What is Passive Solar and How Does It Work?

What is Passive Solar and How Does It Work?

With an increased focus on greener building and energy efficiency, the term “passive solar” is being used more and more. Not to be confused with solar panels, passive solar is the use of the natural environment in a way that will optimise the internal temperature of a home. Rather than relying heavily on mechanical cooling or heating systems, a passive solar design will instead focus on building in a way that encourages the retention of warmth in winter and the reflection of heat in summer.

A home with a well thought out solar design will collect heat from the sun and store it in the “thermal mass” of the building (dense materials like concrete and brick that retain heat). Engaging a builder who has experience in passive solar design will go a long way towards improving the energy efficiency of a new house, as passive solar designs will vary based on what climate the home is situated in. Typical methods for improving passive solar include:

  • South Facing Windows: To make the most of the suns natural warmth, windows in the main living areas should face towards the south and be free of shading during the winter months when the sun is lower. If the roof overhang is correctly sized, then this will block excessive heat during the warmer months (when the sun is higher); alternatively, the installation of an awning or shutters can have a similar effect.
  • Thermal Mass: Building materials with thermal mass will absorb heat during the day and then release it slowly at night when the temperature drops. A well-insulated home with products such as brick, masonry or concrete (all commonly used in construction) will assist with warming the house in winter and cooling it down in summer.
  • Energy Efficient Windows: Some people may express concern that installing windows will be counterproductive to passive solar design, but this is not necessarily the case. Energy efficient windows block ambient outside temperature (whether it is cold or hot), while still allowing radiant heat to pass through. This means that a home with energy efficient windows will still benefit from winter sunlight, but with reduced heat loss in winter and improved retention of warmth in winter.

A home with optimal passive solar design will be comfortably cool in summer, warm and cozy in winter and obtain a good deal of sunlight all year round. Although a greater level of energy efficiency can be achieved when passive solar is a consideration before a home is built, existing houses can still benefit from these concepts. Simple and effective steps such as installing shutters, upgrading window glazing or increasing insulation can all contribute to an improved passive solar design. Although some of these tasks could be completed by homeowners, engaging the services of a professional may save time and money in the long run.

Houses that are constructed with a passive solar design will effectively reduce the need to rely on mechanical heating and cooling systems, thereby lowering power usage, minimising utility bills and benefiting the environment.

Solar windows are seeing a massive boost in popularity as the technology improves. We’re looking forward to see where the tech is going for this and also passive renewable energy. 

 

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Printable Solar Panels / Cells – A Primer.

Printable Solar Panels – at some point it may be possible to use a simple desktop inkjet printer to print your own solar cells. We’re a while off that yet, but with great advancements in the technology over the last couple of years, let’s take a look at what the future holds for printed solar cells!

Printable Solar Panels

Printable Solar Panels - University of Newcastle
Printed Solar Cells – University of Newcastle (source: abc.net.au via University of Newcastle)

We wrote last week about the University of Newcastle and their foray into printed solar cells – today we’re going to take a bit of a deep dive into the situation and see where we can expect this technology to go in the next few years. 

The University of Newcastle are reporting that their latest tests in Newcastle brings them “about two years” away from launching their product onto the commercial solar market. Leading the charge has been University of Newcastle physicist Professor Paul Dastoor, who created the electronic inks which are used to print the flexible solar panels.

The process is According to the ABC, semi-conducting ink is printed on a transparent plastic sheet for the first layer, and then layers are printed on top of the other, until the cells are about 200 microns thick. For reference, human hair is around 50 microns. After that, a “top contact layer” is done again, reel-to-reel, using a technique known as sputter coating, according to Professor Dastoor.

They estimate the cost of their modules at less than $10 per square metre which is extremely cheap – the main problems are the efficiency of the printed solar panels and ensuring there’s enough space for them as it’ll take quite a lot of room on a roof. They use a lot of plastic to manufacture as well so looking at ways to recycle the waste of printed solar cells is extremely important. For that reason, in six months Professor Dastoor and his team will pull the printed solar cells off the Melbourne roof they’re currently on and investigate ways to minimise environmental waste. 

 

 

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Printed Solar Cells | University of Newcastle

The University of Newcastle has been able to deliver printed solar cells at a production cost of less than $10 per square metre. They are now powering a Newcastle business and showing results in the wild. Amazing steps forward for solar technology, and in our own backyard! How long until we can print solar cells at home using inkjet printers?

Printed Solar Cells – Breakthrough Technology

University of Newcastle physicist Professor Paul Dastoor has created electronic inks which are used to print the flexible solar panels – offering “unprecedented affordability” and could help solve the energy crises in New South Wales and Australia-wide.

“We are changing the climate, we know it’s because burning fossil fuels and we have to shift to renewables, even if leaders in Canberra can’t understand that,” he told AAP via the Bega District News.

“This technology has the potential to be enormously scalable … it’s fast, it’s low cost and doesn’t require anything special.”

The team are able to print hundreds of metres of solar cells at the Centre of Organic Electronics at the University of Newcastle. If a commercial scale printer were obtained, this could easily be upgraded to kilometres of cells. 

“The low cost and speed at which this technology can be deployed is exciting as we need to find solutions, and quickly, to reduce demand on base-load power – a renewed concern as we approach another summer here in Australia,” Professor Dastoor said.

 
Printed Solar Cells via Paul Dastoor
Printed Solar Cells via Paul Dastoor of University of Newcastle (source: newcastle.edu.au)

Around 200 square metres of the printed solar panels has been installed at an industrial site owned by logistics company CHEP in Beresfield, near Newcastle.

This is a fantastic step forwards for solar panel technology People who are wanting to install solar into a rental property or those who don’t have access to a roof (apartment solar) will be licking their lips at the possibility. 

According to Wikipedia, these printed solar cells have a few main drawbacks:

  1. The efficiency of inket solar cells is “too low to be commercially viable” 
  2. Indium is a rare material and could be gone in 15 years.
  3. The ink needs to be weather resistant and can survive harsh conditions.

It looks like the efficiency of Dr Dastoor’s printed solar panels is around 2-3%, but at only A$10 per square metre when manufactured at scale, it looks like these modules are certainly commercially viable, even if they’re not the most efficient cells in the world. 

In six months they will remove the test panels from the CHEP roof and have a look at recycling the material. Professor Dastoor and his team will also run some statistics on how well the printed solar was able to perform. We’ll keep you updated! 

If you want to learn more about flexible solar panel tech, please click here

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Solar Tarp – foldable, portable solar power.

California based Lipomi Research Group are working on creating a solar tarp – which would have myriad uses for society. Let’s learn more about how these upgraded solar panels could help parts of the world where they don’t have access to regular electricity – and some of the technological challenges they’re facing trying to complete the project.

About the Solar Tarp technology

Prototype Solar Tarp Sample - University of California
Prototype Solar Tarp Sample – University of California (source: theconversation.com)

The Lipomi Research Group are focused on “identifying ways to create materials with both good semiconducting properties and the durability plastics are known for – whether flexible or not”.  They’ve been tinkering with perovskite solar cells, which are 1/1000 the thickness of a silicon layer in a solar panel. 

Darren Lipomi of the Lipomi Group, who is also a Professor of Nanoengineering at the University of California, said that their goal is to create flexible solar panels which are as efficient as conventional silicon but don’t have some of the drawbacks of it.

The goal is to develop flexible solar panels which are thin, lightweight, and bendable. Lipomi is calling their idea a ‘solar tarp’ – which refers to a solar panel which can be expanded to the ‘size of a room’, but balled up to the size of a grapefruit when not in use. The issues here are finding a molecular structure to make the solar panels stretchable and tough – this involves replacing the silicon semiconductors with materials such as perovskite. 

They’re also taking a look at polymer semiconductors / organic semiconductors (based on carbon, and used in place of perovskites or silicon in a solar cell). These aren’t as efficient, but are far more flexible and extremely durable.

According to The Conversation, the sunlight that hits the earth in a single hour contains more energy than the whole planet uses in an entire year – so there’s plenty more work to do on improving how we utilise the sun! We’ll keep an eye on the solar tarp project and let you know when it reaches the next stage.

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Container Roll Out Solar System – Portable Solar

ARENA (the Australian Renewable Energy Agency) have awarded a grant to ECLIPS Engineering to design, manufacture, and test its ‘diesel killer’ portable solar offering, the Container Roll Out Solar System (CROSS). 

Container Roll Out Solar System – ECLIPS

Container Roll Out Solar System CROSS
Container Roll Out Solar System CROSS (source: eclips.engineering)

ECLIPS Engineering (formerly Sea Box International) are a Canberra based engineering firm hoping to do their part to help Australia do away with diesel generators in situations where a temporary power supply is required. They have created factory assembled 20 and 40 foot long solar panel arrays which fit in shipping containers and have minimal setup / teardown time. 

According to RenewEconomy, each 20ft unit has 2.1kW of power, and 7 of them can fit in a shipping container. The 40ft units has up to 4.3kW and can also fit seven to a container. 

ARENA have given CROSS $703,468 to to help the project, which has aims more lofty than just replacing diesel generators at work sites – the Container Roll Out Solar System could also help in defence situations, disaster recovery, for humanitarian needs, or for ‘temporary network augmentation’ (i.e. helping the grid if it’s malfunctioning or under severe stress).

ARENA CEO Ivor Frischknecht spoke about funding the project, and how they hope to see an eventual replacement of diesel generators in 99% of cases:

“CROSS units can be deployed in off-grid and fringe-of-grid areas, displace or offset diesel consumption and improve the security of existing networks,” he said.

“These renewable options can reduce some of the barriers to entry for potential renewable power users in remote locations, including short project durations and where power systems need to be periodically relocated,” Frischknecht said.

“Renewable energy can provide an emissions-free, silent energy system that could replace diesel generators in the long run.”

We’ve already reported on the Maverick by 5B, which is another prefab, low-cost ground mounted solar array – it’s great to see some more options available to try and minimise the amount of diesel generators used as a temporary power supply. 

We’ll keep you posted how the project goes and what the next steps are!

 

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