Two DACHS mini-CHP units from Baxi SenerTec UK are providing heat and power for a new centre for health and wellbeing in Southport, north-west England. The units, each producing 12.5 kW of heating and 5.5 kW of electricity, are supplemented by a 750 litre buffer vessel and two exhaust flue gas condensers to boost their heating output by 3 kW each – giving a total output of 31 kW of heat and 11 kW of electricity.
The system is also coupled with two gas condensing boilers which, in conjunction with the CHP units, feed a condensing plate heat exchanger to produce domestic hot water.
The DACHS engine offers an overall fuel efficiency between 79 and 92%, says Baxi, and includes an integrated modem for off-site monitoring and control. Up to 10 units can be installed in a multi-module arrangement. The packaged unit is designed for continuous running with a design life of around 80,000 running hours. The internal combustion engine drives a low-maintenance three-phase electrical generator, and the heat generated by the engine is captured and transferred to the building’s heating system.
Mark Walker, an associate at consulting engineers Hulley and Kirkwood, said the DACHS units had made a significant contribution to the low carbon strategy of the building. ‘We originally considered installing a single larger unit, but this would have been less cost-effective and unable to fit into the plant room, he said. ‘However, the DACHS units offer high heat and power outputs in a small footprint.’