Vegetable growers dig deep to improve greenhouse energy efficiency
A recent research and development project, which features in the latest edition of AUSVEG publication Vegenotes, has examined the potential to harness solar energy stored in the top layer of the earth’s surface to warm vegetable-growing greenhouses, through a process known as geothermal heat pumping (GHP). “The technology involved in geothermal heat pumping is very exciting and could revolutionise the way the industry cultivates vegetables, in a manner which is both effective and environmentally friendly,” said AUSVEG spokesperson, Michael Bodnarcuk.
AUSVEG is Australia’s leading horticultural body representing 9,000 vegetable and potato growers.
GHP technology works by drawing heat from the ground with a long loop of water-filled pipes, which are buried a few meters deep in the soil. As water flows through the underground pipes, it is warmed by heat retained in the Earth from solar energy. The pipes then run through the greenhouse, regulating the temperature inside.
“This allows greenhouses to stay at a constant temperature without the need to continually run conventional, and wasteful, heating systems,” said Mr Bodnarcuk.
“In Europe and the USA, heat pumping has been used for decades as a conventional heating method. The system essentially acts as a reverse refrigerator, with the main exception being that it harnesses only natural and clean energy from heat stored in the ground,” said Mr Bodnarcuk.
One main benefit of GHP can be seen in the carbon efficiency of the technology. Initial results from the project have found that, as well as providing clean energy, GHP also maintains excellent vegetable growth performance figures.
The project, led by Jeremy Badgery-Parker, was funded by HAL using the National Vegetable Levy, voluntary contributions from industry and matched funds from the Australian Government.
“Through the use of geothermal heat pumping, greenhouses have been successful in maintaining steady temperatures of 18 degrees, an ideal temperature for stimulating vegetable growth. As well as maintaining this temperature, for every kilowatt of electricity input into GHP, 4 kilowatts of heat energy are supplied back to the greenhouse, which is a very efficient rate of return,” said Mr Bodnarcuk.
Greenhouses have traditionally operated using gas-heated systems, however, the concerns associated with carbon emissions have increased the cost of energy, encouraging growers to examine alternative heating systems for their greenhouses.
“As the price of conventional fuels is continually rising, it is especially important that the vegetable industry considers alternate energy sources,” said Mr Bodnarcuk.
This communication has been funded by HAL using the National Vegetable Levy with matched funds from the Australian Government.
MEDIA CONTACT: Michael Bodnarcuk, Communications Officer, AUSVEG. Mob: 0400 114 266 Ph: (03) 9882 0277 Email: firstname.lastname@example.org