8
$\begingroup$

Spacecraft in terrestrial Solar System typically use PV cells to power their instruments. As the referenced Wikipedia article writes,

Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect.

PV meant for operation in vacuum differ from those meant for use on Earth.

Venus is closer to Sol than Earth. In orbit it receives greater radiant energy from Sol. It follows a PV cell may deliver more power. This may vary from one cell design to another.

For instance,

The ZTJ datasheet writes to convey the cell is capable of providing 2.726V (open circuit), and 17.4mA (short-circuit).

  • How much more power could this cell deliver in Venerean orbit?
  • Since all PV cells, regardless of design, would encounter similar solar radiance would it follow the power generation of all PV cells may increase in corresponding proportion?
| improve this question | |
$\endgroup$
  • 2
    $\begingroup$ From a relative sense, Venus is ~0.72 AU from the sun, meaning via the inverse-square law, it gets ~1.93 times as much solar-energy per unit of area as at earth orbit. That said, I don't know whether PV efficiency will change if you double the sunlight coming in. $\endgroup$ – john3103 Sep 23 '13 at 21:34
  • 1
    $\begingroup$ I also wonder if the arrays degrade faster because of an increased rate of radiation damage... $\endgroup$ – user29 Sep 23 '13 at 23:14
  • $\begingroup$ @Chris: PV for space applications are usually 'hardened'. The manufacturer whose datasheet is mentioned also produce PV cells for terrestrial applications but you're right, there might be more damage too $\endgroup$ – Everyone Sep 24 '13 at 3:47
4
$\begingroup$

That depends on a lot of factors but if we just look at the irradiance factors we can make a quick comparison.

STC in an acronym for “Factory Standard Test Conditions,” which is 1,000 watts per square meter solar irradiance, 1.5 Air Mass and 77 degrees Fahrenheit cell temperature.

PTC is an acronym for “Photo Voltaic USA Test Conditions,” which were developed at the PV USA test site at the University of California Davis. The PTC rating represents a more real life condition of 1,000 watts per square meter solar irradiance, 1.5 Air Mass, 68 degrees Fahrenheit ambient temperature at 33 feet above ground level and wind speed of 1 meter per second.

So a panel's rating is based on 1,000 watts per square meter. In orbit this is a little stronger 1361 ⁠watts per square meter. Venus's solar radiance is about 2613.9 watts per square meter.

A panel rated at 100W on earth, would produce 136 watts in space and 261 watts around Venus. This assumes the same environmental conditions, but basically you get about 2x the power.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.