OSTI.GOV Technical Report: Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3
Title: Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3
The International Energy Agency (IEA) Heat Pumping Technologies (HPT) Annex 49, "Design and Integration of Heat Pumps for Nearly Zero Energy Buildings," deals with the application of heat pumps (HPs) as a core component of the HVAC system for nearly or net-zero energy buildings. This report covers the Task 3 activities of the US team.Three institutions are involved on the US team and have worked on the following projects.•Oak Ridge National Laboratory (ORNL) summarized development activities since the conclusion of IEA HPT Annex 40 for several integrated HP (IHP) systems—electric ground-source IHP and air-source IHP versions and engine-driven AS-IHP version.•The University of Maryland partnered with ORNL and Blue Bear Management to develop a personal cooling device called RoCo that can provide personalized conditioned air to occupants in inadequately or unconditioned environments. With RoCo, building facility management can elevate the HVAC thermostat settings without compromising occupants' thermal comfort. Researchers have found that a 4°F increase in thermostat settings can save 12–30% energy savings. Therefore, RoCo is a promising technology that can help reduce building energy consumption and facilitate achievement of net-zero energy building performance. •The National Institute of Standards and Technology (NIST) is working on a field study effort on themore » NIST Net-Zero Energy Residential Test Facility. Two air-source split-system HPs were installed in a residential, net-zero energy home that was constructed as a laboratory on the NIST campus in Gaithersburg, Maryland. The first HP was a two-stage, 7 kW (2 ton), 15.8 seasonal energy efficiency ratio (SEER), 9.05 heating seasonal performance factor (HSPF) conventionally ducted system; the second HP was a variable-speed, 10.6 kW (3 ton), 14 SEER, 8.35 HSPF, high-velocity ducted system. These two systems operated side by side, using separate supply ducts and a common return duct, on a weekly alternating schedule to condition the home that was operated with very consistent simulated thermal loads. The team wanted to determine whether the high-velocity system could provide comparable energy-use efficiency to the conventional system. The results of this study showed that it did meet the required loads and had slightly greater efficiency; the average cooling coefficient of performance (COP) was (0.40 ± 0.11) higher, and the average heating COP was statistically equal. A new firmware was provided at the end of the heating season that greatly improved the performance of the high-velocity system; its average heating COP went from (1.8 ± 0.9) to (2.5 ± 1.1) at a 95% confidence level. The new firmware heating COP averaged (1.05 ± 0.23) higher than the old firmware over the same outdoor temperatures. The defrost performance is very different for these two systems, yet they consumed equivalent energy per HDD. The conventional system uses a timed-initiate, temperature-terminate algorithm with auxiliary electric resistive heating, whereas the high-velocity system uses calculated evaporator parameters with a hot-gas bypass before a full reverse-cycle defrost with no supplementary resistive heat.« less
Baxter, Van D. [1];
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Abuheiba, Ahmad [1];
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Radermacher, Reinhard [2]; Payne, W. Vance [3]; Dougherty, Brian [4]; Ling, Jiazhen [2]; Srebric, Jelena [2]
National Institute of Standards and Technology (NIST), Gaithersburg, MD
National Institute of Standards and Technology, Gaithersburg, MD
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
ORNL/TM-2020/1604
IEA/HPT Annex 49
DOE Contract Number:
AC05-00OR22725
Baxter, Van D., Abuheiba, Ahmad, Radermacher, Reinhard, Payne, W. Vance, Dougherty, Brian, Ling, Jiazhen, and Srebric, Jelena. Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3. United States: N. p., 2020. Web. doi:10.2172/1665989.
Baxter, Van D., Abuheiba, Ahmad, Radermacher, Reinhard, Payne, W. Vance, Dougherty, Brian, Ling, Jiazhen, & Srebric, Jelena. Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3. United States. https://doi.org/10.2172/1665989
Baxter, Van D., Abuheiba, Ahmad, Radermacher, Reinhard, Payne, W. Vance, Dougherty, Brian, Ling, Jiazhen, and Srebric, Jelena. Wed . "Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3". United States. https://doi.org/10.2172/1665989. https://www.osti.gov/servlets/purl/1665989.
title = {Technology Development and Field Monitoring in nZEB - US Country report IEA HPT Annex 49 Task 3},
author = {Baxter, Van D. and Abuheiba, Ahmad and Radermacher, Reinhard and Payne, W. Vance and Dougherty, Brian and Ling, Jiazhen and Srebric, Jelena},
abstractNote = {The International Energy Agency (IEA) Heat Pumping Technologies (HPT) Annex 49, "Design and Integration of Heat Pumps for Nearly Zero Energy Buildings," deals with the application of heat pumps (HPs) as a core component of the HVAC system for nearly or net-zero energy buildings. This report covers the Task 3 activities of the US team.Three institutions are involved on the US team and have worked on the following projects.•Oak Ridge National Laboratory (ORNL) summarized development activities since the conclusion of IEA HPT Annex 40 for several integrated HP (IHP) systems—electric ground-source IHP and air-source IHP versions and engine-driven AS-IHP version.•The University of Maryland partnered with ORNL and Blue Bear Management to develop a personal cooling device called RoCo that can provide personalized conditioned air to occupants in inadequately or unconditioned environments. With RoCo, building facility management can elevate the HVAC thermostat settings without compromising occupants' thermal comfort. Researchers have found that a 4°F increase in thermostat settings can save 12–30% energy savings. Therefore, RoCo is a promising technology that can help reduce building energy consumption and facilitate achievement of net-zero energy building performance. •The National Institute of Standards and Technology (NIST) is working on a field study effort on the NIST Net-Zero Energy Residential Test Facility. Two air-source split-system HPs were installed in a residential, net-zero energy home that was constructed as a laboratory on the NIST campus in Gaithersburg, Maryland. The first HP was a two-stage, 7 kW (2 ton), 15.8 seasonal energy efficiency ratio (SEER), 9.05 heating seasonal performance factor (HSPF) conventionally ducted system; the second HP was a variable-speed, 10.6 kW (3 ton), 14 SEER, 8.35 HSPF, high-velocity ducted system. These two systems operated side by side, using separate supply ducts and a common return duct, on a weekly alternating schedule to condition the home that was operated with very consistent simulated thermal loads. The team wanted to determine whether the high-velocity system could provide comparable energy-use efficiency to the conventional system. The results of this study showed that it did meet the required loads and had slightly greater efficiency; the average cooling coefficient of performance (COP) was (0.40 ± 0.11) higher, and the average heating COP was statistically equal. A new firmware was provided at the end of the heating season that greatly improved the performance of the high-velocity system; its average heating COP went from (1.8 ± 0.9) to (2.5 ± 1.1) at a 95% confidence level. The new firmware heating COP averaged (1.05 ± 0.23) higher than the old firmware over the same outdoor temperatures. The defrost performance is very different for these two systems, yet they consumed equivalent energy per HDD. The conventional system uses a timed-initiate, temperature-terminate algorithm with auxiliary electric resistive heating, whereas the high-velocity system uses calculated evaporator parameters with a hot-gas bypass before a full reverse-cycle defrost with no supplementary resistive heat.},
doi = {10.2172/1665989},
url = {https://www.osti.gov/biblio/1665989}, journal = {},
number = ,
volume = ,
Technical Report:
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https://doi.org/10.2172/1665989
Heat pump concepts for nZEB Technology developments, design tools and testing of heat pump systems for nZEB in the USA: Country report IEA HPT Annex 40 Task 2, Task 3 and Task 4 of the USA
Technical Report Baxter, Van D. ; Payne, W. Vance ; Ling, Jiazhen ; ...
The IEA HPT Annex 40 "Heat pump concepts for Nearly Zero Energy Buildings" deals with the application of heat pumps as a core component of the HVAC system for Nearly or Net Zero energy buildings (nZEB). This report covers Task 2 on the system comparison and optimisation and Task 3 dedicated to the development of adapted technologies for nZEB and field monitoring results of heat pump systems in nZEB. In the US team three institutions are involved and have worked on the following projects: The Oak Ridge National Laboratory (ORNL) will summarize development activities through the field demonstration stage formore » several integrated heat pump (IHP) systems electric ground-source (GS-IHP) and air-source (AS-IHP) versions and an engine driven AS-IHP version. The first commercial GS-IHP product was just introduced to the market in December 2012. This work is a contribution to Task 3 of the Annex. The University of Maryland will contribute a software development project to Task 2 of the Annex. The software ThermCom evaluates occupied space thermal comfort conditions accounting for all radiative and convective heat transfer effects as well as local air properties. The National Institute of Standards and Technology (NIST) is working on a field study effort on the NIST Net Zero Energy Residential Test Facility (NZERTF). This residential building was constructed on the NIST campus and officially opened in summer 2013. During the first year, between July 2013 and June 2014, baseline performance of the NZERTF was monitored under a simulated occupancy protocol. The house was equipped with an air-to-air heat pump which included a dedicated dehumidification operating mode. Outdoor conditions, internal loads and modes of heat pump operation were monitored. Field study results with respect to heat pump operation will be reported and recommendations on heat pump optimization for a net zero energy building will be provided. This work is a contribution to Task 3 of the Annex.« less
Dynamic control of heat pumps: Final report
Technical Report Glamm, P
Air-to-air heat pumps suffer from on/off and frost accumulation/defrost cyclic losses which reduce their seasonal efficiencies from that expected by examination of steady state efficiencies only. A significant fraction of the losses are due to non-ideal operating characteristics of the refrigerant expansion device. In addition, the ''off design'' expansion device characteristics may detract from steady state operating efficiency, particularly at extreme operating conditions. A heat pump testing program has been completed which identified ideal expansion valve characteristics and control strategies for minimizing cyclic losses and maximizing steady state efficiency. Several control concepts were tested and the most promising recommended formore » further development. New expansion value designs were tested and evaluated in comparison to the ideal characteristics. One expansion valve design has been found which can display the desired characteristics providing it is controlled properly. The use of the new control concepts on a split system heat pump increases SEER by 5.2% and HSPF by 0.0% to 3.6% depending on climate, relative to a well designed heat pump with zero bleed thermostatic expansion valves indoors and bleed type thermostatic expansion valves outdoors.« less
Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes - Update to Include Evaluation of Impact of Including a Humidifier Option
Technical Report Baxter, Van D
The long range strategic goal of the Department of Energy's Building Technologies (DOE/BT) Program is to create, by 2020, technologies and design approaches that enable the construction of net-zero energy homes at low incremental cost (DOE/BT 2005). A net zero energy home (NZEH) is a residential building with greatly reduced needs for energy through efficiency gains, with the balance of energy needs supplied by renewable technologies. While initially focused on new construction, these technologies and design approaches are intended to have application to buildings constructed before 2020 as well resulting in substantial reduction in energy use for all building typesmore » and ages. DOE/BT's Emerging Technologies (ET) team is working to support this strategic goal by identifying and developing advanced heating, ventilating, air-conditioning, and water heating (HVAC/WH) technology options applicable to NZEHs. In FY05 ORNL conducted an initial Stage 1 (Applied Research) scoping assessment of HVAC/WH systems options for future NZEHs to help DOE/BT identify and prioritize alternative approaches for further development. Eleven system concepts with central air distribution ducting and nine multi-zone systems were selected and their annual and peak demand performance estimated for five locations: Atlanta (mixed-humid), Houston (hot-humid), Phoenix (hot-dry), San Francisco (marine), and Chicago (cold). Performance was estimated by simulating the systems using the TRNSYS simulation engine (Solar Energy Laboratory et al. 2006) in two 1800-ft{sup 2} houses--a Building America (BA) benchmark house and a prototype NZEH taken from BEopt results at the take-off (or crossover) point (i.e., a house incorporating those design features such that further progress towards ZEH is through the addition of photovoltaic power sources, as determined by current BEopt analyses conducted by NREL). Results were summarized in a project report, HVAC Equipment Design options for Near-Zero-Energy Homes--A Stage 2 Scoping Assessment, ORNL/TM-2005/194 (Baxter 2005). The 2005 study report describes the HVAC options considered, the ranking criteria used, and the system rankings by priority. In 2006, the two top-ranked options from the 2005 study, air-source and ground-source versions of a centrally ducted integrated heat pump (IHP) system, were subjected to an initial business case study. The IHPs were subjected to a more rigorous hourly-based assessment of their performance potential compared to a baseline suite of equipment of legally minimum efficiency that provided the same heating, cooling, water heating, demand dehumidification, and ventilation services as the IHPs. Results were summarized in a project report, Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes, ORNL/TM-2006/130 (Baxter 2006a). The present report is an update to that document which summarizes results of an analysis of the impact of adding a humidifier to the HVAC system to maintain minimum levels of space relative humidity (RH) in winter. The space RH in winter has direct impact on occupant comfort and on control of dust mites, many types of disease bacteria, and 'dry air' electric shocks. Chapter 8 in ASHRAE's 2005 Handbook of Fundamentals (HOF) suggests a 30% lower limit on RH for indoor temperatures in the range of {approx}68-69F based on comfort (ASHRAE 2005). Table 3 in chapter 9 of the same reference suggests a 30-55% RH range for winter as established by a Canadian study of exposure limits for residential indoor environments (EHD 1987). Harriman, et al (2001) note that for RH levels of 35% or higher, electrostatic shocks are minimized and that dust mites cannot live at RH levels below 40%. They also indicate that many disease bacteria life spans are minimized when space RH is held within a 30-60% range. From the foregoing it is reasonable to assume that a winter space RH range of 30-40% would be an acceptable compromise between comfort considerations and limitation of growth rates for dust mites and many bacteria. In addition it reports some corrections made to the simulation models used in order to correct some errors in the TRNSYS building model for Atlanta and in the refrigerant pressure drop calculation in the water-to-refrigerant evaporator module of the ORNL Heat Pump Design Model (HPDM) used for the IHP analyses. These changes resulted in some minor differences between IHP performance as reported in Baxter (2006) and in this report.« less
Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes - Business Case Assessment
The long range strategic goal of the Department of Energy's Building Technologies (DOE/BT) Program is to create, by 2020, technologies and design approaches that enable the construction of net-zero energy homes at low incremental cost (DOE/BT 2005). A net zero energy home (NZEH) is a residential building with greatly reduced needs for energy through efficiency gains, with the balance of energy needs supplied by renewable technologies. While initially focused on new construction, these technologies and design approaches are intended to have application to buildings constructed before 2020 as well resulting in substantial reduction in energy use for all building typesmore » and ages. DOE/BT's Emerging Technologies (ET) team is working to support this strategic goal by identifying and developing advanced heating, ventilating, air-conditioning, and water heating (HVAC/WH) technology options applicable to NZEHs. Although the energy efficiency of heating, ventilating, and air-conditioning (HVAC) equipment has increased substantially in recent years, new approaches are needed to continue this trend. Dramatic efficiency improvements are necessary to enable progress toward the NZEH goals, and will require a radical rethinking of opportunities to improve system performance. The large reductions in HVAC energy consumption necessary to support the NZEH goals require a systems-oriented analysis approach that characterizes each element of energy consumption, identifies alternatives, and determines the most cost-effective combination of options. In particular, HVAC equipment must be developed that addresses the range of special needs of NZEH applications in the areas of reduced HVAC and water heating energy use, humidity control, ventilation, uniform comfort, and ease of zoning. In FY05 ORNL conducted an initial Stage 1 (Applied Research) scoping assessment of HVAC/WH systems options for future NZEHs to help DOE/BT identify and prioritize alternative approaches for further development. Eleven system concepts with central air distribution ducting and nine multi-zone systems were selected and their annual and peak demand performance estimated for five locations: Atlanta (mixed-humid), Houston (hot-humid), Phoenix (hot-dry), San Francisco (marine), and Chicago (cold). Performance was estimated by simulating the systems using the TRNSYS simulation engine (Solar Energy Laboratory et al. 2006) in two 1800-ft{sup 2} houses--a Building America (BA) benchmark house and a prototype NZEH taken from BEopt results at the take-off (or crossover) point (i.e., a house incorporating those design features such that further progress towards ZEH is through the addition of photovoltaic power sources, as determined by current BEopt analyses conducted by NREL). Results were summarized in a project report, 'HVAC Equipment Design options for Near-Zero-Energy Homes--A Stage 2 Scoping Assessment', ORNL/TM-2005/194 (Baxter 2005). The 2005 study report describes the HVAC options considered, the ranking criteria used, and the system rankings by priority. Table 1 summarizes the energy savings potential of the highest scoring options from the 2005 study for all five locations. All system options were scored by the ORNL building equipment research team and by William Goetzler of Navigant Consulting. These scores were reviewed by DOE/BT's Residential Integration program leaders and Building America team members. Based on these results, the two centrally ducted integrated heat pump (IHP) systems (air source and ground source versions) were selected for advancement to Stage 2 (Exploratory Development) business case assessments in FY06. This report describes results of these business case assessments. It is a compilation of three separate reports describing the initial business case study (Baxter 2006a), an update to evaluate the impact of an economizer cooling option (Baxter 2006b), and a second update to evaluate the impact of a winter humidification option (Baxter 2007). In addition it reports some corrections made subsequent to release of the first two reports to correct some errors in the TRNSYS building model for Atlanta and in the refrigerant pressure drop calculation in the water-to-refrigerant evaporator module of the ORNL Heat Pump Design Model (HPDM) used for the IHP analyses. These changes resulted in some minor differences between IHP performance as reported in Baxter (2006a, b) and in this report.« less
Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes -- Update to Include Analyses of an Economizer Option and Alternative Winter Water Heating Control Option
The long range strategic goal of the Department of Energy's Building Technologies (DOE/BT) Program is to create, by 2020, technologies and design approaches that enable the construction of net-zero energy homes at low incremental cost (DOE/BT 2005). A net zero energy home (NZEH) is a residential building with greatly reduced needs for energy through efficiency gains, with the balance of energy needs supplied by renewable technologies. While initially focused on new construction, these technologies and design approaches are intended to have application to buildings constructed before 2020 as well resulting in substantial reduction in energy use for all building typesmore » and ages. DOE/BT's Emerging Technologies (ET) team is working to support this strategic goal by identifying and developing advanced heating, ventilating, air-conditioning, and water heating (HVAC/WH) technology options applicable to NZEHs. Although the energy efficiency of heating, ventilating, and air-conditioning (HVAC) equipment has increased substantially in recent years, new approaches are needed to continue this trend. Dramatic efficiency improvements are necessary to enable progress toward the NZEH goals, and will require a radical rethinking of opportunities to improve system performance. The large reductions in HVAC energy consumption necessary to support the NZEH goals require a systems-oriented analysis approach that characterizes each element of energy consumption, identifies alternatives, and determines the most cost-effective combination of options. In particular, HVAC equipment must be developed that addresses the range of special needs of NZEH applications in the areas of reduced HVAC and water heating energy use, humidity control, ventilation, uniform comfort, and ease of zoning. In FY05 ORNL conducted an initial Stage 1 (Applied Research) scoping assessment of HVAC/WH systems options for future NZEHs to help DOE/BT identify and prioritize alternative approaches for further development. Eleven system concepts with central air distribution ducting and nine multi-zone systems were selected and their annual and peak demand performance estimated for five locations: Atlanta (mixed-humid), Houston (hot-humid), Phoenix (hot-dry), San Francisco (marine), and Chicago (cold). Performance was estimated by simulating the systems using the TRNSYS simulation engine (Solar Energy Laboratory et al. 2006) in two 1800-ft{sup 2} houses--a Building America (BA) benchmark house and a prototype NZEH taken from BEopt results at the take-off (or crossover) point (i.e., a house incorporating those design features such that further progress towards ZEH is through the addition of photovoltaic power sources, as determined by current BEopt analyses conducted by NREL). Results were summarized in a project report, HVAC Equipment Design options for Near-Zero-Energy Homes--A Stage 2 Scoping Assessment, ORNL/TM-2005/194 (Baxter 2005). The 2005 study report describes the HVAC options considered, the ranking criteria used, and the system rankings by priority. In 2006, the two top-ranked options from the 2005 study, air-source and ground-source versions of an integrated heat pump (IHP) system, were subjected to an initial business case study. The IHPs were subjected to a more rigorous hourly-based assessment of their performance potential compared to a baseline suite of equipment of legally minimum efficiency that provided the same heating, cooling, water heating, demand dehumidification, and ventilation services as the IHPs. Results were summarized in a project report, Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes, ORNL/TM-2006/130 (Baxter 2006). The present report is an update to that document. Its primary purpose is to summarize results of an analysis of the potential of adding an outdoor air economizer operating mode to the IHPs to take advantage of free cooling (using outdoor air to cool the house) whenever possible. In addition it provides some additional detail for an alternative winter water heating/space heating (WH/SH) control strategy briefly described in the original report and corrects some minor errors.« less