Furnace uses wood byproduct | Despite a major capital investment for the furnace and broiler, it is cheaper than natural gas
CHILLIWACK, B.C. — Installing a wood burning furnace may seem like a step back in time, but there is nothing old-fashioned about Green Valley Produce, a family owned greenhouse operation south of Chilliwack, B.C.
The 15 acres of greenhouses are heated almost entirely by a wood burning boiler with substantial energy savings since it was installed in 2005.
“It definitely was a worthwhile venture. It is a lot more mechanical than a gas boiler because you just put on the computer and it does everything. It takes a little more maintenance and babysitting,” said co-owner Armand Vander Meulen.
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He and his brother, Peter, have a major pepper operation where they sell produce all over North America year round.
Heating the greenhouses and creating carbon dioxide to enrich the atmosphere are major costs.
Prior to installing the wood burning system, they spent about $300,000 a year on natural gas.
Their highest bill was $600,000 when the gas market soared. Last year, they spent $150,000 on gas.
Burning wood had a bad image from past experiences but this system burns clean and there is little residual ash.
The black ash fills a dumpster once a week and gets added to the farm compost pile.
“Until about 10 years ago, the machinery they were using was messy and polluting. With the new European technology, there is just no comparison,” he said.
The furnace and boiler are enclosed in a large structure beside the greenhouses.
It is an automatic system with sensors and conveyors to deliver the wood to a burning box. A hydraulic ram pushes the wood into the boiler bed to heat the water to heat the houses.
A computer controls the fan speed and delivers oxygen so it burns as cleanly as possible.
“The capital investment is much, much higher than gas but the operating side is so much lower that it justifies it,” he said.
Natural gas is burned from May to September to enrich the greenhouse. It still produces heat and that is diverted to water tanks to warm the facility at night.
Two natural gas units with fans draw the carbon dioxide and water vapour off the boiler. It is then circulated through plastic tubes with tiny holes that release gas to the plants.
They burn mostly wood waste from surrounding sawmills processing cedar. The wood is delivered as needed and they only pay the freight costs. It is then mulched and stored in a three-sided shed.
The waste would be thrown into a landfill if it were not used for energy.
“The public thinks we are cutting down trees in the forest but all we do is take secondary byproduct,” Vander Meulen said.
They have used some mountain pine beetle damaged wood from Princeton. It burns well but the freight costs are higher and it is less feasible. Demolition wood is also available from construction sites.
About 10 of his colleagues in the Fraser Valley are using this system.
They bought the system from Western Bioheat, which supplies Austrian built boilers.
Burning agricultural and timber waste is more common in Europe to heat homes, offices, public buildings and industrial facilities, said company spokesman Herb Fieschl.
“We are not inventing the wheel here. It has been going on in Europe for the last 25 years. It is just coming back to Canada,” he said.
The systems can burn mulch like the Vander Meulens use, wood pellets or pellets made from flax or hemp straw.
Grain straw is not as useful because of the low melting point.
“Agro fuels are usually grown with fertilizer and some of the fertilizer goes back into the plants. When you burn these straws, the leftover fertilizer in the straw produces chloride that corrodes your heat exchanger,” Fieschl said.
“The hotter you can burn your biofuels within a certain range, the more efficient they are in their combustion and you don’t have the chlorides,” he said.
These systems are not recommended for generating electricity because they are not as cost efficient as current methods.
