This document summarizes an experimental study that investigated the adsorption capacity of various activated carbon/refrigerant pairs. Specifically, it tested activated carbon powder and granules paired with R-134a, R-407c, and R-507A refrigerants. A finned-tube heat exchanger was used to minimize heat and mass transfer limitations. The maximum adsorption capacities were measured at different temperatures. The highest capacity of 0.8352 kg/kg was found for activated carbon powder paired with R-134a at 25°C, while the lowest capacity of 0.3207 kg/kg was for the same pair at 50°C. Therefore, activated carbon powder with R-134a was determined to
An Investigative and Concise Review on Evaporation and Condensation Processes...IJERA Editor
The vapour adsorption refrigeration is based on the evaporation and condensation of a refrigerant combined with adsorption or chemical reaction. The towering fossil fuel price and the responsiveness of environmental problems offer many potential applications to thermal powered adsorption cooling. However, the adsorption cooling machines still have some disadvantages that hinder their wide application. The patents surveyed are classified into four main groups: adsorption system development, adsorbent bed innovation, adsorbent/adsorbate material development and novel application of adsorption cooling system. The adsorption refrigeration is based on the evaporation and condensation of a refrigerant combined with adsorption or chemical reaction. Important targets are to reach a high efficiency through optimization measures at various components and the control system. On the other hand measures are to verify to simplify the construction with regard to a low-cost manufacturing, as well as to reach long periods with maintenance-free operation. This review paper gives a comprehensive review on the work carried out on vapour adsorption refrigeration for cryogenic applications.
The document summarizes an experimental investigation on the performance of an air conditioner using R32 refrigerant. It begins with an abstract describing the refrigerant comparison experiment conducted on a 1.5 ton capacity air conditioning system using R22, R134a, and R32. Performance parameters like coefficient of performance, mass flow rate, and power to the compressor were calculated. The results and simulations showed R32 to be the most efficient refrigerant for retrofitting air conditioning systems due to its lower global warming potential and atmospheric lifetime compared to R22.
Experimental investigation of cooling performance of an Automobile radiator u...IJERD Editor
This document summarizes an experimental study that investigated the cooling performance of an automobile radiator using an Al2O3-water+ethylene glycol nanofluid. Different volume fractions of Al2O3 nanoparticles between 0.01-0.08% were added to the base fluid and tested. The maximum heat transfer performance observed was a 48% increase over water for the 0.08% volume fraction nanofluid. Flow rates were also varied between 3-15 liters per minute, showing increased heat transfer with higher flow. The nanofluid had increased thermal conductivity compared to the base fluid, improving the radiator's cooling capacity.
Modeling and Fluid Flow Analysis of Wavy Fin Based Automotive RadiatorIJERA Editor
In continuous technological development, an automotive industry has increased the demand for high efficiency engines. A high efficiency engines in not only based on its performance but also for better fuel economy and less emission rate. Radiator is one of the important parts of the internal combustion engine cooling system. The manufacturing cost of the radiator is 20 percent of the whole cost of the engine. So improving the performance and reducing cost of radiators are necessary research. For higher cooling capacity of radiator, addition of fins is one of the approaches to increase the cooling rate of the radiator. In addition, heat transfer fluids at air and fluid side such as water and ethylene glycol exhibit very low thermal conductivity. As a result there is a need for new and innovative heat transfer fluids, known as “Nano fluid” for improving heat transfer rate in an automotive radiator. Recently there have been considerable research findings highlighting superior heat transfer performances of nanofluids about 15-25% of heat transfer enhancement can be achieved by using types of nanofluids. With these specific characteristics, the size and weight of an automotive car radiator can be reduced without affecting its heat transfer performance. An automotive radiator (Wavy fin type) model is modeled on modeling software CATIA V5 and performance evaluation is done on pre-processing software ANSYS 14.0. The temperature and velocity distribution of coolant and air are analyzed by using Computational fluid dynamics environment software CFX. Results have shown that the rate of heat transfer is better when nano fluid (Si C + water) is used as coolant, than the conventional coolant.
Experimental Evaluation of Refrigerant Mixtures as Substitutes for HFC134aIOSRJMCE
The document describes an experimental evaluation of refrigerant mixtures as substitutes for HFC134a in a 200 liter domestic refrigeration system. The study tested mixtures of propane (R290) and butane (R600a) at different mass ratios, including R600a/R290 at ratios of 70/30, 60/40, and 50/50 by weight percent. The results showed that the R600a/R290 mixture at a ratio of 60/40 performed better than the other mixtures and HFC134a in terms of refrigerating effect and coefficient of performance. Specifically, the 60/40 mixture achieved a refrigerating effect 10% higher than HFC134a at -5°C and 35.
The document summarizes a carburizing process called FC-35 that uses a mixture of LPG and CO2 gases to produce the furnace atmosphere. It claims to offer shorter process times, lower costs, and clean components compared to traditional endothermic gas processes. Test results showed uniform hardness profiles and carbon gradients across loaded components. The FC-35 process demonstrated good "throwing ability" for carburizing difficult geometries.
IRJET- Controlling A Multi-Evaporator Refrigeration System that Uses Cuo/R134...IRJET Journal
This document discusses controlling a refrigeration system with multiple evaporators using a CuO/R134a nanofluid as the refrigerant. It first experimentally investigates how the evaporator heat transfer coefficient is affected by heat flux, nanofluid mass flux, and nanoparticle concentration. The heat transfer coefficient increased with heat and mass fluxes and peaked at a 0.5% nanoparticle concentration. Two correlations were developed to relate heat transfer to these parameters. It then modifies the system to add a second evaporator and uses the experimental results to control heat and mass fluxes to control the heat transfer coefficient and evaporator behavior. This approach could allow controlling multiple evaporators with one compressor in future work.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
An Investigative and Concise Review on Evaporation and Condensation Processes...IJERA Editor
The vapour adsorption refrigeration is based on the evaporation and condensation of a refrigerant combined with adsorption or chemical reaction. The towering fossil fuel price and the responsiveness of environmental problems offer many potential applications to thermal powered adsorption cooling. However, the adsorption cooling machines still have some disadvantages that hinder their wide application. The patents surveyed are classified into four main groups: adsorption system development, adsorbent bed innovation, adsorbent/adsorbate material development and novel application of adsorption cooling system. The adsorption refrigeration is based on the evaporation and condensation of a refrigerant combined with adsorption or chemical reaction. Important targets are to reach a high efficiency through optimization measures at various components and the control system. On the other hand measures are to verify to simplify the construction with regard to a low-cost manufacturing, as well as to reach long periods with maintenance-free operation. This review paper gives a comprehensive review on the work carried out on vapour adsorption refrigeration for cryogenic applications.
The document summarizes an experimental investigation on the performance of an air conditioner using R32 refrigerant. It begins with an abstract describing the refrigerant comparison experiment conducted on a 1.5 ton capacity air conditioning system using R22, R134a, and R32. Performance parameters like coefficient of performance, mass flow rate, and power to the compressor were calculated. The results and simulations showed R32 to be the most efficient refrigerant for retrofitting air conditioning systems due to its lower global warming potential and atmospheric lifetime compared to R22.
Experimental investigation of cooling performance of an Automobile radiator u...IJERD Editor
This document summarizes an experimental study that investigated the cooling performance of an automobile radiator using an Al2O3-water+ethylene glycol nanofluid. Different volume fractions of Al2O3 nanoparticles between 0.01-0.08% were added to the base fluid and tested. The maximum heat transfer performance observed was a 48% increase over water for the 0.08% volume fraction nanofluid. Flow rates were also varied between 3-15 liters per minute, showing increased heat transfer with higher flow. The nanofluid had increased thermal conductivity compared to the base fluid, improving the radiator's cooling capacity.
Modeling and Fluid Flow Analysis of Wavy Fin Based Automotive RadiatorIJERA Editor
In continuous technological development, an automotive industry has increased the demand for high efficiency engines. A high efficiency engines in not only based on its performance but also for better fuel economy and less emission rate. Radiator is one of the important parts of the internal combustion engine cooling system. The manufacturing cost of the radiator is 20 percent of the whole cost of the engine. So improving the performance and reducing cost of radiators are necessary research. For higher cooling capacity of radiator, addition of fins is one of the approaches to increase the cooling rate of the radiator. In addition, heat transfer fluids at air and fluid side such as water and ethylene glycol exhibit very low thermal conductivity. As a result there is a need for new and innovative heat transfer fluids, known as “Nano fluid” for improving heat transfer rate in an automotive radiator. Recently there have been considerable research findings highlighting superior heat transfer performances of nanofluids about 15-25% of heat transfer enhancement can be achieved by using types of nanofluids. With these specific characteristics, the size and weight of an automotive car radiator can be reduced without affecting its heat transfer performance. An automotive radiator (Wavy fin type) model is modeled on modeling software CATIA V5 and performance evaluation is done on pre-processing software ANSYS 14.0. The temperature and velocity distribution of coolant and air are analyzed by using Computational fluid dynamics environment software CFX. Results have shown that the rate of heat transfer is better when nano fluid (Si C + water) is used as coolant, than the conventional coolant.
Experimental Evaluation of Refrigerant Mixtures as Substitutes for HFC134aIOSRJMCE
The document describes an experimental evaluation of refrigerant mixtures as substitutes for HFC134a in a 200 liter domestic refrigeration system. The study tested mixtures of propane (R290) and butane (R600a) at different mass ratios, including R600a/R290 at ratios of 70/30, 60/40, and 50/50 by weight percent. The results showed that the R600a/R290 mixture at a ratio of 60/40 performed better than the other mixtures and HFC134a in terms of refrigerating effect and coefficient of performance. Specifically, the 60/40 mixture achieved a refrigerating effect 10% higher than HFC134a at -5°C and 35.
The document summarizes a carburizing process called FC-35 that uses a mixture of LPG and CO2 gases to produce the furnace atmosphere. It claims to offer shorter process times, lower costs, and clean components compared to traditional endothermic gas processes. Test results showed uniform hardness profiles and carbon gradients across loaded components. The FC-35 process demonstrated good "throwing ability" for carburizing difficult geometries.
IRJET- Controlling A Multi-Evaporator Refrigeration System that Uses Cuo/R134...IRJET Journal
This document discusses controlling a refrigeration system with multiple evaporators using a CuO/R134a nanofluid as the refrigerant. It first experimentally investigates how the evaporator heat transfer coefficient is affected by heat flux, nanofluid mass flux, and nanoparticle concentration. The heat transfer coefficient increased with heat and mass fluxes and peaked at a 0.5% nanoparticle concentration. Two correlations were developed to relate heat transfer to these parameters. It then modifies the system to add a second evaporator and uses the experimental results to control heat and mass fluxes to control the heat transfer coefficient and evaporator behavior. This approach could allow controlling multiple evaporators with one compressor in future work.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
To study the application of nanorefrigerant in refrigeration system a revieweSAT Journals
1. The document reviews the application of nanorefrigerants in refrigeration systems. Nanorefrigerants are a combination of nanoparticles and refrigerants that can improve heat transfer properties compared to conventional refrigerants.
2. Several studies are summarized that found improvements like increased heat transfer, higher COP, and reduced energy consumption when using nanorefrigerants made of particles like Al2O3, CuO, and TiO2 mixed with refrigerants like R134a and R600a.
3. The review concludes that nanorefrigerants show promise for making refrigeration processes more efficient and reducing their environmental impact, though more study is still needed to optimize nanoparticle type and concentration.
This document presents a theoretical and experimental analysis of a direct-fired double effect lithium bromide/water absorption chiller located at a lighting technology company in Egypt. The chiller has a cooling capacity of 500 tons and uses a parallel flow configuration. Temperature measurements were taken at various points in the chiller components in July 2013 and July 2014. Mathematical equations were developed to model the chiller and estimate the coefficient of performance and heat transfer rates based on temperature and flow rate data. Theoretical and experimental analyses were conducted to evaluate how the COP is affected by factors like heat exchanger effectiveness and circulation ratio. The results show that the chiller's COP was lower in 2014 compared to 2013, possibly due to degradation of the heat ex
VOLUME-7 ISSUE-8, AUGUST 2019 , International Journal of Research in Advent Technology (IJRAT) , ISSN: 2321-9637 (Online) Published By: MG Aricent Pvt Ltd
This document describes an experimental study on enhancing heat transfer in a domestic refrigerator using a nanofluid as the working fluid. Specifically, it investigates using a mixture of R600a refrigerant, mineral oil, and alumina nanoparticles (Al2O3) in a vapor compression refrigeration system. The addition of nanoparticles is intended to improve the thermophysical properties and heat transfer characteristics of the working fluid mixture. Experimental results found that using the nanofluid working fluid reduced power consumption by 11.5% compared to using POE oil alone, and increased the freezing capacity of the refrigerator. Thus the study demonstrates the feasibility of using Al2O3 nanofluids to enhance the performance of refrigeration systems.
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.
Thermodynamic analysis of vapour compression refrigeration system using alte...IOSR Journals
This document discusses thermodynamic analysis of alternative refrigerants for vapor compression refrigeration systems. It aims to analyze the environmental and energy consumption impacts of various refrigerants. The document defines key terms like ozone depletion potential and global warming potential. It then analyzes several potential refrigerant alternatives to R22 and R134a like propane, isobutane, R410a, R407c, and a mixture called MO9. The thermodynamic properties of these refrigerants are obtained from software and their coefficients of performance are compared. The analysis found that MO9 shows potential as a suitable substitute for R134a in new and retrofit systems due to its performance and lower environmental impact.
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
PERFORMANCE ENHANCEMENT OF HOUSEHOLD REFRIGERATOR BY USING TiO2 NANO LUBRICAN...Niyas PP
The document describes experiments conducted to enhance the performance of a household refrigerator by adding TiO2 nanoparticles to the compressor oil. Three experiments were performed: 1) with PAG oil, 2) with SUNISO 3GS oil, and 3) with SUNISO 3GS oil mixed with 0.05% TiO2 nanoparticles. Results showed that actual COP increased by 21% with pure SUNISO 3GS oil and by 35% with the nano-lubricant oil mixture compared to PAG oil. Power consumption was also reduced by 17.25% with pure SUNISO 3GS oil and 25.83% with the nano-lubricant oil. The nano-lubricant improved heat transfer and reduced friction inside the
Experimental Study and CFD Analysis of Thermal Performance Improvement of Car...IRJET Journal
This document summarizes an experimental study and CFD analysis of using MgO/water nanofluid to improve the thermal performance of a car radiator. Experiments were conducted to test different volume fractions of MgO/water nanofluid and measure its thermal properties and heat transfer rate in the radiator. CFD simulations were also performed to validate the experimental temperature distributions. The results showed that using MgO/water nanofluid as the coolant led to higher heat transfer rates and outlet temperatures in the radiator compared to using just water, with enhancements of up to 70% observed, and the performance increased with higher nanoparticle volume fractions.
Experimental Study of Heat Transfer Enhancement in Triple Tube Heat Exchanger...IRJET Journal
The document describes an experimental study of heat transfer enhancement in a triple tube heat exchanger using CuO and Al2O3 nanofluids. A triple tube heat exchanger was tested with hot water flowing through the intermediate tube and cold water flowing through the inner and outer tubes. Nanofluids of CuO and Al2O3 with a 0.033% volumetric concentration were used. The heat transfer rate and effectiveness of the triple tube heat exchanger were evaluated experimentally for different flow rates of the hot fluid, with the cold fluid flow rate held constant. The results showed that use of nanofluids increased the heat transfer rate and effectiveness compared to using plain water as the working fluid.
The document describes the design of a batch stirred tank reactor for producing industrial alcohol through fermentation. Key details include:
- The reactor will be a jacketed, stirred tank reactor with a volume of 377m3, 10m height, 6.8m diameter, and carbon steel construction.
- It will operate at 32°C and 1.8 atm with a 52 hour batch time and use a torispherical head.
- Cooling will be provided by a 17m2 jacket using 33 tons/hr of cooling water from 20-28°C.
- Agitation will be from three 6-bladed impellers 2.2m in diameter running at 44 RPM and requiring 60
This document describes the design and fabrication of an LPG refrigeration system. It works by using the expansion of liquefied petroleum gas (LPG) to produce a cooling effect. As high pressure LPG passes through a capillary tube, the pressure drops and LPG vaporizes, absorbing heat from the surroundings. This vaporization process allows LPG to be used as a refrigerant. The document outlines the system's components, calculations of its refrigeration capacity and coefficient of performance, experimental testing procedures, and conclusions that LPG can achieve higher performance than traditional refrigerants like R134a.
I. Packed bed reactors are commonly used for catalytic reactions and consist of solid catalyst particles packed into tubes with fluids entering and leaving through headers. Heat is transferred between the reaction occurring within the catalyst particles and a cooling or heating fluid on the shell side.
II. Effective heat transfer requires a high ratio of heat transfer surface area to reactor volume. Boiling fluids are often used as they have high heat transfer coefficients and can maintain a constant temperature over the cooling jacket.
III. Heat transfer coefficients in packed beds are calculated based on temperature profiles and effective thermal conductivity, accounting for resistance near the tube wall and in the packed bed region. Coefficients depend on particle size, tube diameter, and fluid properties and flow
STUDY ON THE BEHAVIOUR OF CUO NANO PARTICLES IN RADIATOR HEAT EXCHANGER FOR A...P singh
In this present study, the forced convective heat transfer performance of automobile radiator has been studied experimentally by using Nano fluid (CuO-Water) as a coolant for an automobile radiator.. Experimental works were conducted to investigate the effect of Copper-Oxide (CuO) nanoparticles volume concentration and the operating temperatures on the rate of Nano fluids heat transfer in a radiator heat Exchanger. CuO nanoparticles were mixed with the base fluid water and also Sodium Lauryl Sulphate (SLS) powder was added to enhance the mixing process and stabilize the dispersion of the Nano fluids. Experimental runs were conducted at varying operating temperatures which include that, CuO-water at different temperature such as 40℃, 50℃, 60℃, 70℃, 75℃, 78℃, 80℃, 83℃. Among the operating temperatures selected for study 80℃, gives the best performance in heat transfer and the convection heat transfer coefficient. The results of the current work generally indicate that Nano fluids have the potential to enhance the heat transfer of a compact heat exchanger. Results indicate that, best overall heat transfer coefficient for the radiator is obtained at a hot fluid inlet temperature of 80℃, and at a flow rate of 0.075kg/sec.
This document presents a theoretical analysis of a vapor compression refrigeration system using refrigerants R-22, R407C, and R410A. Equations are developed based on the first and second laws of thermodynamics to model the system and analyze parameters such as coefficient of performance (COP), exergetic efficiency, and exergy destruction ratio (EDR). Results show R410A has the highest relative capacity change with increased subcooling degree and COP increase with higher evaporator temperatures. Exergetic efficiency is maximized and EDR minimized at evaporator temperatures of -30 to -35°C. R410A performance is better than R407C based on the thermodynamic analysis.
IRJET- Experimental Investigation of Pipe in Pipe Tube Heat Exchanger using S...IRJET Journal
This document presents an experimental investigation of a pipe-in-pipe tube heat exchanger using silica (SiO2) nanofluid. The heat exchanger consists of an outer steel pipe and inner aluminum pipe. SiO2 nanofluid with 2% volume concentration and 100nm nanoparticle size is used and compared to water as the base fluid. Test results show that the nanofluid improves heat transfer characteristics and heat transfer coefficient compared to water. Specifically, the effectiveness of the heat exchanger increased by 23.1% when using nanofluid versus water. Varying the mass flow rate was also found to impact the heat transfer rate and effectiveness.
The value of selecting the right catalyst
Selecting the key performance criteria
Sources of data:
Plant data
Laboratory reactor data
Catalyst characterization
Recommendations
ammonia water (NH3-H2o) diffusion vapor absorption refrigeration systemJagannath1234
1.Vapor absorption refrigeration system based on ammonia-water is one of the oldest refrigeration systems.
2.An absorption refrigeration system uses a heat source (e.g., geothermal energy, solar energy, and waste heat from steam plants, and even natural gas when it is at a relatively low price.) to provide the energy needed for the cooling process.
3.Quite similar to a vapor compression system.
4.The compressor is replaced by a generator and absorber.
5.Ammonia is used as a refrigerant i.e. R-717 and Water as an absorber.
6.Condensation, expansion and evaporation processes are the same as the VCR system.
Energy can neither be created nor be destroyed”- first law of thermodynamics. the energy
potential of the world is constant , so we have to save the energy as much as possible .as the refrigeration
is needed everywhere in the world and it is the major user of energy. The energy that could be used for
the adsorption refrigeration is powered by low grade heat. the low grade heat can be obtain from
industrial waste heat, exhaust gases from the engines or heat from solar thermal collector. Moreover it
uses environment kindly refrigerants and avoids the global warming and ozone depletion.
EXPERIMENTAL STUDY ON A DOMESTIC REFRIGERATOR USING LPG AS A REFRIGARANTIAEME Publication
This project is devoted to feasibility study of substitution of LPG (60% Propane and 40 % commercial Butane) as refrigerant instead of R134a in a domestic refrigerator. An experimental performance study on a VCR system
with LPG as refrigerant was conducted and compared with R134a.The VCR system was initially designed to operate with R134a.
Comparison of the Performances of NH3-H20 and Libr-H2O Vapour Absorption Refr...IJERA Editor
Developments in absorption cooling technology present an opportunity to achieve significant improvements on
micro-scale to buildings, cooling, heating and power systems for residential and light commercial buildings.
Their resultant effects are effective, energy efficient and economical. This study therefore contributes an
important knowledge and method in the development, fabrication and application of an absorption refrigerator as
a better alternative to the commonly used compressor refrigerators. Two fluid gas absorption refrigerators use
electric based heater installed generator and no moving parts, such as pumps and compressors, and operate at a
single system pressure. In this paper the performances analysis of the NH3-H2O and possible alternative cycles as
lithium bromide-water are compared in respect of the (COP) and different operating conditioning. The highest
COP was found as a function of the absorber, generator, condenser, and evaporating temperature. This paper
compares the performance of vapour absorption refrigeration cycles that are used for refrigeration temperatures
below 0°C. Since the most common vapour absorption refrigeration systems use ammonia-water solution with
ammonia as the refrigerant and water as the absorbent, research has been devoted to improvement of the
performance of ammonia-water absorption refrigeration systems in recent years
This document summarizes a study on an adsorption refrigeration system for truck cabin cooling using engine exhaust heat. The proposed system uses two adsorbers, two condensers and an evaporator connected with two control valves. Experimental testing of a 1 kW prototype showed a cooling capacity of 1-1.2 kW and a COP of 0.4-0.45. The system uses a compact design with minimal components, making it portable for truck integration. Graphs show the system's refrigeration capacity, COP and heating time vary with exhaust gas temperature. The study concludes the proposed system can provide refrigeration without impacting engine efficiency and is a viable option for truck cabin cooling.
To study the application of nanorefrigerant in refrigeration system a revieweSAT Journals
1. The document reviews the application of nanorefrigerants in refrigeration systems. Nanorefrigerants are a combination of nanoparticles and refrigerants that can improve heat transfer properties compared to conventional refrigerants.
2. Several studies are summarized that found improvements like increased heat transfer, higher COP, and reduced energy consumption when using nanorefrigerants made of particles like Al2O3, CuO, and TiO2 mixed with refrigerants like R134a and R600a.
3. The review concludes that nanorefrigerants show promise for making refrigeration processes more efficient and reducing their environmental impact, though more study is still needed to optimize nanoparticle type and concentration.
This document presents a theoretical and experimental analysis of a direct-fired double effect lithium bromide/water absorption chiller located at a lighting technology company in Egypt. The chiller has a cooling capacity of 500 tons and uses a parallel flow configuration. Temperature measurements were taken at various points in the chiller components in July 2013 and July 2014. Mathematical equations were developed to model the chiller and estimate the coefficient of performance and heat transfer rates based on temperature and flow rate data. Theoretical and experimental analyses were conducted to evaluate how the COP is affected by factors like heat exchanger effectiveness and circulation ratio. The results show that the chiller's COP was lower in 2014 compared to 2013, possibly due to degradation of the heat ex
VOLUME-7 ISSUE-8, AUGUST 2019 , International Journal of Research in Advent Technology (IJRAT) , ISSN: 2321-9637 (Online) Published By: MG Aricent Pvt Ltd
This document describes an experimental study on enhancing heat transfer in a domestic refrigerator using a nanofluid as the working fluid. Specifically, it investigates using a mixture of R600a refrigerant, mineral oil, and alumina nanoparticles (Al2O3) in a vapor compression refrigeration system. The addition of nanoparticles is intended to improve the thermophysical properties and heat transfer characteristics of the working fluid mixture. Experimental results found that using the nanofluid working fluid reduced power consumption by 11.5% compared to using POE oil alone, and increased the freezing capacity of the refrigerator. Thus the study demonstrates the feasibility of using Al2O3 nanofluids to enhance the performance of refrigeration systems.
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.
Thermodynamic analysis of vapour compression refrigeration system using alte...IOSR Journals
This document discusses thermodynamic analysis of alternative refrigerants for vapor compression refrigeration systems. It aims to analyze the environmental and energy consumption impacts of various refrigerants. The document defines key terms like ozone depletion potential and global warming potential. It then analyzes several potential refrigerant alternatives to R22 and R134a like propane, isobutane, R410a, R407c, and a mixture called MO9. The thermodynamic properties of these refrigerants are obtained from software and their coefficients of performance are compared. The analysis found that MO9 shows potential as a suitable substitute for R134a in new and retrofit systems due to its performance and lower environmental impact.
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
PERFORMANCE ENHANCEMENT OF HOUSEHOLD REFRIGERATOR BY USING TiO2 NANO LUBRICAN...Niyas PP
The document describes experiments conducted to enhance the performance of a household refrigerator by adding TiO2 nanoparticles to the compressor oil. Three experiments were performed: 1) with PAG oil, 2) with SUNISO 3GS oil, and 3) with SUNISO 3GS oil mixed with 0.05% TiO2 nanoparticles. Results showed that actual COP increased by 21% with pure SUNISO 3GS oil and by 35% with the nano-lubricant oil mixture compared to PAG oil. Power consumption was also reduced by 17.25% with pure SUNISO 3GS oil and 25.83% with the nano-lubricant oil. The nano-lubricant improved heat transfer and reduced friction inside the
Experimental Study and CFD Analysis of Thermal Performance Improvement of Car...IRJET Journal
This document summarizes an experimental study and CFD analysis of using MgO/water nanofluid to improve the thermal performance of a car radiator. Experiments were conducted to test different volume fractions of MgO/water nanofluid and measure its thermal properties and heat transfer rate in the radiator. CFD simulations were also performed to validate the experimental temperature distributions. The results showed that using MgO/water nanofluid as the coolant led to higher heat transfer rates and outlet temperatures in the radiator compared to using just water, with enhancements of up to 70% observed, and the performance increased with higher nanoparticle volume fractions.
Experimental Study of Heat Transfer Enhancement in Triple Tube Heat Exchanger...IRJET Journal
The document describes an experimental study of heat transfer enhancement in a triple tube heat exchanger using CuO and Al2O3 nanofluids. A triple tube heat exchanger was tested with hot water flowing through the intermediate tube and cold water flowing through the inner and outer tubes. Nanofluids of CuO and Al2O3 with a 0.033% volumetric concentration were used. The heat transfer rate and effectiveness of the triple tube heat exchanger were evaluated experimentally for different flow rates of the hot fluid, with the cold fluid flow rate held constant. The results showed that use of nanofluids increased the heat transfer rate and effectiveness compared to using plain water as the working fluid.
The document describes the design of a batch stirred tank reactor for producing industrial alcohol through fermentation. Key details include:
- The reactor will be a jacketed, stirred tank reactor with a volume of 377m3, 10m height, 6.8m diameter, and carbon steel construction.
- It will operate at 32°C and 1.8 atm with a 52 hour batch time and use a torispherical head.
- Cooling will be provided by a 17m2 jacket using 33 tons/hr of cooling water from 20-28°C.
- Agitation will be from three 6-bladed impellers 2.2m in diameter running at 44 RPM and requiring 60
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The value of selecting the right catalyst
Selecting the key performance criteria
Sources of data:
Plant data
Laboratory reactor data
Catalyst characterization
Recommendations
ammonia water (NH3-H2o) diffusion vapor absorption refrigeration systemJagannath1234
1.Vapor absorption refrigeration system based on ammonia-water is one of the oldest refrigeration systems.
2.An absorption refrigeration system uses a heat source (e.g., geothermal energy, solar energy, and waste heat from steam plants, and even natural gas when it is at a relatively low price.) to provide the energy needed for the cooling process.
3.Quite similar to a vapor compression system.
4.The compressor is replaced by a generator and absorber.
5.Ammonia is used as a refrigerant i.e. R-717 and Water as an absorber.
6.Condensation, expansion and evaporation processes are the same as the VCR system.
Energy can neither be created nor be destroyed”- first law of thermodynamics. the energy
potential of the world is constant , so we have to save the energy as much as possible .as the refrigeration
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SMARTView software environments. The experimental results
revealed that the homogeneous porous media, in addition to
its convective heat exchange with the gas, might absorb, emit,
and scatter thermal radiation. The rate of heat transfer was
more at the center of the burner where a combined effect of
both convection & radiation might be realized. The maximum
thermal efficiency was found to be 64% which was having a
good agreement with the previous data in the open literature.
The document describes a water cooling system that uses engine exhaust heat from a two-wheeler engine. The system uses an adsorber bed filled with activated carbon to adsorb R134a refrigerant. Exhaust from the engine passes through the adsorber bed, heating it and causing the refrigerant to evaporate. The evaporated refrigerant then passes through a coil that acts as an evaporator, cooling water passed through it. After condensing, the refrigerant is expanded through a valve and re-adsorbed in the bed, completing the cycle. Experimental results showed the system could cool 2 liters of water to 19°C within 30 minutes, using only waste heat from the engine exhaust. The system provides
A heat pipe heat exchanger is a simple device which is made use of to transfer heat from one location to another, using an evaporation-condensation cycle.
A passive solar system heat-driven convection or heat pipes to circulate the working fluid. Passive systems cost less and require low or no maintenance, but are less efficient. Overheating and freezing are major concerns.
An active solar system use one or more pumps to circulate water and/or heating fluid. This permits a much wider range of system configurations.
IJERD (www.ijerd.com) International Journal of Engineering Research and Devel...IJERD Editor
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This document summarizes a study on the thermal performance of a shell and tube heat exchanger using nanofluids. Finite volume modeling was used to analyze heat transfer and flow characteristics. Various nanofluids including Ag, Al2O3, CuO, SiO2, and TiO2 suspensions in water were tested and compared to pure water. The objectives were to analyze temperature profiles, heat transfer coefficients, pressure drops, and effectiveness. Results showed nanofluids had higher overall temperatures indicating more heat transfer compared to water alone. This study analyzed the potential for nanofluids to enhance heat exchanger performance.
Adsorption of hydrogen sulfide using palm shell activated carboneSAT Journals
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An Experimental Investigations of Nusselt Number for Low Reynolds Number in a...IJMER
This document summarizes an experimental investigation of heat transfer in an agitated vessel with a helical coil. Key points:
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ARTICLE 58 IJAET VOLII ISSUE III JULY SEPT 2011Nirav Soni
The document reports on an experimental investigation of a double pass solar air heater with a corrugated absorber plate and Amul Cool aluminum cans. The study found that using a corrugated plate and aluminum cans in the double pass design increased the absorber plate temperature and thermal efficiency compared to a conventional single pass solar air heater. Tests were conducted to analyze how factors like time of day, solar insolation, and mass flow rate affected the absorber temperature and thermal efficiency of the modified solar air heater design.
IRJET- R134a Refrigerant in Vapour Compression Cycle: A Review PaperIRJET Journal
This document provides a review of R134a refrigerant used in vapor compression cycles. It discusses the properties and environmental impacts of R134a including its zero ozone depletion potential but relatively high global warming potential. The document then reviews potential alternative refrigerants to R134a such as CO2, HFC-152a, R32, and R152a. It evaluates their physical and chemical properties including boiling points, ozone depletion potentials, and global warming potentials. The document aims to identify efficient, eco-friendly, and safe refrigerants that can be used as alternatives to R134a in the future.
CFD investigation on heat transfer enhancement in shell and tube heat exchang...IRJET Journal
The document discusses a computational fluid dynamics (CFD) investigation of heat transfer enhancement in a shell and tube heat exchanger using graphene oxide (GO) nanofluid. A 3D model of a shell and tube heat exchanger is developed and GO nanofluid is introduced. Governing equations are solved numerically to analyze heat transfer performance. Results show that incorporating GO nanofluid leads to enhanced heat transfer compared to traditional fluids due to GO's higher thermal conductivity and its ability to disrupt thermal boundary layers and promote mixing. Heat transfer rate increased 42% and convective heat transfer coefficient increased 62% with GO nanofluid. This suggests GO nanofluid can significantly improve heat exchanger efficiency for applications like power plants and HVAC systems. Further
Study & Review of Heat Recovery Systems for SO2 Gas Generation Process in Sug...IRJET Journal
This document summarizes a study on heat recovery systems for the SO2 gas generation process in the sugar industry. It begins with an introduction to waste heat recovery and its importance. It then reviews various methods for recovering waste heat. The document discusses factors that affect waste heat recovery systems like heat quantity and quality. It reviews several past studies on waste heat recovery in different industries. It proposes studying heat recovery from the SO2 gas generation process in sugar production to make the process more efficient. The conclusion emphasizes the need for waste heat recovery techniques in industries to conserve energy.
Performance Improvement Of Self-Aspirating Porous Radiant Burner By Controlli...BIBHUTI BHUSAN SAMANTARAY
This document summarizes an experimental study on improving the performance of a self-aspirating porous radiant burner (SAPRB) by controlling process parameters such as gas velocity. The study used an experimental setup including a two-layer SAPRB, thermocouples, an IR camera, and data acquisition systems to measure temperature profiles at different flame zones. Results showed that the maximum temperature and heat transfer rate increased with higher gas velocity due to combined convective and radiative heat transfer. The maximum thermal efficiency achieved was 64% which agrees with previous literature. Process parameters like gas velocity can be controlled to improve SAPRB performance.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
In this paper, a mathematical model is developed to study the performance of a parabolic trough collector (PTC). The proposed model consists of three parts. The first part is a solar radiation model that used to estimate the amount of solar radiation incident upon Earth by using equations and relationships between the sun and the Earth. The second part is the optical model; This part has the ability to determine the optical efficiency of PTC throughout the daytime. The last part is the thermal model. The aim of this part is to estimate the amount of energy collected by different types of fluids and capable to calculate the heat losses, thermal efficiency and the outlet temperature of fluid. All heat balance equations and heat transfer mechanisms: conduction, convection, and radiation, have been incorporated. The proposed model is implemented in MATLAB. A new nanofluids like Water+PEO+1%CNT, PEO+1%CNT and PEO+0.2%CUO where tested and were compared with conventional water and molten salt during the winter and the summer to the city of Basra and good results were obtained in improving the performance of the solar collector. The results explained both the design and environmental parameters that effect on the performance of PTC. Percentage of improvement in the thermal efficiency at the summer when using nanofluids (Water+PEO+1%CNT, PEO+1%CNT and PEO+0.2%CUO) Nano fluids are (19.68%, 17.47% and 15.1%) respectively compared to the water and (10.98%, 8.93% and 6.7%) respectively compared to the molten salt, as well as the percentage decreases in the heat losses by using the Nano fluids through the vacuum space between the receiver tube and the glass envelope compared with water (86 %, 76 % and 66 %) and molten salt (79.15 %, 64.34 % and 48.47 % ) . As final a Water+PEO+1%CNT nanofluid gives the best performance
Performance Evaluation of U-Tube Pulsating Heat Pipe with Water-Based Nanofl...Adib Bin Rashid
The safety and efficiency of electronic equipment are becoming increasingly
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equipment is shrinking as it becomes more integrated. Hence, the heat load per
unit area increases, and the standard heat dissipation method may not fulfill their
requirements. Therefore, Pulsating Heat Pipe plays an essential role in efficiently
removing heat from congested surfaces to satisfy the requirement. To find
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pressure. In this work, various experiment is carried out with water-based
Aluminum Oxide, Zinc Oxide, and Graphene Oxide Nanofluids. This work will help
upgrade PHP's performance and thus help enhance heat transfer performance
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Experimental Investigation on Adsorption Capacity of a Variety of Activated Carbon/Refrigerant Pairs
1. Ahmed N. Shmroukh et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 4, ( Part -6) April 2015, pp.66-76
www.ijera.com 66 | P a g e
Experimental Investigation on Adsorption Capacity of a Variety
of Activated Carbon/Refrigerant Pairs
Ahmed N. Shmroukh*, Ahmed Hamza H. Ali**, Ali K. Abel-Rahman* and S.
Ookwara **
*(Energy Resources Engineering Department, Egypt- Japan University of Science and Technology E-JUST,
New Borg Elarab, Alexandria 21934, Egypt)
**(Mechanical Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt)
*** (Department of Chemical Engineering, Graduate School of Science & Engineering, Tokyo Institute of
Technology, Tokyo 152-8552, Japan)
ABSTRACT
This study aims to develop a device with minimum heat and mass transfer limitations between adsorbent and
adsorbate, and subsequently to obtain practically applicable adsorption capacity data. Also, 5 kW adsorption
chillers (evaporators, condensers and adsorbers) are designed based on the experimental output data of the whole
tested pairs. A finned-tube heat exchanger was employed and installed at the center adsorber, and each employed
adsorbent was immobilized on its surfaces by using an adhesive agent. A variety of pairs: are activated carbon
powder (ACP)/R-134a, ACP/R-407c, ACP/R-507A, activated carbon granules (ACG)/R-507A, ACG /R-407c
and ACG /R-134a, were examined at different adsorption temperatures of 25, 30, 35 and 50°C. It was found that,
at the adsorption temperature of 25°C the maximum adsorption capacity was 0.8352 kg kg-1
for ACP/R-134a,
while at the adsorption temperature of 50°C the maximum adsorption capacity was 0.3207 kg kg-1
for ACP/R-
134a. Therefore, the ACP/R-134a pair is highly recommended to be employed as adsorption refrigeration
working pair because of its higher maximum adsorption capacity higher than the other examined pairs.
Keywords - Adsorption; Adsorbent/Adsorbate Pairs; Adsorption Capacity; Refrigeration
I. Introduction
The development of adsorption refrigeration
technology is recently paid much attention. It was
favorably argued that such sorption systems were
quiet, long lasting, cheap to maintain and
environmentally benign [1]. A vital and important
component in the adsorption refrigeration system is
adsorption refrigeration working pair, of which the
developments directly lead to the performance
improvement of the adsorption refrigeration systems.
Therefore, the utilization of adsorption
refrigeration technology is a first step toward
developing an energy efficient and environmental
friendly air conditioning and refrigeration systems.
The second step is to employ an effective refrigerant
with the solid adsorbent, which has lower
environmental impact with higher adsorption
capacity than the available pairs. The adsorption
cooling and refrigeration systems have the
advantages of being free of moving parts, efficiently
driven by low-temperature waste heat or renewable
energy sources and do not require any synthetic
lubricants [2]. Askalany et al. [3] presented a review
on adsorption cooling systems with adsorbent pairs of
activated carbon (AC) with ammonia, methanol,
ethanol, hydrogen, nitrogen and diethyl, ether pitch
based AC (Maxsorb III) with R134a, R507A and n-
butane and AC/CO2 respectively. Their review
showed that the highest adsorption capacity of 0.055
g g-1
at 30 °C and 6 bar for AC/hydrogen pair, 0.75 g
g-1
at -4 °C for activated carbon fibers/nitrogen pair,
0. 00139 g g-1
at 50 °C and 0.1 bar for AC/diethyl
ether, 2 g g-1
at 30 °C and 8 bar for AC/R134a, 1.3 g
g-1
at 20 °C for AC/R507a, 0.8 g g-1
at 35 °C and 2.3
bar for AC/n-butane and 0. 084 g g-1
at 30 °C and 1
bar for AC/CO2 pair respectively. They also
concluded that the maximum Coefficient of
Performance (COP) of the cooling systems was 0.8
for AC/ethanol pair and the performances possible
adsorption cooling systems with carbon are still not
satisfactory. In their review, it can be noted that the
refrigerants of R134a and R507a have high global
warming potential (GWP), while n-butane, hydrogen,
methanol, ethanol and diethyl ether are highly
flammable gases, and further, ammonia is a highly
toxic refrigerant. Solmus et al. [4] have successfully
conducted a numerical investigation of coupled heat
and mass transfer inside the adsorbent bed of a silica
gel/water adsorption cooling unit, by employing the
local volume averaging method. They developed a
transient one-dimensional local thermal non-
equilibrium model, which accounts for both internal
and external mass transfer resistances. Askalany et al.
[5] have carried out an experimental study on
adsorption-desorption characteristics of granular
activated carbon/R134a pair. Throughout their
RESEARCH ARTICLE OPEN ACCESS
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experiments the temperature of the pairs was about
25 ºC. Thier experimental results [5] showed that an
increase in the adsorbent temperature of the
adsorbent leads to a decrease in the maximum
adsorption capacity to 0.53 kgR134a kgcarbon-1
at
60°C in a period of 450 s. The maximum adsorption
capacity was found to be 1.68 kgR134a kgcarbon-1
at
25°C after 1000 s. They also concluded that the
granular activated carbon and R134a could be used as
an adsorption pair in an adsorption cooling system.
Shmroukh et al. [6] made comparison and gave
summary of the state-of-the-art in the application of
the adsorption refrigeration working pairs from both
classical and modern adsorption pairs. They reported
that the maximum adsorption capacity for the
classical working pairs was 0.259 kg kg-1
for
AC/methanol while that for the modern working pairs
was 2 kg kg-1
of maxsorb III/R-134a. They also
concluded that, the performances of existing
adsorption working pairs in adsorption cooling
systems are still needs further to be enhanced while
the development of novel adsorption pairs having
higher sorption capacity with low or no impact on
environmental is necessary, to build an adsorption
chiller that is compact, efficient, reliable and long life
performance adsorption chiller. Moreover, future
researches need to be focused on designing the
adsorption system that provide efficient heating and
cooling for the adsorbent materials by immobilizing
the adsorbent material over heat exchanger surface,
to allow good heat and mass transfer between the
adsorbent and the refrigerant.
In the literature, it can be seen that all the
experimental studies on adsorption capacity
experiments were carried out on packed bed
adsorbers, which could have dead zones inside and
resultantly lacking efficient heat and mass transfer.
Since such experiments with packed bed could
produce inapplicable data, for example, very high
values of adsorption pairs capacity which deviate
from the real adsorption refrigeration systems.
Therefore, the present study focuses on developing a
device with minimum heat and mass transfer
limitations between adsorbent and adsorbate to obtain
practically applicable adsorption capacity data. For
this purpose, a finned-tube heat exchanger was
employed as a main part located at the center of the
adsorber and adsorbate was immobilized over its
surface by using adhesive agent. The main objective
of the present experimental study is to experimentally
evaluate the maximum adsorption capacity of six
different adsorption refrigeration working pairs. The
pairs of activated carbon powder (ACP)/R-134a,
ACP/R-407c, ACP/R-507A, activated carbon
granules (ACG)/R-507A, ACG/R-407c and ACG/R-
134a, were examined at different adsorption
temperatures of 25, 30, 35 and 50 °C.
II. Experimental Setup, Measurements,
Procedures, Data Reduction and
Error Analysis
2.1 Experimental Setup
A detailed schematic diagram of the test facility
with the adsorber (adsorbent tank) heat transfer core
is presented in Fig. (1). The test facility mainly
consists of adsorber, refrigerant tank, water tank,
vacuum pump and piping system.
Fig.1: Schematic diagram of the experimental setup
of this study, 1) Adsorber, 2) Heat exchanger core, 3)
Cooling and heating Water tank, 4) Refrigerant
container, 5) Refrigerant charging valve, 6) Water
flow control valve, 7) Refrigerant charge/discharge
control valve, 8) Electronic balance.
The adsorber outer frame is a 2mm thickness
galvanized steel tank with dimensions of 7*5*23 cm.
It is insulated by a 2.5 cm thickness glass wool and
foam insulators, and it contains the adsorbent heat
and mass transfer core that shown in Fig. (2). The
adsorbent heat and mass transfer core is a rectangular
aluminum fin and tube heat exchanger with a copper
tube and the adsorbent material is immobilized over
the heat exchanger outer surface.
(a) (b)
(c)
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(d)
Fig.2: Heat exchanger core assembly (a) temperature
measuring points, (b) Photograph before adhesive the
adsorbent, (c) Photograph after adhesive the activated
carbon powder and (d) Photograph after adhesive the
granular activated carbon.
The refrigerant container is a 2mm thickness
galvanized steel tank with 10*10*20 cm in
dimension, the refrigerant charging valve is welded
to its top. The tank is insulated by a 2.5 cm thickness
glass wool insulator. The Charged refrigerant is from
DuPont company refrigerant (canned in Egypt by
Rizk Brothers company), the refrigerant properties
extracted from tables downloaded from the official
website of DuPont company.
The water tank is a 2mm thickness galvanized
steel tank with 30*30*30 cm in dimension with its
cover. It is equipped by a water heater and a
thermostat. Cooling and heating water is stored in
this tank, to initiate the adsorption and desorption
processes. The tank is insulated by a 2.5 cm thickness
glass wool insulator. The flowing water temperature
is adjusted by a thermostat ranging from 0 °C to 200
°C, with uncertainty of ± (0.625% of full scale), it is
connected by a contactor to connect and separate the
heating coil of 1 kW which fixed at the bottom of the
water tank at the required temperature. All the system
main components and pipes are insulated by glass
wool and insulation foam.
The adsober is vacuumed by a vacuum pump
that is a single-phase RV3 type. This vacuum pump
used for vacuuming the system before each
adsorption experiment, preventing air presence in the
system, to assure that the whole gas in the system is
the refrigerant only.
2.2 Measurements
In this section a brief description of the
instruments used for measuring the temperature, flow
rate and pressure are given. All temperatures have
been measured by using type T thermocouple
(copper, constantan). The voltage output was
introduced to a data acquisition device (NEC,
DC6100 model) having a maximum of 60 channels,
which by turn is connected to a computer for
controlling and recording the measured temperature
data of measuring points at the same time. Two sizes
of thermocouple wires were used; the first size is a
0.1 mm in diameter, which has the junction in contact
with the component which temperature is to be
measured. The second type is an extension
thermocouple wire (Type T) of diameter 0.32 mm,
used to connect the 0.1 mm wire diameter
thermocouple some distance away from the
component, to keep the splicing junction from being
heated using the method used by Ali and Hanaoka
[7], which might results in secondary effects that
change the temperature reading to the data
acquisition device.
All thermocouple junctions had uncertainty of ±
(0.05% of reading +0.5 °C), these thermocouple
junctions made by removing the insulation layer by
using fine sanding sheet then twisting the wire ends,
then the junctions were connected to the needed
measuring points by a very thin adhesive epoxy layer.
The refrigerant pressure was measured by a
pressure gauge fixed on the top of the adsorber. The
range of this gauge was from -1 to 15 bar absolute,
with uncertainty of ±0.25 bar or ± (0.833% of full
scale).
The mass of the refrigerant entering the
adsorbent tank is measured by an electronic balance
of 10 kg maximum reading and 0.1g sensitivity, with
uncertainty of ± 0.1g or ± (0.001% of full scale).
The volume flow rate of the water exiting from
water tank to the adsorbent tank is adjusted to be
(0.33 l min-1
), it is measured by laboratory graded
glass bottle (500 ml with 5 ml minimum scale), with
uncertainty of ± 5ml or ± (1% of full scale) and stop
watch.
2.3 Experimental procedures
For all experiments, the following procedure was
followed:
1. All the 16 points thermocouples (Type T) are
connected by plugs and connectors to the same
type leading wires to the data logger.
2. The whole system is evacuated (charging tank,
adsorbent tank and piping system) by a vacuum
pump to the minimum possible vacuum pressure
(25-30 kPa). The adsorber weight is recorded
after this step.
3. The target refrigerant for the experiment is
charged to the refrigerant container by the
charging valve at the top of the container, this
container is weighted during charging process
until charging 100 g of refrigerant.
4. The charging valve is then closed tightly to
prevent refrigerant leakage.
5. The adsorbent tank pressure is measured by the
pressure gauge.
6. The mass of the refrigerant entered the adsorbent
tank is measured by the electronic balance.
7. The flow rate of water exiting from water tank to
the adsorbent tank is measured by laboratory
graded glass bottle.
8. The water tank is filled to a fixed level then its
valves are closed and the heating process takes
place to the required temperature. After that,
inlet valve to water tank and exit valve to
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adsorbent tank are opened to the specific water
flow rate.
9. The electronic balance is operated and the data
logger is connected to the computer to present
the data, and the reading interval is set to be
every 60 sec. This step is continues until both the
balance and thermocouples readings are stable
and reach steady state.
10. For the adsorption experiments, the refrigerant
container valve is slightly opened then the
adsorption process readings are started until the
balance reading reach to a constant value. This
means the adsorption equilibrium or the
adsorbent material cannot adsorb more
refrigerant. Then the adsorbent tank is evacuated
by the vacuum pump to draw out all un-adsorbed
refrigerant mass, which was fills the adsorbent
tank internal space. This to ensure that there is
no refrigerant mass inside the tank except the
adsorbed refrigerant quantity. Then the flexible
pipe which fixed at the top of the tank is
disconnected and the adsorber tank is weighted
by the balance. The weight difference between
step 2 and this step reading is considered as the
exact adsorbed refrigerant quantity. Then the
flexible pipe is reconnected and evacuated before
open the adsorbent tank valve to reject air, then
the valve is opened to be ready for desorption
experiment.
11. For the desorption experiment, the refrigerant
will return back to its tank by heating the
adsorbent. This process is continued until all the
adsorbed refrigerant is desorbed from the
adsorbent tank and the balance reading reach to
be stable and fixed value that nearly equal or a
little bit more than the adsorption experiment
initial reading. This slightly higher is due to the
residual refrigerant in adsorbent pores
(hysteresis) which is difficult to rejected by
desorption only but need vacuum process.
12. The adsorbent tank valve is closed and the
flexible houses are disconnected and the tank is
left until reach stable weight reading. Finally, the
flexible houses are reconnected and evacuated
before opening the adsorbent tank valve in order
to reject air. After that, the valve is opened and
the test rig is ready for a new experiment.
13. The number of performed adsorption and
desorption experiments were 50 (20 adsorption
experiments and 30 desorption experiments).
The controlled variable in these experiments
were the adsorption and desorption temperatures.
The adsorption temperatures were 25 °C, 30 °C,
35 °C and 50 °C while the desorption
temperatures were 70 °C, 80 °C and 85 °C
respectively. The adsorption and desorption
conditions chosen to nearly simulate the actual
operating conditions in the practical adsorption
refrigeration systems.
The activated carbon powder adsorbent
(Norit SA SUPER) used in the experiments was
provided by Norit Nederland B.V. Company [Norit
Data Sheets]. It was with an extra fine particle size
and it was produced by steam activation of
dedicated vegetable raw materials. The quantity of
activated carbon powder adsorbent used in the
experiments was 44.9 g. Its characteristics are
summarized in the following table 1: The granular
activated carbon adsorbent (Norit GCN 1240) used in
the experiments was provided by Norit Nederland
B.V. Company [Norit Data Sheets]. It was produced
from coconut shells by steam activation. The quantity
of granular activated carbon adsorbent used in the
experiments was 139.6 g. Its characteristics are
summarized in the following Table 2:
Table 1. Activated carbon powder characteristics
Total surface area 3150 m2
g-1
Apparent density 250 m3
kg-1
Average particle size 5 µm
Table 2. Granular activated carbon characteristics
Total surface area 1150 m2
g-1
Apparent density 510 m3
kg-1
Average particle size 0.6 Mm
The refrigerants which used with this adsorbent were:
1. R-134a which is a Hydrofluorocarbon (HFC), its
GWP (global warming potential) is 1300 and it
has zero ODP (ozone depletion potential) [8].
2. R-507A which is an Azeotropic mixtures, it is
consists of two refrigerants (HFC-143a 50% and
HFC-125 50% by weight) having different
properties but behaving as a single substance, its
GWP (global warming potential) is 3300 and it
has zero ODP (ozone depletion potential) [8].
3. R-407c which is a Nonazeotropic mixtures, it is
consists of three refrigerants (HFC-32 23%,
HFC-125 25% and HFC-134a 52% by weight)
having different volatiles, its GWP (global
warming potential) is 1526 and it has zero ODP
(ozone depletion potential) [8].
2.4 Data Reduction
Refrigerant adsorbed mass is obtained from
simple subtraction equation, which was used to
determine the mass of the adsorbed refrigerant in
adsorption capacity experiment of certain adsorption
pair, the initial mass of the adsorption bed subtracted
from the final mass of the whole adsorption bed after
each run as follows.
mRef = mBed – minitial (1)
Where mRef is the adsorbed refrigerant in kg,
mBed is the final adsorption bed mass after each run in
kg and minitial is the initial mass of the adsorption bed
before the experiment in kg.
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Adsorption pairs capacity is obtained from simple
dividing equation to determine the adsorption
capacity of each adsorption pair, as the mass of the
adsorbed refrigerant in the adsorbent material divided
by the mass of the adsorbent as follows.
X = (2)
Where X is the adsorption capacity of the tested
working pair in kgRef kgads
-1
, mRef is the mass of the
adsorbed refrigerant in kg and mads is the initial mass
of the adsorbent in the adsorption bed in kg.
2.5 Adsorption Chiller Design
A 5 kW adsorption chiller is designed based on
the experimental output data. The three main
components which are the condenser, the evaporator
and the adsorber designed based on the following
steps.
2.5.1 Condensers and Evaporators Design
The previously mentioned equations in chapter
three are the needed equations for designing the shell
and tube condensers and evaporators of the 5 kW
adsorption chiller, for the whole tested six pairs,
assuming that the condensers and evaporators
temperatures are 40 °C and 10 °C respectively. Using
the same concept and steps used in chapter three,
assuming that the condenser cooling water inlet
temperature is 25 °C and cooling water outlet
temperature is 35 °C, and the evaporator chilled
water inlet temperature is 22 °C and chilled water
outlet temperature is 12 °C, the whole output data for
designing the condensers and the evaporators of the
experimentally tested adsorption pairs for chiller with
5 kW cooling capacity, a reference SorTech chiller
with 15 kW cooling capacity and a reference SorTech
chiller with 5 kW cooling capacity, are shown in
tables 3 & 4 respectively.
*For condenser: The condensing power can be
calculated from the following equation
CondLMTDocondfCWCWCWCond TAUhhmTCpmQ )(*** 21Re
(3)
Where CondQ is the condenser load in kW, CWm is
the condenser cooling water mass flow rate kg/s,
CWT is the condenser cooling water temperature
difference in K, fmRe
is the refrigerant mass flow
rate kg/s, oUA is the overall thermal conductance in
W/K and
CondLMTDT is the logarithmic mean
temperature difference in K. Assuming that cooling
water inlet temperature is 25 °C and cooling water
outlet temperature is 35 °C.
*For evaporator: The refrigeration power or the
cooling capacity can be calculated from the following
equation
evLMTDoevfChWChWChWev TAUhhmTCpmQ )(*** 34Re
(4)
Where evQ is the evaporator cooling load in kW,
ChWm is the chilled water mass flow rate kg/s,
ChWT is the evaporator chilled water temperature
difference in K. Assuming that chilled water inlet
temperature is 22 °C and chilled water outlet
temperature is 12 °C.
The logarithmic mean temperature difference can be
calculated from the following equation
)ln(
)()(
11
22
1122
ch
ch
chch
LMTD
TT
TT
TTTT
T
[9, 10] (5)
The condenser or evaporator tubes heat transfer outer
area can be calculated by the following equation
passtubetubetubeoo NLndA **** (6)
Where tubeod is the tube outer diameter in m, tuben is
the tubes number, tubeL is the tube length in m,
assuming that it doesn’t exceed 1m with single pass
and passN is the number of tube passes.
The condenser or evaporator tubes area can be
calculated by the following equation
tubetubetube ndA *
4
(7)
The cooling or chilled water velocity can be
calculated by the following equation
tubeA
m
v
*
(8)
Where is the chilled water density in kg/m3
.
The condenser or evaporator shell diameter can be
calculated by the following equation
]
)(
[637.0
2
tube
tubeoo
shell
L
dPRA
CPT
CL
D [9] (9)
Where CL, CLP and PR are tube layout constant,
shell constant and pitch ratio respectively.
The hydraulic diameter of the condenser or
evaporator tubes can be calculated by the following
equation
]4
)(
[4
22
tubeo
H
d
dPitch
D
tubeo
[9] (10)
The overall heat transfer coefficient of the condenser
or evaporator tubes can be calculated by the
following equation
otube
tube
tubeo
tubeo
itube
tubeo
hk
d
d
d
hd
d
U
1
2
)ln(*
1
[9,10] (11)
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*For shell side:
3/155.0
Pr*Re*36.0Nu [9, 10] (12)
)
)(
(
Re
Re
Re
pitch
BdpitchD
Dm
tubeoshell
f
Hf
[9]
Where B is the baffle spacing in m which equal 0.4 to
0.6 of the shell diameter.
H
f
o
D
k
Nuh
Re
[9,10] (13)
*For tube side:
3/2
Pr)Re(04.01
Pr)Re(0668.0
66.3
tube
tube
tube
tube
L
d
L
d
Nu
[10] (14)
for laminar flow
3.08.0
Pr*Re*027.0Nu [10] (15)
for turbulent flow
tube
f
d
k
Nuh
Re
1 [10] (16)
Table 3 adsorption chillers condensers data
R-
134
a
R-
407c
R-
507A
H2O
H2
O
coolingQ (k
W)
5 5 5 5 15
condQ (k
W)
5.5
17
5.397
7
5.470
8
5.11
545
15.
346
CWm (kg/
s)
0.1
31
0.129
1
0.130
85
0.12
235
0.3
67
fmRe
(kg/
s)
0.0
33
0.032
07
0.047
0.00
212
6
0.0
063
tubed (m)
0.0
15
0.015 0.015
0.01
5
0.0
15
tuben 22 22 22 100 250
passN 10 10 10 10 10
tubeL (m)
0.8
27
0.852
25
0.517
44
0.94
829
7
1.0
351
shellD (m)
0.4
32
0.432 0.432
0.92
235
3
1.4
583
Table 4 adsorption chillers evaporators data
R-
134
a
R-
407c
R-
507A
H2O H2O
coolingQ (k
W)
5 5 5 5 15
ChWm (kg/
s)
0.1
19
0.119 0.119 0.119
0.39
87
fmRe
(kg/
s)
0.0
33
0.032
07
0.047
0.0021
26
0.00
63
tubed (m)
0.0
15
0.015 0.015 0.015
0.01
5
tuben 20 20 20 28 70
passN 6 6 6 6 6
tubeL (m)
0.8
67
0.873
37
0.721
65
0.8362
92
0.94
12
shellD (m)
0.3
19
0.319 0.319
0.3780
52
0.59
77
4.5.2 Adsorber Design
The following table.5 containing the output data
for designing the adsorber of the experimentally
tested adsorption pairs for chiller with 5 kW cooling
capacity, reference SorTech chiller with 15 kW
cooling capacity, reference SorTech chiller with 5
kW cooling capacity and the theoretically tested
adsorption pair for chiller with 5 kW cooling
capacity. The designed chillers adsorber dimensions
was obtained by comparing the area needed for the
mass of adsorbent needed in the designed 5 kW
chiller to the mass of adsorbent already contained in
the tested adsorbent bed with its area. Using the same
steps of chiller design that were previously
mentioned in chapter three, taking into account that
the mass of adsorbent in ACG and ACP adsorption
bed were 139.6 g and 44.9 g respectively.
The area of the adsorption bed heat exchanger was
2
. 106425.0 mA ExcH
The cooling capacity of the designed 5 kW
adsorption chiller was
kWQev 5
The mass flow rate of the refrigerant in the designed
5 kW adsorption chiller was
skg
h
Q
m
ev
ev
f /Re
(17)
Where Δhev is the evaporator refrigerant enthalpy
difference in kJ/(kg.K)
The refrigerant mass in the designed adsorption
chiller was
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www.ijera.com 72 | P a g e
kg
t
m
m
cycle
f
f
Re
Re
(18)
Where tcycle is the adsorption-desorption cycle time in
sec
The adsorbent mass needed in the designed
adsorption chiller was
Table 5 adsorption chiller adsorber design data
kg
W
m
m
ads
f
ads
Re
(19)
Where Wads is the adsorption capacity of the pair
used in the designed adsorption chiller in kg/kg
The area of the heat exchanger adsorber of the
designed adsorption chiller was
2.*
m
m
Am
A
Ac
ExcHads
Bed (20)
Number of small heat exchanger units needed for to
accommodate the designed adsorption chiller was
ExcH
Bed
A
A
N
.
(21)
2.6 Error Analysis
The adsorbed refrigerant and the adsorption
capacity values are determined values as they are not
measured directly. Therefore, there are errors in their
values, however, the error analysis for these
determined values are calculated by using the
following general method for propagating
uncertainties through calculations [11].
2
i
2
22
2
11z )E+(.....)E+()E+(E i (22)
ix
z
i
(23)
Where Ei is the uncertainty in quantity xi and z is the
result.
The whole uncertainty analysis is presented in Tables
6 and 7.
Table 6. Error analysis of the measured parameters
Variable Symbol Error
Temperature T
± 0.05 % of reading +
0.5 °C
Pressure P ± 0.25 bar
Water flow rate Qw ± 5 ml
Adsorption bed
final mass
mBed ± 0.1g
Adsorption bed
initial mass
minitial ± 0.1g
Table 7. Error analysis of the determined
parameters
Variable Symbol Error
Refrigerant
Mass
mRef
± 0.141361541 g or ± 1 %
of the result
Adsorption
Capacity
X
± 0.000124624 g g-1
or
± 0.067056106 % of
the result
III. Results and discussion
For ACP / R-407c pair, Figure (3) indicates the
relation between the measured adsorbent temperature
inside the adsorber and water outlet from the
adsorber with time in 25 °C adsorption mode. The
adsorbent temperature inside the adsorber increased
in the beginning of the adsorption processes, due to
R-
134a /
ACG
R-134a
/ ACP
R-407c /
ACG
R-407c /
ACP
R-507A /
ACG
R-507A /
ACP
H2O /
Silica-
gel
H2O /
Silica
-gel
coolingQ (kW
)
5 5 5 5 5 5 5 15
No. adsorber
/ chiller
2 2 2 3 3 2 2 2
asdm
/bed (kg) 28.48 10.93 72.92 26.85 168.7 31.2 7.22 22.32
asdA
/bed (m2
) 27.1 25.9 55.6 63 128.6 73.96 50.47 151.4
Dim.
(m
m)
0.6*
0.35*
0.26
0.6*
0.35*
0.31
0.6*
0.35*
0.68
0.6*
0.35*
0.78
0.6*
0.35*
1.6
0.6*
0.35*
0.9
0.6*
0.3*
0.3
0.6*
0.3*
0.9
Fin Thick.
(m
m)
0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3
Fin Pitch
(m
m)
5 5 5 5 5 5 2 2
No. fins 50 60 130 150 305 175 140 420
No. tubes 100 100 100 100 100 100 100 100
8. Ahmed N. Shmroukh et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 4, ( Part -6) April 2015, pp.66-76
www.ijera.com 73 | P a g e
condensation of refrigerant molecules inside the
adsorbent pores, then its temperature is decreased due
to no more refrigerant adsorbed after 8 minutes.
Water outlet temperature was increased due to
absorbing the heat of adsorption. At the end of the
adsorption process, the pressure inside the adsorption
bed reaches 2.5 bar which is nearly reaches the
refrigerant charging pressure.
Fig. 3: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 25 °C adsorption.
Figures (4) to (6) illustrate the relation between
the measured adsorbent temperature inside the
adsorber and water outlet from the adsorber with
time, in 70 °C, 80 °C and 85 °C desorption modes
after 25 °C adsorption. In all of those experiments
Water outlet temperature was decreased due to
rejecting the heat needed for desorption. The
adsorbent temperature inside the adsorber decreased
in the beginning of the desorption processes, due to
evaporation of refrigerant molecules from the
adsorbent pores, then its temperature is increased due
to no more refrigerant desorbed after 11 minutes in
case of desorption at 70 °C, 6 minutes in case of
desorption at 80 °C, 3 minutes only in case of
desorption at 85 °C. Therfore, when the desorption
temperature increased at the same adsorption
temperature, the desorption time decreased due to
increase the ability of desorbing more refrigerant
from the adsorbent at higher temperatures.
Fig. 4: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 70 °C desorption after 25
°C adsorption.
Fig. 5: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 80 °C desorption
correspondence to 25 °C adsorption case.
Fig. 6: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 85 °C desorption after 25
°C adsorption.
Figure (7) indicates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time in 30 °C
adsorption mode. The adsorbent temperature inside
the adsorber increased in the beginning of the
adsorption processes, due to condensation of
refrigerant molecules inside the adsorbent pores, then
its temperature is decreased due to no more
refrigerant adsorbed after 4 minutes. Water outlet
temperature was increased due to absorbing the heat
of adsorption. At the end of the adsorption process,
the pressure inside the adsorption bed reaches 2.45
bar which is nearly reaches the refrigerant charging
pressure.
Fig. 7: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 30 °C adsorption.
9. Ahmed N. Shmroukh et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 4, ( Part -6) April 2015, pp.66-76
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Figure (8) illustrates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time, in 85
°C desorption mode after 30 °C adsorption. In this
experiment the adsorbent temperature inside the
adsorber decreased in the beginning of the desorption
processes, due to evaporation of refrigerant
molecules from the adsorbent pores, then its
temperature is increased due to no more refrigerant
desorbed after 3 minutes. Water outlet temperature
was decreased due to rejecting the heat needed for
desorption.
Fig. 8: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 85 °C desorption
correspondence to 30 °C adsorption case.
Figure (9) indicates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time in 35 °C
adsorption mode. The adsorbent temperature inside
the adsorber increased in the beginning of the
adsorption processes, due to condensation of
refrigerant molecules inside the adsorbent pores, then
its temperature is decreased due to no more
refrigerant adsorbed after 3 minutes. Water outlet
temperature was increased due to absorbing the heat
of adsorption. At the end of the adsorption process,
the pressure inside the adsorption bed reaches 2.45
bar which is nearly reaches the refrigerant charging
pressure.
Fig. 9: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 35 °C adsorption.
Figure (10) illustrates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time, in 85
°C desorption modes after 35 °C adsorption. In this
experiment the adsorbent temperature inside the
adsorber decreased in the beginning of the desorption
processes, due to evaporation of refrigerant
molecules from the adsorbent pores, then its
temperature is increased due to no more refrigerant
desorbed after 4 minutes. Water outlet temperature
was decreased due to rejecting the heat needed for
desorption.
Fig. 10: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 85 °C desorption after 35
°C adsorption.
Figure (11) indicates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time in 50 °C
adsorption mode. Water outlet temperature was
increased due to absorbing the heat of adsorption.
The adsorbent temperature inside the adsorber
increased in the beginning of the adsorption
processes, due to condensation of refrigerant
molecules inside the adsorbent pores, then its
temperature is decreased due to no more refrigerant
adsorbed. Due to the increase in adsorption
temperature, a small amount of refrigerant adsorbed
quickly. At the end of the adsorption process, the
pressure inside the adsorption bed reaches 2.3 bar
which is nearly reaches the refrigerant charging
pressure.
Fig. 11: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 50 °C adsorption.
Figure (12) illustrates the relation between the
measured adsorbent temperature inside the adsorber
and water outlet from the adsorber with time, in 85
°C desorption modes after 50 °C adsorption. In this
10. Ahmed N. Shmroukh et al. Int. Journal of Engineering Research and Applications www.ijera.com
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experiment the adsorbent temperature inside the
adsorber decreased in the beginning of the desorption
processes, due to evaporation of refrigerant
molecules from the adsorbent pores, then its
temperature is increased due to no more refrigerant
desorbed after 4 minutes. Water outlet temperature
was decreased due to rejecting the heat needed for
desorption.
Fig. 12: Comparison between the measured adsorbent
temperature inside the adsorber and water exit from
the adsorber with time at 85 °C desorption
correspondence to 50 °C adsorption case.
Table (8) illustrates the operation and switching
processes for two complete cycles of a 3-bed
adsorption chiller equipped with activated carbon
powder-R-407c pair, using the optimum adsorption
and desorption times of this pair, which obtained at
25 °C adsorption mode to be 8 minutes and at 85 °C
desorption mode to be 3 minutes. In this case using
three beds is suitable for these values of optimum
time because the adsorption time is more than twice
the desorption time.
Table 8 The operation processes of 3-bed system
with activated carbon powder-R-407c pair
Time
(min)
Bed I Bed II Bed III
0 Desorption --- ---
3 Adsorption Desorption ---
6
Adsorption
Continued
Adsorption ---
8
Adsorption
Continued
Adsorption
Continued
Desorption
11 Desorption
Adsorption
Continued
Adsorption
14 Adsorption Desorption
Adsorption
Continued
17
Adsorption
Continued
Adsorption
Adsorption
Continued
19
Adsorption
Continued
Adsorption
Continued
Desorption
22 Desorption
Adsorption
Continued
Adsorption
Figure 13 illustrates the relation between the
adsorption capacity of the all tested pairs (ACP/R-
134a, ACP/R-407c, ACP/R-507A, ACG/R-507A,
ACG/R-407c and ACG/R-134a) at different
adsorption temperatures. As shown in the figure, the
adsorption capacity decreased with increase the
adsorption temperature. From the measured data the
following results shown in Fig. (13) are obtained.
The maximum adsorption capacity of ACP//R-134a
pair was 0.8352 kg kg-1
at 25 °C and became 0.4343
kg kg-1
at 25 °C for ACP//R-407c pair. While it is
0.3163 kg kg-1
at 25 °C for ACP//R-507A pair. Also,
the results showed that the maximum adsorption
capacity is 0.2006 kg kg-1
at 25 °C for ACG//R-507A
pair, 0.1583 kg kg-1
at 25 °C for ACG//R-407c pair
and 0.4986 kg kg-1
at 25 °C for ACG//R-134a. The
main obtained results for all pairs is that, at
adsorption temperature of 25 °C the maximum
adsorption capacity is found to be 0.8352 kg kg-1 for
activated carbon powder with R-134a and the
minimum adsorption capacity found to be 0.1583 kg
kg-1
for activated carbon granules with R-407c.
While, at adsorption temperature of 50 °C the
maximum adsorption capacity is found to be 0.3207
kg kg-1
for activated carbon powder with R-134a and
the minimum adsorption capacity found to be 0.0609
kg kg-1
for activated carbon granules with R-407c. It
can be indicated from the figure that for the same
refrigerant, the activated carbon powder adsorbent
had higher sorption ability than the granular activated
carbon adsorbent, this is due to the high surface area
of the activated carbon powder adsorbent. Also, the
adsorption capacity of all pairs is decreased by
increasing the adsorption temperature, due to
decreasing the sorption ability by increasing the
adsorption temperature.
Fig. 13: Adsorption capacity of the whole six
adsorption pairs with respect to the adsorption
temperature.
IV. CONCLUSIONS
This study is experimentally targeting to
develop effective in heat and mass transfer processes
for the adsorbate to obtain applicable adsorption
capacity data. This is done by using fin and tube heat
exchanger and the adosrbate is sticked over its
surface and located at the core of the adsorber. This is
to estimate experimentally the maximum adsorption
11. Ahmed N. Shmroukh et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN : 2248-9622, Vol. 5, Issue 4, ( Part -6) April 2015, pp.66-76
www.ijera.com 76 | P a g e
capacity for six different adsorption refrigeration
working pairs. The pairs are ACP/R-134a, ACP/R-
407c, ACP/R-507A, ACG/R-507A, ACG/R-407c and
ACG/R-134a, at different adsorption temperatures of
25, 30, 35 and 50 °C. The following is concluded
from the results:
At adsorption temperature of 25 °C the maximum
adsorption capacity is found to be 0.8352 kg kg-1
for
activated carbon powder with R-134a and the
minimum adsorption capacity found to be 0.1583 kg
kg-1
for activated carbon granules with R-407c.
While, at adsorption temperature of 50 °C the
maximum adsorption capacity is found to be 0.3207
kg kg-1
for activated carbon powder with R-134a and
the minimum adsorption capacity found to be 0.0609
kg kg-1
for activated carbon granules with R-407c.
As the adsorption temperature increased, the
adsorption rate decreased.
For the same refrigerant, the activated carbon
powder adsorbent had higher sorption ability than the
granular activated carbon adsorbent, this is due to its
high surface area.
The ACP//R-134a pair is highly recommended to
be used as adsorption refrigeration working pair
because of its higher maximum adsorption capacity
than the other tested pairs, to produce an adsorption
refrigeration system that is compact, efficient,
reliable and long life.
Activated carbon granules/R-134a and activated
carbon powder/R-134a 5 kW chillers are the most
compact chiller components among the whole tested
pairs, as their shell and tube condensers dimension
are 0.83m for tubes length and 0.43m shell diameter,
their shell and tube evaporators dimension are 0.87m
for tubes length and 0.32m shell diameter and their
fin and tube adsorbers dimension are
0.6m*0.35m*0.26m for activated carbon granules/R-
134a chiller and 6m* 0.35m*0.31m for activated
carbon powder/R-134a chiller.
ACKNOWLEDGEMENT
The first author would like to acknowledge
Ministry of Higher Education (MoHE) of Egypt for
providing a scholarship to conduct this study as well
as the Egypt Japan University of Science and
Technology (E-JUST) for offering the facility and
tools needed to conduct this work.
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