Ductless Mini-Split Heat Pump for Multi-Family Housing

Summary

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Ductless Mini-Split Heat Pump for Multi-Family Housing

Ductless Mini-split Heat Pumps in Multi-Family Homes: Variable-Speed Compressors vs. Constant-Speed Compressors

Mini-Split Heat Pumps with Variable Speed Compressors, but this application is designed specifically for use in multi-family homes.

Synopsis:

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, are available with 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 residences within 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.

Energy Savings: 41%

Energy Savings Rating: Comprehensive Analysis What's this?

Level	Status	Description
1	Concept not validated	Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2	Concept validated:	An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3	Limited assessment	An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4	Extensive assessment	Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5	Comprehensive analysis	Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6	Approved measure	Protocols for technology application are established and approved.

Simple Payback, New Construction (years): 49.7 What's this?

Simple Payback, Retrofit (years): 55.7 What's this?

Simple Payback is one tool used to estimate the cost-effectiveness of a proposed investment, such as the investment in an energy efficient technology. Simple payback indicates how many years it will take for the initial investment to "pay itself back." The basic formula for calculating a simple payback is:

Simple Payback = Incremental First Cost / Annual Savings

The Incremental Cost is determined by subtracting the Baseline First Cost from the Measure First Cost.

For New Construction, the Baseline First Cost is the cost to purchase the standard practice technology. The Measure First Cost is the cost of the alternative, more energy efficienct technology. Installation costs are not included, as it is assumed that installation costs are approximately the same for the Baseline and the Emerging Technology.

For Retrofit scenarios, the Baseline First Cost is $0, since the baseline scenario is to leave the existing equipment in place. The Emerging Technology First Cost is the Measure First Cost plus Installation Cost (the cost of the replacement technology, plus the labor cost to install it). Retrofit scenarios generally have a higher First Cost and longer Simple Paybacks than New Construction scenarios.

Simple Paybacks are called "simple" because they do not include details such as the time value of money or inflation, and often do not include operations and maintenance (O&M) costs or end-of-life disposal costs. However, they can still provide a powerful tool for a quick assessment of a proposed measure. These paybacks are rough estimates based upon best available data, and should be treated with caution. For major financial decisions, it is suggested that a full Lifecycle Cost Analysis be performed which includes the unique details of your situation.

The energy savings estimates are based upon an electric rate of $.09/kWh, and are calculated by comparing the range of estimated energy savings to the baseline energy use. For most technologies, this results in "Typical," "Fast" and "Slow" payback estimates, corresponding with the "Typical," "High" and "Low" estimates of energy savings, respectively.

Details

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Ductless Mini-Split Heat Pump for Multi-Family Housing

Ductless Mini-split Heat Pumps in Multi-Family Homes: Variable-Speed Compressors vs. Constant-Speed Compressors

Mini-Split Heat Pumps with Variable Speed Compressors, but this application is designed specifically for use in multi-family homes.

Item ID: 302

Sector: Residential

Energy System: HVAC--Heat Pumps

Synopsis:

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.

Baseline Example:

Baseline Description: Multi-Family with Electric Space Heat
Baseline Energy Use: 2.6 kWh per year per square foot

Comments:

We can only count in the technical potential those multi-family homes currently heated with electrical energy. According to estimates in the Northwest Energy Efficiency Alliance's (NEEA's) 2013 "Residential Building Stock Assessment (RBSA):Multifamily Characteristics and Energy Use", 81.7% of multi-family homes in the Northwest are heated with baseboard electrical heaters (David Baylon, 9/5/2013). Each multi-family home averages 766 sf with an annual heating energy use of 2,000 kWh/year. This indicates an EUI of 2.6 kWh/sf-year.

Manufacturer's Energy Savings Claims: Currently no data available.

Best Estimate of Energy Savings:

"Typical" Savings: 41%
Energy Savings Reliability: 5 - Comprehensive Analysis

Comments:

Energy savings will depend on weather conditions for a given site. As the bulk of the energy used is for heating, a ductless heat pump COP of 3.5 is assumed (Daiken values range from 3.2 to 3.8). This simplistic assumption results in a projected heating energy savings of about 71% relative to electrical baseboard heaters.

Ecotope conducted a study of energy savings due to deploying ductless heat pumps in multi-family buildings in 2012. Participants included two apartment complexes with a total of 188 units. Calculated heating savings due to billing analysis revealed a savings of 736 kWh/year in Richland, WA, versus 912 kWh/year in Eugene, OR. Cooling figures were a savings of 386 kWh/year in Richland, with an increase of 143 kWh/year in Eugene (from Ben Larson, Ecotope, "Ductless Heat Pump Retrofits in Multifamily and Small Commercial Buildings") (Larson, 2012). The analysts decided to drop cooling savings from the analysis as increases in use in mild climates will tend to offset or balance out savings in climates with high cooling loads.

Savings were less than expected due to "takeback" or significant increases in delivered heat in the metered units. The increase in post-installation output heat delivered ranged from 39% at Eugene to 78% in Richland. The final result was an overall savings number of 824 kWh/year per unit. As mentioned previously, each multi-family home averages 766 sf with an annual heating energy use of 2,000 kWh/year. A savings of 824 kWh/year is equivalent to an energy use reduction of 41.2%. This result will be used in our analysis.

Energy Use of Emerging Technology:

1.5 kWh per square foot per year What's this?

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.))

Technical Potential:
Units: square foot
Potential number of units replaced by this technology: 540,149,471
Comments:

We can only count in the technical potential those multi-family homes currently heated with electrical energy. According to estimates in the Northwest Energy Efficiency Alliance's (NEEA's) 2013 "Residential Building Stock Assessment (RBSA):Multifamily Characteristics and Energy Use", 81.7% of multi-family homes in the Northwest are heated with baseboard electrical heaters (David Baylon, 9/5/2013). We make the simplifying assumption that electrically-heated multi-family units are the same average size as each category of units with all heating sources, so to get an estimate of square footage, we multiply the total square footage of each type of multi-family unit times the percentage of units that are electrically heated in that category.

Type of Home No. of Homes Avg. Size Total s.f. % Electrically Heated s.f. Electrical
Multi-Family 863,104 766 661,137,664 81.7 540,149,471

Regional Technical Potential:
0.58 TWh per year
66 aMW
What's this?

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)

First Cost:

Installed first cost per: square foot
Emerging Technology Unit Cost (Equipment Only): $5.33
Emerging Technology Installation Cost (Labor, Disposal, Etc.): $0.01
Baseline Technology Unit Cost (Equipment Only): $0.56

Comments:

Installed costs for single zone systems are around $3,500 for a 1-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 $1,200 per 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 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. With a 20% price premium over conventional heating equipment, the assumed conventional equipment cost is $4.44/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).

Cost Effectiveness:

Simple payback, new construction (years): 49.7

Simple payback, retrofit (years): 55.7

What's this?

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.

Detailed Description:

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. See #300 for more technical detail.

Operations and Maintenance Costs:

No information available.

Effective Life: Currently no data available.

Reference and Citations:

David Baylon, et. al., 09/18/2012. 2011 Residential Building Stock Assessment: Single-Family Characteristics and Energy Use
Northwest Energy Efficiency Alliance & Ecotope

David Baylon, 09/05/2013. Residential Building Stock Assessment: Multifamily Characteristics and Energy Use
Northwest Energy Efficiency Alliance

Ben Larson, 12/07/2012. Ductless Heat Pump Retrofits in Multifamily and Small Commercial Buildings
BPA Energy Efficiency Emergency Technologies Program

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Ductless Mini-Split Heat Pump for Multi-Family Housing

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