The changes in technology will allow for building an ice room. Ice room meaning a cooler area for a guard house, mail box, a mobile unit and/or an ice storage unit.
A multilayered wall to form a box. The wall will have layers of vacuum and/or other insulation material combined with another layer that exchanges heat with a geo thermal source or a coolant layer that can be cooled with a Direct Current (DC) compressor. The changes in technology will allow for this to happen with or without a general purpose alternating current supply. The device with a solar panel or other renewable source of energy can run the minimal power needs of the device in conjunction with a battery. The geo thermal source will also stabilize the area not to get too cold or too hot for a general-purpose use. If there is any excess energy can be used to make ice that can be used for later use. The device will need other peripherals to make this happen like thermal sensors, wires and/or switches that would be used typically in refrigeration and/or geothermal heat exchangers.
The box or this cooling area can be used for any purpose that needs thermal heat control.