Energy and Maintenance Savings with ScaleSafe
Background on Scale Buildup
Water is used in a wide range of commercial applications. Each day businesses
and facilities heat water to serve the needs of their customers and patrons. Each year a
significant portion of their overhead is allotted to the fuel required to heat water, and
every day that allotment becomes slightly larger. However, most users do not realize how
much money they lose each year due to the negative by-products of heating water.
Water is often called the “universal solvent,” because it dissolves most substances
with which it comes in contact. Water contains dissolved minerals, such as calciumcarbonate (lime), magnesium, silica, iron and phosphate. The amount of these dissolved
minerals in water varies throughout the country and from municipality to municipality.
However, 85% of this country’s area is served with water containing concentrations of
dissolved minerals sufficient to form scale.
When water is heated, it undergoes a chemical reaction that causes the dissolved
minerals to “precipitate” out as solids. The amount of precipitant, or scale, is directly
proportional to the volume of water used and its temperature.
Harmful Effects of Scale
Scaling and corrosion will inevitably cause efficiency losses, malfunctions and
total equipment failure. It is responsible for millions of wasted dollars each year in
maintenance costs and energy consumption.
Scale has a very low thermal conductivity. In fact, it acts as a better insulator than
a conductor for heat transfer. The thermal conductivity of a typical lime/scale deposit
measured in Btu/hr/ft2/in/o F ranges from three to seven. As a comparison, the thermal
conductivity of copper is 2680 and steel is 460. It is easy to see that a heat transfer
surface which has accumulated a scale build-up will have a less efficient heat transfer
process. This means that the metal surface must be hotter for the same amount of heat to
be passed through both the metal surface and scale accumulation then into the water. If
enough scale is present, the metal overheats, causing distortion, embrittlement and
eventual failure of the water heater. In fact, as little as one-fourth of an inch of lime scale
on the heat exchanger can increase operating costs by 25% to 40% and cause tank failure
in as little as two years.
Scale buildup from hard water also causes the following serious problems:
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clogged water pipes
reduced water pressure
“frozen” valves on faucets
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hard to remove soap film on shower tiles and doors
white deposits on shower heads
spots and milky clouding on glassware and silverware
crusted rings in toilet tanks
spotting on tubs, chrome and tile
poor sudsing of soaps, detergents, and shampoos
scale related performance decreases in other appliances that use water
Prisons Energy Expense
A prison is similar to a hotel, or university, with lodging, showers, food
preparation, creating above average energy use. It is estimated that 25% of a prison
energy bill is for heating water. The average prisoner uses 75 to 100 gallons of water per
day, with 40 to 50 gallons of that being hot water for showers, food, laundry and other
needs.
Shower Water and Energy Use Calculation
Water Parameters
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Average Shower Time: Enter the amount of time you normally shower.
Shower Head Water Usage: The number of gallons per minute your shower head
uses. If you cannot find this value, many shower heads made today use 2.5
gallons per minute.
Cost: The cost of water per 1000 gallons used. The national average is $2 per
1000 gallons.
Water Heater Parameters
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Energy Type: The type of energy your water heater uses. The typical water heater
uses either gas or electricity.
Cost: The cost of one unit of the particular energy type your water heater uses.
You can select the state you live in to get the average energy cost for the
particular energy type your water heater uses.
Efficiency: This is measured as an Energy Factor (EF), which is usually listed
beside the Energy Guide label. The higher the number, the more energy efficient
the water heater. On average, an electric heater has an efficiency rating of .92
while a natural gas heater has a rating of .59.
Water Temperature: The temperature of the ground water before being heated.
Shower Temperature: The temperature at which the shower water is raised. A
temperature above 120o F can be dangerous for use.
*Water Use Table
Average Shower Time
Shower Head Water Usage
Water Cost
10 minutes
2.5 gallons/minute
$2/1000 gallons
*Water Heater Usage
Energy Type
State
Cost
Efficiency
Water Temperature
Shower Temperature
Electric
Florida
$0.1155 per kWh
0.927
55oF
Hot / 115oF
*Shower Water Use (gallons)
Day
Water
25
Energy
3.949
Week
175
27.645
Month
750
118.480
Year
9125
1441.508
*Shower Water Cost
Day
Water
$0.05
Energy
$0.46
Total
$0.51
Week
$0.35
$3.19
$3.54
Month
$1.50
$13.68
$15.18
Year
$18.25
$166.49
$184.74
*reference: www.paystolivegreen.com/2009/01 (shower water and energy use calculator)
Based on average treatment costs and average water use costs, we are able to estimate a
savings range. If water treatment costs is $2.00 per 1000 gallons or less, and energy
savings is between 25% and 40%, you will receive a minimum return on investment of
2.29 to 1 at the 25% savings range, but could be as much as 3.65 to 1 at the 40% savings
range. These calculations are for energy savings only. Reduction in maintenance costs
and other efficiencies will further enhance your investment in ScaleSafe Water Treatment
Systems.