Abstract
A process simulation of industrial heat pump drying of clipfish is performed and the energy consumption for
different systems is compared. The components of the heat pump (evaporator, compressor, 2 condensers,
expansion valve and controller) were dimensioned for a 250 kW (thermal) system and a drying model based
on the similarity between heat and mass transfer is used to develop a batch tunnel drying model. The
investigation was performed with the natural refrigerant Ammonia (R717). The energy consumption for heat
pump drying was simulated to be 222.6 kWh per ton of produced clipfish compared to 973.8 kWh per ton of
clipfish for a drying system using heated ambient air. The moisture profile through the tunnel is significant
and is a limitation for industrial batch tunnel driers. Measures to increase process efficiency are discussed by
means of energy consumption, specific dehydration rate and heat flows. A new drying concept is proposed,
using the excess energy of the secondary condenser for a final drying period in storage facilities. Using the
same dimensions of the heat pump it was possible to increase the productivity of the heat pump drier by
40%, while at the same time the production costs were decreased to 133.6 kWh per ton of clipfish. Also the
moisture profile through the batch tunnel drier is minimized by the proposed system. Copyright © 2014 IIR/IIF. All rights reserved.
different systems is compared. The components of the heat pump (evaporator, compressor, 2 condensers,
expansion valve and controller) were dimensioned for a 250 kW (thermal) system and a drying model based
on the similarity between heat and mass transfer is used to develop a batch tunnel drying model. The
investigation was performed with the natural refrigerant Ammonia (R717). The energy consumption for heat
pump drying was simulated to be 222.6 kWh per ton of produced clipfish compared to 973.8 kWh per ton of
clipfish for a drying system using heated ambient air. The moisture profile through the tunnel is significant
and is a limitation for industrial batch tunnel driers. Measures to increase process efficiency are discussed by
means of energy consumption, specific dehydration rate and heat flows. A new drying concept is proposed,
using the excess energy of the secondary condenser for a final drying period in storage facilities. Using the
same dimensions of the heat pump it was possible to increase the productivity of the heat pump drier by
40%, while at the same time the production costs were decreased to 133.6 kWh per ton of clipfish. Also the
moisture profile through the batch tunnel drier is minimized by the proposed system. Copyright © 2014 IIR/IIF. All rights reserved.