So I have mostly finished (finally) one of the actuated window shutters.
[video]<iframe width="854" height="480" src="https://www.youtube.com/embed/2AyCKP4motE" frameborder="0" allowfullscreen></iframe>[/video]
This was likely not the optimal way to do this but space, cost and other factors limited my options.
The coolroom panels I used are 50mm thick @ R1.3. Basically a galvanized metal, foam filled sandwich - they are not a ‘sustainable’ product. Whilst I could have increased the thickness, the returns would have been vanishing. Windows + Panels = R1.8 which means my windows loose about 170Watts on a cold day – which is already less than what I loose from the walls, floor and roof individually. Doubling the panel thickness brings this down to 100 Watts, not worth it (FYI was 600 Watts before panels). Was exactly $1000 for ~ 15m^2 of panels including C channel to connect the edges and delivery.
The panels are riveted together at about 300mm centers and the C channel adds a huge amount of rigidity. There is also a length of tube steel (galvanized) on the front and back for further rigidity ($5 pm). They are very rigid lengthwise but need at least the C channel along the edges or they will break apart at the point they connect to each other. The hinges are standard door hinges (100x75mm) attached to the timber with batten screws and bolted on to the panels. I have fixed two small wooden protrusions to the eaves to reduce the cantilevering in high wind events.
The muscle is a few 36V 3A 550kg satellite actuators which are $100 each. Now the panels only weigh 12kg/m^2 however as the actuators extend to only 600mm, there is a huge amount of applied torque (Force-Load x Distance-Load = Force-Applied x Distance-Applied). At a horizontal position, the largest shutter requires 3500 Newton.Meters or about 350kg worth of “push” to open (for an 80kg panel). The actuators can easily handle this (I have 2 on the big one) however this places much more strain on the bolts and screws. Luckily for me an M12 bolt can take a shear force of about 2000 kg. Even tiny M4 bolts can take 200kg.
The system is controlled via an Arduino Uno microcontroller ($40 with accessories), a relay board and two power supplies (12V and 36V). Unfortunately 36V power supplies are hard to find and expensive ($70) so best stick to 12V or 24V if possible. The shutters are programmed to open at 8AM ish and close at 5PM ish and I’ll change it once or twice a year to coincide with sunrise/sunset. I also brought a $10 transmitter receiver from ebay to manually open or close them if the need arises. A future step will be to hook a tiny solar panel to the arduino which will average insolation readings and open the shutters when its sunny, close when cloudy. The electronics and the programming were pretty easy, time consuming but interesting to learn. There is plenty of excellent information on the web.
Might post some more photos later. For now enjoy the boring video.
Panels $1000. Actuators $500. Timber $300. Misc $400. Time $Too much. Total $2200 ish
http://masda.com.au/home/60-eps-panel-size-2700mm-x-950mm-x-50mm-off-white-z-lock.html
http://www.sciteq.com.au/shop/24inch-heavy-duty-actuator-qarl-3624/
Posted Monday 20 Jun 2016 @ 10:05:53 am from IP
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