Dynamic thermal mass walls, constructed from materials like phase-change plaster or concrete with high heat capacity, can absorb and release heat throughout the day. This moderates indoor temperatures and reduces HVAC loads. However, these dynamic properties introduce challenges for Energy Performance Certificate (EPC) assessments.
1. Understanding Dynamic Thermal Mass Walls
Definition: Walls that store and release heat dynamically, buffering indoor temperature fluctuations.
Energy Efficiency Benefits: Reduce peak heating and cooling demand, enhance occupant comfort, and potentially lower energy bills.
Common Materials: Concrete, brick, phase-change materials (PCMs), and specialized composites.
Learn more about advanced EPC modelling on our residential EPC page.
2. EPC Modelling Challenges
Static Assumptions in Standard EPC Software: Many EPC tools assume fixed thermal properties, failing to account for dynamic heat storage and release.
Delayed Heat Transfer Effects: Thermal mass introduces phase delays between energy input and internal temperature response, complicating simplified EPC calculations.
Interaction with HVAC Systems: Dynamic walls may reduce system cycling or shift peak loads, affecting predicted energy consumption.
Data Requirements: Accurate modelling requires material-specific thermal capacity, conductivity, and PCM transition temperatures.
For expert assistance with complex EPC models, visit our same-day EPC services.
3. EPC Implications
Potential Underestimation of Efficiency: If dynamic effects are ignored, EPC ratings may not fully reflect energy savings.
Influence on Heating and Cooling Loads: Proper modelling of thermal mass can show reduced energy use and improved EPC scores.
Need for Advanced Simulation: Dynamic building simulations (EnergyPlus, IES-VE) are often required for accurate ratings.
For guidance, check our about us page or contact us.
4. Best Practices for EPC Assessment
Use dynamic simulation software to capture thermal mass effects accurately.
Include precise material properties in EPC inputs, including specific heat and density.
Model occupancy and HVAC schedules to reflect actual building operation.
Document wall composition and retrofits for accurate EPC assessment.
Conclusion
Buildings with dynamic thermal mass walls require advanced EPC modelling techniques to accurately predict energy performance. Proper consideration of thermal storage effects, material properties, and system interactions ensures reliable EPC ratings and demonstrates the true energy efficiency of the building.
