Thermo King Corporation

Steven Bruce Helgeson

Jay L Hanson

Stanley Oscar Hoium

A transport temperature control unit and methods of defrosting an evaporator coil of a transport temperature control unit. The transport temperature control unit includes an evaporator coil, an ambient air temperature sensor for sensing an ambient air temperature, a return air temperature sensor for sensing a return air temperature, a discharge air temperature sensor for sensing a discharge air temperature, an evaporator coil temperature sensor for sensing an evaporator coil temperature, and a controller. The controller initiates a defrost cycle when a large temperature differential occurs over the evaporator coil.

Transport temperature control unit and methods of defrosting an evaporator coil of the same

A method of controlling the operation of an electronic throttling valve in a temperature control unit having first and second pressure measurement devices. The method includes determining whether the first pressure measurement device is functioning, determining whether the second pressure measurement device is functioning, controlling the electronic throttling valve using data measured by both the first and second pressure measurement devices when both the first and second pressure measurement devices functioning, controlling the electronic throttling valve using data measured by only one of the first and second pressure measurement devices when the other of the first and second pressure measurement devices is determined to be non-functional, and controlling the electronic throttling valve using temperature data measured by the temperature control unit when both the first and second pressure measurement devices are determined to be non-functional.

Electronic throttling valve diagnosis and preventative shutdown control

A method for continuously operating a multi-temp refrigeration system at a high compressor speed is provided. Such refrigeration systems include a compressor for compressing a refrigerant at a high speed and a low speed, a condenser coil for receiving and liquefying gaseous refrigerant, first and second evaporator coils for heating or cooling two different conditioned spaces, a hot gas valve for admitting hot gaseous refrigerant to one of the evaporator coils in order to heat its associated conditioned space, and a condenser inlet valve for rerouting a flow of hot gaseous refrigerant from the condenser coil to the evaporator coils. In the method of the invention, the evaporator hot gas valve is first opened to heat one of the conditioned spaces, and the condenser inlet valve is then closed to direct a flow of hot gaseous refrigerant to the opened hot gas valve. Instead of continuously maintaining the condenser inlet valve in a closed position, this valve is periodically opened and reclosed in the method of the invention to maintain a refrigerant head pressure in the system below a level associated with a system shut-down condition. The method obviates the need for operating a multi-temp refrigeration system at a low compressor speed when the system is used to simultaneously heat and cool different conditioned spaces.

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Lakeville, MN, United States of America

Steven Bruce Helgeson