One of my vendors on the railcar R&D project had a brake shoe force measurement device that operates by scavenging vibration with a piezo-electric device to power the force sensor, a small PIC microcontroller and an ANT transceiver. My railcars use a Timken bearing generator that charges a 12 volt deep cycle battery to run a PC104 stack with a GPS, cellphone (1x-RTT) for internet access, 802.11b with OLSR mesh network and a CAN interface to control a network of data acquisition PIC devices. Energy scavenging is a viable way to operate these devices on freight rail cars.
I was aware that these type units were in R&D. Would it be possible to operate a refrigeration unit solely by scavenging vibration?