Ductless Mini-Split Heat Pump for Manufactured Homes
Manufactured Housing Ductless Mini-split Heat Pumps: Variable-Speed Compressors vs. Constant-Speed Compressors
Ductless Mini-Split Heat Pumps with Variable Speed Compressors, but this application is designed specifically for use in multifamily residential applications.
Item ID: 301
Equipment that is capable of operating only as much as needed to meet the load is more efficient than equipment that can only operate at full capacity or off. HVAC split systems, including ductless split systems, include variable speed (inverter-driven) compressors. Constant speed on/off-only compressors are good for locations where the load is constant, such as a small data or server room. However, for most applications, the load changes with the seasons and time of day. For these applications, inverter-driven motors on HVAC compressors can save significant energy.
Variable speed compressors have been available in other countries for many years, commanding more than 80% of the commercial and residential market combined in Japan, Europe, and China. This technology is now available in the U.S. and manufacturers are offering more options to fit the U.S. market.
NEEA conducted a pilot program in 2009, training 900 installers and succeeding in getting 4,000 ductless heat pumps (DHPs) installed. The heat pumps were provided by 5 different manufacturers. By 2011, NEEA indicates that more than 13,000 ductless heat pumps had been installed in the Northwest, savings at least 40,500,000 kWh of energy (3,115 kWh/unit). Research showed that 90% of customers were satisfied with their ductless heat pumps and that customers reported a 25% to 50% reduction in their heating bills.
Baseline Description: Manufactured Home Heating EUI
Baseline Energy Use: 6.9 kWh per year per square foot
Manufacturer's Energy Savings Claims:
Currently no data available.
Best Estimate of Energy Savings:
"Typical" Savings: 33%
Low and High Energy Savings: 25% to 55%
Energy Savings Reliability: 6 - Approved Measure
Per AHRI this ET has IEER's in the high teens to midtwenty's. Existing heat pump equipment is in the low teens. Energy savings will depend on weather conditions for a given site. As the bulk of the energy used is for heating (rather than cooling), a ductless heat pump COP of 3.5 is assumed (Daiken values range from 3.2 to 3.8). This results in a heating and cooling energy savings of about 71% when compared to baseboard electric heating. But, ductless heat pumps typically are defined as a zonal heating source and do not serve the entire household. Geraghty studied 14 existing single-family stick-built and manufactured homes with zonal heating systems and found that small, split-system heat pumps saved about 4,000 to 4,500 kWh/year. With an initial heating load of 6.9 kWh/sf-year, a 32.5% savings yields an appropriate post-installation annual energy use of 4.65 kWh/sf-year (from Baylon, "Ductless Heat Pump Engineering Analysis", December, 2012).
Note: This is a deemed measure under the October 1, 2014 BPA "Energy Efficiency Implementation Manual". The deemed amount is $800 to $1200 per unit depending upon existing heating source (baseboard versus electric forced air furnace).
Energy Use of Emerging Technology:
4.6 kWh per square foot per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Potential number of units replaced by this technology:
We can only count in the technical potential of those homes currently heated by electrical appliances. It is estimated that 70.1% of manufactured homes in the Northwest are heated with electricity. We make the simplifying assumption that electrically-heated homes are the same average size as each category of home with all heating sources, so to get an estimate of square footage, we multiply the total square footage for manufactured homes times the percentage of homes that are electrically heated in that category.
Regional Technical Potential:
Type of Home
No. of Homes
% Electrically Heated
| || |
1.11 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Installed first cost per: square foot
Emerging Technology Unit Cost (Equipment Only): $5.33
Baseline Technology Unit Cost (Equipment Only): $0.56
Installed costs for single zone systems are around $3,500 for a1-ton system and up to around $8,500 for a 5-ton system. This technology is available in up to eight zones on a single condensing unit, adding about $1,200per zone. Prices depend on control systems selected, contractor familiarity with this technology, size of building, etc. The total installed cost for a 1.5 ton ductless heat pump (in mid-2014) was about $4800 including wireless programmable controls. These costs are approximately 20% higher than an equivalent constant-speed heat pump system. Given that a one-ton unit will serve a residential area of 600 sf, the 1.5 ton unit captures some economies of scale and has a total cost of $5.33/sf.
The assumed baseboard heating cost is $0.56/sf. (From Means, an 8-foot baseboard has a cost of about $193 and has a power output of 2 kW). This cost does not include wiring.
Simple payback, new construction (years): 23.3
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
The description of this technology, and the equipment available for this application is essentially the same as technology #300: Ductless Mini-Split Heat Pumps with Variable Speed Compressors, but this is specifically for application in multifamily residential applications. This covers a single outdoor unit and up to eight indoor units. For some multifamily applications, a full variable refrigerant flow system with more than eight indoor units may be more appropriate. See #300 for more technical detail.
End User Drawbacks:
Energy savings will be reduced for manufactured homes with supplemental wood-fueled heating. A "takeback" in savings will occur in homes that currently do not have air conditioning. Savings will also be lessened for homes that are currently heated with conventional heat pumps.
Operations and Maintenance Costs:
No information available.
Currently no data available.