Field Study of an Intelligent, Networked, Retrofittable Water Heater Controller

Field Study of An Intelligent, Networked, Retrofittable Water Heater Controller

ACEEE Hot Water Forum - Portland, OR

Ben Schoenbauer CEE & David Kalensky, GTIFebruary 2017

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Acknowledgements

• This project is supported in part by grants from the Minnesota Department of Commerce, Division of Energy Resources through a Conservation Applied Research and Development (CARD) program

• Gas Technology Institute is the project lead

• Aquanta is the project’s industry partner

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Project Goal

To validate the field performance and energy savings of an innovative, intelligent, networked water heater controller for residential and small commercial storage water heaters for potential inclusion within Minnesota’s Technical Reference Manual (TRM) and as a program measure within Conservation Improvement Program (CIP) portfolios.

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Methodology

• Install 30+ controllers• Mix of gas and electric• Mix of hot water loads• Mix of inlet water conditions

• Detailed M&V on 10 sites• Detailed Instrumentation w/ high resolution data collection• Alternating mode analysis

• Evaluating different control algorithms

• Analysis of controller• Assess installation• Characterize energy performance• Characterize impact on energy use profile • Assess the impact on hot water delivery• Evaluate the devices measurement capabilities

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Installation and Validation

• Tank Sensor through TMP Valve

• Control Units• Electric• Gas Valve

• Additional Sensors• Leak Detection• Water Inlet Temperature

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Installation and ValidationSite Fuel Type

Water Heater

SizeWater Heater Unit Hot Water

Use (GDP)Number of Occupants

Energy Factor

0.95

0.90

0.91

0.90

0.70

0.62

0.62

0.70

0.67

0.95

31.3

36.0

45.6

31.6

4

2

2

4

2

2

1

5

8

4

36.2

18.1

34.0

52.5

35.0

24.6

Electric 50 AO Smith ECT 52 200

d216_gas_04 Gas 50 AO Smith GPVL 50 200

d216_elec_02 Electric 50 Marathon MR 502 45 B

d216_elec_05 Electric 50 Bradford White M250T6DS-1NCWW

d216_elec_04

d216_elec_03 Electric 50 Reliance 606 650 DOCT

d216_elec_01 Electric 50 Rheem PROE 50 T2 RH95

d216_gas_05 Gas 40 Rheem 43V P40 SE2

d216_gas_03 Gas 50 AO Smith FPSH 50 250

d216_gas_02

d216_gas_01 Gas 50 American Standard PCG6250T403NOV

Gas 40 Rheem XG40S09HE38U0

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Installs

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Field Sites

Figure 1 33 Field Sites in Minnesota (22 Natural Gas; 11 Electric)

Figure 2 16 Field Sites in the Greater Minneapolis / St. Paul Area (12 Natural Gas; 2 Electric)

Figure 3 9 Field Sites in the Duluth Area (4 Natural Gas; 5 Electric)

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M&V Instrumentation

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Preliminary Performance

• Energy Savings

• Reduced stand-by or idle loses• Lower tank temperatures (through reducing set point)• Eliminate unnecessary reheats (through lock out)

• Reduction of over heating (through reducing set point)

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Supply Water Temperature

10 20 30 40 50 60 70 80105

110

115

120

125

130

AI_2AI_1Base_2Base_1

Daily Hot Water Use [GPM]

Deliv

ered

Wat

er T

empe

ratu

re

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Energy Use Profile

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Inlet Water Temperature

7/19/16 9/7/16 10/27/16 12/16/16 2/4/17 3/26/1730

35

40

45

50

55

60

65

70

75

80

d216_gas_02

d216_gas_01

d216_gas_03

d216_gas_04

d216_gas_05

d216_elec_01

d216_elec_02

d216_elec_03

d216_elec_04

d216_elec_05

Inle

t Wat

er T

empe

ratu

re [F

]

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Energy Use per Gallon of Hot Water

40 45 50 55 60 650

200

400

600

800

1000

1200

BaseLinear (Base)Con-trolled

House Inlet Water Temp

Ener

gy U

se p

er G

allo

n (B

tu/g

al)

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Energy Use per Gallon

• Btu per gallon is lower with the controller active at all 10 sites

• Energy per gallon is reduced up to 15%• Energy use per gallon is NOT water heating savings

• If the water temperature has changed the flow profile may have changed

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Hot Water Load

40 45 50 55 60 65 700

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

BaselineLinear (Base-line)

House Inlet Water Temperature [F]

Hot W

ater

Del

iver

ed (

btu/

day)

This site as the longest monitoring time had shows

~10% savings

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Controller as a Measurement Device

• Direct measurement • Change in total energy• Current sensing (on/off)• Power usage (kWh)• Cold water inlet temperature (F/C)

• Derived values from data:• Water heater energy input• Water heater energy output (load)• standby loss• Hot water usage • Hot water available

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Conclusions

• Smart controllers can • control water heater usage profiles• eliminate unnecessary reheats• reduce energy use for water heating• Measure, calculate and provide data and information to

occupants

• Monitoring through the summer 2017• Project completion in fall 2017

Future

Water Heater Size Installed M&V

Natural Gas 40 Gallon 13 2

50 Gallon 9 3

Electric40 gallon 1

50 gallon 9 5

80 gallon 1

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Project objectives

1. validate the time and ease of the installation procedure;2. evaluate the reliability of the technology and fidelity of its data output;3. establish baseline water heating energy and water usage in a residential

and potentially small commercial context;4. measure the energy savings resulting from the technology's advanced

controls;5. measure any impact on end-users' subjective experience;6. evaluate the cost effectiveness of the technology in the context of a

broad deployment; and7. quantify potential utility demand side management applications.

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Variable Unit DescriptionDate-Time Stamp Date and Time Realtime 1 second data

Energy Stored kWh Energy available for use KwhWater Temp In °C Water temperature into tank

Water Temp Out °C Water temperature out of tank Energy In kWh Electric and/or natural gas used to replenish and reheat

Standby Loss kWh Jacket and Flue loss Energy Out kWh Energy utilized (hot water)

Hot Water Used Gallons Calculated from Energy OutHot Water Avail Gallons Calculated from Energy Stored

Energy Saved kWh Calculated from prevented reheatsHot Water Flow Gallons/ Minute Water draw over time

Standby Rate kWh/ Minute Jacket and flue loss over timeEnergy In Rate kWh/ Minute Replenish and reheat over time

Water Heater Controller Data AnalysisObjective: Analyze data from the water heater controller data to assess how variables used in control algorithms contribute to optimizing energy savings. This results will be used in a guidance document for utilities in evaluating smart water heater controllers.

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BTU per Gal Baseline Controlled

Gas_01 939 836 11%Gas_02 1430 1226 14%Gas_03 975 955 2%Gas_04 692 659 5%Gas_05 Elec_01 579 557 4%Elec_02 625 589 6%Elec_03 680 642 6%Elec_04 580 568 2%Elec_05 611 592 3%

Energy Use per Gallon of Hot Water

• Note these are NOT total energy savings. • This the reduction in energy to heat a

single gallon. • Water at lower temps may require larger flow

rates (ie mixing showers)

40 45 50 55 60 650

10

20

30

40

50

60

Base Controlled

House Inlet Water Temp

Hot W

ater

Vol

ume

(GPD

)