US hot water heater schematics and parts list needed

KenMorgan
KenMorgan Registered Users Posts: 92 ✭✭
in General Solar Power Topics #1

I was hoping that somebody can give me a diagram on how a normal US water heater is laid out including wiring diagram, thermostat/elements, and location of the over pressure valve etc. along with a parts list as well from one of the major manufactures.

I tried to get the navy exchange to order me an electric water heater, so i would have one that I could copy but on a large scale, but they are being their normal uncooperative self.

I am starting my quest to divert unused solar power to a hot water heater.  initially as a proof of concept and just to get my feet wet in this new endeavor i will be using a 500 gallon insulated water tank, that I will drill and tap for heating elements, sacrificial zinc, and of course the inlet/outlet & over pressure vent.  the inverter and water tank are on order so now I have to pour a pad, and start building.

this will be powered by a dedicated 5kw signeer 240 volt unit that i will be running via a timer control that allows for it only to operate during peak solar hours, and when the battery pack is above 54 volts (LiFePo4). This is after my battery packs have risen to >90% of their capacity.  With my data from the last year I can reasonably estimate a peak of 4 hours of water heating in the summer each day and 1.5-2 hours in the winter months with fall and spring sitting in between somewhere. 

I want to see how much heat i can store and how long it takes to heat the mean temperature of the water from ground temps of 16°c to 80 or 90°c.    I have run through the math several time using different calculators but it always devolves down to losses from the system as to how hot, and in what time frame, so at this point its time to build a system and get empirical evidence.

most calculators show about 38 hours of continuous heating at 4000 watts or 19 days when assuming 2 hours each day. this does not allow for losses which I am willing to concede could be quite high.  

the eventual goal is to expand the system if this works.
70kw LiFePo4 battery bank, 18 JA solar 200 watt panels, 20 sharp 200 watt panels,  morningstar controller(s) and a magnum 4448 inverter with all the usual junk that goes with it. 
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  • NANOcontrol
    NANOcontrol Registered Users Posts: 275 ✭✭✭
    #2
    500 gallons just to start..........

    You need to do way more research before spending money. No need to use inverters and heating from batteries is nuts. Yes everyone does it because they don't know any better.  Why go thru a charge controller and cycle a battery to just heat water.  Divert directly from panel array at lower current to reduce losses.
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  • m151
    m151 Registered Users Posts: 39 ✭✭
    #3
    If you are using a t&p valve and a sacrificial rod, this implies a 500 gallon pressure tank; This would cost a fortune! Even an atmospheric insulated metal tank would be a lot. $10 to 20k? I use a couple of used 50 gal water heaters as a tempering tank before the main water heater( thermal not pv). This would a cheap way of building a proof of concept. 
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #4
    m151 said:
    If you are using a t&p valve and a sacrificial rod, this implies a 500 gallon pressure tank; This would cost a fortune! Even an atmospheric insulated metal tank would be a lot. $10 to 20k? I use a couple of used 50 gal water heaters as a tempering tank before the main water heater( thermal not pv). This would a cheap way of building a proof of concept. 
    That is exactly how my thermal panel hot water system is setup, 80 gallon preheat tank plumbed in before the gas hot water heater, during 10 months out of the year I suspect the gas heater never fires up at all, the 80 gallon tank is set to 150F limit and a proportioning valve mix some cold in before it hits the main tank, roughly the gas heater is set to 115F and the feed off the 80 gallon is 125F ish to the tank.  A simple controller just measures the delta between the panel and 80 gallon tank and kicks on the circulating pump when the panel is over the tank temp. It makes tons of hot water. 
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  • m151
    m151 Registered Users Posts: 39 ✭✭
    #5
    Thermal is great for a DIYer. I see adds on Craigslist all the time for used equipment. People have a new roof put on or a small leak and no longer want to call an expensive plumber. I had a lot of enjoyment building my system and the payback is fast!
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  • KenMorgan
    KenMorgan Registered Users Posts: 92 ✭✭
    #6
    Xx xxxxxx xxx xxxxxxx x xxxxxxxx xxx xx xxxx xxxxxxx...... Gotcha.

    the inverter is taking off the top without taking from the batteries.  so no battery action here. system only energizes heating elements when the batteries are at 90%+ charge, time is in the correct window, and the thermostats request it.  any time the battery bank drops below 90% the water heater shuts off. 

    the pressure tank was ¥80,000 or about $625 USD at the current exchange rate used from the auction.  it is or was a stainless tanker lorry tank for transporting hazmat and was pressure tested to 4 bar or about 60 PSI when it was new.  (Japanese land law requirements for the type of tanker lorry it was.)

    my actual water pressure never gets above 20 PSI so only worries are if the water actually boils for this I need a pressure relief.  the sacrificial anodes are what i saw on a generic diagram for a 240 volt water heater and assumed i would need them as well for cathodic protection.  i also need to spray foam about 4" of foam on it after i weld in the bungs and build a small shed around it to protect form the elements in the winter.

    my system is over paneled by about 5 to 1 for summer use, this is due to my location & winter requirements needs.  to give you an example last week end, May 27, at night the night temps were a chilly 15°c at night and we used the split pack to heat the house. in the days prior to arriving the battery pack was at 73% (due to heavy rain the prior three days).  On Saturday morning when i awoke at 0600 my 30KW battery bank was down to 50% and yet was fully charged by 1130 that morning.  That was charging at over 115 amps at its peak before it started tapering off at the end of the cycle. so I have the power available, I have a tank that will suffice with the addition of welding a few bungs for elements, zinc and relief valves all I need is schematics (for the wiring) and parts numbers list. 

    this is a project I have been looking into for the better part of  two years, I have researched quite a bit of this including what cheap inverter vs tank etc to use.  I did not wake up yesterday with a wild hair up my backside.  I just have not been able to locate a parts list for a pre-existing electric water heater that i could order from for everything minus the tank.  yes it will take several weeks to heat up, yes in the winter it will drop down to if lucky a preheater for my existing on demand gas water heater, and yet if it all works out then it opens several doors for me to ramp up to full scale which is a 4200 gallon tank which I desire to construct.  little steps, little steps.
    70kw LiFePo4 battery bank, 18 JA solar 200 watt panels, 20 sharp 200 watt panels,  morningstar controller(s) and a magnum 4448 inverter with all the usual junk that goes with it. 
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