Plumbing Solar Storage Tank

Discussion in 'Solar and Geothermal Water Heating Forum' started by ARSolar, Sep 22, 2009.

  1. ARSolar

    ARSolar New Member

    Messages:
    7
    Location:
    AR
    Hello All,

    This is my first post on this forum and I must say I'm very impressed with the expertise I've seen here.

    I'm currently connecting my first closed loop glycol solar hot water system. This system is rather complex in that I will be feeding two existing hot water circuits from one 80 gallon Solaraide storage tank where the heat exchanger is mounted. This 80 gallon tank will be feeding the two circuits each having a 50 gallon electric water heater currently. The 80 gallon does have a top element for backup if needed.


    To picture this system better I have the 80 gallon storage tank sitting about half way between the two 50 gallon units with separate circuits. The two 50 gallon units are about 60 feet apart. My idea is to not run two backups but feed the East and West circuits either with the 80 gallon backup element or use the West hot water heater to feed the East circuit. The question I'm having is the West hot water heater circuit runs into 1/2 inch copper about the last 25 feet finishing about the mid point in the house (I'm working from the crawl space). Should I tap on to this 1/2 inch copper existing house circuit or not think of running the West water heater as a backup for the East circuit and place a T under my 80 gallon tank and use its top element as backup for both circuits? Another issue is capacity and pressure coming from the 1/2 inch copper feeding the East side of the home. The East circuit has the kitchen and utility room where you will find the dish washer and washing machine and a 1/2 bath. Any suggestions?

    Sorry for such a complex post but this install is not your typical install.
    I look forward to your opinions.

    Thanks Guys!!!!
    AR
  2. you lost me at hello

    you lost me at hello.....


    how big is your house???

    how large are the two east + west tanks....

    if you have the room
    would it be wiser to bring them to a central area
    near the 80 gallonsolar tank???

    why dont you draw something
  3. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    A drawing schematic would be much more useful.

    I can't understand if you are keeping the two 50 gallon elelctric units and preheating the water to them from the new 80 gallon tank or just tying in the pipe work from the two 50 gallon tanks removing the tanks and running the pipes back to the 80 gallon tank.

    That would seem to be me the sensible thing to do as it looks like you have a 3/4" feed from the 80 gallon tank and dishwasher and washing machine won't draw too much and running two showers simultaneoulsy should be fine as long as your supply pressure and hot and cold feed (particularly)is 3/4".
  4. ARSolar

    ARSolar New Member

    Messages:
    7
    Location:
    AR
    That is a great idea. What program do you guys use to make your drawings?

    Thanks a Million!!
    AR
  5. ARSolar

    ARSolar New Member

    Messages:
    7
    Location:
    AR
    Thanks for your post Flamefix!! I greatly appreciate your input. I see that you are in England. I've been there twice and you have a very beautiful country!

    I hope I've answered your questions from my previous post. I'm looking into the best program on my new computer to make a schematic for you guys. I'm planning on leaving the two water heaters in their places since I've installed the new solar storage tank in a unused closet. I hope you can make sense of my ideas from my last post.

    Thanks,
    AR

  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    heater

    quote; The two 50 gallon units are about 60 feet apart. My idea is to not run two backups but feed the East and West circuits either with the 80 gallon backup element or use the West hot water heater to feed the East circuit.

    That is completely confusing. You are NOT using the solar element or the two tanks as backup, according to what you imply. You are using the two tanks as primary sources and the solar heater, not its element, are the backups when the tanks are depleted. The backup element is a fall back fail safe source of energy when the solar element is inadquate to maintain the temperature in the 80 gallon tank ONLY.
  7. flamefix

    flamefix New Member

    Messages:
    71
    Location:
    Exeter, England
    I'd just use a pencil and paper to draw it and scan it up.

    Why don't you buy another solar cylinder, rip out the two existing cylinders and pipe the solar to both cylinders either split or two separate solar feeds. Use the electric as your top up to ensure adequate storage temperature of hot water. Saves you a lot of ball valves T's and doesn't require great changes to your existing pipe runs, and as your existing cylinders are old anyway makes long term sense.



    Yes England can be very beautiful but there are good and bad sides too. Fortunately Devon is a lovely place, shame this county is run by uninspiring mindless morons without a plan, otherwise it would be a great place to live. :)
  8. ARSolar

    ARSolar New Member

    Messages:
    7
    Location:
    AR
    Thanks for the input guys!!

    Sorry if my description was a little vague. One of you was correct in saying that the existing east hot water heater (the oldest unit 1971 model) will not be in use after this installation.

    The main question that I had originally was if I could run my east circuit off my west circuit via a 1/2" copper existing line. Later after reading some post, I concluded that this would be a bad idea since two people or appliances using this 1/2" line would cause low pressure.

    This has prompted me to hook the east hot water circuit directly to the 80 gallon solar storage tank via 3/4" copper. This 80 gallon tank will be feeding both the west and east hot water circuits in the home.

    The kitchen is approx 50' east from the solar 80 gallon tank and the west hot water tank is 16' west of the solar storage tank. The west circuit has all of the showers and bathtubs (4 full baths).

    I hope I have explained things a little better. What option do you guys use to post photos directly in text on this forum?

    Thanks again for all of your ideas!!
    AR
  9. Alphacarina

    Alphacarina New Member

    Messages:
    26
    Location:
    Biloxi, MS
    It sounds like your solar system is just a preheater for your two 50 gallon tanks - You're never actually going to shower using solar heated water . . . . you're just hoping your 50 gallon tanks will be heating up 75 degree water as opposed to 60 degree water they would normally be heating if you had no solar system. Unless your current 50 gallon tanks are SUPER insulated, your thermal solar gain will be largely LOST by the heat radiated away from your three tanks holding 180 gallons of water . . . . . heated I assume by a single collector on the roof?

    You can't heat 180 gallons of water for a 5200 sq foot house with one teeny tiny solar collector - What you really need is about 3 of the 4 by 10 foot collectors feeding a pair of well insulated 80 gallon tanks . . . . and then toss your two 50 gallon conventional tanks. With the system as you describe it, I really don't see you ever getting your money back from your solar investment - Energy wise, I think you would come out ahead just using flash heaters which would get rid of the heat you're wasting by trying to store 180 gallons of warm water

    At any rate, lots more thought needs to go into this before you buy anything because what you're describing isn't the way to go, that's for sure

    Don
  10. ARSolar

    ARSolar New Member

    Messages:
    7
    Location:
    AR
    Thanks for the input Don. I may have been a little vague in my original post. What I was really asking was a plumbing question and not so much a solar technology question. The system will not be heating 180 gallons of water only 80 for use in the two circuits. Since I'm not a plumber and am learning a lot about copper fitting and how different size copper works in circuits I was really wanting to know how a 1/2 inch copper line would feed my 2nd circuit. I read on and found the answer. The 1/2 inch would not do the job with two appliances in use (dish washer and clothes washer), the pressure would be too low.

    Given all this, I am running from my 80 gallon storage tank (with upper element) to my east circuit (kitchen, utility, and 1/2 bath) with 3/4" type L approx 50 feet. This runs from a T at my 80 gallon storage tank. The existing east water heater will not be in use. The second exit on the T will feed 16' west to my new Bradford White 50 gallon water heater BUT will have three ball valves to bypass the water heater during the 9 months of high solar reception. (This is what most folks do on many systems around the country). If needed, the West tank (new Bradford White) can be kicked on at the breaker for the cloudiest three months of the year.

    The system is comprised of 2 - 4' x 6'10" Heliodyne flat plate panels to supply through 4 persons in the home. The home generally has 3 and on rare occasions 4 persons residing. If the system needs expanding someday, a 3rd panel can be added on the roof and a 120 tank replacing the 80 gallon with the original controller being used.

    I hope I have explained this somewhat complex install a little better.

    Thanks again for everyones input. I'm not the best writer at times in making descriptions so you all will have to forgive me on that :) I hope to have photos soon.

    AR
    Last edited: Oct 1, 2009
  11. Alphacarina

    Alphacarina New Member

    Messages:
    26
    Location:
    Biloxi, MS
    You're going to be wasting a lot of water, both hot and cold by using a 50 foot long 3/4 inch hot water feed to your kitchen and laundry room. 50 feet of pipe holds a lot of cold water before any hot water will get there . . . . and then when you're done, a lot of hot water will be sitting in that big, long pipe to get cold before you need to use it again. If I'm not mistaken, 50 feet of 3/4 inch pipe holds about 3 gallons of water . . . . and it will all be cold water running to your sink, dishwasher and all until you've used more than the initial 3 gallons

    A modern dishwasher (and for that matter, a modern clothes washer as well, assuming you have a high tech front loader) use so little water that it's frequently not practical to run a long line from the centeral water heater to the appliances . . . . even if it's a 1/2 inch pipe - A 3/4 inch pipe would be even worse. The first gallon or two will be the cold water stored in the pipe (even more than a couple gallons if you use a long 3/4 pipe as you propose) so that when the final gallon or two of hot water does get there, the overall result is an appliance using a mixture of a couple gallons of hot and two or three gallons of cold water . . . . and then another few gallons of hot water will be wasted when left to cool off in the pipe after the appliance(s) are finished operating

    My house uses 95% solar heated water for everything (no additional heat applied to it for about 10 months of the year) except my dishwasher and my clothes washer - Both are about 35 to 40 feet of pipe away from the heated water storage which really makes the long hot water runs of pipe impractical (and I'm using 1/2 inch pipe) so I use two small electric water heaters for those infrequent tasks

    The one in the laundry room is a high efficiency 6 gallon unit supplied with 120 volts on a 60 minute manual timer. We turn on the water heater about 15 minutes before we start a load of clothes (only those few loads which require hot water) and then it gets hot water to the machine immediately when it calls for it . . . . no pipe full of cold water to empty first. There isn't even a hot water pipe to the laundry room at all - It's out in the garage

    Under the kitchen sink and about 1 foot away from the dishwasher we have a similar heater, but just 4 gallons and it is plugged into 120 volts 24/7. The wife really loves it because when she needs hot water at the sink, it's there immediately and 4 gallons is plenty for most things she needs and it's also more than the dishwasher needs. Your wife will be running 3 gallons of cold water down the drain before she gets any hot water at all. The input water for my undersink heater comes from the solar hot water tank so that if you wanted two sinks full of hot water, it's no problem, because long before the initial 4 gallon fill is used, the hot solar water is there to keep things going

    You can simplify things by using runs of 1/2 inch pipe and making them as short as possible . . . . and just not running the dishwasher and the laundry at the same time - Something which would very infrequently happen in real life anyway. The only 3/4 inch copper in my house is the main cold feed which supplies cold water to all uses plus the water heaters - All hot pipes are double insulated 1/2 inch copper and I've never experienced a loss of pressure at any appliance so far. Even if your dishwasher or clothes washer DID experience low pressure, they would still get the proper fill . . . . the input valve would just remain open longer until the correct amount of water fills the appliance

    I cannot imagine the need for a 3/4 inch hot water feed to anything and the disadvantages sure outweigh any perceived advantages in pressure or flow, IMO

    Don
    Last edited: Oct 2, 2009
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