The continuous increase in the level of greenhouse gas emissions and the depletion of fossil fuel... more The continuous increase in the level of greenhouse gas emissions and the depletion of fossil fuels are identified, as the major driving forces behind efforts to effectively utilize different sources of renewable energy. Solar energy considered one of the most prospective sources of this energy. This review paper mainly focuses on the majority of heat-transfer enhancement techniques between the phase-change material (PCM) and the heat-transfer fluid (HTF) based on the application of fins embedded in the PCM. This study also investigated the geometrical dimensions, dimensionless numbers, and fin location through numerical and experimental works conducted to assess the influences of these parameters on the thermal performance of PCM-latent heat thermal energy storage (LHTES) containers. The best enhancement is achieved using the longitudinal finned configurations because of its easy design and fabrication, especially along circumference of the cylindrical PCM containers. The circular-finned tube was also more effective than the pinned-tube for different shell and tube. PCMs based on heat sinks with internal pin fins were widely used for the thermal management of various pieces of electronic products. The heat enhancement factor was effectively dependent on increasing the numbers and dimensions of these fins. Further researches still require to explore the possible geometrical designs of fins and their key findings, which have more effect on the thermal performance of the finned-LHTES system.
... study of Malaysia. WSEAS Transactions on Environment and Development 2008.4(4) 373-378 [14] A... more ... study of Malaysia. WSEAS Transactions on Environment and Development 2008.4(4) 373-378 [14] AW Azhari, A. Zaharim, K. Sopian, AH Ibrahim. Cloud based models in determination of solar radiations. Proceedings of the ...
ABSTRACT Performance of the absorption cooling system is still a challenge due to the coefficient... more ABSTRACT Performance of the absorption cooling system is still a challenge due to the coefficient of performance (COP) that is generally poor when compared with the conventional vapor compression cycle. High solar radiation in hot climates is usually associated with high ambient temperature and consequently peak cooling demand. Absorption cooling cycles can be powered by solar but the performance is limited by heat source temperature (solar collector) and high ambient temperature that can affect the condensation process. Efficiency enhancement of the system components is essential to increase the COP of the system. A modification in the combined absorption–ejector cooling system is adopted. Adding a removable flash tank between the condenser and evaporator could improve entrainment ratio of the ejector, along with improving the cooling effect inside the evaporator. A computer simulation program is developed to evaluate the performance of the modified combined cycle using aqua-ammonia (NH3–H2O) refrigerant. The performance of the proposed combined cooling cycle is compared with basic absorption, and combined absorption–ejector cooling cycles. Results showed a significant improvement in the COP of the modified cycle at different operating conditions. Cooling effect and capacity of the evaporator is enhanced due to the reduction of flash gas delivered to the evaporator. Furthermore, the flash tank optimized the ejector entertainment ratio and consequently increasing the condenser pressure. This optimization will enable the system to perform well in hot climates where the condenser efficiency is limited by ambient temperature.
The objective of this paper is to provide a literature review on solar-driven ejector refrigerati... more The objective of this paper is to provide a literature review on solar-driven ejector refrigeration systems and to give useful guidelines regarding background and operating principles of ejector. The development history and recent progress in solar-driven ejector refrigeration systems are reported and categorized. It shows that solar-driven ejector refrigeration technologies are not only can serve the needs for cooling requirements such as air-conditioning and ice-making and medical or food preservation in remote areas, but ...
Abstract:-Solar hydrogen system is a unique power system that can meet the power requirement for ... more Abstract:-Solar hydrogen system is a unique power system that can meet the power requirement for the energy future demand, in such a system the hydrogen used to be the energy carrier which can produced through the electrolyzers with the assist of the power ...
Proceedings of the 3rd Wseas Int. Conf. On Renewable Energy Sources, 2009
Abstract:-The experimental investigation of the performance of a solar absorption refrigeration s... more Abstract:-The experimental investigation of the performance of a solar absorption refrigeration system is described. The influence of generator, evaporator and condenser temperatures on the system performance is studied using evacuated tube solar collectors and ammonia-water as working fluid. It was seen that if higher cooling capacity and also lower evaporator temperature are desired from the system, the generator temperature should be increased considerably. In general, a solar absorption system can work only if ...
Abstract-Absorption refrigeration systems powered by solar energy increasingly attract research i... more Abstract-Absorption refrigeration systems powered by solar energy increasingly attract research interests in the last years. In this study, thermodynamic analyses for different working fluid pairs are performed. A computer simulation model has been developed to predict the performance of solar absorption refrigeration system using different working fluid. The model is based on detailed mass and energy balance and heat and mass transfer for the cycle component. Detailed thermodynamic properties for ammonia-water, ammonia- ...
Abstract: A procedure is presented for assessing the economic viability of a solar cooling system... more Abstract: A procedure is presented for assessing the economic viability of a solar cooling system in terms of the life cycle savings function. The optimization is carried out for a solar cooling system that has been designed for Malaysia and similar tropical regions using evacuated tube solar collectors and ammonia-water absorption unit. The life cycle savings is expressed in a generalized form in terms of two economic parameters, P1 and P2, which relate all life cycle cost considerations to the first year fuel cost or the initial solar system ...
Abstract: This study presents an economic analysis on a solar based stand-alone PV system to prov... more Abstract: This study presents an economic analysis on a solar based stand-alone PV system to provide the required electricity for a typical home. The area under interest selected is the solar energy park located at University Kebangsaan Malaysia in Bangi, Malaysia. The stand-alone PV system consists of a Solar panel, DC-DC Converter, Maximum Power Point Tracker, DC/AC Inverter, and Battery. The life cycle cost (LCC) analysis is used to assess the economic viability of the system. The economic analysis results of the study encouraged ...
A numerical investigation of transient, two-dimensional natural convection in horizontal isotherm... more A numerical investigation of transient, two-dimensional natural convection in horizontal isothermal cylindrical annuli is performed to investigate the Prandtl number and diameter ratio effect on flow and heat transfer characteristics. The finite difference method is used to solve the governing equations, in which buoyancy is modeled via the Boussinesq approximation. Both vorticity and energy equations are solved using alternating direction implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. Solutions for laminar case are obtained up to Grashof number of 10 5 as well as three different diameter ratios, namely 1.2, 1.5, and 2.0 and the Prandtl number varies from 0.7 to 10 are considered. The computed flow patterns and temperature fields are shown by means of streamlines and isotherms, respectively, and the average heat transfer coefficients are also presented. The numerical results are summarized by Nusselt number vs. Grashof number correlations with the Prandtl number and diameter ratio as a parameter. The results of the parametric study show that the diameter ratio and Grashof number have a profound influence on the temperature and flow field and they are almost independent of a low Prandtl number fluid. The average Nusselt number increases by 25% at large of diameter ratio and Prandtl number. Good agreement with earlier available data is obtained.
The continuous increase in the level of greenhouse gas emissions and the depletion of fossil fuel... more The continuous increase in the level of greenhouse gas emissions and the depletion of fossil fuels are identified, as the major driving forces behind efforts to effectively utilize different sources of renewable energy. Solar energy considered one of the most prospective sources of this energy. This review paper mainly focuses on the majority of heat-transfer enhancement techniques between the phase-change material (PCM) and the heat-transfer fluid (HTF) based on the application of fins embedded in the PCM. This study also investigated the geometrical dimensions, dimensionless numbers, and fin location through numerical and experimental works conducted to assess the influences of these parameters on the thermal performance of PCM-latent heat thermal energy storage (LHTES) containers. The best enhancement is achieved using the longitudinal finned configurations because of its easy design and fabrication, especially along circumference of the cylindrical PCM containers. The circular-finned tube was also more effective than the pinned-tube for different shell and tube. PCMs based on heat sinks with internal pin fins were widely used for the thermal management of various pieces of electronic products. The heat enhancement factor was effectively dependent on increasing the numbers and dimensions of these fins. Further researches still require to explore the possible geometrical designs of fins and their key findings, which have more effect on the thermal performance of the finned-LHTES system.
... study of Malaysia. WSEAS Transactions on Environment and Development 2008.4(4) 373-378 [14] A... more ... study of Malaysia. WSEAS Transactions on Environment and Development 2008.4(4) 373-378 [14] AW Azhari, A. Zaharim, K. Sopian, AH Ibrahim. Cloud based models in determination of solar radiations. Proceedings of the ...
ABSTRACT Performance of the absorption cooling system is still a challenge due to the coefficient... more ABSTRACT Performance of the absorption cooling system is still a challenge due to the coefficient of performance (COP) that is generally poor when compared with the conventional vapor compression cycle. High solar radiation in hot climates is usually associated with high ambient temperature and consequently peak cooling demand. Absorption cooling cycles can be powered by solar but the performance is limited by heat source temperature (solar collector) and high ambient temperature that can affect the condensation process. Efficiency enhancement of the system components is essential to increase the COP of the system. A modification in the combined absorption–ejector cooling system is adopted. Adding a removable flash tank between the condenser and evaporator could improve entrainment ratio of the ejector, along with improving the cooling effect inside the evaporator. A computer simulation program is developed to evaluate the performance of the modified combined cycle using aqua-ammonia (NH3–H2O) refrigerant. The performance of the proposed combined cooling cycle is compared with basic absorption, and combined absorption–ejector cooling cycles. Results showed a significant improvement in the COP of the modified cycle at different operating conditions. Cooling effect and capacity of the evaporator is enhanced due to the reduction of flash gas delivered to the evaporator. Furthermore, the flash tank optimized the ejector entertainment ratio and consequently increasing the condenser pressure. This optimization will enable the system to perform well in hot climates where the condenser efficiency is limited by ambient temperature.
The objective of this paper is to provide a literature review on solar-driven ejector refrigerati... more The objective of this paper is to provide a literature review on solar-driven ejector refrigeration systems and to give useful guidelines regarding background and operating principles of ejector. The development history and recent progress in solar-driven ejector refrigeration systems are reported and categorized. It shows that solar-driven ejector refrigeration technologies are not only can serve the needs for cooling requirements such as air-conditioning and ice-making and medical or food preservation in remote areas, but ...
Abstract:-Solar hydrogen system is a unique power system that can meet the power requirement for ... more Abstract:-Solar hydrogen system is a unique power system that can meet the power requirement for the energy future demand, in such a system the hydrogen used to be the energy carrier which can produced through the electrolyzers with the assist of the power ...
Proceedings of the 3rd Wseas Int. Conf. On Renewable Energy Sources, 2009
Abstract:-The experimental investigation of the performance of a solar absorption refrigeration s... more Abstract:-The experimental investigation of the performance of a solar absorption refrigeration system is described. The influence of generator, evaporator and condenser temperatures on the system performance is studied using evacuated tube solar collectors and ammonia-water as working fluid. It was seen that if higher cooling capacity and also lower evaporator temperature are desired from the system, the generator temperature should be increased considerably. In general, a solar absorption system can work only if ...
Abstract-Absorption refrigeration systems powered by solar energy increasingly attract research i... more Abstract-Absorption refrigeration systems powered by solar energy increasingly attract research interests in the last years. In this study, thermodynamic analyses for different working fluid pairs are performed. A computer simulation model has been developed to predict the performance of solar absorption refrigeration system using different working fluid. The model is based on detailed mass and energy balance and heat and mass transfer for the cycle component. Detailed thermodynamic properties for ammonia-water, ammonia- ...
Abstract: A procedure is presented for assessing the economic viability of a solar cooling system... more Abstract: A procedure is presented for assessing the economic viability of a solar cooling system in terms of the life cycle savings function. The optimization is carried out for a solar cooling system that has been designed for Malaysia and similar tropical regions using evacuated tube solar collectors and ammonia-water absorption unit. The life cycle savings is expressed in a generalized form in terms of two economic parameters, P1 and P2, which relate all life cycle cost considerations to the first year fuel cost or the initial solar system ...
Abstract: This study presents an economic analysis on a solar based stand-alone PV system to prov... more Abstract: This study presents an economic analysis on a solar based stand-alone PV system to provide the required electricity for a typical home. The area under interest selected is the solar energy park located at University Kebangsaan Malaysia in Bangi, Malaysia. The stand-alone PV system consists of a Solar panel, DC-DC Converter, Maximum Power Point Tracker, DC/AC Inverter, and Battery. The life cycle cost (LCC) analysis is used to assess the economic viability of the system. The economic analysis results of the study encouraged ...
A numerical investigation of transient, two-dimensional natural convection in horizontal isotherm... more A numerical investigation of transient, two-dimensional natural convection in horizontal isothermal cylindrical annuli is performed to investigate the Prandtl number and diameter ratio effect on flow and heat transfer characteristics. The finite difference method is used to solve the governing equations, in which buoyancy is modeled via the Boussinesq approximation. Both vorticity and energy equations are solved using alternating direction implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. Solutions for laminar case are obtained up to Grashof number of 10 5 as well as three different diameter ratios, namely 1.2, 1.5, and 2.0 and the Prandtl number varies from 0.7 to 10 are considered. The computed flow patterns and temperature fields are shown by means of streamlines and isotherms, respectively, and the average heat transfer coefficients are also presented. The numerical results are summarized by Nusselt number vs. Grashof number correlations with the Prandtl number and diameter ratio as a parameter. The results of the parametric study show that the diameter ratio and Grashof number have a profound influence on the temperature and flow field and they are almost independent of a low Prandtl number fluid. The average Nusselt number increases by 25% at large of diameter ratio and Prandtl number. Good agreement with earlier available data is obtained.
Uploads
Papers by Jasim Abdulateef