Backyard Aquaponics
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I'm searching for an appropriate pump for the solar pool heater panels.
Something that can handle hot water.
Something that can pump up at least 15 feet.
Relatively low flow.
110 v 60 cycle single phase power.
I'm searching but the best I'm finding so far are some of the hot water circulation pumps but they are kinda pricey and many of them won't pump up very high.b

I used a davy pressure pump to heat my pool. Its 250w and okay for temps up to 40d.
solar pool heater panels. What is it for. Hot water system it will have to be able to handle the temp. Heating a FT then it only has to deal with the temp of the water its pumping out of the tank not the temp of the return.

Its in TCL's thread - heating fshtanks. 250w is too much, only need a trickle of water @ 10m.

Second hand central heating pump and no doubt you will be pumping to the tank, that means you should be on the 'cool' side of the heat exchanger.

Since the water panels are old pool heaters, I don't know how appropriate they would be for heating system water directly. So I am planning to circulate hot water from the panels into an insulated container and use a coil of pipe to heat exchange with system water in that insulated container.

So, the pump needs to be able to handle relatively hot water. It doesn't need to pump very much water thought, I expect it would function on flows as low as 10-60 gallons per hour. Medium head of probably under 20 Feet.

TC

Ebay USA quick search on grundfos http://shop.ebay.com/?_from=R40&_trksid ... Categories
You're after a circulation pump. Just check the website for the specs if its not in the description.

TCL.... can't go past GRUNFOS pumps. Pricey .....yeh, I have got a grundfos circulation pump (3 speed)... circulates the water thru solar hot water heater and storage tank (in summer) & in winter it does the underfloor heating....will handle 100 degrees C (or about 200 F) no problems.....its about 14 years old.
My grundfos pressure pump (rainwater to the house) is 22 years old (repaired impeller twice) still going strong.

I use a shurflo to lift water 15 ft. to the solar collector on the roof of my biodiesel shed. It takes a suction on a reservoir that is not over 100 deg. F pumps thru panel and to a coil in my settling tank and back to the reservoir. In summer I raise the 55 gal of oil to 125 deg F in a day. I run it with an 80 watt solar panel so it runs when sun is up only. I have just put a rebuild kit in it after over 3 years operation. The model 2800 cost about $65 and the rebuild kit $28. It is available in 115volt from any RV supply house.
For AP i have a collector in the greenhouse set up to thermosyphon to a 50 gal HW tank. I wasnt getting enough heat so I put a shurflo 12 v. single fixture .pump in line to boost. It is is 12v. and runs from a 45 watt solar panel, rated at 1 gpm with zero head. It cost $45. I then circulate out of the HW tank to the fish tank coil with another model 2800 on the cooler side of the coil. Currently only heating one tank but plan to heat two more later on that is why the larger pump. These pumps are rated at max temp 130 deg F. I need more heat to the hot water tank and more controls before can stock talapia.

if you are circulating in a closed circuit, the pump does not need to overcome any head other than the pipe friction,
it only needs to move the water once the system is filled.
that is because it sucks and pushes in the same system.
just as much water is coming down, helping the pump as there is water pumped up by the pump.

it is only while filling the system that you need to overcome the head
that you can do from a normal water supply.
you need an expansion vessel to cope with the water expanding while temperatures rise.

frank

I think I need to allow this system to be an open system so I can allow it to drain down at night, otherwise I need to worry about freezing or fill the system with antifreeze of sorts. And then it requires being sealed and having an expansion vessel. I want to do this up quick and simple so open and drain down it will have to be then.

Spirit, I'll have to have a look at some of those pumps you mention. The peak of my roof is only about 15' high.

I would love to set this up as thermosiphon but the issues involved with putting a tank on my roof have daunted me a bit. I don't really have any good ground level location that would get enough sun to make it worth while.

The ebay list helps some but almost none of the listings have head or flow rate specs and trying to find that info on Grundfos site is starting to urk me. I type in a model number to their search feature and it does nothing!

I thought that there might be some confusion just after writing my post
by closed system I mean a system where water is circulated after the system is filled
that doesn't mean it cannot be open to the atmosphere.
any vessel on top will then serve as expansion vessel
with all the advantages of a "closed" system: no head for the pump to cope with

frank

Biggest trouble with closed system is the need to have the system filled before starting the pump. I plan to have the pump shut off when the sun goes down and to keep from freezing the water in the small tubes on the roof, I want it to drain down when water is not flowing. I think that draining down would not work for a closed system.

well, you can't have a gordy woman and lots of room in the bed, TCL
as I see it, you have several options:
one is an "empty" system that drains every time it is stopped
which means that your pump must overcome the head plus the friction not only every time you want to harvest solar heat, but permanently while you are doing so
such a system is also difficult to manage
because a thermostat will register the temperature of the "empty" system, not that of the water

the other is a "closed" system that is "permanently" filled
of course this system can be drained whenever there is a risk of frost
but then it has to be refilled
if you do that with an existing pressurized water supply, it will cost you no energy
only the water exchange
but it can also be filled with an anti freeze mixture ans stay permanently filled

frank

This set up consists of two solar pool heating panels (got these for free)
Insulated tank
Some tubing and fittings to get from tank to panels and to connect panels together
A coil of tubing to use for heat exchange with main system
And whatever pump I get for it.

No thermostat, the heater pump will probably run on a timer that I will have to manually adjust based on sunshine. I would love to run it direct off a solar panel but I don't get to spend that much on the project at this point in time.

I'm not sure how I would manage re-filling the system every morning over the next two months only to let it drain down each night. This doesn't really sound all that realistic for my situation right now. Now, I'm sure there are ways and ways to do this but some one would need to enlighten me to an easy/cheap way that doesn't waste too much water each day. I can't afford buying lots of automation stuff to make a smaller pump work.

Add propylene glycol in the circulation system, besides other benefits it is an anti freeze.