Sustainability Journal



January 2014 Issue (files are in PDF format)



Providing heat when the power fails The recent ice storm in the Toronto area left 300,000 homes and businesses without power, some for over a week's time. Thermal storage systems can avoid the loss of heating, cooling and domestic hot water in such events providing the heat is stored at the working temperatures. However, a small amount of power is still needed to operate the circulation pumps. The amount of power that is required is comparable to that needed by desktop computers so it could be supplied by standard UPS supplies. To cover the possibility that the power grid might be down for long periods of time it would be desirable to be prepared to recharge the UPS batteries periodically (e.g. on a daily basis), for example by using power from a car.

Operating exergy storage systems where solar heat is not available

There are cases in which it may not be practical to rely on a solar thermal source for providing the high temperature input for exergy storage systems. Examples are in Canada's far north, where the sun doesn't shine at all for much of the year, in northerly areas like Scotland and Scandinavia, and in locations that may be shaded or that lack sufficient collection area. There are a number of alternative high temperature energy sources that could be used in these cases.

Storing Exergy Report presented at KEGS (NRCan)

* The energy output from Ontario's run-of-the-river generators can be approximately doubled in cases where the capacity factor is determined by the supply/demand match
* The annual demand for the electricity output can be cut by one third (because it is no longer needed for heating, cooling and DHW)
* The GHG emissions for buildings and power generation can be eliminated altogether (with no need for extra insulation, heat recovery, etc)
* The cost of providing both heat and power for buildings can be drastically reduced
* The potential power output is very large (up to 36,000 MW(t) from eastern Ontario alone)

Wind powered exergy stores

Ontario wind turbines generate considerably more electricity in the winter than in the summer. That capability can be exploited to build exergy stores that do not rely on solar heat to heat their cores. The storage functions are the same as those previously described for run-of-the-river generators but they require more drive power during the winter. An example based on an existing wind turbine array shows how this can be done. If Ontario's existing wind turbines used this approach their combined output would be 13,800 MW (real MW, not faceplate MW).