Difference Between Solar Modules and Solar Panels

panels under module glass reflect differences in the sky

You say “panel,” I say “module”

Sticklers know the difference between solar panels and solar modules.

panels under module glass reflect differences in the sky
Black framed modules; the panels under glass are also black, but appear sky-color here.

The solar module is the framed unit that contains within it the solar panels consisting of multiple solar photovoltaic (“PV”) cells. The cells are usually blue or black.

Modules look pretty much like a large, chrome or black, glass-fronted, poster frame, with the panels inside. Manufacturers make newer modules slimmer and lighter weight.

Modules connect to each other in an array with short cables, usually on rails attached to the homeowner’s roof. Installers use one or more arrays, depending on the shape and size of the roof surfaces.

Even though they are different, I’ve used “solar panels” and “solar modules” somewhat interchangeably on the blog. Most people search for “solar panels” online, even though they are looking for modules, but in context, the difference often doesn’t matter.

PV: Just so electricity and water don’t mix…

We often use “PV” or “photovoltaic” to distinguish between solar panels meant to heat water with sunlight, and solar modules meant to generate electricity.

“Photo” comes from the Greek for “light.” For example, a photograph is a graphic image of light. “Voltaic” refers to “volts.”

LISTING AGENT TIP: Real estate listing agents should be clear which type of solar they mean in the listing. It can be difficult to tell the difference in photos. Pool owners, especially, can have either, or both, water and electric, systems.

Photocatalytic Cleaning of Solar Modules

You are probably aware that the catalytic converter in your car reduces pollution.  It does so by converting harmful byproducts of combustion into harmless compounds, using a catalyst.

Dictionary.com gives “chlorophyll” as an example of the catalyst active in photosynthesis. Photosynthesis is the process by which plants use sunlight energy to create chemical energy, with oxygen as a byproduct.

Interestingly, we can also use sunlight to create “self-cleaning” PV modules with a photocatalyst treatment.

A PV module treated with the correct photocatalyst will similarly clean pollutants from both the module and the air around it.  Sunlight, in this instance, activates two processes at once. As it activates the solar cells in the panel to produce electricity, treated panels break down organic compounds, including mildew, pollen, ash, dust, bird droppings, and automobile exhaust.

Detour down an etymological rabbit hole

This post would be considerably longer if I tried to make the connection between “volt” and its root meaning “to turn” (“Please turn on the volts, Honey! It’s getting dark”). However, the use of “volt” comes to us as a nod to Italian physicist Alessandro Volta, who developed chemical processes in batteries.

Correct terminology is a pet peeve of mine, not to be confused with either “PV” or a peavy. If you hear the solar install team say the word, they probably mean “PV” or “photovoltaic.” If “peavy,” it’s bad news, as a peavy is a jack, jimmy, or crowbar, and should not be used to install solar. It would peeve me if it was.

However, few will notice the difference if you say solar “panel” instead of “module.”

Do you have any pet peeves regarding the differences between words like “panel” or “module”? I’ve noticed that when you lead a horse to water, you can’t get him to drink from a lead pipe. Confusing Autocorrect is quiet easy.

Are there any other solar related words you’d like to see defined? Please comment below, and Bookmark, Like, Share, Follow, or Subscribe. Contact me with questions or suggestions.

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