UK: ammonia system cuts energy use in brewery

A Yorkshire Heineken brewery has implemented a new ammonia refrigeration system, designed by J&E Hall to operate with the existing monopropylene glycol secondary loop. The new plant has reduced the electricity bill by a third, generated significant savings in repair and maintenance costs and reduced the carbon footprint by 2000 tonnes of CO2 per year.
The previous system included 8 independent reciprocating and screw compressors. Replacing them by one common system was a sounder and cheaper solution. The new ammonia system comprised inverter control, allowing for better part-load efficiency. COP, which once was previously 2.5 to 2.8, regularly achieves 5.5 and the maximum cooling capacity of the new system reaches 5100 kW: the normal maximum capacity is 4200 kW with the average being 3600 kW. Five screw compressors now run the cooling system, within which 2 existing compressors were retained. They are linked to a thermosiphon surge drum package allowing the refrigerant to circulate without a pump. The system also includes enhanced plate heat exchangers, new evaporative condensers and a new high-pressure receiver.