Around the world the implementation of heat recovery systems play an increasingly important role in the engineering industry. Recovered energy is utilised in production plants (especially in the food industry) and saves companies millions in expenses per year. Waste heat recovery associated with hydrocarbon combustion in the transport industry is identified as a significantly under-utilised energy resource. The aim of this project was to investigate the recovery of waste heat in a small scale system for the purpose of electrical conversion in order to serve as a secondary energy source. A theoretical analysis concerning the design and construction of the system, utilising researched theory and a control-volume-based simulation program of the recovery system, is presented. It was found that heat exchangers for the required duty are not readily available in South Africa. A high pressure, cross flow, stainless steel finned tube heat exchanger with a water side pressure rating of 2 MPa was therefore designed and constructed. By using the exhaust gases of a continuous combustion unit as an energy source and water as the working fluid, efficiencies of up to 74% in direct steam generation testing were obtained.
Stainless steel finned tube heat exchanger design for waste heat recovery
