Temp, control/manipulate Home Kiln theory Basic theory Work of standard kiln (Temp/RH/Airflow)

The temperature can be manipulated through several different heat sources and mechanical controls. Some operate the heat as an ON/OFF system and others as a modulated system. Some heat sources available are:

Steam:
This can be either high or low pressure. A steam valve is frequently used to control the temperature; either through the standard ON/OFF valve or using a modulated valve. Some pneumatic and electric valves offer the inexpensive ON/OFF sequencing modulation. (Note 1).

Hot water:
A valve is normally used to control the temperature; either through the standard ON/OFF valve or using a modulated valve. Some pneumatic and electric valves offer the inexpensive ON/OFF sequencing modulation. (Note 1).

LP Gas, Natural gas, or #2 oil:
This is called a direct heat kiln. Gas is the more common, as it burns cleaner. The biggest disadvantage with direct gas fired kilns is the constant venting required. As the flame needs oxygen to burn, the system will continue to moderately vent when ever the heat source is on. This explains why direct heating is normally used on fast drying species which requiring almost constant venting. However, Kiln-direct has innovated a new implementatio of direct heating using gas. As a result, we have solved the problem of constant venting by utilizing separate combustion chamber. These direct gas fired heating system is 100% efficient and can be installed on small lumber kilns as well. (More information about Kiln-direct direct gas heating system).

Electric:
This in normally a very expensive source of heat. Only areas with very cheap electrical power can be considered. It is a simple system to operate, but most kilns with electrical heat are underpowered.

Note 1:
The steam or hot water can be generated through several different means. The most common fuels are LP or Natural gas, #2 oil, wood waste. Wood waste system are normally only economical on larger systems. We at Wooddryer System believe the fully modulated valve system is an unnecessary extra cost, as we have invented the ON/OFF sequence modulation using standard valves. All our controllers support this feature.