铁路沿线供暖用低温空气源热泵热力性能对比研究

我国北方铁路沿线站段冬季采暖主要以燃煤锅炉为主,随着冬季雾霾现象日益严重,采用空气源热泵作为北方铁路沿线传统燃煤锅炉供暖的替代方式,对于减少能源消耗、改善大气环境具有重要意义。研究跨临界CO2热回收热泵和回热循环热泵系统2种低温空气源热泵系统,对其热力性能进行了实验和对比分析。结果表明,当环境温度不变时,随着供水温度由45℃升高至55℃,跨临界CO2热回收热泵制热量和COP均升高;随着供水温度由45℃升高至50℃,回热循环热泵制热量和COP均逐渐降低。当供水温度低于50℃时,回热循环热泵COP高于跨临界CO2热回收热泵,回热循环热泵系统的节能效果更为显著;当供水温度超过50℃时,跨临界CO2热回收热泵的性能更优。在低温环境条件下,跨临界CO2热回收热泵系统能够提供更高的供水温度,并有效提升空气源热泵的制热性能,结合我国北方铁路沿线站段的供暖需求和气候条件,提出相较于回热循环热泵系统,跨临界CO2热回收热泵系统的适用性和热力性能更为优越。

Thermodynamic Performance Investigation of Low Ambient Temperature Air Source Heat Pump Using in Railway System for Space Heating

Coal-fired boilers are mainly used for heating in winter in stations along the northern railway in China.With the increasing smog in winter,the use of air source heat pump as an alternative to traditional coal-fired boilers for heating along the northern railway is of great significance for reducing energy consumption and improving the atmospheric environment.Two kinds of low temperature air source heat pumps system,transcritical CO2 heat recovery heat pump and regenerative cycle heat pump system,are studied,and their thermodynamic performance is tested and compared.The results show that when the ambient temperature is constant,the heat production and COP of the transcritical CO2 heat recovery heat pump increase with the increase of the water supply temperature from 45℃to 55℃.As the water supply temperature rises from 45℃to 50℃,the heat production and COP of the regenerative cycle heat pump gradually decrease.When the water supply temperature is lower than 50℃,the COP of the regenerative cycle heat pump is higher than that of the transcritical CO2 heat recovery heat pump,the energy saving effect of the regenerative cycle heat pump is more significant.When the water supply temperature exceeds 50℃,the performance of the transcritical CO2 heat recovery heat pump is better.Under low temperature environment,the transcritical CO2 heat recovery heat pump system can provide higher water supply temperature and effectively improve the heating performance of the air source heat pump.Combined with the heating demand and climate conditions of stations along the northern railway in China,it is pointed out that the applicability and thermal performance of the transcritical CO2 heat recovery heat pump system are superior to that of the regenerative cycle heat pump system.