R245fa高温蒸气热泵理论与实验研究

Theoretical and Experimental Investigation on R245fa High-temperature Water Steam Heat Pump System

工业领域中高温蒸气的需求较大,由于小型锅炉的禁用、电锅炉的低能效及余热资源的浪费,因此高温热泵作为制取水蒸气的装置,有广阔的发展前景。本文设计了一种采用R245fa为工质的高温热泵系统与水蒸气制备装置,建立数学模型对系统及各部件进行模拟和性能预测,并搭建实验台研究其性能和运行参数随工况等的变化规律。结果表明:随着蒸发温度的上升,系统COP快速上升,相对值为0.55~1.3,上升速度逐渐减缓,制热量近似线性升高,排气过热度下降,换热温差显著上升;换热系数随着水流率的增加而增加,变化范围为1.7~2.8 k W/(m2·K)。

High-temperature steam is in great demand for many industrial applications. The electric boilers used to replace traditional boilers in rural areas are not efficient enough to be employed in large-scale steam production. Furthermore, a large amount of heat appears to be wasted in related industries, so the employment of high-temperature heat pumps is quite promising in producing high-temperature steam. In this paper, an R245fa high-temperature heat pump system is applied to the production of steam. A mathematical model is devel-oped to predict the performance of each component and the heat pump system, and an experimental investigation is also conducted. The results illustrate that, with an increase in evaporation temperature, the coefficient of performance （COP） and heat capacity increase, whereas the discharge temperature decreases. The relative COP ranges from 0. 55 to 1. 3 in the target operating conditions. The heat ex-change efficiency is observed to increase from 1.7 to a maximum of 2. 8 kW/（ m^2· K） as the water flow rate increases.