Energy, exergy, environmental, and economic modeling of combined cooling, heating and power system with Stirling engine and absorption chiller

Abstract

Combined Cooling, Heating and Power system is one of the methods for improvement of primary energy using, reducing emissions and energy consumption costs compared to other usual energy supply systems. Because of the ability to use different fuel sources, lower noise and high efficiency, the Stirling engine has a great potential for Combined Cooling, Heating and Power system as prime mover. Hence, in this paper, a comprehensive analysis of this system with Stirling engine and absorption chiller has been proposed. This system has been evaluated from perspectives of energy, exergy, fuel consumption, carbon dioxide emissions and fuel costs at various rotational speeds of the Stirling engine and has been compared to usual energy supply system for buildings. Also, for the proposed system in different working conditions, the payback period is estimated. The modeling results illustrated that that the Coefficient of Performance (useful cooling capacity to required energy input) of absorption chiller, power output, heat loss, and exergy destruction reach to their maximum values during high rotational speeds. Also, the thermal efficiency, exergy efficiency, fuel consumption reduction, carbon dioxide emission reduction, and fuel costs reduction reach to their higher values at lower rotational speeds and the overall efficiency of the system reach to its maximum value at moderate rotational speeds. Therefore, based on different priorities, this system can be used at different engine rotational speeds. Also, with system operation of 6 h per day at the average engine rotational speeds, the payback period has been estimated less than 3 years.