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GREENHOUSE
CANADA Alberta company's heating system features a mix of old and new technologies. An Alberta company thinks growers should consider 'coal' when battling the cold. Nova Metal Tech Ltd. says its heating system is a mix of old and new technology. The All Canadian coal-fired Hydronic Heater has an 18 year history, but some of the technology used, especially in the fire stoker unit has been around since the 1940s. In sizes from 300,000 BTUs (for a hobby sized greenhouse) to 2.3 million BTUs, the coal-fired heating units employs an after-burner, which increases the efficiency of coal by up to 40 per cent by burning gases that would normally just escape into the atmosphere. As far as environmental impact, Ernie Belanger, a company spokesperson, said to date there is no governmental emission restrictions on these units in Alberta, but that the company is planning to contact the Alberta Research Council to monitor the stack emissions for more definitive data. Belanger said the advantages to switching to coal, especially from natural gas, is in the price. The price of coal, according to the company, is about 30 per cent of the cost of gas per BTU. "In North America over the past century, coal has been replaced by other forms of fuel like natural gas," he said. But recent energy price hikes may cause more growers to consider alternatives, including coal. The company has had a 1.5 million BTU furnace at an Edmonton-area greenhouse since 1982. This unit has been operating approximately seven months out of every year since then without being shut down. "Since 1982 our heaters have been installed in many other greenhouses as well as in various other agricultural applications," said Belanger. "Our heaters have proven themselves to be durable and dependable." The units have two primary components - the stoker, which pulls coal from a hopper, and a burner. The burner can actually use any pelletized (compressed and shaped) fuel such as wood scrap, straw or sawdust. The units are fully automated and require minimal supervision. The biggest disadvantage when comparing the coal-fired heaters to natural gas systems is the wear on the feeders in the coal system. Coal is an abrasive substance, so there is constant wear on the mechanical components. Other drawbacks, according to Belanger, are the need for suitable storage facilities for the coal, and the minimal amount of dust, or fly ash, produced by the burner. Another difficulty is the availability of fuel. While the east coast and the western provinces have large available supplies of coal, the supply in southwestern Ontario is much more limited. Belanger said that the farther a combustible product had to be shipped, the more costly the end price.
Trevelles Contracting Ltd. RR#2, Site 3, Box 9, Kingman, AB T0B 2M0 |