1. Toryalai Hart
  2. Supply chain and logistics
  3. Saturday, 05 October 2013

We think of fridge holdover time (autonomy) in the context of power shortage, whether cloudy weather in the case of solar, or power cuts for A/C systems.

While this will see functioning equipment through power shortages and keep vaccine 'safe' for a given duration (a parameter which varies immensely in function of the technology chosen) if there is an actual failure in the system, we're losing out on the opportunity to notify users of the failure so that technicians can arrive on site repair the system before temperatures go out of range.

At a larger facility, one could argue that stocks can be moved from a broken fridge to a functioning one, but many community level health facilities only have that one fridge and once it goes out range, vaccine life starts dropping much faster (function of specific antigen and ambient storage temperature).

At the moment, the majority of systems just have a power LED and perhaps an LED to show that a compressor is running. If systems had a circuit that diagnosed any failure, and in turn lit up a "Fault" light, users at sites could call for help, and technicians could arrive before the device's temperature goes out of the acceptable range. In an ideal world, fridges would also be equipped with SMS capability and technicians would be notified directly of failure with a countdown based on autonomy to indicate how long they have to get to the site before vaccines are "in peril".

In the meantime, I would be curious to hear from manufacturers, for technologies currently in the field, how a user could preemptively become aware of a failure for specific products. While such diagnostics in the absence of a global "Fault" reporting system may not cover every possible failure, perhaps such knowledge, if imparted into users, could save a lot of vaccines.

Accepted Answer Pending Moderation
We have often thought about the benefits of 'diagnostic monitoring' of refrigerators to warn of failures or mis-use including: - safe holdover remaining in case of grid failure or no-sun - alert that thermostat is failing, range excessive - temperature is more rapid than expected (door open or large load) - warning that mean temperature is drifting down (ambient change) calling for thermostat adjustment - estimated 'holdover' remaining in ice-liner, etc. Jon Colton submitted a GF Challenge proposal to study the algorithms needed to interpret temperature data - not accepted. PATH demonstrated that the existing thermostat on a compression refrigerator can be taken over by a black box with remote sensor. The box takes over the control of the compressor, monitors, transmits the data and the diagnostics Some research is needed before a spec can be written for industry. Perhaps we can start a group that debates the questions to be answered? Let's see first what Jon has to say. Best John John Lloyd Immunization Logistics Consultant [email protected] 10 chemin du Mont Blanc 01210 Ferney Voltaire France +33 674 932914
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  2. Supply chain and logistics
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