Multi-criteria optimization for a residential horizontal ground heat exchanger

Abstract

Ground source heat pumps (GSHP) are the most efficient heat pump systems currently in use for residential sector today. Although these systems outperform all other heat pump systems when considering the energy source, the installation costs represent an ongoing issue. For the market to increase in this area, multi-criteria optimization for the ground heat exchanger (GHE) is the main research topic today. The main objective of this study is to search ways to optimize the horizontal ground heat exchanger focusing on two distinct viewpoints: physical and energetic optimization. To achieve this goal, the entropy generation number and the coefficient of performance based on several configuration are studied. Using the Pareto optimal set obtained from two objectives provides useful information about the design optimization. In comparison with traditional single objective optimization, multi-criteria optimization avoids cost increase when regarding only the performance or performance decrease when regarding only the cost. The results indicate that the use of a cheaper heat source such as solar panels to mitigate the energy needed for peak loads during the heating and cooling systems can reduce the horizontal ground heat exchanger size and therefore the installation cost. A hybrid solar assisted ground source heat pump system, using more than one renewable energy source, shows a much higher flexibility for residential purposes than a heat pump system that uses only one renewable energy source.