-Fired Water Heater

E n gineering Analysis-Overview :::::::::::::::::::::::::::::::::::::::::::::: ................ : ............

I David Winiarski

Pacific Northwest National Laboratory

. . ....... ..

i: * ^

EE-RM-97-900 COMMENT 38FF
-Fired Water Heater

ineering Analysis Methodology

- Key Notes:

· No readily available oil fired simulation model

* Design option performance based on engineering

calculations for energy loss, assumptions about

achievable performance, and in one case,

component level results from TANK software

* Water Heater Analysis Model (WHAM) used for

energy consumption calculations

* Cost data obtained from industry consultants and

limited phone surveys

EE-RM-97-900 COMMENT 38FF
Aalytic Model Assumptions M M

: 32 gal. Intermittant Ignition

Nominal Volume

90,000 Btu/hr Energy Factor

Fuel Input Rate (EF) = 0.529

282 Watts Recovery Efficiency

Electric Consump. (RE) = 0.75

1 in. Foam Insulation Standby Heat Loss Coef

(HFC-245fa) (UA) = 14.494 Btu/hr-F

EE-RM-97-900 COMMENT 38FF
Ds7ign Mlodifications Considered

: Heat Traps

* Increased Jacket Insulation

i Improved Flue Baffle

* Increased Heat Exchanger Surface

Area

m Interrupted Ignition

EE-RM-97-900 COMMENT 38FF
.E ergy Calculations

l WHAM equation used to estimate energy consumption

~ ? vol.dens.Cp,(Ttadl- Tin) 1 o(T- l b) T

Qi= 1- + 24.UADo(Ttank- Tamb)

`OE POtDOE

* 24- Loss_continuous + (24-Burner Operating

Hours) Loss_flue_off + (Burner Operating Hours

Loss_flue_on) = Qdraw/EF- Qdra

* Loss_continuous + Loss_flue_on = Input (1 - Recovery

Efficiency)

EE-RM-97-900 COMMENT 38FF
ling Techniques

Analytic Model Change insulation to 245fa based

foam - performance same as

B; g ,baseline model

ei I1 Analytic Model + Heat Reduction in UA from TANK

traps simulation

.2 #1 + 2 in. insulation Reduction in continuous losses

I ________from tank

3 #2 + Improved Flue Recovery Efficiency raised to 0.78

Baffle

4 #2 + Increased Heat Recovery Efficiency raised to 0.82

Exchanger Area

5a #3 + Interruptible Ignition Assume 20 sec. igniter on-time

per firing

5b #4 + Interruptible Ignition Assume 20 sec. igniter on-time

per firing

EE-RM-97-900 COMMENT 38FF
' ergy of Design lmpact Opions

, DDesign EF RE UA

___:~f~ __________ _________ (Btu/hr-F)

iO 0 Existing 0.529 0.750 14.494

Oa Analytic model 0.529 0.750 14.494

1 Oa + Heat Traps 0.539 0.750 13.595

2 1 + 2 in. Foam Insulation (tank only) 0.555 0.751 12.241

3 2 + Improved Flue Baffle 0.576 0.780 11.786

4 2 + Increased Heat Exchanger Area 0.606 0.820 11.216

5a 3 + Interrupted Ignition 0.580 0.785 11.708

5b 4 + Interrupted Ignition 0.610 0.825 11.142

EE-RM-97-900 COMMENT 38FF
st Impact of Design Option

Design MFG Cost Retail Annual Simple

Pricea' b Energy Payback

Cost (yrs)

0 Existing $139.25 $445.60 $217.94 ---

Oa Analytic model $140.27 $448.86 $217.94

1 Oa + Heat Traps $144.94 $463.81 $213.96 3.7

2 1 + 2 in. Foam Insulation $155.89 $498.85c $207.80 6.7

3 2 + Improved Flue Baffle $193.19 $618.210 $200.08 10.5

4 12 + Increased Heat Exchanger Area $259.14 $829.25c $190.40 14.5

5a 3 + Interrupted Ignition $210.69 $674.21C $196.41 11.2

5b 4 + Interrupted Ignition $276.64 $885.25c $186.64 14.5

a A markup of 3.2 was applied to manufacturing cost to estimate retail price.

b Base burner cost not included.

c An additional $18.25 per installation was added to the installation expense to

account for the use of a longer blast tube and nozzle on 50% of the burners. This

additional cost must be added to the retail price to calculate the simple payback

EE-RM-97-900 COMMENT 38FF
?Ii-specific areas where DOE would

~ ,e comments

* Use of additional insulation with existing

burners.

| * Baseline manufacturing cost and

" manufacturer-to-retail markup assumed

m Manufacturing cost estimates for design

options

* Industry impact of specific design options

EE-RM-97-900 COMMENT 38FF