Duncan Edwards Court, a single-storey elderly residents complex in Manchester, UK, relied on three non-condensing boilers the performance of which progressively diminished over time. The eleven-room residential care home’s energy bills also increased incrementally year on year. To rectify the energy issues and moderate the ever-increasing bills, Ground Heat proposed a Vaillant integrated renewable system consisting of an auroTHERM solar thermal array on the building’s roof and two 22 kW geoTHERM ground source heat pumps. Our engineers also installed an ecoTEC Plus 438 boiler as a backup. This also ensures that the system is pasteurised weekly by raising the temperature from 56°C to 65°C for an hour. In addition to the new boiler system, we removed all domestic hot water cylinders from the apartments and replaced them with a communal store of 300 L, thereby reducing the stored capacity by 700 L. We also fitted a simple secondary hot water circuit throughout the building.
On-site monitoring and massive savings
Ground Heat engineers installed sensors in each apartment that have two benefits: they measure the room’s temperature and feed the data to a central monitoring system, and they negate the need for costly call-outs. A series of new radiators were fitted, the first serial feed radiators in the UK, which independent research suggests will provide about a 10.5% energy cost saving. The system is the first of its kind in North West England and the first ground source district heating system accepted by the Community Energy Saving Programme for funding through Scottish Power.
On analysing the monitoring data from the periodic meter readings, we noted that, when the installation is operating, it is deriving substantial benefit from the heat extracted from the boreholes. The ground source heat pump providing the heating shows a low monitored energy use of 8 to 16 kW per day, with a coefficient of performance of 2.60 to 2.9. The ground source heat pump providing the hot water shows a very low monitored energy use of 1 to 3 kW per day with a coefficient of performance of 1.4 to 2.5. The amount of heat generated in the previous year was 300,000 kW. Because of the energy efficiency alterations made to the system, including removing the individual cylinders and fitting a communal store, we estimate that the building will require 240,000 kW of heat. In monetary terms, this equates to a substantial annual saving of £5400. At the 2013 National Heat Pump Awards, Ground Heat won the Commercial Ground Source Installation of the Year award.