Mini-CHP achieves large savings for London home
Annual cost savings of over £2000 are expected following the installation of a Dachs mini-CHP unit in a residential property in London. Installed in a garage, together with a condenser and buffer vessel, the unit generates up to 15.5 kW of heat, which feeds into a 750 l buffer vessel connected to the heating circuit, also served by two condensing boilers. The circuit serves space heating for this substantial Victorian detached house and indoor swimming pool in an extension, which provides a constant demand for heat.
The heating system was designed by consulting engineers Michael Popper Associates, and its installation was overseen by technical-support staff from Baxi-SenerTec UK.
Power generated by the Dachs unit is used to supply household demand and displace electricity from the grid. Dachs gas-fired units have an electrical output of 5.5 kW and a minimum heat output of 12.5 kW, or up to 15.5 kW using a condenser.
Over seven months from October 2010 the unit generated 143 MWh of heat and 26 MWh of electricity.
Paul Brookes, technical manager for Baxi-SenerTec UK, comments, ‘Calculating cost savings hasn’t been entirely straightforward, due to a rise in fuel costs and change in running conditions since the system was first installed. Now that the unit is running 24 hours per day and based on the latest fuel tariff, new annual savings are projected to be in the region of £2048 — a figure that can only increase year on year given the constant upward movement in fuel prices.’
