Thermal Storage Properties of a Hybrid Ground Source Heat Pump.

Hybrid ground source heat pump (HyGSHP) systems are gaining popularity as a means of decreasing long term energy and maintenance costs while maintaining manageable first costs. In these systems there is a potential to use the ground not only as an immediate heat source or sink, but also as an energy store. On a scale of months, heat rejected to the ground during the cooling season could potentially be recovered during the heating season. On a scale of hours, the ground storage could be cooled by a hybrid component, such as a cooling tower, during the night in order to improve the heat rejection efficiency in cooling during the following day. This paper will present the results of a detailed study of the ground as a thermal energy storage medium on a short term basis in a cooling dominated environment, also referred to as night pre-cooling. A simplified model of a bore field is developed to calculate storage efficiency and then a more detailed model is used to evaluate the power consumption and operational cost of a system using the ground for diurnal thermal storage. [ABSTRACT FROM AUTHOR]