Geothermal Heat Pumps Role in Rebuilding Christchurch’s Commercial Business District

Abstract

In February 2011 Christchurch experienced a destructive earthquake, resulting in the central business district being extensively damaged. Significant rebuilding of the commercial infrastructure has seen megawatt scale geothermal heat pump (GHP) systems installed. Christchurch city overlies a series of confined groundwater aquifers, ranging in depth from less than 13 m to greater than 150 m. The aquifers are productive, with yields in excess of 100 L/s possible from a single well, with ground water temperatures of about 13°C providing an ideal source for energy for facilities heating and cooling. With these physical characteristics, the installation costs of megawatt sized GHP systems can be paid back in under ten years; this being a key driver to the recent increased uptake of this technology. This paper discusses the Christchurch aquifers and the aquifer energy systems, analyses the rate of uptake of the technology, discusses four projects in more detail and identifies two projects that are anticipated to be completed before 2022.