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This morning it is still 64F upstairs and 61F downstairs. No stove required again yesterday thanks to yesterday's solar heating from the greenhouse. I have left the single layer of shade net in place but still plan to raise it when it is sunny. To maximise the heat gain to the southern house wall. Which is protected by the 7m/22' x 2.5m/8', lean-to greenhouse.
The sun can't reach the greenhouse's brick floor in autumn and winter because of the front hedge. Which I shall continue to trim at around 6' high to keep it tidy and to provide wind protection and privacy.
As mentioned before: I need to thread a cord through the lower hem of the shade net. Then I can quickly bring the ends of that cord up to the greenhouse ridge. To retract the net to the ridge. Using the same fixing points at each end of the greenhouse as the top cord. The net probably provides very slight insulation if I leave it down overnight. Depending entirely on wind strength.I have no immediate plans for insulating the greenhouse in winter.
It will be interesting to see how warm the greenhouse becomes. As it get colder outside but still sunny. There is no point in opening the doors to the house if it is colder in the greenhouse. The raised temperature in the enclosing greenhouse will buffer the front wall against normal heat loss from exterior exposure.
I have been looking at making a solar absorption panel from empty cans painted black. The panel[s] would be standing against the southern wall of the house in the greenhouse. Normally such panels would be glazed and set up outdoors. With a fan pushing warm air into the house through a large duct.
In my case the greenhouse would provide shelter for the open panels without glazing. Pushing any useful heat gained into the house would probably require a fan in a window. There is the very real danger of drawing cold air, from outside, into the greenhouse with negative pressure. Such a low temperature, solar heating system works best by natural, unforced circulation. Warm air rises by convection to warm the house. Then cools and flows back down. To be warmed again.
My southern wall does not lend itself to the necessary, large scale ducting for this. Opening the windows or doors in the southern facade is all I have. The return of cooled air to the greenhouse would be very haphazard. At present, I seriously doubt the greenhouse will provide much heat. As it becomes cooler outside.
8.30 Sunshine. Enough waffling. Time for a walk. To the lanes and up the hill again. To confirm a westerly direction of the distant silos by compass. I also took photos to corroborate foreground buildings were in line. I saw lots of pheasants and a deer grazing on a winter crop.
The morning was mostly spent in the observatory. The greenhouse door was open to warm the house again. It is reported that Denmark is close to an all time record for sunshine this year. Autumn is forecast to be mild. All in our favour as the political parties fight over how much more taxpayer's money to give away to gas consumers.
The afternoon was spent visiting my British friend. Who gave me delicious cake and coffee. On arrival back at home I found a box with two slice of delicious cake. Left on the doorstep by a kind neighbour. I am being badly spoilt today! 😋
Had I left the doors open and it had clouded over, then the greenhouse would have drawn heat out of the house. My very simple solar greenhouse heating system needs human supervision. It is not a sophisticated passive solar anything.
19.15 Now considering what to have for dinner. Eggs with something? Salad? No salad. The carrots and cucumber were as soft as jelly. Worse, the carrots had black spots. Would you believe I can't manage fried eggs on toast? The non-stick frying pan isn't non-stick any more.
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