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Why New Daedalus?

Daedalus was the mythical great architect and artificer of the classical world. Today, embedded intelligence is enabling the most profound changes in the way we create and use buildings since his day.

Building Intelligence meets the Intelligent Building. The Intelligent Building negotiates with the Intelligent Grid. How will this transform how we interact with the physical world?

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Thursday
Sep202007

Energy Storage at the Home and Office

Energy Storage is always the shoal upon which new energy use pattern run aground. Energy storage is what can disconnect us from the increasingly fragile grid. Energy storage would let the nation’s transmission lines work around the clock, increasing their capacity server fold.

Energy storage is what will make local generation deliver honest pay-back. Energy storage is what will align sunny day-time generation with home occupancy at night. Energy storage will let the home and factory trade freely in power markets.

Energy storage is so important, we have given it a pet name. We call it “The Hydrogen Economy”. But an actual hydrogen economy, like actual commercial fusion reactors is always, it seems, a decade or two away.

The shimmering vision of the hydrogen economy blinds us to how close the real solutions are. We have numerous ways to store energy today, from electrochemical to thermal mass, from raised ponds to bathtubs in the attic. We even have, well, old fashioned Hydrogen, good enough to work in the home, if not the car. Let’s call these amazing technologies batteries.

The battery economy won’t get its name on the cover of any magazines, but it’s the right place to watch. New kinds of batteries may come out of the places we are not looking. Peter Drucker once wrote that a new technology must provide a factor of 10 improvement in cost over the old to overcome the economic infrastructure supporting the old. Small improvements in existing batteries and simple rethinking of existing processes may always stay ahead of Hydrogen.

So where might we look?

Battery efficiency is properly understood not from anode to cathode, but from battery input through the device powered. Home and office DC power distribution can improve the practical efficiency of any battery by removing a round trip between DC (battery) to AC (to the plug) to DC (to supply today’s electronic devices). Improving the effective performance of a battery by 30-50% makes many technologies more viable.

Information technology is making long known methods to transform energy into suddenly new approaches. Stirling engines, for example, are a Victorian-era oddity that has amused generations of high school physics classes. Place one in your hand and the rotor spins – using the temperature difference between your hand and the room. Stirling engines are now coming into their own. Stirling Energy Systems has recently added a very large solar–based system to the western power grid. A commercially available home system recaptures waste heat from domestic hot water and space heating and generates electricity – and it can work on temperature differentials of as little as 15 degrees.

This makes thermal capture and storage an exciting part of the electrical mix. I can capture heat now to generate electricity now or later. I can store the electricity I generate for use now or later.

We may develop completely new approaches to thermal storage. One large solar facility in Spain uses mirrors to focus light and get temperatures high enough for generating electricity using traditional steam. This technology was made possible with embedded intelligence that allows a mirror array to constantly adjust to the current sunlight. Excess heat is stored by melting salt; the high heat molten salt is used to generate power later. Can this approach be scaled to the home or office? The most critical element is the software, which costs little to reproduce.

When we combine on site generation and distribution and use, it is called a microgrid. Microgrids become many times more reliable and economical with even a little on-site storage.

The home and office of the future will have its own microgrid with storage. A software agent will operate the microgrid while negotiating with the building systems to manage energy use. The agent will listen to the power grid to get up-to-the-second energy prices. The agent will be under the control of the building owners and occupants, responding to their wishes rather than to the wishes of the power company.

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