Still puzzling over the solar hot water

At the start of the year I posted about us not understanding why the solar heat doesn't load the tank correctly. We still haven't managed to understand what is wrong. We have however got some thermometers which we attached to the three pipes and were able to tell a bit more from this.
We have emailed the installer again and also Akvaterm the supplier of the tank and the controller for loading the tank. It is frustrating because it means we are not getting the energy from the sun that we should.
Overall the system is great and the energy we do get from the sun is a useful boost to burning wood. It would be EVEN BETTER if we could get it to work properly though. The installation is a bit frustrating because the guy who installed it lives miles away so cannot just pop out to look at things. We have found 4 issues with it.
1) The pipes to the radiators were plumbed the wrong way round (so it took out from the cold end of the tank and put back in to the hot)
2) There was a leak in the solar circuit (and still is)
3) The heating controller isn't attached as per the Akvaterm instructions and was done incorrectly even for what the installer had intended
4) This issue we are looking at here where the solar energy is not loading correctly to the tank

This is some diagrams where I was trying to understand what the LK820 controller is doing.

This diagram shows how it should all be connected up. The heating on the right hand side isn't done quite like this as on here there is a 4 way valve that mixes from the top and middle puts back in the bottom to keep stratification, ours just takes from the top puts back to the bottom.

The solar hot water

We spent some time today trying to understand why the solar panels seem to heat the bottom of the tank then the top afterwards.

Our tank is an Akvaterm solar plus which has an additional coil to the Akvaterm solar tank. There is a controller shown on the diagram here as a sort of white cross near the solar panels on the red lines. This puts the fluid from the panels through the top coil when it is above a certain temperature, otherwise it just goes through the lower coil.

 

This is the controller. It has a fixed temperature at which is sends via one route than the other

This is the pipework for the solar input and the hot water output

This is all the instruction manuals for the heating

We have asked the installed what temperature the controller switches at, because as far as we can tell it almost always or possibly always loads in to just the bottom of the tank. It is not a problem as such, we are not losing energy it is just not the most efficient way as the tank needs to be hot at the top for the domestic hot water (shower etc). We bought the more expensive tank with the second coil to get this efficiency, so it is annoying if it never uses it for some reason.

Rain and sun

Poor Doug just popped out to move Bluebell and Lismore off the drive (where they have been doing a good job mowing) in to one of the fields and the heavens openned. It doesn't show in the picture at all but there were sheets of water coming down the valley. 

You can see from the lushness of the nettles that we have been having plenty of warm wet weather.

The solar part of the uber heating has been doing us well for showers  in the new shower, but we haven't had sun, except in short spells for some days

So we might need to burn the wood gasification boiler.

Cutting wood

We have quite a backlog of wood around the place waiting to be cut up neatly and stacked for dryng. Some is from when EDF put in the new electricity pylons and some from when Doug and team cut the trees on the road to clear them from the telephone line.

It is hard to find time to do this as Doug isn't allowed to use the chainsaw when he is on his own and when the help is there they do the house.

Again the lack of snow helped! We went skiing on Saturday, was nice in the sun but icy nightmare in the shade. So Sunday I did some things in the garden and Doug cut lots of wood.

And stacked it in our wood supply area. Stuff on the left is what we are burning now and on the right is partially some old crappy stuff we removed from round the house soon after moving in and partially lovely new stuff drying.

Here is another pile waiting for processing and there is some more that EDF cut and left ithe field.

Solar panels

I kind of mentioned it when I was talking about the heating, but the solar hot water panels are now connected up and generating heat. They were installed some time ago but have been covered up until now - and not connected to anything. They have raised the tank (2000 liters) by a few degrees each day it looks like. There were about 4 hours today that it was heating for (it was cloudy in the morning so startd at midday). The tank has been settling down and all coming to an equal temperature so we will see more clearly as time goes on. Of course at the moment we are not using any heat from it.

We hope to get the radiators working for a test run next week.

Free (ok not free - pre paid) heat!

Firing up the wood burner

The instructions seemed long and complex, but sure it is fine once we have done it a few times. There are a lot of dials and controls. Basically the whole setup isn't very complex, but it looks more so because it is important that water goes in to the tank at a level with similar temperature so that the water stays stratified with hot at the top and cold at the bottom otherwise we would have a large tank of warmish water rather than one which is hot enough at the top to provide water for showers. Then there are a number of pumps and dials for the solar hot water and for the wood burner.
The radiators are connected up basically but not fully yet.
The red tank you can see a bit of is the expansion vessel to cope with the water increasing in volume as it gets hotter. The grey pipes just right of center are the solar hot water going in and hot water coming out. The wood burner is on the left.

Lighting the wood burner

Control panel on the wood burner - tells you whether fans are on, temp of chimney (which is important I guess so that the boiler can control itself to achieve the correct temperatures and air supply to achieve gasification)

The super hot flame roaring down from where the wood is being heated to create wood gas above. The boiler is called a wood gasification boiler because it burns the wood very efficiently by gasifying the wood and then burning that gas

The tank on right is to provide flow if there is a power cut and the system is too hot and needs cooling - as we would have no water pressure at that point as our water is provided by a pump

Double skin chimney out the back

Heating is in (it is HUGE)

Look at the size of it! Although we did technically know the dimensions of the 2000 liter water tank, we hadn't taken on board just how huge it would be.

I am also wondering how on earth we are going to plaster the wall behind it... We could just leave it, but the hempcrete is quite crumbly and I imagine eventually it would all fall off, so we probably need to get a layer of something over most of it somehow. Maybe we could send a small child back there?!?

More photos in better light tomorrow, and we are getting a lesson on how it all works (plus I think there are a few final bits to do still). There are a lot of dials.

Excitingly the window man is coming tomorrow to deliver the windows too. Then fitting them next week.

Exciting progress

Here is the water tank 2000l ie HUGE. Quite a challenge fitting it under the beam apparently.

In the door is the wood burner - quite big

In addition there is a 200l expansion vessel to adjust as the volume of the water increases with temperature and a 300l emergency flow pressure vessel to provide cold water flow to quench fire in case of a power cut at peak temperature.

Will it all fit on the tiled area!? Also stress because the emergency flow vessel still has to turn up - due tomorrow. 

Exciting!