Packing firm’s compressor waste heat warms local college 22 May 2014

Greiner Packaging's plant in Northern Ireland is helping a local college to cut its £40,000 annual heating bill by donating waste heat from compressors and its process cooling installation.

Dungannon Integrated College now receives the heat into its central heating system via underground pipework, not only reducing costs but also saving 200 tonnes of CO2 emissions.

Greiner, which specialises in rigid packaging containers for the food industry, uses Atlas Copco oil-free, water-cooled Z-range compressors to generate air for its production processes.

Jonathan Parr, electrical services and plant manager at the site, says that it is the compressors' water cooling systems that provide the waste heat supply.

He explains that air drawn into compressors contains water vapour and that heat stored in the vapour is released through condensation in the units' inter- and aftercoolers – to the tune of 5—20% of the electrical input energy.

This property is exploited by Atlas Copco's Z-range screw compressors, which have energy recovery capability, in the form of hot water, claimed to amount to 80—100% of the electrical input energy, depending on the site conditions.

This supply is combined with hot water derived from cooling fans near the college, which assist the cooling cycle that is integral to the host plant's plastic forming processes.

"The rapid sequence of heating and forming plastic materials requires equally fast cooling of the molten polymers," comments Parr.

"We achieve this with a large battery of condenser cooling fan units, in addition to the water cooling systems on the compressors. [These] extract the heat in the form of hot water at 80C that is then delivered to the school via 275 metres of pipework buried a metre underground," he adds.

The project is estimated to have cost Greiner Packaging £90,000, a sum matched by funding from the Department of Education whose spokesman at the launch event said: "It's a project that shows recycling, it shows an environmental responsibility and it shows social responsibility."

Brian Tinham

Related Companies
Atlas Copco Compressors

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