Quote:
Originally Posted by Servicetech
Electric Thermal Storage vs. Heat Pump Water Heaters - Home Energy Pros
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Not quite sure what your point is here...
Curious that the article differentiates between
- Units that heat up water during off-peak times so that it can be called upon during times when electricity costs less.
- Units that use heat pumps to heat water with greater efficiency.
They say this as if heat-pump water heaters could not be used during off-peak times... odd.
The article also mentions a project wherein electric [resistance] water heaters will be designed to be as efficient as current heat pump water heaters. Since the resistance heating process already is essentially 100% efficient, there will be no gains to be made there... So it looks like superior insulation will make the difference.
So, if you converted a super-insulated electric water heater to be a heat-pump water heater, and managed it (can you spell Arduino) to run at off-peak times, you'd be a triple winner.
In fact, I believe that Xringer is doing something pretty much like that (maybe minus the super insulation), but he is adding solar energy to the mix. Last I tuned in, he was using his solar panels to power a resistance element, so it could be improved by powering his heat pump with solar volts kicked up to 120AC via an inverter.
Efficiencies do add arithmetically.
BTW, there is a
Fuel Comparison Calculator available that will allow you to input fuel values (even Oklahoma Nat Gas) and specific efficiencies, too... so you can double check that your posts are correct before you push the "Submit Reply" button.
And also since this is a get-down-and-dirty DIY Energy Geek forum, making claims about Break-Even becomes a little bit more difficult, since many of our most resourceful members glory in being able to convert discarded (as in trash) HVAC units into fully functioning units that they were never originally designed to be.
HERE is a perfect example of what I am talking about. His neighbor asked him to haul some stuff to the dump since he was going there anyway... And he made a functioning heat pump water heater from that trash. That homemade unit is now saving his parents hundreds of dollars per year.
But you could actually use the Fuel Comparison Calculator to figure Break-Even, for cases that unusual.
Best Regards,
-AC