Navitron Renewable Energy and Sustainability Forum

SOLAR THERMAL => Solar Thermal Systems => Topic started by: linesrg on June 02, 2017, 12:56:19 PM



Title: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 02, 2017, 12:56:19 PM
Good Afternoon All,

Based on solar data from http://www.efficientenergysaving.co.uk/solar-irradiance-calculator.html (http://www.efficientenergysaving.co.uk/solar-irradiance-calculator.html) we get 872kwhr/ m2 annually.

Using the formula:-

Annual output (kWh) = 0.44 x annual horizontal solar irradiation (kWh/m2) x aperture area (m2) = 0.44 x 872 x (1.26 x 3) = 1450kWh.

For the month of May this gives a theoretical average output of 233kW. According to the software in the heat pump we've actually had 228kW which is a pretty close correlation.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Fintray on June 02, 2017, 08:43:25 PM
Richard

That's a useful amount of energy each day, isn't your system also using this heat for space heating via the thermal store?


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 03, 2017, 09:18:44 AM
Ian,

Yes all the energy goes into the EHS. At this time of year there is little demand for space heating. As I think I've commented elsewhere this leaves you with a 'deadzone' between 30 & 50 degrees in the EHS where you can't make any use of the energy.

More use will be made when the non-electric shower is installed next week.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on July 03, 2017, 09:00:57 AM
Good Morning All,

As I commented in the Solar PV section it has been the wettest June on record since 1910 up here in Scotland so not surprisingly both solar PV and solar ET output are down on expectations. According to the heat pump display we made 178kWhr against the 231kWhr forecast.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on October 05, 2017, 10:09:47 PM
Good Evening,

About two weeks after I went back to work i.e. the last week in July our system started producing some strange figures. Unfortunately through my being off California and my wife not really understanding the system an analysis of why this was didn't happen.

In early September I sent an EM to the installer detailing the problem as the heat pump was telling us we were producing silly amounts of kHr and this clearly wasn't happening. As it happened the heat pump manufacturer's representative was up in Aberdeenshire later that week and both were able to go over and look at the system.

They gave the system a once over and left having not determined the cause of the problem.

I got home last Thursday and having gotten various things done which needed doing I set about getting to the bottom of the problem myself.

I guess I'd better detail the issue. The Solar ET system circulating pump is meant to cut in when the temperature of the water in the system is 7oC warmer than the heat store. There was no doubting it was doing this. The pump kicks off at 100% and then modulates as it monitors the rate of temperature drop across the tubes.

Problem was the temperature wasn't reducing and the pump continued at 100% essentially continuously.

Switching the solar ET bit off and then back on did nothing. Switching the heat pump on and off didn't do anything either.

After a bit of head scratching this morning I pulled the insulation back from where the solar pipework entered the heat store and it was pretty obvious there was no hot water circulating anywhere - fairly obvious conclusion was that despite the pump running at 100% the system was clearly airlocked.

The heat pump determines the energy derived from the pump velocity and the temperatures recorded for the solar energy in and out of the tubes so as the temperatures weren't going down and the pump was running at 100% all the time clearly large figures would ensue.

I have spoken to the installer this afternoon and am waiting on a crew turning up with a charging rig to flush the system through.

I'm not sure how much useful energy has been 'lost' but on a relatively sunny day like today energy could have been gained in the heat store and used for the low level background heating currently in use.

I haven't named any names here and I'll leave you to form your own conclusions I know I have mine.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: dhaslam on October 06, 2017, 01:09:14 AM
It is always useful to have a flow meter in the system to make sure that there is proper circulation.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on October 15, 2017, 09:32:50 PM
dhaslam,

The system does have a flowmeter, it is hidden in the CTC Ecosol unit which is up in the Utility Room attic space and doesn't lend itself to being easily seen. In theory somebody should be coming around to sort the problem out tomorrow......................................

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: LA on December 14, 2017, 01:50:04 PM
Yes having read that I can agree with you there


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 19, 2018, 03:08:59 PM
Good Afternoon All,

I'm going to resurrect this thread iro the ongoing issues with my Solar ET system. Here I'm going to be asking for some specific guidance from the more knowledgeable persons on this forum. In saying I intend to look at my system before letting the installers back in I want to be sure of what I'm doing.

Having looked at the CTC Flowbox it is essentially similar to the unit Navitron sold at one point.

There are two connection points (both 3/4" BSP). One on the side of the safety valve (I must determine what this is set at) and the other immediately above the flow control underneath the pump itself.

Question No.1 - which connection do I connect the sprayer to? Logic tells me that it should be the flow control connection point.

I also need to check what pressure lies in the expansion chamber. Currently the system pressure is zero. It was at 2 bar at one point since I came home in September.

There is a 22mm pipe leading from the safety valve outlet to a 10ltr container - as recommended in the attached document.

I need an idiot's guide to checking the expansion vessel pressure. We have bicycle pumps to inflate as required.

Any comments/ advice over that already offered on the 'Show us Yours' thread appreciated.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 19, 2018, 04:48:01 PM
Good Afternoon All (again),

Grabbing this particular bull by the horns I'm looking into expansion vessels. I have found a spreadsheet on the Flamco Group site as at https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls (https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls).

I have entered the following information:-

1. 3off 4720AL contain 3.3ltrs of liquid
2. I'm calling the total pipework involved in the system 35mtrs which is all 22mm so equals 13.3ltrs of liquid.
3. Call the heat exchanger 0.1ltr
4. The top of the panels is no more than 3mtrs above the expansion vessel possibly nearer 2.
5. I think the collectors I have qualify as Group2 - difficult to drain???

Assuming I haven't made a simple mistake the spreadsheet tells me I need a 35ltr expansion vessel which is almost certainly larger than the one I have fitted. I'll need to eyeball the one I have.

Comments invited.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Mostie on June 19, 2018, 05:07:03 PM
I can't help you with setting the pressure vessel, however if its goosed (internally) it generally goes thud if you tap it, or a hollow sound if not, is the system pressure zero? if so has it escaped via the safey or in my case the air bleeder o-ring was leaking?


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Westie on June 19, 2018, 06:20:09 PM
Good Afternoon All (again),

Grabbing this particular bull by the horns I'm looking into expansion vessels. I have found a spreadsheet on the Flamco Group site as at https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls (https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls).

I have entered the following information:-

1. 3off 4720AL contain 3.3ltrs of liquid
2. I'm calling the total pipework involved in the system 35mtrs which is all 22mm so equals 13.3ltrs of liquid.
3. Call the heat exchanger 0.1ltr
4. The top of the panels is no more than 3mtrs above the expansion vessel possibly nearer 2.
5. I think the collectors I have qualify as Group2 - difficult to drain???

Assuming I haven't made a simple mistake the spreadsheet tells me I need a 35ltr expansion vessel which is almost certainly larger than the one I have fitted. I'll need to eyeball the one I have.

Comments invited.

Regards

Richard

The pressure vessel is sized in line with the coolant volume, your system has a lot of coolant because they've used 22mm piping. That was the recommendation when ST systems first came along but the advice soon changed to recommend  10mm as this reduced the coolant volume so it heated up more quickly, plumbing was also easier and of course the accumulator was smaller.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 19, 2018, 06:37:51 PM
Westie,

I have to be somewhat guarded in my replies on this matter as the installer, or one of his employees, could be reading what is posted and I want to ensure that I don't create problems for myself.

Anybody who has been following my postings on the Solar ET system I have will be well aware that things haven't worked correctly since Day 1. I think it is fair to say that the installers lacked experience in these systems, the fact that the system still isn't working properly after 18 months is simple testament to this fact.

My wish is that I end up with a working system and that the installers learn something from it. I can see I'll need to go back to them with the spreadsheet findings.

They have yet to respond to the EM I sent them this morning about successes people have had on here filling their systems with 'garden sprayers'............

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: dimengineer on June 19, 2018, 09:32:03 PM
An alternative way of pressurizing your system is to you the domestic mains water pressure. Every couple of years my system needs a top up, and I just connect the garden hose to bring it up to 2 bar. 20 minute job. I fitted a standard hozelok hose connector to the filling point.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 20, 2018, 07:45:35 AM
Good Morning All,

So my good lady wife, Kate, goes to the house yesterday evening to do a couple of jobs and grab me photo's of any ID sticker on the expansion vessel.

Well I do have some blurred and, in some cases, laterally reversed, photo's of a sticker on an expansion vessel. I now know not to make any assumptions. She managed to take pictures of the expansion vessel for the central heating.

I had thought it would be obvious which expansion vessel was associated with which system.............................

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: marshman on June 20, 2018, 08:01:33 AM
At least they were pictures of AN expansion vessel!

Roger


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 20, 2018, 08:07:44 AM
marshman,

There is that positive to take from it, she did also thank me for fixing the PSU for her MacBook................

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Westie on June 20, 2018, 08:34:54 AM
Good Morning All,

So my good lady wife, Kate, goes to the house yesterday evening to do a couple of jobs and grab me photo's of any ID sticker on the expansion vessel.

Well I do have some blurred and, in some cases, laterally reversed, photo's of a sticker on an expansion vessel. I now know not to make any assumptions. She managed to take pictures of the expansion vessel for the central heating.

I had thought it would be obvious which expansion vessel was associated with which system.............................

Regards

Richard

Hmmm...  If I asked my wife to take a picture of my expansion vessel I'd probably get told off and to act my age :hysteria



Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 20, 2018, 12:06:38 PM
Good Afternoon,

Progress of sorts, there will be a meeting with the installers once I get back onshore. The installers have, probably quite rightly, pointed out you do get different results in the spreadsheet if you elect to uncheck the box 'Can system partly go into vapour'.

In the meantime the system remains aerated...........

Regards

Richard



Title: Re: Solar Thermal Production @ Courtiestown
Post by: JohnS on June 20, 2018, 02:33:12 PM
Good Afternoon All (again),

Grabbing this particular bull by the horns I'm looking into expansion vessels. I have found a spreadsheet on the Flamco Group site as at https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls (https://flamcogroup.com/media/files/calculationtools/calc_eng_solar_v2016.xls).

I have entered the following information:-

1. 3off 4720AL contain 3.3ltrs of liquid
2. I'm calling the total pipework involved in the system 35mtrs which is all 22mm so equals 13.3ltrs of liquid.
3. Call the heat exchanger 0.1ltr
4. The top of the panels is no more than 3mtrs above the expansion vessel possibly nearer 2.
5. I think the collectors I have qualify as Group2 - difficult to drain???

Assuming I haven't made a simple mistake the spreadsheet tells me I need a 35ltr expansion vessel which is almost certainly larger than the one I have fitted. I'll need to eyeball the one I have.

Comments invited.

Regards

Richard

I have to admit that I have no experience with solar thermal, but a 35 litre expansion vessel for a circuit with a 16.7 litre volume sounds wrong to me.

John


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 20, 2018, 03:13:52 PM
JohnS,

With the information entered as suggested by the installer the spreadsheet produces a result saying a 12ltr tank is adequate.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Iain on June 20, 2018, 03:30:59 PM
Hi Richard
The expansion vessel is easy to check.
With no pressure in the system just put a pressure guage on the shrader valve to see what is in there. It should be about 0.2 bar below your designed system pressure. If you run at 2 bar set the EV to 1.8 bar. If it is too high, let some out. If too low pump some in.
The system can then be represurised to 2 bar.
The reason for the lower EV pressure is in case the system gets colder there is a reserve of pressure in the EV to keep the system pressurised. As the system heats up the fluid expands into the EV to stop the system pressure increasing too much and conversely if the fluid cools the reserve of pressure in the EV keeps the system pressure from dropping.
Mine  was set to 3 bar. With a system pressure of 1 bar, as it warmed up and expanded the EV couldn't absorb any of the pressure until it reached 3 bar, that was too late as the 3 bar relief was lifting and I kept loosing fluid.
I reset the EV to 0.8 bar and all has been perfect ever since.
Iain


Title: Re: Solar Thermal Production @ Courtiestown
Post by: desperate on June 20, 2018, 08:09:56 PM
JohnS,

With the information entered as suggested by the installer the spreadsheet produces a result saying a 12ltr tank is adequate.

Regards

Richard

12 Litres is plenty big enough for your EV, if your system contains 17 litres cold it will only contain 18litres or so when hot. Tell your installers that you MUST have a manual air bleed point at the highest place possible in the pipework, tell them also it needs to be a 15mm gate valve with a blank/cap on a short peice of pipe on the outlet side of the valve. Then via a garden sprayer pump you have complete control of the fluid and air within the loop.

Desp


Title: Re: Solar Thermal Production @ Courtiestown
Post by: dimengineer on June 21, 2018, 11:03:54 AM
JohnS,

With the information entered as suggested by the installer the spreadsheet produces a result saying a 12ltr tank is adequate.

Regards

Richard

12 Litres is plenty big enough for your EV, if your system contains 17 litres cold it will only contain 18litres or so when hot. Tell your installers that you MUST have a manual air bleed point at the highest place possible in the pipework, tell them also it needs to be a 15mm gate valve with a blank/cap on a short peice of pipe on the outlet side of the valve. Then via a garden sprayer pump you have complete control of the fluid and air within the loop.

Desp

Desp - I'm curious. Why a gate valve and not a ball valve?


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Tinbum on June 21, 2018, 11:08:53 AM
More reliable?  ???


Title: Re: Solar Thermal Production @ Courtiestown
Post by: desperate on June 21, 2018, 08:19:31 PM
Ball valves have a habit of leaking through the spindle glands when you use them after a long period of inactivity and you cannot tighten the stuffing nut like you can with a gate valve. Modern lever type full flow ball valves are a lot better, but they still rely on a nylon liner within which the ball rotates which I think are less heat resistant than an all metal gate.

Desp


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 25, 2018, 02:22:09 PM
Good Afternoon All,

Here's one for the steam enthusiasts amongst you....... >:( >:( >:( >:( >:( >:(

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: gb484 on June 25, 2018, 09:33:08 PM
hi, don't know if this is helpful, but a couple of thoughts on looking at your schematic in German and in particular, Abb 3 or diagram 3 about the Schwerkraftbremse or check valve. 0 degrees - funktionsbereit=normal position for operating system. 45 degrees - offen=this position for filling/refilling system, letting air out, flushing the system through. 90 degrees - geschlossen=closed. There's a note, Hinweis, below the drawings about the relationship of pressure, Druck, to temperatures when running, Betriebstemperatur. I suppose, basically, the temp should never go above 100 degrees nor should the pressure ever be above 10 bar in normal use. The values must remain inside the graph. There's also a little note at the top of next column about torque. Nuts should be tightened to the figures specified but may have to be retightened as seals settle with use. If I were refilling this, I would do what another member has suggested and connect a mains water supply to the union below the pressure gauge, where the 84 is roughly in the schematic, making sure that the check valve is in the open position as above.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 26, 2018, 01:50:41 AM
Good Morning All,

It's 0155 and the anchor handler I'm on is hanging around waiting to run the last anchor.......... what fun.

The boss of the installing firm is now taking a lead in this issue. He was around at my property this morning isolating the Solar ET electrically and sheeting up the panels. I'm advised that the intention is to look at the system today.

I remain slightly sceptical but hopeful at the same time. It's only been 19 months now.................

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 27, 2018, 08:41:04 PM
Good Evening All,

I'm not sure what progress has been made today but my installers advised they had been in contact with Navitron. They've reported that every time they fill the system air appears from somewhere in fairly short order apparently.

I should be getting of this vessel later this evening and should get home tomorrow morning and hopefully an update.

Even the Immersun is switched off currently.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: desperate on June 27, 2018, 09:06:25 PM
Good Evening All,

I'm not sure what progress has been made today but my installers advised they had been in contact with Navitron. They've reported that every time they fill the system air appears from somewhere in fairly short order apparently.

I should be getting of this vessel later this evening and should get home tomorrow morning and hopefully an update.

Even the Immersun is switched off currently.

Regards

Richard

Automatic air bleed leak ?

Desp


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on June 27, 2018, 09:18:07 PM
Desp,

I wouldn't be entirely surprised that the whizzo new air vent may not have appreciated venting off steam. It is rated to 180oC but whether it is meant to be subject to this for any great period of time I don't know.

Edit - I've just found this in Navitron's installation manual;

Important notice: We do not recommend that the automatic air bleed is fitted as shown in these diagrams (i.e.vent fitted at high point - my comment). If the panel goes into stagnation the temperatures that can be reached will destroy the auto air bleed valve. We recommend that the Spirovent auto airvent is installed low down on the return side of the system. A manual air bleed close to the manifold inlet is advisable. Once the system has been bled and commissioned the Spirovent will continue to extract any gases in the liquid.

This is the same source that specifies the diameter of pipework to plumb the system with in comparison to panel area so as 3 x 4720AL equate to 8.43m2 gross area 15 or 22mm can be used. I guess the smaller the better if only to reduce the volume of water which can absorb air in the first place?

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: dimengineer on June 27, 2018, 10:13:59 PM
Ball valves have a habit of leaking through the spindle glands when you use them after a long period of inactivity and you cannot tighten the stuffing nut like you can with a gate valve. Modern lever type full flow ball valves are a lot better, but they still rely on a nylon liner within which the ball rotates which I think are less heat resistant than an all metal gate.

Desp

Thanks for the explanation. I suppose I've always used high quality Ball valve - industrial quality, not domestic in my working life - things like Worcester and Swagelok on Water, Steam and Condensate. I'd always go for a ball valve, and dont think I've ever specified a gate valve in 35 years.
I guess it shows how different areas of engineering do things differently


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on September 12, 2018, 10:15:45 AM
Good Morning All,

This is something by way of an update on where we are with my Solar ET system. The installers have made somewhere between 3 and 4 visits, only one of which either my wife have been here for. The tubes had been sheeted since June through to a week ago.

The initial attempt revolved around seeing if the system could hold circa 3bar pressure which it did until the system was powered up at which point all pressure was lost and air could clearly be heard in the pipework.

I forwarded them 'advice' about dropping the system pressure to 1bar. I didn't get any reply to this but the next time I observed the gauge this appears to be what they did.

When I got back from my last job offshore the sheeting had disappeared and the pressure was back down to zero.

Yesterday was quite sunny and the system was operating but had me scratching my head.

Firstly it has to be said there as no sound of aerated water when the system kicked off so that has to be a positive. The way it was operating was different to what I've observed before (short cycling) but this might have been due to the presence of high cloud and not enough energy available. Later in the afternoon when there was less cloud saw it operating for longer periods.

I switched the GSHP on to 'Automatic Heating' as an experiment and it put the EHS to 'Active' and used the energy in the EHS to circulate the central heating. That's the system functioning as it is meant to along with the Immersun diverting Solar PV energy.

I used the EHS to heat the DHW as well just after lunch. Following my shower last night the EHS was pulled down to 40oC before the GSHP cut in to finish the DHW heating.

Overnight the EHS has been pulled down to 27oC as it has given up energy to the central heating meaning the GSHP compressor was running this morning to provide heating. I've switched it off as I don't really need it.

Currently the sun is working its way up and around. The Immersun is diverting Solar PV to the EHS and I'm just waiting for the sun to fall on the Solar ET although we have a thin high cloud again (cirrus).

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: stannn on September 12, 2018, 11:30:01 AM
I never pressurise to more than one bar and, yes, the presence of cloud slows heat collection dramatically.
Stan


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Tinbum on September 12, 2018, 12:04:25 PM
These systems can be very frustrating. My system has been working perfectly but did have a very small leak but it was minuscule. This year it went into stagnation and I re pressurized. A couple of weeks later it did the same. I pressurized and it did the same again. Can I find a leak- no. I wondered about the coil in the cylinder but it can't be that as the DHW pressure is higher. I'm baffled. It can't be the expansion vessel as i could have filled that up many times over.  ???


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on September 12, 2018, 12:13:16 PM
Good Afternoon All,

As I type this the Solar ET pump is running at 100% and there is some pressure showing on the gauge as per the attached photo. Still no sounds of aerated water.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on September 15, 2018, 12:45:16 PM
Good Afternoon All,

As it was a pleasant morning I went out and attended to some minor jobs with the Solar ET. I've lagged the air ejector, tidied up a couple of bits disturbed by the installers installing/ removing the protective sheeting.

Whilst up there I noted that the way the installers had strapped the pipework to the wall left something to be desired. As can be seen the internal ribbed pipework is visible at one point. I re-attched using the same strapping but with a bit more slack.

The other day the whole system was working as intended i.e. the Solar ET was heating the EHS, the Immersun was diverting the Solar PV to the EHS and the heat pump was using the EHS to provide domestic heating and then the E159 error re-appeared. This time I left the USB until the following day and then sent the data to CTC. This has allowed them to identify the software error. This error wasn't occurring prior to the last software update. The installers have been tasked with coming around and uploading some revised software.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on March 15, 2019, 07:43:50 PM
Good Evening All,

Clearly I have too much time on my hands whilst stuck out here waiting for the bad wx to blow through this weekend. There are still 'issues' i.e. no pressure with this system although it was functioning whilst I was home last time.

The picture below is one transferred from the Heat Pump Install thread and would appear to show quite clearly that the expansion vessel for this system is anything but mounted below the level of the pump in the adjacent pumping unit as would appear to what different installation 'manuals' I've been looking at on the internet advise is correct.

One job on my list when I get home is to see if I can shuffle the pumping unit up some and shuffle the expansion vessel down (the latter I know will be limited by the need to access the Schraeder valve on the bottom).

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: rogeriko on March 15, 2019, 08:21:26 PM
You need to get a little pressure in there. Just use a garden hose and give it a squirt of water, probably one second will do the trick.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on March 15, 2019, 08:42:40 PM
rogeriko,

I can only hope it will be that simple. Whilst the panels were sheeted up last year the installers did have it pressed up to 1bar and the pressure held for several days and was 'lost' shortly after system start-up.

Kingspan Varisol installation instructions state that - 'The expansion vessel must be located below the level of the connection from the pump station.' If you check out Section 7.10 of the document at http://www.solarpanelsplus.com/pdfs/installation-manual-2.pdf (http://www.solarpanelsplus.com/pdfs/installation-manual-2.pdf) you'll see a pretty crappy picture but one that clearly shows the expansion vessel clearly mounted below the pumping unit.

I'm not a plumber but if industry guidance tells me that is how an expansion vessel ought to be mounted who am I to disagree and I have to go through a process eliminating all possible causes of the problems with my system.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Tinbum on March 15, 2019, 08:49:45 PM
I eventually found the problem with my system which turned out to be a leak inside the header of one of the panels. Solved it with central heating leak fix from screwfix- local and was going past anyway. No problems since and the leak was pretty large in the end.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: rogeriko on March 15, 2019, 09:41:43 PM
The expansion vessel must be below the filling point with the pipe going downwards so when you fill the system there is no air in the pipe and the air on top of the bladder can rise and escape. Obviously there was air left in the pipework from an incorrect install. Take the pressure vessel off the wall and put it temporarily lower down and then give the system a shot of water. Just remember when you connect a hose pipe the pipe must be full of water, no air in the pipe or you are just putting air in the system. Is there an air vent somewhere on the system? If the pipe has filled with water and the air has escaped then all will be well next time you fill it. If there is air going around the system you are going to have to have the system refilled properly. Easy to do I can tell you how.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on March 16, 2019, 01:06:08 PM
rogeriko,

I'll revert once I've had a go if necessary, thanks for responding.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on March 22, 2019, 09:48:47 AM
Good Morning All,

Apart from the still obvious sound of air in the system and no pressure there Solar ET system appears to be functioning still. According to the heat pump we've made 69kW from it.

I'm still aiming to do some work on this system but there are only so many hours in the day (going in and out of Aberdeen twice yesterday didn't help).

Following something I read at one site I've reduced the flow rate from the maximum 6ltrs/ min set by the installers to 4ltrs/ min on the basis of 1ltr flow for each square metre of panel. Hopefully this will make the system more efficient by increasing 'residence time' or whatever the correct technical phrase is.

Regards

Richard



Title: Re: Solar Thermal Production @ Courtiestown
Post by: daveluck_uk on March 22, 2019, 11:43:38 AM
Richard, are your panels lower than the water you are heating and is the store open vented and is your hot water non direct? If it is you could go non sealed.

Remove all the pressure tanks and feed in loop. I've been running mine like that for a while now and have made it through the winter with no freezing issues and I've not had any air problems at all.


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Iain on March 22, 2019, 11:49:56 AM
Hi Richard
Just for a comparison.
I have 20 x 65 mm tubes. My pump is on the lowest speed with variable speed control.
It starts on 40% of the low speed and only on a couple of occasions have I seen the speed raise to 90%.
Probably a silly question and probably been mentioned before.
I had problems at the start with air etc. I finally narrowed it down to the Expansion vessel. I comes prcharged to 3 bar. I run my system at 1 bar so there was nowhere for the expansion to go apart from the pressure relief valve. As the system cooled the volume reduced an therefore drew a vacuum and any weak area would let air in.
I reset my EV pre charge to 0.8 bar for a 1 bar system pressure.
Not had any problems since.
Is your EV set to the correct pressure?

Iain


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on March 22, 2019, 05:38:33 PM
Iain,

My pump is also variable between 0 - 100% but the software allows the upper limit to be altered which is what I've done, so 100% = 4ltrs flow.

As I have posted previously I have allowed the installers to work on the system so far and thus I cannot answer your question. I am hoping that during the next leave I will get some time and the enthusiasm to start on the system and I'll be finding out what the current pre-charge pressure is.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on April 09, 2019, 05:36:11 PM
Good Evening All,

Well we've had a nice sunny day here and I am genuinely pleased to report that the Solar ET continues to look like it is behaving itself.

I have attached a picture showing the system was 'pressurised' whilst operating this afternoon and I have witnessed it doing its panel cooling bit when the manifold gets to 120oC.

The EHS has had a lot of energy input via both the Immersun and the Solar ET and is currently sitting at 78oC which will get used later for domestic heating as the system demands.

Fingers crossed.

I do still intend lowering the expansion vessel.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on April 29, 2019, 10:52:57 PM
Good Evening All,

As the system went into something less than 100% functionality today I have finally decided to set about this system.

I have raised the pumping station a couple of inches and lowered the expansion vessel a similar amount.  I have no idea if this will have any impact but it is a start.  It also allowed me to discover that the installers found it necessary to secure parts to 19mm of plywood using 70mm screws.............. I can't say I'm surprised.

I've lashed together the garden sprayer and an old washing machine supply hose and injected a (small) quantity of fluid and circulated on two occasions.  At the end of the first session the pressure had dropped to zero but I have left it with about 0.8bar currently and will monitor the system as it bursts into life tomorrow.

I have also lowered the temperature at which the manifold cooling function cuts in.  It was 120oC and is now set at 100oC as this is the lowest setting available.

Next I need to work out how to check the current pre-charge pressure of the expansion vessel.

Regards

Richard

  


Title: Re: Solar Thermal Production @ Courtiestown
Post by: Iain on April 30, 2019, 06:35:43 AM
Hi
Quote
.Next I need to work out how to check the current pre-charge pressure of the expansion vessel.
 

Just wait until your system pressure has dropped to zero (if it does again) and check the pressure in the EV with the Schrader valve.
Or just vent the system pressure away one evening, test the EV precharge, reset if required, and then recharge the system.
I run my system at 1 bar with a precharge of 0.8 bar.
Just have the precharge 0.2 bar below system pressure. (With a cold system)
When testing the precharge just ensure the is no system pressure to affect the reading.
Can you also see the outlet from the Pressure relief valve?, normally goes into a tun dish. On mine there was always a drip of water sitting  there, showing the PRV had been operating. My PRV  is a 3 bar one. I believe some are higher which allows a higher system pressure/precharge if required.

I have found 1 bar works fine though.

Iain


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on April 30, 2019, 08:59:06 AM
Iain,

Thanks for this.

The system made lots of air related noises on start up this morning but, to be honest, I expected this.

I'm tiptoeing around this at the moment as I am simply unfamiliar. There is no rocket science involved I know but when you haven't even removed the rubber protection cap on an EV before.......

Next up is determining the best means of checking the pressure within from the equipment I have available or whether I need something more 'dedicated'.

I'm going to be in all day and will very closely monitor the system and intervene if required.

The good news is we aren't in a fault mode which is where we were yesterday at this time.

Late Extra - OK so the system is operating, after a fashion, but the EV has a pressure circa 1.6bar currently with a system pressure of around 0.2 - 0.3 bar. I'll need to leave it for now and look to bleed some pressure off the EV this evening.

Regards

Richard


Title: Re: Solar Thermal Production @ Courtiestown
Post by: linesrg on April 30, 2019, 11:44:42 PM
Good Evening All,

I'm just back from some kayaking down the Don and dinner at the flat and launching myself at the Solar ET.

The system pressure is showing as zero on the Flowbox gauge and the temperature in the EHS only reached 61oC today so it was a stress free day as far as the system was concerned. The Immersun did't start diverting until around 11 o'clock and it got slightly cloudy later in the afternoon.

Enough of the burbling - I've just put a tyre gauge on the EV and it is actually showing 34psi rather than the 24psi I thought I saw earlier. This suggests the EV retains the pressure it was originally supplied with i.e. best part of 2.5bar?

I bled the EV down to 12psi which is near enough 0.8bar and I've pumped more fluid into the system and the Flowbox gauge is now showing 1bar and I'm circulating at 50% pump speed.

I have to go away for a few days so won't be able to closely monitor things - I'll just need to keep fingers crossed.

Regards

Richard