Commercial Gas Water Heaters in the Real World

Transcription

1 Commercial Gas Water Heaters in the Real World Case Study Presented at the 2019 ACEEE Hot Water Forum Jeff Rigotti Northwest Energy Efficiency Alliance Jordan Pratt Energy 350

2 AGENDA Introductions ICE Heat Pump Trial Gas Absorption Heat Pump Replacement Design Challenges Next Steps 2

3 NEEA: NATURAL GAS COLLABORATIVE GOAL To accelerate the development and market adoption of efficient natural gas products, practices and services resulting in INCREASED CONSUMER CHOICES and INCREASED EFFICIENCY OF NATURAL GAS USE in the Northwest. 3

4 28 person firm based in Portland, OR Energy Efficiency Program Deployment & Support Building Tuning/RCx/SEM Energy Studies Research & Evaluation 4

5 CAPITAL MANOR Baseline Equipment Capacity (kbtu/hr) Nominal Efficiency Measured Efficiency HHW Boiler 1,900 80% 74% DHW Heater % 68% 5

6 INTERNAL COMBUSTION ENGINE HEAT PUMP 315,525 Btu/hr COP = ,015 Btu/hr Image Source: Tecogen (values updated to field trial results) 6

7 AS-BUILT SCHEMATIC 7

8 INSTALLATION 8

9 PERFORMANCE RESULTS Overall Average Capacity 40 F 75 F 40 F Ambient 75 F Ambient COP (Btu/hr) Ambient Ambient (Btu/hr) (Btu/hr) , , , F 140F 160F Field Results (150F Set Point) 1.6 COP Ambient Temp ( F) 9

10 ECONOMIC RESULTS NWN Schedule: Energy Cost: 32CSF $ /therm Baseline Annual Gas Consumption (Therms) Performance Gas Consumption (Therms) Annual Gas Savings (Therms) 28,759 17,409 11,350 10

11 ILIOS FAILURE Contained Fire No Safety Issues Forensic Investigation Unit Unrecoverable 11

12 REPLACEMENT HEAT PUMP DHW and HHW Efficiency > 120% Fit Existing Pad Image Source: Image Source: Utilize Existing Heat Exchanger System Image Source: 12

13 GAS FIRED ABSORPTION HEAT PUMP HW up to 140 F Efficiency up to 129% Nominal Heat Output: 123,500 Btu/hr Modular and Scalable Image Source: 13

14 CHALLENGES TO OVERCOME Robur: max return temperature of 122 F Max hot water supply temperature 140 F 14

15 DOMESTIC HW LOOP 15

16 MINIMIZING RETURN TEMPERATURE TO GAHPS Installed VFDs on DHW loop pumps Replaced DHW circ pump with ECM Aggressively lowered HHW reset Temp 16

17 DHW RETURN TEMPERATURE WAS SIGNIFICANTLY REDUCED DHW Return Temperature 140 Before: 122 F 120 Temperature ( F) 100 After: 112 F VFD & ECM Smart Pump Installed

18 INSTALLED AND COMMISSIONED 18

19 GAHP RETURN TEMPERATURE HAS HELD COMFORTABLY BELOW 122 F Glycol Supply/Return Temperature Glycol Supply: 129 F Glycol Return to GAHPs: 111 F GAHP Glycol Return Temp GAHP Supply Temp 19

20 PRELIMINARY PERFORMANCE Daily COP GUE = 1.27 (Gas Input Only) COP = 1.23 (Includes GAHP Electric Input) COP_avg COP_avg /12 2/14 2/16 2/18 2/20 2/22 2/24 2/26 2/28 Daily COP vs. Ambient Air Temperature Average Outside Air Temp ( F) 20

21 Monitor GAHP performance through end of 2019 NEXT STEPS Analyze annual performance Report performance results along with economic findings 21

22 THANK YOU! Questions? Jeff Rigotti Northwest Energy Efficiency Alliance Jordan Pratt Energy

23 APPENDIX

24 Gas Absorption Cycle Image Source: 24

25 ICE HEAT PUMP SYSTEM PERFORMANCE Daily Gas (Therms) Baseline System ICE Heat Pump System Gas Input vs. HDD_ HDD_65 ( F-day) 25

26 ICE HEAT PUMP SYSTEM PERFORMANCE Therms/day Average Daily Temp ( F) DHW Heaters HHW Boiler Ilios Heat Pump Modeled Work by HHW Boiler Modeled Work by DHW Heaters 26

27 DESIGN SCHEMATIC 27

28 ECONOMIC RESULTS NWN Schedule: Energy Cost: 32CSF $ /therm Baseline Annual Gas Consumption (Therms) Performance Gas Consumption (Therms) Annual Gas Savings (Therms) Annual Gas Savings ($) Annual Maintenance Costs ($) Total Project Costs Simple Payback (Years) 28,759 17,409 11,350 $6,483 $2,167 $138, Simple Payback (Years) Maintenance Excluded Payback (Years) Low Gas Price Payback (Years) Medium Gas Price Payback (Years) High Gas Price Payback (Years) Optimal Scenario Payback (Years)

29 PERFORMANCE RESULTS F 140F 160F Field Results (150F Set Point) 1.6 COP Defrost Ambient Temp ( F) 29

30 ADDED VFD TO DHW PUMPS & REPLACED CIRCULATOR PUMP WITH ECM SMART PUMP 30