Solar Panels and PHEVs

[jayman]

Originally Posted by icarus

Look into a water medium heat pump for your a/c. The waste heat from the a/c is captured into domestic hot water. This has two benefits. The first is "free" hot water, the second is the a/c compressor runs much more efficiently.

A geothermal exchange heatpump system is far more efficient for most on-grid folks, but realistically you'll still need a 240 volt, 30-40 amp breaker. The inrush current to start up a typical 5 ton heat pump is formidable

A desuperheater recovery system for the domestic hot water should be standard equipment on heat pumps. Really, a no-brainer, the savings on heating hot water are very significant during the cooling season

For an off-grid home, perhaps a better solution for cooling would be a natural gas or propane powered adsorption cooling system. Most large chillers for commercial office space, industrial, etc, use the adsorption system. The system is sealed, usually the charge is lithium bromide and water

Ok, just looked into it. they actually do make residential adsorption coolers

Gas Airconditioning and Cooling Equipment Home Page

The electricity demand would be minimal, you're just running a few pumps, not an actual compressor. I would expect such a system to easily cost 2-3 times what a conventional split-system would cost, and would approach the cost of a geothermal exchange heat pump system

But if you're constrained due to off-grid, it would be the way to go and maintain reasonable summer comfort

[icarus]

What a lot of off grid folks are doing is going with the newish mini-spit heat pump systems. The Sanyos for example will draw as little as 300 watts, and they have soft start compressors so that they do not require massive current to start. All in all a pretty good technology.

Icarus

[jayman]

Oh, you mean like the Mitsubishi Mr Slim series? They best ones have Inverter soft-start.

I'm looking into a Mr Slim inverter heat pump for my master bedroom, as I like to sleep in cooler temps but don't want to bring the entire house down that low in summer. According to their specs, on Lo it runs on about 160 watts

Mitsubishi Electric - Product Information for MSZ-A09NA

Yes, with PF correction too

[Zythryn]

Originally Posted by drees

PA Prius - where do you live that the utility is willing to pay you so much for your system and is also willing to pay you for any excess electricity produced?

Most places I know of you are giving the energy away if you don't use it - though I've read that it will hopefully be changing in more places over the next couple years.

I am not sure about 'most places' but in MN the utility companies are paying about the same amount (within 5%) for excess electricity as they charge.
And while I didn't get as good a deal from our utility company, they still helped out with it a little bit

[icarus]

Originally Posted by jayman

Oh, you mean like the Mitsubishi Mr Slim series? They best ones have Inverter soft-start.

I'm looking into a Mr Slim inverter heat pump for my master bedroom, as I like to sleep in cooler temps but don't want to bring the entire house down that low in summer. According to their specs, on Lo it runs on about 160 watts

Mitsubishi Electric - Product Information for MSZ-A09NA

Yes, with PF correction too

I was actually referring to the Sanyo which I am only marginally familiar with. My guess is the "Mr Slim" is similar technology.

Icarus

[fuzzy1]

Fujitsu also has similar units, and some 9-12-15kbtu models qualify for the U.S. incentives this year and next.

[hill]

Originally Posted by radioprius1

This was my next question regarding costs. The solar installers show how you can get a $25,000 system for $5000, but I was curious if you had to lay out the whole $25,000 initially and then wait around for all the credits, etc. That makes these things a whole lot less attractive. It's a whole lot easier to part with 5,000 in cash than 25,000.

Do you (anyone) think that the solar installer companies would ever install it for the after rebate amount and wait for you to get the rebates to pay the rest?

Many established CA companies do this ... but startups don't necessarily have the dough to lay out $$ and wait. I'd bet many other state's installers work the same way. Our installer had to wait at least 4 months, because they were so lax in getting all the "I's" DOTTED & "T's" crossed with the state's requirements ... as though it was no big deal for them to get so close the the state's deadlines that they could loose the incentive they'd sponsered.

Originally Posted by PA Prius

That explains our difference. Our utility company charges a flat rate.

PA P

That's what our MT home is under. Not much incentive for folks to easily conserve 400Kwh-500Kwh of their monthly usage if it costs the same as the 1st 100Kwh used each month.

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