BY ROBERT M. DE CHAZAL, Inventor, CEO, SunDraco Power Inc.
History is repeating itself and the world is again moving towards an extinction event. During one such event in Precambrian times, the dominant lifeform emitted so much oxygen that the air and ultimately life’s course was forever altered. Human existence is part of that event’s legacy. Today, the world is on the verge of another such event and again the agent is a dominant lifeform, namely us. The change is in the air.
We can mitigate many of the effects of using fossil fuels, but we have no answer for the huge, accelerating feedback cycles we have kicked off at both the Poles. Warmer air means less ice; less ice means more warming. This will be our legacy.
The answer is not to abruptly stop burning fossil fuels. Our economic infrastructure prohibits it. Such a reaction would cause enormous and costly upheavals and displacements. On the other hand, if we move too slowly, we bequeath to our descendants disasters we can only imagine, but might have mitigated.
At SunDraco we are working toward a viable part of the solution, a solar energy system which uses large, inexpensive packed-beds of materials as storage devices whose heat can later be used to create electricity for anything from industrial processes all the way down to space heating.
Our storage comprises packed-beds, porous bodies of sand, pebbles, or cobbles which handle very high temperatures, tolerate high energy densities, and promise low costs per kW/hr. They are non-toxic and chemically stable. Their storage materials can be accessed locally, not mined or manufactured abroad. Packed-beds can vary in volume from a few cubic meters to many thousands and the very largest may only need backup in the event of the longest sunless stretches and rare weather events. Local, efficient and stable.
Our aim was to use concentrated solar power (CSP) to heat our storage to 850°C or more. Conventional CSP systems use thermal oils which are not suitable for packed-beds, and which boil at 390°C. So we had to invent the SunScoop, which uses a more appropriate fluid, namely air.
Conventional multi-megawatt CSP power plants have a single, centrally located storage and heat-engine complex which is impractical when using air as our SunScoop does. Our design uses independent, smaller storage versions or cells. Our application would comprise of as many cells as required, without limit allowing growth to be incremental and cost effective. Cells do not have to be physically connected; they can be spread about conveniently and because air is light, cells can be arrayed up hillsides. When the demand is low, only several cells in an application need to run their engines, and can do so at their highest efficiency, unlike a very large engine running at low speed and less efficiency.
Using modelling and computational fluid dynamics, we have worked our way through a succession of designs. SunScoop IV has an asymmetry suited to latitudes such as southern Alberta, where conventional CSP troughs are known to flag. Where our solution is a hybrid, having photovoltaic panels mounted along each SunScoop to take advantage of wasted sunlight. PV makes money while powering the heat collection process. Our latest design, SunScoop V, will go to lower latitudes and compete directly with conventional CSP plants in large markets such as the southern U.S., Spain, and S. Africa.
Our science tells us we have an efficient design, and our marketing tells us that Southern Alberta is our ideal start location. At first we will use SunScoops along with STORASOL storage units from our German partners, and off-the-shelf heat engines. Within several years we anticipate including our own large capacity units for longer-term storage.
We have come a long way since we began, thanks in large part to the like-minded people at Scovan Engineering. They have earned our deep gratitude for their generosity and understanding. They are a visionary, forward-looking group. But we still have a long way to go. Our search continues for partners who share our vision and who recognize our potential.
Originally published in Scovan’s IGNITE Vol. 4
