Coolant-buffered, vapor-compression refrigeration with thermal storage and compressor cycling

A cooled electronic system comprising:

• an electronic rack comprising an electronic component to be cooled;
• and
• an apparatus for facilitating cooling of the electronic component, the apparatus comprising:
• a liquid-cooled cold plate, the liquid-cooled cold plate being in thermal communication with the electronic component via a thermal conduction path from the electronic component to the liquid-cooled cold plate;
• a coolant loop coupled in fluid communication with the liquid-cooled cold plate to facilitate the flow of coolant therethrough;
• a thermal buffer unit coupled in fluid communication with the coolant loop upstream of the liquid-cooled cold plate, and disposed separate from the liquid-cooled cold plate, wherein coolant within the coolant loop is capable of flowing through the thermal buffer unit;
• a coolant-to-refrigerant heat exchanger coupled in fluid communication with the liquid-cooled cold plate via the coolant loop to receive coolant therefrom and provide coolant thereto the thermal buffer unit being disposed between the coolant-to-refrigerant heat exchanger and the liquid-cooled cold plate;
• a vapor-compression refrigeration loop coupled in fluid communication with the coolant-to-refrigerant heat exchanger, the coolant-to-refrigerant heat exchanger cooling coolant passing therethrough from the coolant loop by dissipating heat from the coolant passing therethrough to refrigerant passing therethrough from the vapor-compression refrigeration loop;
• a compressor coupled in fluid communication with the vapor-compression refrigeration loop, wherein in a first state the compressor is maintained ON responsive to heat load of the electronic component exceeding a heat load threshold, and in a second state is cycled ON and OFF responsive to heat load of the electronic component being below the heat load threshold, the thermal buffer unit coupled in fluid communication with the coolant loop dampening in the second state swings in temperature of coolant within the coolant loop during cycling ON and OFF of the compressor in fluid communication with the vapor-compression refrigeration loop;
• a bypass line coupled to a coolant loop line in parallel, with the thermal buffer unit;
• a controllable bypass valve in fluid communication with the bypass line;
• and
• a controller configured to automatically control the controllable bypass valve to provide selective coolant bypass of the thermal buffer unit and thereby control an amount of coolant in the coolant loop passing through the thermal buffer unit, to facilitate maintaining temperature of coolant within the coolant loop downstream of the thermal buffer unit within a defined temperature range, the controller controlling the controllable bypass valve to, in part, control coolant flow through the bypass line, and thus through the thermal buffer unit, and in so doing, control a rate of thermal energy release from the thermal buffer unit.

A method of facilitating cooling of an electronic component, the method comprising:

• coupling in thermal communication a liquid-cooled cold plate to the electronic component, the liquid-cooled cold plate being in thermal communication with the electronic component via a thermal conduction path from the electronic component to the liquid-cooled cold plate;
• coupling a coolant loop in fluid communication with the liquid-cooled cold plate to facilitate the flow of coolant therethrough;
• coupling a thermal buffer unit in fluid communication with the coolant loop upstream of the liquid-cooled cold plate, and disposed separate from the liquid-cooled cold plate, wherein coolant within the coolant loop is capable of flowing through the thermal buffer unit;
• providing a coolant-to-refrigerant heat exchanger coupled in fluid communication with the liquid-cooled cold plate via the coolant loop to receive coolant therefrom and provide coolant thereto, the thermal buffer unit being disposed between the coolant-to-refrigerant heat exchanger and the liquid-cooled cold plate;
• providing a vapor-compression refrigeration loop coupled in fluid communication with the coolant-to-refrigerant heat exchanger, the coolant-to-refrigerant heat exchanger cooling the coolant passing therethrough from the coolant loop by dissipating heat from the coolant passing therethrough to refrigerant passing therethrough from the vapor-compression refrigeration loop;
• providing a compressor coupled in fluid communication with the vapor-compression refrigeration loop;
• providing a controller controlling operation of the compressor, the controller maintaining the compressor ON in a first state responsive to heat load of the electronic component exceeding a heat load threshold, and cycling the compressor ON and OFF in a second state responsive to heat load of the electronic component being below the heat load threshold, the thermal buffer unit coupled in fluid communication with the coolant loop dampening in the second state swings in temperature of coolant within the coolant loop during cycling ON and OFF of the compressor in fluid communication with the vapor-compression refrigeration loop;
• providing a bypass line coupled to a coolant loop line in parallel, with the thermal buffer unit;
• providing a controllable bypass valve in fluid communication with the bypass line;
• and
• providing a controller configured to automatically control the controllable bypass valve to provide selective coolant bypass of the thermal buffer unit and thereby control an amount of coolant in the coolant loop passing through the thermal buffer unit, to facilitate maintaining temperature of coolant within the coolant loop downstream of the thermal buffer unit within a defined temperature range, the controller controlling the controllable bypass valve to, in part, control coolant flow through the bypass line, and thus through the thermal buffer unit, and in so doing, control a rate of thermal energy release from the thermal buffer unit.