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R744 / CO₂ · ADVANCED TRANSCRITICAL CYCLE
Flash Tank & Parallel Compression
Extend the four-state R744 transcritical model into a flash-receiver architecture: split receiver liquid and flash vapor, compress the flash gas in a parallel compressor, mix both discharge streams and quantify COP, mass flow and compressor-duty effects.
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Cycle model
- Main suction starts from the entered evaporating saturation temperature and superheat.
- Main compression raises evaporator vapor directly to the entered transcritical high-side pressure.
- The gas-cooler outlet throttles isenthalpically to the entered flash-receiver pressure.
- The receiver separates equilibrium saturated vapor and liquid. Vapor goes to the parallel compressor; liquid supplies the evaporator after a second throttling step.
- The parallel compressor raises flash vapor to the same high-side pressure.
- Main and parallel discharge streams mix by mass/enthalpy balance before the gas cooler.
OEM compressor envelope review →Simple R744 transcritical cycle →R744 ejector architecture →R744 heat recovery →Compare R744 architectures →Advanced cycle comparison →Advanced P-h workspace →Subcritical Cycle Analyzer →Flash economizer / vapor injection →Two-stage compression →
WHEN TO USE THIS TOOL
Useful during reference & conversion work.
- Resolve unit-system differences quickly across calculations, drawings, schedules and vendor data.
- Look up common formulas, constants and engineering reminders without leaving the HVACR workspace.
- Reduce repeated manual conversion work while keeping the final engineering review with the user.
Frequently asked questions
What architecture is modeled?
A transcritical R744 system with a flash receiver. Receiver liquid feeds the evaporator; saturated flash vapor is compressed separately by a parallel compressor and mixes with the main-compressor discharge before the gas cooler.
Does HVACR Studio choose receiver pressure?
No. Receiver pressure is an explicit engineering input. The tool does not optimize receiver pressure, high-side pressure or controller setpoints.
What does the flash-gas fraction mean?
It is the equilibrium vapor mass fraction produced when the gas-cooler outlet is throttled to the entered receiver pressure. The model then converts that fraction into parallel-compressor mass flow relative to evaporator flow.
Does the COP comparison prove field energy savings?
No. It compares two theoretical refrigerant cycles at the same entered boundary conditions. Compressor maps, controls, pressure drops, heat exchangers, fan power and other equipment losses affect actual performance.