In this paper,we studied theoretically and numerically heated losses of a flat solar collector to model the solar water heating system for the Kazakhstan climate condition.For different climatic zones with a growing c...In this paper,we studied theoretically and numerically heated losses of a flat solar collector to model the solar water heating system for the Kazakhstan climate condition.For different climatic zones with a growing cost for energy or lack of central heating systems,promising is to find ways to improve the energy efficiency of the solar system.The mathematical model(based on ordinary differential equation)simulated the solar system work process under different conditions.To bridge the modeling and real values results,we studied the important physical parameters such as loss coefficient,Nu,Ra,and Pr values.They impacted the efficiency of flat solar collectors and heat losses of the system.The developed mathematical models,the design and composition of the software and hardware complex,and automated control and monitoring systems allow solar hot water heating systems to increase the energy efficiency of life support systems and heat supply of buildings by reducing energy consumption for heat supply.The simulation result showed that during the daytime,the temperature of water in the collector is 70°C;the storage of heated water since heated water is cooled at night.We defined that a work period of the system can be extended with high efficiency(April-October)for Almaty region.展开更多
Nanofluids are a potential alternative to significantly improving the performance of heat transfer applications. In this work, a numerical analysis to examine the eff ect of dispersing copper(Cu), copper oxide(CuO), a...Nanofluids are a potential alternative to significantly improving the performance of heat transfer applications. In this work, a numerical analysis to examine the eff ect of dispersing copper(Cu), copper oxide(CuO), and aluminum(Al2O3) nanoparticles in pure water on the performance of a flat plate solar collector(FPSC) and a numerical model was proposed. The influence of the nanofluid type on the thermal efficiency was critically investigated and discussed. The eff ect of the mass flow rate on the performance was also analyzed and discussed. Based on correlations of the thermophysical properties of nanofluids, a sensitivity analysis was used to analyze the impact of the nanoparticles on the base fluid. The results indicate that the performance of the FPSC with Cu/water nanofluid was better than that of FPSCs using CuO/water or Al2O3/water nanofluids. When the mass flow rate of the nanofluids was 8.0 L/min, the efficiency of the FPSC was much greater than those at the flow rates of 5.0 L/min and 2.0 L/min. Mean enhancements in thermal efficiency of 4.44%, 4.27%, and 4.21% were observed when 2.0 L/min was applied using Cu/water, Cu O/water, and Al2O3/water nanofluids, respectively. Improvements in thermal efficiency of 2.76%, 2.53%, and 2.47% occurred when 8.0 L/min was applied.展开更多
Exergy analysis is a critical aspect of Energy Engineering that can not be overstretched.The need for constant study in this area is very crucial due to it evolving nature.This study involved the analysis of exergy of...Exergy analysis is a critical aspect of Energy Engineering that can not be overstretched.The need for constant study in this area is very crucial due to it evolving nature.This study involved the analysis of exergy of an Experimental Domestic Scale Solar Water Heating System situated in Owerri,Imo State,Nigeria.There were couples of literature reviews done in relation to the study.It was aimed at analyzing the efficiency of solar water heating system.Basic materials involved in this study are solar radiation collector panel,storage tank,pump,heat exchanger,piping unit and heat transfer fluid.From the results,it recorded that collector outlet temperature is a function of solar radiation and time.Maximum Collector Efficiency occurred at 1 p.m.of the set up location time.It was further revealed that performance of the flat plate solar water heater(SWH)obtained maximum of 97%and minimum of 38%efficiencies at 1 p.m.and 5 p.m.respectively.The highest exergy efficiency gotten was 60%at 1 p.m.and the lowest was 1.9%at 9 a.m.Hence,exergy analysis is a useful method for optimizing performance of a flat plate solar water heating system due to it proportionality to basic quantities in solar studies.展开更多
基金Thisworkwas supported by the Ministry of Education and Science of theRepublic of Kazakhstan BR10965172。
文摘In this paper,we studied theoretically and numerically heated losses of a flat solar collector to model the solar water heating system for the Kazakhstan climate condition.For different climatic zones with a growing cost for energy or lack of central heating systems,promising is to find ways to improve the energy efficiency of the solar system.The mathematical model(based on ordinary differential equation)simulated the solar system work process under different conditions.To bridge the modeling and real values results,we studied the important physical parameters such as loss coefficient,Nu,Ra,and Pr values.They impacted the efficiency of flat solar collectors and heat losses of the system.The developed mathematical models,the design and composition of the software and hardware complex,and automated control and monitoring systems allow solar hot water heating systems to increase the energy efficiency of life support systems and heat supply of buildings by reducing energy consumption for heat supply.The simulation result showed that during the daytime,the temperature of water in the collector is 70°C;the storage of heated water since heated water is cooled at night.We defined that a work period of the system can be extended with high efficiency(April-October)for Almaty region.
文摘Nanofluids are a potential alternative to significantly improving the performance of heat transfer applications. In this work, a numerical analysis to examine the eff ect of dispersing copper(Cu), copper oxide(CuO), and aluminum(Al2O3) nanoparticles in pure water on the performance of a flat plate solar collector(FPSC) and a numerical model was proposed. The influence of the nanofluid type on the thermal efficiency was critically investigated and discussed. The eff ect of the mass flow rate on the performance was also analyzed and discussed. Based on correlations of the thermophysical properties of nanofluids, a sensitivity analysis was used to analyze the impact of the nanoparticles on the base fluid. The results indicate that the performance of the FPSC with Cu/water nanofluid was better than that of FPSCs using CuO/water or Al2O3/water nanofluids. When the mass flow rate of the nanofluids was 8.0 L/min, the efficiency of the FPSC was much greater than those at the flow rates of 5.0 L/min and 2.0 L/min. Mean enhancements in thermal efficiency of 4.44%, 4.27%, and 4.21% were observed when 2.0 L/min was applied using Cu/water, Cu O/water, and Al2O3/water nanofluids, respectively. Improvements in thermal efficiency of 2.76%, 2.53%, and 2.47% occurred when 8.0 L/min was applied.
文摘Exergy analysis is a critical aspect of Energy Engineering that can not be overstretched.The need for constant study in this area is very crucial due to it evolving nature.This study involved the analysis of exergy of an Experimental Domestic Scale Solar Water Heating System situated in Owerri,Imo State,Nigeria.There were couples of literature reviews done in relation to the study.It was aimed at analyzing the efficiency of solar water heating system.Basic materials involved in this study are solar radiation collector panel,storage tank,pump,heat exchanger,piping unit and heat transfer fluid.From the results,it recorded that collector outlet temperature is a function of solar radiation and time.Maximum Collector Efficiency occurred at 1 p.m.of the set up location time.It was further revealed that performance of the flat plate solar water heater(SWH)obtained maximum of 97%and minimum of 38%efficiencies at 1 p.m.and 5 p.m.respectively.The highest exergy efficiency gotten was 60%at 1 p.m.and the lowest was 1.9%at 9 a.m.Hence,exergy analysis is a useful method for optimizing performance of a flat plate solar water heating system due to it proportionality to basic quantities in solar studies.
