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Bill Gates venture backs effort to bring aircon startup to market

Supports liquid desiccant tech to store energy to smooth bumps in demand, lower greenhouse gas impact

A fund founded by Bill Gates is leading a $20 million investment round into an aircon startup which promises to slash the carbon impact of keeping people cool on a heating planet.

The cash is designed to get to market aircon units from Blue Frontier, which bases its approach on removing moisture from the air and doing the most work when electricity is cheap and more likely green at source. The company claims to reduce the greenhouse gas emissions from aircon by 85 per cent.

Gates' Breakthrough Energy Ventures is joined by 2150 Urban Tech Sustainability Fund and VoLo Earth Ventures in investing in Modern Niagara, the commercialization partner backing Blue Frontier in the hopes of bringing the technology to market.

The problems of aircon in terms of climate change are two-fold. Not only is the electricity needed for air cooling a major source of carbon emissions – as much as 4 percent according to some measures – as carbon emissions warm the planet, but at the same time, more people also require aircon and installed aircon is worked harder, more often.

To try to crack this spiralling impact, Blue Frontier has developed a technology which relies on liquid desiccants – substances which remove moisture from the air. The air is subsequently cooled by indirect evaporative cooling.

The first step in the Blue Frontier process is to concentrate its proprietary liquid desiccants in a salt solution, so it is available to produce air conditioning, a process also known as regeneration. Heat is used to concentrate the liquid desiccant, releasing water [PDF] that is recovered for later use to drive air conditioning.

Crucially, after the regeneration stage, the solution is available to cool air at any point afterwards. In this way, it is designed to store "potential cooling" and thereby take advantage of cheap green electricity and avoid using costly, more carbon-intensive electricity when demand is higher. It may also help avoid brown-outs which have become worryingly common in the hot Californian summers.

The system does rely on refrigerants and compression in the same way as conventional aircon and refrigeration, but they come into play in a different step in the process. Blue Frontier uses refrigerants in a heat pump to regulate salt concentrations in the desiccant. Because they are housed within the system, engineers were free to safely select mildly flammable refrigerants. It requires less refrigerant than a conventional system, and the refrigerant it uses has a lower impact on greenhouse gas emissions, the company says.

"The refrigerant and refrigerant-carrying equipment never meets air entering the building or the interior of the building," Betts told CNBC. "This gives us an enormous advantage to use readily available refrigerants that are mildly flammable, without putting at risk the safety of the people in the building."

The combination of greater efficiency, an ability to smooth out demand on the grid and the use of less impactful refrigerants creates a combined reduction in greenhouse gas emissions of between 85 and 87 percent, the company estimates.

Betts said the first products for commercial buildings will be available in 2025, following rollout to a few pilot sites. ®

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