Solar water heater

[mgconnor13 206]

I'm thinking about building a solar water heater to help lower my electric bill. Has any one used a solar water heater? I live in southern NC (zip code 28376) and it gets below freezing at night in the winter.

 

What type of system would be the best? I'm trying to make this a DIY project. I've been looking at a batch heater design but I think it might get too cold for that during the winter.

 

My other ideas is to build a flat panel and the using 55 gallon drum(s) as holder tank(s) above it so I can use convection to circulate the fluid. Then running the cold water line that feeds my hot water tank through it to pre-heat the water on it's way to the hot water tank. Since it does get below freezing here I'm thinking if I insulate the crap out of my lines and holder tank(s) and use radiator fluid I can avoid freezing. For a heat exchange in the holding tank I'm thinking about a coiled copper pipe or using some type of radiator.

 

Any ideas or help would be great. Thanks

[jnelson228 4]

I'm thinking about building a solar water heater to help lower my electric bill. Has any one used a solar water heater? I live in southern NC (zip code 28376) and it gets below freezing at night in the winter.

 

What type of system would be the best? I'm trying to make this a DIY project. I've been looking at a batch heater design but I think it might get too cold for that during the winter.

 

My other ideas is to build a flat panel and the using 55 gallon drum(s) as holder tank(s) above it so I can use convection to circulate the fluid. Then running the cold water line that feeds my hot water tank through it to pre-heat the water on it's way to the hot water tank. Since it does get below freezing here I'm thinking if I insulate the crap out of my lines and holder tank(s) and use radiator fluid I can avoid freezing. For a heat exchange in the holding tank I'm thinking about a coiled copper pipe or using some type of radiator.

 

Any ideas or help would be great. Thanks

 

You should be able to work around the issues with the outside temp, but,what you will need is heavy sunlight year round. If you are getting Full sun through the better part of most days this project might be worth the effort if not then I would look at something else. Also hot water alone is not going to save you that much money if you already have an efficient water heater.

 

If your just looking for a new hobby because you ran out of gun projects or the woman said, damn it, not another gun you need to find something more constructive to do with you time! Then I wish you luck on your new hobby.

 

There's my

 

And no I wouldn't be able to relate to that at all.

Edited November 4, 2010 by jnelson228

[mgconnor13 206]

I'm pretty sure my water tank is as old as the house. Unfortunately electricity is one of the most expensive ways to heat ad you lose heat every minute the water is sitting in the tank. In the summer it's 100+ during that day, that alone is better then pulling cold water straight out of the ground. I doubt I'll get year long heat but it's better then paying the electric bill. If I save 10% over 15+ years I figure it's worth it.

 

Besides solar water heaters are big in other countries. Israel requires them on new homes and Israel figures it saves them about 2 million barrels of oil a year in heating fuel nation wide.

[SirROFL 13]

It might be easier to simply buy a small PV solar panel to power an electric water heater separate from your tank. That way if the sun isn't out or the closed-circuit solar unit can't handle the load the regular heater will kick on as it usually would.

 

This way requires less work and fewer trips to the plumbing store.

[gtnichols 51]

well it's no doubt the biggest savings, that are easiest and cheapest to get are from solar water heaters.

 

There are "freeze" valves that dump the water in the solar heating system to avoid freeze damage.

 

putting copper pipes on a black roof, under glass is a typical set-up, the pipes circulate to a collector which stores the water for use.

 

there are units that have a central collector that also serves as "the heating cauldron" like a metal 55 gallon drum with mirrors reflecting sun on it, but in places with less sun, and cooler weather these don't perform well.

 

when they work, you get smokin hot water!, when they don't,, could be a wasted effort.

 

do your research first.

[Graniteer 10]

There's a lot of ways you can go wih this. I've been looking into this kind of stuff myself for when I build. I want it energy efficient because I am a cheapskate.

 

Check out tankless water heaters. It's on-demand hot water using natural gas or propane. Wicked efficient and use a small amount of space. I think most can even be mounted on a wall.

 

If you really want to get into a solar water heater, look into Fresnel lenses. They are wicked cheap super-sized magnifying glasses. I saw one in action where I work, and it was able to boil about 250 mL of water within 2 minutes, and it was about 10 out (early December in NH can get kinda cool). The downside is making sure you don't burn your house down or fry something. Lots of stuff on the youtube about this. There's a lot of work involved and a fair amount of engineering.

 

Good luck, and if you do this I'd like to see some pics if possible.

[BpS12 512]

We use to use a coiled black hose on the carport roof to heat water for a "cattle tank" swimming pool for the kids(mostly,lol).

 

Rusty, A preheating system is likely the way to go so that your working with what you have and just adding to it.

 

Do you have a woodstove by chance or even a fireplace? If you do, you can go solar preheat during the warmer months and fire heated during the colder months. The thought is to go with one coil on the roof and one around the woodstove vent pipe or fireplace andirons.

 

I've seen one outfit where a guy used a single pane skylight and then coiled copper tubing around inside of the shaft(ceiling to roof opening) and painted the tubing black. Since the house heat rises, it kept the system from freezing as well as adding to the preheating.

 

Switch valves and drainages are a necessity regardless of your system. You can start with manual valves and go automatic/thermostatic as you can afford it, if desired.

 

Graniteer is right about the tankless systems, their great and we use them for our two weeks at the Penssic War. You can use two 100#(?) tanks and switch the empty out with little to no interuption of service. We do this for our supplemental propane heater. Which is real nice when the power goes out.

 

If you convert to propane, you can gradually switch out your fridge/freezer and even go for a generator to power everything else.

 

Check out ...

http://www.lehmans.com/?partner_id=bcbgoog&utm_source=MSN&utm_medium=cpc&utm_campaign=Brand

[mgconnor13 206]

My plan is to have the solar heater pre-heat the water on the way to the hot water tank with a way to by pass it in the winter.

 

I don't have a wood stove but that is on the to do list. I've thought about welding a box to it and running a couple water lines to it to heat the water. When my water tank goes I want to replace that with a tankless unit.

 

I've been looking at a batch heater but think a thermosiphon system could be a lot better if I build it with a large enough storage tank and insulate it real well. In the summer I'll probably need a tempering valve in case the water gets too hot.

[Graniteer 10]

Whatever you do, make sure you have relief and blowout valves. Especially if you link this to a woodstove. Basically what you're making is a highly pressurized, very hot device with the ability to rapidly expand. I can think of a few items that possess these qualities.

 

Lots of redundancy in your system. I saw a picture of someone who used a woodstove water heating loop, and the valves failed when they started the first fire of the year. Truly scary.

 

Below is a link for Fresnel lense projects, I think you'd really like something like that.

 

[uzitiger 193]

I'm pretty sure my water tank is as old as the house. Unfortunately electricity is one of the most expensive ways to heat ad you lose heat every minute the water is sitting in the tank. In the summer it's 100+ during that day, that alone is better then pulling cold water straight out of the ground. I doubt I'll get year long heat but it's better then paying the electric bill. If I save 10% over 15+ years I figure it's worth it.

 

Besides solar water heaters are big in other countries. Israel requires them on new homes and Israel figures it saves them about 2 million barrels of oil a year in heating fuel nation wide.

 

In Israel the solar heater provided hot water because no other sources of heat were available. Israel has a climate similar to Los Angeles where you don't get freezing weather as here in Ohio which would destroy the system. Israel's water is very hard and the pipes have to be replaced every seven to ten years because of the mineral build up. If the climate in your area is suitable then you should be able to utilize the solar heat and the 100+ temperatures in summer will be sufficient. The last time I was in Israel in winter the sky was cloudy and the solar heaters did not provide heated water for about three days and I had to wash in warm water. The temperature was around 37 degrees and the high humidity is bone chilling in the brick homes. Most homes don't have heat or they have heat pump air conditioners which they don't use on heat cycle because of old habits. Many people use electric grid heaters which are a fire hazard and considerable more electricity than the heat pump air conditioners. Lately the oil filled electric heaters are being used instead of the grid heaters.

[mgconnor13 206]

I've got plans for relief valves and such along with drain valve in the plans I'm working on. My goal is to try to heat the water as much as possible before it gets to the tanks so I can minimize the load on the hot water tank. I realize that some days will be better then others but every little bit helps. The wood heated loop will be farther down the road and require a lot more planning.

[DogMan 2,343]

I hate to throw cold water (pun intended) on your idea, but these things usually turn out to be a major pain in the ass and you may come to realize that all the effort you put in to building and maintaining the system would be better utilized by making a little extra money in other ways to help offset or completely pay for your utility bills. That said, good luck.

[SOPMOD 254]

I have used the evacuated tube solar hot water heater and it makes shower worthy water even when it's cold outside because it is so well insulated.

 

 

the box for your heating tubes needs to be totally insulated, your pipes need to be totally insulated, if you use a tank it needs to be either indoors or wrapped in 4 inch thick insulation.

 

they will make boiling hot water in the warmer months(180F) if they are setup right so be careful not to let anyone get burned. Also you can run them in a circuit with your regular hot water heater as a collection tank and it will keep it from kicking on for days at a time even in cold weather.