Solar water heat required in new Hawaii homes

[RainDog]

http://www.msnbc.msn.com/id/24468002/

[glenn kangiser]

Maybe a good idea but the $5000 price is kind of exorbitant I think. 

I wonder if you could build your own or... if you are limited to some commercial profit maker for the legislators and their accomplices?

[pagan]

They pass a law mandating solar hot water heaters while at the same time ending the tax credits for installing them. Most likely these systems will need to be designed and installed by a "professional" preapproved by the state.

[Squirl]

$5000 Seems high.  My understanding is it never gets below freezing down there so I don't see why a simple drain back system wouldn't work.  Most of the cost is probably the controlled market for labor (approved installer.)  On the other hand, I believe the cost of energy is really expensive in Hawaii and subsidized heavily.

[John Raabe]

My 2 tank batch water heater system cost about $750 when I installed it in a sunroom in 1984. I have spent maybe another $400 on repairs (replaced a tank).



There are two large skylights (you can see one in upper left) each with a black tank in series to the electric hot water heater.
www.countryplans.com/Downloads/solar_wood_water.PDF

A batch system should work well in HI where there is no chance of freezing. You could leave them outside with minimal insulation. I have mine in a passive solar sunroom that has never gotten close to freezing.

Some installers do not like batch systems but they are the most simple of all.

Here's a kit: http://www.solar-components.com/batchheat.htm
Here's a PDF set of plans: www.builditsolar.com/.../WaterHeating/FSECFS36Batch11349.pdf

[RainDog]

 Very, very good. Thanks for the links, John!

I hope to incorporate a solar water heater into my build when this damn white elephant I'm in now finally sells.

PS: That .pdf didn't link for me. I think this is what you were referring to, though:

http://www.builditsolar.com/Projects/WaterHeating/FSECFS36Batch11349.pdf

[glenn kangiser]

Does it provide all of your water heat and do you have backup, John?  Estimated percent of water supplied or savings?

Thanks

[MushCreek]

This is the kind of stuff that really bugs me about regulation, especially if they don't allow DIY (I don't know if they do or don't). It ties in with the Katrina thread currently running. They pass laws favoring an industry, and the little guy who can't afford it is just screwed. It's like the mandatory sprinkler systems starting to crop up. From what I've heard, once they are required, you will have to have it installed by a certified installer, which means $$$. As they tighten up building codes, I can see more and more people being priced out of the market, all the worse with the economy we are currently in. I hope I can get my little place built in SC before all this bureaucratic stuff hits the fan!

[RainDog]

Considering most people aren't going to get out there with hammer, nails, and reclaimed materials to build one themselves, the $5000 cost seems to be about what I'd expect.

Commercial systems seem to run from around $1500 to $9000, and that's without installation.

For someone on a tight budget, such as I, an added 5000 bucks could be a real game-changer.

http://www.google.com/products?q=solar+water+heater&oe=utf-8&hl=en&show=dd&sa=N&lnk=next&start=10

[pagan]

It's similar to the federal government mandating things for the states and leaving it up to the states to figure out how to pay for the government mandate. Now we see states and municipalities mandating sprinkler systems and solar hot water heaters and leaving it up to the home owners to come up with the money. Here's the thing, even if you have a fancy state of the art sprinkler system you'll still be required to pay property taxes to fund a fire department even though your house will put itself out long before the fire department arrives.

[Dave Sparks]

Agree with John about the batch heater but there is also the other direction if asthetics or codes drive issues. If I were in the tropics and I wanted super efficient water heating I would go with a condensing gas heater open loop to the collector. The condensing heaters are 95% effiecient (use 1/2 inch gas lines and recover nearly as fast as tankless)and with open loop solar the heater/tank will not have any appreciable standby loss. Open loop also has the least loss due to the lack of a heat exchanger so there will be fewer collectors on the roof or array.

[John Raabe]

Interesting design Dave. Do you know of any diagrams that help explain the open loop solar/gas system?

My batch system supplies about 40-50% of hot water needs on a yearly basis. It is a preheater to a conventional tank.

[Dave Sparks]

Interesting design Dave. Do you know of any diagrams that help explain the open loop solar/gas system?

My batch system supplies about 40-50% of hot water needs on a yearly basis. It is a preheater to a conventional tank.

Homepower mag has all the nice graphics but it is so simple I can even describe it...
This is in it's most basic form and it can evolve in complexity and capacity.
Start with a 50 gallon (but 40 will work) gas heater. The condensing gas heater is best but any gas heater will work. You must live in places that do not hard freeze or drain the solar loop during weather below 30F.

The hot water outlet gets a tee installed as does the cold inlet. An "el cid" or similar 5 watt pump run by solar circulates the water in the tank from the cold inlet to the collector and back to the hot inlet.  Open Loop!

The collectors can easily be made but there are commercial ones. A safety pressure relief valve and a few tweaks and voila!

Down here in the mountainland of fruits and nuts it can run 10 months a year if the collectors are sized right.  The batch heater is great also and if I were to start fresh in your neck of the woods I would only consider a drainback with "lot's" of collectors.

Check out the condensing gas tank heaters from AO Smith "Vortex". Pretty amazing technology that really hurts the case for tankless design.

PS  I really look forward to when I have time to go thru this forum! It is a highlight for me! Simply the best!

[pagan]

I built a solar batch heater last summer but in central Vermont we just don't get enough solar gain to make it viable. Most days the water was cool to mildly warm, and on only three occasions was the water even remotely what I'd call hot. I've been looking into a combination tank so I could have solar hot water coming in from panels and also a second loop to run through my Waterford Stanley cook stove. My major issue is the fact that I'm planning on building a new house within the next three to five years, so should I put the effort into the dual system now and then have to move it all in a few years, hopefully, or should I just go with a simple LP gas on demand?

[RainDog]

FYI and mine:

http://www.homepower.com/basics/hotwater/

Thanks for the reference, Dave.

[John Raabe]

Good information Dave and Raindog.

I think I need to build one more house to do all the things I didn't or couldn't do in the one I have now.

[Dave Sparks]

Good information Dave and Raindog.

I think I need to build one more house to do all the things I didn't or couldn't do in the one I have now.

Your in better shape than I am John, one more would bury me!  I even have the song picked out to play that day.

The homepower info is wrong about the tank loss data in regard to my point about condensing tank heaters. They are too new and only now really available. Good reference!