SciTech Connect

Title: NREL Documents Efficiency of Mini-Split Heat Pumps (Fact Sheet)

NREL Documents Efficiency of Mini-Split Heat Pumps (Fact Sheet) A new report delivers mini-split heat pump (MSHP) performance data for use in whole-building simulation tools. Mini-split heat pumps (MSHPs) are highly efficient refrigerant-based air conditioning and heating systems that permit room-by-room conditioning and control in homes. Because of their size, efficiency, and price, MSHPs are very popular overseas and are gaining market share in energy-efficient home upgrades in the United States. They are a good option for retrofitting older homes that lack ductwork. To evaluate MSHP cost effectiveness and performance in U.S. homes, National Renewable Energy Laboratory (NREL) researchers are studying these systems in the laboratory, simulated buildings, and field test settings. A new NREL report describes an innovative laboratory approach to testing MSHPs and includes experimental performance maps for use in whole-building simulation tools. Most public information on MSHP performance is provided by equipment manufacturers, and is typically limited to performance at a single operating speed for heating and cooling. Mini-split heat pumps use variable speed components that spin up and down to continuously meet the heating or cooling need, significantly improving a system's operating efficiency. Measuring that efficiency in a laboratory is challenging and required new approaches to performance testing. NREL researchers worked with colleagues at Purdue more » University's Herrick Labs and Ecotope, Inc. to refine and apply this new approach to a suite of MSHP products. Researchers measured the performance of two MSHPs across a variety of operating conditions, which allowed, for the first time, development of accurate building simulation MSHP models. In the laboratory tests, researchers found that both MSHPs achieved manufacturer-reported performance at rating conditions. However, at other temperature and humidity conditions, the heat pumps capacity ranged from 40% above to 54% below the manufacturer-reported values. Knowing how performance varies is critical in order to reasonably estimate annual energy consumption of a MSHP, and to compare MSHPs to other heating and cooling options. Mini-split heat pump efficiency (COP) was seen to significantly exceed rated efficiency at low compressor speeds-a very important effect. « less
Publication Date:
OSTI Identifier:OSTI ID: 1045050
Report Number(s):NREL/FS-5500-54846
TRN: US201214%%1068
DOE Contract Number:AC36-08GO28308
Resource Type:Technical Report
Resource Relation:Related Information: NREL Highlights, Research & Development, NREL (National Renewable Energy Laboratory)
Research Org:National Renewable Energy Laboratory (NREL), Golden, CO.
Sponsoring Org:USDOE Office of Energy Efficiency and Renewable Energy
Country of Publication:United States
Language:English
Subject: 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 14 SOLAR ENERGY; AIR CONDITIONING; CAPACITY; COMPRESSORS; EFFICIENCY; ENERGY CONSUMPTION; FIELD TESTS; HEAT PUMPS; HEATING; HEATING SYSTEMS; HUMIDITY; MANUFACTURERS; MARKET; NATIONAL RENEWABLE ENERGY LABORATORY; PERFORMANCE TESTING; PUBLIC INFORMATION; RETROFITTING; SIMULATION; SPIN; TESTING MINI-SPLIT HEAT PUMPS; MSHP; WHOLE-BUILDING SIMULATION TOOLS; HOME EFFICIENCY; HVAC; Buildings; Electricity, Resources, and Buildings Systems