Microsoft Word 2012, Källén, M.,-Energy Efficiency Opportunities within the Heat Treatment Industry

5.3.4  Compressor 

The inlet to the compressor is situated in the compressor room. If the inlet was moved 

outdoors, electricity could be saved due to the lower inlet temperature. The average room 

temperature was assumed to be 20°C and the average outdoor temperature was assumed to be 

8°C. A 12°C lower inlet temperature would give 4% lower electricity consumption in the 

compressor. [19] This would save 15.6 MWh/year of electricity. 

Approximately 85% of the electricity consumption of a compressor will be transformed into 

waste heat. [19] There is currently no waste heat recovery in the compressor. The electricity 

consumption of the compressor would be 368.2 MWh/year instead of 488 MWh/year, if the 

compressed air system was searched for leaks and those were fixed and the inlet was moved 

outdoors. It would then generate 328.3 MWh/year of waste heat. This heat could for example 

replace the district heating that is used to heat the offices and the tap water, since the cooling 

circuit in the compressor has a high enough temperature. This would save 120 MWh/year of 

district heating and there would be no need to buy district heating. 

It would be desirable to use the remaining waste heat in the process. One alternative is to heat 

the water in one wash with waste heat from the compressor. This could however be difficult 

to achieve in reality since the washes are located far from the compressor room. The 

investment was considered to be too complicated to be further investigated. 

 

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