Solar DHW

You are in New Jersey so it might be worth check this link out to see if there are any incentives for DHW.

http://www.dsireusa.org/incentives/index.cfm?re=1&ee=1&spv=0&st=0&srp=1&state=NJ. Otherwise its a 30% tax credit for the installed cost. As long as its a SRCC rated system, the fed doesnt require a licensed installer but you local building code may.

Here is a package price for DIY systems that are SRCC rated. A rough rule of thumb is one panel per person. Builditsolar.com has home made designs but they wont qualify for the fed rebate.

http://www.altestore.com/store/Kits...4-People/Closed-Loop-AC-Powered-w-Tank/c1124/

Typical payback is usually 5 to 7 years.

I have a wood boiler that uses my oil controls and pumps to heat the house. One zone is to a hot water maker tank, which is bascially an insulated tank with a coil in it. During the winter, I use the SHW as a preheater upstream of the hot water maker, in the later spring through fall, I run the SHW direct as my hot water and bypass the hot water maker. The SHW tank is equipped with an electric backup coil but I have never hooked it up. If I run direct, I can leave the boiler and controls powered down all summer, it saved me a about a gallon of oil per day. I actually have a solar powered circulator pump so there is no electric load for hot water except for my water pump for 5 months per year

Do note there are two types of systems, evacuated tubes and flat plates, evac tubes put out hotter water but less of it while flat plates but out more water but at lower temp. If you want to integrate the SHW with storage, evac tubes would work better as flat plates only raise the water temp over the outside temp by about 80 F max while evacs are more like 180 degrees. Evacs cost a lot more and you need to have a fool proof way to dump the heat in the summer.

The panels are roughly 4x 8 and should be mounted at your latitude plus 15 degrees (I.E I am at 45 degrees lat so my panels are tilted at 60 degrees. Unfortunately that rarly lines up with the roof pitch so they can be ugly. If you drop them to typical roof pitch they wont work as well in the winter, plus will tend to build up snow and will overheat in summer.

Rigging them in place is a two person job preferably with a crane. I built a derick out of 2x4's and used pulleys and come alongs. Whatever you do make sure you have someone who knows roofing to install roof boots for pentrations and flash all the points that the panels are attached to the roof. The piping is pretty straighforward, the biggest hassle is finding a charge pump to charge up the system (I bought one from Northern Freight).

Depending on how well your tank is insulated, you can install a rather petite solar system that would basically be sized for DHW and have it work with your 500g tank. This is very dependent on having a well insulated tank.

To interface with a pressure tank, a plate hx is probably the simplest way to do this.

Check out www.builditsolar.com for DIY flat plate designs. IMHO, flat plates are the way to go. If you can build your own, you are way ahead of the game.

Solar output at optimal angle put out aprox 100 BTU/sq ft/hr. So if you are looking to heat enough water for 2 or 4 people? roughly 40k BTU per day for water heating. Roughly 7 hours of heating day, thats roughly 60 sq ft of collectors, factor in some cloudy days, you are looking at 3 - 4 X 8ft panels. Manufactured systems have alot of govt incentives that help pay for them but they are expensive. To build a stand alone solar system to produce the heat abouve you are looking at $4-7K professionally installed. Look at http://www.dsireusa.org I think in NJ its called the WARMadvantage program are the state incentives you can use, and there is a flat 30% federal incentive for renewable resources that you can use on your income taxes. With the combination of those 2 you could pay for 50% of the system.

To build something DIY you can look at http://www.builditsolar.com/ they have tons of plans to but DIY collectors. If you get creative you can do some type of heat exhanger that connects to your hot water, then dumps any excess into your pressurized storage and help out with the shoulder season. I am looking to build next year after my PAXO is up and running a 100-120sqft collector on my garage roof that I will plumb undergorund into my house and connect with my hot water tank and EDPM unpressurized tank. For the collector since I am going to build it as part of the roof, the cost factors are alot less, and it saves me $ on shingles too. I figure I can build it for about $900-1000 because the tank and DHW are already in place.

Personally I think cheap DIY systems are perfect completment for wood boiler systems, because solars best output is when you dont want to be burning wood.

Take a look through nofossil's website http://www.nofossil.org it will give you some more insite to what possbilities there are.

man I spent too much responding, peakbagger beat me to it!! I would stick with flat plate exchangers or DIY collectors, the evac tubes are expensive, and you are not looking to use there advantage of a higher delta T in the winter, its called tossing a log in the boiler. As far as pitch of the panels you want to put them at the best output for the summer, because you dont care if they work in the winter. Latitude +15 is a good rule if it was a stand alone system trying to heat in the winter, but you have a boiler for that.

You have to look into what incentives apply in NJ on the DSIRE website, then get 30% back in your taxes at the end of the year. I got 3 different incentives for my PV solar system last year. ended up paying for 71% of it. They are out there you just need to research them. Sometimes the stipulation is they need to be SRCC rated and installed by a licensed contractor.

Here is some good info.

http://www.nyserda.org/programs/Research_Development/gibbs-final.pdf

Peakbagger has it right, but...

The DIY approach can be combined with factory panels for the federal credit, I think the panels have to be certified to qualify for the credit and the rest can be DIY, check builditsolar, that's where I read about that approach.

Some people on here only use their solar in the spring (the solar mirror image of summer), summer, and early fall, and drain them for the winter. The solar panels will contribute next to nothing for heat in the winter, and you can angle them at latitude for maximum solar gain in the months that you will be using them.

Depending on how involved you want to get, tempering cold water is a great way to extend your warm season solar hot water, there's no reason to use your limited solar btu's heating water from 55-70 when the air temp is higher than that.

Benjamin's approach from Build it solar makes sense as the SRCC ratings are for the panels not the balnce of system. The biggest ticket item for the rest of the system is the storage tank/heat exchanger combination.

There have been comments by Tom in Maine in other threads about the use of EPDM liners for tank linings shown in build it solar but I hadnt noticed that chuck had 500 gallons of storage. therefore, the major cost is the panels and controls and circ pumps. With some creativity, he may be able to use an existing circ pump. The federal program doesnt have any requirements on who installs therefore the federal rebate is in effect. I expect he would have to research the NJ program to see what the requirements are for state rebates. Odds are he may have to hire a plumber and possibly have a site survey which adds to the costs significantly.Since it is a summer only system, one flat panel aligned at latitude -15 degrees may be enough, but to cover some of the shoulder seasons, its probably worth a second panel. I would consider saying the heck with glycol and just draining them when the nighttime temps drop below freezing as by then he would be running wood.

Link for retailer

http://www.altestore.com/store/Solar-Water-Heaters/Solar-Collectors-and-Mounts/c1185/

Take your choice, I have the AET's. Whatever you do make sure you buy the appropriate mount kit. My original link is for kits but you dont need a tank so the kits dont make sense.

The more I read and learn the more I would like to install solar water heat for the summer. Maybe in a few years when I get all my other projects finished up.

also most of the new solar controllers have the ability to run the solar and 2 or 3 of your heating functions. They have multiple delta t functions, data logging, etc built in. You should be able to pull 20% of your dhw load in the winter months and 100% in summer with a reasonable sized array.

hr

chuck172 said:

Can I get a link to a retailer who sells these panels? With prices?
My house (bi-level) is facing the south east. I currently use a 40 gallon superstor indirect water heater (in basement) with the insulated 500 gallon pressurized storage and oil back-up.
Would the installation simply be mounting the panels, bringing the supply and return lines down to the basement, piping to the superstor or storage with of course the circ. pump and necessary controls?

Click to expand...

Thats the general jist of it. Once the panels are mounted on the roof, then get the supply, and return lines connected and into the basement, the rest is pretty much right there in the basement. If you are going to use the system year round it will have to have antifrezze in it, so a heat exchanger would be in order. The other option is a dual coil water heater.

chuck172 said:

Can I get a link to a retailer who sells these panels? With prices?
My house (bi-level) is facing the south east. I currently use a 40 gallon superstor indirect water heater (in basement) with the insulated 500 gallon pressurized storage and oil back-up.
Would the installation simply be mounting the panels, bringing the supply and return lines down to the basement, piping to the superstor or storage with of course the circ. pump and necessary controls?

Click to expand...

Check out Wagner-Solar Inc.
484 Maaschusetts Ave.
Cambridge MA 02139
1-877-97Wagner
www.wager-solar.com

It's considered the pioneer in Germany and they are now on the US market since about a year.
There Flat-plate collectors seems to have the best SRCC rating
They also have tanks

Contact person is Tyler Plante

It's hard to beat free wood and free labor.

I still really like the $1,000 (+) solar system on builditsolar, especially for heat and hot water in the warmer months and especially in combination with wood heat and hot water for the cold months. It's a matter of convenience of course, and if you have a great wood setup then that might be your most convenient solution.

My situation suits a DIY solar system since I dont want to be running my boiler in the middle of the summer in my basement and heating the house. If I had a woodlot right next to my house, and my boiler in an outbuilding, it might not be worth the money, but it might be worth the hassle of feeding the fire for a few months.

Gary built the system, he's on here occasionally. I cobbled together almost 300sf of old flat plate collectors and other pieces that cost well under $1,000, IF you only count the supplies that went into the system and don't count any labor (I always pay FULL price for labor!).

I also have a cobbled together boiler that I use once or twice a week Dec-Feb, and that's enough, there's no way I would want to burn through the summer for hot water with MY setup.

If you usually leave your windows open the extra heat isn't going to be a big deal. If you run AC much that's another source of free heat that could be used for DHW, as in a desuperheater on a heat pump.

As one who manufactured flat plates for many years, Gary's builditsolar.com plans are really good and can certainly be a best deal if you
want to build your own. You can certainly go over $1000 but figure that the collectors cost $5-7 per square foot along with a controller ($60-175) and
a circulator (if a drainback, probably something like a bronze Taco 009~$285). The rest is small stuff and plumbing.

If you already have a storage system, the system can either be a simple drainback if the tank is unpressurized or an antifreeze if it is pressurized.
Either way, drainback or antifreeze can be done on either tank since the additional hardware is not too expensive.

Since we are talking about a non-heating season system, the collectors should be relatively shallow pitch, like flat mounted on a roof.
This will optimize the performance for the best time of the year--spring, summer and fall, when the solar input is relatively high.

[quote author="chuck172" date="1304290663"]I insulated the piping and storage tank. The boiler itself doesn't give off much heat. The extra heat in the basement is noticable on real warm days but doesn't really seem to amount to much.

Though I've got to ask, has anyone here actually built the $1000.00 solar heat system?[/quote]

Absolutely, I just posted this in the green room describing my DIY system:

https://www.hearth.com/econtent/index.php/forums/viewthread/74746/

There are several more examples here:
http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm#Example1KSystems

Built one of Gary's here in northern Maine. 4 by 8 to a 550 gallon unpressurized tank, a drainback system. Turned it off for the winter, going full bore now. This was a test project and it worked great, I plan to triple the size of the collector. The biggest expense was a pump with enough horsepower to lift the water...don't undersize the pump. I also ordered the fins from one of Gary's buddies who has a tin knocking shop, cheap, fit perfectly and a joy to talk to.

I didn't fuss with the perfect angle, just attached to the south side of the house. Trying to be perfect in solar is like searching for the holy grail. Just my opinion.

Steve