Green Building Forum - Filling Solar Panels

Filling Solar Panels

pmusgrove — Mon, 23 Jan 2012 21:09:30 +0000

I am about to fill my flat solar panels. Instructions from the manufacturers say "attach our panel filling pump". They then want Â£750 for the said pump! Not wanting to do this I am looking for an alternative method. At present I am looking at making my own pump set up but would welcome ideas from anyone who has already done this. Any second hand pumps out there already made up?

Filling Solar Panels

mattwprice — Mon, 23 Jan 2012 21:53:26 +0000

I think alot of people use a common garden pump spray for about Â£20....

Filling Solar Panels

wookey — Mon, 23 Jan 2012 22:23:05 +0000

Yep, garden sprayer is standard equipment for this job. navitron or eco-nomical and no doubt others will sell you one with a suitable adaptor to brass thread (remarkably good gear). And you can still use it as a garden sprayer or PUR-foam-setting-encourager once you cleaned the antifreeze out thoroughly.

Filling Solar Panels

owlman — Tue, 24 Jan 2012 08:39:15 +0000

Where in the country are you Paul?

Filling Solar Panels

pmusgrove — Tue, 24 Jan 2012 08:57:37 +0000

Wellington, Somerset.

Filling Solar Panels

owlman — Tue, 24 Jan 2012 09:06:43 +0000

A supplier near to me has one that he's prepared to hire out, but too far unfortunately. When I filled my system, and on instruction, I left the pump running for quite a long time to thoroughly flush the system for any debris and air, before finally pressurising. I've heard it can be done with a hand pump as wookey says but a bit tedious I would have thought, still if you've got the time.

Filling Solar Panels

dimengineer — Tue, 24 Jan 2012 09:46:00 +0000

You can always use a garden hose from your mains tap, to do the final pressurising. Most water suppies are at least a couple of bar and I found it vey simple to attach a hose to my garden tap, and connect the other end to the solar system.

Filling Solar Panels

tony — Tue, 24 Jan 2012 09:49:28 +0000

I did that too

Filling Solar Panels

owlman — Tue, 24 Jan 2012 19:27:51 +0000

I presume Tim & tony that you just pressurised to 2 bar. With my system, when flushing was complete, I had to take the pressure up to 6 bar to check all joints for leaks before finally reducing to operating pressure.

Filling Solar Panels

tony — Tue, 24 Jan 2012 19:31:41 +0000

mine went up to over 6 bars accidentally when I switched off the pump on a sunny day and it went up to 165C !!!

Filling Solar Panels

owlman — Tue, 24 Jan 2012 19:46:48 +0000

Do you have some sort of heat dump by-pass on the circuit?

Filling Solar Panels

tony — Tue, 24 Jan 2012 21:40:00 +0000

yes into my interseasonal thermal store now

Filling Solar Panels

wookey — Wed, 25 Jan 2012 02:32:07 +0000

If you pressurise with a hose how do you get the right fraction of antifreeze in?

Yes it is a bit dull pressurising with hand pump then going into loft to let air out and going back and forth a few times, but it's a trivial item after putting the system together. It is a good idea to have your bleed valve inside the loft and not on the roof, especially when you replace the antifreeze in 5 or 10 years, or have any other issues that require draindown (people quite often have problem with anti-thermosiphon valves that need fettling or replacing, for example)

Filling Solar Panels

Peter_in_Hungary — Wed, 25 Jan 2012 05:03:48 +0000

Posted By: wookeyIf you pressurise with a hose how do you get the right fraction of antifreeze in?

If you know the volume of the system (measured with a bucket on drain down or calculated) then its simple maths
Peter

Filling Solar Panels

owlman — Wed, 25 Jan 2012 09:29:43 +0000

I think your system must be slightly different from mine wookey. I simply have the collector on the bungalow roof and the pumpstation on the ground floor directly below in my boiler room with just the twin pipes between. I have the pumpstation,the controller, the pressure vessel, the overflow tank all co-located. I don't have to go in the loft etc., to do any bleeding of entrained air, I can control everthing from the boiler room.

Tony how does your interseasonal store work?

Filling Solar Panels

djh — Wed, 25 Jan 2012 13:24:59 +0000

Posted By: owlmanI don't have to go in the loft etc., to do any bleeding of entrained air

It's normal to have the bleed valve at the highest point, since that's where any air collects. How is your system set up to avoid that?

Filling Solar Panels

owlman — Wed, 25 Jan 2012 13:36:57 +0000

The pump station has something called AirStopp incorporated. I thought high point bleed valves and roof mount AAVs were a thing of the past.

Filling Solar Panels

tony — Wed, 25 Jan 2012 15:37:51 +0000

owlman

I pump any and all surplus heat from my solar collectors into the ground under the basement of my house in the hope that it will stay there till winter is over.

It works a bit and every little helps as I have no heating system in the formal sense

Filling Solar Panels

beelbeebub — Wed, 25 Jan 2012 20:04:27 +0000

my understanding (from watching the manufactureers videos) is that the filling station pumps fluid round the system at high speed to "flush" the system out and also to force through any air that is trapped in any air locks.

I know that an air bleed should be at the highet point in the system, but it is almost inevitable that there will be several inverted sections of pipe (possibly in the panel itself).

Just filling and pressurising the system won't get rid of these. Until they dissolve way and get bled out (which could take weeks or months) the flow rate of the system could be comprimised.

By running the fluid through at high flow rates and duping into the settling tank for any air to bubble out, before recirculating it would seem to be a good idea.

Of course the money asked for the filling stations is crazy (I was quoted Â£1200)

SO I came up with my DIY filling station.

What you need:

A mains powered drill (240 or 110), ideally with a "hold on" button - otherwise you have to use a cable tie
A plastic container something like this
A plank of wood to fit across the top of the box
A drill powered pump
Some hoses to connect from the pump to the solar system (I used some old washing machine hoses)
An RCD (to prevent electrocution - remember kids, water and electricity are not good playmates!)
A kettle, some tea bags, sugar and milk

Total cost, about Â£30 (assuming you already have a drill)

You screw the plan across the top of the box, up through the flange of the box.

Screw the pump to the plank and fit your drill (via the RCD)

Fit the hoses, one from the bottom of the box into the pump, one from the pump output to your solar system, and one from the solar system return back into the box

Pour some premixed solar fluid into the box, turn on the drill and watch the fluid get pumped into your system. As the fluid gets sucked away add more fluid. Use the hold button on the drill to keep the drill running, or use a cable tie.

At some point the fluid will start to splutter out of the return pipe back into your box, probably mixed with a load of bubbles. At this point stop adding fluid, the system should happily circulate with bubbles coming out in lesser numbers as time goes on.

At this point use the kettle, tea bags and milk to make yourself a cuppa, add sugar to taste

Keep going for about 15 minutes, occasionally topping up as required.

My drill pump produces a couple of bar static pressure, so I can pressurise by shutting the return valve and running the pump on a bit.

I'll try and take a picture and post, in the mean time here are some example pics.

Hope this helps

Drill pump example:
http://www.amazon.co.uk/WolfCraft-B2206-Super-Pump-Collar/dp/B0001P197C/ref=dp_cp_ob_diy_title_3

Plastic box example:
http://www.amazon.co.uk/Litre-Plastic-Storage-Box-Lid/dp/B001V5M3NA/ref=sr_1_10?s=diy&ie=UTF8&qid=1327521339&sr=1-10

Filling Solar Panels

wookey — Wed, 25 Jan 2012 21:22:57 +0000

Ass beelbeebub illustrated, you can avoid a high-level bleed by having a pump fill fast enough to bring air back down. Either scheme works.

Filling Solar Panels

owlman — Thu, 26 Jan 2012 14:09:33 +0000

BES are selling solar system filling units for Â£382.72 +VAT. A bit of an improvement on your figure Paul.

Filling Solar Panels

pmusgrove — Thu, 26 Jan 2012 18:15:26 +0000

Thanks Beelbebebub - I will give it a go. Or I may by a cheaper version and then rent it out afterwards; 10 rents and I will be in the money. Anyone between Exeter and Bristol want to rent a solar filling pump? Or go into partnership?

Filling Solar Panels

fostertom — Thu, 26 Jan 2012 19:03:35 +0000

Could be - will file that info.

Filling Solar Panels

pmusgrove — Fri, 17 Feb 2012 12:11:12 +0000

Made myself a pump set to fill the solar panels and it works! Used the system described above but went to the added expense of buying a "real" pump for Â£60 as I expect to be using it more than once. With advice from a CAT trained solar plumber (OK I admit it he did all the work) we have filled the panels and even on a cloudy day like today it is bringing heat into the tank for the first time. So we have a system that works available for anyone who wants to rent the pump, gadgets and advice in Somerset or Devon give us a shout.

Filling Solar Panels

Davipon — Fri, 17 Feb 2012 22:51:41 +0000

Hope your air bleed valve is isolated from the 'hot ' pipework by a good ball valve!
A decent filling station will rid the pipework of air and debris and give a realistic pressure test to all fittings and components.
Will also give your expansion vessel a tweak(don't forget to set the pressure!)

Filling Solar Panels

pmusgrove — Sat, 18 Feb 2012 18:37:59 +0000

Left the air bleed valve off for the time being to see if it is really needed. One problem I foresee is that I have an Akvaterm Solar Plus which to be efficient has a Laddomat valve to push the solar heat into a lower coil until it is up to 63 degrees when it goes into an upper coil as well. The problem is that when filling, the upper coil is full of air as it is on a blind loop. Got over it by tweaking a compression joint and hopefully got the air out. The pressure was tested by closing the outlet too quickly whilst the pump was still running. Hopped up to 4 bar plus and blew out of the pressure release valve. At least that works. The 750 litre tank has risen in just over 24 hours from about 7 to 20 degrees C in cloudy weather with a few sunny bursts so I am happy.

Filling Solar Panels

Davipon — Mon, 27 Feb 2012 20:25:24 +0000

Sounds good pmusgrove.
Would be worth checking pressure now, also look at PRV open pipe to check no fluid loss.
Blowing the PRV can cause some issues if the system hasn't been flushed through prior to filling and debris sits on valve seat keeping valve fractionally open.
I like to pressurise with air first, saves sticky moments if kit fails.
Another favourite pressure problem is not setting the Expansion vessel before filling.
Hope all's well

Filling Solar Panels

pmusgrove — Tue, 28 Feb 2012 21:11:11 +0000

Thanks for the advice. Pressure has stayed up well and I have been very impressed by the performance when we had a day of sun on Sunday. It got a 750 litre tank up to 52 degrees C. By "setting the Expansion" vessel do you mean attaching it and opening up the valve allowing fluid in? I have done that but have no idea if any fluid has made it that far. I am presuming that as I haven't found any leaks and the pressure has remained constant that all is well. The one thing that does concern me slightly is the fact the the panels (Worcs Bosch flat panels) had a white bllom in the middle of them when they got up to full heat in the sun. Any ideas why that might be?

Filling Solar Panels

Davipon — Wed, 29 Feb 2012 21:12:19 +0000

Sounds like possible condensation inside panel, might be worth contacting WB.
To set expansion vessel you need to know how much fluid is in the system and check with the table supplied to tell you the pre set pressure for that size vessel(supposedly calculated for your system)