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

Chapter Fifteen: End-Use Efficiency: Most Resilience Per Dollar 251comfort (say fifty-five or sixty degrees in cold weather) could go right throughthe Canadian winter without even realizing there was no heating system.With slightly more windows on the sunny side of the house, the temperaturewould stay in the range of sixty-five to seventy-five degrees with no auxiliaryheating at all. And whatever else happened, a spell of unusually cold orcloudy weather would be unlikely to last long enough even to cause discomfortif the heating system failed.This behavior illustrates both the stretched time constant of the house—everythinghappens in slow motion—and its inherent limitation of extreme behavior. Anyproperly built passive solar house cannot get below fifty-odd degreesFahrenheit, no matter what. Even a badly built passive solar greenhouse, providedit has a reasonable amount of thermal mass (rocks, masonry, drums ofwater, etc.) for overnight heat storage, will never get below freezing in aMinnesota winter. So robust are insulated passive solar buildings that whenvandals broke down the door of one in Massachusetts, leaving a hole of severalsquare yards during the coldest night of the winter, the interior temperaturestill stayed above sixty. That building did not even have movable insulationunder its glazing—a refinement which would have stretched its time constantfrom days to weeks.It is also noteworthy that the Saskatchewan house’s heat-storing watertank, in cooling off from its highest to its lowest temperature (a range of ninetyFahrenheit degrees), releases enough heat to meet the house’s averagespace-and water-heating load, with no heat input, for four weeks. That isequivalent to having in a normal house a tank containing about three thousandgallons of fuel oil. (The normal inventory of a heating-oil distributor isonly ten times that large.) 63 A gallon of the hot water stores less than one percentas much energy as a gallon of oil, but it serves about equally well in atight house because so much less energy is required to do the same task in thathouse than would be needed in an ordinary, sievelike house.A third important result of the Saskatchewan Conservation House’ssuperinsulation is that heat can only diffuse around inside the house—it canhardly get out. The inside of the house is in almost perfect convective andradiative equilibrium. Thus any point source of heat, such as one short sectionof uninsulated hot water pipe, can heat the whole house evenly without requiringany heat distribution system. In this way an Alaskan superinsulated houseis evenly heated by a tiny stove putting out a few hundred watts in one corner.Yet the house has uniform temperatures within about a degree even to its farthestcorner, separated by long, labyrinthine corridors. This means that if normalheating fails, a superinsulated house can be amply heated by any smallwoodburner, a camping stove, a small lantern, even junk mail burned in a