solar module cooling

Saudi scientists have tested several cooling technologies for solar panels and have found that active techniques work better than passive ones under harsh climatic conditions. The most effective one consists of a system based on four heat pipes immersed in a box of liquid, as liquid bulk, integrated with the back of the solar panel.

Academics have utilized three PCMs, known as RT26, RT35, and RT42, and decided to pack them ascendingly depending on their melting points and heat-flow direction. The system is claimed to allow lower melting rates and longer thermal management of the modules.

The proposed technique is based on radiative cooling and consists of a glass coating made with a two-dimensional subwavelength nanostructured grating, which is imprinted in soda-lime glass and has enhanced mid-infrared emissivity, and a micro-structured grating. The temperature decrease provided by the nano-micro-grating coating was found to be approximately up to 5.8 degrees Celsius.

Turkish researchers have developed a cooling technique in which water is sprayed via an air-assisted external mixing flat fan nozzle. The system can produce smaller droplet sizes to ensure the even distribution of water on panels.

Scientists in China have analyzed the radiative cooling techniques used in combination with solar energy systems such as PV arrays, solar thermal collectors, and concentrated PV installations. They identified five major system typologies based on functionality and working time.

New research from Australia has shown that vortex generators and glass texturing have so far proved to be the most effective solutions among the novel methods explored for lowering the temperature of solar panels.

Indian scientists tested four kinds of phase change materials (PCMs) for solar module cooling in building-integrated photovoltaics. The PCMs were encapsulated with the PV system and the building envelopes and were also found to be beneficial to the thermal comfort inside the buildings.

French scientists have proposed the use of radiative sky cooling as a passive cooling technique to cut PV module temperatures by 10 C. They claim the method could improve performance by more than 5 W/m2.

A French-Lebanese research group has proposed a way to cool down PV modules by using air exhausted from heating, ventilation, and air conditioning (HVAC) systems. They showed that array performance improves when the cooling load rises.

Iranian scientists have assessed a new active approach for solar module cooling based on water spraying. Water sprayed from different angles can reduce the operating temperature of PV modules, with limited water consumption. However, the team noted that they have yet to assess the economic viability of the system.