Development of an organic Rankine cycle-based micro combined heat and power system for residential applications

Abstract

Micro combined heat and power systems can achieve higher overall energy efficiencies than conventional home heating appliances. In the present paper, a prototype compact organic Rankine cycle-based micro combined heat and power system is built and tested for use in residential houses in order to increase energy efficiency and security. The heat generated by the energy system is used for both space heating and domestic hot water. The organic Rankine cycle’s working fluid is n-Pentane. At nominal operating conditions, the system generates 1.0 kWe of electricity of which 0.65 kWe can be used in the house or exported to the grid. Its heat output ranges from 7.0 to 14.0 kWth. A thermodynamic model for the organic Rankine cycle is developed to determine its thermodynamic performance under varying operating conditions. The model is then used to calculate the power output and energy conversion efficiency. The advantages of the micro combined heat and power system include a high overall energy efficiency, automated operation, low maintenance, low noise levels, and compactness. The value provided to the end-user by this integrated system is found in both its reliability and independence from the electrical grid.