Ground-source heat pump simulation within a whole-building analysis

This paper explores the integration of an algorithm for the simulation of ground-source heat pump systems into a whole-building energy analysis program. GS2000™ is a software program released in 1995 for the sizing of ground source heat pump ground heat exchangers (also known as earth energy systems, geothermal heat pumps, and Geo- exchange systems) (Morrison, 1997). GS2000™ performs the ground loop heat transfer calculation, but requires the monthly building loads – as calculated by an energy simulation program. As the building load is dependent on the size of the ground loop and vice versa, the aim of this project is to incorporate the ground loop algorithms into the ESP-r/HOT3000 engine. Development of the ESP-r/HOT3000 simulation engine is based upon the comprehensive and extensively validated simulation program, ESP-r (ESRU 2000). ESP-r has an extensible structure whereby models and algorithms can be easily incorporated. Modifying the GS2000™ ground heat transfer algorithm, developing the water-source heat pump model accounting for part-load capacity, defining the heat pump COP/EER as a function of entering water temperature including cycling effects, as well as testing and validation will be examined. This paper presents an account from a recent on- going software development project and examines the specific case of incorporating a ground-source heat pump model into ESP-r/HOT3000.