❄️ Transcritical CO2 Refrigeration (R744)

Model commercial transcritical CO2 (R744) refrigeration: optimal gas cooler high-side pressure, cooling COP, compressor power demand, and heat pump heating capacity.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

Thermodynamics

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⚡ Solves 25

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📅 Released Jun 2026

⏱️ Latency < 1 ms

❄️ Transcritical R744 CO2 Refrigeration & Gas Cooler Loop

Real-time visual simulation: Supercritical gas cooling above critical point (73.8 bar) with optimal high pressure control

📝 Configuration & Presets

🛒 Supermarket MT Pack (-8°C) 🧊 Commercial LT Freezer (-32°C) ♨️ EcoCute Water Heat Pump (+5°C) 🏭 Industrial Cold Store (-15°C)

🌡️ Evaporation & Gas Cooler Temperatures

Evaporating Temp T_e [°C]:

Gas Cooler Exit Temp T_gc,out [°C]:

⚡ High-Side Pressure & Flow

High Pressure P_high [bar]: Supercritical: P > 73.8 bar

R744 Mass Flow ṁ [kg/s]:

⚙️ Compressor & Suction Properties

Compressor Isentropic Eff. η_is:

Suction Superheat ΔT_sh [K]:

Transcritical CO2 (R744) Formulation:
• Optimal High Pressure: P_opt ≈ 2.6 · T_gc,out + 7.5 [bar]
• Cooling Capacity: Q̇_cool = ṁ · (h₁ − h₄) [kW]
• Compressor Power: Ẇ_elec = ṁ · (h₂ − h₁) [kW]
• Cooling COP: COP_cool = Q̇_cool / Ẇ_elec

📊 R744 Cycle Results

📊 Output Summary
💾 Fortran Source

Refrigeration Cooling Capacity (Q̇_cool)

129.47 kW

Cooling COP: 1.917 | Heating COP: 2.917

P_opt = 75.0 bar

Compressor Electrical Power 67.55 kW η_is = 75 %

Gas Cooler Heat Rejection 197.03 kW Heat recovery potential

Evaporator Saturation Pressure 35.32 bar T_e = 5 °C

Compressor Discharge Temp 109.1 °C Superheated discharge

📈 Cooling COP vs High-Side Pressure P_high (bar) — Optimal Peak

📉 Cooling Capacity Q_cool (kW) vs Gas Cooler Outlet Temp (°C)

=================================================================
 THERMOFLUIDCALC — TRANSCRITICAL CO2 (R744) REFRIGERATION REPORT
=================================================================
Case Title                 : EcoCute Domestic High-Temperature Hot Water Heat Pump
Thermodynamic State Points : Te = 5.0 C (Pe = 35.32 bar), Tgc_out = 25.0 C, P_high = 90.00 bar
Optimum Control Pressure   : P_opt = 75.00 bar (High-side pressure optimization)
R744 Mass Flow & Eff.      : m_dot = 0.50 kg/s, eta_is = 0.75, superheat = 4.0 K
-----------------------------------------------------------------
COOLING CAPACITY (Q_cool)  : 129.47 kW
COMPRESSOR ELECTRICAL POWER: 67.55 kW
REFRIGERATION COOLING COP  : 1.9166
HEAT PUMP HEATING COP      : 2.9166
Gas Cooler Heat Rejection  : 197.03 kW
Compressor Discharge Temp  : 109.08 deg C
=================================================================

📘 Calculation Methodology & Transcritical CO2 Standards

Optimal High-Side Pressure

Unlike subcritical cycles where condensing pressure is fixed by temperature, supercritical $CO_2$ gas cooling exhibits a distinct maximum $COP$ at an optimum pressure $P_{opt} \approx 2.6 T_{gc,out} + 7.5\,\text{bar}$.

Environmental Advantage (ODP = 0, GWP = 1)

Natural refrigerant R744 replaces HFCs/HFOs with zero ozone depletion potential and GWP = 1, complying with EU F-Gas and Kigali amendments.

Key Engineering Assumptions

Supercritical gas cooling without phase change in the high-pressure heat exchanger.
Isenthalpic expansion through the high-pressure valve (HPV).
Applicable to commercial supermarket refrigeration, transport cooling, and EcoCute heat pumps.

ThermoFluidCalc Engineering Report