Heating and Cooling a Resistor: Part 1

Last Wednesday, we started collecting real world data of heating and cooling in addition to the simulations.

Deliverable 1: Experimental heating data

Heating curve for 100% power for 300 seconds

C= 8.879 Ws/K

Rth=11.97 K/W

Time constant = 106 sec

 

The expected time for the system to reach .63 of its asymptote is 106 seconds. Actually, this occurred at 73 sec, showing that we were close but far from perfect in our calculations of the constants. 

Deliverable 2: Simulation of heating

Simulation of heating at 100% power for 5 min

The simulation is a much smoother curve, since it has no external factors, and has no flat spot at the start due to a delay in the heating starting and registering in the sensor. It also comes to a slightly different temperature than the real version because our constants and the power in watts were only approximated. 

Deliverable 3: Bang-bang control

Simulating bang-bang control

Simulation in red, actual results in blue for bang-bang control

We changed the target temperature to 305K because our thermistor was not calibrated and the upper limit that the heater could reach was around 320. The real data showed significantly larger fluctuations, since the real system has sensor and heating delays, but reached the desired temperature faster than the simulation, implying that maybe our constants or power value were inaccurate.