The Climate Spectator has an article on research into a solar powered air cooling system which could help reduce the spiralling cost of network transmission expansion required to meet the growing summer peak loads created by air conditioning units - A chilling future for solar power.

Everyone seems pretty comfortable with the idea that the energy from the sun can be captured to heat stuff and create electricity. But what if we were able to use it to address one of Australia’s greatest needs: how to cool things down, particularly the air inside your home; and one of its greatest challenges – reducing peak loads on the network?

This is one of the ideas being developed by the CSIRO at its Energy Research Centre in Newcastle. And the technology – known as Solar Cooling – is now at the point of commercialisation. And it is so simple it can be bolted on to the solar hot water systems that are already so prevalent in suburbia – and add space heating in winter and cooling in summer to the hot water that is already delivered by the solar collectors.

The irony of this development is that it offers the opportunity for a renewable energy source to provide a solution for a problem it is often blamed for creating – rising electricity costs.
The reality is that the greatest component of rising energy bills is the cost of network upgrades, and the biggest reason for these is the growth in peak energy demand, driven largely by the rush to install household air conditioning systems, which now account for around 50 per cent of peak demand on some networks.

Indeed, such is the scale of the rollout of domestic air-con, and its impact on networks, that it now qualifies as the most heavily subsidised sector of the electricity grid – far greater than rooftop solar, or large-scale wind farms.

For every $1000 invested in an air-conditioning system, it is estimated that another $3000 is required to upgrade the network. That translates into an added cost of $100 per year on the electricity bills of those who either choose not to have air-con in their home, or who can’t afford it.

Reducing peak demand is one of the biggest challenges facing energy market operators. In Australia, it is estimated that one quarter of the nation’s electricity costs go to catering for around 40 hours of peak demand – those occasions of extreme temperatures when everyone turns on their air-con at the same time and when the electricity demand is nearly doubled. If this technology based around solar panels on the roof can be rolled out at scale, it could offer one of the best opportunities to significantly lower those peak loads and reduce the need to upgrade and expand networks and help flatten the anticipated spikes in domestic electricity bills.

The principle behind Solar Cooling systems being developed by the CSIRO is simply to integrate technologies that are already understood – the rooftop panels on the roof that heat the water, and which can then be used to heat air; a desiccant wheel to dry the air; and evaporative systems to cool the air.

Stephen White, the manager of the CSIRO’s Energy for Buildings division, says the advantage of this system is that it can operate at relatively low temperatures – 50°C to 70°C – which are common for solar hot water systems.

Incoming hot, moist, humid air is dehumidified using a desiccant such as a silica gel on a rotating wheel to create a dry air stream which is then cooled using an evaporative cooler. The desiccant absorbs the moisture from the air. This material is then stripped of moisture (regenerated) using solar heat.

The CSIRO believes that electricity costs could be reduced by half – and would be a much more efficient use of resources, because the solar collectors would be in use all year round, while a conventional air conditioner system might be in use for just 7 per cent of the time.
“We see it as three in one solar thermal product for the home – a solar hot water system, and space heating in winter, and cooling in summer when the sun is shining the hardest," Dr White says. “It matches very nicely." It is likely that these systems will be able to bolt on to already installed solar hot water systems.

The CSIRO has already developed a prototype called REDEcool which can be used in households and is now looking for a manufacturing partner to help refine the design, and the costs, for mass production. Dr White says the capital cost of the system will be more than the $1000 that people pay for the air-con systems they buy from shops, but it should be cheaper than the $4000 network cost.

Cryptogon has a startling figure for the cost of air conditioning tents used by the US military - Afghanistan: U.S. Spends $20 Billion Per Year for Air Conditioning in Tents.

This astonishing statistic is mentioned in the audio feature on the page linked below.

Via: PRI:

The term we were looking for is “Forward Operating Base” or FOB. The US has many FOBs in Iraq and Afghanistan. The large ones have many tents and other structures where personnel live and work. And all of them need to be heated in the winter, and cooled in the summer. That can take a lot of fuel.

Steve Anderson is a retired Brigadier General who was General David Petraeus’s chief logistician in Iraq. He says the Pentagon should find ways to make structures at FOBs and other military compounds more energy efficient, not only to save money and be greener, but also, to save lives.

The ABC has an article on a project to use geothermal energy to chill water for cooling - Digging deep for future power.

While geothermal power has been used since pre-Roman times for warming and bathing, the use of the technology is just starting to heat up in Western Australia.

Since 2004, Challenge Stadium in the Perth suburb of Mt Claremont has used geothermal technology to heat its swimming pools. The stadium uses a geothermal supply about 700 to 1000 metres below the ground.

Now, one Perth company plans to take the concept a whole lot further, or deeper, and use the energy for cooling.

Richard Beresford is GreenRock Energy's managing director and says the geothermal energy below the city of Perth is potentially a huge resource. "We're planning on drilling deeper than has currently been drilled in the metropolitan area to get higher temperatures, around 3,000 metres."

In the process, water is pumped below the earth's surface, and when it returns it's very hot. If the temperature is high enough, the heat energy can be transferred into electricity and the water is recycled back into the ground.

The company has teamed up with the Geothermal Centre of Excellence at the University of WA.

Mr Beresford says the temperature of the water in the UWA project will not be hot enough to produce electricity but he believes it will be sufficient to drive technology called an absorption chiller, which produces cold water.

"The absorption chiller is not new technology, but it is relatively new to think about using geothermal energy as the heat source for them. That chilled water at UWA would then be circulated into their existing system which goes around the campus feeding the various air conditioning units."

Technology Review has an article on energy efficient air conditioning - An Energy-Saving Air Conditioner.

Keeping air cool in homes and offices this summer will be expensive--about 5 percent of the energy used in the United States each year goes to running air conditioners. But researchers at the U.S. National Renewable Energy Laboratory (NREL) in Golden, CO, have come up with a new air-conditioner design that they say will dramatically increase efficiency and eliminate gases that contribute to global warming.

"The technology we have today is nearly a hundred years old," says Eric Kozubal, a senior engineer at NREL. Kozubal and colleagues have come up with an air conditioner that combines evaporative cooling with a water-absorbing material to provide cool, dry air while using up to 90 percent less energy. The desiccant-enhanced evaporative, or DEVap, air conditioner is meant to addresses the old complaint, "It's not the heat; it's the humidity," more efficiently. ...

The industry is working on a variety of methods to improve the efficiency of air conditioning, Jacobi says, from the use of heat exchangers to improvements in the compression systems of traditional machines. "It's an area of great importance to the nation, because about a third of our nation's energy use is in buildings."

The U.S. uses about 100 quadrillion British Thermal Units each year, according to the U.S. Energy Information Administration. Up to 40 percent of that is used in buildings, with about 5 percent going to air conditioning. Kozubal says his system could cut that in half in less-humid areas and by up to 90 percent where humidity is high. "When you talk about a technology that can save 2 to 3 percent of the nation's entire energy supply, that's quite a lot," he says.

The desiccant used in the system is relatively harmless (calcium chloride is used in road salt), though its corrosiveness requires that metal be eliminated from the hardware. What's particularly attractive is that it replaces the chlorofluorocarbons that are used as the refrigerant in traditional air conditioners. Those CFCs can easily leak, and every kilogram of them provides the same greenhouse gas effect as about 2,000 kilograms of carbon dioxide.

Kozubal says it might take about five years to develop the system to a point where NREL can hand it off to industry for commercialization. The system is designed to replace existing systems without many changes, so it could be phased in as people upgrade their old air conditioners.

The desiccant can be reused simply by heating it up to boil off the water it's absorbed. In an industrial setting, that might be done using waste heat from another industrial process. In the home, natural gas or solar energy would work. In fact, Kozubal says, the setup could make solar thermal energy systems, which absorb sunlight to heat a home and its water, more cost effective. During hot summer days, solar energy that might otherwise go to waste could therefore actually help keep a building cool.

Renewable Energy World has an article on using solar thermal energy for air conditioning - Chilling Out in the Sun: Solar Cooling.

Worldwide energy consumption for cooling and air-conditioning is rising rapidly and the market potential for solar thermal cooling is certainly very large indeed. However, the market is still very much a work in progress – with only around 500 solar cooling systems installed globally – and has been largely dominated by Europe so far. David Appleyard takes a look at some of the key players in this emerging renewable energy sector.

During the last few years, especially in Europe, various new sorption chillers with small- and medium-scale cooling capacity have been developed. Many of these absorption and adsorption chillers have now passed from prototype and pre-commercial installations into small serial production and consequently a rising number of products are expected to enter the market in the coming years.

Despite a growing interest, the market has nonetheless been slow to develop with accepted figures pointing to German leadership of the European market with close to 40% up until 2004, followed by Spain with more than 27% of the European market. Indeed, by 2008, a total of only 450 to 500 solar cooling systems had been realized worldwide, the vast majority of which are in Europe, where the market has increased in the last five years by 50%–100% annually. Approximately 60% of these systems using absorption chillers, 11% adsorption chillers and 29% open systems (DEC and liquid sorption systems). Even so, the total volume of installations reveals that the solar cooling sector is still a niche market and effectively under starters orders.