A photovoltaic-specific heating module (PVT module) converts sunlight into electricity via PV cells while simultaneously capturing the excess heat to produce usable thermal energy, improving overall system efficiency.

Core Working Principle

A photovoltaic-specific heating module integrates photovoltaic (PV) cells with a thermal collector in a single panel. The PV cells convert sunlight into electricity through the photovoltaic effect, generating direct current (DC) power. However, during this process, a significant portion of solar energy is converted into heat, which raises the temperature of the PV cells and reduces their electrical efficiency . To address this, PVT modules incorporate a heat transfer system, typically consisting of tubes or channels beneath or behind the PV cells, through which a heat transfer fluid (such as water, glycol, or air) circulates. This fluid absorbs the excess heat from the PV cells, cooling them and maintaining higher electrical efficiency while simultaneously producing thermal energy that can be used for space heating, water heating, or industrial processes .

Efficiency and Energy Utilization

By combining electricity and heat generation in one module, PVT systems achieve higher overall energy efficiency than standalone PV or solar thermal systems. For example, while conventional PV panels have an electrical efficiency of around 20%, PVT modules can achieve over 80% total efficiency by capturing both electrical (≈20%) and thermal energy (≈60%), . The cooling effect of the thermal collector also reduces the PV cell temperature, mitigating efficiency losses caused by overheating .

Practical Implementation

In practice, PVT modules can be used in residential, commercial, and industrial applications. The heat transfer fluid can be directed to hot water tanks, underfloor heating systems, or heat exchangers, while the electricity generated powers household appliances or is stored in batteries . Some systems use intelligent controllers to optimize the distribution of electricity and heat, ensuring that surplus PV electricity is efficiently converted into thermal energy when needed .

Advantages

• Dual energy output: Simultaneous generation of electricity and heat from the same surface area.
• Improved PV efficiency: Cooling effect reduces electrical losses due to high temperatures.
• Space and cost efficiency: One module provides both energy forms, reducing roof space requirements.
• Environmental benefits: Reduces reliance on fossil fuels and lowers CO₂ emissions . In summary, a photovoltaic-specific heating module works by capturing both the electrical and thermal energy of sunlight, using PV cells for electricity and a heat transfer system to collect and utilize the otherwise wasted heat, resulting in a highly efficient and versatile solar energy solution.