Exploration of the performance of a steam generation system based on a high-temperature heat pump with R245fa

doi:10.16085/j.issn.1000-6613.2024-0166

Abstract

Abstract:

High-temperature heat pump steam generation system has the potential to replace small coal-fired boilers, not only to meet the demand for steam above 110℃ in the industrial field, but also to reduce the carbon dioxide emissions of heating equipment. In this paper, a high-temperature heat pump steam generation system for R245fa was constructed. The performance of the system was investigated under the matching conditions of different evaporation temperatures (35—50℃) and condensing temperatures (95—125℃), as well as different heat source temperatures (45—65℃) and hot water/steam generation temperatures (95—120℃), and the effect of different heat source temperatures on the start-up state of the system was also investigated. The results showed that COP, η_iso, and η_vol generally showed a decreasing trend with the increase of the evaporation/condensation temperature difference. Compared with the conventional heat pump system, high-temperature heat pump system compression ratio level was higher, and the average level of this unit was 6.09, up to 8.28. The system isentropic efficiency and volumetric efficiency by the operating temperature of the unit was more pronounced. In this experiment, while the compression ratio basically stayed unchanged in the case of the evaporation temperature rises from 35℃ to 45℃, isentropic efficiency and volumetric efficiency decreases by 3.65% and 6.16%, respectively. COP, heat production decreased with the increase of the difference between the heat source temperature and the generated hot water/steam temperature. The direct evaporation principle of this unit made the generated steam pressure lower than 0.170MPa, and the equipment met the standard of normal pressure vessel. The heat source temperature had a certain effect on the change of the system refrigerant flow rate, but the magnitude of the effect was limited. Taking this unit as an example, when the heat source temperature changed from 50℃ to 60℃, the increase of system refrigerant flow rate due to the increase of heat source temperature was less than 5%. The load switching in the start-up process led to rapid changes in the system performance. The increase of heat source temperature accelerated the start-up speed of the system. The change of the heat source temperature from 45℃ to 65℃ reduces the time taken for start-up by 520s. There was a significant impact on the system startup stability, and too high or too low heat source temperature would reduce the system start-up stability. According to the stability analysis results, the suitable heat source temperature range for this unit was 50—60℃.

Key words: high temperature heat pump, R245fa, steam generation system, performance, start-up process

摘要：

高温热泵蒸汽发生系统具有替代小型燃煤锅炉的潜力，不仅可以满足工业领域对110℃以上蒸汽的需求，而且可以降低供热设备的二氧化碳排放量。本文搭建了R245fa制冷剂高温热泵蒸汽发生系统，探究了不同蒸发温度（35~50℃）与冷凝温度（95~125℃）匹配条件，不同热源温度（45~65℃）与产生热水/蒸汽温度（95~120℃）匹配条件下的性能表现，以及热源温度对系统启动状态的影响。结果表明，制热性能系数（COP）、η_iso、η_vol总体呈现出随蒸发/冷凝温度差值增大而减小的趋势；较常规热泵系统，高温热泵系统压缩比水平更高，本机组平均水平为6.09，最高可达8.28，且系统等熵效率与容积效率受机组运行温度的影响更加明显。在压缩比基本保持不变的情况下，蒸发温度由35℃上升至45℃，等熵效率以及容积效率分别下降3.65%、6.16%；COP、制热量随热源温度与产生热水/蒸汽温度差值增大而降低。本机组直接蒸发原理使得产生蒸汽压力低于0.170MPa，设备符合正常压力容器标准；热源温度对系统制冷剂流量变化有一定影响，但影响幅度有限。以本机组为例，热源温度由50℃变化至60℃时，系统制冷剂流量因热源温度升高引起的提升幅度小于5%；启动过程的负载转换会导致系统性能快速变化；热源温度的提高会加快系统的启动速度，热源温度从45℃变化至65℃，启动阶段所花时间减少了520s；热源温度对系统启动稳定性有明显影响，过高或过低都将降低系统启动稳定性。根据稳定性结果分析，本机组的合适热源温度为50~60℃。

关键词: 高温热泵, R245fa, 蒸汽发生系统, 性能, 启动过程

CLC Number:

TK212

WU Fengming, LI Shuaiqi, DAI Chunjiang, HE Shihui, CHEN Xiang, SONG Wenji, FENG Ziping. Exploration of the performance of a steam generation system based on a high-temperature heat pump with R245fa[J]. Chemical Industry and Engineering Progress, 2025, 44(2): 752-763.

吴锋明, 李帅旗, 戴春江, 何世辉, 陈翔, 宋文吉, 冯自平. 基于R245fa制冷剂高温热泵构建的蒸汽发生系统性能[J]. 化工进展, 2025, 44(2): 752-763.

Figures/Tables 15

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研究者	制冷剂	压缩机	制热量 /kW	热源温度/℃	生产热质温度/℃
邢子文等^[9]	R245fa	双螺杆式	40~150	55~80	90~105
贺龙彬等^[11]	R245fa	双螺杆式	80~170	50~75	90~120
Assaf等^[13]	R245fa	双螺杆式	300~500	20~70	80~100
Fleckl等^[19]	R1336mzz(Z)	往复式	12	30~80	80~145
Fukuda等^[20]	R1234ze(Z)	转子式	1.8	50~90	80~130
Moisi等^[21]	R600	活塞式	20~40	45~70	90~110
于晓慧等^[22]	BY-4	涡旋式	44~141	40~70	75~110
王如竹等^[23]	R718	双螺杆式	100~300	80~100	100~140
冯自平等^[24]	R744	转子式	10~25	0~30	55~85

研究者	制冷剂	压缩机	制热量 /kW	热源温度/℃	生产热质温度/℃
邢子文等^[9]	R245fa	双螺杆式	40~150	55~80	90~105
贺龙彬等^[11]	R245fa	双螺杆式	80~170	50~75	90~120
Assaf等^[13]	R245fa	双螺杆式	300~500	20~70	80~100
Fleckl等^[19]	R1336mzz(Z)	往复式	12	30~80	80~145
Fukuda等^[20]	R1234ze(Z)	转子式	1.8	50~90	80~130
Moisi等^[21]	R600	活塞式	20~40	45~70	90~110
于晓慧等^[22]	BY-4	涡旋式	44~141	40~70	75~110
王如竹等^[23]	R718	双螺杆式	100~300	80~100	100~140
冯自平等^[24]	R744	转子式	10~25	0~30	55~85

传感器/采集仪	量程	精度
压力传感器	0~4MPa	±0.01MPa
温度传感器	-200~350℃	±0.5℃
电磁传感器	0~1	±0.5%
电磁流量计	0~25m³·h^-1	±0.5%
三相功率仪	0.1~198kW	±0.5%
数据采集仪（温度）	-100~400℃	±0.01%
数据采集仪（电流）	0~1A	±0.004%

传感器/采集仪	量程	精度
压力传感器	0~4MPa	±0.01MPa
温度传感器	-200~350℃	±0.5℃
电磁传感器	0~1	±0.5%
电磁流量计	0~25m³·h^-1	±0.5%
三相功率仪	0.1~198kW	±0.5%
数据采集仪（温度）	-100~400℃	±0.01%
数据采集仪（电流）	0~1A	±0.004%

蒸发温度/℃	冷凝温度/℃
35	95~115
40	100~120
45	105~125
50	110~125