US Patent 7703835 Secondary door and temperature control system and method

An inner or secondary door and temperature control system for use on a vehicle or trailer having a storage compartment and a first or primary door associated with a first entry or entryway into the storage compartment. The secondary door provides a moveable barrier or door that is situated in operative relationship to the first entry or entryway associated with the first door in order to prevent thermal loss from the storage compartment area during deliveries or at times when the first door is open.