Solar Windows Power Your Home?

A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work. Scientists have demonstrated that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight. Clever clogs.

Quantum dot LSC devices under ultraviolet illumination.
A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum-dot work by Los Alamos National Laboratory researchers in collaboration with scientists from University of Milano-Bicocca (UNIMIB), Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.

“The key accomplishment is the demonstration of large-area luminescent solar concentrators that use a new generation of specially engineered quantum dots,” said lead researcher Victor Klimov of the 
Centre for Advanced Solar Photophysics (CASP) at Los Alamos.
Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry. Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology — quantum dot displays — employed, for example, in the newest generation of the Kindle Fire ™ e-reader.

Light-harvesting antennas

A luminescent solar concentrator (LSC) is a photon management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided towards the slab edge equipped with a solar cell.
Klimov explained, “The LSC serves as a light-harvesting antenna which concentrates solar radiation collected from a large area onto a much smaller solar cell, and this increases its power output.”
“LSCs are especially attractive because in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy generation units,” said Sergio Brovelli, who worked at Los Alamos until 2012 and is now a faculty member at UNIMIB.
Because of highly efficient, color-tunable emission and solution processability, quantum dots are attractive materials for use in inexpensive, large-area LSCs. One challenge, however, is an overlap between emission and absorption bands in the dots, which leads to significant light losses due to the dots re-absorbing some of the light they produce.

“Giant” but still tiny, engineered dots

To overcome this problem the Los Alamos and UNIMIB researchers have developed LSCs based on quantum dots with artificially induced large separation between emission and absorption bands (called a large Stokes shift).
These “Stokes-shift” engineered quantum dots represent cadmium selenide/cadmium sulfide (CdSe/CdS) structures in which light absorption is dominated by an ultra-thick outer shell of CdS, while emission occurs from the inner core of a narrower-gap CdSe. The separation of light-absorption and light-emission functions between the two different parts of the nanostructure results in a large spectral shift of emission with respect to absorption, which greatly reduces losses to re-absorption.
Concept of a Solar Window
To implement this concept, Los Alamos researchers created a series of thick-shell (so-called “giant”) CdSe/CdS quantum dots, which were incorporated by their Italian partners into large slabs (sized in tens of centimeters) of polymethylmethacrylate (PMMA). While being large by quantum dot standards, the active particles are still tiny — only about hundred angstroms across. For comparison, a human hair is about 500,000 angstroms wide.
“A key to the success of this project was the use of a modified industrial method of cell-casting, we developed at UNIMIB Materials Science Department” said Francesco Meinardi, professor of Physics at UNIMIB.
Spectroscopic measurements indicated virtually no losses to re-absorption on distances of tens of centimeters. Further, tests using simulated solar radiation demonstrated high photon harvesting efficiencies of approximately 10% per absorbed photon achievable in nearly transparent samples, perfectly suited for utilization as photovoltaic windows.
Despite their high transparency, the fabricated structures showed significant enhancement of solar flux with the concentration factor of more than four. These exciting results indicate that “Stokes-shift-engineered” quantum dots represent a promising materials platform. It may enable the creation of solution processable large-area LSCs with independently tunable emission and absorption spectra.
 
Sadly this all still just an idea and won’t be in the mainstream market for a few more years. The idea though is  revolutionary. You could plug in your appliances into your WINDOW. Ideal for Kitchen windows, plug in your kettle and make a lovely cuppa powered by the sun, bliss. For more information on the Solar Window click here. Also there are many different companies trying to get their own spin on the Solar Window e.g. New Energy claim they are making a Solar Window that can out perform any commercial Solar Panel by 10 fold. Clearly in the foreseeable future not only will we see Solar Windows hitting the market but a whole range of them specially designed in their own unique ways!
 
I bid you adieu my dear Sirs and Madams!

Any upvc frame colour you like – as long as it’s white?

Not so long ago, if you were choosing upvc double glazing to replace your old windows, then the frame colour choice was usually limited to white, white or… White.

You can’t keep a good plastic extrusion manufacturer down, though, and they quickly caught onto the fact that us homeowners quite like wooden windows – and that if they could make their plastics look a bit more like wood, they might just get a few more sales.

And so it was, that wood grain finish uPVC frames were born, and in the last few years, they have flourished. Nowadays there’s a huge variety of frames and fittings for your fenestration.

White.

White is the original, and is still the most popular colour choice by far. White upvc frames rapidly underwent major improvements soon after they were first developed to battle dis-colouration problems, and modern white frames keep their appearance for many years after manufacture.

White frames, whether they’re casement, bow, bay or sash style continue to look good in any property.

Hardwood.

Cherry – The darker wood colour particularly suited to fascia uses (as it doesn’t show the dirt so much) is a ‘foil’ layer that’s applied at the extrusion manufacturing stage rather than applied by the window company themselves. This makes for an extremely durable finish.

Light Oak – with the look of a more traditional timber frame colour, Light Oak is proving to be very popular and not just in windows. This frame colour looks great on conservatories and doors. Again, the coloured ‘foil’ layer is applied at the extrusion manufacturing stage so it’s a very durable finish.

It is possible to now specify either a colour finish on the outside to blend in with existing brick or stonework, whilst opting for white on the inside to brighten up the room.

Expect to pay around 15% more (than white frames) for one sided colours and around 20% more for 2 sided colours (Oak outside, white inside etc).

Cream.

A newer frame finish that’s quickly found favour with home building developers is Cream.

To our knowledge, it’s not available as a dual-sided colour, rather the colour (like white) runs through the whole of the extrusion from which the frame is made.

It certainly looks distinctive though and if you’re looking for something to really set your property off then cream may be the finish you’ve been looking for. I’ve seen them in period properties as well and they look very good indeed – they don’t have the starkness that white windows sometimes have.

Cream is a relatively new colour and at present will cost around 20% to 25% more than standard white upvc frames.

Black and White.

You don’t see them very often and not every window company deals in them but there are two other frame colours worth mentioning here – black, which has been around for a few years now and a much newer ‘foil white’ and it’s that I want to tell you about.

Like its colour foil counterparts, the white finish is applied at manufacturing so it’s extremely durable. Why choose white ‘foil’ on a white frame? Well one of the advantages of the white ‘foil’ finish is that it gives your frame a very realistic woodgrain finish and unless you’re up close,can easily be mistaken for wood.

Hopefully, as this product becomes more and more available, it will find uses in period buildings etc that were previously unsuitable for upvc frames because of planning constraints.

Expect prices to be around 20% more than standard white frames

Whatever frame you colour or combination of colours you prefer, you’ll find instant online quotes at Windowquoter – double glazing quotes without the need for a salesman to call.