Hyperthermia is no joke. Humans need to have access to enough liquids in order to allow the cooling effects of sweating to work. If the body becomes overheated, many systems in the body can crash.
Solar panels have a lot in common with humans in this regard; they don’t work very well when overheated – not surprising when they are positioned to face the sun for most of the day.
Researchers Have Found Out How to Make Solar Panels Sweat
A jubilant Liangbing Hu, from College Park in Maryland University, has made progress developing a state of the art atmospheric water collector. He calls it a highly simple and effective way to instantly boost efficiency by retrofitting existing solar panels with the device.
Materials Scientist, Jun Zhou, from the Science & Technology focused University of Huazhong, says that in this technological field, engineers and scientists have struggled to find a way to boost solar panel power conversion efficiency by 0.1% – an amount that would lead to a significant 1% economic gain.
More Than 25 Degrees Temperature Drops Solar Panel Efficiency
With worldwide solar power capacity at more than 600 gigawatts, global energy provided by the sun currently sits at around 3%. Materials scientists aim to increase that amount x 5 over the next ten years. Most solar panels convert sunlight to electricity using silicon.
Typical solar panel silicon cells can convert approximately 20% of the sun’s rays into current when it hits them. The rest (80%) is turned into heat. This is where the problems arise, because this residual warmth can overheat solar panels by as much as 40°C/104°F.
For every 1 degree over 25°C/77°F, solar panel efficiency drops. This is why solar panels need to be retrofitted with a device that allows them to release this heat.
Cooling Solar Panels: The Research
For many years, researchers have been able to show that by cooling solar panels with water, efficiency and output is significantly improved. Water-cooling systems are even sold by some solar panel installation companies. However, these setups require plentiful supplies of readily available water, in addition to pumps, pipes and storage tanks. This is not the ideal solution to use in dry climates or even developing countries with poor infrastructure.
Welcome to the Atmospheric Water Collector
Materials scientists, like Jun and Liangbing, have been active in designing substances that are able to extract water vapour out of the air, condense it, and turn it into drinking water. The best material for this action so far is a gel that allows for the absorption of precipitation (water vapour) at night. This is the best time for this to happen as it’s when the surrounding air is at its coolest and humidity levels are high.
collecting water to cool down solar panels
This gel is a blend of carbon nanotubes suspended in polymers. Water-magnetizing calcium chloride salts inside the nanotubules cause the vapour to form condensation which then turns into droplets of water. The gel holds the water until released.
When it starts getting hotter during the day, that’s when the gel releases the water. The gel is covered by a transparent plastic in which the water droplets are trapped. Having nowhere else to run to, the condensation stays liquid and flows into an attached storage container.
It is this technology that is being transformed into a coolant material for solar panels. Materials scientists have completed successful research using a 1cm thick sheet of the polymer gel underneath a standard silicon panel.
The idea was to use the condensation the gel had pulled out of the atmosphere during the night to cool down the solar panel during the day. This form of evaporation would then cool down the panel to below 25°C in the same way the sweat evaporating from your skin cools you down.
mechanism
Arid vs. Humid Climates
The amount of gel the researchers needed to attach to the solar panels depended on the climate where they were installed. A dry or arid environment required 1kg/2.2lb gel to cool down a 1 sqm panel. A humid or damp environment required only 0.3kg/0.6lb of gel. This means that water-cooled solar panels would have to be custom-made or custom-retrofitted for each individual climate.
The upshot of the research, however, indicates that this might be a worthwhile installation to consider in the future. Solar panels cooled in this way had lower temperatures by as much as 10°C/50°F, causing the cooler panels to increase electrical output by 15% to 19%.
Are There Any Drawbacks to Atmospheric Water Collecting?
With an increase in solar panel efficiency that significant, people might be asking themselves if there are any drawbacks to adding the polymer gel. Materials scientist, Zhou, counters any doubts with the reassurance that the gel applications are being refined all the time.
In answer to the possibility of the calcium chloride salts dissolving in the rain, he said that the water-based gel is installed underneath the panel where the rain cannot penetrate. In the meantime, Zhou and other materials scientists are working on the creation of a second generation hydrogel that won’t degrade when exposed to rain.
They further state that this technology could expand and be used to trap any dust particles and debris that land on top of solar panels – thus solving yet another power-draining problem at the same time.
Any excess water vapour collected by the gels could be stored and used for drinking water. This would be of huge benefit in desert and arid environments (or in Auckland those days unfortunately).
Water provision capabilities as well as power increases? Sounds like solar panel atmospheric water collectors will be coming to an green energy installation provider to you very soon!
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