Bimodal cooling system

A method of cooling a heat load, the method comprising:

• directing a cooling fluid through a two-phase pumped loop (TPPL) in a TPPL mode due to a TPPL check valve being open and a compressor check valve being closed, the two-phase pumped loop including
• a receiver,
• a heat load downstream from the receiver,
• a mixer downstream from the heat load and upstream of the receiver,
• the TPPL check valve downstream from the heat load, and
• a heat exchanger downstream from the TPPL check valve and upstream from the receiver;
• directing the cooling fluid through a vapor cycle system (VCS) loop in VCS mode due to the TPPL check valve being closed and the compressor check valve being open, the vapor cycle system loop including
• the receiver,
• a compressor downstream from a vapor outlet of the receiver,
• the compressor check valve downstream from the compressor and upstream of the heat exchanger,
• the heat exchanger, and
• the mixer downstream from the heat exchanger and upstream from receiver, an output of the heat load in fluid communication with a first inlet of the mixer and an output of the heat exchanger in fluid communication with a second inlet of the mixer,
• wherein the heat load, which is in the TPPL, is in the VCS loop downstream from a liquid outlet of the receiver;
• and
• closing the TPPL check valve if a discharge pressure of the compressor is higher than a pressure of the two-phase pumped loop upstream of the TPPL check valve when the cooling capacity of the TPPL is insufficient to cool the heat load.

A cooling system comprising:

• a two-phase pumped loop (TPPL), the two-phase pumped loop including
• a receiver,
• a pump downstream from the receiver,
• a heat load downstream from the pump,
• a TPPL tee downstream from the heat load, the TPPL tee comprising a T-shaped separator to separate a liquid portion of a cooling fluid from a vapor portion of the cooling fluid through gravity,
• a TPPL check valve downstream from the TPPL tee, and
• a heat exchanger downstream from the TPPL check valve and upstream from the receiver;
• and
• a vapor cycle system (VCS) loop, the vapor cycle system loop including
• the receiver,
• a compressor downstream from a vapor outlet of the receiver,
• a compressor check valve downstream from the compressor and upstream of the heat exchanger, and
• the heat exchanger,
• wherein the heat load, which is in the TPPL, is in the VCS loop downstream from a liquid outlet of the receiver,
• wherein the two-phase pumped loop is configured to operate in a TPPL mode in which the cooling fluid flows through the two-phase pumped loop due to the TPPL check valve being open and the compressor check valve being closed, and wherein the vapor cycle system loop is configured to operate in a VCS mode in which the cooling fluid flows through the vapor cycle system loop due to the TPPL check valve being closed and the compressor check valve being open,
• wherein the TPPL check valve is configured to close if, in response to the compressor being turned on, a pressure at an outlet of the compressor is higher than a pressure of the two-phase pumped loop upstream of the TPPL check valve,
• wherein the compressor check valve is configured to close if, in response to the compressor being turned off, a pressure at an inlet of the heat exchanger is higher than a pressure at an outlet of the compressor.