Monitoring Field Performance of Residential Geothermal Heat Pumps

Transcription

1 Monitoring Field Performance of Residential Geothermal Heat Pumps Brought to you by Manitoba Hydro s Earth Power Program Presented by: Rob Andrushuk, C.Tech. Date: November 18, 2008

2 Today s presentation topics Part 1 Why monitor heat pump performance? Part 2 What information did we gather? Part 3 How did we monitor the seasonal efficiency of a ground source heat pump? Part 4 Who, when, and where? Part 5 Results

3 Part 1: Why monitor heat pump performance?

4 Why monitor heat pump systems? Manitoba Hydro promotes ground source heat pump technology and the public looks to us for energy saving information

5 Why monitor heat pump systems? ARI certified efficiency information already available, but is for steady state efficiency at set operating conditions and does not include all system losses Require better information on the actual efficiencies of heat pumps installed in our climate Require information on desuperheater performance in a heating dominated climate

6 Other possible benefits Determine best practices: Loop design Heat pump sizing Desuperheater Duct design

7 Part 2: What information did we gather?

8 System seasonal efficiency Seasonal Coefficient of Performance (SCOP) of the heat pump over a heating season Seasonal Energy Efficiency Ratio (SEER) of the heat pump over a cooling season Domestic hot water energy savings provided by the desuperheater

9 Part 3: How did we monitor the seasonal efficiency of a ground source heat pump?

10 Equipment Energy meter 8 channel logger (digital, analog, and amperage)

11 Power consumption Data logger monitors power consumption of: Whole house Heat pump compressor Fan Ground loop pump Auxiliary heater Desuperheater pump Domestic water heater

12 Equipment Current transformers

13 Energy provided from or to the loop Temperature probes are installed on the loop supply and return to the heat pump A flow meter is installed on the loop The temperature difference is logged when the heat pump is operating Energy = mass flow rate x specific heat x temperature difference

14 Equipment Flow meter Resistance Temperature Detectors (RTD)

15 Hot water heater energy supplied to home Monitor hot water consumption and temperature difference Add stand-by losses for water heater Utilized water meter with pulser and temperature probes

16 Part 4: Who, when, where?

17 Who, when, where? 10 single detached residential homes Monitored since 2006 Still monitoring most sites Located in various regions of Manitoba Various heat pump manufacturers and installers Various loop designs All with desuperheaters

18 Overview of monitoring sites (noted in red)

19 Part 5: Results

20 2007 Heating Season SCOP of 2.8 (2.9 without auxiliary heat) Average heat pump operated 2,242 hours with 8,664 starts 5,719 Degree-Days (average year is 5,778 DD) Ground loop provided an average of 17,409 kwh of heat Auxiliary heater provided 1% of annual heating

21 Chart #1: Field Monitored COP Versus Manufacturer's CSA/ARI COP Weighted House # Average Field Monitored SCOP CSA/ARI COP Rating SCOP or COP

22 Weighted Average Annual Entering Water Temperatures (degrees Fahrenheit) Well to Well Lake Loop Horizontal Loop Vertical Loop Horizontal Loop Horizontal Loop Vertical Loop Vertical Loop Horizontal Loop Vertical Loop Average Loop Type Temperature (F)

23 Minimum Entering Water Temperature Average Lake Loop Horizontal Loop Vertical Loop Horizontal Loop Horizontal Loop Vertical Loop Vertical Loop Horizontal Loop Vertical Loop Ground Loop Type Well to Well Temperature (F)

24 Compressor Consumption per 10,000 btu of heat delivered Electricity draw (Watts) Average House #

25 Fan Power (Heating) average ARI/CSA House # 2 1 Watts /10,000 btu heat output

26 Ground Loop Pump Power (Heating) average ARI/CSA House # Watts / 10,000 btu of heat delivered

27 2007 Cooling Season Actual average SEER of 13.5 Average CSA/ARI EER rating of 16.2 Average heat pump operated 216 hours with 1,102 starts 2007 Degree-Days Cooling was 199 (average year is 186 DD Cooling) Average heat pump consumed 791 kwh of electricity 2007 heating/cooling ground load ratio was 5 to 1

28 Actual SEER in 2007 versus ARI/CSA EER Rating Weighted Average House # SEER CSA/ARI EER Rating SEER/EER

29 Domestic hot water (DHW) Average savings of 18% 86% of the savings occurred in heating mode Reduced average annual electricity usage by 613 kwh Two desuperheater pumps failed during the test period Domestic hot water heaters operated at temperatures lower than manufacturer s recommendations Water heater temperature required adjustment in the spring and fall when only one storage tank was used

30 Net Annual DHW Energy Savings Energy Saved (kwh) House # Average

31 Questions? Personal contact information: Rob Andrushuk, C.Tech. Manitoba Hydro Mechanical Systems Specialist Phone: (204)