Cooling and heating rate limits of a reversed reciprocating Ericsson cycleat steady state

The optimal cooling and heating rates for the reversed reciprocating Ericss on cycle with ideal regeneration are determined for heat pump operations. T hese limiting rates are based on the upper and lower thermal reservoir temp erature bounds and are obtained using time and entropy minimization procedu res from irreversible thermodynamics. Use is made of time symmetry (a secon d law constraint) to minimize cycle time. This optimally allocates the ther mal capacitances of the cycle and minimizes internal cycle entropy generati on. Although primarily a theoretical work, a very practical and extensive p arametric study using several environmentally friendly working fluids (neon , nitrogen and helium) is included. This study evaluates the relative contr ibutions of various system parameters to rate-optimized design. The coeffic ient of performance (COP), and thus the quantity of cooling or heating for a given energy input, is the traditional focus; instead this work aims at t he rate of cooling or heating in heat pumps under steady state conditions a nd using ideal gases as their working substances. The results obtained prov ide additional criteria for use in the study, design and performance evalua tion of employing Ericsson cycles in refrigeration, air conditioning and he at pump applications. They give direct insight into what is required in des igning a reversed Ericsson heat pump to achieve maximum heating and cooling rates, The choices of working,fluids and pressure ratios were found to be very significant design parameters, together with selection of regenerator and source-sink heat transfer parameters. The parameter most influencing bo th the heating and cooling mode COPs and the heat transfer rates was found to be the heat conductance of the thermal sink.