Boilers and mini-CHP module deliver low-carbon solution
Baxi Commercial Division has supplied Potterton Commercial boilers and Baxi-SenerTec multi-module Dachs mini-CHP system for the refurbishment of the heating system of St Aidan’s College of Durham University. The previous heating system had reached the end of its operational life, and the university was keen to ensure that the replacement equipment should employ low-carbon technologies.
Three mini-CHP units have been installed, each with an electrical output of 5.5 kW. With the help of exhaust-gas condensers, the heat output is up to 15.5 kW per unit. All are connected to a single buffer vessel to even out heat demand.
The CHP system is designed to match the base thermal load to maximise running hours and increase the overall efficiency of the engines by reducing the number of starts per day.
The engines were installed alongside three 440 kW cast-iron boilers. All the equipment was installed in the basement plant room. The flue for the DACHs system required careful integration with the boiler flues and the existing chimney to ensure correct operation.
The boilers for this project were fitted with modulating natural-gas burners and are controlled by the site’s BMS.
Martin Huitson, the university’s senior mechanical-services engineers tells us that in the first year of operation the CHP system achieved 87% of its predicted energy production, despite initial operational bedding-in issues. Output was over 73 MWh of electricity and over 171 MWh of heat.