Alternative Power sources - Energy Smart Water Heater and Timer Use.

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Energy Smart Water Heater and Timer Use.

Clearfield Consumer

2006-11-29, 3:25 am

Forgive me if this is the wrong group but I know there are some smart
people here regarding energy use.

I recently moved into a home that has a new Whirlpool Energy Smart
water heater that uses the little computer control box and is claimed
to save electricty.

http://www.whirlpoolwaterheaters.co...lectric_how.php

This water heater is also hooked up to a timer. The previous owner had
the control set to "Smart" in which case the water heater operates like

a conventional unit and also had it on a timer.

I am under the impression that a timer on a water heater this new is of

little use and that it will also interfear (sp?) with the operation of
the Energy Smart circuit. I am thinking that setting the control to
"Energy Smart " mode and not using the timer would be a more
economical choice.

Should I disconnect the timer and let the energy smart circuit do it's
job or can they both be used together?

Astro

2006-11-29, 9:25 am

On Nov 28, 10:57 pm, "Clearfield Consumer"
<ClearfieldConsu...@gmail.com> wrote:
> Forgive me if this is the wrong group but I know there are some smart
> people here regarding energy use.
>
> I recently moved into a home that has a new Whirlpool Energy Smart
> water heater that uses the little computer control box and is claimed
> to save electricty.
>
> http://www.whirlpoolwaterheaters.co...lectric_how.php
>
> This water heater is also hooked up to a timer. The previous owner had
> the control set to "Smart" in which case the water heater operates like
>
> a conventional unit and also had it on a timer.
>
> I am under the impression that a timer on a water heater this new is of
>
> little use and that it will also interfear (sp?) with the operation of
> the Energy Smart circuit. I am thinking that setting the control to
> "Energy Smart " mode and not using the timer would be a more
> economical choice.
>
> Should I disconnect the timer and let the energy smart circuit do it's
> job or can they both be used together?

I just installed one of these and have been doing energy measurements
on it. When idling, the unit uses less than .05kwh/day, so turning it
off at night is of minimal use. Further, while the technical details
are lacking, they describe an adaptive control system that allows the
water to cool during idle periods and ramp up during learned high use
periods. They don't indicate whether the internal clock is battery
backed, but I doubt it. If that's the case, then every time you power
the unit down then back up, it's likely to reset itself to it's
original condition and lose all its smarts.

If it were in my house, I'd remove the timer to avoid the temptation
for someone to use it. The water heater already has an energy factor of
0.95, the best in the business as far as I can tell, so turn it on and
let it do its stuff.

nicksanspam@ece.villanova.edu

2006-11-29, 9:25 am

Astro <tedinoue@gmail.com> wrote:
><ClearfieldConsu...@gmail.com> wrote:

http://www.whirlpoolwaterheaters.co...lectric_how.php
[color=darkred]

Given good heater insulation, it might use more energy than it saves.
[color=darkred]

I'd disconnect it.
[color=darkred]
>I just installed one of these and have been doing energy measurements
>on it. When idling, the unit uses less than .05kwh/day...

That's only 2.1 watts, vs 4 for an alarm clock motor. How much power does
the timer use? That's a very small heat loss. If a 115 F 50 gallon heater
with 25 ft^2 of surface in a 70 F room only used 0.05 kWh/day, ie 7.1 Btu/h,
the US R-value of the surface would be (115-70)25/7.1 = 158, like 46 inches
of fiberglass, at R19/5.5". Something seems wrong here. Maybe your meter is
less accurate at low power levels.

>... they describe an adaptive control system that allows the water to cool
>during idle periods and ramp up during learned high use periods.

Lower the setpoint by 0.3 F (minimum 115 F) whenever the lower element
turns on and raise it by 3 F whenever the upper element turns on, up to
a max user setpoint. We could save more energy with a lower min temp or
a much cleverer scheme that leaves the heater filled with cold water
overnight or a "vacation detector."

>They don't indicate whether the internal clock is battery backed...

I doubt there's an internal clock.

>If it were in my house, I'd remove the timer to avoid the temptation
>for someone to use it. The water heater already has an energy factor of
>0.95, the best in the business as far as I can tell, so turn it on and
>let it do its stuff.

An Oregon web site defines the DOE energy factor as "the ratio of useful
hot water output to energy used by the heater, over a year's time." If
an electric heater with an energy factor of 0.95 loses 0.05 kWh/day, it
would supply 0.05/(1-0.95) = 1 kWh or 3412 Btu/day of hot water, enough
to heat G gallons per day from 60 to 120 F, where 8.33G(120-60) = 3412,
so G = 68, which seems reasonable.

Nick

Clearfield Consumer

2006-11-29, 5:25 pm

Thanks for the advice, I disconnected it this morning.

nicksanspam@ece.villanova.edu

2006-11-30, 9:25 am

Astro <tedinoue@gmail.com> wrote:

http://www.whirlpoolwaterheaters.co...lectric_how.php

>
>That's only 2.1 watts, vs 4 for an alarm clock motor. How much power does
>the timer use? That's a very small heat loss. If a 115 F 50 gallon heater
>with 25 ft^2 of surface in a 70 F room only used 0.05 kWh/day, ie 7.1 Btu/h,
>the US R-value of the surface would be (115-70)25/7.1 = 158, like 46 inches
>of fiberglass, at R19/5.5". Something seems wrong here. Maybe your meter is
>less accurate at low power levels...

[color=darkred]
>If an electric heater with an energy factor of 0.95 loses 0.05 kWh/day, it
>would supply 0.05/(1-0.95) = 1 kWh or 3412 Btu/day of hot water, enough
>to heat G gallons per day from 60 to 120 F, where 8.33G(120-60) = 3412,
>so G = 68, which seems reasonable.

Oops. If Ein = Eout/0.95 and Ein-Eout = 0.05 kWh, Eout = 0.95 kWh, ie
3241 Btu/day = 8.33G(135-58), which makes G = 5.05 gallons per day.
G = 64 gallons per day (Eout = 41,050 Btu/day) would make Ein-Eout
= 2161 Btu/day, ie 0.63 kWh/day.

DOE says:

> The Energy Factor (EF) is the measure of the overall efficiency for a
> variety of appliances. For water heaters, the EF is based on three
> factors: 1) the recovery efficiency-how efficiently the heat from
> the energy source is transferred to the water; 2) standby losses-
> the percentage of heat lost per hour from the stored water compared to
> the heat content of the water; and 3) cycling losses.

For an electric storage water heater, this may boil down to standby losses.

> The EF is determined under specific test conditions; for reference see:

http://www.eere.energy.gov/building...ers_051198.html

> Here are the current minimum energy efficiency standards for water heaters
> manufactured on and after 01/20/2004:

> Product Class.....Energy Factor

> 1. Gas fired.....0.67 - (0.0019 X rated storage volume*)
> 2. Oil fired.....0.59 - (0.0019 X rated storage volume*)
> 3. Electric.....0.97 - (0.00132 X rated storage volume*)
> 4. Tabletop.....0.93 - (0.00132 X rated storage volume*)
> 5. Instantaneous Gas-fired.....0.62 - (0.0019 X rated storage volume*)
> 6. Instantaneous Electric.....0.93 - (0.00132 X rated storage volume*)
>
> * Rated storage volume = the water storage capacity of a water heater,
> in gallons, as specified by the manufacturer

Nick

barry@sme-online.com

2006-11-30, 1:25 pm

Clearfield Consumer wrote:
> Forgive me if this is the wrong group but I know there are some smart
> people here regarding energy use.
>
> I recently moved into a home that has a new Whirlpool Energy Smart
> water heater that uses the little computer control box and is claimed
> to save electricty.
>
> http://www.whirlpoolwaterheaters.co...lectric_how.php
>
>
> This water heater is also hooked up to a timer. The previous owner had
> the control set to "Smart" in which case the water heater operates like
>
> a conventional unit and also had it on a timer.
>
>
> I am under the impression that a timer on a water heater this new is of
>
> little use and that it will also interfear (sp?) with the operation of
> the Energy Smart circuit. I am thinking that setting the control to
> "Energy Smart " mode and not using the timer would be a more
> economical choice.
>
>
> Should I disconnect the timer and let the energy smart circuit do it's
> job or can they both be used together?

Some of this may be between you and your utility. Don't/won't have an
electric water-heater, but my parents' one had a timer on it, to get a
lower rate from utility, because the timer disabled the lower heating
element except during off-peak hours.

Except you were agreeing to suck up fewer kwh during waking hours, and
automating this with a timer, for $ incentive, you'd have to be public-
spirited to bother with any of this. The "smart" part has to do with
limiting utility peak load. And new generator construction, etc.

J

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