喷气增焓空气源热泵系统可显著提高系统低温性能，应用在寒冷地区时冬季环境温度普遍在−5℃以下，而且全年温度波动范围非常大，仅以名义工况（干球温度为7℃）评价系统性能，难以准确有效反映系统真实节能效果。为此在兰州地区建立了喷气增焓空气源热泵实验系统，实测不同环境温湿度条件下系统性能，结果表明系统COP在喷气电磁阀关闭时基本呈线性变化关系，瞬时COP可达6.5，在喷气电磁阀开启时COP衰减更为缓慢，瞬时COP在2.0左右；据此分段拟合出热泵COP的经验关联式，确定其适用范围，并进行实验验证，与本实验系统相比其平均相对误差在3%以内。%The enhanced vapor injection air source heat pump (EVI-ASHP) has better thermal performance at a low temperature, which has received much attention to supply hot water in cold region in recent years due to the growing space heating load and concern for environmental degradation. Environmental temperature is often below−5℃ in winter in cold region of China, and changes greatly throughout the year. Thus coefficient of performance (COP) under nominal working conditions (dry-bulb temperature of 7℃) is difficult to accurately reflect the actual energy-saving effect of the system. So, a set-up of EVI-ASHP system was built in Lanzhou, and thermal performance at different environmental temperatures and humidities was determined. COP of the EVI-ASHP system could reach above 6.5 when electromagnetic valve for vapor injection was off, and linear change of COP was observed. At a low temperature, when electromagnetic valve was on, COP was about 2.0. The fitting equations of the experimental data were obtained and verified, with average relative error below 3% compared with the experimental data from the set-up. An effective prediction method was established for thermal performance of the EVI-ASHP system at changeable environmental temperature and humidity, supplying a theoretical guidance for the application of the system in cold climate.
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