i've read what you guys discussed and as for the electrics, we should stay away from using programming as the control system. Programming seems like it would require alot more electronic components. I think we shoud use analog feedback as the control system. As for the accuracy of the temperature control, i dont think it needs to be very accurate. As long as the temperature gets below our required temperature, we've done our job, it should also keep the overall cost less. We need to build a refridgerator for a rural Mexican family, not the 21th century American family. So price should be a bigger concern to us than efficiency.
i've come up with a simple mock up circuit for the refridgeration portion if its using thermoelectric cooling. i can show it tomorrow.
-justin
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Interesting blogspot topic. Low total system cost is a tough challenge. (Fridge + PV + Batt)
ReplyDeleteI spoke with Matthew about the electronics and for less than $30 we can have a programmed FPGA that uses n amount of inputs (up to 44 i think). The sensitivity of the controller could be implemented within the FPGA and thus would cost us nothing. I agree that we should not try and do something crazy (like expensive sensors) but to make a refrigerator efficient, the compressor or thermoelectric has to know how long to turn on and off. I guess it comes down to what the definition of "accuracy" is and this depends on our requirements, which we have yet to receive (they were promised by tonight). My concern is with the power management. We want to conserve as much power as possible during operation. This is especially true when we are without the solar panel and relying solely on the battery.
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