Heat pumps boost the energy efficiency of a Swiss Krono chipboard factory

| Hot water and energy equivalent of 10 MW produced by heat pump technology

Located in the northeast of Germany, the Swiss company Swiss Krono produces chipboards primarily based on wood from surrounding areas. This production process heavily consumes electrical and thermal power sources owing to several energy intensive manufacturing steps. (> 200 GWh electrical and > 1300 GWh thermal). These processes especially include slicing of tree trunks, drying of woodchips, and compacting them to form chipboard.

To minimize energy consumption for the chipboard products, Swiss Krono has implemented a large number of energyreducing measures. One of the primary measures is two GEA Grasso heat pumps to provide hot water with an energy equivalent of 10 MW and at a hot water temperature of 80 °C. Mixed with the 2 MW waste heat from a cogeneration unit, the total of 12 MW for hot water is used to predry the entire amount of wood chips. The energy efficiency of the heat pump solution here becomes more apparent if we consider the energy source for the heat pumps. A company-owned biomass-power plant provides electrical power of 20 MW. The exhaust vapors of the power plant are condensed by two air-cooled condensers.

This energy source was previously ignored. Now, however, the condensate (at 39 °C) is used as the energy source for the two heat pumps. As part of a closed water loop within the biomass-power plant, Swiss Krono installed two heat exchangers to separate the water circuit of the power plant from the water circuit of the heat pump, and to transfer the heat to the source side of the heat pump. Under current conditions, the COP of the heat pumps is 4,5. Pre-drying reduces the moisture content of the wooden chips and saves energy used for the final drying in two rotary dryers. Based on 6,500 operating hours of each of the 2 heat pumps in 2016, an energy equivalent reduction of approximately 32 GWh and a CO2 equivalent reduction of 6700 tons have been achieved.

 

EHPA invites everyone to submerge themselves in the possibilities that heat pumps are capable to offer in several industrial sectors. To read more stories the updated booklet is currently available on EHPA’s website.