Intro:

One of the projects I am planning (the design and construction of a heat recovery and ventilation system) requires a membrane that efficiently transfers heat from one body of air to another.

I am planning to use regular household aluminium foil for this. It has a lot of things in its favour including

Note: I have recently decided that the heat recovery unit will probably use copper foil instead since copper has roughly double the conductivity of aluminium and I can get it in foil only 50% thicker than kitchen foil.

• It’s cheap
• Readily available
• Aluminium is a very good conductor
• Cheap foil is very thin (usually a problem when you want to use it to wrap something!) so have very little mass, which should allow freer flow of heat from one side to the other

Aim:

To determine if the reflective quality of aluminium foil (which makes it so effective as insulation in buildings and “space blankets”) decrease it’s performance in this application

Hypothesis:

I expect that since the main mechanism of heat transfer in the heat exchanger is conduction, that the reflective nature of the foil will make little difference to overall performance

Equipment:

• Aluminium kitchen foil
• Matt black automotive primer
• Cardboard
• Tape
• Infrared thermometer
• A cold window

Procedure:

1. Take two pieces of foil, each approximately fourth centimeters meter long, paint one black on both sides, leave the other unpainted
2. Using cardboard, make a support frame that will hold the foil by the edges, side by side, approximately 20mm away from the window
3. Tape both pieces of foil to the frame – ensure that the foils don’t touch to prevent any heat conduction between the foil sheet
4. Tape the cardboard frame to the cold window
5. Measure the temperature of each sheet of foil with the infrared thermometer

Using a window is ideal as it will simulate the actual indoor/outdoor temperature differences that will be found in the heat recovery ventilator.  Performing the experiment at night, or on a cloudy day would be ideal so that sunlight can’t heat the foil and skew the results.

Safety/risks:

• Use spray paint in a ventilated area

Discussion/observations:

TBA

Conclusions:

TBA