Design and Analysis of Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System

Abstract

This paper proposes the configuration of an Organic Rankine Cycle (ORC) coupled to a solar domestic hot water system (SDHWS), with the purpose of analyzing the cogeneration capacity of the system. A simulation of the SDHWS was conducted at different temperatures, observing its performance to determine the amounts of useable heat generated by the solar collector; thus, from an energy balance, the amount of heat that may be used by the ORC could be determined. The working fluid that would be suitable for the temperatures and pressures given in the system were selected. The best fluid for the given conditions of superheated vapor at 120 °C and 604 kPa and a condensation temperature of 60 °C and 115 kPa was acetone. The main parameters for the expander thermodynamic design that may be used in such ORC were obtained with the possibility of generating 443 kWh of annual electric energy, with 6.65 % global efficiency of solar to electric power, or an overall efficiency of the cogeneration system of 56.35 % with a solar collector of 2.84 m2.

Economic appraisal of small‐scale solar organic Rankine cycle operating under different electric tariffs and geographical conditions

“…The pay pack duration and IRR for SORC with thermal storage tank is less than 6 years and 15%. In Reference 13, a simulation of SDHWS coupled with ORC was conducted at different temperature to observe the performance of such system for residential application. The simulation result the system could generate 443 kWh/year with 6.65% global efficiency and 56.35% efficiency of the cogeneration system with solar collector 2.84 m 2 .…”