CONCENTRATING ON ROOFTOP SUN

Rooftop CSP: Greening the cities
Rajesh Chahabara (w/Rikki Stancich), 11 February 2010 (CSP Today)

"…With buildings accounting for some 74 percent of electricity use in the United States, it is hardly surprising that energy efficiency and use of renewable energy have become key criteria in green building certification standards such as US Green Building Council’s LEED certification and UK’s BREEAM certification…As a relatively new product to market, micro CSP opens up new opportunities for buildings – green or otherwise - to efficiently generate on-site renewable energy.

"A portable and scalable on-site solar energy solution, micro CSP can be used to generate electricity, as well as to provide heating and cooling. Suitable for generating energy in the range of 75 KW to 20 MW, micro CSP’s size means the system can be installed in a small area - including on the rooftop of a building…Sopogy Inc.. has developed a range of micro CSP solutions…[that use] an organic ranking cycle (ORC), which instead of using steam, uses the temperature difference between fluids in a closed loop. Unlike large-scale CSP, which requires desert-like conditions of perfect direct normal irradiation, Sopogy’s micro CSP can operate in or near cities…"

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"France-based technology developer, heat2power, has come up with its own version of micro CSP, which uses CSP to power traditional cylinder engines…The concept is similar to that of a standard combustion engine, except the engine is powered by compressed air, using an external heat source (air heated on a solar receiver to around 900 - 1200°C) rather than from fuel creating an internal combustion…[T]he heat2power model is scalable…[generates] power from 10KW – 5MW…[and] does not require cooling towers or expensive dry cooling used for condensing steam…

"Micro CSP can help take green building standards to the next level, given that the system reduces the use of fossil fuel to heat, cool and power buildings…Currently, LEED and other green certification systems do not require specific renewable technology, nor do they standardise energy systems…[M]icro CSP promises to significantly help builders achieve points for certification…LEED certification currently allows up to seven points for on-site renewable energy, out of the total 110 points possible…"

If it's hot enough to need air conditioning, there's probably sun enough to use micro CSP to power it. (click to enlarge)

"…[W]hile PV technology may be good for meeting 5-10 percent of a large building’s energy needs, micro CSP on the rooftop can provide 30-40 percent of the energy needed…[and has a] shorter [3-to-7 year] payback period…Compared to other small-scale renewable energy options, micro CSP is a more efficient and, given its capacity for storage, a more stable option…

"Support policies such as feed-in tariffs will play an important role in increasing the market penetration of distributed generation systems such as micro CSP…The UK government recently introduced a feed-in tariff scheme…Such policies, if adopted elsewhere, will undoubtedly boost renewable micro-generation technologies such as micro-CSP…Increasing demand for green buildings from sustainability-committed multinational companies will also expand the number of micro CSP installations…[but industry insiders estimate] it will take about five years before micro CSP becomes commonplace in buildings…"