Carbon dioxide refrigeration cycle

A method for cooling a target fluid, comprising:

• circulating a working fluid through a working fluid circuit with a pump;
• heating the working fluid in a heat exchanger arranged in the working fluid circuit in fluid communication with the pump, wherein the heat exchanger is configured to be in thermal communication with a waste heat source;
• cooling the working fluid with a condenser arranged in the working fluid circuit upstream from and fluidly coupled to the pump;
• extracting a portion of the working fluid discharged from the heat exchanger to be used as a motive fluid in an ejector, the ejector being fluidly coupled to the heat exchanger;
• extracting a portion of the working fluid discharged from the condenser to be used as a suction fluid in the ejector;
• expanding the suction fluid in an expansion valve to generate a cooled suction fluid, the expansion valve being fluidly coupled to the condenser;
• and
• cooling the target fluid with the cooled suction fluid in an evaporator fluidly coupled to the expansion valve.

A refrigeration cycle, comprising:

• an ejector fluidly coupled to a heat exchanger arranged in a working fluid circuit and configured to receive a motive fluid from the heat exchanger, wherein the heat exchanger is configured to transfer thermal energy from a waste heat source to a working fluid comprising carbon dioxide circulating throughout the working fluid circuit, wherein the motive fluid is a portion of the working fluid discharged from the heat exchanger;
• a condenser arranged in the working fluid circuit and fluidly coupled to a discharge of the ejector, the condenser being configured cool the working fluid in the working fluid circuit and simultaneously cool a mixed fluid discharged from the ejector;
• an expansion valve fluidly coupled to the condenser and configured to receive and expand a suction fluid to generate a cooled suction fluid, the suction fluid being a portion of the working fluid discharged from the condenser and subsequently entrained into the ejector to form part of the mixed fluid;
• an evaporator in fluid communication with the expansion valve and having a target fluid circulating therein, the evaporator being configured to transfer thermal energy from the target fluid to the suction fluid such that the target fluid is cooled and the suction fluid evaporates;
• and
• an upstream source fluidly coupled to the evaporator and providing the target fluid to the evaporator.