The efficiency of boilers and air heaters can vary from below 503 to more than 803. Improvement by even 53 could mean a very substantial annual economy. Heat losses from boilers and air heaters occur mainly due to the flue gases being discharged at a higher temperature than the air used for combustion. While combustion losses cannot be eliminated, they can be reduced to a minimum by: a) reducing the amount of air supplied to the minimum for complete fuel combustion, and b) ensuring that the optimum amount of heat is transferred from the flue gasses as they pass through the equipment. In practical terms, this means that the fuel/ air ratio must be accurately controlled and the heat transfer surfaces kept free of soot and scale. One eighth inch of scale can reduce boiler efficiency by l 0 3. A permanently installed flue-gas thermometer will give early warning of the need to clean soot and scale, and possibly show when the burner is out of adjustment. This equipment, together with apparatus to measure CO, in flue gas costs about $120.00. Even on a quarter acre, a modest increase in efficiency of about 33 would allow equipment cost to be recovered. Where the efficiency of the boiler is inherently low, it is wise to assess the economies of replacing it.
Source: • Colorado State Flower Growers Association Bulletin #307
Keywords: Efficient heat