Two Dachs mini-CHP units from Baxi-SenerTec UK are providing heat and power for the new £5 million Southport Centre for Health and Wellbeing.
The units, each producing 12.5kW of heating and 5.5kW of electricity, are supplemented by a 750-litre buffer vessel and two exhaust flue gas condensers to boost their heating output by 3kW each giving a total output of 31kW of heat and 11kW 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.
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.
“Space was the major challenge on this project along with noise levels and minimising the carbon intensity of the building. We thermally modelled the building and designed it in such a way that we didn’t need to employ renewables.”
The Dachs packaged mini-CHP unit is designed for continuous running with a design life of around 80,000 running hours. The reliable 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.
“The Dachs has much lower noise levels than larger systems – down to 52 dB(a) at 1m,” added Mr Walker. “This meant we could easily meet local planning restrictions covering noise pollution. These units are particularly good for building up capacities in a modular way and they have proved themselves to be a cost-effective solution to reducing the carbon footprint of small buildings.”
The Dachs engine offers an overall fuel efficiency between 79 and 92% and includes an integrated modem for off-site monitoring and control. Up to 10 units can be installed in a multi-module arrangement.
The 15-month building project was completed on time and to budget under the Local Improvement Finance Trust scheme (LIFT), a vehicle run by Liverpool and Sefton Health Partnership to improve and develop frontline primary and community care facilities in the area. The M&E element of the project was worth around £900,000.
The NHS LIFT scheme is a Government initiative designed to stimulate investment in local primary and social care facilities. To date 96 new centres have been delivered nationally across England under the initiative.