OK, I'm playing catch-up here, as our solar water heating has been in and working for a couple of weeks....
Solar water heating, or "solar thermal" as it's often called, captures the sun's heat using panels or tubes, passing it into a fluid - usually some kind of anti-freeze. This is then pumped through a coil in the hot water cylinder to transfer heat to it. I'll give some more details as we go...
We had it installed by Eco Hi Solar, who are based near Brighton. I can thoroughly recommend them, they were very professional and efficient. Here's a little plug for them:
The installation took two days. The first job was to get up on the roof, which was interesting to see how they did it:
They had a neat wooden thing with a pad of foam on the back, to make sure that no tiles or gutters were damaged:
Before long there were two ladders in place:
After which they installed a platform and fitted the manifold for the evacuated tubes:
Here's a view of the tubes fitted into the manifold:
We went for evacuated tubes rather than flat panels as the cost was about the same, but the tubes should work better in the winter. This is because they contain a partial vacuum, so reducing the heat loss when it's sunny but the air is cold. There's also the advantage that if a tube ever malfunctions, you can just replace them one at a time. The collector we used is a Thermomax HP200, which uses a heat pipe inside each tube to transfer heat to metal at the top of the tube, where water flows over it as it goes along the manifold, picking up the heat.
To connect through the roof, two lead panels were used to replace tiles, each with a small piece of copper brazed into it:
Once connected up, here's what it looks like on the inside:
These pipes are then connected to the hot water cylinder using this flexible stainless steel pipe:
With the collector installed, the next job was in the loft, connecting up the pump, expansion vessel, overflow container and valves used for filling and pressurising the system:
The pipes were connected to the cylinder in the bathroom, and then insulated:
They installed a pressure gauge in the bathroom as well as upstairs, so I can easily see that the system is still working properly.
The final key piece of kit is the controller. This detects the difference between the temperature of the hot water cylinder and the collector, and decides when to turn the pump on and off. You need this to stop the water being pumped round when it's cold or dark, and the heat being lost through the collector. Our controller can run the pump an anything from 30 to 100%, depending on how sunny it is, so improving efficiency.
Of course the other neat thing about the controller is it shows you the temperature at the bottom and top of the hot water cylinder, so we know exactly when we need to light the wood burner to add some more heat!
- Insulating the cavity walls
- Insulating the loft
- Flat roof insulation
- Insulating the dormer roof
- Sweeping the chimney
- Installing the wood stove
- Plumbing and testing the wood stove
- Installing off-grid solar PV (part 1)
- Installing off-grid solar PV (part 2)
- Off-grid solar PV upgrade to 750W
- Off-grid solar PV upgrade to 1250W