Ground Source Heat Pump Modeling, Operation, and Participation in Electricity Markets

Over the last decades, Ground Source Heat Pump (GSHP) systems have grown in popularity and acceptance worldwide, having the potential to bring about significant benefits, especially if these systems participate in electricity markets through a load aggregator to optimize their operations and provide services such as load shifting and demand reduction, as proposed here. In this context, GSHP systems can be considered as an economically viable and attractive alternative to existing Heating Ventilation and Air Conditioning (HVAC) systems for space heating/cooling in buildings and houses from an aggregator point of view. Hence, this paper presents a detailed mathematical model for a GSHP with a vertical U-pipe Ground Heat eXchanger (GHX) configuration to provide residential space heating/cooling, integrating several such GSHPs into a load aggregator model. Then, a two-stage operational strategy for the GSHP price-taker aggregator participating in day-ahead and real-time electricity markets is proposed, to determine the optimal annual heating/cooling load dispatch to control the temperatures for a community of houses that minimizes the aggregator’s cost. Detailed numerical studies and comparisons with HVAC systems are carried out to demonstrate the feasibility and benefits of the proposed aggregated operation of GSHPs in electricity markets.

I. Introduction

The total residential energy use in 2016 in Canada was 1458 PJ, of which 60% was used for space heating and cooling applications [1]. This energy is mainly supplied by electric and natural gas Heating Ventilation and Air Conditioning (HVAC) systems which add to Green House Gas (GHG) emissions. Hence, there is a need for alternative, low cost, and more efficient clean energy sources for residential and commercial heating/cooling. In this context, the development, application, and market participation of Ground Source Heat Pump (GSHP) systems could play a significant role. However, for these systems to have an impact on the grid and its associated markets, aggregation through agents, typically referred to as a load aggregators, is a good option to add flexibility to electricity markets [2], since individual customer GSHP systems are too small and not eligible to participate in wholesale electricity markets.