Hydronic System Engineering
Comprehensive technical specifications for underfloor heating pipe systems.
-
Pipe Specifications
- PEX-A Rating: 200°F/80 psi
- Wall Thickness: 0.125"-0.157"
- Oxygen Barrier: 0.1 g/m³/day
- Bend Radius: 5x diameter
- Thermal Expansion: 1.1"/100ft/10°F
- Burst Pressure: 800+ psi
-
Flow Characteristics
- Reynolds Number: 2300-4000
- Head Loss: 0.2-0.4 ft/100ft
- Flow Rate: 0.3-0.6 GPM/loop
- Velocity: 1.5-4 ft/sec
- Pressure Drop: 1.5-3.0 psi/100ft
- Water Volume: 0.016 gal/ft
-
Thermal Properties
- Conductivity: 0.95 BTU/hr·ft·°F
- R-value: 0.67 ft²·°F·h/BTU
- Heat Output: 25-35 BTU/ft²
- Delta T: 15-20°F typical
- Response Time: 20-40 minutes
- Efficiency: 85-95%
Installation Parameters
Critical specifications for optimal system performance:
-
Loop Design
- Max Length: 250-400 ft/loop
- Spacing: 6-12 inches
- Coverage: 50-150 ft²/loop
- Depth: 1.25-2 inches
- Manifold Ports: 2-12
- Circuit Balancing: ±5%
-
Substrate Requirements
- Compressive Strength: 3000+ psi
- Thickness: 1.5-3 inches
- Flatness: ±1/8" in 10ft
- Moisture Barrier: 6-10 mil
- Insulation: R10-R20
- Joint Spacing: 12-15 ft
-
System Controls
- Supply Temp: 90-140°F
- Differential: 7-10°F
- Mixing Valve: 3/4"-1.5"
- Pump Head: 10-25 ft
- Zone Control: 24V AC
- Response: 1°F accuracy
Performance Metrics
Key specifications for system evaluation:
-
Heat Distribution
- Surface Temp: 75-85°F
- Uniformity: ±2°F
- Edge Losses: 5-10%
- Stratification: <4°F
- Recovery Rate: 1-2°F/hour
- Comfort Index: 0.9-1.0
-
Energy Efficiency
- COP: 3.5-4.5
- Distribution Loss: <5%
- Standby Loss: 0.2-0.4%/hr
- Cycling Loss: 2-4%
- Annual Efficiency: 90-95%
- Energy Use: 0.4-0.6 W/ft²
-
System Durability
- Design Life: 50+ years
- Warranty: 25-30 years
- Maintenance: Annual
- Chemical Resistance: pH 6.5-8.5
- UV Resistance: 6 months
- Freeze Protection: -40°F