近年来，随着可用热泵热水器产品的激增，人们对热泵热水器作为节能和成本节约设备的兴趣增加。传统的电阻水箱加热器理论上的最大COP为1，而热泵热水器可以为系统使用的每单位电能向水输送多个单位的热能。热泵热水器尤其引起了电力公司的兴趣，他们认为热泵热水器是一种潜在的节能和降低峰值负荷的资产。然而，现代热泵热水器有其局限性。在大负载和环境温度较低时，它们通常依靠电阻热提供备份。 使用二氧化碳作为制冷剂的热水器已经解决了其中一些问题，但由于各种原因尚未在美国出现。本文描述了热泵热水器系统的建模，包括使用变速压缩机消除R134a系统中电阻元件的潜在下一代系统。为了评估不同系统和控制策略的性能，需要高水平的详细信息，因此使用商用方程求解工具在部件级别对热泵循环进行建模。在这项工作中，对使用R134a和定速压缩机的蒸汽压缩循环以及带有可变流量的R134a热泵进行了建模- 高速压缩机和二氧化碳跨临界变速热泵。换热器几何结构、传热和压降相关性以及压缩机和风扇效率都是基于可用的制造商数据考虑的。瞬态仿真软件工具用于模拟天气、建筑物和水箱，并与蒸汽压缩循环模型耦合，以模拟随时间变化的系统性能。本文详细介绍了几种热泵热水器设计的建模方法和仿真结果，这些设计使用了多种控制算法，并在多种气候条件下运行。初步结果表明，该模型的预测结果与项目发起人记录的实际现场测试数据吻合良好。 本文确定了许多控制算法和系统配置，这些算法和配置提供了潜在的节能，并量化了使用变速压缩机和二氧化碳作为制冷剂的潜在优势。引文:美国丹佛市ASHRAE会议论文

In recent years, interest in heat pump water heaters as energy- and cost-saving devices has increased, corresponding with a recent surge in available heat pump water heater products. While a traditional electric resistance tank heater can offer a theoretical maximum COP of 1, heat pump water heaters can deliver several units of heat energy to water for every unit of electrical energy used by the system. Heat pump water heaters have, in particular, sparked the interest of electric utility companies, who see them as a potential energy-saving and peak load-reducing asset. However, modern heat pump water heaters have limitations. They generally rely on electric resistance heat to provide backup during large loads and when ambient temperatures are low. Water heaters using CO2as a refrigerant have addressed some of these issues, but have yet to emerge in the United States for a variety of reasons. This paper describes modeling of heat pump water heater systems, including a potential next generation of systems using variable speed compressors to eliminate the electric resistance element in R134a systems. A high level of detail is required in order to evaluate the performance of different systems and control strategies, thus the heat pump cycles were modeled at the component level using a commercially available equation solving tool. In this work, a vapor compression cycle using R134a and fixed-speed compressor was modeled as well as an R134a heat pump with a variable-speed compressor and a CO2-transcritical variable-speed heat pump. The heat exchanger geometries, heat transfer and pressure drop correlations, and compressor and fan efficiencies were all considered based on available manufacturer data. A transient simulation software tool is used to simulate the weather, building, and water tank and is coupled with the vapor compression cycle model in order to simulate system performance over time. This paper details the modeling approach and simulation results for several heat pump water heater designs which use a variety of control algorithms and operate in several climatic conditions. Initial results show good agreement between the model's predictions and actual field test data recorded by the project's sponsors. The paper identifies numerous control algorithms and system configurations which offer potential energy savings and also quantify the potential advantages of using a variable-speed compressor and CO2as a refrigerant.