Solar Power Minus the Light

An anonymous reader writes "Popular Science is running a story about a small company trying to take advantage of all the global warming hype. Matteran Energy uses 'thermal-collection technology to heat a synthetic fluid with a very low boiling point (around 58F), creating enough steam to drive a specially designed turbine. And although a fluid-circuit system converting heat into electricity is nothing new, Matterans innovative solution increases the systems efficiency to a point where small-scale applications make economic sense.' Notably, this comes during a record breaking heat wave here in the US. So has the day finally arrived where I can run my AC off of all that heat outdoors?"

Comments

Its still a heat engine

[15Bit]

Its a great idea, but it still looks like a heat engine to me and so is limited by the difference between hot (the solar collector) and cold (not mentioned in the article) parts of the cycle. Its an idea that resurfaces every few years (i remember reading when i was a kid about undersea power generation utilising the temp difference between surface and deep water), but no-one seems to be able to make it work commercially.

The problem is fundamental - thermodynamics defines the maximum efficiency to be eff=1-T(cold)/T(hot). Given that those temps are in Kelvin, not celcius, optimistic max efficiency for this system (ie assuming you can boil the water and have a glacier in your back garden for cooling) is about 26%. Solar cells are already near this, and more centralised forms of power generation are well above.