ThermoFluidCalc Engineering Report

Underfloor Radiant Heating & Cooling (EN 1264) — 2026-08-23 20:58:57
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🔥 Underfloor Radiant (EN 1264)

Size underfloor radiant heating and cooling systems per EN 1264, calculating specific heat flux (W/m²), surface temperature limits, and dew point condensation safety.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated
📊 Solver Telemetry ● ACTIVE
👁️ Consultations 38
⚡ Calculs faits 31
💾 Téléchargements 284 📦 Code Fortran 4.4 KB
📅 Mise en service Jun 2026
⏱️ Latence < 1 ms
⚡ Outils & Rapports :
💾 Télécharger Fortran 90

🔥 Underfloor Embedded PEX Pipe Thermal Layer Cross-Section

Real-time thermal flux distribution across screed, insulation & surface finish

📝 Configuration & Presets

🔥 Tile Floor Heating (150 mm pitch) 🪵 Wood Parquet (100 mm pitch) ❄️ Summer Radiant Cooling (16°C) 🚿 Bathroom Comfort
⚙️ Operating Mode & Floor Geometry
Standard: 100, 150, 200, 250 mm
Tiles: 0.015, Parquet: 0.08, Carpet: 0.15
💧 Hydronic Temperatures & Room State
Critical for cooling dew point
EN 1264 Formulations:
• Specific Output: q = B · ΔθH [W/m²]
• Floor Surface Temp: TF = Ti ± (q / α) [°C]
• Heating Limit: TF ≤ 29°C (occupied spaces)
• Cooling Limit: TF ≥ Tdew + 1.0°C (dew point safety)

📊 Radiant Output Results

📊 Output Summary
💾 Fortran Source

Specific Thermal Heat Flux
q = 121.6 W/m²
⚠️ EXCEEDS EN 1264 COMFORT LIMIT (TF > 29°C)
Q = 4.86 kW
Mean Floor Surface Temp (TF) 32.26 °C Max limit: 29.0 °C
Total Room Thermal Output 4.86 kW 16592 BTU/h
Hydronic Water Flow Rate 838.0 L/h 0.23 L/s (ΔT=5°C)
Room Dew Point (Tdew) 8.62 °C Margin = +23.6 °C

📈 Thermal Flux q (W/m²) vs Supply Water Temp

📉 Floor Surface Temp (TF) vs Pipe Pitch (W)

=================================================================
 THERMOFLUIDCALC — EN 1264 UNDERFLOOR RADIANT REPORT
=================================================================
Case Title                 : Residential Living Room Tile Floor Heating (EN 1264)
Operating Service Mode     : Radiant Heating
Floor Area / Pipe Pitch    : 40.0 m2 / 150 mm
Covering Thermal Resistance: 0.015 m2.K/W
Supply / Return Water Temp : 38.0 °C / 33.0 °C
Room Air Temp / RH         : 21.0 °C / 45.0 % (Dew point = 8.62 °C)
-----------------------------------------------------------------
SPECIFIC THERMAL HEAT FLUX : 121.56 W/m2
Mean Floor Surface Temp    : 32.26 °C
EN 1264 Comfort Compliance : ⚠️ EXCEEDS EN 1264 COMFORT LIMIT (TF > 29°C)
Total Heating/Cooling Load : 4.86 kW (16592 BTU/h)
Hydronic Water Flow Rate   : 838.0 L/h (3.69 GPM)
=================================================================

📘 Calculation Methodology & EN 1264 Standards

EN 1264 Calculation Engine

The characteristic emission curves determine the thermal flux $q$ based on logarithmic mean temperature difference $\Delta \theta_H$ and floor resistance:

q = B · ΔθH [W/m²]

Surface Temperature Limitations

  • Heating: Maximum $29^\circ\text{C}$ in living areas ($33^\circ\text{C}$ in bathrooms) to prevent venous foot discomfort.
  • Cooling: Surface temperature must remain $\ge T_{dew} + 1.0^\circ\text{C}$ to prevent slippery floor condensation.

Key Engineering Assumptions

  • Standard $16\times 2\,\text{mm}$ cross-linked polyethylene (PEX-a/b) tubes.
  • Cement screed conductivity $k = 1.2\,\text{W/(m}\cdot\text{K)}$ with 45 mm thickness.
  • Heat capacity of circulating water $c_p = 4.186\,\text{kJ/(kg·K)}$.