介绍了热泵性能计算机模拟研究的最新进展。这包括对循环损失、极端运行条件下的性能和除霜控制的分析。目的是更好地了解热泵运行，识别故障模式，并评估控制方案。研究的主要结果是:恒定等效延迟时间、ZD和关断期功率输入的循环退化符合许多实验观察到的特征，并在整个热负荷范围内具有良好的代表性。在20%负载和6 min的开启周期下，CD法的循环损耗比ZD法高出2-3%，在50%负载下为-5-4%。较大的差异适用于循环损失较大的情况，如盘管较大或循环率较高的热泵。制冷剂加注损失会降低系统性能。 毛细管系统通常具有电荷不敏感的工作状态，而带有热膨胀阀的系统则没有。随着电荷损失的增加，TEV系统的冷凝温度下降速度比帽管系统快。换热器上方空气流量的减少以及由此导致的盘管容量下降会增加冷凝温度或降低蒸发温度，从而导致质量流量和系统COP降低。分析了压缩机或膨胀装置引起的质量流量下降。前者导致空气制冷剂盘管温差减小，而后者导致温差增大。将空气-空气换热器从强制换热器改为重力换热器，同时保持换热器效率，表明性能在季节性基础上提高了约18%。实际数量还取决于系统的大小；i、 例如，尺寸过小的系统节省的钱更少。 评估了除霜循环开始前结霜时间对热泵性能的影响。季节性COP几乎不依赖于除霜的启动方式。与其他除霜策略相比，经评估的最佳结霜时间长度导致了更高的COP，除霜周期数比固定定时器系统低25-50%，但高于DP需求除霜系统。固定定时器控制系统的除霜周期数可能是DP按需除霜系统的2-4倍。讨论了基于微处理器的热泵逻辑控制的功能，以及在实验室和现场测试中的性能。引文:研讨会，ASHRAE交易，第86卷，第一部分，加利福尼亚州洛杉矶

Recent progress in computer simulation studies of heat pump performance is presented. This includes an analysis of cycling losses, performance under extreme operating conditions, and defrost controls. The objective was to achieve a better understanding of heat pump operation, recognize failure modes, and evaluate control alternatives. Main results of the study were:Cyclic degradation in terms of constant equivalent delay time, ZD, and off period power input agrees with many experimentally observed features and gives a good representation throughout the heating load range. It matched to agree at 20% load and 6 min. of on-period, the cycling losses with the CD-method are higher than the ZD-method by a systematic 2-3% at 50% load and -5 to -4% at 10% load. The larger differences apply to cases with larger cycling losses such as heat pumps with larger coils or operating at higher cycling rates.Loss of refrigerant charge degrades system performance. Capillary tube systems generally have charge insensitive operating regimes, whereas systems with thermal expansion valves do not. Condensing temperature drops faster with TEV systems than with cap tube systems as charge loss increases.Reduction of air flow over the heat exchangers and consequent drop in coil capacity increases condensing temperature or decreases the evaporating temperature leading to decreases in both mass flow and system COP.Mass flow decreases induced by either the compressor or the expansion device were analyzed. The former lead to decreases in the air-refrigerant coil temperature differences while the latter caused them to increase.Changing air-to-air heat exchangers from forced to gravity while maintaining the heat exchanger efficiency shows performance improvement of about 18% on a seasonal basis. The actual amount would also depend on how the system is sized; i.e.,undersized systems save less.The influence of frost build-up time before initiating the defrost cycle on heat pump performance was evaluated. The seasonal COP depends little on the way defrost is initiated. The evaluated optimum length of frost build-up time leads to a higher COP than other defrost strategies and the number of defrost cycles is 25-50% lower than fixed timer systems, but higher than the DP-demand defrost systems. The number of defrost cycles can be 2-4 times higher for fixed timer control systems than for DP-demand defrost systems.The functions of a microprocessor based heat pump logic control are discussed together with its performance in a number of lab and field tests.