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THERMODYNAMIC PERFORMANCE LIMIT AND EVAPORATOR DESIGN CONSIDERATIONS FOR NARM-BASED DOMESTIC REFRIGERATOR-FREEZER SYSTEMS
Citation:
Smith, M., M. Heun, R. Crawford, AND T. Newell. THERMODYNAMIC PERFORMANCE LIMIT AND EVAPORATOR DESIGN CONSIDERATIONS FOR NARM-BASED DOMESTIC REFRIGERATOR-FREEZER SYSTEMS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-92/213 (NTIS PB93106821), 1990.
Description:
The paper gives results of an investigation of non-azeotrophic refrigerant mixtures (NARMs) for a two-temperature-level heat exchange process found in a domestic refrigerator-freezer. deal (constant air temperature) heat exhcange processes are assumed. he results allow the effects of intercooling between the evaporator refrigerant stream and the condenser outlet stream to be examined systematically. or the conditions studied, an idealized NARM system has a limiting coefficient of performance (COP) that is less than that of the best performing pure refrigerant component. owever, for non-ideal heat exchange processes (gliding air temperature), the NARM-based system has a higher limiting COP than a system running on either NARM component. ntercooling significantly affects the COP of the NARM-based systems; however, depending on the location of "pinch points' in the heat exchangers, only one intercooling heat exchanger may be needed to obtain a NARM's maximum refrigerator COP. hree refrigerant pairs, R22/R142b, R22/R123, and R32/R142b, were studied, but the results for only R22/R123 are presented because of its unique temperature glide curvature. ractical implementation of a Lorenz cycle constrains evaporator design. n evaporator module design is presented which meets the NARM system constraints.
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THERMODYNAMIC PERFORMANCE LIMIT AND EVAPORATOR DESIGN CONSIDERATIONS FOR NARM-BASED DOMESTIC REFRIGERATOR-FREEZER SYSTEMS