Development of a numerical Platform for the Optimization of Borehole Heat Exchanger Fields

Abstract

The optimization of heat pumps on borehole heat exchanger fields is a complex process. Several sizing methods and pieces of software have been acknowledged by the ground-sourced heat pump community (e.g. EED, EWS, ASHRAE method, etc.), though they do not always allow a fine tuning of the system parameters. This paper gives an overview of a numerical platform that allows optimizing the power delivered by the heat pump, the complementary sources (such as gas boilers), the number, depth and positions of boreholes. An algorithm for the optimization of borehole locations intends to mitigate the long term temperature drift due to thermal unbalances and/or take advantage of seasonally stored thermal energy. The user can define several, often competing, criteria for optimization, such as the minimization of a production cost and the maximisation of system performances. Electricity and gas consumption are derived from an hourly dynamic simulation and valorised along with investment costs, which allows the construction of a set of equally optimal solutions known as Pareto front. An example illustrates the output of the platform.