Emerging Technologies CO 2 Refrigerant Heat Pumps Today Janice Peterson, P.E. ACS Contractor for Bonneville Power Administration Ken Eklund WSU Energy Program Emerging Technologies Showcase August 16, 2017
GoToWebinar Logistics • Minimize or maximize control panel • Phone lines are muted • Please use question pane to ask questions at any time, or if you have any technical issues NOTE: Today’s presentation is being recorded and will be available at http://e3tnw.org/Webinars Emerging Technologies 2
Emerging Technologies CO 2 Refrigerant Heat Pumps Today Janice Peterson, P.E. ACS Contractor for Bonneville Power Administration Ken Eklund WSU Energy Program Emerging Technologies Showcase August 16, 2017
Need for Research • The 6 th power plan called for a 50% penetration of heat pump water heaters (HPWH) by 2030 • Replacement of electric resistance water heaters in over 1 million homes • 2013 market penetration around 1% • The integrated HPWH with synthetic refrigerants have some limitations: • Rated COP of 2.5 • Single speed • High refrigerant Global Warming Potential • Need electric resistance back up • Remove heat from conditioned space • May not fit into existing space • Noise Emerging Technologies 4
Game Changing Technology Split System CO 2 Refrigerant Variable Speed Inverter Driven No Electric Element 1.5 kW Input/ 4.5 kW out From 50 to 150 F in Single Pass Emerging Technologies 5
Bonneville Funded Research 2012 2013 2014 2015 2016 2017 2018 Lab and Field Tests of Domestic Hot Water (DHW) Performance Demand Response Potential U.L. QPL * Space + DHW in New Homes Retrofit Combined Space + DHW New Applications (Pool heater, multi-family, water source) * Northwest Energy Efficiency Alliance (NEEA)/BPA Qualified Product List Emerging Technologies 6
Hurdles to Commercial Success • Familiarity • First Cost • Finding a contractor • HVAC + Plumbing + Electrical Emerging Technologies 7
Addressing the Barriers Finding a Familiarity First Cost Contractor Training/ Publish Distributor Installation Research Buy Down Guidance News stories Utility Qualified and other Incentives Product List publicity More Cost Effective Applications Emerging Technologies 8
What We Will Cover • Research on water heating only because it is necessary to understand combined systems • Research on combined space and water heating systems • Lessons learned on the best practice and use of this technology Emerging Technologies 9
Cutting Edge--Not for the Faint Hearted Requires: – Ways to import and install non UL listed equipment – Dealing with catastrophic failure – Designing new applications for expanded capabilities which leads to: • Engineering new systems • Designing monitoring for these systems • Developing new concepts for data analysis • Learning lessons never imagined at the design phase Emerging Technologies 10
Lab Test Results Outside Energy Factor COP Air Temperature (F) (EF) 17 1.74 2.1 35 2.21 2.75 50 3.11 3.7 67 3.35 4.2 95 4.3 5.0 • Linear fit of Energy Factor to Performance vs. Outside Temperature temperature 5 • Use Typical Meteorological 4 Year 3 data to calculate an Energy Factor annual Energy Factor: 3 Climate Annual EF 2 Boise 2.9 Kalispell 2.6 1 Portland 3.0 0 Seattle 2.9 0 20 40 60 80 100 Spokane 2.8 Outside Temperature (F) Emerging Technologies 11
Field Monitoring Emerging Technologies 12
HPWH Performance kWh per 100 gallons water delivered 25 20 kWh/100 gallons CO2 Split Systems 15 10 5 0 Emerging Technologies 13
Demand Reduction Operation Blue lines are hot water draws Red blocks are off-peak times when heat pump is allowed to operate Emerging Technologies 14
Impact on Load Water Heater Load Shape Total Load Shape System Off Time in Box — Could Help Flatten the Peaks! Emerging Technologies 15
Impact of Demand Reduction on System Efficiency Reduction Emerging Technologies 16
BPA Funded Research on Combined Systems TIP 326 IN HIGH EFFICIENCY HOMES TIP 338 IN EXISTING HOMES Emerging Technologies 17
Split System Combi Success! • 10 systems in climates ranging from Northern California to the Coastal Pacific Northwest provided space and water heat through one to three winters • Much was learned regarding – Equipment design – System design, setup and optimization – Monitoring Emerging Technologies 18
Successful Background • Extremely efficient as a dedicated water heater. Average 7 kWh per 100 gallons=less than 1/3 the energy used by an electric resistance water heater • System serves large loads while operating 25% of time in very cold weather • Decided to try adding another load Emerging Technologies 19
Project Design • Targeted homes with design heating loads of 10 to 15 thousand Btu per hour — current WA code house design load is 20 to 30 thousand Btu per hour. • NEEA provided recruitment, technical assistance to builders, engineering and monitoring through its Next Step Home program • BPA provided program management, building code support, installation support, lab testing and data analysis and reporting • 10 original field sites with 7 located in Heating Climate Zone 1 (≤6,000 Heating Degree Days (HDD)— Coastal), 1 in Zone 2 (6,001 to 7499 HDD —Inland) and 2 in Zone 3 (≥7,500 HDD— Mountain) Emerging Technologies 20
Combi System Emerging Technologies 21
Monitoring and Analysis • Monitoring and analyzing the performance of two loads from the same source is challenging • In the field study there are more than double the number of sensors in the dedicated water heating research • A follow-on lab study was designed to capture the interaction of the two loads Emerging Technologies 22
Field Energy Factor Field Energy Factor is a concept created by WSU Energy to represent the total system performance It accounts for heat pump energy plus all system inefficiencies including: – Tank loss – Pipe loss – Pump energy – Controls – Defrost – Freeze Protection (including heat tape) The formula is FEF = (Q DHW + Q SpaceHeat ) / Q Energy In Emerging Technologies 23
Performance Bellingham, WA McCall, ID Olympia, WA Milwaukee, OR Seattle (Ballard), WA Tacoma, WA Emerging Technologies 24
Performance Factors 4 10 3.5 7 5 3 F 1 2.5 0 20 40 60 80 100 120 E 2 Heat Heat Return Temperature 1.5 F Non Heat 180 1 160 0.5 140 0 G 120 1 5 7 10 Heat 100 Site P 80 Non Heat 60 D 40 20 0 1 5 7 10 • Lowest performance correlates with highest return water temperature (5) • Performance of Site 5 doubled in Non Heating due to colder supply water • Where DHW use drops, performance during Non Heating drops (1 & 7) • Largest daily water use correlates with highest FEF due to cold water (10) Emerging Technologies 25
Design Issues — Opportunities for Improvement • Defrost issues in cold weather when operating as a space heater were addressed in new UL listed model • Systems worked best where design load was within heat pump limits — even if load was met by total capacity • A system froze during a 10 hour power outage at 20 °F • Tank destratification occurred — especially in cold climates and with high temperature heating systems — which reduced efficiency • Cross flow may have contributed to reduced operating efficiency at some sites Emerging Technologies 26
Defrost Failure • Results from supplying water hotter than 90⁰F to the outdoor unit which tricks the defrost into turning off • Designed as a water heater — not as a space or pool heater • Manufacturer immediately began working to solve the problem. Now has a UL listed version that defrosts up to 140⁰F supply temp Emerging Technologies 27
Matching Capacity to Load • Sites 4 and 6 were both unoccupied but heated during the same period in winter 2015 • At Site 4, design load is 21,061 Btu per hour — at Site 6 it is 6,226 • Heat pump capacity for both sites was 13 to 15 thousand Btu per hour depending on outdoor air temperature • Site 4 in McCall had sufficient capacity — heat pump plus backup — to meet design load (-16 °F) • During this test period the temperature at McCall plunged from 26 to -8 °F impacting load • Note the large difference in FEF Site OAT FEF 4 25 0.13 6 48 2.05 The very low FEF at Site 4 indicates the system did not function properly The solution is a larger heat pump Emerging Technologies 28
Tank Destratification • Occurs when the heat demand on the tank results in heat supply flow rates that cycle the storage tank making it all one temperature (at 4 GPM an 80 gallon tank cycles in 20 minutes) • Without temperature difference transcritical operation efficiency plummets • To maintain tank stratification: – Match load to heat pump output – For split systems use a larger tank in combined systems — 120 gallon is recommended – Return water to tank location closest to its temperature – Stop circulation when tank reaches bottom of hot water layer and allow heat pump too recover – Like Site 10 use lots of hot water which pulls cold water into the bottom of the tank — maintaining stratification Emerging Technologies 29
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