The effect of the circulation fan installed in fresh food compartment on energy consumption of natural convective refrigerator/freezers (RFs) was experimentally studied. Five different RF models with different cycles ...The effect of the circulation fan installed in fresh food compartment on energy consumption of natural convective refrigerator/freezers (RFs) was experimentally studied. Five different RF models with different cycles were tested. The experimental results showed that the energy consumption of the single-loop cycle RF increased by 2.4%~3.8%, that of the bypass two-circuit cycle RF decreased by 1.0%, and that of the two-circuit cycle RF with its evaporators in parallel when the geometry parameters of refrigeration system and the refrigerant charge were not changed after the circulation fan was installed decreased by 3.3%. When the optimization on the refrigerant charge and the evaporator was carried out, the energy consumption of the single-loop cycle RF , the bypass two-circuit cycle RF and the two-circuit cycle RF with its evaporators in parallel, decreased by 1.0%~6.4%, 3.25% and 3.26% respectively. The present conclusions will provide a guideline to the optimum design for the RF with the circulation fan.展开更多
Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely us...Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD （Computational Fluid Dynamics） soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.展开更多
Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature a...Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.展开更多
文摘The effect of the circulation fan installed in fresh food compartment on energy consumption of natural convective refrigerator/freezers (RFs) was experimentally studied. Five different RF models with different cycles were tested. The experimental results showed that the energy consumption of the single-loop cycle RF increased by 2.4%~3.8%, that of the bypass two-circuit cycle RF decreased by 1.0%, and that of the two-circuit cycle RF with its evaporators in parallel when the geometry parameters of refrigeration system and the refrigerant charge were not changed after the circulation fan was installed decreased by 3.3%. When the optimization on the refrigerant charge and the evaporator was carried out, the energy consumption of the single-loop cycle RF , the bypass two-circuit cycle RF and the two-circuit cycle RF with its evaporators in parallel, decreased by 1.0%~6.4%, 3.25% and 3.26% respectively. The present conclusions will provide a guideline to the optimum design for the RF with the circulation fan.
文摘Like in other sectors of activity, the sustainability in refrigeration systems is a mandatory goal to achieve, namely at house holdings, bars and restaurants, where small-scale refrigerators and freezers are widely used. The aim of this work is to demonstrate experimentally, trough measurements carried out in these equipments, the improvement that can be achieved if several modifications are implemented in traditional household refrigeration systems. In addition, it was also simulated and analysed experimentally a slightly different equipment, a refrigeration system used for draught beverages. Both systems work on a single vapour compression refrigeration with R-134a as working fluid. In the end, by implemented the modifications tested in the virtual model, it was possible to improve their thermal behaviour, a decrease in electrical energy consumption, as well as, the associated CO2 emissions reduction can be attained. In this project, the CFD （Computational Fluid Dynamics） soffware--ANSYS Fluent was used to simulate the ambient temperature and velocity fields inside the refrigerator and in that way to validate the measured results.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.41877370 and 42077190)the China Postdoctoral Science Foundation(No.2021M691229)+2 种基金the fund of Creative Research Groups of NSFC(No.42121004)the Science and Technology Planning Project of Guangdong Province of China(No.2019B121202002)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N263).
文摘Smog chambers are the effective tools for studying formation mechanisms of air pollution.Simulations by traditional smog chambers differ to a large extent from real atmospheric conditions,including light,temperature and atmospheric composition.However,the existing parameters for mechanism interpretation are derived from the traditional smog chambers.To address the gap between the traditional laboratory simulations and the photochemistry in the real atmosphere,a vehicle-mounted indoor-outdoor dual-smog chamber(JNUVMDSC)was developed,which can be quickly transferred to the desired sites to simulate quasi-realistic atmosphere simultaneously in both chambers using“local air”.Multiple key parameters of the smog chamber were characterized in the study,demonstrating that JNUVMDSC meets the requirements of general atmospheric chemistry simulation studies.Additionally,the preliminary results for the photochemical simulations of quasi-realistic atmospheres in Pearl River Delta region and Nanling Mountains are consistent with literature reports on the photochemistry in this region.JNU-VMDSC provides a convenient and reliable experimental device and means to study the mechanism of atmospheric photochemical reactions to obtain near-real results,and will make a great contribution to the control of composite air pollution.
