Modelling and Thermodynamic Analysis of a Hot-Cold Conversion Pipe Using R134a-DMF-He as the Working Pair
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https://doi.org/10.1007/s11630-020-1243-0
Article ID: 1003-2169(2020)00-0000-00
Modelling and Thermodynamic Analysis of a Hot-Cold Conversion Pipe Using R134a-DMF-He as the Working Pair LI Haiyu1, LIN Peng2, DU Shuai1*, WANG Liwei1 1. Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240, China 2. China Ship Development and Design Center, Shanghai 201108, China © Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract: Based on the concept of a diffusion absorption system, a hot-cold conversion pipe utilizing 1,1,1,2-tetrafluoroethane (R134a)-dimethylformamide (DMF)-helium (He) as the working pair is presented with the aim of cooling output by recovering the low-grade waste heat. The model of the hot-cold conversion pipe is established, in which a heat pipe is used to transfer the waste heat as the heat input. The equations of the thermodynamic properties of the working pair are established by equation of state method (EOS). The model of the hot-cold conversion pipe is built based on the mass, species and energy balance equations of each component. The direct conversion of heat to cold is achieved by the desorption, absorption, condensation and diffusion evaporation processes of R134a. The hot-cold conversion pipe is cooled by natural convection, which can be enhanced by chimney effect. The thermodynamic analysis is carried out to analyze the effect of the boundary conditions, i.e. the heat source temperature, the refrigeration temperature, and the environmental temperature, on the system performance. This paper provides a theoretical basis for actual application of the hot-cold conversion pipe in waste heat recovery field.
Keywords: diffusion absorption refrigeration, R134a-DMF-He, hot-cold conversion, waste heat recovery, thermodynamic analysis
1. Introduction Nowadays, the development of human society is threatened by the serious energy crisis and environmental problems. Improving primary energy efficiency and developing renewable energy sources are the main directions of energy strategies. Therein, the reuse of the low-grade waste heat dissipated by the industry is an effective method to improve the primary energy efficiency. Among the technologies of low-grade heat utilization, absorption refrigeration [1] is significant since it can be directly driven by the low-grade heat and
Received: Mar 21, 2019
AE: SUN Jie
gets rid of electrical restriction. The driving heat source includes steam, hot water and flue gas, etc., thus, attracting increasing attention and application. However, the solution of the absorption refrigeration system is usually circulated by solution pumps, involving electrical consumption up to 5% of the cooling capacity [2], and increasing the initial cost. To reduce the power consumption, diffusion absorption refrigerating (DAR) cycle was proposed [3]. The DAR system is composed of heat exchangers, and it is driven only by heat. The working fluid can be circulated with the assist
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