Table 10 shows the average testing results of the 2-stage vapor
compression heat pump combining with the geothermal drying room.
It could be found that hot spring temperatures entering and leaving at
the evaporator are around 44.80°C and 37.60°C, respectively, and heat
capacity of hot spring is around 6.52 kW. While, the heat pump system
could be upgraded heat to be hot water temperature around 84.10°C at
the useful heat capacity and the EER of heat pump 20.67 kW and 4.17
kWth/kWe, respectively. The drying room efficiency in term of EER is
around 2.57 kWth/kWe. For economic results, the investment costs of
the drying room and the 2-stage VCHP are 25,000 USD and the cost
of electrical power consumption is around 1,000 USD/y with 15 sets
of drying per month, 24 hours per drying set. While the revenue from
the geothermal drying room is around 10,500 USD/y, thus the payback
period is around 29 months.