Development and Experimental Study of Air Source Heat Pump Water Heater

The principle and development prospect of air source heat pump water heat were introduced,as well as the designation of condenser (storage water tank),experimental study on installations was also carried out.The results showed that air source heat pump water heater was superior to conventional system.Under the operation of cooling and heating,heat pump comprehensive utilization equipment could improve heating performance,reduce energy consumption,and recycle condensing heat to provide hot water.

Experimental study on characteristics of transcritical heat pump water heater using refrigerant HFC125

To evaluate the performance of heat pumps using refrigerant HFC125,an experimental rig of a DC-inverter heat pump water heater is designed and set up,and the research on the transcritical heat pump water heater is carried out experimentally.It is found that there is a top value of the coefficient of performance（COP）when the system runs at 95 Hz of frequency.The relationships between the COP and compressor frequency,condensation pressure,evaporation pressure,condensation water temperature rise,and discharge temperature are discussed and analyzed at 95 Hz.And the COP of the HFC125 transcritical cycle is also compared with that of a R410 subcritical heat pump under the same conditions.The results indicate that there exists an optimum frequency for a better COP,and the system COP shows an increasing tendency with the decrease in condensation pressure and compressor ratio while the evaporation pressure remains invariant,and the COP decreases rapidly when cooling water temperature rises over 47.5 ℃.Compared with the R410A sub-critical cycle,the COP of HFC125 transcritical cycle significantly increases by 12% on average.

Experimental Study of Thermoelectric Heat Pump Water Heater with Exhaust Heat Recovery from Kitchens

A new kind of thermoelectric heat pump water heater for kitchens exhaust heat recovery was presented,and its performances were investigated under different operating voltages.The experiment results show that the coefficient of performance decreases and the temperature difference between the hot and cold sides becomes larger with the increase of the operating voltage,but the heating time becomes short.The higher the temperature of water,the greater the temperature difference between the hot and cold sides,leading to a smaller coefficient of performance.Under an exhaust temperature of 36 ℃,the coefficient of performance decreases from 1.66 to 1.22 when the temperature of water increases from 28 ℃ to 46 ℃ with operating voltage 16 V.Performance tests illustrate that,compared with the conventional electrical water heaters,the new kind of thermoelectric heat pump water heater is more coefficient.

Numerical and Experimental Study on Dynamic Performance of Heat Pump Water Heater with Electronic Expansion Valve

A series of experiments on the dynamic performance of the HPWH （heat pump water heater） unit with EXV （electronic expansion valve） under different environmental conditions were conducted. The dynamic heating capacity and COP （coefficient of performance） of the HPWH unit under different EXV openings were measured. The effects of the EXV opening on the performance of the HPWH unit were analyzed. Meanwhile, the dynamic performance of the HPWH with EXV was simulated and the results were compared with the experimental one. The experimental results indicate that during heating process, the COP increases firstly and then decreases for a fixed EXV opening, which is in good agreement with the numerical result. For different EXV openings, the COP and heating capacity of the system using larger EXV opening are superior to those using the smaller one in the initial heating stage. While in the late stage, the performance of system using smaller EXV opening is better. It is found that the system performance is improved significantly by changing the EXV opening in the different heating period and the average COP of the HPWH system is increased by 7.6%.

Performance and Optimization of Air Source Heat Pump Water Heater with Cyclic Heating

A new type of microchannel condenser applied in the air source heat pump water heater(ASHPWH)with cyclic heating was proposed in this study.The operating performance of the ASHPWH was frst tested.Then,the structure of the microchannel condenser was optimized with the implement of vortex generators.Finally,a numerical model of the ASHPWH was established and the optimized microchannel condenser was studied.The experimental results showed that the average coefficient of performance(COP)of the 1HP(735 W)ASHPWH reached 3.48.In addition,the optimized microchannel condenser could be matched with a 3 HP(2430W)ASHPWH with an average heating capacity of 10.30 kW,and achieving an average COP of 4.24,14.6%higher than the limit value in the national standard.

家用空气源热泵热水器微通道冷凝器仿真研究

为提升家用空气源热泵热水器水箱外微通道冷凝器的性能,建立了家用空气源热泵热水器水箱外微通道冷凝器的准稳态模型,实验验证结果显示模型误差能控制在±9%以内。依据模型对微通道冷凝器的换热量、换热系数、压降等性能进行仿真研究。结果发现,微通道冷凝器为四流程时能够减小压降并保证换热量满足需要;关键参数微通道截面的最佳尺寸在1.6~2.6 mm^(2)系统性能最优,同时扁管内微通道数应控制在16~24根。研究结果为家用空气源热泵热水器微通道冷凝器的设计提供借鉴。

风机转速对CO_(2)空气源热泵热水器性能影响的试验研究

为了定量探究CO_(2)空气源热泵热水器系统性能随风机转速的变化规律,通过试验研究了不同工况下,改变风机转速对排气压力、过热度、CO_(2)质量流量、系统制热量、系统总功耗以及制热性能系数COP的影响;利用响应曲面法对试验进行了优化分析,同时利用试验数据拟合了COP回归模型,并进行可信度分析;通过回归模型预测了系统的最优运行工况并进行试验验证。结果表明:在压缩机频率和电子膨胀阀(EEV)开度一定的情况下,存在着最佳风机转速;在45~85 Hz范围内,随着压缩机频率的提高,COP先增大后减小,增幅最高可达8.97%,各频率下COP最大时对应的最佳风机转速不断减小;随着EEV开度在35%~55%范围内不断增大,COP先增大后减小,增幅可达到6.6%,各EEV开度下COP最大时对应的最佳风机转速不断增大;当压缩机频率为65 Hz、EEV开度为50%时,对应的最佳风机转速为1000 r/min,系统COP达到峰值(4.09)。本文所拟合的COP回归模型最大误差为4.5%;预测系统最优运行工况为:压缩机频率68 Hz、EEV开度52%、风机转速956 r/min,此时系统COP最大,可达到4.29,预测误差为3.7%。本研究可为CO_(2)空气源热泵热水器系统保持高效运行提供理论指导。

带气液调配蒸发器空气源热泵热水器的实验研究

气液调配蒸发器通过调整干度和质量流速实现传热性能提升。分别将两个管程布置为4-2-4-6-4(蒸发器1)和5-4-3-4-4(蒸发器2)的气液调配蒸发器用于热泵热水器中(分别为系统A和系统B)进行实验,并进行了对比研究。结果表明:相比于蒸发器1,蒸发器2制冷剂分布更均匀,且蒸发器侧压降减小了10.91%。在名义工况下,相比于系统A,系统B制热量减少1.69%,功率也减少1.45%,两个系统COP基本相同。系统B的排气压力比系统A小26.35~84.78 kPa,更有利于压缩机的安全运行;在不同的环境温度下,系统B的压缩机功耗均小于系统A,当环境温度为30℃时,系统B的性能比系统A提高了2.1%。

采用电子膨胀阀和毛细管的空气源热泵热水器性能对比实验研究

为研究不同节流方式对空气源热泵热水器性能的影响,分别以毛细管(CAP)和电子膨胀阀(EEV)作为节流元件研制了样机,通过实验对比研究其运行特征。结果表明:CAP系统的吸气过热度能稳定在1℃左右;CAP系统的排气温度相对更低,约比EEV系统低15℃;加热同样一箱水,CAP系统的制热速度更快;EEV系统的COP和全年性能系数(APF)均高于CAP系统,但在名义工况下CAP系统具有与EEV系统相当的制热COP。综合考虑制热性能及初投资等因素,可根据需要优先采用毛细管作为节流装置。

一款改进的家用热回收空调热力性能实验研究

为提高家用空调器利用率并节能减排,通过改进得到一款具有制冷、供暖、全天候供热水和冷凝热回收制取热水四种功能的热回收空调器。热力性能实验结果表明,改进后的热回收空调器各模式运行可靠,节能效果显著。

热泵热水器不锈钢内胆激光焊接工艺应用研究

通过工艺实验研究可调环模激光焊接方法应用于热泵热水器不锈钢水箱内胆焊接可行性,在不改变现有内胆制造过程的前提下,提出一套适应热泵热水器不锈钢内胆的激光焊接工艺,提高热泵热水器不锈钢内胆焊接效率和焊接质量。经验证采用可调环模激光焊接方法,正离焦量为20 mm,外环激光能量占比达到30%时,可满足热泵热水器不锈钢水箱内胆可靠稳定焊接。增加反射预热板,可有效改善焊缝成形,提高激光能量利用率。

GB/T21362-2023《商业或工业用及类似用途热泵热水机》标准解析

GB/T21362-2023《商业或工业用及类似用途热泵热水机》标准于2023年3月17日发布,于2023年10月1日起实施,替代原标准GB/T21362-2008。新版标准在结构、编辑性和技术内容方面做了重大调整,本文主要对GB/T21362-2023标准的修订内容及新旧标准的主要差异进行解析,有助于企业技术人员和检测机构学习掌握新的测试方法。

家用和类似用途空气源热泵热水器热工性能测试分析

为更好地理解GB/T 23137—2020《家用和类似用途热泵热水器》,并准确测试空气源热泵热水器的热工性能,对空气源热泵热水器性能测试和计算方法进行解读。首先,为保证空气源热泵热水器性能测试的准确性,建议对标准中公式的疏漏进行修正,标准中对同一物理量的定义和单位应统一,同时,考虑大气压对测试结果的影响。其次,分析空气源热泵热水器热工性能相关参数的计算方法,指出采用单一发生时间获得的性能指标对热泵热水器进行评价存在局限性。最后,指出应及时更新空气源热泵热水器的能效标准或产品标准,使其评价机制保持一致。

Performance analysis of air-water dual source heat pump water heater with heat recovery

A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot water.The hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the system.This experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner laboratory.The hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ separately.The results showed that the system operated stably and reliably.This system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump system.Its energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

寒冷地区空气源热泵辅助太阳能热水器供暖性能

为提高太阳能热水器供暖的稳定性并大幅降低空气源热泵供暖的成本,提出空气源热泵辅助太阳能真空管热水器供暖构想,在甘肃省兰州市七里河区魏岭乡绿化村搭建空气源热泵辅助太阳能热水器供暖试验系统,详细研究了晴天、阴天及多云3种典型工况下系统的集热效率、热泵性能系数、系统太阳能保证率和系统能效比等.研究结果表明,晴天、阴天及多云工况下太阳能集热器有效得热量分别为75.5、4.1和49.2 kW·h,集热效率分别为61.3%、26.6%、55.2%,太阳能热泵平均性能系数(COP)分别为3.6、3.4、3.6,空气源热泵平均COP分别为0、2.9、3.1,系统实际供热量分别为113.4、125.9和124.8 kW·h,系统耗电量分别为33.4、50.5和42.7 kW·h,系统太阳能保证率分别为66.6%、3.3%、39.4%,系统能效比分别为3.4,2.5,2.9.研究证明了太阳能真空管集热器-空气源热泵系统用于寒冷地区供暖的可行性,为寒冷地区供暖提供了一种新途径.

R744混合工质热泵热水器系统性能研究

为了寻找用于热泵热水器的低GWP替代工质,构建了基于EES软件的热泵热水器系统性能预测模型,并对其可靠性进行了验证。通过对比分析循环性能,理论评价了6组R744环保混合工质在直热式热泵热水器中替代R22的可行性。结果表明:工质浓度对R744混合工质热泵热水器的循环性能具有显著的影响,且所有R744混合工质均存在最优质量浓度使其系统分别获得最大COP_(th);相比于R22系统,R744/R290和R744/R1270系统在最优质量浓度14/86下均获得了显著提升的COP_(th)和制热量以及较低的排气温度,因此R744/R290(14/86)和R744/R1270(14/86)在直热式热泵热水器中均具有显著的替代优势;其余4组混合工质均不适宜在直热式热泵热水器中作为替代工质。本研究拓宽了热泵热水器用环保工质的选择范围,并为其工质替代提供参考依据。

热泵热水器欧盟能效标识及生态设计指令解读

欧盟是我国热泵热水器产品主要的出口地之一,在欧盟出口和销售的热泵热水器产品要求强制加贴能效标识并应满足生态设计指令要求。为了使相关人员理解热泵热水器的能效标识以及生态设计指令相关要求,本文通过分类、归纳总结、对比,分析热泵热水器能效标识相关参数的确定、生态设计要求、市场监督要求,以及我国相关标准与欧盟的差异。

空气源热泵热水器在寒冷地区冬季的能效分析

对一台家用空气源热泵热水器进行冬季性能测试,研究室外空气温度、水箱温度不同时机组性能变化。基于测试数据分析影响机组性能的敏感因素,依据所得天津地区实测数据分析其冬季平均能效。结果表明:COP最低为1.30,具有节能效果;保证用水舒适度及机组运行稳定的情况下,45℃为水箱最佳设定温度;室外空气温度偏移较水箱平均温度偏移对系统性能更敏感;测试工况下热泵机组单独工作和启动电辅加热时全冬季的平均能效相差甚微,若用户设定机组在日最高温度时段开启加热,能获得更好的节能效果。

跨临界CO_(2)空气源热泵热水器性能研究

为进一步研究CO_(2)空气源热泵的系统性能,文中以跨临界CO_(2)热泵热水器为研究对象,实验分析压缩机频率、排气压力和水流量对系统性能的影响,以及气冷器入口参数对气冷器螺旋盘管沿程换热的影响。结果表明:随着水流量的增加,压缩机功率、压比以及水侧出口温度都呈下降趋势,而系统制热性能系数(COP)呈上升趋势,由于CO_(2)在放热过程中存在温度滑移现象,因此随着排气压力的升高,其气冷器出口焓值出现显著变化,系统COP、水侧出口温度以及系统制热量呈先上升后下降的趋势。为保证生活热水需求和较高的系统性能,选择了系统COP与水侧出口温度交点所对应的水流量为最佳水流量。研究发现气冷器螺旋槽管换热系数峰值的变化与雷诺数的变化成正比、与入口压力的变化成反比,提高质量流量有利于气冷器的换热性能。