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NORA Oilheat Technicians Manual

conserving heating oil if the old boiler or furnace is suitable. Expected energy savings Most homeowners with older oilburners can reduce their fuel cost substantially, with savings from 15% to as high as 25%. The combination of low burner cost and high fuel savings make retention head burners one of the best conservation investments available to homeowners. Your service department can also benefit. New burners usually require fewer service calls. Chapter 16 Energy Conservation Note: AFUE, Annual Fuel Utilization Efficiency, is a US Department of Energy standard efficiency of heating appliances. AFUE ratings are used to compare the efficiency of different makes and models of Replacement of boilers or furnaces Many older heating units are inefficient and oversized and replacement with a new oil-fired boiler or a furnace is better than any add-on modification. New high efficiency oil boilers and furnaces have Annual Fuel Utilization Efficiencies (AFUE’s) from 82% to 95%. Replacing old and outdated heating units will cut fuel consumption and increase customer satisfaction. No simple method can evaluate the efficiencies of older units. However, some design features of older systems tend to increase heat loss and lower efficiency. Some of these are: Designs that allow substantial jacket heat loss by: • Dry-base combustion chamber • Poor or missing jacket insulation • Side arm hot water coils • Massive combustion chambers constructed of heavy firebrick • Many older burner designs use “open” end cones that cannot restrict off-cycle airflow. Secondary air openings and leaks increase off-cycle heat loss. • High stack temperatures increase oncycle heat loss. This is caused by wide open flue passages without baffling designed for burning coal. If the stack temperature is excessive for a clean unit with the correct firing rate and burner adjustment, then the design of the boiler or furnace is the problem. Combustion efficiency testing can help to identify low efficiency boilers and furnaces that need to be replaced. Expected energy savings Replacement of obsolete boilers and furnaces with modern, highly efficient models can reduce fuel cost more than any other single option available to homeowners, even insulation and storm windows. Field studies show that replacing a boiler or furnace will often save between 18 to 32%, with typical payback periods of 3 to 6 years. Pipe and duct insulation Hot water pipes and warm air ducts often waste large amounts of energy when not insulated. These losses reduce system efficiency and increase fuel consumption. Pipe and duct loss is avoidable with the use of thermal insulation. All heating system distribution lines that run through unheated spaces should be protected against heat loss. Boiler pipes The heat loss from this piping system depends upon several factors: • Temperatures of the hot water or steam within the pipes for measuring the furnaces and boilers. 16-14 Energy Conservation


NORA Oilheat Technicians Manual
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