Heating Cost for 5000 Gallons of Water at 100o T

$32.80

85%

90%

80%

$30.87$29.15

Thermal Efficiency

Daily Operating Costs @ $0.63/Therm

“What Happens to Water When Heated”

Heated water becomes more corrosive...

More electrically conductive...

Expels dissolved gases...

Precipitates dissolved solids

85% of water in USA contains dissolved minerals

Hardness - Calcium & Magnesium (grains/gallon)

Total Dissolved Solids - All other minerals (mgl or ppm)

Pounds of Lime Deposited vs.... Temperature and Water Usage

0

30

60

90

120

150

180

210

0 300 900 1500 2100 2700 3300 3900WATER USAGE IN GALLONS PER DAY

PO

UN

DS

OF

LIM

E D

EP

OS

ITE

D

PE

R Y

EA

R

180oF

170oF

160oF

150oF

140oF

120oF

Engineering Considerations

Heat Transfer Surface

Copper

Combustion Process

Tank-Type Water Heaters

Extremely Susceptible to Scale -

Minimal Velocity

Thin construction

Low Thermal Efficiency

Short life

Scale Accumulation vs. Efficiency

Te

mp

era

ture

of

flu

e g

as

Distance

Fireside

Waterside

Heat Transfer Surface

Scale buildup

without scale

with scale

Operating Costs of a Commercial Water Heater

$$

1/4”3/8”

1/2”

38%

5/8”

48%

60%

74%

Source: Engineered Systems May/June 1988

Efficiency Loss % Scale Accumulation

in Inches

The Energy Robber!

Original Price vs. Long Term Cost

Decrease inThermalEfficiency

5%

10%

7.5%

6% 9.3% 12.8%

Increase in Fuel Cost for Life of Product

How to Control Scale The rate of scaling increases with temperature and usage.

In water tube-type equipment, this can be offset by increasing the water flow over the heat transfer surfaces, as this reduces the tube surface temperatures.

The turbulence of the flow, if high enough, works to keep scale that does precipitate off the surface.

Water Heating Equipment Design Goals

Make the Heating Surface Self Cleaning

Allow Room for Scale and Sediment to Fall Out

Incorporate a Means to Clean out Sediment

Lower the Heat Flux Rates

Circulating Tank Concept(Separate Water Heater and Tank)

Flexibility in Equipment Selection

Equipment Longevity

Continued Efficiency

Component Serviceability

Ease of Installation

Ease of Maintenance

High Efficiency Circulating Tank Water Heater

ScrubbingAction

Copper-fin UnitCopper-fin UnitStorageStorage

TankTank

ContinuousContinuousPumpPump

Copper-Fin Heat Exchanger

Near Perfect Heat Transfer Surface

Thermal Conductivity Higher Than Steel/Cast Iron

More Surface Area

Corrosion Resistant

Proven Heat Exchanger Design

Copper Heat Exchanger Principle

Controlled velocity scouring action Constant temperature monitoring Impervious to thermal shock Low water content Low standby loss

Heat Exchanger Construction

ASME Code Section IV 160# working pressure, 240# test

pressure “O” Ring and Gasketless construction Straight tube, 7/8” inside diameter,

balanced flow

“Straight-Tube” vs. “Coil-Type”

Maintenance

Deliming Kits and Tees

Pressure Drop

Serviceability

Continued Efficiency

Continued Efficiency

85% 85% 85% 85%85%

41%

50%

63%

78%

67%

0%

20%

40%

60%

80%

100%

START-UP 1 YEAR 2 YEARS 3 YEARS 5 YEARS

TH

ER

MA

L E

FF

ICIE

NC

Y

SCRUBBING NON-SCRUBBING

EFFECTS OF SCALING ON EFFICIENCYEFFECTS OF SCALING ON EFFICIENCY

Energy Savings

Benefits of Scrubbing vs Non-Scrubbing Water Heater Design

Equipment Longevity

Ease of Maintenance

Continued Efficiency

What vent options are available?

Conventional - Category I Side-Wall - Category III & IV Direct Vent Sealed Combustion - Category

I, III, & IV Outdoor

Thank You For Your Time !!