“The air inside a greenhouse is actually a mixture of air and water vapour,” explained Novarbo's Jukka Huttunen. “Most of the energy in the air comes in the form of water vapour, especially in a greenhouse, where humidity can reach up to 90 percent.” Novarbo's HumidAway system reduces that humidity and in doing so, harvests the latent energy with the help of a heat pump.
“Half of the energy savings come from not having to open the vents and the other half comes from the energy harvested,” said Huttunen. “The coefficient of performance we can get is quite high, it's somewhere around five-to-seven.” It means the heat harvested heat has a price of 1/6 of the price of electricity. A prototype of the system has been in testing all this year, and Huttunen expects a commercial model will be available next spring. He cited some estimates from growers who reported that up to 40 percent of their energy costs went into climate control, so a way to cut down on those costs, like HumidAway, would certainly be welcome by growers.
Expected dehumidification rate 16 l/h and heat harvesting 16-26 kW.Expected dehumidification rate 16 l/h and heat harvesting 16-26 kW.
The process involves using HumidAway units, 10 or 15 of them per hectare of greenhouse space. Units including fan, special water nozzles, air hose and connections to water tank and heat pump.“We all have the same goal: to save energy and control the climate inside the greenhouse,” said Huttunen. “So we're all racing to reach that goal.”
For more information:
HumidAway
Jukka Huttunen (e-mail)
Novarbo Oy, Biolan Group
+358 44 546 1192
www.novarbo.fi/english/default4.asp?active_page_id=1220