📋 Case Study
District Heating Network Seasonal TES with Stratified Water Tank
Summer solar thermal surplus (90°C) must be stored for winter space heating (60°C return), requiring 6-month retention
🏗️ Project Overview
Vancouver Renewable Energy Hub, Canada
🎯 Challenge
Summer solar thermal surplus (90°C) must be stored for winter space heating (60°C return), requiring 6-month retention
🔧 Design Approach
120,000 m³ insulated concrete tank with diffuser-based thermocline management and active destratification bypass
📐 Design Diagram
AI-generated project design illustration
📐 Key Calculations
Annual Thermal Loss Rate
Q_loss = U·A·ΔT_lm·t
Result: 2.1%
Below ASHRAE 90.1-2022 seasonal loss threshold of 2.5%
Diffuser Velocity Criterion
v_jet ≤ 0.3·√(g·Δρ/ρ)
Result: 0.18 m/s
Prevents mixing while ensuring full tank charging in ≤72 hrs
📊 Results
Seasonal round-trip efficiency 78.3%, 14.2 GWh annual solar heat utilization, avoided 1,840 tCO₂e/year💡 Lessons Learned
- •Concrete liner chlorides limited to <0.02% to prevent reinforcement corrosion over 50-yr design life
- •Diffuser clog risk necessitated redundant ultrasonic flow monitoring
✅ Key Takeaways
- 1Concrete liner chlorides limited to <0.02% to prevent reinforcement corrosion over 50-yr design life
- 2Diffuser clog risk necessitated redundant ultrasonic flow monitoring