Thermodynamic performance evaluation and experimental study of a Marnoch Heat Engine

Abstract

The Marnoch Heat Engine (MHE) is a recently patented type of new heat engine that produces electricity from lower temperature heat sources. The MHE utilizes lower temperature differences to generate electricity than any currently available conventional technologies. Heat can be recovered from a variety of sources to generate electricity, i.e., waste heat from thermal power plants, geothermal, or solar energy. This thesis examines the performance of an MHE demonstration unit, which uses air and a pneumatic piston assembly to convert mechanical flow work from pressure differences to electricity. This thesis finds that heat exchangers and the piston assembly do not need to be co-located, which allows benefits of positioning the heat exchangers in various configurations. This thesis presents a laboratory-scale, proof-of-concept device, which has been built and tested at the University of Ontario Institute of Technology, Canada. It also presents a thermodynamic analysis of the current system. Based on the MHE results, component modifications are made to improve the thermal performance and efficiency. The current configuration has an efficiency of about thirty percent of the maximum efficiency of a Carnot heat engine operating in the temperature range of 0oC to 100oC. The analysis and experimental studies allow future scale-up of the MHE into a pre-commercial facility for larger scale production of electricity from waste heat.