Heat recovery: Waste not, want not
August 12th 2011 Industrial electricity prices have reportedly risen by 54% in the past five years*. Coupled with the continuing economic malaise, reducing costs and running a lean business has never been so important. Mark Whitmore, general manager at Boge discusses the advantages of waste heat recovery when it comes to optimising energy usage
Operating an energy efficient compressed air system is one area where businesses can expediently turnaround significant cost savings and there are a number of avenues to explore – from installing a frequency controlled screw compressor to incorporating an energy management system. One option that provides an energy saving opportunity for many compressed air users is waste heat recovery.
Almost the entire energy consumption from the supply net of a standard compressor is converted into heat. Taking the example of an oil lubricated screw compressor, up to 94% of the input electrical energy is available for heat recovery. The waste heat generated by the compressor can be re-directed into heating spaces. This form of heat recovery is suitable where the compressor is within the vicinity of the area being heated, for example in a workshop where the compressor is stationed or by the use of ducting, where the compressor is in a more remote location.
It is also possible to extract waste heat from the compressor to heat water for use in central heating or boiler systems, industrial cleaning processes, plating operations, heat pumps, laundries, or any other application where hot water is required.
Before investing in heat recovery, the end user can calculate the potential energy and cost savings of implementing heat recovery by assessing the heat or hot water demand in areas where practical, adjacent to the compressor installation. This assessment should be compared to the average operating hours of the existing compressed air system, which will highlight possible payback in terms of the immediate reductions in fuel, oil and gas costs.
Re-directing the heat generated by a compressor for heating spaces or heating water are options which can assist the end user significantly reduce their associated energy bills and optimise compressor use.
Developing energy efficient compressed air solutions remains a core mission at Boge. The growing popularity of heat recovery has led to the recent extension of the Duotherm heat recovery product range.
Launched at Hannover Fair this year, Boge introduced an external, stand-alone version that can recover up to 94% of the input energy used in compression in the form of heat.The new module is compact, requiring only a minimum space requirement. It connects into the oil circuit of the compressor with no external energy required for operation. As an external hot water heat recovery system the Duotherm is suitable if the compressed air user wants to retrofit heat recovery to an existing compressed air system. It is universal and can be used with any make of rotary screw compressor.”
*Department of Energy & Climate Change (March 2011) Quarterly Energy Prices More articles from Boge Compressors Ltd: | 
