Saving with heat recovery US number Home Kiln theory General theory Heat recovery system.

Actual comparison on energy consumption on kilns in Europe (Denmark).

Company: Dansk Trae Emballage Ribe, Denmark.
Drying: 3/4" pine boards used for pallet, crating and other packing solutions.
Background: The company operates five kilns. These kilns have been placed in two groups:

• Kilns with traditional roof type venting
• Kilns with heat recovery system.

Both groups have a KW meter on the heat supply provided as accurate heat usage measurements as possible. In addition, most lumber mills dry a great variety of species and thickness, which make comparison difficult. In this case, the company is drying only one specie and one thickness making for an accurate comparison.
Period of this comparison: January 4th to January 31st, 2001

TABLE 1: Raw numbers collected from Dansk Trae Emballage.
	Boardfeet	KW usage	Energy usage	btu/bf
Traditional kilns:	585120 bf.	239120 Kw	822094000 btu	1405
Heat recovery kilns:	240408 bf.	65580 Kw	225464000 btu	937.8
Savings in percent:				33.3%

TABLE 2: Estimated saving per 100,000 board feet lumber dried per month.
	Boardfeet	Energy usage	US$/mbtu	US$/month
Traditional kilns:	100000 bf.	140500000 btu	US$: 0.0157	US$: 2205.85
Heat recovery kilns:	100000 bf.	93780000 btu	US$: 0.0157	US$: 1472.35
Possible savings				US$: 733.50

Note 1: Based on one gallon of gas costing US$: 1.30 and a boiler
with 90% efficient. (No capital cost included).
The savings from our example are based on comparing older traditional type kilns with the newest technology in heat recovery. The savings in this example may not be obtainable in every situation, but we believe that savings between 15% to 40% is possible depending on your specific situation. We have been able to establish a rule of thumb:

• By upgrading existing kilns and installing a heat recovery systems, you will be able to increase you capacity by about 50% without increasing your heat consumption and boiler capacity.