Abstract:

In the context of the “carbon peaking and carbon neutrality” strategy, large temperature-lift heat pump technology can not only save energy in low carbon, but also effectively utilize lower grade heat energy to develop into higher temperature field. In this paper, the research progress of performance optimization of large temperature-lift vapor compression heat pump system (large temperature-lift system) is summarized, and the feasible optimization means of large temperature-lift system are analyzed from refrigerant, component, cycle optimization and demonstration verification. Currently, the commonly used refrigerants in practical engineering of large temperature-lift systems are still mainly high GWP value refrigerants such as R134a and R245fa; in terms of screening refrigerants with high temperature-lift, carbon dioxide (R744) in natural pure refrigerants has a wide temperature range and excellent performance; water (R718) is one of the potential refrigerants for breaking through the ultra-high temperature (150℃) limit in large temperature-lift systems; organic pure refrigerants have developed rapidly, with R1234ze(Z) and R1336mzz(Z) having extremely low GWP values and excellent thermodynamic properties; the preparation of R32-based, HFOs- based, and CO₂-based mixed refrigerants with low GWP values is currently a promising approach. In terms of component optimization, mature technologies such as compressor frequency conversion technology provide current solutions for optimizing components of large temperature-lift systems; the industrial products of magnetic bearing technology are becoming mature, which can effectively reduce the friction loss of large temperature-lift system; new component optimization ideas are provided by emerging technologies such as line structure heat exchanger technology for large temperature-lift system. In terms of cycle optimization, mature technologies such as vapour/liquid injection and multi-stage compression provide current schemes for loop optimization of large temperature lift system; the ejector technology and vortex tube technology have optimization effects on large temperature-lift systems, but are limited by the lack of engineering practical experience and unclear mechanism research. According to the demonstration and verification section, the technology of vapour injection is currently the most widely applicable and mature optimization technology for large temperature-lift systems in industrial application, and under certain conditions, it can increase the coefficient of performance value of large temperature lift systems by more than 20%; series multi-stage compression technology and cascade compression technology are powerful means to increase the temperature-lift range of the system and ensure low-temperature heating.

Key words: heat pump, large temperature-lift, vapor compression, optimization, system engineering

摘要：

在“双碳”战略的背景下，大温升热泵技术不仅低碳节能，而且能够有效利用更低品位热能，向更高温领域发展。本文概述了大温升蒸汽压缩式热泵系统（大温升系统）优化的研究进展，从制冷剂、组件、循环优化、示范验证四个方面详细分析了大温升系统可行的优化手段。分析表明：当前大温升系统实践工程的常用制冷剂仍以R134a、R245fa等高GWP制冷剂为主；而在大温升制冷剂筛选方面，自然纯制冷剂中二氧化碳（R744）适用温度范围广泛，性能表现优异；水（R718）是大温升系统突破超高温（150℃）限制的潜力制冷剂之一；有机纯制冷剂发展迅速，R1234ze(Z)、R1336mzz(Z)等具有极低的GWP与优异的热力学性质；制备R32基、HFOs基、CO₂基混合制冷剂低GWP的混合制冷剂是当前具有前景的思路；在组件优化方面，压缩机变频技术等成熟技术为大温升系统组件优化提供了现行方案；磁悬浮轴承技术工业产品走向成熟，可有效降低大温升系统摩擦损失；线结构换热器技术等新兴技术为大温升系统提供了新的组件优化思路；在循环优化方面，补气/补液增焓与多级压缩等成熟技术为大温升系统循环优化提供了现行方案；喷射技术与涡流管技术等研究成果对大温升系统具有优化效果，但受到工程实践经验缺少、机理研究不明等方面限制；结合示范验证部分，补气增焓技术是目前适用范围最宽泛、工业运用最成熟的大温升系统优化技术，一定条件下可提高大温升系统性能系数20%以上；串联多级压缩技术与复叠式压缩技术是提高系统温升范围、保障低温供暖的有力手段。

关键词: 热泵, 大温升, 蒸汽压缩, 优化, 系统工程