AUTO-DEFROST SYSTEM IN ACTIVELY COOLED TOTE

1 . A method of operating an actively cooled container, comprising:

determining to initiate a defrost cycle for the actively cooled container;

deactivating a cooling system of the actively cooled container;

activating a defrost heater of the actively cooled container;

determining to deactivate the defrost heater of the actively cooled container;

setting the defrost heater to maintain a temperature of a thermal accept system at a threshold;

waiting a set duration of time to allow for melted frost to drip into a collection tray; and

activating the cooling system of the actively cooled container.

2 . The method of claim 1 further comprising:

deactivating one or more fans of the actively cooled container.

3 . The method of claim 1 further comprising, after waiting the set duration of time:

activating one or more fans of the actively cooled container.

4 . The method of claim 3 wherein activating the one or more fans comprises:

in response to determining that the temperature of the thermal accept system is at or below a set threshold temperature, activating one or more fans of the thermal accept system.

5 . The method of claim 4 wherein the set threshold temperature is zero Celsius.

6 . The method of claim 1 wherein determining to deactivate the defrost heater comprises one or more of:

determining that the defrost heater has been activated for a predetermined amount of time;

deactivating that a temperature of a thermal accept system crosses above a set threshold.

7 . The method of claim 1 wherein determining to initiate a defrost cycle comprises one or more of:

reaching an elapsed time since prior defrost;

determining that a difference between an accept temperature and a chamber temperature exceeds a specified value;

determining that a lid open duration and subsequent full-power operation ratio exceeds a specified value;

determining a relative humidity of the actively cooled container; and

determining a mass of frost currently on the heat exchanger.

8 . The method of claim 1 further comprising:

activating an alarm indicating that frost may have built up.

9 . The method of claim 1 further comprising:

determining that a threshold number of defrost cycles have been performed.

10 . The method of claim 1 further comprising:

ensuring that the temperature of the actively cooled container does not rise above an allowable limit.

11 . An actively cooled container, comprising:

a cooling system;

one or more fans;

a collection tray; and

a controller; the controller operable to:

determine to initiate a defrost cycle for the actively cooled container;

deactivate a cooling system of the actively cooled container;

activate a defrost heater of the actively cooled container;

determine to deactivate the defrost heater of the actively cooled container;

set the defrost heater to maintain a temperature of a thermal accept system at a threshold;

wait a set duration of time to allow for melted frost to drip into the collection tray; and

activate the cooling system of the actively cooled container.

12 . The method of claim 11 wherein the controller is further operable to:

deactivate one or more fans of the actively cooled container.

13 . The method of claim 11 wherein the controller is further operable to, after waiting the set duration of time:

activate one or more fans of the actively cooled container.

14 . The method of claim 13 wherein being operable to activate the one or more fans comprises being operable to:

in response to determining that the temperature of the thermal accept system is at or below a set threshold temperature, activate one or more fans of the thermal accept system.

15 . The method of claim 14 wherein the set threshold temperature is zero Celsius.

16 . The method of claim 11 wherein being operable to determine to deactivate the defrost heater comprises being operable to perform one or more of:

determine that the defrost heater has been activated for a predetermined amount of time;

deactivate that a temperature of a thermal accept system crosses above a set threshold.

17 . The method of claim 11 wherein being operable to determine to initiate a defrost cycle comprises being operable to perform one or more of:

reach an elapsed time since prior defrost;

determine that a difference between an accept temperature and a chamber temperature exceeds a specified value;

determine that a lid open duration and subsequent full-power operation ratio exceeds a specified value;

determine a relative humidity of the actively cooled container; and

determine a mass of frost currently on the heat exchanger.

18 . The method of claim 11 wherein the controller is further operable to:

activate an alarm indicating that frost may have built up.

19 . The method of claim 11 wherein the controller is further operable to:

determine that a threshold number of defrost cycles have been performed.

20 . The method of claim 11 wherein the controller is further operable to:

ensure that the temperature of the actively cooled container does not rise above an allowable limit.