Direct Fired Heaters
Propane direct fired heaters have an open flame that provides a safe way to heat industrial and commercial areas by maintaining a proper air-to-fuel ratio. In a direct fired heater, the gas is fed directly to the burner while the airstream provides the needed oxygen for combustion. Air is forced through the burner baffle where it mixes with the gas.
Direct Fired Benefits
Efficiency – As nearly 100% of the fuel is being converted to heat,
fuel consumption and operating costs are reduced. These heaters are 100% combustion efficient with an overall thermal efficiency of 92% (8% heat loss due to water formation during combustion).
Smaller Size – A direct fired burner can produce more heat in a smaller package compared to an indirect fired burner. This results in an overall smaller equipment footprint in most cases.
Flexibility – Direct fired heaters have much higher turndown ratios than indirect fired heaters, resulting in a greater ability to vary the heat output.
Simplicity – As a heat exchanger and flue are not required, maintenance costs will be decreased.
Equipment life expectancy is longer than indirect fired heaters.
Temperature control is more precise compared to indirect fired
Direct Fired Disadvantages
• Combustion By-Products – Although these heaters operate within
code prescribed safety limits, due to combustion products entering the airstream, proper ventilation is required to avoid buildup of gases such as carbon monoxide.