Modeling and Simulation of Heat Pump Systems Combined with Solar Photovoltaic

Abstract

Renewable energy systems have received considerable attention as a sustainable technology in the building sector. Specifically, the use of ground-source heat pump (GSHP) and air-source heat pump (ASHP) for heating and cooling of buildings is increasing rapidly, and the combination with photovoltaic (PV) systems and heat pump systems provide energy savings and environmental benefits. This study investigates the feasibility of replacing conventional heating and cooling systems in a multifamily, residential building with GSHP and ASHP systems and their combination with PV. The integration of PV with GSHP and ASHP systems presents an opportunity for increased solar energy usage resulting in a reduction of electricity demanded and a reduction of emissions of greenhouse gases. To analyze different heat pumps systems with and without PV, system modeling and computer simulations are performed with RETScreen Expert software.A multifaceted verification and validation study is conducted for the system model and computer simulation. The important objective of this part of the study is to understand and develop confidence for modelling individual studies in RETScreen Expert software. To accomplish this, RETScreen Expert is used for modeling and simulating the performance of PV systems in several geographical locations, including Fort Wayne, IN. A comparison is made to performance predictions from System Advisory Model (SAM) software. In addition, a study is done to compare predictions from both software to previously published data.In the further phase of the study, eQUEST software, a tool for building energy simulation is used to predict outputs such as electricity consumption, heating loads, and cooling loads for the multifamily residential building considered in this study. These outputs, as well as, building parameters are used as inputs to RETScreen Expert. Since, this study focuses on modeling and simulating the heating and cooling systems coupled with PV for feasibility analysis, only a few minor modifications to the eQUEST default settings are made.The outputs from eQUEST are used as inputs to RETScreen Expert and analysis of ASHP and GSHP systems, as well as their combination with a PV system are performed. The results include the technical performance and financial model of each system, which can be used to indicate feasibility. The results show that both GSHP and ASHP systems are environmentally friendly and reduce energy consumption. These systems are economically feasible, with payback periods of under 10 years, when electricity prices are high. When combined technology is preferred, PV-GSHP systems are more environmentally friendly and have fuel savings far better than any other proposed systems. But the feasibility of the both the GSHP and PV-GSHP systems strongly depends on loop installation cost.