Hi all,
Is there a calculation that would allow me to determine the heating requirement, in watts, for a given enclosure size?
Here is the requirement:
A polycarbonate enclosure with a clear window front, measures 120mm x 65mm x 65mm externally. Wall thickness is about 2mm.
In the enclosure is a fisheye camera, IR Leds, WiFi and a buck converter to supply the 12v to the camera. Note: This project is still in development.
The buck converter is supplied with a nasty automotive 48v DC battery forklift supply. The buck converter claims 95% efficiency.
Total power dissipation of the circuit is 8.25w with the IR Leds on and 2.9w with them off.
The camera is mounted above the driver to monitor driver behaviour.
The forklifts work a coldstore. In summer here in Nelson NZ, the forklift can transition between -30oC, 12%RH in the freezers to +28oC, 80%RH outdoors (in summer).
In doing so, everything naturally becomes covered in condensation. When the forklift returns to the freezer that condensation, if still on the devices, will freeze.
The existing forklift mounted touch screen computers we have on the forklifts are internally heated. The surface temperature of the touchscreen sits between +25oC and +28oC.
This prevents condensation forming on the screen during normal operation.
My plan is to FET switch resistors to act as heaters inside the enclosure, maintaining an internal air temperature of about +30oC.
I will control the temperature with a simple MCU and temperature sensor.
Overall current consumption of the circuit is not a consideration. It is on a 4 tonne battery forklift with a monster battery.
So the question is:
How do I calculate the maximum power dissipation in watts required to keep the window warm enough to prevent condensation?
Or, how do I calculate the power required in watts to offset the thermal loading of -30oC and maintain a window surface temperature of between +25oC and +28oC…?
Is there even a way to calculate this, or is it just a matter of trial and error?
Thank you for reading this far, and thank you in advance for any pointers.