Optimal design of trigeneration systems for buildings considering cooperative game theory for allocating production cost to energy services

Abstract

In the design of trigeneration plants for buildings, two fundamental issues must be addressed: the synthesis of the plant configuration (installed technologies and capacity, etc.) and the operational planning. Given the variety of technology options available and great diurnal and annual fluctuations in energy demands, finding the optimal supply system of energy services is a complex task.Cost allocation in multi-product systems requires special attention because the way in which allocation is made will affect the prices of the final products and, consequently, the consumers' behaviour. When a polygeneration plant is designed to serve different products, it is possible to achieve a lower total cost. However, if potential consumers are free to participate, the system's management should ensure that every participant shares the benefit of joint production. In trigeneration systems this implies that all consumers should achieve, at least, a lower cost for their demanded energy services than operating separately.The present work proposes a Mixed Integer Linear Programming model to determine the optimal configuration of trigeneration systems that must cover the energy demands of electricity, heating and cooling of a residential complex located in Zaragoza, Spain. The model considers the possibility of using a set of proposed alternative technologies within a superstructure and considers the optimal operation throughout a typical meteorological year. The objective function to be minimized is the total annual cost.The results indicate that compared to consumers standing alone, the optimal trigeneration system can achieve 10.6% cost saving. Ten different cost assessment methods to the three final energy products of the analyzed trigeneration system are rigorously compared. Cooperative game theory shows that all consumers benefit. Using the Shapley values as the distribution criterion, the savings for electricity, heating and cooling consumers are 4.8%, 20.9% and 11.1%, respectively.