|Title||Residential Furnace Blower Performance|
|Year of Publication||2006|
|Authors||Iain S Walker|
|Institution||Lawrence Berkeley National Laboratory|
The objective of this study was to assess the performance of furnace blowers and the potential cost-effectiveness of setting performance standards and changing motor technologies.
In this study, a testing program was undertaken at Lawrence Berkeley National Laboratory and the PG&E test laboratory in San Ramon to compare the performance of furnace blowers. Five different combinations of blowers and residential furnaces were tested for air moving performance. The laboratory test results for blower power and air flow were combined with DOE2 models of building loads, models of air conditioner performance1, standby power, as well as igniter and combustion air blower power.
Energy savings and peak demand reductions in this study are based on replacing a Permanent Split Capacitor (PSC) blower, dominant in the market, with a Brushless Permanent Magnet (BPM) blower2. Annual energy savings for a typical three-and-a-half ton air conditioner with typical California ducts are 45 kWh. Peak demand reductions are 50 W per system, or about 0.13 GW statewide if all blowers were replaced. The numbers improve significantly for duct systems that match manufacturers' rating points. For such systems, annual energy savings increase to 153 kWh, and peak demand reductions to 70W per system, or about 0.18 GW statewide when all blowers are replaced. The payback time assuming no utility rebates for typical system is 13.5 years and for an improved system that meets manufacturer's specifications is reduced to 4 years. If fans were operated continuously—for mixing, filtration or ventilation purposes, the potential savings for BPMs improve even more, about 1800 kWh per year and the payback time is less about 4 months.
However, the benefits of the variable speed BPM motors were found to depend strongly on interactions with the rest of the thermal distribution system. The high air flow resistance of typical California duct systems almost eliminates the advantages of the BPM motors. As a result, BPM blowers may not be cost-effective because the potential improvements blower performance are restricted by the static pressures prevalent in residential thermal distribution systems in California.
It is possible to obtain better performance from BPMs and interactions with the rest of the HVAC system were found to be very important. Key areas for improvement include:
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