Resources It probably takes someone pretty familiar with na_tural cli-., mate design to separate the wh.eat from the chaff m Eko~e a publications. If you want g~n,e.ral information on th_e designs, go to the CQ and BH&G ar~icles. If you want to build.one of their designs, find out their: 'tot~l- charges.for ~ll parts of the services they provide.}f y<;>'u,want_to use the ideas-beg, borrow or xerox a copy of their publications or wait until someone distills it all into·an affordable and sensible form. "Don't Build a Hous·~ till Yoti'~e Looked at This," Micha~l Phillips, Co-Evol1f_tio-'[?_q _ua r:teri;;, Summer 1978, p. 100-102. "A Step Ahead in Solar Liyi~_g/ Cheryl Scott, Better Homes and Gardens, March 1979; p·: 50.~55. ' . ..,.,, "The Ekose'a House," Le~ Port-~r. Butler, Co-Evolution Quarterly, Winter 1978-79, p. 33:3.4, - Ekose'a Homes, 88 pp., $24.95, and The Energy Producing House, $18.95. Both from Ekose'a, 573 Mission St., San Francisco, CA 94105. ODO CRA'M..SAICi _ .MASS , Double.-Shelled Houses '·' • Phil Henshaw In my developing of a~ understandii:ig of the mfcro-structure of passive thermal events bu'ilt upon thousands of direct observations, I have yet to observe a warm air \urrent di·g·down through a co.ol air layer to rest in contact with a cooler surface below. This means, conclusively to.me, that no energy is ever transferred directly from air to ground, only the other direction. Yet the darned things work, in the situations so far considered, as if heat were transferred from air to ground. Because essential parts of the behavior description are strongly contradictory, aii'd because there is a feeling of "looseness" to it all where not every event is quite linked to each other, 'it seems to me that the actual energy pathways have probably never been mapped. So who cares if you 're using the wrong formula and somehow get the right answer? Anyone who wants real design and related freedom! My Double Shell Building sketch is of behaviors I would postulate to be found essential to the actual behavior of double shell houses. Notice the sleeve of earth temperature air which is pictured sliding up adjacent to the inner shell. That earth temperature air is what I suggest constitutes the important contact environment of the inner shell. The outer sleeve of colder than earth heat is shown slipping down to rest on and be warmed by the earth. Deep earth heat is shown welling up under the building by internal earth fluid circulation which necessarily exists (at some scale) because soil is permeable and the earth at a depth under the house is warmer than earth at the same depth around the house_. October 1979 RAIN Page 21 DOUBLE SHELL BUILDING -WINTER (ConceptuaI) Notice that no glazing of any sort is shown taking part in these cycles. A house in central New York (the Howells' house, a super-insulated ceiling wall and foundation house over a slab on grade with a vapor barrier and limited windows) during a week of O degree and clouds held a temperature never below deep earth temperatures of 47 degrees, with no internal gains. Though it would cool directly to 47 degrees, it would refuse to go below. It thus appeared to have the behavior of the Ekose'a air shell I'm suggesting. One interesting twist is that the Howells' s_lab on grade house design seems more appropriate for southern climates with warmer deep earth temperatures and the double shell more appropriate for northern climates with colder earth temperatures. This is just the opposite of where the two concepts were developed. Also of interest in this frame of things is that over-the-top air passage in the double shell house isn't neccssarr ~n~ that the air conduction to and from the earth for cond1t10mng the roof co~ld be boxed separately from the wall air space. Experiments with these and other arrangements wi~I be par~ of the substantive study needed to develop real design confidence with this approach. Solar gain might serve significantly in interrupting the use of earth heat by a sequence of s~eps ~esulting in cool air currents warmer than the earth and in being absorbed to linger in the large wood, or other, mass of the structure. If the bottom of the bottom floor were (a sample) ten degrees warmer than the earth all 24 hours of the day, then ~nergy equal to a full hour of bright sun a day would be transferred to the earth by heat radiation. For heat from around the circle air currents in the day to contribute the same it would have to be 30 degrees warmer (SO+ 30 = 80) and the underside not foil surfaced. Inviting large amounts of condensation anywhere in a construction is generally a hazard to be avoided or very specially allowed for. Also, design for. air currents can simult<j.neously be design for the Wdrst possible fire trap. Fire dampers can be simply installed if someone puts them in. So, where to from here? Somebody ought to study the darn things. Other than carefully observing air currents, anyone with access to a double shell, or otherwise earth couple house could check the fluctuations in the deep earth rcmpetature and how severe a climate condition causes it to fall below. Pay special attention to how long it holds what temperature. We'll all be listening to hear what you find. ODO
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