Greenhouse ventilation
Posted: Sun Apr 26, 2020 3:30 pm
The weather is set to cool to somewhere near normal (whatever that is, these days) next week and we may even get a bit of the wet stuff. This week, however, saw the temperature in the greenhouse peak at 46C which is pretty close to cooking the plants in there.
As the greenhouse is of cheap and cheerful construction, I can't go cutting holes in it to put in side louvres or wall mounted fans, so I'm looking at alternative means of pushing some air through it. I've looked at the solar panel powered fans that you can get but I'm not keen. Plonking an opaque panel on the roof of the greenhouse rather defeats the object of the greenhouse itself, plus I have low confidence that it would remain in situ over the winter with the fierce winds we get here.
My current thinking is that the simplest set up for me would be to have a 12V portable oscillating fan (the sort that can run from a car plug in socket, cigarette lighter socket in the old days) and a deep cycle leisure battery. We have surplus PV generation from the house array in summer and so rather than exporting it, I can charge up the batteries and they can sit in the greenhouse, powering the fan. How long they last depends on the power rating of the fan, but I'm after more of a continual gentle breeze than an all-day howling gale, so I imagine I should get a few days out of one charge based on a 7 hour operating day.
Other factors in favour of the battery/fan set up are that it can all be removed from the greenhouse as soon as temperatures fall in the autumn and it's no longer needed, and it comes in at about half the price of most of the solar set ups that I've seen.
Has anyone tried this system? I'll report back on any progress with the project, but I hope to have something going over the next couple of weeks for when the sun starts shining again after our long overdue rainy spell.
As the greenhouse is of cheap and cheerful construction, I can't go cutting holes in it to put in side louvres or wall mounted fans, so I'm looking at alternative means of pushing some air through it. I've looked at the solar panel powered fans that you can get but I'm not keen. Plonking an opaque panel on the roof of the greenhouse rather defeats the object of the greenhouse itself, plus I have low confidence that it would remain in situ over the winter with the fierce winds we get here.
My current thinking is that the simplest set up for me would be to have a 12V portable oscillating fan (the sort that can run from a car plug in socket, cigarette lighter socket in the old days) and a deep cycle leisure battery. We have surplus PV generation from the house array in summer and so rather than exporting it, I can charge up the batteries and they can sit in the greenhouse, powering the fan. How long they last depends on the power rating of the fan, but I'm after more of a continual gentle breeze than an all-day howling gale, so I imagine I should get a few days out of one charge based on a 7 hour operating day.
Other factors in favour of the battery/fan set up are that it can all be removed from the greenhouse as soon as temperatures fall in the autumn and it's no longer needed, and it comes in at about half the price of most of the solar set ups that I've seen.
Has anyone tried this system? I'll report back on any progress with the project, but I hope to have something going over the next couple of weeks for when the sun starts shining again after our long overdue rainy spell.