Cryogenic temperature control apparatus and method

A method of temperature control in a cryogenic temperature control apparatus comprising:

• providing a heat exchanger in thermal communication with an air-conditioned space, the heat exchanger including an air inlet and an evaporator coil having an outlet;
• providing a first temperature sensor operatively coupled to a controller, the first temperature sensor measuring the temperature in the outlet and sending the temperature in the outlet to the controller;
• providing a second temperature sensor operatively coupled to the controller, the second temperature sensor measuring the temperature in the air inlet, and sending the temperature in the air inlet to the controller;
• providing a first plurality of temperature control values and a second plurality of temperature control values;
• altering the flow of cryogen from a storage tank to the evaporator coil each time the temperature in the outlet passes one of the first plurality of temperature control values;
• and
• altering the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the air inlet passes one of the second plurality of temperature control values;
• wherein the heat exchanger includes a heating element, the method further comprising:
• providing a third plurality of temperature control values and a fourth plurality of temperature control values;
• discontinuing the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the outlet passes one of the third plurality of temperature control values;
• discontinuing the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the air inlet passes one of the fourth plurality of temperature control values;
• heating air in the heat exchanger with the heating element each time the temperature in the outlet passes one of the third plurality of temperature control values;
• and
• heating air in the heat exchanger with the heating element each time the temperature in the air inlet passes one of the fourth plurality of temperature control values.

A method of temperature control in a cryogenic temperature control apparatus comprising:

• providing a heat exchanger in thermal communication with an air-conditioned space, the heat exchanger including an air inlet and an evaporator coil having an outlet;
• providing a first temperature sensor operatively coupled to a controller, the first temperature sensor measuring the temperature in the outlet and sending the temperature in the outlet to the controller;
• providing a second temperature sensor operatively coupled to the controller, the second temperature sensor measuring the temperature in the air inlet, and sending the temperature in the air inlet to the controller;
• providing a first plurality of temperature control values and a second plurality of temperature control values;
• altering the flow of cryogen from a storage tank to the evaporator coil each time the temperature in the outlet passes one of the first plurality of temperature control values;
• and
• altering the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the air inlet passes one of the second plurality of temperature control values;
• providing a first cooling mode corresponding to a first flow rate of cryogen from the storage tank to the evaporator coil;
• and
• providing a second cooling mode corresponding to a second flow rate of cryogen from the storage tank to the evaporator coil;
• and wherein altering the flow of cryogen from the storage tank to the evaporator coil includes switching between the first cooling mode and the second cooling mode.

A method of controlling a temperature of an air-conditioned space with a cryogenic temperature control apparatus, the cryogenic temperature control apparatus including a storage tank housing cryogen and a heat exchanger in thermal communication with the air-conditioned space, the heat exchanger including an evaporator coil, the evaporator coil in fluid communication with the storage tank and having an outlet, the method comprising:

• providing a temperature sensor operatively coupled to a controller, the temperature sensor measuring an outlet temperature in the outlet and transmitting the outlet temperature the controller;
• providing a first plurality of temperature control values
• providing a first valve positioned between the storage tank and the evaporator coil, the first valve being moveable between a first open position and a first closed position;
• providing a second valve positioned between the storage tank and the evaporator coil, the second valve being moveable between a second open position and a second closed position, a first volume of cryogen being moveable between the storage tank and the evaporator coil when the first valve is in the first open position and the second valve is in the second open position, a second volume of cryogen being moveable between the storage tank and the evaporator coil when the first valve is in the first open position and the second valve is in the second closed position;
• and
• moving the first valve from the first open position to the first closed position each time the temperature in the outlet passes one of the first plurality of temperature control values.

A method of temperature control in a cryogenic temperature control apparatus, the temperature control apparatus including a storage tank housing a cryogen and a heat exchanger in thermal communication with an air-conditioned space, the heat exchanger including an air inlet and an evaporator coil in fluid communication with the storage tank, the evaporator coil having an outlet, the method comprising:

• providing a first temperature sensor being operatively coupled to a controller, the first temperature sensor measuring the temperature in the outlet and sending the temperature in the outlet to the controller;
• providing a second temperature sensor being operatively coupled to the controller, the second temperature sensor measuring the temperature in the air inlet, and sending the temperature in the air inlet to the controller;
• providing a first plurality of temperature control values and a second plurality of temperature control values;
• providing a first mass flow rate of cryogen from the storage tank through the evaporator coil;
• providing a second mass flow rate of cryogen from the storage tank through the evaporator coil;
• altering the flow of cryogen from the first mass flow rate to the second mass flow rate each time the temperature in the outlet passes one of the first plurality of temperature control values;
• altering the flow of cryogen from the first mass flow rate to the second mass flow rate each time the temperature in the air inlet passes one of the second plurality of temperature control values, wherein the heat exchanger includes a heating element;
• providing a third plurality of temperature control values and a fourth plurality of temperature control values;
• discontinuing the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the outlet passes one of the third plurality of temperature control values;
• discontinuing the flow of cryogen from the storage tank to the evaporator coil each time the temperature in the air inlet passes one of the fourth plurality of temperature control values;
• heating air in the heat exchanger with the heating element each time the temperature in the outlet passes one of the third plurality of temperature control values;
• and
• heating air in the heat exchanger with the heating element each time the temperature in the air inlet passes one of the fourth plurality of temperature control values.

A method of temperature control in a cryogenic temperature control apparatus, the cryogenic temperature control apparatus including an evaporator coil having an outlet and extending through a heat exchanger, the heat exchanger having an air inlet in thermal communication with an air-conditioned space, the method comprising:

• providing a first mode of operation corresponding to a first mass flow rate of cryogen through the evaporator coil;
• providing a second mode of operation corresponding to a second mass flow rate of cryogen through the evaporator coil;
• providing a first temperature sensor operatively coupled to a controller which uses ladder logic, the first temperature sensor measuring the temperature in the air inlet and sending the temperature in the air inlet to the controller;
• providing a second temperature sensor operatively coupled to the controller, the second temperature sensor measuring the temperature in the outlet and sending the temperature in the outlet to the controller;
• providing a first plurality of temperature control values and a second plurality of temperature control values;
• shifting between the first mode of operation and the second mode of operation each time the temperature in the outlet passes one of the first control values;
• and
• shifting between the first mode of operation and the second mode of operation each time the temperature in the air inlet passes one of the second control values.