Cold loop Ā· The next improvement

Keep the heat
inside the loop.

The turbine outlet is still warm enough to heat the gas leaving the compressor. A counterflow recuperator transfers that heat internally, reducing the load on both the warm heat source and the cold bath.

At the selected 85% effectiveness target, with an extra 1 kPa pressure loss on each nitrogen side, cooling-nitrogen use falls from 1.68 to 0.48 kg per 20-second duty.

Warm-air bypass is part of the solution. Processing only the air needed for the reduced heat load raises steady net output to 18.2 kJ. The remaining 19.8 kg of the prepared 30 kg air stream stays unchanged.

Include the control that loses output.

With the same full warm-air flow, the added pressure losses lower net output to 12.5 kJ. Heat recovery alone does not produce the 18.2 kJ result; reducing unnecessary blower work does.

The recuperator requires about 582 W/K conductance at the selected point. Its effectiveness, pressure loss, mass and startup remain hardware targets. No vehicle credit is added.

Heat recovery and its pressure cost.

Net steady DC18.2kJ / 20 s
Coolant boiloff0.48kg nitrogen
Active warm air10.2kg of 30 kg available
Recuperator required UA582W/K

Same prepared resources available. Extra core losses and retained bypass air are counted. Startup and installed mass are unqualified.

All 40 recuperator states and controls ā†—Calculation source ā†—