Stirling Engine Systems Tradespace Exploration Framework

Abstract

The purpose of this work is to propose a tradespace exploration framework for the design and system analysis of Stirling engines. The framework can be used to execute trade studies for different objectives. The framework obtains Pareto frontiers of optimal designs by evaluating performance (power, efficiency) and cost metrics for 750 Stirling engine design alternatives. The proposed system design framework integrates four domain models. An engine cycle thermodynamic model is to calculate engine cycle and performance parameters. A heat exchanger model is to estimate areas of heat exchangers. An economic model to predict the capital cost of the engine system. And a tradespace model based on five design parameters identified as drivers of the design: Stirling engine type (alpha, beta, or gamma), engine bore, stroke, hot space temperature, and cold space temperature. The results of the model shed insights on the design of Stirling engines and develop guidelines to identify the most suitable combinations of engine architectures and design parameters to address specific applications. The paper shows how the proposed framework can be applied to the design of Stirling engines for two different applications, namely waste heat recovery and combined heat and power generation for residential real estate units. Considering the identified customer needs for these two applications, the results of the study indicate that alpha-type Stirling engines are more appropriate for industrial waste heat recovery, e.g. heat treating furnaces and cement kilns, having a power output 50% higher for a given efficiency then other engine types. Beta-type engines result more beneficial for residential combined heat and power generation. Gamma-type engines result advantageous for low power applications such as toy models and tool kit engines.