Energy and Thermal Physics

Salty storage

Stories from Physics for 11-14 14-16 IOP RESOURCES

As discussed above, the use of solar panel technology requires systems that can store energy and release it when solar power output falls. A potential solution to this problem is to use a body of water, such as a lake, to store solar energy. However, convection currents set up in the water result in efficient energy loss from the water and, during a day, the temperature of a pond may vary by only a few degrees. If convection currents could be inhibited, the transfer of energy from the pond would be reduced leading to a significant water temperature rise and more effective solar energy storage. One way to do this is to dissolve salt into a pond. Due to the difference in densities of high and low salinity water, saltwater will form a natural concertation gradient, a halocline, with concentration increasing with depth. In a solar pond, a halocline is created. When solar radiation warms the dense highsalinity water near the pond’s floor, convection is limited as the high-salinity water does not mix readily with the low salinity water in the layer above. Using this technique, researchers have managed to create ponds that can reach up to 90°C simply from solar heating. From the 1950s, researchers in Beit Ha’aravah in Israel have used a 210,000 m 2 solar pond to generate a maximum of 5 MW of power at an efficiency of around 1%.


appears in the relation ΔEΔt>ℏ/2 ΔQ=mcΔθ E=hf E ∝ A^2
has the special case Photon Energy
is used in analyses relating to Emission/Absorption Spectra Phase Change
Limit Less Campaign

Support our manifesto for change

The IOP wants to support young people to fulfil their potential by doing physics. Please sign the manifesto today so that we can show our politicians there is widespread support for improving equity and inclusion across the education sector.

Sign today