Tuesday, 11 March 2014

Through a glass darkly

From Wikipedia

The delightfully batty Click Green informs us of a wizard idea for generating electricity via our windows.

Scientists have developed ultra-thin solar panels that could be attached to windows to generate electricity without blocking out the light.

Super - but how does it work? If the light isn't blocked then how does it generate the electricity? 

Because the PV panel is so thin, 95% of the light just passes through – but a tenth of the remaining five percent, which are absorbed by the material, are converted into electrical power. Therefore, the internal efficiency is quite high.

A tenth of five percent is 0.5%. Doesn't sound such a wizard idea after all. Maybe heaps and heaps of subsidy will sort that out... but wait a minute...

...even the minute amount of absorbed light is helping to warm the interior of the house. Presumably that could be a problem - especially if these new windows actually create a net energy loss to the house which could be the case here in the UK.


Sam Vega said...

An energy loss to the house, but a gain to subsidised new businesses.

On the topic of sun-warmed houses, I was talking to a local builder who said that he wanted to build all his new houses with a south-facing conservatory which has a black slate floor. Apparently, even wintry sun warms up the slate, and opening the doors into the rest of the house can massively offset the central heating bill as it wafts through.

A K Haart said...

Sam - our kitchen faces west but has large windows and a black slate floor. We get a similar effect even at this time of year.

Sackerson said...

My wife's uncle said "quarter inch plate" glass (double thickness) is as good as double glazing, and doesn't have a seal to break and mist up the glass like dg.

A K Haart said...

Sackers - interesting comment because I've often wondered about that. Glass is a fairly good heat insulator and quarter inch plate glass would virtually last forever.

James Higham said...

Why would there be a net energy loss?

A K Haart said...

James - if the solar panel generates less energy than is absorbed as heat by the interior of the house when the panel isn't used.