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Chapter-1
1. Introduction
We use solar energy in our life in different ways. Solar energy can be used for heating as
well as cooling purposes i.e., provide refrigeration for food preservation and comfort cooling,
cooking, electricity, etc. The solar energy for cooling can be either provide refrigeration for
food preservation & comfort cooling. Solar heating is more popular as compared to the solar
heating.
We can store solar energy for air conditioning in two different ways - thermally and in
storage batteries with the help of photo voltaic panels. In photo voltaic system we use photo
voltaic panels to convert the solar radiations in DC electricity. Photo voltaic panels have two
main advantages. First, they can use as utility grid for backup power in cloudy days. Second,
they can use as conventionally electrically driven air conditioning system, which is widely
available and inexpensive.
But there are three major disadvantages attributes of the photovoltaic system that are- First,
electricity from the solar cells are very expensive because of the high cost of the solar panels.
Second, space needed for required air conditioning system is large. Third is the panels provides
no energy storage that creates problem in night and cloudy days. There is a mismatch between
supply of needed and power of demand. Because the solar panels supplies peak load at noon &
the demand of the air conditioning at peak is after several hours. This is also a negative point
for the system. This point greatly reduces the value of the system in reducing peak power
demand to the utility.
We can use batteries as the storage but they are expensive, require periodic replacement
and normally use toxic and/or corrosive materials. These problems prevented the use of
photovoltaic system.
Thermally driven system uses different approach. In thermally driven system we use solar
energy (heat) from the sun to drive an air conditioner. Flat plate solar collector is used to take
the heat and supply to absorption system. Natural gas or other fuels can be used as back-up
heat storage in peak loads and/or cloudy days.
In this system, solar panels are not used and this is a main advantage that this system is
inexpensive. In addition, there is no economically viable way for storing solar energy with this
approach of the thermally driven air conditioning system. For this reason they have seen very
little.

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1.1 Air Conditioning:
The air conditioning is the branch of mechanical engineering which deals with the study
of air i.e. supplying and maintaining the desirable internal atmospheric condition for
human comfort, irrespective of external conditions and the system which effectively
controls these conditions to produce the desired effects on occupants of the space is known
as air conditioning system.
1.2 Available Refrigeration Cycles:
1.2.1 Vapour Compression Refrigeration Cycle
1.2.2 Vapour Absorption Refrigeration Cycle
1.2.1 Vapour Compression Refrigeration Cycle:
A vapour compression refrigeration system we use refrigerant as a working substance,
which transfers the heat energy between evaporator and condenser. The refrigerant does not
leave the system, it circulated throughout the system.
Generally Ammonia, Carbon Dioxide and Sulphur Dioxide are used as Refrigerant. In
the VCR the refrigerant evaporates and condenses in evaporator and condenser respectively.
In evaporating, the refrigerant absorbs its latent heat from brine which is used for circulating it
around the cold chamber. While condensing, the refrigerant gives out its latent heat to the
circulating water of the cooler (Figure. 1).
Condenser
Evaporator
Compressor
Expansion
Valve
Valve
1
2
3
4
Fig.1.1.1 Vapour Compression Cycle

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1.2.2 Vapour Absorption Refrigeration Cycle:
In refrigeration cycle, it is required to change the condition of refrigerant for
refrigeration. In vapour compression system we use mechanical energy in order to change the
condition. But, in the vapour absorption system we use heat energy instead of mechanical
energy.
To achieve this in Vapour Absorption System we replace the compressor by an
absorber, a pump, a generator and a pressure reducing valve. These components in vapour
absorption system perform the same function as that of a compressor in vapour compression
system. In this system two types of solutions are circulated in two different circuits. Types of
the solution are – Strong Solution & Weak Solution.
The vapour refrigerant form the evaporator is drawn into an absorber where it is absorb
by the weak solution of the refrigerant forming a strong solution. This strong solution is
pumped to the generator. Generator is used to heat the strong solution with the help of external
heat source. During the heating process, the vapour refrigerant is driven off by the solution and
enters into the condenser where it is liquefied. The liquid refrigerant then flows into the
evaporator and thus the cycle is completed.
Condenser
Evaporator
Expansion Valve
Generator
Absorber
Pump
Fig.1.2.2 Vapour Absorption Cycle

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1.3 Solar Air Conditioning:
Solar air condition can be done in four ways are given below-
1.3.1 Solar Air Conditioning using Desiccants
1.3.2 Passive Solar Cooling
1.3.3 Solar Thermal Cooling
1.3.4 Photovoltaic Solar Cooling
1.3.1 Solar A/C using Desiccants:
In this system we use desiccants for dehumidify the air by passing the air over the solid
desiccant or through the spray of liquid desiccant. The desiccant is used to draw moisture from
the air and make it more comfortable. In this system regeneration of desiccant is necessary and
it is done by solar thermal energy.
The solar heat energy has drawn the excess quantity of moisture from desiccant for
regeneration process. In this system we use solar collector for providing energy to the
desiccant.
1.3.2 Passive Solar Cooling:
In this system we don’t use directly solar energy for conditioning process. We use solar
energy in indirect way. We design the buildings, homes in such a manner that we minimize the
heat transfer of solar energy into a building in summer.
1.3.3 Solar Thermal Cooling:
This is a closed cycle system, in which thermally driven sorption chiller produce chilled
water for use in space conditioning equipment. This system can be efficiently use in summer
for cooling, and also heat domestic hot water and buildings in the summer. Specially designed
Solar Flat Plate Collector can be used for chillers requires water of at least 88° C.
1.3.4 Photovoltaic Solar Cooling:
Photo voltaic system is very expensive and need large grid area for provide sufficient
electricity to drive air conditioning system.

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Till now we have discussed about the four types of cooling methods.
The advantages of Solar Cooling by Desiccants over those methods are as follows:-
 Low cost.
 Low collector temperature.
 Low collector size.
 Can be used in night & cloudy conditions.
1.3 Solar Power Benefits:
 The demand of energy is increasing day by day. The requirement of the energy is very high at
peak loads. In summer the Solar Energy is very plentiful and the load supply is low. We should
use non-conventional energy sources. Because of high demand of energy it would be more
sense to use solar powered air conditioning units. It is more affordable compared to other
sources. This is the reason for our project title ‘Solar Air Dehumidifier’ chosen by us. In most
cases A/C units are used in mostly sunny hot weather.
 Cost is efficient to use.
1.5 Solar Collector:
The flat plate solar collector is used. It is like a shallow pool of liquid. These are made
of round plastic plates covered with 4-Mill black polyethylene. It is used to store thermal energy
and balance the Calcium Chloride solution. The flow of air over the collector is Natural
Convection. The speed of wind is generally less than 10 mph. Copper tubes are used for better
heat transfer.

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1.6 Heat Exchanger:
Heat exchanger is used to transfer the heat from one fluid to another by direct or indirect
contact. In our project we use two types of heat exchanger. First is Liquid to Liquid indirect
contact type heat exchanger in which fluids transfer the heat from each other without any
physical contact. Second is Air to Liquid direct contact type heat exchanger in which both are
in direct contact physically and transferring heat.
Fig.1.5.1 Flat Plate Solar Collector

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Thermal resistance should be kept small. Sealing of heat exchanger is very difficult. Small air
gap cause thermal resistance.
1.7 Desiccants:
Desiccants are the materials used to absorb water or moisture. It is also used for
dehumidification process. If air flow over or passing through the desiccant, the desiccant will
absorb moisture from air. Most common types of desiccants are Silica Gel, Calcium Chloride,
activated Carbon Zeolites, Lithium Chloride and Lithium Bromide.
Types of desiccants:
a. Solid desiccants(ex-Silica gel)
b. Liquid desiccants(ex-Calcium Chloride)
Calcium Chloride is the cheapest and best choice for the desiccant system. Other
advantages are that it has strong affinity for water, and relative ease of refrigeration. In anything
contact with Calcium Chloride needs to be made of glass or plastics due to corrosive property
of CaCl2. Most important property is that Calcium Chloride doesn’t freeze easily unlike the
magnesium chloride brine.
Solid desiccants can be used for dehumidification process but the pressure drop in this is
higher as compared to the liquid desiccant humidifier. Silica gel is a good example of solid
desiccant. In this air is passing over the solid desiccant wheel and the wheel adsorbs the
Fig.1.6.1 Counter Flow Indirect Contact Type Heat Exchanger

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moisture from the air. After adsorption the wheel becomes wet and the adsorbed moisture is be
removed by the help of other fan. The desiccant wheel has large surface area and is bulky too.
Here our objective is low cost
System with Lithium Chloride must work with very low pressure and requires large heat
exchanger surface. This will be resulting the system very expensive (Lithium Chloride).
Liquid desiccants have many advantages over the solid desiccants like–the desiccant is
heated up to dry off moisture, significant heat may remain in hot, dried solution. In the case of
solid desiccant system, it is hard to recover this heat. With liquid desiccants we can easily do
regeneration process.
We can also heat up the coming solution from the concentrator to the conditioner with the
help of counter flow heat exchanger.
Calcium Chloride is non-toxic, non-flammable and widely available in market & these
properties make it a good desiccant for dehumidification.

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Chapter-2
2. Literature Review
 Experimental studies have been carried out on liquid-desiccant air conditioner by
Lowenstein et al. (2006), in which Lithium Chloride and water solution was used as
desiccant. It was found that, the minimum pressure drops was obtained for low-flow liquid-
desiccant conditioner compared to other two conditioners and the temperature of air
delivered was lower for the same conditioner.
 Madhukeswaran and Parkash (2012) experimentally investigated the effect of different
coatings on performance of flat plate solar collector. It was found that, the maximum
temperature was obtained for black chrome coating compared to other two coatings and the
thermal efficiency of collector was highest for the same coating. They optimized the tilt
angle of the flat plate collector.
 Anmim et al. (2006) studied the Liquid Desiccant Dehumidifier with cooling capacity using
compression heat pump system. They have selected Lithium Chloride as refrigerant. It was
found that, the water condensation rate increases with increasing desiccant flow rate, air
inlet humidity ratio and desiccant inlet concentration. It changes very little with air inlet
temperature and desiccant inlet temperature.
 Experimental studies have been carried out on Evaporative Air Coolers coupled with Solar
Water Heater by Alosaimy (2013), in which Calcium Chloride and water solution was used
as desiccant. It was found that, desiccant minimum temperature was proportional to the
humidity potential between the indoor and outdoor conditions (temperature and humidity).
The experimental results were show that, Calcium Chloride solution with 30%
concentration can be regenerated up to 48% using solar energy.
 Experimental studies have been carried out on a liquid-desiccant air dehumidifier by
Bakhtiar et al. (2011), in which Lithium Chloride was used as desiccant. It was found that,
the higher air velocity was obtained faster air dehumidification and the higher desiccant
flow obtained larger effectiveness but effectiveness slowly came down after some time of
experiment.

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 Kishore and Dilip (2013) experimentally analyzed the liquid desiccant dehumidifier, in
which Calcium Chloride was used as desiccant. It was found that,
1. As the regeneration temperature was increased, moisture absorbing capacity of air was
increased.
2. As the regeneration temperature was increased, the dehumidification rate in the absorber
was increased.
3. The moisture removal rate was increased with the increasing in regeneration.
4. As the inlet temperature of desiccant (absorber) was increased, the dehumidification was
reduced in the absorber, indicated the reduction in moisture removal capacity.

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Chapter-3
3. Methodology
3.1 Principle of Solar Cooling:
Solar air cooler is used to dehumidify the air with
cooling by the evaporation of water. The dehumidification system consist of a conditioner to
dry the outside air taken into the room to replace that exhausted for ventilation purposed and
a concentrator(re-generator) which transfers the moisture from the diluted liquid desiccant to
exhaust air.
In the conditioner, outside air is passed through a spray
of desiccant where it is dried. The heat of condensation released there is removed by the coil
containing cold water. This supply of cool and dry air then enters the room by the fan or
conventional air conditioning system.
The liquid desiccant is continuously pumped between the conditioner and the concentrator
through a liquid to liquid heat exchanger.
In the concentrator the desiccant is sprayed on coils
heated by solar system. The water evaporated from the desiccant is in the process is transferred
to the air being exhausted from the room.
The basic solar system consists of solar collector and
storage tank. Solar collector can be used as a storage tank. Solar collector is used to store solar
energy in the form of thermal energy.

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3.2 Solar Collector:
Solar collector is used as a heat source which converts
the solar energy into thermal energy or heat energy. This heat energy is used for the removing
the extracted moisture from the desiccant. It is necessary for mass balancing. Solar collector is
made of steel. It can be also works as storage tank.
HEAT
STORAGE
ROOM
CONCENTRATOR
CONDITIONER
OUTSID
E AIR
(HOT &
WET)
EXHAUST AIR
(HOT & WET)
SOLAR COLLECTOR
SOLAR RAYS
EXHAUST AIR
(WARM &
DRY)
SUPPLY AIR
(COOL & DRY)
Fig. 3.1.1 Principle of Solar Air Cooling

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The heat energy coming from the sun is absorbed by
the absorber plates and liquid pipes in which fluid is flowing. For minimum get back of solar
rays from collector we use a glass plate which is covered at the top. The size of the collector
for our project is 60x60x15 cm. The absorber plate material is used as copper. Tube material
is also copper. Rockwool is used for the insulation of solar collector. The dimension of the
inside tube is 1 inch and 6 tubes are used. The design of solar collector is like fin and tube type.
The thickness of the absorber plate is 26 gauges. The solar collector is designed for standard
dimension for as per the requirement of heat energy or temperature.
3.3 Heat Exchanger:
Two types of heat exchangers are used in the system.
3.3.1 Direct contact type (liquid to air) heat exchanger.
3.3.2 Indirect contact type (liquid to liquid) heat exchanger.
3.3.1 Direct Contact Type:
In direct contact type Heat Exchanger both fluids come
into direct contact physically and heat transfer takes place. This heat exchanger is
used for absorption and dehumidification.
3.3.2 Indirect Contact Type:
In indirect contact type Heat Exchanger, fluids do not
come into directly. The heat transfer takes place in indirect contact manner. This
heat exchanger is used for transfer heat from the hot & strong desiccant leaving the
regenerator to the cool & weak desiccant flowing to the regenerator. It performs a
dual function. It is used for preheating the weak desiccant for regenerator and pre-
cooling the strong desiccant for conditioner.
3.4 Fans or Blowers:
Fans can be considered as a mechanical device used to
pump gases/air. Fans are used to supply or deliver air. Configuration of the fan depends
on the mass flow rate and density (function of pressure and temperature). We can use
blower (capacity-2.2 m3/minute) for high pressures.

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3.5 Pipes:
Pipes are used to circulate the desiccant in the circuits.
Plastic pipes (UPVC) are used for our project. They are inexpensive and easily
available in market. The size of the pipe is 16mm.
3.6 Pumps:
Centrifugal Pumps are used to supply the desiccant at
desired height. In our project, we are using small water pump which are being used in
Domestic Air Cooler.

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Chapter-4
4 Experimental Setup
4.1 Description:
A schematic diagram of experimental set-up is shown
in Fig. 4.1.1. In the set-up, two direct-contact type heat-exchangers (towers) are used for
dehumidification and re-generation process. The construction of both heat exchangers is
identical. These heat exchanger are made of fiber reinforced plastic and it has a constant height
of 120 cm. Packing is done using Cellulose Pads for a height of 30 cm. At the bottom of both
the towers a collection tank (Desert Cooler Bottom Tank) each for storage of the liquid
desiccant is provided. Sensors are used for measuring the temperature of desiccants as shown
in figure. Thermometer can be used for measuring the temperature. Pumps are placed between
the outlet of towers and the spraying circuit. Three pumps are used for pumping the desiccant
between tanks and Towers & Regenerator Tank and Solar Collector. Demister pads are placed
at the top of the towers to eliminate desiccant carry over through the air stream.
Devices Operating Range Fluid Uncertainty
Thermocouple Type
Thermometers
-200 to 350ºC Air and Liquid ±0.1732
Capacitive Probe Type
Hygrometer
0 to 100%
RH
Air ±0.1732
Vane Type
Anemometer
0 to 10
m/s
Air ±0.1732
Electronic Weighting
Machine
0 to 1000 gm Liquid ±0.1732
Table 4.1.1 Specifications of Measuring Devices

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WEAK SOLUTION
STRONG SOLUTION
DESICCANT SAMPLING
HYGROMETER
THERMOCOUPLE
REGENERATORABSORBER
HEAT
EXCHANGER
HEATING
TANK
COOLING
TANK
PACKING
DEMISTER
PADS
AIR
INLET
AIR
INLET
AIR OUTLETAIR OUTLET

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Fig. 4.1.1 Schematic Diagram of Experimental Setup
Fig. 4.1.2 Experimental Setup developed in Laboratory UCE
The experimental Setup developed for our project is shown in the above Fig.4.1.2. It mainly
consist of two towers, pumps, demister pads, fans, control valves, solar collector.
The specifications and description of the components used in the setup are discussed below.

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4.2 Design and Specification of Components
4.2.1. Tanks:
 Heating Tank:
Material-Sheet Metal
Width-83cm
Breadth-83cm
Height-20cm
Nos. 1
Heating tank is used to store hot desiccant which is
being used for the regeneration process in regenerator. The heat energy is generated using Solar
Energy. This tank supports the Absorber. The Desiccant solution from the Absorber is collected
in the Heating Tank and is heated with the help of solar energy received from the Solar
Collector. A pump is placed between the Heating Tank and Regenerator for pumping the
Desiccant.
 Cooling Tank:
Material-Sheet Metal
Width-70cm
Breadth-70cm
Height-20cm
Nos. 1
Cooling tank is used to store cooled desiccant which is
used in Absorber for the moisture absorption process. Desiccant solution from the Regenerator
is collected in the Cooling Tank. It is cooled by the cooling medium and supplied to the
Absorber with the help of pump, which is placed between Cooling Tank and Absorber.
4.2.2 Towers(Regenerator and Absorber):
Material-Fiber Reinforced Plastic Sheet
Height-120cm
Diameter-28cm
Nos. 2
Towers are used as direct contact type heat exchangers
for the Absorber and Regenerator. Both towers are identical and are made of Fiber Reinforced

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Plastic. The height of the tower is 120cm and diameter is 28cm. A slot of 10x10cm is provided
at the lower side of the tower for inlet air. The towers for Regenerator and Absorber are shown
in Fig. 4.2.2.1.
4.2.3 Packing:
Material-Cellulose Pads
Height-30cm
Diameter-28cm
Nos. 2 (For Absorber and Regenerator)
Cellulose Pad is used as packing material for a height
of 30cm. It is light in weight and having good surface area for the air and desiccant contact.
The diameter of the pad is equal to the tower diameter. Cellulose Pads are shown in Fig. 4.2.3.1.
Regenerator
Absorber
Fig. 4.2.2 Regenerator and Absorber

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4.2.4 Pump:
Voltage- 220-240V
Frequency-50Hz
Power-18W
Pumping Height (Maximum)-153cm (5ft)
Output-1800Ltr/Hr
Nos. 3
Centrifugal Desert Pump is used for pumping the
desiccant between absorber and regenerator and solar collector. The image of the pump used
in the setup is shown in Fig. 4.2.4.1.
Fig. 4.2.3 Packing of Cellulose Pads (Front and Top View)

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4.2.5 Pipes:
ASTM-D-2467
Material-UPVC
Inner Diameter-1.60cm
Outer Diameter-2.25cm
Nos. As per the connections between components and Space for Setup.
Length required for the Setup-20ft
Pipes are used to circulate the desiccant between
components. The standard size of the pipe is ½ inch used.
4.2.6 Flow Control Valve:
ASTM-D-2467
Material-UPVC
Inner Diameter-2.250cm
Outer Diameter-3.50cm
Nos. 3
Fig. 4.2.4 Centrifugal Pump

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Three flow control valves are used to controlling the
flow of desiccant. It is shown in Fig. 4.2.6.1.
4.2.7 Nipples:
Material-Plastic
Inner Diameter-1.5cm
Nos. 5
Nipples are used to connect the loose pipes to the
UPVC pipes and Pump lines. It is shown in above Fig. 4.2.7.1.
Fig. 4.2.6 Flow Control Valve
Fig. 4.2.7 Nipple of Joining Loose pipe and UPVC with the help of Union

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4.2.8 Union:
ASTM-D-2467
Material-UPVC
Inner Diameter-2.54cm
Nos. 2
Unions are used to join two pipes. The size of the union
is decided as per the size of the pipe and it is given above. It is shown in the Fig. 4.2.8.1.
4.2.9 Taps:
Material-UPVC
Diameter-1.50cm
Nos. 2
Taps are used for sampling of the desiccant. Two half
round taps are used for Absorber and Regenerator. It is shown in Fig. 4.2.9.1.
Fig. 4.2.8 Union
Fig. 4.2.9 Tap (Half Round Tap)

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4.2.10 Elbow:
ASTM-D-2467
Material-CPVC
Inner Diameter-1.60cm
3/4”x1/2”
Nos. 6
Elbow are used to join the pipes at right angles. It is
shown in Fig. 4.2.10.1.
4.2.11 T-Joint:
ASTM-D-2467
Material-UPVC
Type-Brass Thread
Inner Diameter-1.60cm
Nos. 2
T-Joint is shown in Fig. 4.2.11.1. It is used to connect
the tap between desiccant lines. The taps are used to sampling the desiccant used to measure
the concentration of the desiccant. The thread is provide to join the tap. Brass T-Joint is used
in our project of the standard size given above.
Fig. 4.2.10 Elbow

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4.2.12 Fans:
Sweep-230mm
Power input-42W
Speed (max)-1400rpm
Air Delivery-700cmh
Rated Voltage-230V
Rated Frequency-50Hz
Noise Level– 42 to 45db
Nos. 2
Fans are used for transferring air from the tower to the
outlet. Two fans are used for Regenerator and Absorber and is shown in Fig.4.2.12.
Fig. 4.2.11 T-Joint
Fig. 4.2.12 Fan (Top View of the Tower)

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4.2.13 Solar Collector:
Type- Flat Plate
Absorbing Tube Material-Copper
Sheet Material-Galvanized Iron Sheet
Insulation Material-Glass Wool
No. of Glass Covers-02
Flat plate solar collector is used to convert the solar
energy into thermal energy. Copper tubes is used for absorbing tube of 16mm diameter. It is
like a shallow pool of liquid. Collector is shown in Fig.4.2.13.1.
Collector Dimension (Inner) 50x50x10cm
(Outer) 60x60x15cm
4.2.14 Demister Pads:
Demister pads are used to extract moisture form the air.
The diameter of the pad is 25cm and the width is 5cm. Two pads are used for both towers.
Stainless Steel is used for the wire material. Demister pad is shown in Fig.4.2.14.1.
Type-Air type of Wire Netting
Material-Stainless Steel
Diameter-25cm
Width-5cm
Fig. 4.2.13 Flat Plate Solar Collector

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4.3 Interconnection Between Components:
The outlet of the Absorber is in Heating Tank.
The Desiccant pumps to the Solar Collector with the help of pump placed between the Heating
Tank and the Solar Collector.
The outlet of the Solar Collector is connected to the heating tank.
The hot desiccant is supplied to the Regenerator through the pump placed between the Inlet of
the Regenerator and the Heating Tank.
The outlet of the Regenerator is in the Cooling tank.
The cooling tank is used to supply the cold desiccant to the Absorber through the pump placed
between the Cooling Tank and the Absorber.
4.3 Steps of Performing Experiment:
1. Interconnect the components as shown in Figure 4.1.1.
2. Wait for steady state condition.
3. Measure the inlet and outlet temperature of desiccant and air, inlet and outlet humidity
and inlet and outlet concentrations.
4. Take 100ml of the desiccant and calculate its density.
5. The concentration is calculated using the correlation developed [Manuel R. C., 2009].
6. Take those readings for both absorber and regenerator.
7. Calculate the moisture removal rate.
Fig. 4.2.14 Demister Pad (Top and Front View)

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8. Calculate the moisture absorption rate.
9. Study the moisture removal rate and moisture absorption rate with the effect of different
variables namely air inlet temperature, desiccant inlet temperature and mass flow rate.

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Chapter-5
5. Results and Discussions:
We experimentally analyze in our project-
1. Effect of Regeneration Temperature (Hot Tank) on Temperature increase of outlet air.
2. Effect of Regeneration Temperature (Hot Tank) on Humidity Reduction (regenerator).
3. Effect of Regeneration Temperature (Hot Tank) on Humidity Decrease in the Absorber.
Ambient Conditions:
Lab Temperature-37˚C Relative Humidity-51%
Concentration Ratio:
For Regenerator: - H2O:CaCl2 ::100:1
For Absorber: - H2O:CaCl2 ::100:1
For observations for the effect of the regeneration temperature on the humidity
reduction in absorber and regenerator, we maintain the mass flow rate of the desiccant is
constant and the speed of the fan is kept constant.
Table No. 5.1 Observation Table
Hot Tank Cold Tank Absorber Absorber Regenerator Regenerator Time
Temperature
(˚C)
Temperature
(˚C)
RH %
Temperature
of outlet
air(˚C)
RH %
Temperature
of outlet air
(˚C)
48 20 43 35 55 38 12:25pm
45 23 44 36 50 37.5 12:30pm
40 25 44.5 36.6 48 37.3 12:35pm
39 26 45 37 44 36.7 12:40pm
38 32 46 37.5 41 36.5 12:45pm

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5.1 Effect of Regeneration Temperature (Hot Tank) on Temperature
increase of outlet air.
Fig. 5.1.1 Effect of Regeneration Temperature (Hot Tank) on Temperature Increase of Outlet Air
As seen in Fig. 5.1.1, we found that as the hot tank temperature decreases, temperature
of the outlet air of the absorber increases and the temperature of the outlet air of the
regenerator decreases. Resulting, high temperature of hot tank gives the lower temperature
for absorber thus the dehumidification increases by increasing the temperature of hot tank.
5.2 Effect of Regeneration Temperature (Hot Tank) on Humidity
Reduction.
As seen in Fig. 5.1.2, we found that the humidity of the outlet air from the absorber
increases with reduction in the temperature of the hot tank, whereas in the regenerator,
humidity of the outlet air from the regenerator decreases with the reduction in the
temperature of the hot tank.
So for good dehumidification we need a static high temperature of the hot tank for their
operation time and it’s about 60 to 70˚C. As high temperature of the regeneration (hot
tank), as good humidity reduction in absorber and regeneration of the desiccant solution.
33
34
35
36
37
38
39
36 37 38 39 40 41 42 43 44 45 46 47 48
AirOutletTemperature˚C
Regenerator Temperature (Hota Tank) ˚C
Absorber Regenerator

31. 31 | P a g e
Fig. 5.2.1 Effect of Regeneration Temperature (Hot Tank) on
Humidity Reduction in Absorber and Regenerator.
0
10
20
30
40
50
60
36 37 38 39 40 41 42 43 44 45 46 47 48
RelativeHumidity%
Regenerator Temperature (Hot Tank) ˚C
Absorber Regenerator

32. 32 | P a g e
Chapter-6
6. Conclusions:
The experimental work has been carried out and results have been discussed in above
section. And it is seen from the above discussions, the moisture removal rate increases with
the regeneration of desiccant. The moisture removal decreases when the inlet temperature of
desiccant in absorber increases. The maximum temperature for the regeneration is obtained for
black chrome coating in solar plate. These results are compared with the existing standard
results and found that they are approximately same. The water condensation rate doesn’t
change much with the air inlet temperature and desiccant temperature. It almost remains
constant. The water condensation rate increases with increasing desiccant inlet concentration.
The use of solar energy reduces the cost of operation of the system. The demand of the
energy is increasing day by day and it is more sense to use solar driven systems which are very
economical as compared to the conventionally electrically driven systems. In solar driven
dehumidifier we use solar energy for the regeneration of the desiccant instead of electrical
energy and Calcium Chloride is used as desiccant. Resulting, this system can be used as Air
Conditioning systems and it is not expensive.

33. 33 | P a g e
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