A model-based feasibility study of combined heat and power systems for use in urban environments

Abstract

In the United States, 40% of energy use was for electricity generation in 2011, but two thirds of the energy used to produce electricity was lost as heat. Combined heat and power systems are an energy technology that provides electrical and thermal energy at high efficiencies by utilizing excess heat from the process of electricity generation. This technology can offer a decentralized method of energy generation for urban regions which can provide a more reliable, resilient and efficient power supply, and has a lower impact on the environment compared to certain centralized electricity generation systems. In order for the use of combined heat and power systems to become more widespread and mainstream, studies must be performed which analyze their use in various conditions and applications. This work examines the use of a combined heat and power system with a microturbine as the prime mover in residential and commercial scenarios and analyzes the technical and economic feasibility of various system configurations. Energy models are developed for R1, R6 and 2-story office building scenarios using eQUEST, and these results give the electrical and thermal energy requirements for each building. Combined heat and power system models are then developed and presented for each scenario, and the building energy requirements and system component sizes available are considered in order to determine the optimal configurations for each system. The combined heat and power system models designed for each scenario are analyzed to find energy savings, water impacts, and emissions impacts of the system, and each model is examined for economic and environmental feasibility. The models created provide information on the most technically and economically efficient configurations of combined heat and power systems for each scenario examined. Data on system component sizing, system efficiencies, and environmental impacts of each system were determined, as well as how these scenarios compared to the use of traditional centralized energy systems. Combined heat and power has the potential to significantly improve the resiliency, reliability and efficiency of the current energy system in the U.S., and by studying and modeling its uses we more completely understand its function in a range of scenarios and can deploy the systems in a greater number of environments and applications.