Free cooling of low energy buildings with ground source heat pump system and bidirectional ventilation

Earlier field measurements in Low Energy Buildings have shown that excess temperatures can easily occur during summertime in well-insulated houses, also in northern part of Europe. If a ground source heat pump is used for heating and there is a bidirectional ventilation system, the borehole can be used for free cooling in summertime and the chilled air can be distributed by the ventilation system. In this study, a simulation of a single family nZEB located in the Swedish city Gothenburg was conducted.

Effects of groundwater flow direction on performance of ground heat exchanger borefield in geothermal heat pump systems using 3-D finite difference method

The effects of groundwater direction on performance of geothermal heat pump systems were analyzed using a 3-D finite difference method with rectangular meshes. Each borehole was approximated by a square column with the actual circular borehole section circumscribing the approximated square section. The fluid temperatures inside each borehole were calculated by discretizing borehole vertically into different segments.