Brittle Power- PARTS 1-3 (+Notes) - Natural Capitalism Solutions

250National Energy SecurityMeeting this peak load would require either a large furnace or an installedelectrical generation, transmission, and distribution capacity costing about asmuch as the house itself. In contrast, the Saskatchewan Conservation Households in its heat so effectively that even with a temperature difference of ninety-nineFahrenheit degrees across its shell—seventy degrees inside compared tominus twenty-nine degrees outside—the interior temperature can be maintainedwith only three and seven-tenths kilowatts of total heat supply if theshutters are closed, or five and a half kilowatts if they are open. A small solarsystem, a very small stove, or many other types of heat sources can meet sucha modest need.Thus the superinsulation and the air-to-air heat exchanger have reducedthe space-heating load from a series of frequent huge peaks to a series of infrequentsmall blips, superimposed on a steady water-heating load. That waterheating“baseload” is indeed three times as big as the average space-heatingload for the whole house, even though the water-heating load has itself beenreduced by a third from its normal value through the recovery of heat fromgraywater. (Water-heating loads bigger than space-heating loads are a commonoperational definition of a superinsulated house.) It is because the spaceheatingpeaks are much less frequent and less intense—in duration and size—than they would normally be that the solar system can have such a small collectorarea and storage volume. But whether the house uses a solar system ornot (currently it does not), this moderation of the average and peak heatingrequirements clearly makes it vastly easier to keep the occupants comfortablein both normal and emergency conditions.Another reason for this inherent resilience is that although the house has“low thermal mass”—it can store heat only in its light frame construction—itsthermal “time constant” 62 is about one hundred hours, or about four times aslong as for a normal house of similar construction. The SaskatchewanConservation House stores no more heat than other frame houses, but losesit far more slowly; and for delaying the drop in temperature, this is exactlyequivalent.Thus, such a house provides inherent protection. In zero-degree weatherand in continuous total darkness, the house would take thirty-four hours to dropto fifty degrees Fahrenheit. Under the December conditions least favorable forpassive solar gain through the windows, the house would probably take severalweeks to get as low as fifty degrees, and temperatures much below thatwould be physically impossible unless the shell had somehow been seriously damaged.Thus if the house had no working furnace, baseboard heaters, cookingstoves, solar collector, pet, or any other external heat source, an occupant willingto tolerate an English rather than an affluent North American standard of