Optimal sizing for residential CHP system

Residential CHP systems have been introduced around Japan recently, and expected to diffuse more and more. During the process of boosting the adoption of residential CHP systems, both manufacturers and customers are interested to know the optimal capacity of power generator for the unit, and once the unit has been installed, what dispatch strategy to use in order to minimize a customer’s cost of meeting its electricity and heat requirements. In this paper, a mixed integer nonlinear programming model has been developed. The objective is to minimize annual cost of the energy system for a given residential customer equipped with the CHP plant, combining with a storage tank and a back-up boiler. The model reports the optimal CHP system capacities that customers could employ given their electricity and thermal requirements. Using this model, an investigation was conducted of economically optimal CHP investment for a prototypical residential building. Furthermore, a sensitivity analysis was elaborated in order to show how the optimal solutions would vary due to changes of some key parameters. In addition, as a main component of residential CHP system, the optimal size of the storage tank was analyzed.