Heat

The last couple of days have been particularly difficult.  A weekend, but it might as well be a week day as I can’t do anything that I had planned anyway – too hot.

So I decided to run some tests, to see what is going on.

First, current Bureau of Meteorology reports:

Frankston 19.6oC, Cranbourne 21oC, Melbourne 27.5oC

Local temp in the backyard: 35oC.  And this is not the hottest time of the day yet – Melbourne is expected to reach 39oC, 12oC hotter than current.  Wonder what my backyard will be then?  I expect we will hit 44-46oC locally, as has also been the case in recent weeks.

The sun is currently beating on the northern and eastern walls of the shed.

External Shed Conditions:

Ambient: 35oC

North Wall: 52oC
East Wall: 46oC
West Wall: 37oC
South Wall: 37oC
Northern PA Door: 56oC
Southern PA Door: 36oC
Roller Door: 55oC

Internal Shed Conditions:

Ambient: 31oC

North Wall: 34oC
East Wall: 39oC
West Wall: 34oC
South Wall: 35oC
Northern PA Door: 50oC !
Southern PA Door: 35oC
Roller Door: 46oC !

So what are the take-aways from this?  First, overall, the insulation is achieving some degree of block to heat transfer directly through the walls.  It could do better, but it is not the weakest spot in the shed.  I didn’t bother assessing the mezzanine area – there is a lot of heat buildup up there – probably a good 5-8oC higher, which would have been assisted if the whirlybirds hadn’t disappeared off the materials list at some stage in the process.  I’ll probably have to add a couple back on at some stage if the upper area is ever going to be useful (in summer) for anything but storage.

The eastern wall (given the time of day) is still showing the effects of the earlier morning sun, so the limit of the insulation was exceeded – it being a 39oC radiator into the shed, pushing up the ambient temp.

The weakest spot is definitely the doors – each being like having a 50oC radiant heater sitting there.  The PA door is hot and is a compromise to the boundary, but it is the roller door that is really letting the heat through.  If I ever expect to get any control over the shed conditions, the roller door issue will need to be addressed.  The PA doors can at least have insulation attached to them.  Surprisingly, the window did not seem to be a particular cause of issues – anything that was near the window and exposed to direct sun of course copped it.

Air conditioning the shed is not an option currently – the size of the unit required is a bit too expensive to think about.  I do wonder if an evaporative unit would make any difference?  Increasing insulation on the shed walls would also be an option, but only after some of the lower hanging fruit has been plucked, and the cost (and lack of ease of insulating after construction) will also be a real factor.

In the meantime, the shed is 4oC below external ambient, not exactly the 10oC I was told to expect.  And that is without the insulation compromised further with laserlight.

That may be currently workable (just) (although as the day progresses, the heat will continue to build), but I can’t do any filming out there – dripping in perspiration is not exactly the look I want on camera!

How have others solved the heat issue in their sheds?

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