THERMODY AMIC, ECO OMIC A ALYSIS THE REQUIREMENTS FOR THE DEGREE OF

THERMODY	AMIC, ECO	OMIC A	ALYSIS  THE REQUIREMENTS FOR THE DEGREE OF
THERMODYAMIC, ECOOMIC AALYSIS
AD DESIGIG OF HEATIG SYSTEM FOR THE
SWIMMIG POOL PRESET AT IT ROURKELA
A THESIS SUBMITTED IN PARTIAL FULFILMENT OF
THE REQUIREMENTS FOR THE DEGREE OF
Bachelor in Technology
In
Chemical Engineering
Under the guidance of
Prof. SK. Agarwal
By
Priyanka Tiwari
107 CH 034
Department of Chemical Engineering
National Institute of Technology, Rourkela
2007-2011
1
National Institute of Technology
Rourkela
CERTIFICATE
This is to certify that the thesis entitled ““Thermodynamic,
Thermodynamic, economic analysis and designing
of heating system for the swimming pool present at NIT Rourkela”” submitted by Priyanka
Tiwari (107CH034) in partial fulfilment for the requirements for the award of Bachelor of
Technology Degree
gree in Chemical Engineering at National Institute of Technology, Rourkela
(Deemed University) is an au
authentic work carried out by her under my supervision and
guidance.
To the best of my knowledge, the matter embodied in the thesis has not been submitted by
any other University/Institute for the award of any Degree or Diploma.
Date:
Professor. S.K Agarwal
Department of Chemical Engineering
National Institute of Technology
Rourkela-769008
Rourkela
2
ACKOWLEDGEMET
I am extremely thankful to Professor S.K. Agarwal for giving me an opportunity to work on
such an interesting live project which gave me an indepth understanding of the way in which
practical work is carried out. I express my sincere gratitude to the suggestions, guidelines and
feedback given by him which helped me in doing the project successfully. I am grateful to
him for his critical analysis of every problem I discussed with him.
I extend my thanks to Professor R.K. Singh and Professor H.M. Jena for providing me with
an opportunity to work on this project.
I am very thankful to Mr. Santosh Naik, swimming trainer, ASF, NIT Rourkela who helped
us in recording the pool temperature and providing us with the details of the pool.
Date:
Priyanka Tiwari
107CH034
3
ABSTRACT
The swimming pool at NIT Rourkela, presently, has no heating system to heat the pool water
during winters. Therefore, it is rendered unused during winters. The focus of this project is on
designing an efficient and economically viable system to heat the swimming pool.
Temperatures of pool water and air above the surface of pool water were recorded for the
month of November (2010). Using this data, losses associated with the pool were calculated
and were found to agree completely with the literature data. Three systems were proposed
based on: heat pumps, natural gas heaters and solar based water heating system. A design has
been proposed for solar based water heating system. Many models of heat pumps were
considered and a detailed cost analysis was made. For natural gas heaters, different models
were considered and cost analysis was carried out. Annual operating cost of heat pumps and
natural gas heaters were compared and natural gas heaters were found to be about 1.8-3 times
costlier than heat pumps. A combination of solar heating and a conventional heater in equal
proportion has been proposed for a perfect heating system. Thermodynamic and economic
analysis and designing of different systems for pool heating has been carried out in this work
4
COTETS
CHAPTER
NO
TOPIC
1
2
2.1
2.2
2.3
3
3.1
3.2
3.3
3.4
3.5
4
4.1
4.2
4.3
4.4
4.5
5
5.1
5.2
5.3
6
6.1
6.2
6.3
6.4
6.5
6.6
Abstract
List of figures
List of tables
Nomenclature
Introduction
Literature review
Heat losses associated with the swimming pool
Methods to heat the swimming pool
Previous work done on swimming pool heating by
researchers
Experimental
Tabulation of temperature during winters
Evaluating losses from swimming pool using the
experimental data
Design parameters for a heating system based on heat
pumps
Design of solar panel for heating system
Design parameters using gas heaters for heating
swimming pool water
Sample calculations
Pool water volume calculation
Calculation for heat requirement by pool for a 10
degree rise in temperature
Sample calculations of heat losses using equations
developed by Brambley
Sample calculation for the operating cost of a heat
pump
Sample calculation for the operating cost of a gas
heater
Designing of heating systems using different sources
Designing of heating systems based on heat pumps
Designing of heating system based on solar energy
Designing of heating system based on gas heaters
Results and discussions
Monthly variation of pool water and ambient air
temperature at different times in a day
Determination of losses from temperature data
Economic analysis of heat pump based water heating
system
Economic analysis of natural gas heater based water
heating system
Cost comparison between heat pumps and natural gas
heaters
Designing of water heating system based on solar
energy
5
PAGE NO
4
7
8
9
10
13
14
18
29
34
35
39
40
41
42
43
44
45
46
49
50
51
52
53
54
55
56
59
63
66
67
69
7
Conclusions
Scope for future work
References
6
71
73
74
LIST OF FIGURES
FIGURE
NO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
FIGURE CAPTION
A view of swimming pool at NIT Rourkela
%of various losses in a pool
Schematic diagram of a gas heater
Schematic diagram of a heat pump
Schematic diagram of a solar water heating system
Schematic diagram of an electric resistance heater
Pool cover
Solar sun ring
Design of the proposed solar panel
Schematic diagram of swimming pool at NIT Rourkela
Flowsheet showing heat pumps as heating medium
Flowsheet of solar panel being used as heating medium
Flowsheet showing natural gas heater being used as heating source
Variation of pool water and air temp with each day of month at
6:00am
Variation of pool water and air temp with each day of month at
7:30am
Variation of pool water and air temp with each day of month at
9:00am
Variation of pool water and air temp with each day of month at
12:00 noon
Variation of pool water and air temp with each day of month at
4:00pm
% contribution of each loss on 8th November
% contribution of each loss on 12th November
% contribution of each loss on 13th November
% contribution of each loss on 14th November
% contribution of each loss on 19th November
Plot of KW rating Vs monthly operating cost
Plot of KW rating Vs no. of units required
KW rating Vs monthly operating costs and no. of units required
Cost comparison between heat pumps and natural gas heaters
Flow sheet showing the connections of the solar panel and its basic
design
7
PAGE
NO
12
17
18
20
24
25
27
28
41
44
52
53
54
56
57
57
58
58
60
61
61
62
62
65
65
67
69
70
LIST OF TABLES:
TABLE NO.
1
2
3
4
5
6
7
8
9
TABLE CAPTION
Pool and air temperature at 6:00am and 6:40am for
November
Pool and air temperature at 7:30am and 9:00am for
November
Pool and air temperature at 12:00 noon and 4:00pm for
November
Specifications of heat pumps used in designing the system
and economic analysis
Specifications of natural gas heaters used in designing and
economic analysis
Losses calculation at 12:00 noon
Cost analysis and no. Of unit required for each model
Monthly operating costs and no. of units required for each
model of gas heater
Cost comparison between heat pumps and natural gas
heaters
8
PAGE NO.
35
36
37
40
42
59
64
66
68
OMECLATURE
A
Area of the swimming pool (m2)
C1
Constant (=8.87*10-5 KW/m2-Pa)
C2
Constant (=7.78*10-5 KW/m3-Pa)
Cp
Specific heat capacity (KJ/Kg degree Celsius)
h
Convective heat transfer coefficient (W/m2 degree Celsius)
hfg
Latent heat of vaporization (KJ/Kg)
m
Mass (Kg)
m*
Evaporation mass flux density from surface of pool (Kg/s-m2)
Pv,s
Partial pressure of water vapour at pool surface (Pa)
Pv,e
Vapour pressure of water far from surface (Pa)
Qcond
Heat loss due to conduction (KW)
Qconv
Heat loss due to convection (KW)
Qeva
Heat loss due to evaporation (KW)
Qrad
Heat loss due to radiation (KW)
Qtotal
Total heat loss (KW)
Ta
Temperature of air far from pool (degree Celsius)
Tg
Temperature of the ground (degree Celsius)
Ts
Temperature of water at the surface of pool (degree Celsius)
U
Average overall conduction heat transfer coefficient (W/m2 degree Celsius)
t
Temperature
GREEK SYMBOLS:
σ
Stefan Boltzman constant (=54.67*10-8 W/m2 K4)
υ
Air velocity (m/s)
∆
Difference
9
10
Introduction:
NIT Rourkela has a great recreation centre in the form of the swimming pool housed in its
campus. Students, faculties and staff enjoy the benefits of swimming pool which not only
provides a great source of fun and enjoyment but also is a great way to remain healthy and fit.
Presently, the swimming season available in the pool is from March to November. The reason
for its unavailability during peak winter months is the absence of a heating system to heat the
pool water. The pool is therefore rendered unused in the winter season.
To extend the benefits of swimming pool throughout the year, a heating system needs to be
installed in the pool which can provide a comfortable swimming temperature during winters.
OBJECTIVE OF THE PROJECT:
•
The aim of this project is to design a heating system for the swimming pool which is
both effective in heating as well as cost effective.
•
Different methods available to heat a swimming pool needs to be thoroughly reviewed
and their advantages and disadvantages studied properly to have a perfect heating
system.
•
Losses associated with the pool needs to be calculated to get a view of % loss
contribution of every loss and take measures accordingly.
•
Cost analysis of different system needs to be done to assess their economic viability
as a heating medium.
•
Designing a system based on renewable energy to minimize the dependence on
conventional heaters.
11
The dimensions of the Institute swimming pool are:
Length: 50metre
Width: 22metre
Depth: 1.8metre (i.e. 6 feet) for the first 25 metres of length which gradually
decreases to 0.9metre (i.e. 3feet) for the next 25 metres of length.
Figure 1: A view of swimming pool at NIT Rourkela.
12
13
2.1 HEAT LOSSES ASSOCIATED WITH THE SWIMMIG POOL:
1. EVAPORATIVE LOSSES: [1],[2]
This is a latent heat loss which accounts for the maximum heat loss from any swimming pool.
This loss occurs when the surface water on pool gets converted to vapour state and gets
carried away by the air. The basic reason for this latent heat loss is the fact that the partial
pressure of ambient air is lower than the saturation vapour pressure at pool temperature. Both
diffusive and conductive mass transfers are the mechanism involved in the vaporisation
process. This loss constitutes about 70% of the total heat losses from the pool, both indoor
and outdoor pool. There are many correlations available in literature to calculate evaporative
losses.
Factors affecting evaporation rate are:
•
Temperature of pool
•
Air temperature
•
Humidity
•
Wind speed at the surface of pool.
Evaporation rate is increased by:
•
High wind speed
•
Low pool water temperature
•
High air temperature
•
Low relative humidity
14
2. CONVECTIVE LOSSES: [1],[2]
This is a sensible heat loss and is closely linked with evaporative losses. This loss is
associated with the temperature difference between pool water and the surrounding air. There
is a dominance of natural convection rather than forced when the water or air velocities are
negligible. Evaporation is an enhancing factor in increasing the natural convection as it is
associated with creating differences in the density of air. There is no sensible heat loss by
convection when the temperature of air and water is equal. There are various correlations
available in the literature to predict the convective heat loss.
The factors affecting the convective heat loss are:
•
Wind speed
•
Air temperature
•
Pool water temperature
Convection losses are enhanced by:
•
High wind speed
•
Low air temperature
•
High pool temperature
3. RADIATION HEAT LOSS: [1],[2]
This loss occurs when the warmer pool radiates heat to cooler sky. By the method of infrared
radiation exchange, heat is transferred from the pool surface to sky. Air is the transparent
medium in this exchange process.
15
Net radiative heat loss from pool surface to air = radiation emitted from pool- (reflected
radiation+infrared radiation emitted by walls that is absorbed by pool).
There are many equations available to determine the radiative heat losses. To use the
formulas, emittance of the water, air and pool surface must be known.
Radiative heat loss consists of about 20-30% of the total heat loss in outdoor pools.
Factors affecting radiation heat loss are:
•
Sky conditions
•
Humidity
•
Pool temperature
Radiative losses are increased by:
•
Clear sky
•
Low relative humidity
•
High pool temperature
4. LOSSES DUE TO CONDUCTION: [1],[2]
These constitute a very small percentage of the total losses associated with the pool.
Conduction losses are through the bottom and sides of the pool. Standard Heat transfer
equation can be used to assess this loss.
This loss is increased by:
•
High wind speed
•
High pool temperature
16
•
Low air temperature
5. LOSSES DUE TO GROUND: [1],[2]
For an in ground pool, these losses are less than 10% of the total heat loss since ground is a
good insulator.
We can see the percentage of all the losses in the following pie chart:
% of total loss
10
evaporative
20
radiative
others
70
Figure 2: %of various losses in a pool.
17
2.2 METHODS TO HEAT THE SWIMMIG POOL:
(A) Use of Active devices:
(1) GAS HEATING
Gas heaters burn propane or natural gas to heat the pool. This is one of the most widely used
methods to heat the pool. Gas heating is very efficient.
Working:[16]
The gas heater consists of a number of finned copper tubes running back and forth above a
burner tray. On the burner tray, gas is ignited to warm the copper tubing and water from the
filtration chamber is passed through. The pool water absorbs heat as it passes through the
heated copper tubing and is then returned to the pool. This is the basic principle of gas
heating. Heat exchanger is the main part of these heaters.
Figure 3: schematic diagram of a gas heater.[17]
18
Advantages of gas heating:
•
Gas heaters are available widely in different sizes and prices.
•
Can heat up the pool water upto any desired temperature in any weather conditions.
•
Least polluting of all the fossil fuels.
•
Provides heating according to need and efficiently.
Disadvantages of gas heating:
•
High operating cost.
•
It uses the fast depleting fossil fuel i.e. natural gas which contributes in the
environmental problems of the world.
(2) HEAT PUMP
It is also a widely used method to heat the swimming pool water. These heat pumps take the
heat out from outside air and divert this heat to the pool. For every unit of electricity
consumed, heat pumps generate three to five units of usable energy.
Working: [18]
The heat pump consists of:
•
Evaporator air coil
•
Heat exchanger
•
Compression and expansion valves
•
Refrigerant (R-22 or R-12)
19
Heat pump fan circulates air through the outer evaporator air coil that acts as a heat collector.
The liquid refrigerant present in the air coil absorbs this heat and gets converted to gaseous
state. This gaseous refrigerant is then pumped by the compressor into the heat exchanger.
This warm gas intensifies the heat and thus the heat is exchanged between the warm
refrigerant gas and the relatively cool pool water. After heat exchange, the refrigerant reverts
back to its liquid state, and is pumped into the expansion valve into the evaporator air coil.
Figure 4: schematic diagram of a heat pump.[18]
Coefficient of performance (COP) of a heat pump determines the efficiency of the heat pump.
Generally it ranges from three to five for the heat pumps.
20
Advantages of a heat pump:
•
Provides heat whenever required and is highly efficient.
•
Is cheaper than a gas heater and an electric resistance heater.
Disadvantages of a heat pump:
•
Uses CFC’s (chloro fluoro carbons), which is a major contributor to the ozone layer
depletion. Therefore it is harmful to the environment.
•
Heats slowly as compared to a gas or an electric resistance heater.
•
High costs involved.
(3) SOLAR WATER HEATING SYSTEMS [19]
Heating of swimming pool by the use of solar energy is one of the most environment friendly
ways for heating. Though solar systems are not very commonly used systems to heat the
pool, but once installed properly they can be very economical and efficient.
Solar Water Heating Systems
Active: one which requires electric power for its operation.
Passive: relies on natural forces to operate.
Direct: heats the water directly in the collector.
Indirect: heats another fluid and transfers this heat to water.
21
Working:
Sun heats up the absorber surface present inside a solar collector. A heat transfer fluid or
water to be heated itself flows through tubes attached to the absorber and gets heated up. This
heated water is stored in a separate water heater tank, so that the heated water can be used
when required.
There are various systems designed based on usage:
Low Temperature systems: operates at about 10 degree Celsius above the
ambient temperature. Used for heating swimming
pools.
Mid Temperature systems: operates at 10-50 degree Celsius above the outside
temperature. Used for domestic water heating.
High Temperature systems: these are mostly used for absorption cooling or
electricity generation.
The various components of solar water heating systems are:
Solar Collectors: these are the main components of a solar water
heating (SWH) system. They collect and concentrate the
solar energy and transfer this heat to fluids. Unglazed
collectors generate small temperature rise and are fit for
22
low temperature applications. For higher temperatures,
glazed collectors are required.
Thermal Storage: tanks are used as storage devices to store heated water.
Controller system: controllers are used to read the temperatures and give
instructions accordingly to other devices to start or stop
functioning.
In the case of SWH systems, a backup heater(based on gas or electricity as source) can be
used so that hot water is supplied even in absence of sunny days.
Advantages of SWH systems
•
Renewable source of energy.
•
Non polluting energy source.
•
Low operating cost.
•
Best source for heating swimming pool without wasting gas or electricity.
Disadvantages of SWH systems
•
Lot of space required for solar panel installation.
•
In the absence of sun, no heating, therefore the need of fossil fuel heater arises.
•
SWH systems don’t provide heat on demand.
23
Figure 5: schematic diagram of a solar water heating system. [20]
(4) ELECTRIC RESISTANCE HEATERS
These are the typical heaters which use electricity as input to heat the pool water. These are
the direct type pool heating device and have a heater inside them which heats up the pool
water.
Advantages:
•
Electricity is available throughout the year, everywhere.
•
These heaters are flameless and provide heat on demand.
24
Disadvantages:
Electricity is very costly. These heaters consume a lot of electricity.
Figure 6: schematic diagram of an electric resistance heater. [21]
(B) Use of Passive Devices:
1 USE OF SWIMMING POOL COVERS:
Pool covers essentially are large sheets that cover the surface of pool. The maximum heat loss
occurs from the surface of pool in the form of evaporative heat loss. If this heat loss can be
restricted, a lot of energy can be saved to heat the pool. Pool covers serve this purpose of
25
reducing the evaporative heat loss. Savings of about 50-70% on heating the pool can be
obtained by using a pool cover.
Advantages of a pool cover:
•
It reduces the evaporative heat loss effectively.
•
Reduces heating costs upto 50-70 %.
•
It also restricts pool water from getting evaporated thus saving the amount of make up
water required.
•
It also reduces the chemical consumption of pool.
Materials used for making pool covers:
•
UV stabilized polyethylene.
•
UV stabilized polypropylene.
•
UV stabilized vinyl.
Pool covers can be:
•
Transparent
•
Opaque
•
Translucent
Modes of operating a pool cover:
•
Manually
•
Semi automatic using a motor driven reel system.
•
Automatic having permanently mounted reels.
26
Mechanism of working of a pool cover:
These covers are made up of tiny air pockets which hold the heat gathered from the sun. This
heat is then slowly released. These pockets help in heating the pool to its greatest depths.
These air pockets come in different shapes like diamond and circle shapes. Cover having
diamond pockets will hold more heat as these pockets will be closed together. Cover having
circular pockets will be further apart and will not hold so much heat as in case of diamond
pocket.
Figure 7: pool cover
The performance of a pool cover depends on:
•
Thickness of cover.
27
•
Colour of cover.
•
Shape of air pockets.
•
Efficiency of operating pool cover and its maintenance.
2 SOLAR SUN RINGS [22]
Solar rings are made of two sheets of heavyweight UV resistant vinyl. The upper air holds the
insulating air and it focuses sunlight on blue coloured lower layer. This blue layer absorbs
fifty percent of sunlight and converts it to heat. Rest of the sunlight passes through for deep
water heating. The air trapped acts as an insulating blanket at night and retains the heat.
These rings can decrease evaporation, help in heating the pool water and help save chemicals
required by the water.
These rings will help in reducing costs of heating pool and will prove economical in long run.
Figure 8: solar sun ring. [23]
28
2.3
PREVIOUS
WORK
DOE
O
SWIMMIG
POOL
HEATIG
BY
RESEARCHERS
BRAMBLEY AND WELLS (1983) [1]
They have suggested various equations to calculate the heat losses associated with a
swimming pool. They have developed equations to assess various losses like:
Convective heat loss:
qconv= h(Ts-Ta)
Evaporative heat loss:
qeva= (m*)*(hfg)
Radiative heat loss:
Qrad= σ(Tw4 – Ta4)A
Conductive heat loss:
Qcond= U*A*(Tw – Tg)
They have devised several ways to reduce cost of heating. They have analysed ventilation
rates, solar heating systems, pool covers to reduce costs in different conditions like when:
Tw>Ta or when: Ta>Tw.
29
MATUSKA et.al. (2009) [3]
They have developed Kolektor 2.2, a mathematical model and designing software, which is
an improvement over the previous designing models. This model is used for designing solar
flat plate collectors. The model developed has been experimentally validated for different
construction designs of tested solar collectors. After validation, this designing tool can be
used for designing and virtual prototyping of new flat plate solar collectors. A refrence solar
flat plate collector was used for analysis.
MISHRA (1993) [4]
In this paper, hybrid solar air and water heating systems have been developed. Performance
equations have been developed. Equations developed are for collection efficiency in terms of
design parameters for air and water heating systems. These equations have been
experimentally verified. Transient analysis for open and closed loop cycle has been done.
Techno-economic evaluation has been done for these systems keeping in mind the Indian
market.
ALKHAMIS et.al. (1992) [5]
Simulation software TRNSYS has been used for conducting feasibility studies of a solar
assisted heating system. A thermodynamic as well as an economic analysis has been done for
the Aquatic centre at University of Miami. The effect of collector area on different systems
30
and sub-systems was studied. Economic analysis was done by keeping in mind the fuel prices
and inflation.
SINGH et.al. (1989) [6]
A transient analysis of an indoor swimming pool has been done which is connected to a panel
of collectors. Based on this, an explicit equation was developed for the pool water
temperature. To validate the model, calculations were done for an Australian swimming pool
under active and passive mode of operation. The developed equation can be used for
optimization.
FRANCEY et.al. (1980) [7]
In this paper, the effect of using a pool cover on energy savings has been studied. Two
systems were compared, one with pool cover on it and one without a pool cover. Covers of
different material were used for experimenting and different effects were studied. Pool covers
were found to be economical and were effective in reducing heat loss.
LUMINOSU (2004) [8]
For constant maintenance of temperature and efficiency of solar collector, flow of the thermo
fluid needs to be modified. An analytical and numerical study has been done on the
temperature and efficiency equations. Experimental verifications for the numerical study
31
were done. The method developed allows the establishment of technical and constructive
parameters of a flat plate solar collector.
FRANCEY et.al. (1981) [9]
Solar radiation was measured and absorption characteristics of solar radiation were studied. A
number of optical tests were done on pool covers to determine the characteristics of different
types of pool covers. The transmission characteristics of pool covers were determined. It was
determined that pool covers were useful in maintaining elevated water temperature.
YADAV AND TIWARI (1987) [10]
In this paper, a transient analysis of swimming pool, with and without pool cover, with and
without heat exchanger has been done. For each of the above cases, equation for pool water
temperature has been determined. For testing the equations, experimental data was employed.
The experimental results were in good agreement with the numerical analysis.
HAAF et.al. (1994) [11]
In this paper, the general energy model was elaborated for open air swimming pools. In the
general model, parameters defined with the optimization model were integrated. The
developed model was validated with different swimming pools. The validated model was
integrated in a user friendly programme which can be used by design engineers.
32
KAYALI (1998) [12]
In this work, different types of domestic water heating systems are compared with each other.
These systems include thermosiphons, geysers, flat plate collectors and solar ponds. An
economic analysis has been done for all these and their annual total costs were compared. In
long term, solar based heating proved to be the most economical.
KIM et.al (2008) [13]
In this paper, thermal performance of a compound parabolic concentrator has been evaluated.
A numerical analysis was done for the simulation of experimental set up. Two types of
models of compound parabolic concentrator –stationary and tracking were studied and their
thermal efficiency was determined.
LEE et.al (2008) [14]
Optimization of heat pump design has been carried out in this paper. To reduce the cost,
swarm algorithm has been used for optimizing the heat pump. An indoor swimming pool has
been used for optimization and different continuous and discrete parameters were optimized.
33
34
EXPERIMETAL:
3.1 TABULATION OF TEMPERATURE DURING WINTERS.
To assess the temperature pattern during winter season, temperature of air above the pool and
pool temperature were recorded during the month of November at six different times in a day.
All temperatures are in degree Celsius.
Table 1: pool and air temperature at 6:00am and 6:40am for November.
DATE
Tw (6:00 am)
Ta (6:00am)
Tw (6:40am)
Ta (6:40am)
2
25
21
25
22
3
25
22
24
22
4
27
25
25
23
5
24
23
24
21
6
25
22
24
21
7
25
21
24
23
8
24
22
23
22
9
25
23
26
24
10
25
22
26
25
11
24
21
26
24
12
25
22
27
23
13
27
23
28
22
14
26
25
27
25
15
27
25
27
26
16
27
26
27
27
17
26
25
26
27
35
18
27
25
25
26
19
27
26
28
27
20
28
26
28
27
21
28
26
25
26
22
25
16
25
16
23
25
23
26
24
24
25
24
26
25
25
24
26
27
25
26
27
29
28
26
27
26
28
28
27
Table 2: pool and air temperature at 7:30am and 9:00am for November.
DATE
Tw (7:30am)
Ta (7:30am)
Tw (9:00am)
Ta (9:00am)
2
24
23
25
30
3
23
22
24
29
4
24
23
26
28
5
27
26
25
27
6
26
24
26
28
7
24
29
23
29
8
26
24
26
24
9
28
28
28
25
10
30
27
26
28
11
26
24
27
25
12
25
23
27
26
36
13
24
22
26
24
14
28
24
30
28
15
28
27
28
26
16
27
26
28
27
17
28
27
29
27
18
28
27
30
31
19
28
26
30
31
20
30
28
30
31
21
30
36
29
28
22
25
16
28
27
23
25
26
30
31
24
28
29
28
27
25
26
25
29
28
26
30
31
30
31
27
28
27
28
27
Table 3: pool and air temperature at 12:00 noon and 4:00pm for November.
DATE
Tw(12 noon)
Ta(12 noon)
Tw (4:00 pm)
Ta (4:00 pm)
2
26
31
25
22
3
25
32
24
21
4
27
32
26
22
5
28
31
25
21
37
6
29
30
25
22
7
28
31
27
22
8
27
25
28
23
9
29
31
29
28
10
30
32
-
-
11
29
31
30
31
12
32
28
28
30
13
32
30
27
25
14
31
30
28
29
15
30
32
27
25
16
30
31
28
27
17
29
30
27
28
18
32
35
27
25
19
30
28
28
26
20
30
32
28
26
21
30
32
28
27
22
30
28
26
30
23
31
32
27
29
24
30
39
26
24
25
30
32
28
26
26
35
35
29
30
27
32
35
28
30
38
3.2 EVALUATING LOSSES FROM SWIMMING POOL USING THE EXPERIMENTAL
DATA:
The above data was used in calculating the losses associated with the pool. Equations
developed by Brambley[1] were used in calculating the losses.
The equations used are:
Qconv = h*A*(Ts –Ta)
Qrad = σ*A*(Tw4 – Ta4)
Qcond = U*A*(Tw – T)
Qeva = (m*)*hfg*A
Qtotal = Qconv + Qrad + Qcond + Qeva
After calculating each loss and doing summation of all the losses, percentage contribution of
each loss to the total heat loss was calculated. Then pie charts were plotted to see the
contribution of each loss.
The obtained percentages of each loss were compared to the losses contribution as given in
literature.
39
3.3 DESIGN PARAMETERS FOR A HEATING SYSTEM BASED ON HEAT PUMPS:
A heating system has been designed with heat pumps as the heating source. Economic
analysis has been done using these. Heat pump takes electricity as input but utilize the
surrounding air to extract heat. It is one of the most efficient systems for heating but it
contributes in ozone layer depletion.
Specifications of heat pumps used in designing:
Different heat pumps were used for designing the system and for economic analysis.
Different heat pumps and their specifications are given below:
Table 4: specifications of heat pumps[24] used in designing the system and economic analysis.
MODEL NO.
KW RATING
COP
AWHNHP10N
12
4.17
WWHCNHP10 D.S.
12
6.25
AWHNHP12.5 N
13.5
4.63
WWHCNHP12.5 D.S.
13.5
6.96
AWHNHP25 N
26
4.75
WWHCNHP25 D.S.
26
7.15
AWHNHP50 N
52
4.75
WWHCNHP50 D.S.
52
7.6
Using the above details, economic analysis was carried out.
40
3.4 DESIGN OF SOLAR PANEL FOR HEATING SYSTEM BASED ON SOLAR WATER
HEATING (SWH)
A solar panel was designed to heat the water in swimming pool.
A picture of the designed solar panel is given below. In this design, plywood is used as a
base. A rectangular piece is attached to the plywood in the middle. Around this small centre
piece, a pipe of 1 inch has been coiled. Some part of the starting part of the coil has been
taken out. The end part of the coil is taken towards one side corner of the base. Thin wood
sticks have been used to keep the coiled pipe in place.
This is not a working model. No experiments have been conducted using this model. This
model represents the actual design layout of the solar panel intended to be used in heating.
Figure 9: design of the proposed solar panel.
41
3.5 DESIGN PARAMETERS USING GAS HEATERS FOR HEATING SWIMMING
POOL WATER
Gas heaters have been considered to heat the pool water. Models of different efficiency and
heat capacities have been considered. Details of them are given below.
Table 5: specifications of natural gas heaters used in designing and economic analysis.
Model no.
Rating
of
heater Input power (KW)
Efficiency (%)
(output) in Btu/hr
1
150,000
55
80
2
150,943
52
85
3
75472
26
85
4
34833
12
85
Economic analysis has been carried out on the above models of gas heaters and their
feasibility for pool water heating is discussed.
42
43
4.1 POOL WATER VOLUME CALCULATION
Length of pool = 50m
Width of pool = 22m
Depth of pool = 1.8m for first 25m of length which gradually decreases to
0.9m for the next 25m of length.
Figure 10: schematic diagram of swimming pool at NIT Rourkela.
Volume of pool = [(25*1.8288) + {0.5(1.8288 + 0.9144)}*25]*22
= 1760 m3 = volume of pool water
Area of the pool, A = 50*22 =1100 m2
44
4.2 CALCULATION FOR HEAT REQUIREMENT BY POOL FOR A 10 DEGREE RISE
IN TEMPERATURE
Density of water = 1000 kg/m3
Specific heat capacity of water = 4.18 KJ/(Kg*deg Celsius)
∆t = 10 deg Celsius.
Now , using the heat equation,
Q = m*Cp*∆t
m = (density of water)*(volume of water)
= 1000*1760
= 176*104 kg
Q = (176*104)*(4.18)*(10)
= 73,568,000 KJ
If a heating period of 6 hours is assumed, power required to raise the pool temperature is:
73,568,000/(6*60*60) = 3406KW
45
4.3 SAMPLE CALCULATION OF HEAT LOSSES USING EQUATIONS DEVELOPED
BY BRAMBLEY [1]
Data point chosen for calculation:
Date : 12th November
Time : 12:00 noon
Assumptions:
Air velocity above pool surface (υ) = 0.15 m/s
Overall heat transfer coefficient for conduction (U) = 0.57W/(m2*degree Celsius)
Evaporative heat loss:
Qeva = (m*)*hfg*A
m* = [(c1 + c2υ)/hfg]*[Pv,s – Pv,e]
c1 = 8.87*10-5 KW/(m2 * Pa)
c2 = 7.78*10-5 KJ/(m3 * Pa)
On 12th November at 12 noon:
Pool water temperature = 32 degree Celsius
Air temperature = 28 degree Celsius
Partial pressure of water at pool surface (Pv,s) = 4743 Pa
Vapour pressure of water far from surface of water (Pv,e) = 3780 Pa
46
Area of the pool (A) = 1100m2
Putting the values, we get:
Qeva = 106 KW
Convective heat loss:
Qconv = h*A*(Ts – Ta)
h = 3.1 + 4.1υ [15]
Ts = 32 degree Celsius
Ta = 28 degree Celsius
We get the convective heat loss as:
Qconv = 16.34 KW
Radiative heat loss:
Qrad = σ*A*(Tw4 – Ta4)
σ = 5.67*10-8 W/(m2 * K4)
Tw = 32 degree Celsius
Ta = 28 degree Celsius
Therefore, we get:
Qrad = 27 KW
47
Conductive heat loss:
Qcond = U*A*(Tw – Tg)
U = 0.57 W/(m2 * degree Celsius)
Tw = 32 degree Celsius
Tg = 28 degree Celsius
We get:
Qcond = 2.508 KW
Total losses
Qtotal = Qeva + Qconv + Qrad + Qcond
= 151.848 KW
% evaporative loss = (Qeva/Qtotal)*100 = 69.8%
% convective loss = (Qconv/Qtotal)*100 = 10.76%
% radiative loss = (Qrad/Qtotal)*100 = 17.78%
% conductive loss = (Qcond/Qtotal)*100 = 1.65%
48
4.4 SAMPLE CALCULATION FOR OPERATING COST OF A HEAT PUMP
Assumption: heating cycle = 6 hours
Pump model no: AWHNHP25 N
Power rating of the pump: 26 KW
COP: 4.75
Cost of electricity = 2.5 Rs/KWh
KW rating of heat pump = 26KW
Hours /day heat pump is to be used = 6 hrs
Daily operating cost = (2.5*26*6) = Rs 390/day
Days in a month heat pump is used = 30
Therefore, monthly operating cost = 390*30 = Rs 11,700 per month
Heat output given by 1 pump = 26*4.75 = 123.5 KW
Therefore, number of heat pumps of 26 KW rating (COP=4.75) required to raise the pool
water temperature by 10 degree Celsius = (3406/123.5) = 28 nos.
49
4.5 SAMPLE CALCULATION FOR OPERATING COST OF A GAS HEATER
Cost per therm of natural gas = 0.525 $/therm
(1therm = 105 Btu)
Btu/hr rating of natural gas heater = 150,000Btus/hr (=43.95 KW)
Efficiency of heater = 80% = 0.8
Therms/hr = (150,000/0.8)/105 = 1.875 therms/hr
(input energy = 150000/0.8 = 187500 Btu/hr = 55KW)
Hrs per day heater is used = 6 hrs
Daily operating cost = (0.525*1.875*6) = 5.9 $/day
Days in a month heater is used = 30
Monthly operating cost = (5.9*30) = 177 $/month
Assuming: 1$=50 Rs
Monthly operating cost = Rs 8850
No.of units required to raise the temperature of pool water by 10 degree Celsius in 6 hours =
3406/43.95 = 78
Total monthly operating cost of the whole natural gas heater installation = (78*8850) = 6,
90,300 Rs.
50
51
5.1 DESIGING OF HEATING SYSTEM BASED ON HEAT PUMPS
In this particular system design, heat pumps have been used as the heating device for raising
the temperature of the pool water. Different models of heat pump have been considered.
Operating cost per month has been determined for each model. The number of units of heat
pumps required to heat up the pool in 6 hours of each model has been calculated. Thus
economic feasibility of easily available heat pumps has been determined.
Below is a flowsheet showing the installation of heat pumps in the pumping and filtration
unit of swimming pool.
Figure 11: flowsheet showing heat pumps as heating medium.
52
5.2 DESIGNING OF HEATING SYSTEM BASED ON SOLAR ENERGY OR SWH
SYSTEM
To make full use of the abundant solar energy available in Rourkela, solar panel has been
designed. But this is not a 100% solar energy based heating system. The power required to
heat the pool in six hours for a ten degree temperature rise is 3406 KW. Only 50% of this
power required, i.e., 1703 KW will be generated by solar energy. The rest 50% power has to
come from some other source like conventional heaters. This is done to avoid total
dependence on solar energy and make the system more efficient. This hybrid system for
heating of pool water will prove to be economical as well as efficient.
A schematic diagram of set up of solar panel and their connectivity with pumping and
filtration is shown:
Figure 12: flowsheet of solar panel being used as heating medium.
53
5.3 DESIGNING OF HEATING SYSTEM BASED ON GAS HEATERS
Gas heaters are efficient in heating pool waters. But this is a costly method. Natural gas
heaters are available easily. A flowsheet below shows the heating system based on natural
gas heaters.
Figure 13: flowsheet showing natural gas heater being used as heating source.
54
55
RESULTS AND DISCUSSION
6.1
MOTHLY
VARIATIO
OF
POOL
WATER
AD
AMBIET
AIR
TEMPERATURE AT DIFFERET TIMES I A DAY:
Graphs have been plotted for the month of November showing the temperature variation of
both pool water and air at different timings for which readings were recorded. Some
observations are:
A wavy pattern was observed with small deviations from mean temperature.
Sharp peaks (up or downwards) were observed in some days.
Maximum 9 intersections (at 4:30pm) and minimum 1 intersection (at 6:00am) were seen
between the temp curve of pool water and air in a month.
35
30
25
temp of
water and
air in deg C
20
temp-water
15
temp-a
10
5
0
0
5
10
15
20
25
30
day of the month
Figure14: variation of pool water and air temp with each day of month at 6:00am
56
40
35
30
25
temp of air
and water in
deg C
20
temp-water
15
temp-a
10
5
0
0
5
10
15
20
25
30
day of the month
Figure 15: variation of pool water and air temp with each day of month at 7:30am
35
30
25
temp of
water and
air in deg C
20
15
temp-w
temp-a
10
5
0
0
5
10
15
20
25
30
day of the month
Figure16: variation of pool water and air temp with each day of month at 9:00am
57
45
40
35
30
temp of
water and air
in deg C
25
20
temp-w
15
temp-a
10
5
0
0
5
10
15
20
25
30
day of the month
Figure 17: variation of pool water and air temp with each day of month at 12:00 noon.
35
30
25
temp of
water and air
in deg C
20
temp-w
15
temp-a
10
5
0
0
5
10
15
20
25
30
day of the month
Figure 18: variation of pool water and air temp with each day of month at 4:00pm
58
6.2 DETERMIATIO OF LOSSES FROM TEMPERATURE DATA
Using the temperature data recorded, losses were calculated for 12:00 noon. Evaporative,
conductive, convective and radiative heat losses were calculated and percentage of each loss
was plotted in a pie chart.
Table 6: losses calculation at 12:00 noon
DATE
Qeva (KW)
Qcond (KW)
Qconv (KW)
Qrad (KW)
2
126
3.135
20.5
29
3
176
4.389
28.6
41
4
132
3.135
20.5
32
5
80
1.8
12.26
19
6
27
0.627
4
6.4
7
80
1.8
12.26
19
8
43
1.2
8
9
9
55
1.254
8
13.5
10
58
1.254
8
14.8
11
55
1.254
8
13.5
12
106
2.508
16.34
27
13
55
1.254
8
14.9
14
26
0.627
4
7.08
15
58
1.254
8
14.9
16
29
0.627
4
7
17
27
0.627
4
6.4
18
97
1.881
12.26
28.19
59
19
50
1.254
8
12.18
20
58
1.254
8
14.9
21
58
1.254
8
14.9
22
50
1.254
8
12.18
23
275
0.627
4
7.8
24
305
5.643
36.8
93.8
25
58
1.254
8
14.9
26
2
0
0
0
27
97
1.881
12.26
28.19
PIE CHARTS TO SHOW % DISTRIBUTION OF EACH LOSS:
To show the % contribution of each loss, pie charts have been made for some days at
12:00noon time.
% of total
14.7
Qeva
13
Qcond
Qconv
1.96
Qrad
70
Figure19: % contribution of each loss on 8th November.
60
% of total
17.78
Qeva
Qcond
10.76
Qconv
1.65
Qrad
69.8
Figure 20:% contribution of each loss on 12th November.
% of total
18.8
Qeva
Qcond
10
Qconv
1.58
Qrad
69.5
Figure 21:% contribution of each loss on 13th November.
61
% of total
18.77
Qeva
Qcond
10.6
Qconv
1.66
Qrad
68.9
Figure 22:% contribution of each loss on 14th November.
% of total
17
Qeva
Qcond
11.2
Qconv
1.75
Qrad
70
Figure 23:% contribution of each loss on 19th November.
62
Some observations from the heat loss data:
The evaporation heat loss was about 70 %.
The radiative heat loss varied between 14-18 %.
The convective heat loss varied between 10-13%.
The conductive heat loss was less than 2%.
The above observations are in full agreement with the data given in the literature. Hence heat
loss profile has been calculated successfully for the swimming pool at NIT Rourkela.
6.3 ECOOMIC AALYSIS OF HEAT PUMP BASED WATER HEATIG
SYSTEMS
Different heat pump models were considered to heat the pool water. Each KW rating model
has two variants, one with low COP and the other with a high COP. Monthly operating costs
have been calculated for each model and number of units required for each model to raise the
temperature of pool water by 10 degree Celsius for 6 hours heating period have been
estimated.
63
The table below shows the results:
Table 7 :cost analysis and no. Of unit required for each model
MODEL
KW
COP
HEAT
MONTHLY
UNITS
DELIVERED OPERATING REQUIRED
RATING
(KW)
COST(Rs)
FOR 1 UNIT
AWHNHP10 N
12
4.17
50.04
5400
68
WWHCNHP10
12
6.25
75
5400
46
13.5
4.63
62.505
6075
55
WWHCNHP12.5 13.5
6.96
93.96
6075
37
D.S.
AWHNHP12.5
N
D.S.
AWHNHP25 N
26
4.75
123.5
11,700
28
WWHCNHP25
26
7.15
185.9
11,700
19
AWHNHP50 N
52
4.75
247
23,400
14
WWHCNHP50
52
7.6
395.2
23,400
9
D.S.
D.S.
Though the operating cost of a model with two different COP is same, the cost price and heat
output will be different. For a same KW rating model, higher COP model will deliver more
heat and it will be costlier than low COP model. The purchasing and installation cost of each
model will be constant and their monthly operating cost will vary according to existing
electricity charges, which vary from place to place and also on mode of electricity generated.
64
monthly operating cost (Rs)
25000
20000
15000
monthly operating
cost( Rs)
10000
5000
0
0
10
20
30
40
50
60
kilowatt rating
Figure 24: plot of KW rating Vs monthly operating cost.
no of units of heat pumps req
50
45
40
35
no of units
of heat
pump req
30
25
20
15
10
5
0
0
10
20
30
kilowatt rating
Figure 25: plot of KW rating Vs no. of units required.
65
40
50
60
As we can see from the plot, monthly operating cost increases linearly with increase in KW
rating of the heat pump.
Now, total cost = fixed cost + operating cost
Here, fixed cost is equipment plus installation cost.
Therefore, for two models with same KW rating and different COP, the one having higher
COP will have more total cost than the one with lower COP. We also see that as the KW
rating increases, no. of units required of the model decreases. But also cost price of each
model increases with increasing KW rating and COP.
6.4 ECOOMIC AALYSIS OF ATURAL GAS HEATER BASED WATER
HEATIG SYSTEM
Cost analysis has been carried out for different rating and efficiency models of natural gas
heaters. The details are listed below in the form of a table:
Table 8 :monthly operating costs and no. of units required for each model of gas heater
Model .no
Input power Efficiency
Heat
Monthly
No. of units
(KW)
delivered
operating
required
(output)
in costs for 1
(%)
KW
unit (Rs)
1
55
80
43.95
8850
78
2
52
85
44.22
8400
77
3
26
85
22
4200
155
4
12
85
10.2
1935
334
66
We see that as the KW rating increases, no of units required decreases and monthly cost also
increases. This is shown in the graph below:
10000
9000
8000
7000
monthly
operating
costs(Rs) and
no of units req
6000
5000
4000
units req
3000
cost
2000
1000
0
0
20
40
60
KW rating (input)
Figure 26 : KW rating Vs monthly operating costs and no. of units required.
6.5 COST COMPARISO BETWEE HEAT PUMPS AD ATURAL GAS
HEATERS
Heat pumps and natural gas heaters are both a viable option from efficiency point of view.
But the final decision to choose will depend on which one is more economically viable. A
comparison between heat pump and natural gas heaters has been done in terms of cost and
no. of units required.
67
Table 9 : cost comparison between heat pumps and natural gas heaters.
KW
Monthly
Monthly
rating
operating
operating
(input
cost (Rs)
(Rs)
No
of No
cost units
required
12
5400
NG heater
1935
Annual
operating
units
operating
required
cost (Rs) cost (Rs)
power)
Heat pump
of Annual
*105
*105
NG heater
Heat
NG
Heat
pump
heater
pump
68
334
44
77.55
28
155
39.3
78.12
9
77
25.27
77.6
(COP=4.17) (efficiency=0.8)
26
11700
4200
(COP=4.75) (efficiency=0.8)
52
23400
8400
(COP=7.6)
(efficiency=0.8)
As we can see from the data, number of units required in case of natural gas heaters is too
high. Even for high rating natural gas heaters, no. of units required is too large. It is very
difficult to install so many heaters.
68
90
80
70
annual
operating cost
of heat pump
and natural gas
heaters (Rs)
60
50
40
HP cost
30
Ngcost
20
10
0
0
20
40
60
KW rating (input)
Figure 27 : cost comparison between heat pumps and natural gas heaters.
From the table we see that though the monthly operating cost of a single natural gas heater is
less than a heat pump for the same rating, but since a large number of natural gas heaters is
required, the annual operating cost of natural gas heaters shoot up as compared to heat
pumps. The operating cost of natural gas heaters is 1.8-3 times more than heat pumps
annually. Therefore economically, heat pumps are a better option than natural gas heaters.
6.6 DESIGIG OF WATER HEATIG SYSTEM BASED O SOLAR EERGY
A design has been proposed to heat the pool water by using a solar heating system. A solar
panel is made by coiling pipe on a wooden base. Inlet and outlet pipes from each solar panel
are connected to respective main headers from where the pool water is distributed.
A schematic diagram of the solar panel is shown
69
Figure 28: flow sheet showing the connections of the solar panel and its basic design.
This design can be used to raise 50% of the heat requirement. The other 50% can come from
conventional heaters. In this way we can achieve a balanced system giving both credibility
and economic viability to pool heating.
This system will reduce the operating cost of conventional heaters by half. Renewable source
of energy is being utilized which will decrease the dependence on fossil fuels.
70
71
CONCLUSIONS:
•
Temperature variation of pool water and air above the pool at different times was
recorded for the month of November. Graphs were plotted based on this data which
showed the intersection of two temperature curves at least once a day.
•
Based on the temperature data obtained, various losses associated with the pool were
calculated and percentage of each loss with respect to the total loss was shown in
form of pie charts.
•
About 70%loss was evaporative, about 18% was radiative loss, convective loss was
about 10% and conductive loss contributed less than 2%. This is in complete
agreement with the literature data.
•
Three heating systems based on different heating sources are proposed:
•
Cost analysis of heat pump as heating source was done. Heat pumps are very efficient
but they are very costly and are a threat to environment.
•
Cost analysis of natural gas based heater was done. Though they are effective heaters,
they are 2-3 times costlier than heat pumps and natural gas is a renewable source of
energy, thus its use as a heating medium in swimming pool should be avoided.
•
A system based on 50% solar energy and 50% conventional heaters is proposed. A
design of solar panel to be used is provided. In this way, we make use of the abundant
solar energy and also make the system efficient by incorporating conventional heaters.
This system will prove cost effective in long run.
72
SCOPE FOR FUTURE WORK:
•
For the whole winter season i.e., from October to February, temperature of the pool
water, temperature of air above the pool, humidity and air velocity can be recorded.
Using this data, mathematical equations and models can be developed for the
swimming pools located in tropical climate like that of Rourkela.
•
Experiment can be done on the proposed solar panel. By using no of panels and
connecting them in series, one can see by using a given flow rate, how much
temperature rise is possible. Based on the experimental results, power generated by
each panel and size of each panel can be calculated. Number of panels required can be
calculated and thus these panels can be fabricated for heating swimming pool water.
•
A swimming pool cover can be installed over the pool to reduce the losses due to
evaporation. This will reduce the heat requirement and will thereby reduce the cost of
heating.
73
REFERECES:
[1] Brambley M.R. and Wells S.E. Energy conservation measures for indoor swimming
pools, Energy, 8(6), 1983, pp. 403-418.
[2] Technical manual. Swimming pool operation and maintenance, TM 5-662, 28 feb 1986,
chapter 14-swimming pool heating.
[3] Matuska T., Zmrhal V. and Metzger J.Detailed modelling of solar flat collectors with
design tool kolektor 2.2, eleventh international IBPSA conference, Glasglow, Scotland, july
27-30, 2009.
[4] Misra R.S. Evaluation of economic and thermal performance of closed loop solar hybrid
air and water heating systems for Indian climates, Energy Convers, Mgmt Vol 34(5), 1993,
pp. 363-372.
[5] Alkhamis A.I. and Sherif S.A. Performance analysis of a solar assisted swimming pool
heating system, Energy, Vol.17(12), 1992, pp.1165-1172.
[6] Singh M., Tiwari G.N. and Yadav Y.P. Solar energy utilization for heating of indoor
swimming pool, Energy Convers, Mgmt .Vol. 29(4), 1989, pp. 239-244.
[7] Francey J.L.A, Golding. P and Clarke. R. Low cost solar heating of community pools
using pool covers, Solar Energy, Vol 25, 1980, pp. 407-416.
[8] Luminosu I. Flat plate solar collector technical constructive parameters determination by
numerical calculation, considering the temperature criterion, Romanian Reports in Physics,
Vol.56(1), 2004, pp. 13-19.
[9] Francey J.L.A. and Golding P. The optical characteristics of swimming pool covers used
for direct solar heating, Solar Energy, Vol 26, 1981, pp. 259-263.
[10] Yadav Y.P. and Tiwari G.N. Analytical model of solar swimming pool : transient
approach, Energy Convers, Mgmt. Vol 27(1), 1987, pp.49-54.
[11] Haaf W., Luboschik U. and Tesche B.Solar swimming pool heating: description of a
validated model, Solar Energy, Vol.53(1),1994, pp. 41-46.
[12] Kayali .R. Economic analysis and comparison of two solar energy systems with
domestic water heating systems, Tr.J. of Physics, Vol 22, 1998, pp. 489-496.
74
[13] Kim Y., Han GY. and Seo T.An evaluation of thermal performance of CPC solar
collector, International communications in heat and mass transfer, Vol35(4), 2008, pp.446457.
[14] Lee WS. and Kung CK. Optimization of heat pump system in indoor swimming pool
using particle swarm algorithm, Applied thermal engineering, Vol.28(13),2008, pp.16471653.
[15] Czarnecki J.T. Swimming pool heating by solar energy, CSIRO division of Mechanical
Engineering, Technical Report, TR 19, 1978.
[16] www.learnaboutpools.com
[17] www.swimmingpoolsetc.com
[18] www.jacksons-camping.co.uk
[19] www.nrel.gov
[20] www.swimmingpoolheaters.blogspot.com
[21] www.coolace.com
[22] www.solarsunrings.com
[23] www.poolsinc.com
[24] www.nationalheatpumps.com
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