Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water whe...Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.展开更多
With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted great attention of many researchers recently. In this study, non-azeotropic mixtures composed o...With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted great attention of many researchers recently. In this study, non-azeotropic mixtures composed of HFOs (HFO-1234yf, HFO-1234ze(z), HFO-1234ze(e) and HFO-1234zf) are developed to substitute for HFC-134a and CFC-114 in air-conditioning and high-temperature heat pump systems, respectively. The cycle performances were evaluated by an improved theoretical cy-cle evaluation methodology. The results showed that all the mixtures proposed herein were favorable refrigerants with excel-lent thermodynamic cycle performances. M1A presented lower discharge temperature and pressure ratio and higher COPc than that of HFC-134a. The volumetric cooling capacity was similar to HFC-134a. It can be served as a good environmentally friendly alternative to replace HFC-134a. M3H delivered similar discharge temperature as CFC-114 did. And the COPh was 3% higher. It exhibits excellent cycle performance in high-temperature heat pump and is a promising refrigerant to substitute for CFC-114. And the gliding temperature differences enable them to exhibit better coefficient of performance by matching the sink/source temperature in practice. Because the toxicity, flammability and other properties are not investigated in detail, ex-tensive toxicity and flammability testing needs to be conducted before they are used in a particular application.展开更多
为解决低温余热资源过剩与高温用热需求紧缺之间的矛盾,设计了一套基于准二级压缩的高温热泵机组,理论分析循环流程并进行优化设计,采用闪蒸器与回热器组合提高机组性能,开展了机组的性能实验,以制热量、制热COP、[火用]效率、冷凝压力...为解决低温余热资源过剩与高温用热需求紧缺之间的矛盾,设计了一套基于准二级压缩的高温热泵机组,理论分析循环流程并进行优化设计,采用闪蒸器与回热器组合提高机组性能,开展了机组的性能实验,以制热量、制热COP、[火用]效率、冷凝压力、排气温度为性能指标,在冷凝器出水温度为85~120℃,蒸发器进水温度为50、60、70℃工况下,对机组性能进行分析。实测机组性能与理论计算结果吻合,蒸发器进水温度为49.8℃,冷凝器出水温度为118.1℃,机组制热量可达916.3 k W,制热COP为2.51,[火用]效率为46.3%,机组冷凝压力为1.8 MPa,排气温度为137℃,符合机组安全运行的要求。展开更多
为解决中深层地源热泵系统(GSHP)地温衰减的问题,以邯郸市某民用节能建筑为研究对象,基于TRNSYS建立一种PV/T耦合中深层地源热泵系统(PV/T-GSHP),并与GSHP系统对比,模拟分析运行20 a PV/T-GSHP系统运行特性。探究PV/T组件的相关参数对...为解决中深层地源热泵系统(GSHP)地温衰减的问题,以邯郸市某民用节能建筑为研究对象,基于TRNSYS建立一种PV/T耦合中深层地源热泵系统(PV/T-GSHP),并与GSHP系统对比,模拟分析运行20 a PV/T-GSHP系统运行特性。探究PV/T组件的相关参数对土壤平均温度的影响。最后,将PV/T-GSHP系统与其他系统进行能耗对比。研究结果表明:与GSHP系统相比,PV/T-GSHP系统机组COP从6.44提高到6.81,但由于增加了泵功,系统COP降到2.38,但考虑发电量,平均每年可获得10015.831元收益;相似结构建筑PV/T组件屋顶铺设占比越大,集热泵流量越小,土壤平均温升越快;不考虑发电量时,PV/T-GSHP系统比燃气锅炉系统能耗高8.46%,与燃煤锅炉和电锅炉系统相比,分别可节约11.04%和48.55%的能耗;综合发电量时,20 a实际获得的发电量收益折合成燃煤量为210.05 t。展开更多
文章提出了一种利用高温热泵回收冷却水余热制备中、高温热水的方案。通过建立简化的热力学模型,分析冷、热源温度对热泵单位制热量、单位压缩功及COP(Coefficient of Performance,能效比)值的影响。并从经济节能和环境保护两个方面进...文章提出了一种利用高温热泵回收冷却水余热制备中、高温热水的方案。通过建立简化的热力学模型,分析冷、热源温度对热泵单位制热量、单位压缩功及COP(Coefficient of Performance,能效比)值的影响。并从经济节能和环境保护两个方面进行了效益分析,结果表明:与传统的蒸汽加热制备热水相比,高温热泵回收冷却水余热制备中、高温热水的方案具有经济效益和环境效益,更符合节能减排要求。展开更多
Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quali...Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.展开更多
基金Supported by Major State Basic Research Development Program of China ("973" Program, No. 2009CB219907)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0936)
文摘Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained.
基金supported by the National Natural Science Foundation of China (Grant No. 50976079)Science and Technology Support Key Project of Tianjin (Grant No. 10ZCKFGX01700)
文摘With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted great attention of many researchers recently. In this study, non-azeotropic mixtures composed of HFOs (HFO-1234yf, HFO-1234ze(z), HFO-1234ze(e) and HFO-1234zf) are developed to substitute for HFC-134a and CFC-114 in air-conditioning and high-temperature heat pump systems, respectively. The cycle performances were evaluated by an improved theoretical cy-cle evaluation methodology. The results showed that all the mixtures proposed herein were favorable refrigerants with excel-lent thermodynamic cycle performances. M1A presented lower discharge temperature and pressure ratio and higher COPc than that of HFC-134a. The volumetric cooling capacity was similar to HFC-134a. It can be served as a good environmentally friendly alternative to replace HFC-134a. M3H delivered similar discharge temperature as CFC-114 did. And the COPh was 3% higher. It exhibits excellent cycle performance in high-temperature heat pump and is a promising refrigerant to substitute for CFC-114. And the gliding temperature differences enable them to exhibit better coefficient of performance by matching the sink/source temperature in practice. Because the toxicity, flammability and other properties are not investigated in detail, ex-tensive toxicity and flammability testing needs to be conducted before they are used in a particular application.
文摘为解决低温余热资源过剩与高温用热需求紧缺之间的矛盾,设计了一套基于准二级压缩的高温热泵机组,理论分析循环流程并进行优化设计,采用闪蒸器与回热器组合提高机组性能,开展了机组的性能实验,以制热量、制热COP、[火用]效率、冷凝压力、排气温度为性能指标,在冷凝器出水温度为85~120℃,蒸发器进水温度为50、60、70℃工况下,对机组性能进行分析。实测机组性能与理论计算结果吻合,蒸发器进水温度为49.8℃,冷凝器出水温度为118.1℃,机组制热量可达916.3 k W,制热COP为2.51,[火用]效率为46.3%,机组冷凝压力为1.8 MPa,排气温度为137℃,符合机组安全运行的要求。
文摘为解决中深层地源热泵系统(GSHP)地温衰减的问题,以邯郸市某民用节能建筑为研究对象,基于TRNSYS建立一种PV/T耦合中深层地源热泵系统(PV/T-GSHP),并与GSHP系统对比,模拟分析运行20 a PV/T-GSHP系统运行特性。探究PV/T组件的相关参数对土壤平均温度的影响。最后,将PV/T-GSHP系统与其他系统进行能耗对比。研究结果表明:与GSHP系统相比,PV/T-GSHP系统机组COP从6.44提高到6.81,但由于增加了泵功,系统COP降到2.38,但考虑发电量,平均每年可获得10015.831元收益;相似结构建筑PV/T组件屋顶铺设占比越大,集热泵流量越小,土壤平均温升越快;不考虑发电量时,PV/T-GSHP系统比燃气锅炉系统能耗高8.46%,与燃煤锅炉和电锅炉系统相比,分别可节约11.04%和48.55%的能耗;综合发电量时,20 a实际获得的发电量收益折合成燃煤量为210.05 t。
文摘文章提出了一种利用高温热泵回收冷却水余热制备中、高温热水的方案。通过建立简化的热力学模型,分析冷、热源温度对热泵单位制热量、单位压缩功及COP(Coefficient of Performance,能效比)值的影响。并从经济节能和环境保护两个方面进行了效益分析,结果表明:与传统的蒸汽加热制备热水相比,高温热泵回收冷却水余热制备中、高温热水的方案具有经济效益和环境效益,更符合节能减排要求。
基金supported by the National Key R&D Program of China(Grant No. 2017YFB0305702)。
文摘Two kinds of silver based medium temperature brazing filler metals(45AgCuZnSn and 60AgCuSn) were selected to braze and seal brass flange pipe and copper pipe by high frequency heating brazing. In this paper, the quality of the braze was evaluated by immersion ultrasound, and the microstructure of the brazed joint was observed by SEM and EDS. The experimental results show that the high frequency heating brazing can quickly achieve the device sealing;through the ultrasonic flaw detection image calculation, the brazed bonding rate obtained by 60AgCuSn brazing is 87%, and by 45AgCuZnSn brazing is 71%;the cross-sectional area of the brazed joint obtained by two kinds of silver based medium temperature brazing filler metals is observed, the brazed joint obtained by 45AgCuZnSn brazing has defects visual, and a large amount of Zn element gathered in the defects, there is no obvious porosity in the brazed joint by 60AgCuSn brazing,and the bonding layer is dense and coherent. Through the contrast test, the choice of 60AgCuSn alloy brazing can meet the needs of high frequency brazing of brass flange pipe and copper pipe.
