Page 175 - Low Temperature Energy Systems with Applications of Renewable Energy

Heat pumps in the drying industry 165

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1 6

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Fig. 4.31 EBAC heat-pump dryer with air intake and outlet on the side of the drying line:
1 e electric heater; 2 e HP evaporator; 3 e HP condenser; 4 e HP compressor; 5 e
control latch; 6 ehumidifier; 7 e intake valve/channel for fresh air; 8 e exhaust valve/
channel; 9 e wood stack.

Particular attention is paid to the issues of environmental safety of HPD operation.
In Ref. [54] an estimate was made of the effect of greenhouse gas (GHG) emissions for
a specific HPD of plank timber in comparison with traditional heat supply methods
(Fig. 4.32). The horizontal axis shows the drying plant using various fuels. However,
the electricity that is used in the dryers may be received from power plants that burn
solid fuel (left half of the figure), or that burn gaseous fuel (right side). Therefore,

Fig. 4.32 GHG emissions for three different types of drying plants [55].