In order to produce electrical power after the sun has set, we consider an alternative photovoltaic concept that uses the earth as a heat source and the night sky as a heat sink, resulting in a “nighttime photovoltaic cell” that employs thermoradiative photovoltaics and concepts from the advancing field of radiative cooling.
In fact, a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime, according to a concept paper by Munday and graduate student Tristan Deppe.
That's no joke. In fact, a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime, according to a recent concept article. What if solar cells worked at night?
To help supplement solar power technology, scientists are proposing the use of a new type of solar cell, a nighttime solar cell if you will. These cells are driven by radiative cooling, whereby at night they release radiative heat built up over the day and generate electricity.
The article was published in, and featured on the cover of, the January 2020 issue of ACS Photonics. Munday, who recently joined UC Davis from the University of Maryland, is developing prototypes of these nighttime solar cells that can generate small amounts of power. The researchers hope to improve the power output and efficiency of the devices.
Harvesting energy from the temperature difference between photovoltaic cell, surrounding air leads to a viable, renewable source of electricity at night. About 750 million people in the world do not have access to electricity at night. Solar cells provide power during the day, but saving energy for later use requires substantial battery storage.