An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve, a regenerative heat exchanger is placed inboard of the radiators.

Heat load is reduced by more than half.

An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve, as illustrated in (a), a regenerative heat exchanger is placed inboard of the radiators as shown in (b). A regenerator cold side bypass valve is used to set the return temperature.

During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system setpoint while maintaining full flow through the radiators.

By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

This work was done by Eugene K. Ungar and Richard G. Schunk of Johnson Space Center. MSC-24423-1