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Title: Field Investigation of an Air-Source Cold Climate Heat Pump

Abstract

In the U.S., there are approximately 2.6 million dwellings that use electricity for heating in cold and very cold regions with an annual energy consumption of 0.16 quads (0.17 EJ). A high performance cold climate heat pump (CCHP) would result in significant savings over current technologies (greater than 60% compared to electric resistance heating). We developed an air-source cold climate heat pump, which uses tandem compressors, with a single compressor rated for the building design cooling load, and running two compressors to provide, at -13 F (-25 C), 75% of rated heating capacity. The tandem compressors were optimized for heating operation and are able to tolerate discharge temperatures up to 280 F (138 C). A field investigation was conducted in the winter of 2015, in an occupied home in Ohio, USA. During the heating season, the seasonal COP was measured at 3.16, and the heat pump was able to operate down to -13 F (-25 C) and eliminate resistance heat use. The heat pump maintained an acceptable comfort level throughout the heating season. In comparison to a previous single-speed heat pump in the home, the CCHP demonstrated more than 40% energy savings in the peak heating load month. This papermore » illustrates the measured field performance, including compressor run time, frost/defrosting operations, distributions of building heating load and capacity delivery, comfort level, field measured COPs, etc.« less

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Technologies Research and Integration Center (BTRIC)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1356936
DOE Contract Number:
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 12th IEA heat pump conference 2017, Rotterdam, Netherlands, 20170515, 20170519
Country of Publication:
United States
Language:
English
Subject:
Cold Climate Heat Pump

Citation Formats

Shen, Bo, Abdelaziz, Omar, Rice, C Keith, and Baxter, Van D. Field Investigation of an Air-Source Cold Climate Heat Pump. United States: N. p., 2017. Web.
Shen, Bo, Abdelaziz, Omar, Rice, C Keith, & Baxter, Van D. Field Investigation of an Air-Source Cold Climate Heat Pump. United States.
Shen, Bo, Abdelaziz, Omar, Rice, C Keith, and Baxter, Van D. Sun . "Field Investigation of an Air-Source Cold Climate Heat Pump". United States. doi:.
@article{osti_1356936,
title = {Field Investigation of an Air-Source Cold Climate Heat Pump},
author = {Shen, Bo and Abdelaziz, Omar and Rice, C Keith and Baxter, Van D},
abstractNote = {In the U.S., there are approximately 2.6 million dwellings that use electricity for heating in cold and very cold regions with an annual energy consumption of 0.16 quads (0.17 EJ). A high performance cold climate heat pump (CCHP) would result in significant savings over current technologies (greater than 60% compared to electric resistance heating). We developed an air-source cold climate heat pump, which uses tandem compressors, with a single compressor rated for the building design cooling load, and running two compressors to provide, at -13 F (-25 C), 75% of rated heating capacity. The tandem compressors were optimized for heating operation and are able to tolerate discharge temperatures up to 280 F (138 C). A field investigation was conducted in the winter of 2015, in an occupied home in Ohio, USA. During the heating season, the seasonal COP was measured at 3.16, and the heat pump was able to operate down to -13 F (-25 C) and eliminate resistance heat use. The heat pump maintained an acceptable comfort level throughout the heating season. In comparison to a previous single-speed heat pump in the home, the CCHP demonstrated more than 40% energy savings in the peak heating load month. This paper illustrates the measured field performance, including compressor run time, frost/defrosting operations, distributions of building heating load and capacity delivery, comfort level, field measured COPs, etc.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2017},
month = {Sun Jan 01 00:00:00 EST 2017}
}

Conference:
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  • A multiple-source heat pump for heating in cold climates has been investigated. The heat pump had four modes of operation: two solar-source modes, and ambient-air-source mode, and a storage-source mode. Solar collectors cooled by Refrigerant 12 served as the evaporator for the heat pump. The solar energy collected was used to heat space air or water storage if heating was not required. During periods of low solar radiation and at night, ambient air was circulated through the collectors, which served as the evaporator to extract heat from the ambient air. A tempering heat exchanger was used in series with themore » storage evaporator to enable the heat pump to extract heat under stable operating conditions when the storage water was heated to a high temperature. The solar-source mode operated with minimum collector efficiencies of 0.5 at ambient temperatures as low as -10/sup 0/F (-23/sup 0/C). The air-source mode operated with a minimum output of 85 Btuh/ft/sup 2/ (268 Watts/m/sup 2/) of net frontal collector area at an ambient temperature of 0/sup 0/F (-18/sup 0/C). The water storage was heated to 125/sup 0/F (52/sup 0/C) and cooled to 42/sup 0/F (5/sup 0/C). It was noted that at low refrigerant flow rates even when the time-averaged temperature of the refrigerant at the location controlled by the expansion valve was higher than the saturation temperature, the refrigerant at this location was actually wet. This possible condition should be taken into account in calculating from experimental data the energy absorbed by collectors.« less
  • This paper describes the field performance of space conditioning and water heating equipment in four single-family residential structures with advanced thermal envelopes. Each structure features a different, advanced thermal envelope design: structural insulated panel (SIP); optimum value framing (OVF); insulation with embedded phase change materials (PCM) for thermal storage; and exterior insulation finish system (EIFS). Three of the homes feature ground-source heat pumps (GSHPs) for space conditioning and water heating while the fourth has a two-capacity air-source heat pump (ASHP) and a heat pump water heater (HPWH). Two of the GCHP-equipped homes feature horizontal ground heat exchange (GHX) loops thatmore » utillize the existing foundation and utility service trenches while the third features a vertical borehole with vertical u-tube GHX. All of the houses were operated under the same simulated occupancy conditions. Operational data on the house HVAC/Water heating (WH) systems are presented and factors influencing overall performance are summarized.« less
  • An air-to-air heat pump was installed in an unoccupied single-family residence and operated in a two-year test to characterize dynamic losses in capacity and efficiency due to cycling, frosting, and defrosting. During the heating season, defrosting losses were responsible for 10.2% of the total energy consumption (excluding supplemental electric resistance heating), frosting losses for 3.7%, start-up transient losses for 8.5%, and off-cycle parasitics for 3.3%. The heating cyclic degradation factor, C/sub d/, was estimated to be 0.26. Cooling mode steady-state performance of the heat pump was degraded from the manufacturer's ratings due most likely to a small refrigerant leak resultingmore » in a slight charge deficiency. However, using the site measured performance as the steady-state base, it was found that start-up transient losses accounted for 2.8% of the total energy use and off-cycle parasitics for 4.4%. The cooling C/sub d/ was estimated to be 0.11 on this basis.« less
  • The objective of the air-source heat pump field tests at ORNL has been to develop a data base of field-measured heat pump performance. Information obtained includes seasonal performance factors; magnitudes of frosting, defrosting, and cycling losses; and an assessment of the effect of a desuperheater water heater on system performance.