How to Stop Insulated Shed with Solar Inverters/Batteries in it from Overheating?

blobert

Hello,

I've an unusual problem. While building a new build house (to passive standards) I build a "shed" to the side of it thats about 10-15m2 that's an odd triangular shape to fit in with site boundary walls.

I built this using SIPs to again a very high standard of insulation, the door is triple glazed etc. My rationale for this was I was going to put the inverter and 60kW of batteries for a large (circa 40kW) solar installation for the house into the "shed" along with our tools/bikes etc and I figured the batteries would perform better if they were not freezing in winter. So the heat from the inverter would warm the shed a bit and this would keep the batteries at a decent temp.

The problem is we ended up having 4 x inverters put in and even now in December they are kicking out a massive amount of heat. There's also currently zero ventilation in the shed at the moment so I'm having to keep the door propped open all the time to stop it from getting too hot.

My worry is in the summer it will get really hot in there to the point of everything overheating/shutting down/getting dangerously hot.

So I'm looking for a solution to this.

I'm thinking I need some sort of ventilation system that can kick in once the temp goes above 15 degrees (or whatever is optimal for the inverters/batteries) and try and cool the room back to that.

I'm guessing a number of fans up high that can expel the hot air up the top of the room while maybe a couple more fans are pulling in cool air from outside low down is probably the way to go. The advisor for the passive house talked about the benefits of stack ventilation (of having windows down low and up high) for moving air around so I thought it might work here a bit also.

I had initially thought of using heat exchanger units like this 

With the idea being that if I had traditional fan with big hole in the side of the shed that it would get too cold in there in winter. But it looks like that would not be an issue so I might be better off using somthing that is not doing any heat exchanging but just moving as much air as possible.

I'm looking for any advice on this. My walls are about 25cm thick. 2 of the walls of the shed are beside a wall (about 40cm away from it so in constant shade so might be an option for bringing in the cooler air)

I'm reluctant to put holes in the roof if possible so would ideally prefer to be venting from the top of the wall. Ceiling height is low, it's only about 2.2m tall.

Any advice would be much appreciated!

Thanks

GreeBo

The insulation will also prevent the summer heat from getting in, but you do need some sort of mechanism to remove the heat.
What the roof makeup?
the hot air will naturally rise up there, so venting there seems like your best bet.
Something like these roof cowls might passively do it, or you could add a powered one if you felt you needed more, at least you have the power onsite :)

https://fans4less.co.uk/products/natural-ventilation-roof-cowl-boat-loft-rain-hat-ventilation-extract-4-5-6?variant=13867337515077

If you really want to avoid holes in the roof, then duct from just below the ceiling into these cowls and out the walls, it might look a bit funny though!

ted1

is this a grid connected domestic installation?

The MEC for micro generation in 6/11 KVA. Your system is about 6 times larger. …..

blobert

https://www.boards.ie/discussion/comment/122942546#Comment_122942546

Thanks roof is sips panels as well with a PVC finish I think.

I'd really prefer not to go at the roof so would prefer to vent at the top of the wall.

Seeing as it's already roasting in there in the winter I think it's going to need quite powerful fans to move enough hot air out/cool air in.

It's actually a shame to be wasting all the heat from in there while paying to heat the house but I don't think there's any practical way to use the heat in there.

blobert

We have 3 phase power and completed NC7 process

We're allowed export up to 28kW if I recall

GreeBo

https://www.boards.ie/discussion/comment/122943806#Comment_122943806

If you have an apex then the top of the gable wall would be as effective as in the roof surface itself you could 90* out of the wall and then fix the cowl to that, especially if you do the same to both gables.

Lumen

This sounds a bit like an overheating greenhouse problem, for which the solution is auto-opening windows.

ted1

https://www.boards.ie/discussion/comment/122943816#Comment_122943816

That’s some system. Is it ground mounted ?

GreeBo

Otherwise, since you have "free" power on site, just stick some extractor fans in the walls and have them running during summer months, but your issue is going to be that they air they are pulling in is going to be warm anyway….

monseiur

As you are producing your own electricity so no big bills to worry about - a correctly specked air conditioning unit is the way to go