I would like some help to evaluate the electrical feasibility of a system to heat 35 gram of thermoplastic material (for active stiffness control) in 50 ms, by about 100 degrees Celsius.
The material will be for example a thermoplastic polymer such as poly carbonate, or a composite. The idea is to have some sort of resistive wires integrated in the material for the heating process, similar as done in [1]. But please do not worry about the material part to much.
From a rough calculation i get that the required energy is:
1200 [J/kg°C]*0.035 [kg]*100[°C]=4000[J]
to heat it in 50 ms, the power required would be approximately:
4000[J]/0.050[s]=80 000 W or 80kW.
At this point i would like to know if this is roughly feasible or not from an power and current point of view with a battery set or supper capacitors of a "typical" electric car? What type of Power Draws for short peaks are feasible with capacitors, and batteries which are typically available in electric cars?
What is the approximate range? Do i need to go down a factor of 10, or can i go up a factor of 10?
[1] Tridech, Charnwit, et al. "High performance composites with active stiffness control." ACS applied materials & interfaces 5.18 (2013): 9111-9119.
Best Answer
3.5 kJ is something a capacitor bank can cough up in a short time. For example, that could be 48 V on about 3 F. You'd have to make sure the capacitors can handle the high current. Multiple capacitors in parallel, which is what it will take to get to 3 F anyway, helps with this.
However, there is going to be a lot of loss delivering that energy to a load, especially since it isn't "conductive". Its not clear whether you mean it's not electrically or not thermally conductive, but either way, it makes this problem difficult. If you do this electrically, you will need to store several times the energy ultimately delivered to the object.
Heating the object chemically might be easier. For example, a carefully calibrated layer of black powder should be able to deliver the energy in the short time you specify. There are probably much better chemical reactants than black powder. I'm just using that as a example.