Emissions reduction potential from electric heat pumps in California homes

Electric heat pumps offer a promising opportunity to help achieve deep decarbonization of the building sector. However, since electric generators serve load in real time with varying emissions, comparing the emissions impact of heat pumps to their natural gas heating alternatives requires considering time of use. We analyze the temporal load shapes of heat pump water heaters and air-source heat pumps in the context of temporal grid-level emissions data. We find that switching from natural gas to electricity could reduce the annual emissions of a California household by 50–70% and 46–54% for water and space heating, respectively. These findings support the adoption of electric heat pumps as a strategy for deep decarbonization.     

PR方程结合vdW混合法则推算二元及三元HFC/HC混合工质

以PR方程结合vdW混合法则,利用建立的二元相互作用系数kij差值关联模型,对11组二元HFC/HC混合工质及5组三元HFC/HC混合工质（HFC32 / HFC125 / HFC134a,HC290 / HC600a / HFC32,HFC125 / HFC143a / HFC134a,HFC32 / HC290 / HFC227ea,HFC32 / HFC125 / HC290）气液相平衡性质进行了推算,并与文献实验数据比较,对压力计算的平均相对偏差分别为2.225%、8.317%、1.433%、0.403%、1.71%,对气相组分计算的平均绝对偏差分别为0.0086、0.0132、0.0054、0.0071、0.0089。结果表明该方法可用于推算二元及三元HFC/HC混合工质气液相平衡性质。     

HFC-134a生产过程氟化氢回收利用方法

简要综述了HFC-134a生产过程中氟化氢的回收利用方法。分别介绍了吸附法、硫酸洗涤法、氢氟酸洗涤法等氟化氢直接回收利用工艺和氟化氢经过水吸收后制成氢氟酸后制取氟化钙、氟化镁、氟硅酸钾等衍生物盐类实现对氟化氢的再利用方法。HFC-134a生产过程中浪费的氟化氢得到有效地回收和利用,对氟资源的综合利用和环境保护具有积极意义。     

一种同时生产1，1，1，2-四氟乙烷和二氟甲烷的方法

一种同时生产1,1,1,2-四氟乙烷（HFC-134a）和二氟甲烷（HFC-32）的方法,以1,1,1-三氟-2-氯乙烷（HCFC-133a）、二氯甲烷（HCC-30）及无水氟化氢（AHF）为原料,通过气相氟化催化一步反应可同时生产1,1,1,2-四氟乙烷和二氟甲烷。     

CFC替代品HFC-152a开发研究

对氯氟烃 (CFCS)替代品HFC -15 2a进行了工业性试验研究 ,论述了以氯乙烯为原料生产HFC -15 2a的氟化反应原理和规律性 ,介绍了工艺过程和主要操作参数 ,为工业化生产提供了依据     

HFC245fa水平光管与强化管管束外冷凝换热

试验研究了新型环保工质HFC245fa在光管与强化换热管管束上的冷凝换热特性。试验管束由4列排深为5排的列管构成,换热管公称外径为19.05mm、有效换热长度为1000mm。试验中,通过改进的Wilson图解法获得强化换热管水侧对流传热系数,利用2接点温差电偶测试蒸气与冷却水温差(±0.025℃),利用热电偶通过小周期标定法获取试验管进出水温差(±0.01℃);考察了冷凝温度、热通量对冷凝换热的影响。研究结果表明:HFC245fa在光管单管外冷凝传热系数与Nusselt模型预测值一致性较好;同热通量下,强化换热管单管上的冷凝传热系数为光管的13.5倍;光管管束上的试验结果比Nusselt管束模型预测值高20%～50%;强化管冷凝换热性能受作用热通量的影响较大。试验结果对工质与新管材推广、应用具有指导意义。     

Condensation heat transfer coefficients of flammable refrigerants on various enhanced tubes

In this study, external condensation heat transfer coefficients (HTCs) of six flammable refrigerants of propylene (R1270), propane (R290), isobutane (R600a), butane (R600), dimethylether (RE170), and HFC32 were measured at the vapor temperature of 39°C on a 1023 fpm low fin and Turbo-C tubes. All data were taken under the heat flux of 32- 116 and 42-142 kW/m² for the Iow fin and Turbo-C tubes respectively. Flammable refrigerants’ data obtained on enhanced tubes showed a typical trend that external condensation HTCs decrease with increasing wall subcooling. HFC32 and DME showed up to 30% higher HTCs than those of HCFC22 due to their excellent thermophysical properties. Propylene, propane, isobutane, and butane showed similar or lower HTCs than those of HCFC22. Beatty and Katz’ correlation predicted the HTCs of the flammable refrigerants obtained on a low fin tube within a mean deviation of 7.3%. Turbo-C tube showed the best performance due to its 3 dimensional surface geometry for fast removal of condensate.     

HFC125临界循环热泵的理论分析

通过构造一个逆劳伦兹循环来作为临界循环热泵的理想循环，以HFC125为例计算临界循环热泵的各部分不可逆损失，并与常规热泵进行了比较。在要求供水有较大温升的条件下，HFC125临界循环比常规循环的节流损失和高温换热损失要低得多，因此其循环的性能系数要比常规循环高，但其工作压力也较高。     

R404A在螺杆冷水机组中替代R22的性能试验研究

为研究HFCs非共沸混合制冷剂R404A(R125／R143a／R134a，44／52／4Wt％)替代R22的可行性和适用性，将：R404A充入LSLG16开启式螺杆冷水机组(原为R22)，并在不同工况下进行性能试验。试验结果表明，与R22螺杆冷水机组相比R404A机组的制冷量、消耗功率、冷凝器和蒸发器的传热系数均在不同程度上有所增加，COO略有下降。     

混合制冷剂HFC152a/HFC125的电冰箱实验研究

对环保节能制冷剂——二元近共沸混合工质HFCl52a／HFC125在电冰箱上应用的制冷循环性能进行了详细的理论计算和分析，并且对该工质灌注式替代CFC12和HFC152a／HCFC22在不同配比和充灌量下的电冰箱主要制冷性能进行了实验研究。实验结果表明：在合适的配比和充灌量下电冰箱制冷性能指标满足国家标准要求。混合制冷剂HFC152a／HFC125优良的环保性能和冰箱制冷性能使它完全适合做新一代的冰箱制冷剂。