MEASUREMENT OFWATER HEATER

EFFICIENCY

MEASURE EFFECTIVENESS

• APPLICATION – RETIREMENT VILLAGE

• CURRENT SYSTEM (CONTROL)

• CONTROLLER (NEW SYSTEM)

• ACCOUNT FOR USE PATTERNS

CONSTRAINTS

• NO LOSS OF HOT WATER SERVICE

• TWO WEEKS FOR EXPERIMENT

COLD WATERSUPPLY

WATERMETER

GASMETER

SOLENOID

TO SPACEHEATING

GAS SUPPLY WATERHEATER

HOT WATERSUPPLY

LARGE

CONSUMPTION

COLD WATERSUPPLY

WATERMETER

GASMETER

SOLENOID CONTROLLER

TO SPACEHEATING

GAS SUPPLY WATERHEATER

CONCERNS

• GAS METER MEASURED BOTH HOT WATER AND SPACE HEATING USAGE

• WAS BURNER CONSUMPTION RATE CONSTANT?

• HOW TO ACCOUNT FOR GREATER USAGE ON MONDAY AND FRIDAY?

• HOW TO ACCOUNT FOR STANDBY LOSSES?

GAS METER MEASURED BOTH HOT WATER AND SPACE HEATING USAGE

MONOTOR TIME THAT GAS SOLENOID IS OPEN.

COLD WATERSUPPLY

WATERMETER

GASMETER

TIMER

SOLENOID CONTROLLER

TO SPACEHEATING

GAS SUPPLY WATERHEATER

WAS BURNER CONSUMPTION RATE CONSTANT?

CALIBRATE BURNER GAS CONSUMPTION

• MEASURE HOT WATER GAS CONSUMPTION WITH SPACE HEATING OFF

• REPLICATE

WEEKLY USAGE

0

100

200

300

400

500

600

700

800

SUNDAY TUESDAY THURSDAY SATURDAY

HOW TO ACCOUNT FOR GREATER USAGE ON MONDAY AND

FRIDAY?

USE BLOCKING

• INSTALL CONTROLLER• ACTIVATE FIRST WEEK• DEACTIVATE SECOND WEEK

HOW TO ACCOUNT FOR STANDBY LOSSES?

• USE BLOCKING IN TIME

• EXAMINE EFFECT OF USAGE

RESULTS

CONTROLLER OFF

CONTROLLER OFF

DAY GAS WATER GAS/WATERSCF GAL SCF/GAL

1 3515 3020 1.1642 3356 2830 1.1863 3745 3420 1.0954 3437 3050 1.1275 3617 3300 1.0966 3443 3085 1.1167 3260 3005 1.085

BALANCE CHECK

REASONABLE RESULTS?

CHECK CONSERVATION OF ENERGYEQUATION:

Q

Qout

in

BALANCE CHECK

S E N S I B L E H E A T O F W A T E R P E R G A L L O N :

Qm C T

Vo u tp

Q C To u t p

H E A T I N G V A L U E O F F U E L :

Q V H vi n *

CONTROLLER OFF

CONTROLLER OFF

DAY GAS WATER GAS/WATERSCF GAL SCF/GAL

1 3515 3020 1.1642 3356 2830 1.1863 3745 3420 1.0954 3437 3050 1.1275 3617 3300 1.0966 3443 3085 1.1167 3260 3005 1.085

CALCULATION

Q SCFBtu

SCFin 1164 1000. *

galBtuQin /1164

CALCULATION

Qlbm

gal

Btu

lbm FFout

8 32 1 150 55. * * ( )

QBtu

galout 792

CALCULATION

68%

CONTROLLER ON

CONTROLLER ON

DAY GAS WATER GAS/WATERSCF GAL SCF/GAL

1 3286 3175 1.0352 3247 3370 0.9643 2907 2860 1.0164 3559 3625 0.9825 2672 2550 1.0486 2867 2865 1.0017 3289 3380 0.973

CONTROLLER OFF CONTROLLER ON

DAY GAS WATER GAS/WATERDAY GAS WATER GAS/WATERSCF GAL SCF/GAL SCF GAL SCF/GAL

1 3515 3020 1.164 1 3286 3175 1.0352 3356 2830 1.186 2 3247 3370 0.9643 3745 3420 1.095 3 2907 2860 1.0164 3437 3050 1.127 4 3559 3625 0.9825 3617 3300 1.096 5 2672 2550 1.0486 3443 3085 1.116 6 2867 2865 1.0017 3260 3005 1.085 7 3289 3380 0.973

COUNT 7 AVG 1.124 COUNT 7 AVG 1.003CHAV. 1.8 ST.DEV. 0.038 CHAV. 1.8 ST.DEV. 0.032

OUTLIER MAXIMUM 1.390 OUTLIER MAXIMUM 1.226OUTLIER MINIMUM 0.858 OUTLIER MINIMUM 0.779

t-TEST

OFF ON t-Test: Two-Sample Assuming Equal Variances

GAS/WATERGAS/WATER Variable 1 Variable 2SCF/GAL SCF/GAL Mean 1.124143 1.002586

1.164 1.035 Variance 0.001444 0.0010181.186 0.964 Observations 7 71.095 1.016 Pooled Variance0.0012311.127 0.982 Hypothesized Mean Difference01.096 1.048 df 121.116 1.001 t Stat 6.4813361.085 0.973 P(T<=t) one-tail1.51E-05

t Critical one-tail1.782287P(T<=t) two-tail3.02E-05t Critical two-tail2.178813

EFFECT OF WATER USAGE

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.2

2000 2500 3000 3500 4000

WATER CONSUMPTION

GA

S C

ON

SU

MP

TIO

N

OFF

ON

CONCLUSIONS

• CONTROLLER REDUCES GAS CONSUMPTION BY 11%

• DIFFERENCE IS STATISTICALLY SIGNIFICANTLY

• GAS CONSUMPTION PER GALLON OF HOT WATER REDUCES WITH GREATER CONSUMPTION