Expanding solar thermal system

Crazy Ivan

Hi all,

I had a search through the posts here and did some online research but can't seem to find the answers to two questions about my solar thermal system.

Firstly, I have a bank of 30 tubes on my SW facing roof and I love the system. It works so well over the summer months and I've saved so much money over the 12 years I've had it. However, I find the orientation isnt great. Even on summer days, if it's cloudy in the evening, I don't gain much from it. In winter, it barely sees the setting sun.

So here are the questions:

1) Is it possible to add another bank of tubes to an existing system (plumb it in series, or whatever)?

2) If you can add to the system, can you mount the other bank of tubes with a different orientation (more southerly)?

The gable end of the house faces almost exactly south and I'm interested in mounting a bank of tubes on the wall and plumbing them into the existing system, if that's possible. I'm hoping (🤞🏻) that this would help in winter, say. What I'm worried about is that I'll be heating on one array and then dumping heat on the other or that there are other issues I'm not fully considering.

Before anyone says "just get PV", I'm in a dormer and the back roof has limited space due to Veluxes and the thermal tubes so I'd have to go ground mounted. I have tonnes of space for that... Just don't have the money!

Many thanks for any help.

spose

If you are looking at mounting more thermal on the southerly roof then why not PV there? You can add in series, that’s basically how a lot of systems are built. As in the base kit is 10 or 20 tubes and you can mix and match to the size needed. Obviously they are usually right next to each other. Plumbing from one roof to another and back doesn’t sound too appealing though and for the summer then would you have a lot of excess that you need to be able to dump. Neighbour here managed to fit a full line of PV panels above the velux’s

redmagic68

https://www.boards.ie/discussion/2058261709/expanding-solar-thermal-system

As far as I am aware you need a second manifold and most likely plumbing back to the tank. Currently we are waiting to instal Pv panels on and east west pitch roof. I have 30 tubes facing east currently but seriously considering moving them to the south facing gable to take advantage of the better orientation. We have had them in 11 years now and find them great but I think with a better position in winter they would do even more than they currently do which is quite good.

Hoping to be able to use most of what’s there rather than purchasing new parts. Perhaps this might work for you rather than a second instal?

unkel

I've 40 solar thermal tubes myself. But in your case - it seems like you have lots of space - a ground mount solar PV system might give you more bang for your buck. A ground mount can be fairly simple, someone on here made one themselves just from whole trees. Look it up, it looks deadly and cost him feck all apart from the panels of course.

dathi

"The gable end of the house faces almost exactly south and I'm interested in mounting a bank of tubes on the wall and plumbing them into the existing system, if that's possible. I'm hoping (🤞🏻) that this would help in winter, say. What I'm worried about is that I'll be heating on one array and then dumping heat on the other or that there are other issues I'm not fully considering."

there are three ways of doing this

1, extend the pipework so that it flows from the header of original tubes trough header of new tubes .

2,plumb the new tubes into the old circuit with a 3 port valve which opens or closes depending on which set of tubes are hottest,

3,plumb the new set into the old circuit with an extra pump and non return valves

all the above will depend on the type of controller your system has as some of the basic controllers installed will not have the capacity to ad extra sensors to read temps in new tubes.

4, do as unkel says put in ground mount pv you can make a mounting system out of galvanised scaffold poles fairly handy

Crazy Ivan

Thanks so much for all the very useful advice. It seems that this mightn't be the best use of money at the minute. Maybe looking into PV is the right way to go.

I am stuck with ground mounted though. The roof space is just not there with all the windows I have. I'll have further questions on that but it's for another post as it will drive this one off the original topic. Thanks all.