Build a Solar Water Heater: An Intregal Passive Solar Water Heater

A do it yourself solar water heater is very difficult to do right. Professionally manufactured and installed systems can be pricey, but in the long run, they’re less expensive than electric or gas water heaters. And you have the peace of mind of a long warranty.

http://www.sunbelt-solar.com

A solar water heater is a great investment. The Return on investment is very favorable compared to solar electric PV panels. www.sunbelt-solar.com

A solar water heater is a great investment. The Return on investment is very favorable compared to solar electric PV panels. www.sunbelt-solar.com

oops. the rest of troy's comment got cut off. sorry for taking up so much of the post here.

TROY:
Here’s what I was thinking relating to shut-off valves. If you have pressure coming from the north side of the house (electric water heater) and pressure from the south (solar) into the bathroom fixtures, you’ll have conflicting pressure, which may change as the temperature of the water changes. Also, if you’d turn on the hot water in a room on the north side of the house, you may be getting water all the way from the solar collector depending on pressure.

ME:
pressure! i didn't think of that. i guess i'm thinking schematics, not dynamic system. so, troy, you seem to suggest that one factor in the pressure is water temperature. is that correct?

i would presume that the solar water, being both hotter (since i would turn the electric one way down) and located above the showers, would be the one getting tapped. for the solar to be providing water to the north side would mean the hot water was going backwards through the pipes. as long as that isn't inherently bad, that's fine with me.

dear readers, what are your thoughts or suggestions?

here's a conversation between troy and myself, following my question about direct connection instead of routing solar heated water to the existing electric heater.

TROY:
Thanks for your comment. Yes, it should be possible, but you’ll probably want to install shut-off valves so that you won’t have backflow concerns. But when you have the valves shut, you won’t have hot water from your electric water heater if you run out of solar heated water. So there are a lot of variables, including the climate where you live.

ME:
thanks for your fast and informative response.

by "backflow" do you mean the house water going back into the collector rather than just out of it? i want to mount the solar heater on the roof; does that change the equation at all?

i like the idea of shut-off valves, though i was thinking about a valve that would isolate the collector, that is, one that could close the loop from the house water into the collector at all, temporarily returning the system to its original configuration. hmm, i suppose i'd need another on the hot water pipe coming out of the collector, too. i don't know that without one, air wouldn't get sucked into the house lines, or the solar heater wouldn't get too hot and do something creepy. you seem to suggest a shut-off valve that would turn off all hot water in the house, yes?

our climate is pretty warm with temps running from lows of mid to low 50s on dreary winter days (of which we have three all year) to highs in the low 100s on the worst summer days. average temps are 65-73 winter, 85-95 summer. (in 2005 we had the first snow here in 125 years.) so i'm not concerned about freezing, but my solar water heater may not do a great job in february.

cold temperature seems like the only reason i would have (other than occasional maintenance or repair) to shut off the solar heated water. is there something i'm missing?

TROY:
Here’s what I was thinking relating to shut-

i would like to install a solar water heater because my current electric one is on the north side of the house, near the kitchen and laundry, but the bathrooms are on the south side of the house. as a result, if someone wants a hot shower, they have to run a LOT of water before the hot water gets there. (i have given up washing my face in hot water at night in the winter.)

everything i've read so far talks about routing the solar heated water into the conventional tank. this would make my hot water cheaper, but it would still waste the same amount of water. i would like to install the solar heater on the south side of the house, near the bathrooms, and have it connect directly to the hot water pipes, thereby by-passing the electric tank entirely. is this possible?

i would like to install a solar water heater because my current electric one is on the north side of the house, near the kitchen and laundry, but the bathrooms are on the south side of the house. as a result, if someone wants a hot shower, they have to run a LOT of water before the hot water gets there. (i have given up washing my face in hot water at night in the winter.)

everything i've read so far talks about routing the solar heated water into the conventional tank. this would make my hot water cheaper, but it would still waste the same amount of water. i would like to install the solar heater on the south side of the house, near the bathrooms, and have it connect directly to the hot water pipes, thereby by-passing the electric tank entirely. is this possible?

Most estimates of hot water needs I see when reading about solar heaters are 20 gallons per person per day. That is an outrageous amount of hot water use even if you are home all day every day. Currently, our total water use is somewhere between 400 and 600 gallons per month for two people. We rainwater collect from a 1200 sq ft roof. Our area gets less than 20" of rain a year. Currently we are at over 80% capacity (4000 gallons or so) and the monsoon season is far from over.

20 gallons a day is, unless I can no longer count, 600 gallons a month per person just for hot water. We are at about 250 gallons per person total water use.

Yes, Gas heater cores work fine. You can mount them easily
(horizontally by putting a pipe through the flue in the middle and
securing the two ends of the pipe to supports. then no part of the
tank touches anything that would conduct the heat away.

I notice the article mentions using electric water heater cores. I
have two old gas heaters. Can those cores be used?

I plan to add the passive solar hot water tank to my home as seen
in your article. Due to the buildings position, space & sun. I
am thinking about housing my tank in a vertical position. I notice
that most of your examples are lying on their sides what is the
reason for this? Is it a mistake to place my tank in a vertical
position? Tara Cox

Hello I am very interested in your article. But, I'm wondering if
it's possible for me to have a similar construction during my
extreme winter (Lapland) weather conditions within the Arctic
Circle where temperatures are as much as -30 during the coldest
part of winter. As a novice I understand the basic principles of
your system but how would it function in cloudier or even days with
small light. Currently, I am looking at more cost effective ways to
heat my cellar which I intend using during the winter, without
splashing out too much money on heating bills. Electricity is
fairly expensive here and I need to create something like you have
to cut the costs. Any info or help would be much appreciated.
Thanks Andy

i need details about how solar heat becomes elecrtric energy ?

My Mom and Dad bought our family home in 1963. The house had been
built in 1923 and had a VERY old gas hot water tank that my Dad
replaced. He replaced a 40 gallon model with a 50 gallon model
because of our family size of 2 adults and 5 kids! That hot water
tank lasted at least 35 years for that was when we sold our family
home after my parents passed. The plumbing was such that there was
a 50 gallon storage tank BEFORE the cold water entered the standard
gas fired hot water tank. My Dad said it was free heat, the storage
tank raised the water temp to room temperature (70 deg. located
close to the furnace!) He also thought that the conventional hot
water heater lasted EXTRA long because it was never shocked by cold
water entering the tank.

I thinking of making a solar hot water tube for my swimming pool
15' Dia, A series of pipes going back and forth, water coming out
of the filter through the pipe work into the pool, the pipes and
backing being black with glass covering. could you tell me if i'm
on the right lines. Thanks Les cook

Lately I haven't been able to read the best magazine in the world
we live in but alas life is what you make it and I have gone in the
complete opposite of of live within ones means I will be getting
back there next year I hope. For a while I couldn't find you
anywhere I live on an Island in the northeast but travel every week
around the country of north and south america you would be
surprized but your magazine is only getting to about 20% of the
pop. maybe circulation should.