This document summarizes a research project that developed a low-cost evaporative cooler unit suitable for industrial environments in Sri Lanka. The unit uses both direct evaporative cooling and solid desiccant dehumidification to control temperature and humidity. Testing showed the unit was able to provide sufficient thermal comfort while only slightly changing relative humidity. Some design improvements were identified, such as using a larger evaporation chamber and improving airflow separation, but overall the evaporative cooling technology proved applicable to Sri Lanka's climate.
An Experimental Evaluation of Energy Saving in a Split-type Air Conditioner w...drboon
This research aims to experimentally evaluate the energy saving in a split-type air conditioner, which is using various types of evaporative cooling systems. The condensing unit is retrofitted with a cellulose corrugated pad, water sprayers, a water source and a pump. The power consumption and refrigeration capacity obtained from various cooling types are monitored and compared. The results show that the electrical consumption and coefficient of performance (COPR) significantly depend on the ambient conditions. Due to effects of condensing pressure, when the ambient temperature rises, the electrical consumption becomes higher, while the COPR becomes lower. Utilizing the indirect evaporative cooling system decreases the temperature of air entering the condensing unit, and this causes the system performance to be enhanced considerably. Among the investigated cases, the maximum energy saving occurs when the water spray cooperates with cellulose cooling pad. By using the evaporative cooling systems, COPR is improved by around 6-48%, and electrical consumption is approximately reduced by 4-15%.
An Experimental Evaluation of Energy Saving in a Split-type Air Conditioner w...drboon
This research aims to experimentally evaluate the energy saving in a split-type air conditioner, which is using various types of evaporative cooling systems. The condensing unit is retrofitted with a cellulose corrugated pad, water sprayers, a water source and a pump. The power consumption and refrigeration capacity obtained from various cooling types are monitored and compared. The results show that the electrical consumption and coefficient of performance (COPR) significantly depend on the ambient conditions. Due to effects of condensing pressure, when the ambient temperature rises, the electrical consumption becomes higher, while the COPR becomes lower. Utilizing the indirect evaporative cooling system decreases the temperature of air entering the condensing unit, and this causes the system performance to be enhanced considerably. Among the investigated cases, the maximum energy saving occurs when the water spray cooperates with cellulose cooling pad. By using the evaporative cooling systems, COPR is improved by around 6-48%, and electrical consumption is approximately reduced by 4-15%.
EXPERIMENTAL INVESTIGATION OF THERMAL PERFORMANCE OF CURTAIN-WALL-INTEGRATED ...ijiert bestjournal
A wall-integrated solar heating system refers to an archite ctural design approach that combines hot water generation with the building's construction sys tem. This combination allows this system to feature a hot water generation function and b ecome part of the building fa�ade. Environmental control devices and/or designs in buildings that are capable of harvesting solar thermal energy can effectively capture and st ore this solar energy and provide energy through the use of,for instance,a hot water system or a low-power thermoelectric material. Thermal energy storage (TES) is the key component f or such solar energy use,and it is one of the most promising and sustainable methods for energy stora ge in buildings. The TES systems used in buildings can be easily divided into three type s:sensible,latent,and thermo chemical energy storage (TCES).Because of its numerous advantages,such as its wide range of storage temperatures,high thermal capacity,non toxic ity,low cost,and easy obtain ability,water is often used as the storage medium in a sol ar water heating (SWH) system for domestic solar utilization.
Performance of water and diluted ethylene glycol as coolants for electronic c...IJERA Editor
As the number of transistors increases with new generation of microprocessor chips, the power draw and heat load to dissipate during operation increases. As a result of increasing the heat loads and heat fluxes the Conventional cooling technologies such as fan, heat sinks are unable to absorb and heat transfer excess heat dissipated by these new microprocessor. So, new technologies are needed to improve the heat removal capacity. In the present work single phase liquid cooling system with mini channel is analyzed and experimentally investigated. Mini channels are chosen as to provide higher heat transfer co-efficient than conventional channel. Copper pipes of 0.36 mm diameter are taken to fabricate heat sink and heat exchanger. A pump is used to circulate the fluid through heat sink and heat exchanger. A solid heated aluminium block to simulate heat generated electronic component is used and electrical input is supplied to the heated aluminium block and cooling system is placed over the heated block. The performance of the cooling system is analyzed from the experimental data obtained. It is experimentally observed that the mini channel liquid cooling system with water as a coolant has better performance than diluted ethylene glycol as coolant at different flow rates. The surface temperature of the heated aluminium block with convective heat transfer co-efficient is observed
Buildings contribute over 40 % of the total global primary energy use corresponding to 24 % of
the CO2 emissions of the world (IEA 2008). Building heating, ventilation, and air-conditioning
(HVAC) systems are responsible for about half of the energy use in buildings.
CFD Base Performance Evaluation of Earth-Air Tube Heat Exchanger for Natural ...journal ijrtem
ABSTRACT: The earths inside temperature is commonly higher than the outside air temperature in winter and lower in summer so it can makes the use of the earth convenient as warm source or cold sink respectively. Earth air heat exchanger can contributes to reduce in energy consumption. Numbers of research have been carried out on Computational Fluid Dynamics analysis of EATHE systems and still it requires optimum redevelopment. In the present work a 3D CAD model was developed for CFD analysis of earth air tube heat exchanger (EATHE) system. The obtained simulated results were compared with experimental results obtained from experimental setup installed at Bhopal situated in Central India. The temperature of earth at a certain depth about 2 m to 3 m of ground remains nearly constant throughout the year this constant temperature is called the undisturbed temperature of earth. The performance evolution was carried out to check the effect of pipe length, air flow velocity, depth of buried pipe and pipe diameter of EATHE system for summer cooling. The result shows that this system is more convenient only for summer cooling and not suitable for winter heating. KEYWORDS: CAD Modeling, Earth‐Air Tube Heat Exchanger, CFD Analysis, etc
Comparative Analysis of Forced Draft Cooling Tower Using Two Design Methods A...YogeshIJTSRD
Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere which results in cooling of the remainder water. The current research reviews various studies conducted on cooling tower using experimental and numerical techniques. Different design configuration and operating conditions on cooling towers are evaluated by various researchers. Significant findings from researches have shown new and improved design of cooling tower with much better performance as compared to conventional design. Neetish Kumar Sao | Dr. Surendra K. Dwivedi "Comparative Analysis of Forced Draft Cooling Tower Using Two Design Methods: A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd45100.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/45100/comparative-analysis-of-forced-draft-cooling-tower-using-two-design-methods-a-review/neetish-kumar-sao
Influence of Different Parameters on Heat Pipe PerformanceIJERA Editor
In electrical and electronic industry due to miniaturization of electronic components heat density increases
which, in turns increases the heat flux inside it. Scientist and many researchers are doing lot of work in this field
for thermal management of devices. Heat pipe is a device that is used in electronic circuit (micro and power
electronics), spacecraft & electrical components for cooling purpose. It is based on the principle of evaporation
and condensation of working fluid. Heat pipe made up of three main parts are evaporator, adiabatic and
condenser sections. In this working fluid vaporise at evaporator and transfers heat to condenser by adiabatic
section where heat release to surrounding. Vapour flows possible from evaporator to condenser section due to
vapour pressure difference exist between them. Use of heat pipe material, type of working fluid & its property,
wick structure, orientation, filled ratio, operating condition, dimensions of pipe has a prominent effect on heat
pipe performance. Variation of these parameters for minimum thermal resistance gives better performance.
Water cooled minichannel heat sinks for microprocessor cooling: Effect of fin...Danial Sohail
Heat sink with different fin spacing mounted on a microprocessor were tested for their heat removing capabilities by varying coolant flow rates over them
The effect of Al2O3 nanoparticles on the performance of heat pump to improve its
operational efficiency was presented in this theoretical and experimental study. In the
experimental work the heat pump charged with R600a inclusive with 0.06 % vol. of
Al2O3 and used as a nanorefrigerant. Three different nanoparticles size 20nm, 40 nm
and 50 nm of Al2O3 have been used for the preparation of nanolubricant in the present
study. The theoretical approach includes simulations modeling the heat pump
components such as compressor, evaporator, condenser and an expansion valve by
computer of the heat pump system by using commercial MATLAB. The results showed
that the addition of nanoparticles to the refrigerant will improve its characteristics of
refrigeration system heat transfer and thermal properties. Also, it showed that the
using nanorefrigerant in refrigeration system will work normally at all conditions
employed in this work. The experimental results found that the heat pump coefficient
of performance increased by 19.1%, but the power consumption reduced by 21.8 %
when using a mineral oil with 20 nm nanoparticles size of Al2O3 instead of the
conventional mineral oil only. Finally, the refrigeration effect increased and work of
compressor decreased by using a small nanoparticles size of Al2O3
EXPERIMENTAL INVESTIGATION OF THERMAL PERFORMANCE OF CURTAIN-WALL-INTEGRATED ...ijiert bestjournal
A wall-integrated solar heating system refers to an archite ctural design approach that combines hot water generation with the building's construction sys tem. This combination allows this system to feature a hot water generation function and b ecome part of the building fa�ade. Environmental control devices and/or designs in buildings that are capable of harvesting solar thermal energy can effectively capture and st ore this solar energy and provide energy through the use of,for instance,a hot water system or a low-power thermoelectric material. Thermal energy storage (TES) is the key component f or such solar energy use,and it is one of the most promising and sustainable methods for energy stora ge in buildings. The TES systems used in buildings can be easily divided into three type s:sensible,latent,and thermo chemical energy storage (TCES).Because of its numerous advantages,such as its wide range of storage temperatures,high thermal capacity,non toxic ity,low cost,and easy obtain ability,water is often used as the storage medium in a sol ar water heating (SWH) system for domestic solar utilization.
Performance of water and diluted ethylene glycol as coolants for electronic c...IJERA Editor
As the number of transistors increases with new generation of microprocessor chips, the power draw and heat load to dissipate during operation increases. As a result of increasing the heat loads and heat fluxes the Conventional cooling technologies such as fan, heat sinks are unable to absorb and heat transfer excess heat dissipated by these new microprocessor. So, new technologies are needed to improve the heat removal capacity. In the present work single phase liquid cooling system with mini channel is analyzed and experimentally investigated. Mini channels are chosen as to provide higher heat transfer co-efficient than conventional channel. Copper pipes of 0.36 mm diameter are taken to fabricate heat sink and heat exchanger. A pump is used to circulate the fluid through heat sink and heat exchanger. A solid heated aluminium block to simulate heat generated electronic component is used and electrical input is supplied to the heated aluminium block and cooling system is placed over the heated block. The performance of the cooling system is analyzed from the experimental data obtained. It is experimentally observed that the mini channel liquid cooling system with water as a coolant has better performance than diluted ethylene glycol as coolant at different flow rates. The surface temperature of the heated aluminium block with convective heat transfer co-efficient is observed
Buildings contribute over 40 % of the total global primary energy use corresponding to 24 % of
the CO2 emissions of the world (IEA 2008). Building heating, ventilation, and air-conditioning
(HVAC) systems are responsible for about half of the energy use in buildings.
CFD Base Performance Evaluation of Earth-Air Tube Heat Exchanger for Natural ...journal ijrtem
ABSTRACT: The earths inside temperature is commonly higher than the outside air temperature in winter and lower in summer so it can makes the use of the earth convenient as warm source or cold sink respectively. Earth air heat exchanger can contributes to reduce in energy consumption. Numbers of research have been carried out on Computational Fluid Dynamics analysis of EATHE systems and still it requires optimum redevelopment. In the present work a 3D CAD model was developed for CFD analysis of earth air tube heat exchanger (EATHE) system. The obtained simulated results were compared with experimental results obtained from experimental setup installed at Bhopal situated in Central India. The temperature of earth at a certain depth about 2 m to 3 m of ground remains nearly constant throughout the year this constant temperature is called the undisturbed temperature of earth. The performance evolution was carried out to check the effect of pipe length, air flow velocity, depth of buried pipe and pipe diameter of EATHE system for summer cooling. The result shows that this system is more convenient only for summer cooling and not suitable for winter heating. KEYWORDS: CAD Modeling, Earth‐Air Tube Heat Exchanger, CFD Analysis, etc
Comparative Analysis of Forced Draft Cooling Tower Using Two Design Methods A...YogeshIJTSRD
Cooling towers make use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere which results in cooling of the remainder water. The current research reviews various studies conducted on cooling tower using experimental and numerical techniques. Different design configuration and operating conditions on cooling towers are evaluated by various researchers. Significant findings from researches have shown new and improved design of cooling tower with much better performance as compared to conventional design. Neetish Kumar Sao | Dr. Surendra K. Dwivedi "Comparative Analysis of Forced Draft Cooling Tower Using Two Design Methods: A Review" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-5 , August 2021, URL: https://www.ijtsrd.com/papers/ijtsrd45100.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/45100/comparative-analysis-of-forced-draft-cooling-tower-using-two-design-methods-a-review/neetish-kumar-sao
Influence of Different Parameters on Heat Pipe PerformanceIJERA Editor
In electrical and electronic industry due to miniaturization of electronic components heat density increases
which, in turns increases the heat flux inside it. Scientist and many researchers are doing lot of work in this field
for thermal management of devices. Heat pipe is a device that is used in electronic circuit (micro and power
electronics), spacecraft & electrical components for cooling purpose. It is based on the principle of evaporation
and condensation of working fluid. Heat pipe made up of three main parts are evaporator, adiabatic and
condenser sections. In this working fluid vaporise at evaporator and transfers heat to condenser by adiabatic
section where heat release to surrounding. Vapour flows possible from evaporator to condenser section due to
vapour pressure difference exist between them. Use of heat pipe material, type of working fluid & its property,
wick structure, orientation, filled ratio, operating condition, dimensions of pipe has a prominent effect on heat
pipe performance. Variation of these parameters for minimum thermal resistance gives better performance.
Water cooled minichannel heat sinks for microprocessor cooling: Effect of fin...Danial Sohail
Heat sink with different fin spacing mounted on a microprocessor were tested for their heat removing capabilities by varying coolant flow rates over them
The effect of Al2O3 nanoparticles on the performance of heat pump to improve its
operational efficiency was presented in this theoretical and experimental study. In the
experimental work the heat pump charged with R600a inclusive with 0.06 % vol. of
Al2O3 and used as a nanorefrigerant. Three different nanoparticles size 20nm, 40 nm
and 50 nm of Al2O3 have been used for the preparation of nanolubricant in the present
study. The theoretical approach includes simulations modeling the heat pump
components such as compressor, evaporator, condenser and an expansion valve by
computer of the heat pump system by using commercial MATLAB. The results showed
that the addition of nanoparticles to the refrigerant will improve its characteristics of
refrigeration system heat transfer and thermal properties. Also, it showed that the
using nanorefrigerant in refrigeration system will work normally at all conditions
employed in this work. The experimental results found that the heat pump coefficient
of performance increased by 19.1%, but the power consumption reduced by 21.8 %
when using a mineral oil with 20 nm nanoparticles size of Al2O3 instead of the
conventional mineral oil only. Finally, the refrigeration effect increased and work of
compressor decreased by using a small nanoparticles size of Al2O3
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
CFD Simulation of Air Conditioning System of the Classroomijtsrd
We have focused on the design and modifications of air cooling duct system using Computational Fluid Dynamics CFD considering all air flow patterns affecting the system efficiency. Necessary tools and methods are applied for efficient designing. The different load conditions and the layout of the duct system need to be very accurate because if any deviation will result to problems like uneven cooling, frictional losses, increased noise and vibrations and also more power consumption. The above problems highlight the importance for optimizing the duct design to obtain desired flow conditions. Our work involves use of theoretical and software tools to get a detailed comparative analysis of the costs and benefits involved in selecting a particular shape rectangular or circular for the duct according to the working conditions. The focus of this paper rests on using psychrometry chart to calculate the cooling load and other parameters. Gaurav Srivastava | Aman Kumar | Dipti Chandel | Harsh Dabas | Ashish Mishra | Saurabh ""CFD Simulation of Air Conditioning System of the Classroom"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23824.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23824/cfd-simulation-of-air-conditioning-system-of-the-classroom/gaurav-srivastava
Design of waste heat driven vapour adsorption cooling system for vehicle air ...eSAT Journals
Abstract In this present era more & more focus is to be given on energy conservation. Refrigeration & air conditioning is one of the growing field of engineering, the existing system are hampering the environment as they are suffering from various environmental problems such as depletion of ozone layer & global warming due to emission of harmful gases such as HFC’s ,CFC’s & CO2 as they were using traditional refrigerants. Waste heat driven Vapour adsorption cooling system is eco-friendly, efficient, & reliable in nature. But on the other hand this system having lowers COP as compare to existing systems which is Due to the lack of research and advancement in the system. By considering the environmental aspects & need of energy conservation it is necessary to design and developed the VAR’s system which will successfully compete the existing systems. This paper will give the idea about the Design of waste heat driven vapour adsorption system of 2KW capacity for vehicle air-conditioning & refrigeration application. The adsorber bed is the heart of the cooling system and it can affect the performance of the system to the greater extent. So that while designing the VAR cooling system more focused is given on design and selection of adsorber bed. This article mainly focused on the various and important design parameters of the vapour adsorption cooling system Such as Adsorber bed design, adsorber and adsorbate mass, design of evaporator & condenser, Coefficient of performance(COP), Specific cooling power (SCP) and the other performance affecting parameters. Keywords: Vapour Adsorption, Design Parameters, Low Grade Thermal Energy, Adsorbate & Adsorbent.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Fabrication, Designing & Performance Analysis of Solar Parabolic TroughIJERA Editor
A parabolic trough solar collector uses a parabolic cylinder to reflect and concentrate sun radiations towards a receiver tube located at the focus line of the parabolic cylinder. The receiver absorbs the incoming radiations and transforms them into thermal energy, the latter being transported and collected by a fluid medium circulating within the receiver tube.This method of concentrated solar collection has the advantage of high efficiency and low cost, and can be used either for thermal energy collection, for generating electricity or for both, This paper focused on the fabrication and designing of solar parabolic trough, The designing of trough is depend upon the following parameters : Aperture of the concentrator , Inner diameter of absorber tube, Outer diameter of absorber tube, Inner diameter of glass tube, Outer diameter of glass tube, Length of parabolic trough, Concentration ratio, Collector aperture area, Specular reflectivity of concentrator, Glass cover transitivity for solar radiation, Absorber tube emissivity/emissivity, Intercept factor, Emissivity of absorber tube surface and Emissivity of glass. The performance analysis will be based on the Experimental data collection and calculations with reference to: Thermal performance calculations, Overall loss coefficient and heat correlations. Heat transfer coefficient on the inside surface of the absorber tube and Heat transfer coefficient between the absorber tube and the Cover.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Recent advances in semiconductor technology show the improvement of fabrication on
electronics appliances in terms of performance, power density and even the size. This great achievement
however led to some major problems on thermal and heat distribution of the electronic devices. This
thermal problem could reduce the efficiency and reliability of the electronic devices. In order to minimize
this thermal problem, an optimal cooling techniques need to be applied during the operation. There are
various cooling techniques have been used and one of them is passive pin fin heat sink approach. This
paper focuses on inline pin fin heat sink, which use copper material with different shapes of pin fin and a
constant 5.5W heat sources. The simulation model has been formulated using COMSOL Multiphysics
software to stimulate the pin fin design, study the thermal distribution and the maximum heat profile.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
International Journal of Computational Engineering Research(IJCER)
Extended_Abstract
1. 15TH
ERU SYMPOSIUM, 2009: FACULTY OF ENGINEERING, UNIVERSITY OF MORATUWA
1
DEVELOPMENT OF LOW COST EVAPORATIVE COOLER UNIT TO SUIT
INDUSTRIAL ENVIRONMENT
Project Advisor: Prof. R.A. Attalage
G.P.T.K. Abeysekara, K.H.H.G. Ketanwila, K.A.P. Vithana
E-mail: thanujakasun@gmail.com,ketanwila@gmail.com,koswatta@gmail.com
Department of Mechanical Engineering, University of Moratuwa, Moratuwa, Sri Lanka
Abstract
The purpose of this paper is to demonstrate the adaptability of evaporative cooling technology to Sri Lankan
environment. Desiccant cooling technology is initiated to control the relative humidity level of the environment. A
generic model of the evaporative cooler is constructed using direct evaporative cooling method and solid desiccant
dehumidification method. The model was installed in the testing environment. The results show that the evaporative
cooler is provided the sufficient level of thermal comfort to the people changing relative humidity slightly.
1. Introduction
This paper based on the research and development project
conducted by the undergraduates as requirement of fulfilling
the degree to develop a cooler unit to suit industrial
environment. Evaporative cooling is ancient and common
technique within the middle-east countries. This paper
discusses the applicability of evaporative cooling technique
to the hot humid environment in Sri Lanka.
On behalf of the industrial engineering context, human
thermal comfort is key parameter of the efficiency and
ergonomic aspects of man power. To maintain the optimum
efficiency and industrial standards, maintaining a thermal
comfort is essential requirement.
Because of high relative humidity level in Sri Lanka,
direct evaporative cooling can’t be used to reach required
thermal comfort level. Solid dehumidification with heat
exchanger was added to the design to overcome the
problem. This paper analyses the results of the new method
and attempts to provide acceptable, cost-effective solution.
Dealing with small air capacities for evaporative cooling
was difficult than large air volume. So another goal of this
project is to check the adaptability to the industrial
environment. Almost all industries produce waste heat, this
project targets to utilize that heat as a source.
2. Methodology
Analysis for temperature and relative humidity readings of
Sri Lanka was done and project objective were clearly
identified. Existing evaporative cooling and desiccant
cooling technologies were studied. Optimum design
methodology was selected and cooler was fabricated to
install in controlled environment. After the test runs of the
machine, environmental data were collected and checked
for the adaptability of concept.
2.1 Construction
Design is constructed by two major parts. Primary air
preparation unit and evaporative chamber are those two key
elements of the design. Atmospheric air is taken as the
primary air. Dehumidification of primary air is done by
Silica gel in the desiccant wheel and water evaporation is
done by electronically controlled nozzles.
In the desiccant wheel construction, flat iron was used to
make the frame. No. 6 steel mesh is used to trap the Silica
Gel in the wheel. Nuts and bolts were used to fix the
desiccant particles to mesh. Wheel was rotated by a flat belt
in the outer perimeter so that it causes minimum disturbance
to the air flow. Special concern is taken to desiccant
packing system to reduce pressure drop as well as to archive
maximum efficiency of the wheel.
10mm Carbon steel mesh was used to fabricate the heat
exchanging body of heat recovery wheel with the guidance
of circular shaped flat iron frame supported by traverse iron
bars. By increasing the number of layers, the total heat
capacity of the wheel can be improved to meet the design
requirements.
Flow separation duct was constructed by 0.8mm a thick
plate which is developed from semi circular shape to cross
section with 2400
degree. 1200
duct resolute into a circular
duct and also 1800
side. This duct was made with high
precision to minimize flow mixing. For that plasma cutting
technique was used. Insulation is used to reduce conduction
heat exchange at the solid boundary.
Outer frame was constructed by L iron bars and using
6204 bearing and shaft, wheels and duct is fixed to frame.
Various reinforcements were used to get the stability of the
frame.
One motor is used drive both desiccant wheel and energy
recovery wheel. Two pulleys made out of wood are
emotionally involved to the motor using a long shaft and
this shaft is supported in several locations.
Main blower and secondary was attached to the main
frame using angle iron bars. It was constructed three ducts
also to perform following tasks.
Supply air to the room
Return air for the energy recovery wheel
Air preheated to desiccant regeneration
Evaporation chamber consists of three nozzles with
different angles for testing purposes (one nozzle is enough
for the evaporation). Pump is used for pressurize the water
2. 15TH
ERU SYMPOSIUM, 2008: FACULTY OF ENGINEERING, UNIVERSITY OF MORATUWA
2
supply to the room. Atomization pressure of the nozzle is
7bar.
Regeneration heat for silica is given by a Nichrome coil,
the coil is attached using ceramic insulations.
Insulation was placed where it is needed.
2.2 Process Diagram
Diagram for the complete process can be shown as below
figure. Atmospheric air is heated to provide hot air and cold
air is taken from the controlled environment.
2.3 Testing Methodology
Developed system was installed to controlled area and
testing run was carried out. By changing the evaporation
rate of the nozzles, changing the nozzle angels, changing the
temperature of the desiccant regeneration side, and on
different environmental conditions, tests were carried out
and results were recorded.
3. Results and Discussions
3.1 Results
Test conditioned are 7bar nozzle pressure and counter flow
nozzle angle.
Dry bulb
temperature
Relative
Humidity
Air velocity
Initial
reading
300
C 70% 1.3ms-1
After 15
minutes
28.60
C 79% 1.3ms-1
After 30
minutes
27.90
C 86% 1.3ms-1
Test conditioned are 7bar nozzle pressure and cross flow
nozzle angle.
Dry bulb
temperature
Relative
Humidity
Air velocity
Initial
reading
30.10
C 70% 1.3ms-1
After 15
minutes
28.30
C 83% 1.3ms-1
After 30
minutes
27.60
C 92% 1.3ms-1
Test conditioned are 5bar nozzle pressure and cross flow
nozzle angle.
Dry bulb
temperature
Relative
Humidity
Air velocity
Initial
reading
30.30
C 67% 1..3ms-1
After 15
minutes
28.20
C 85% 1.3ms-1
After 30
minutes
27.20
C 98% 1.3ms-1
Model test results show that the environmental condition
is reached to the margin of thermal comfort region after
installing evaporative cooler. With the advanced velocity of
the room gives additional comfort. This velocity mainly
suits industrial environment.
3.2 Discussion
Best suited conditioned are 7 bar and counter flow nozzle
angel.
After the testing period, it is apparent that the technology
is applicable to Sri Lankan environment. Most probably
suits industrial environment. Desiccant cooling technology
is the success factor of the design. By effectively controlling
the nozzles, the efficiency of the system will be improved.
Desiccant wheel has relatively high bypass factor than
commercially existing desiccant wheels. By using
physically bonded desiccant method would increase
efficiency of the wheel.
Coated aluminum mesh would be best suited for the
energy recovery wheel that will increase heat capacity and
also heat conduction rate.
Flow separation methods also can improve design
changes like overlap the ducts using a third duct to connect
other two.
Air volume of evaporation chamber is not enough in this
design, with a large evaporation chamber will be best suited
for the design.
Little amount of water vapor tends to come with the air
flow. Attaching baffle plates in the evaporation chamber
will reduce mist. With a proper air distribution duct system
will be an added advantage.
Main difficulty of this project is to manufacture desiccant
wheel. To hold the desiccant into a mesh and make it
turning is the most difficult part and most time consuming
part.
References
Watt, J. R. (1986). Evaporative Air Conditinoning
Handbook. London: Chapman & Hall.
Standard 55, BSR/ASHRAE. (2003, February). Thermal
Environmental Conditions for Human Occupancy. Atlanta.
ASHRAE. (2004). ASHRAE handbook of HVAC systems
and equipments. Atlanta.
Ryan, S. S. (2000, December). Desiccant Dehumidification
Wheel Test Guide. Cole Boulevard, Colorado, United
States.
Scheuchi, R. (2009, March 10). Hoval Rotary Heat
Exchanger for Heat Recovery in Ventilation Systems.
United States.
