Innovative chiller delivers major reductions in energy consumption
The Turbocor compressor made by Danfoss marked a step change in compressor development and is now incorporated in chillers from several manufacturers. They include the Turbomiser chiller, which is the result of close collaboration between two UK companies, Klima-Therm and Cool-Therm, and Italian manufacturer Geoclima — and which was acclaimed product of the year in the CIBSE Awards.
There are more than 20 installations of Turbocor chillers in the UK, with cooling capacities from 250 to 1000 kW. More are in the pipeline.
At the heart of these chillers is the inverter-controlled Turbocor centrifugal compressor, the output of which can be precisely matched to load — right down to 15% of full load. They have magnetic bearings and are extremely light. A compressor with a cooling capacity of 300 kW weighs just 125 kg, compared with 600 kg for typical screw and reciprocating chillers.
The latest Turbomiser chiller, the Turbomiser II, is said to be 30 to 50% more efficient than systems based on screw, scroll or reciprocating technology. On many applications, the payback on the extra capital cost compared with a chiller using screw-compressor technology can be less than a year.
Turbomiser chillers can operate with a floating head pressure, providing opportunities for energy savings that are not available to conventional designs. A chiller constantly self regulates and optimises its performance in response to ambient conditions and load.
At low ambient temperatures, the compressor can be switched off and refrigerant circulated by a liquid pump using just 1 kW.
The energy-saving potential of Turbomiser chillers are demonstrated by an installation at The Dorchester Hotel in London with a cooling capacity of 3 MW. These air-cooled chillers replaced R22 chillers and cooling towers and have reduced energy costs by £10 000 a month. There are additional savings from their being no need for water treatment and reduced maintenance generally.
The low weight of the chillers enabled them to be installed on rooftops, freeing up the plant room used for the previous chillers.
Tests carried out by Mike Creamer of Business Edge on an operating Turbomiser chiller at Geoclima’s factory in Italy showed COPs of 7 to 15.5 at typical mid-season conditions, with an average performance of 5 to 7. He says, ‘These are excellent results and confirm the positive claims being made for the Turbomiser technology.’
