Ground source heat pump

While heating demand can be reduced effectively through appropriate measures, the remaining heat demand can be replaced through renewable sources such as Ground Source Heat Pumps (GSHP). A GSHP is a heat pump that uses the Earth as either a heat source or a heat sink. GSHP need very significant loops in order to heat up the ground circuit. Laying loops horizontally is lower cost but impractical for warehousing as the surface area required would typically be over 20 times the footprint of the warehouse. Most industrial applications require 100m boreholes each 5m apart.

A detailed survey is required at each site to evaluate the exact length, shape etc of the ground circuit which can effect costs by +/- 50%. This is because the amount of vertical or horizontal loops required is a function of the ground formation thermal conductivity, deep earth temperature, and heating and cooling power needed, and also depends on the balance between the amount of heat rejected to and absorbed from the ground during the course of the year. GSHPs require electricity to run and their efficiency is measured by a coefficient of performance (COP, usually between 3 and 4) – the ratio of kWh of heating output per kWh of electricity input.