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Heat pumps in the drying industry 161

Fig. 4.29 Diagram of HPD with a grain cooling module. C hp , HP condenser; E vhp ,HP
evaporator.

pumps at present is their use for heat supply in wood and timber drying processes that
will be discussed below.

4.4 Wood drying with heat pumps

The worldwide total round wood timber production reached more than
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3,797 10 m in 2017 (Table 4.4), of which about 485.1 10 m was sawn
wood from both conifers and non-conifers (Table 4.5). Round wood production has
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been growing at roughly 43 10 m per year for the last decade. About 58% of
the sawn wood planking is made in the top five countries, China, U.S., Canada, Russia
and Germany [44].
Table 4.4 Round wood production in the top ten countries in 2017 and the worldwide trend
from 2008 to 2017 [44].
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Country 10 m 3 % Total Year 10 m 3
Year 2017 World totals
USA 419.6 11.05 2008 3463.7
India 354.0 9.32 2009 3359.5
China 327.7 8.63 2010 3544.4
Brazil 256.8 6.76 2011 3609.7
Russia 212.4 5.59 2012 3638.4
Canada 155.1 4.08 2013 3686.5
Indonesia 118.3 3.12 2014 3720.6
Ethiopia 113.6 2.99 2015 3711.8
DRC 89.2 2.35 2016 3776.1
Nigeria 75.9 2.00 2017 3797.1