This test implements a few quick and dirty ideas to reduced the temperature difference between the coldest place in the refrigerated well and the warmest place. Two modifications were made:
A second ring of sealing was added to the lid. This serves two purposes. 1) Eliminating gaps observed below and between the peices of the single seal. These were permitting air circulation. 2.) Moving the seal perimeter outward. The lip of the refrigerated well was exposed to outside air and cold to the touch, indicating that it was acting as a heat exchanger with the air. Now much more of the lip is within the seal.
The lid was insulated. The lid was cold to the touch, indicating that heat was flowing in To simulate a double-pane lid, corrugated plastic was stacked on top of the existing single pane lid.
The modifications were installed at approximately 3 hours. Note that Temp IR oscillates as the lid is opened and closed, and then settles down with T3.
T3 came down about 1/2 degree vs yesterday's configuration. Ideally the value would be around 4C.
Interestingly, T3's average settling time is several hours. This is a contrast to T3's short term oscillations which occur over a time scale of minutes, and the movements of the other sensors that occur over seconds. This suggests there is not a good thermal transport mechanism to move heat from blood products lying on top to the cold well walls, where refrigeration is applied.
A small fan was added to circulate air at the top of the refrigerated well. Previous modifications remain in place: double lid seal and lid insulation.