DESIGN OF WASTE HEAT RECOVERY SYSTEMS BASED ON SUPERCRITICAL ORC FOR POWERFUL GAS AND DIESEL ENGINES

asme-orc2015 Tracking Number 26

Nowadays the scientific world community is strongly concerned about problems of efficiency increase and emissions reduction of Internal Combustion Piston Engines (ICPE). The equipment of ICPE with Waste Heat Recovery Systems (WHRS) is an effective solution for the aforementioned problems. This paper focuses on finding the maximum possible heat recovery from the available high and low temperature waste heat flows of a powerful ICPE to produce the maximum amount of additional power while decreasing the load on the engine’s cooling system. Having considered and analyzed existing works devoted to the development of WHRS the most effective ideas were combined to design several thermodynamic cycles for new WHRS of powerful piston engine (here a G3612 CAT gas petroleum engine is considered). The proposed WHRS is based on a Supercritical Organic Rankine Cycle (SORC) using R245fa as the working fluid where heat is extracted from the waste heat sources by a refrigerant at different pressure levels. Internal recuperation is used to further improve the cycle performances and increase the waste heat recovery. The thermodynamic analysis of the new WHRS showed that up to 19.5% of power boost for the internal combustion engine can be achieved without burning additional fuel which represents significant gains in terms of specific power. In order to quantify the estimation of the performances for proposed cycles the design of a traditional, high efficiency, WHRS based on double pressure water steam cycle for the same engine's conditions was performed. This comparison of performances between the steam cycle and the SORC R245fa cycles confirmed a high potential for the designed cycles.