Residential Water Heater Efficiency

Standards:

Engineering Analysis

Jim Lutz

Lawrence Berkeley National Laboratory

Q11/

11/09/98 Engineering - Water Heaters 1 RI

RI

EE-RM-97-900 COMMENT 38EE
Modeling - Existing Baseline

*Electric Water Heaters

- 50 gallon rated volume

-EF = 0.858

- 4.5 kW input

- 1.5 inch insulation

* to meet minimum NAECA EF

- modeling fitting losses in WATSIM

* to match default fitting losses in TANK

* 1/8 in. insulation

* reduced conductivity and convection

1 1/09/98 Engineering - Water Heaters 2

EE-RM-97-900 COMMENT 38EE
Modeling - Existing Baseline

*Gas-fired Water Heaters

- 40 gallon rated volume

-EF = 0.5446

- RE= 75.5%

- 40,000 Btu/hr input

- 400 Btu/hr pilot light

- .981 inch insulation

- insulation conductivity same

as electric water heaters

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EE-RM-97-900 COMMENT 38EE
Modeling - Analytic Baseline

* Change blowing agent to HFC-245fa

* Insulation conductivity increased 3%

* Insulation thickness increased

- electric to 1.55 inches

- gas-fired to 1.00 inches

* No other changes

11/09/98 Engineering - Water Heaters

EE-RM-97-900 COMMENT 38EE
Simulation Modeling

* Tools

- WATSIM

* for electric water heaters

* developed by EPRI

- TANK

* for gas-fired water heaters

* developed by Battelle for GRI

* DOE test procedure

* National average energy prices

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EE-RM-97-900 COMMENT 38EE
Manufacturer Costs - Data Sources

* GAMA

- existing baseline

- most design options

* Minniear, West (consultants)

- sheet metal and foam insulation

- plastic tank

- side arm heater

- oil-fired water heaters

* Williams (Allied Signal)

- projected foam component costs

* Gilchrist (Perfection)

- heat traps

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EE-RM-97-900 COMMENT 38EE
Foam Component Costs

Components Fraction Component Total Cost Total Cost

% Cost (HCFC-141b) (HFC-245fa)

$/lb $/lb $/lb

blowing agent (HCFC-141b) 13% $1.50 $0.20 -

blowing agent (HFC-245fa) 13% $4.00 -$0.52

Isocyanurate 51% $075 $038 $0.3

polyols 31% $0.65 $0.20 $0.20

catalysts, refractants, etc. 5% $4.50 $0.23 $0.23

Total 100% $1.00 $1.32

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EE-RM-97-900 COMMENT 38EE
Cost for Insulation and Jacket

Electric Water Heaters

Existing Baseline Analytic Baseline

(HCFC-141b) (HFC-245fa)

Thickness Cost Thickness Cost

1.5 in. $11.64 1.55 in. $13.78

2.0 in. $19.86 2.0 in. $22.37

2.5 in. $24.94 2.5 in. $28.19

Cost includes foam, jacket and foam dams

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EE-RM-97-900 COMMENT 38EE
Cost of Design Options

Electric Water Heaters

Design Option Average Cost

Existing Baseline (HCFC-141b) (1) $125.56

Analytic Baseline (HFC-245fa) (2) $127.70

Heat Traps (metal) (1) $4.01

Heat Traps (plastic) (1) $4.01

2" Jacket Insulation (1)(2) $13.49

2.5" Jacket Insulation (3) $23.77

Insulate Tank Bottom (1) $30.37

Plastic Tank (3) $27.25

(1)- from GAMA

(2)- adjusted for HFC-245fa

(3)- from Minniear

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EE-RM-97-900 COMMENT 38EE
Markup

Electric Water Heaters

* Retail Price =$188.18

- from LBNL Water Heater Database

- average of 50 units

- 50 gallon, 5 year warranty, no extra features

- with 5.2% average sales tax

* Manufacturer Cost =$125.56

- from GAMA

- average of 4 manufacturers

- existing baseline model

* Markup 1.4987

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EE-RM-97-900 COMMENT 38EE
Installation Cost

Electric Water Heaters

Installation -$160.73

- from LBNL Water Heater Database

- average of 41 units

- 50 gallon, 5 year warranty, no extra features

- delivery, removal and permit fees included

* Same installation cost for all design options

11/09/98 Engineering - Water Heaters

EE-RM-97-900 COMMENT 38EE
Cost Efficiency Table

Electric Water Heaters

Design Options Energyt TotaTotl Annual Payback

Factor Manufacturer Installed Operating years

Cost * Cost ** Cost *** *

0 Existing Baseline 0.858 $125.56 $348.91 $390.75 NA

Oa Analytic Baseline 0.858 $127.70 $352.12 $390.75 NA

1 Oa + Heat Traps (plastic) 0.876 $131.71 $358.13 $383.66 0.85

2 1 + 2" Jacket Insulation 0.890 $145.20 $378.35 $378.15 2.08

3 1 + 2.5" Jacket Insulation 0.901 $155.48 $393.75 $374.22 2.52

4 3 + Plastic Tank 0.908 $182.73 $434.59 $372.01 4.40

5 3 + Insulate Bottom 0.908 $185.85 $439.27 $372.41 4.76

from data submitted by GAMA and consultants

** includes retail markup (1.49874) and installation cost

*** DOE test procedure, electricity price = 0.0787 $/kWh

**** payback = (change of installed cost) - (change of operating cost)

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EE-RM-97-900 COMMENT 38EE
Cost for Insulation and Jacket

Gas-fired Water Heaters

Existing Baseline Analytic Baseline

(HCFC-14 1b) (HFC-245fa)

Thickness Cost Thickness Cost

0.981 in. $8.66 1.000 in. $9.77

1.981 in. $17.17 1.981 in. $19.36

2.481in. $21.43 2.481in. $24.26

Cost includes foam, jacket and foam dams

11/09/98 Engineering - Water Heaters 13

EE-RM-97-900 COMMENT 38EE
Cost of Design Options

Gas-fired Water Heaters

Existing Baseline (HCFC-141b) (1) $137.61

Analytic Baseline (HFC-245fa) (2)(5) $173.72

Heat Traps (metal) (1) $3.32

Heat Traps (plastic) (1) $3.32

2" Jacket Insulation (1) (2) $16.56

2.5" Jacket Insulation (3) $28.01

Improve Flue Baffle (1) $6.47

Flue Damper (1)(4) $172.86

Side Arm Heater (RE=76%) (3) (4) $109.51

Side Arm Heater (RE=78%) (3)(4) $115.98

(1)- from GAMA (2)- adjusted for HFC-245fa

(3)- from Minniear (4)- w/ electronic ignition

(5)- w/ flammable vapor ignition resistant design

11/09/98 Engineering - Water Heaters 14

EE-RM-97-900 COMMENT 38EE
Markup

Gas-fired Water Heaters

* Retail Price $157.74

- from LBNL Water Heater Database

- average of 52 units

- 40 gallon, 5 year warranty, no extra features

- with 5.2% average sales tax

* Manufacturer Cost =$137.61

- from GAMA

- average of 4 manufacturers

- existing baseline model

* Markup 1.1463

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EE-RM-97-900 COMMENT 38EE
Installation Cost

Gas-fired Water Heaters

Installation $159.52

- from LBNL Water Heater Database

- average of 48 units

- 40 gallon, 5 year warranty, no extra features

- delivery, removal and permit fees included

- essentially same as electric water heaters

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EE-RM-97-900 COMMENT 38EE
Extra Installation Costs

Gas-fired Water Heaters

* installing Type-B vent connector

- for increased RE (from 76% to 78%)

- 51% households

- $54.01 average cost

* adding electricity

- 32% households require new circuit

- $33.90 average cost

* cost data from GRI report

11/09/98 Engineering - Water Heaters 17

EE-RM-97-900 COMMENT 38EE
Design Option Combinations

Gas-fired Water Heaters

Selected Design Option Combinations Design Option Combinations Not Selected

Analytic Baseline

+Flue Damper ,,___ _ _-iew/lIID

I F

+ Heat Traps - + 2" insulation + Se Am

" - ""---- , + Side Arm Heater 1 w/llD&RE=78%

+ 2.5" insulation -- -+ Improve Flue

I __ '__

____________I ' H Baffle

+Side Arm Heater _ + Flue Damper

w/llD & RE =76% . w I.. IID

+ Improve Flue + Improve Flue

Ip Baffl+ e Baffle Baffle

11/09/98 Engineering - Water Heaters 18

EE-RM-97-900 COMMENT 38EE
Cost Efficiency Table

Gas-fired Water Heaters

Design Options Energy Total Total Annual Payback

Factor Manufacturer Installed Operating years

Cost * Cost ** Cost ***  

0 Existing Baseline 0.545 $137.61 $317.26 $166.34 NA

Oa Analytic Baseline 0.544 $173.72 $358.65 $166.34 NA

1 Oa + Heat Traps (plastic) 0.554 $177.04 $362.45 $164.71 2.31

2 1 + 2" Jacket Insulation 0.580 $193.60 $381.44 $159.64 3.42

3 1 + 2.5" Jacket Insulation 0.587 $205.05 $394.56 $158.60 4.63

4 3 + Side Arm Heater 0.662 $314.56 $553.99 $133.61 5.97

5 2 + Improve Flue Baffle 0.595 $200.07 $442.87 $154.64 7.19

8 from data submitted by GAMA and consultants

**  includes retail markup (1.1463) and installation cost

*** DOE test procedure, electricity price = 0.0787 $/kWh and gas price = 5.82 $/MMBtu

**** payback = (change of installed cost) - (change of operating cost)

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EE-RM-97-900 COMMENT 38EE
Request for Stakeholder Comments

* Baseline and incremental manufacturing

costs for all design options

* Retail prices and installation costs

* Markup

* Maintenance Costs

11/09/98 Engineering - Water Heaters 20

EE-RM-97-900 COMMENT 38EE
Modeling - Design Options

electric water heaters

Design Option Descriptive Parameters Analytic Design Option

Baseline Values

Metal Heat Traps Feed-through Insulation Conductivity 0.000240 0.000240

Btu/ft-min-°F Btu/ft-min-°F

Feed-through Natural Convection 0.185 0.063

Btu/hr-°F Btu/hr-°F

Plastic Heat Traps Feed-through Insulation Conductivity 0.000240 0.000240

Btu/ft-min-°F Btu/ft-min-°F

Feed-through Natural Convection 0.185 0.063

Btu/hr-°F Btu/hr-°F

2 Inch Insulation Insulation Thickness 1.55 in. 2.00 in.

2.5 Inch Insulation Insulation Thickness 1.55 in. 2.50 in.

Insulate Tank Bottom Support Ring Conductivity .40 0.000472

Btu/ft-min-°F Btu/ft-min-°F

Bottom Insulation Thickness 0.75 in. 1.5 in.

Bottom Insulation Conductivity 0.000333 0.000240

Btu/ft-min-°F Btu/ft-min-°F

Plastic Tank Tank Wall Thickness 0.063 in. steel: 0.0853 in.

plastic: 0.126 in

Tank Wall Conductivity .40 0.0018

Btu/ft-min-°F Btu/ft-min-°F

Support Ring Conductivity 0.40 0.000236

Btu/ft-min-°F Btu/ft-min-°F

Bottom Insulation Thickness 0.75 in. 1.0 in.

Bottom Insulation Conductivity 0.00033 0.000240

Btu/ft-min-°F Btu/ft-min-°F

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EE-RM-97-900 COMMENT 38EE
* *

Modeling - Design Options

gas-fired water heaters

Design Option Descriptive Parameters Analytic Design Option

Baseline Values

Metal Heat Traps Heat Traps 0 1

Plastic Heat Traps Heat Traps 0 -

2 Inch Insulation Insulation Thickness 1.000 in. 1.981 in.

2.5 Inch Insulation Insulation Thickness 1.000 in. 2.481 in.

Improved Flue Bale Excess Combustion Air 42.0 34.0

Flue Baftle Eftectiveness Multiplier 2.000 2.200

Electronic Ignition Pilot Input 400 Btu/hr 0 Btu/hr

(intermittent pilot

ignition ignition system) system) On-cycle _ __ 

Power Consumption _ 0 W 15.7 W

Off-cycle Power Consumption 0 W 0.4 W

Electromechanical Off-cycle Pressure Loss Coefficient12.4047 156

Flue Damper Tprt-cycle Power Consumption W 5.0 W

Side Arm Heater (1) Metal Tank, 2" insulation, EF = 0.655 RE = 76%

Plastic heat traps, IID

Metal Tank, 2" insulation, EF = 0.668 RE = 78%

Plastic heat traps, IID

Plastic Tank, 2" insulation, EF = 0.662 RE = 76%

Plastic heat traps, IID

Plastic Tank, 2" insulation, EF = 0.675 RE = 78%

Plastic heat traps, IID

(1) Side Arm Heater not modeled with TANK

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