Drying a refrigerated cargo box following wash out prior to loading

1. A method for conditioning an empty cargo box of a mobile refrigerated container equipped with a refrigeration unit, the method comprising:

prior to loading cargo into the empty cargo box, performing operations to dry the cargo box by removing moisture from the cargo box, the operations comprising:

circulating air from the cargo box through an evaporator of the refrigerant unit and back to the cargo box; and

operating the refrigerant unit in alternating cycles of first heating the circulating air and then cooling the air.

2. The method as recited in claim 1 wherein operating the refrigerant unit in alternating cycles of first heating the circulating air and then cooling the air comprises:

heating the circulating air for a heating period and upon expiration of the heating period, cooling the circulating air for a cooling period; and

repeating said alternate heating and cooling cycles for a preset drying period of time.

3. The method as recited in claim 2 wherein in each heating cycle heating the circulating air for a heating period comprises heating the circulating air for a preset heating period of time.

4. The method as recited in claim 2 wherein in each cooling cycle cooling the circulating air for a cooling period comprises cooling the circulating air until the circulating air passing back to the cargo box has been cooled to a preselected temperature.

5. The method as recited in claim 2 wherein in each heating cycle heating the circulating air for a heating period comprises heating the circulating air for a preset heating period of time and in each cooling cycle cooling the circulating air for a cooling period comprises cooling the circulating air until the circulating air passing back to the cargo box has been cooled to a preselected temperature.

6. The method as recited in claim 5 further comprising:

at the completion of each cooling cycle determining whether the elapsed time from commencement of the drying process exceeds the preset drying period of time; and

if the elapsed time from commencement of the drying process exceeds the preset drying period of time, terminating the drying process.

7. The method as recited in claim 6 further comprising upon termination of the drying process operating the refrigeration unit in a defrost cycle for defrosting the evaporator.

8. A method for conditioning an empty cargo box of a mobile refrigerated container equipped with a refrigeration unit, the method comprising:

prior to loading cargo into the empty cargo box, performing operations comprising:

operating a fan operatively associated with an evaporator of the refrigeration unit for circulating air from the cargo box through the evaporator and back to the cargo box;

determining whether a sensed ambient temperature external to the cargo box is less than the freezing point of water;

when the sensed ambient temperature is less than the freezing point of water, operating the refrigeration unit in a heating cycle and heating the circulating air passing through the evaporator for a preset heating period of time;

when the sensed ambient temperature is not less than the freezing point of water or upon termination of the heating cycle, setting a setpoint control air temperature and operating the refrigeration unit in a cooling cycle for cooling the circulating air passing through the evaporator;

sensing a temperature of the circulating air having traversed the evaporator and being supplied back to the cargo box;

comparing the sensed supply air temperature to the setpoint control air temperature; and

when the sensed supply air temperature equals the setpoint control air temperature, then performing:

determining an elapsed time from initiating operation of the refrigeration unit in the remove moisture mode;

if the elapsed time is less than a preset drying period of time, repeating the heating cycle and cooling cycle sequence; and

if the elapsed time equals or exceeds the preset drying period of time, terminating operation of the refrigeration unit in the remove moisture mode.

9. The method of claim 1 , further comprising:

washing out the cargo box prior to the loading cargo into the cargo box.

10. The method of claim 8 , further comprising:

washing out the cargo box prior to the loading cargo into the cargo box.

11. The method of claim 1 , further comprising:

selecting a remove moisture option from a menu of a display associated with a controller of the refrigeration unit to initiate the circulating and the operating.