Abstract: The present invention relates to systems and methods for controlling head pressure in a vapor compression system, e.g. in a precision air conditioning system. One embodiment of the invention provides a method for regulating working fluid flow in a vapor compression system including a compressor. The method includes: providing a controller; receiving signals at the controller representative of a monitored discharge pressure in a discharge line of the compressor; and using the controller to provide a control signal to an actuator that controls a flow control valve that, in turn, controls working fluid flow into the system, the control signal being responsive at least in part to a difference between a set point pressure and the monitored discharge pressure.

Abstract: An access control system prevents a mobile container from being compromised/opened during transit, through the use of a programmable electronic lock, which can be unlocked only by means of an enabled electronic key that has been programmed with geographical location data representative of the destination site of the container. When the mobile container arrives at its destination, the key is coupled with a comparator, which compares the geographic location information in the key with real time geographic location information from a geographic location detection unit associated with the mobile container. In response to a match, the comparator enables the key for a prescribed period of time. The key may then be inserted into the programmable electronic lock, which reads the key to determine whether it has been enabled. If the key is enabled, the lock can be unlocked, to provide access to the container.

Abstract: An access control system prevents a mobile container from being compromised/opened during transit, through the use of a programmable electronic lock, which can be unlocked only by means of an enabled electronic key that has been programmed with geographical location data representative of the destination site of the container. When the mobile container arrives at its destination, the key is coupled with a comparator, which compares the geographic location information in the key with real time geographic location information from a geographic location detection unit associated with the mobile container. In response to a match, the comparator enables the key for a prescribed period of time. The key may then be inserted into the programmable electronic lock, which reads the key to determine whether it has been enabled. If the key is enabled, the lock can be unlocked, to provide access to the container.