Floating solar arrays (also called floating photovoltaics or FPVs) are solar panels installed on bodies of water, such as reservoirs, lakes, or retention ponds. They offer renewable energy generation while reducing land use. Beyond electricity generation, floating solar panels can also affect a building’s water-side energy efficiency, which may influence EPC (Energy Performance Certificate) assessments for properties using water-based heating or cooling systems.
EPCs typically evaluate a property’s energy efficiency based on standard building systems, insulation, and heating/cooling methods. Integrating floating solar arrays adds complexity because it changes the thermal dynamics of water used in heating/cooling systems.
Key Impacts
Reduced Water Temperature Fluctuations
Floating solar panels shade the water surface, reducing heat gain in summer and heat loss in winter.
Water-side HVAC systems (like hydronic heating or cooling) may operate more efficiently due to more stable water temperatures.
Lower Pumping Energy Requirements
By moderating water temperatures, floating arrays can reduce the energy required to heat or cool water circulated through the building, potentially improving overall energy efficiency.
Enhanced System Longevity
Stable water temperatures can reduce stress on pumps, pipes, and heat exchangers, indirectly contributing to energy savings and lowering lifecycle energy costs.
Challenges for EPC Modeling
EPC software (SAP/RdSAP) assumes standard water temperatures for calculations.
Floating solar arrays introduce dynamic thermal conditions that EPC models cannot easily account for, potentially underestimating the building’s true water-side energy efficiency.
Practical Implications
Buildings using floating solar-equipped reservoirs may be more energy-efficient than their EPC suggests.
EPC assessments may not fully capture reductions in heating/cooling energy due to the moderated water temperatures.
Accurate evaluation may require supplementary thermal modeling or detailed data from the system installer.
Recommendations
Provide detailed specifications of the floating solar system and water temperatures to your assessor.
Combine floating solar with other energy efficiency measures like insulation and smart HVAC controls.
Consider documenting actual energy usage to complement EPC calculations.
Use professional EPC services, such as our Residential EPC or Same-Day EPC assessments.
Check our Pricing Plan for more information or Contact Us to schedule a consultation.
Conclusion
Floating solar arrays can enhance water-side energy efficiency for properties with hydronic or water-based systems. While standard EPC models may struggle to reflect these gains accurately, proper documentation and advanced assessment methods can help ensure your EPC rating better represents your property’s real energy performance.
