require

d with

PCM

Scaled

down

TR

require

d

Scaled

down

TR

require

d with

PCM

Equipme

nt heat

gain

4310 To be

include

d

4310

500 1.22 TR 2.5TR 0.15TR 0.5TR

Solar

heat gain

14 Negligib

le

- - - - - -

Theoretical model of SAC Thermal energy required by the absorption chiller,

𝑄𝑐ℎ =𝑄𝑐

𝐶𝑂𝑃𝑐ℎ

Where, 𝐶𝑂𝑃𝑐ℎ 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,

𝐶𝑂𝑃𝑐ℎ = 𝑎𝑓𝑐ℎ4 + 𝑏𝑓𝑐ℎ

3 + 𝑐𝑓𝑐ℎ2 + 𝑑𝑓𝑐ℎ + 𝑒

Where, 𝑓𝑐ℎis the ratio of the cooling load and the chiller nominal

capacity and given by

𝑓𝑐ℎ =𝑄𝑐

𝐶𝐻𝑐𝑎𝑝

Energy balance applied at the chiller can be given by,

𝑄𝑐ℎ = 𝑚 𝑐ℎ𝐶𝑐ℎ(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)

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)