Heat exchanger 40 in this embodiment is a thermoelectric cooler capable of pumping heat from {TAIL ~ a cool side} to a hot side of {HEAD ~ the device} 
Heat exchanger 40 in this embodiment is a thermoelectric cooler capable of pumping heat from { TAIL ~ a cool side } to a hot side of { HEAD ~ the device }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD