🔥 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

🔥 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

Operating Service Mode:

Room Floor Area A_floor [m²]:

Pipe Pitch / Spacing W [mm]: Standard: 100, 150, 200, 250 mm

Floor Covering Resistance R_λ,B [m²·K/W]: Tiles: 0.015, Parquet: 0.08, Carpet: 0.15

💧 Hydronic Temperatures & Room State

Water Supply Temp T_w,in [°C]:

Water Return Temp T_w,out [°C]:

Room Design Air Temp T_i [°C]:

Room Relative Humidity RH [%]: Critical for cooling dew point

EN 1264 Formulations:
• Specific Output: q = B · Δθ_H [W/m²]
• Floor Surface Temp: T_F = T_i ± (q / α) [°C]
• Heating Limit: T_F ≤ 29°C (occupied spaces)
• Cooling Limit: T_F ≥ T_dew + 1.0°C (dew point safety)

📊 Radiant Output Results

📊 Output Summary
💾 Fortran Source

Specific Thermal Heat Flux

q = 125.4 W/m²

⚠️ EXCEEDS EN 1264 COMFORT LIMIT (TF > 29°C)

Q = 1.50 kW

Mean Floor Surface Temp (T_F) 35.61 °C Max limit: 29.0 °C

Total Room Thermal Output 1.50 kW 5133 BTU/h

Hydronic Water Flow Rate 259.3 L/h 0.07 L/s (ΔT=5°C)

Room Dew Point (T_dew) 15.76 °C Margin = +19.8 °C

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

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

=================================================================
 THERMOFLUIDCALC — EN 1264 UNDERFLOOR RADIANT REPORT
=================================================================
Case Title                 : Bathroom High-Comfort Dense Pitch Floor Heating
Operating Service Mode     : Radiant Heating
Floor Area / Pipe Pitch    : 12.0 m2 / 100 mm
Covering Thermal Resistance: 0.010 m2.K/W
Supply / Return Water Temp : 40.0 °C / 35.0 °C
Room Air Temp / RH         : 24.0 °C / 60.0 % (Dew point = 15.76 °C)
-----------------------------------------------------------------
SPECIFIC THERMAL HEAT FLUX : 125.36 W/m2
Mean Floor Surface Temp    : 35.61 °C
EN 1264 Comfort Compliance : ⚠️ EXCEEDS EN 1264 COMFORT LIMIT (TF > 29°C)
Total Heating/Cooling Load : 1.50 kW (5133 BTU/h)
Hydronic Water Flow Rate   : 259.3 L/h (1.14 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 $c_p = 4.186\,\text{kJ/(kg·K)}$.

ThermoFluidCalc Engineering Report