THE EFFECT OF THE OVERALL HEAT-TRANSFER COEFFICIENT VARIATION ON THE OPTIMAL DISTRIBUTION OF THE HEAT-TRANSFER SURFACE CONDUCTANCE OR AREA IN A STIRLING ENGINE

This study aims to assess for a Stirling engine the influence of the o verall heat transfer coefficient variation on the optimum state and on the optimum distribution of the heat transfer surface conductance or area among the machine heat exchangers. The analysis is based on a Sti fling machine optimization method, previously elaborated, which is now applied to a cycle with total heat regeneration. The method was conce ived for an irreversible cycle with heat transfer across temperature d ifferences at the source and the sink, and heat losses between the hot -end and the cold-end of the engine. Source and sink of finite thermal capacity as well as thermostats are considered. The new approach cons iders a linear variation of the overall heat transfer coefficient of t he machine heat exchangers with respect to the local temperature diffe rence. A comparison of the optimum state and the optimum distribution of the heat transfer surface conductance or area among the heater and the cooler is made for several cases. (C) 1998 Elsevier Science Ltd. A ll rights reserved.