Photovoltaic Thermal System Efficiency

Photovoltaic thermal (PV-T) systems combine photovoltaic cells with thermal collectors to capture both electrical and heat energy from sunlight. By removing excess heat from the PV modules, these systems maintain lower photovoltaic temperatures, improving electrical conversion efficiency while simultaneously harvesting useful thermal energy. Typical configurations include liquid-cooled and air-cooled collectors, building-integrated variants and concentrating PV-T units. Efficiency is characterised by two metrics: electrical efficiency, the proportion of incident solar irradiance converted to electricity; and thermal efficiency, the fraction converted to usable heat. Advances in selective coatings, nanofluid coolants and dynamic control strategies have raised overall solar utilisation efficiencies above 60 per cent in some prototypes. At the system level, PV-T arrays can be integrated into combined heat and power, desalination, cooling and domestic hot-water schemes, offering substantial carbon mitigation and energy cost savings. Despite these benefits, challenges remain in optimising material durability, reducing manufacturing costs and developing robust models that account for transient climatic variations. Improved design methodologies and standardised performance assessments are vital to accelerate deployment and support global decarbonisation pathways.

Research from Nature Portfolio

Recent studies have demonstrated bio-inspired approaches to passive thermal management in PV-T systems. A hybrid multi-generation ‘photovoltaic leaf’ employs an eco-friendly transpiration structure that mimics plant cooling. Under standard test conditions it removed nearly 600 W/m2 of heat, reducing cell temperature by around 26 °C and boosting electrical efficiency by over 13 per cent. Importantly, the recovered thermal energy can be co-generated as heat and freshwater, elevating overall solar utilisation efficiency from the mid-teens to above 70 per cent in a single compact module. This work underscores the potential of nature-inspired materials and architectures to enhance PV-T performance without active pumping or complex control systems.

Photovoltaic Thermal System Efficiency publication trend

The graph below shows the total number of articles in photovoltaic thermal system efficiency across all publications each year (not limited to Nature Index journals).

Technical terms

Photovoltaic thermal (PV-T) system: A combined assembly that simultaneously generates electricity and heat from solar radiation.

Electrical efficiency: The ratio of electrical energy output to solar energy incident on the PV module.

Thermal efficiency: The ratio of useful thermal energy harvested to solar energy incident on the thermal collector.

Phase change material (PCM): A substance that absorbs or releases latent heat during phase transitions to regulate temperature.

Biomimetic transpiration structure: An engineered material that uses evaporative cooling principles inspired by plant leaves.

References

1. High-efficiency bio-inspired hybrid multi-generation photovoltaic leaf. Nature Communications (2023).
2. A review of solar hybrid photovoltaic-thermal (PV-T) collectors and systems. Progress in Energy and Combustion Science (2023).
3. Advanced cooling techniques of P.V. modules: A state of art. Case Studies in Thermal Engineering (2020).
4. Hybrid photovoltaic-thermal solar systems for combined heating, cooling and power provision in the urban environment. Energy Conversion and Management (2017).