Efficient Technologies

Lumber and Wood Industry

Main applications and potential benefits

Dehumidification

Heat pump with electric preheating

Low-temperature drying process using a drying cell equipped with an electric preheating device and a heat pump that dehumidifies the air, recovers heat, and transmits it to the drying cell.
Applications	Benefits
Drying processes: Hardwoods 2 in. thick or less (including white pine) Softwoods 3 in. thick or less	Very high quality (original color, little or no checks or warping) Relatively low purchase price (approximately $3,500/1,000 bd. ft.) and installation cost Allows for variations in drying cell capacity Energy consumption at least 2 to 3 times less than that of conventional processes with similar drying cycles (0.8-1 kWh per kilogram of water evaporated, compared with 1.5-2.3 kWh/kg) Fire insurance costs 30% to 50% lower than conventional drying

Low-temperature drying process using a drying cell equipped with an electric preheating device and a heat pump that dehumidifies the air, recovers heat, and transmits it to the drying cell.

Applications

Benefits

Drying processes:

Hardwoods 2 in. thick or less
(including white pine)
Softwoods 3 in. thick or less

Very high quality (original color, little or no checks or warping)
Relatively low purchase price (approximately $3,500/1,000 bd. ft.) and installation cost
Allows for variations in drying cell capacity
Energy consumption at least 2 to 3 times less than that of conventional processes with similar drying cycles (0.8-1 kWh per kilogram of water evaporated, compared with 1.5-2.3 kWh/kg)
Fire insurance costs 30% to 50% lower than conventional drying

Heat pump with fuel-fired preheating

Applications	Avantages
Low-temperature drying process using a conventional fuel-fired preheating system (accounting for approximately 15% of the total energy requirement) and a heat pump that dehumidifies the air, recovers heat, and transmits it to the drying cell.
Drying processes: Hardwoods 2 in. thick or less (including white pine) Softwoods 3 in. thick or less	Very high quality (original wood color, little or no checks or warping, no mold) Relatively low purchase price ($4,000/1,000 bd. ft.) Use of low-temperature kilns, more economical to purchase, operate and maintain than conventional kilns Drying time comparable to high-temperature kilns Optimization of drying equipment possible without adding a boiler

Vacuum

Heating plates and resistances (heating blankets)

Applications	Benefits
Process whereby the wood is stacked between metal plates or heating blankets in which hot water circulates.
Drying processes: Hardwoods and softwoods up to 3 in. thick Particularly suitable for light-colored wood Short pieces for furniture or flooring	Very high quality (original wood color, little or no checks, no warping) Suitable for small production volumes (kiln capacity of 500, 1,000 or 2,500 bd. ft.) Process 3 to 7 times faster than conventional drying Low energy consumption (approximately 0.8 kWh per kilogram of water evaporated)

High frequency (radio frequency)

Process in which wood is stacked between metal plates in a vacuum chamber and heated by high-frequency waves that interact with the water content in the wood.
Applications	Benefits
Drying processes: Hardwoods and softwoods over 2 in. thick (no limit) Drying of solidly stacked pieces for furniture, flooring and decorative items Particularly suitable for light-colored wood	Excellent quality (original wood color, little or no checks or warping) Drying speed 8 to 15 times faster than conventional drying Combined drying of short and long pieces; no spacers required Quick drying of very thick pieces (less than 6 days for 24-in. pieces) Satisfactory energy consumption (approximately 1.3 kWh per kilogram of water evaporated) No need for equalizing or conditioning at the end of the drying cycle

Process in which wood is stacked between metal plates in a vacuum chamber and heated by high-frequency waves that interact with the water content in the wood.

Applications

Benefits

Drying processes:

Hardwoods and softwoods over 2 in. thick (no limit)
Drying of solidly stacked pieces for furniture, flooring and decorative items
Particularly suitable for light-colored wood

Excellent quality (original wood color, little or no checks or warping)
Drying speed 8 to 15 times faster than conventional drying
Combined drying of short and long pieces; no spacers required
Quick drying of very thick pieces (less than 6 days for 24-in. pieces)
Satisfactory energy consumption (approximately 1.3 kWh per kilogram of water evaporated)
No need for equalizing or conditioning at the end of the drying cycle