CA2841018A1 - Efficient house: an efficient, healthful and durable building system using differential airflow and heat control across an air permeable heat reflective external envelope assembly - Google Patents

Abstract

An efficient building design uses airflow across dynamic exterior walls to counteract heat transfer thereacross. The dynamic walls feature a stud wall layer with air- permeable wall insulation in the stud cavities, an air-permeable external insulation layer with rigid insulation panels, a building wrap layer, and heat reflecting material arranged to reflect radiant heat back away from the wall in both directions. Monitoring and control systems monitor conditions associated the dynamic wails and control airflow therethrough in response to the monitored conditions. The control system is switchable between a heating mode, in which the the dynamic walls are depressurized to draw air into an air distribution system from the external environment, and a cooling mode in which inside air from a lower level of the building's interior space enters the dynamic wall structures through the air distribution system and is forced out of the building through the dynamic walls.

Description

EFFICIENT HOUSE: AN EFFICIENT, HEALTHFUL AND DURABLE BUILDING SYSTEM
USING DIFFERENTIAL AIRFLOW AND HEAT CONTROL ACROSS AN AIR PERMEABLE
HEAT REFLECTIVE EXTERNAL ENVELOPE ASSEMBLY
FIELD OF THE INVENTION
This efficient house invention relates generally to buildings using differential flow of air through air-permeable exterior walls and ceilings that also incorporate a reflective material, to capture, reflect, and control heat being transferred through the envelope, to improve energy conservation, durability of the structure, and provide fresh air to such a building.
BACKGROUND OF THE INVENTION
Control of heat losses and gains in houses has been attempted from the time of earliest shelter. Today's buildings are 'tight (reducing air leakage) and well-insulated (reducing heat losses and gains) but relatively inefficient, unstable and unhealthy. For example, costly special mechanical devices such as heat recovery ventilators (HRVs) are needed to supply tempered fresh air for indoor air quality to reduce the risk of unsafe indoor conditions, and these often break down or perform poorly during their lifetime. Also air tight designs promote mold and mildew when humidity levels become high and contamination occurs when pollutants are not sufficiently diluted (Forest 2004). Structural deterioration and mold and mildew are common problems that occur when moisture becomes trapped, and normal fiber insulation becomes ineffective as humidly levels within insulated assemblies (e.g. exterior wall cavities) become elevated (Swinton, Brown and Chown,1995) .
For about 30 years it has been known that fresh 'dynamic air' moving slowly inwards through the envelope (e.g. exterior walls) of buildings could recover conductive heat normally lost in the heating season and provide the fresh air required for healthful indoor air quality. Beginning in the late1970s, experimental houses were constructed in Sweden using the idea and a 'depressurization of the house' approach. In the 1980s experimental houses using a similar approach were constructed in Canada, under the guidance of Dr. John Timusk, one constructed in Ontario in 1981 and 1982, and two in Alberta between 1983 and 1987, funded by Alberta's Innovative Housing Grants Program. Reports of these early experimental houses are in the public record (e.g., Thoren 1982; Anderlind and Johansson 1983; Levon 1986; Timusk 1987; and Mackay 1990).
However, with the price of oil remaining low though the 1980s, interest waned and there appears to have been a general lack of interest and lack of development from 1987 to recently, when the idea was picked up by two groups: one from Lakehead University, Canada and the other from University of Aberdeen, Scotland. Each has taken a different approach to the basic idea, the former goes back to first principles of engineering physics to develop a new SUBSTITUTE SHEET (RULE 26)

2 approach using existing materials in novel ways and the latter focuses on a composite panel.
One reason for the apparent period of inactivity is, despite the potential of the idea, results from early houses were disappointing, with much less than predicted heat recovery and insufficient fresh air supply. Besides air quality concerns, heat recovery was only approximately 50% of the predicted value with high incremental costs. The 1986 Report T5 of the Swedish Building Council concluded that "... the energy goals were not satisfied" (as quoted in Timusk, 1987 p.

3). Although air quality was improved over existing houses, the fresh air supply proved insufficient to satisfy Canadian building code requirements and needed to be supplemented.
This could be done by using heat recovery ventilator appliances, but added to cost of construction and introduced other problems including failure of most of these appliances to operate properly within a few years of installation.
Timusk later had come to the conclusion that depressurizing the wall cavities made more sense than depressurizing the building from both an energy conservation and air quality standpoint, and he relayed this information to those interested, for example Timusk sent a sketch of this idea to Dr Bryan Poulin of Lakehead University, who shared this idea with Dr.
Tony Gillies. Since then, Bryan Poulin and Dr. Tony Gillies have explored and extended this and other ideas and, building on their own experience, invented the efficient house system that they laboratory and field tested, together with the assistance of students and the Innovation Office of Lakehead University, on a confidential basis.
The apparent lack of development from 1987 to date in efficient housing suitable for the North may have been due to a combination of factors that included lack of interest in energy conservation because of relatively low energy prices, less than optimal performance due to technical difficulties that were not resolved, and no serious commercialization effort due to the right team not being assembled. Reasons for the disappointing results of previous attempts to harness the idea may have been a combination of wrong approach (depressurizing the house to pull in the fresh air), uncontrolled air infiltration (at doors and windows and between assemblies), thermal bridging (e.g., heat conducting through the solid wood assemblies) and inadequate and impractical inventions, including overly complex and/or fault prone devices to supplement fresh air requirements (e.g., heat recovery ventilator units) (DeProphetis 2006).
Besides technical problems, there may have been other problems with the innovation process, including inadequate testing of prototypes to find out what worked well and what did not, and inadequate commercialization effort. For example, reflective coatings are commonly used to reflect radiant heat for windows but not exterior walls.
Technology and commercialization problems encountered, in early attempts at using the idea, appear not to SUBSTITUTE SHEET (RULE 26)

4 have been adequately addressed by any inventions to date, each having been piecemeal while it appears that a comprehensive and systematic approach was required.
Recently Brown, lmbabi, Murphy and Peacock (2008) discuss a "dynamic breathing building" in similar terms although the present invention contains unique features found in no other system including that of Brown, lmbabi, Murphy and Peacock.
These unique features include the differential handling of air drawn through exterior walls and ceiling, and the special control system to handle the collection and distribution of fresh air.
Also the current invention uses or adapts existing materials for the exterior wall and ceiling assemblies, unlike the proprietary wall panel described by the Brown lmbabi, Murphy and Peacock approach. In addition, refinements suggested by the testing of the current invention and its various components in the Lakehead University bike shack and testing from 2006 to 2010, including the specific testing of certain aspects such as the efficacy of the reflective material applied to the exterior envelope, make the entire system uniquely suitable for building conditions in Northern Canada and similar climatic conditions elsewhere.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided an efficient building using airflow across one or more exterior walls to counteract heat transfer thereacross, said one or more exterior walls each having a dynamic wall structure comprising:
a stud wall layer comprising a series of wall studs spaced along a length of the wall structure with stud cavities between adjacent studs and air-permeable wall insulation material disposed within the stud cavities;
an air-permeable external insulation layer comprising rigid insulation panels fixed to the wall stud layer on an exterior side thereof facing outwardly away from an interior space of the building toward an external environment outside the building;
a building wrap layer disposed on an exterior side of the rigid air-permeable insulation panels facing away from the wall studs; and heat reflecting material arranged within the wall structure to reflect radiant heat back away from the wall in both directions.
According to another aspect of the invention there is provided an efficient building comprising:
a plurality of exterior dynamic wall structures surrounding an interior space of the building, the dynamic wall structures being air permeable to allow airflow therethrough from an external environment outside the building;
SUBSTITUTE SHEET (RULE 26) at least one depressurization source fluidly communicated with internal spaces of the dynamic wall structures and operable to depressurize the internal spaces of the dynamic wall structures relative to the external environment to induce the airflow through the dynamic wall structure from the external environment; and a monitoring system configured to monitor conditions associated with each of the exterior dynamic wall structures;
a control system linked to the monitoring system and configured to control the depressurization of the internal space of each dynamic wall structure in order to control airflow through each dynamic wall structure in response to measured values of the monitored conditions.
According to yet another aspect of the invention there is provided a sheathing panel for an air permeable wall assembly, the sheathing panel comprising:
a sheathing panel body having a length, a width and a thickness defining two opposite ends, two opposite sides and two opposite faces of the body;
a plurality of holes formed in the sheathing panel body to extend fully therethrough from one of the two opposite faces to the other; and a plurality of hollow inserts received in respective ones of the plurality of holes, each hollow insert being hollow between opposite open ends thereof and having an outer size and shape arranged to fit against the sheathing panel body at the perimeter of the respective hole to reinforce an open condition thereof between the opposite faces of the sheathing panel body.
According to a further aspect of the invention there is provided an efficient building comprising:
a plurality of exterior dynamic wall structures surrounding an interior space of the building, the dynamic wall structures being air permeable at exteriors thereof to allow airflow between internal spaces of the dynamic wall structures and an external environment outside the building;
at least one depressurization source fluidly communicated with internal spaces of the dynamic wall structures and operable to depressurize the internal spaces of the dynamic wall structures relative to the external environment to induce the airflow through the dynamic wall structure from the external environment; and an air distribution system coupled to the dynamic wall structures to fluidly communicate with the internal spaces thereof, the air distribution system having at least one discharge that opens into the interior space of the building; and a control system switchable between a heating mode, in which the internal space of at least one of the dynamic wall structures is depressurized to draw air into the air distribution SUBSTITUTE SHEET (RULE 26) system from the external environment through the dynamic wall structure for release into the interior space of the building via the discharge, and a cooling mode in which inside air from a lower level of the building's interior space enters the dynamic wall structures through the air distribution system and is forced out of the building through the dynamic wall structures.

5 BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate exemplary embodiments of the present invention, Figure 1A is a schematic sectional view of an efficient house according to a first embodiment of the present invention operating during the heating season, and illustrates how the three mechanisms of heat gain are optimally treated.
Figure 1B is a schematic sectional view of an efficient house according to a first embodiment of the present invention operating during the cooling season.
Figures 2A and 2B are schematic close up sectional views of a portion of the efficient house of Figures 1A and IB, marked as Detail 1 in Figure 1A, and illustrate alternate ceiling and exterior wall structure details as exterior air flows through the structure in the heating season.
Figure 3 is a schematic illustration of an inlet/distribution chamber of an air distribution system of the efficient house of Figure 1A.
Figure 4 is a schematic illustration of the exhaust heat recovery unit or heat exchanger connected between the air distribution system and an exhaust air collector of the efficient house of Figure 1A.
Figure 5 is a schematic illustration of a control system of the efficient house of Figure 1A.
Figure 6 is a schematic overhead view of an efficient building according to a second embodiment of the present invention in a demonstration building constructed and tested at Lakehead University.
Figure 7 is a partial schematic sectional view of the efficient building of Figure 6, illustrating ceiling and exterior wall structure thereof.
Figure 8 is a schematic face view of a sheathing panel used in the wall structure of Figure 7 and Figure 8.
Figure 9A is a schematic illustration demonstrating operation of an alternate embodiment control system for the efficient house of Figure 1 in a default night-time mode of operation.
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6 Figure 9B is a schematic illustration demonstrating operation of the alternate embodiment control system in a daytime a.m. or morning mode of operation.
Figure 90 is a schematic illustration demonstrating operation of the alternate embodiment control system in a daytime p.m. or afternoon-evening mode of operation.
Figure 9D is a schematic illustration demonstrating operation of the alternate embodiment control system in a daytime peak mode of operation.
DETAILED DESCRIPTION
Figure 1A shows an efficient house 1 having four exterior side walls with a ceiling disposed thereover to enclose an interior space 2 of the house over a foundation thereof. An attic space 4 is defined between the ceiling structure 6 and a roof structure 8 disposed thereover with a floor/ceiling structure 10 dividing the interior space 2 of the house 1 into an upper level 2A and a lower level 2B. Each exterior side wall structure 12, two oppositely facing ones of which can be seen in cross-section in each of Figures 1A and 1B, is air permeable at the exterior face thereof exposed to the outside environment surrounding the house 1 and has a hollow airspace 14 defined within it as illustrated in Figure 2A. On the interior side of the wall structure 12, the hollow airspace 14 defined therein is in fluid communication with ductwork 16 that is closed off from the surrounding interior space 2 of the house and connects to an air distribution system 18 in the lower level, or basement, 2B of the house 1. Alternately outside air is drawn through the exterior insulated stud wall cavity directly to the ductwork 16 without the hollow airspace 14 as illustrated in Figure 2B. The air distribution system includes an inlet/distribution chamber 20 that establishes the connection to the ductwork 16 and also connects to a conditioning unit 22, which in turn feeds a discharge 24 that finally releases the airflow through the distribution system 18 into the interior space 2 of the house 1.
When operated during the heating season, or winter, a heating fan within the conditioning unit 22 is operated to draw air into the distribution system 18, defined in part thereby, through the ductwork 16 from the hollow airspace 14 within each of the exterior side walls 12.
This depressurizes the airspace 14 relative to the outside environment so as to draw fresh outside into the airspace 14 through the air permeable exterior side of the wall structure 12. The fan further draws the air through the ductwork 16 into the inlet/distribution chamber 20 of the air distribution system 18 and onward into the conditioning unit 22, which in the first embodiment includes a heating device, such as a furnace or heat pump. Fresh air thus enters through walls and ceiling and is carried by ducts as shown, such that the fresh outside air is drawn into the conditioning unit 22 without any substantial mixing with the air of the interior space 2 of the house, due to the closed nature of the ductwork except for its communication with the distribution SUBSTITUTE SHEET (RULE 26)

7 system 18 at the inlet/distribution chamber 20 thereof, and is warmed by the heating device for subsequent release of this heated outside air into the interior space 2 through the discharge portion 24 of the distribution system 18. The conditioning unit 22 may be further equipped with a filter to filter outside air drawn into the distribution system prior to release into the interior space 2 of the house 1.
During the inward flow of air described in the preceding paragraph, the outside air is warmed or preheated as it as it is drawn into the depressurized airspace 14 within the wall structure 12 by outward flowing heat that otherwise would be lost to the outside environment from the heated interior 2 of the house 1 by transfer through a conventional wall structure. The sealing off, as much as possible, of the interconnected hollow airspaces 14 within the walls, ductwork 16 connected thereto and distribution system receiving air therefrom from the interior space 2 of the house means that only the hollow airspaces 14 need to be depressurized relative to the outside environment surrounding the house 1 to draw fresh outside air into the house.
In other words, the provision of an air permeable wall assembly depressurized by a central fan avoids the need to depressurize the entire house to draw air thereinto. Furthermore, with the airspace depressurized below both the air pressure outside and inside the house, any leakage at the interior finish of the exterior walls 12 that in a conventional building structure would potentially allow leakage of warm air from the interior space 2 of the house instead just feeds back into the heating system through the ductwork 16 from the airspace 14 it has leaked into along with the inward flow of fresh outside air.
As shown in Figure 1A, the ceiling structure 6 defining, with the exterior side walls 12, part of the envelope enclosing the interior space 2 of the house 1, is also taken advantage of as a site for recovering heat that would otherwise simply be allowed to escape into the attic space 4, as the ceiling structure 6 also includes a respective hollow airspace 14C
therein that is fluidly connected to the ductwork 16. The attic space 4 is ventilated in a known manner, for example by soffit ventilation between the exterior side of the exterior side walls and the outer edges or eaves of the roof 8, so that outside air entering the attic space 4 is drawn into the ceiling airspace 14C 6 by the depressurization thereof by operation of the conditioning unit heating fan to draw air from the hollow airspace 14 through the ductwork 16. The fresh outside air entering the ceiling airspace 14C thus absorbs heat transferring outward from the heated interior space 2 through the ceiling structure 6. With this heat recovery occurring differentially at all walls exposed to the air of the outside environment, i.e. each exterior side wall 12 and the ceiling structure 6, heat loss or waste is significantly reduced relative to conventional housing construction.
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8 In the illustrate embodiment, the aforementioned hollow airspace 14 within each of the external side walls 12 is disposed entirely within an elevation range corresponding to the upper level 2A of the house's interior space 2 above the floor/ceiling structure 10 dividing the two levels. A separate and additional lower level or basement hollow airspace 14B
is defined within each exterior side wall 12 within an elevation range defined below the floor ceiling structure.
These additional lower level hollow airspaces 14B are connected to the distribution system 18 by additional ductwork 16B to draw fresh outside air thereinto in the same manner, so as to pick up heat that would otherwise be lost through the lower level portions of the external walls during the heat season.
During the above-described operation of the heating system during the heating season to draw in fresh outside air while picking up waste heat that would otherwise be dissipated from the house by heat loss through the exterior side walls 12 and ceiling 6, the outside air being drawn into the distribution system 18 by operation of the heating fan in the conditioning unit 22 flows through one fluid-path of a two-stream heat exchanger 26 on its way from the inlet/distribution chamber, or IDC, 20 to the conditioning unit 22.
The other fluid path of the two-stream heat exchanger 26 is fed by an exhaust air collection system 28, that at an inlet end 28A on one side of the heat exchanger 26 receives exhaust air from a kitchen or bathroom, for example under operation of a bathroom exhaust fan or kitchen exhaust hood, and at the discharge or exhaust end 28B on the opposite side of the heat exchanger discharges to the outside environment. So connected between the exhaust air collector 28 and the air distribution system 18, the heat exchanger facilitates heat transfer from exhaust air, that is typically discharged straight to the outside environment without any heat recovery in a conventional housing structure running an exhaust fan, to the outside air being drawn into the conditioning unit 22 by the heating fan thereof. Not only does this use of the heat exchanger as an exhaust heat recovery unit, or EHRU, improve on conventional exhaust systems where heat, such as that developed during running of a hot shower in the bathroom or cooking in the kitchen, is simply wasted during direct exhaust to the outside environment, but it also improves on prior art heat recovery systems by using the heat being discharged from the interior space of the house 2 through the exterior side walls 12 and ceiling 6 to preheat the outside air being drawn into the house and defining the heat exchanger's cold stream. Having the outside air warmed during its passage inward through the walls before entering the heat exchanger reduces or eliminates dependency on a defrost cycle to ensure proper and efficient operation of the heat exchanger and less probability of breakdown. An alternative is to eliminate the heat exchanger, where there is very high cost of maintenance and service, for example in the far North of Canada.
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9 Having been warmed during passage through the walls externally exposed to the outside air, including the ceiling, and subsequently flowing through the heat exchanger 26, the outside air is further heated in the conditioning unit 22, for example by a furnace or heat pump or electric coil thereof, and finally released into at least one area of the interior space 2 of the house through a discharge portion 24 of the distribution system, for example through conventional duct and register arrangements such as those commonly used in conventional forced-air heating systems. Heat loss to the outside environment during the heating season is greatly reduced relative conventional housing structures, not merely by trying to block or slow heat transfer outward through the walls but by instead by making use of such heat transfer, which typically amounts to wasted heat, along with heat typically discharged directly to the outside environment by exhaust systems, to warm an incoming supply of fresh outside air.
Reflective properties of the Delta Dry, if used, or separate reflective materials within the exterior facing walls and ceiling will reflect heat back into and away from the interior of the building.
As shown in Figure 1B, the operation of the system can be reversed from that shown in Figure 1A to run in a cooling mode in the cooling season. An air intake conduit 30 extends through at least one of the exterior side walls 12 to communicate the interior space 2 of the house 1 directly with the outside environment when one or more dampers 30A
are opened during the cooling season. The conditioning unit 22 in the lower level 2B of the house 1 features an inlet 22A through which air is drawn into the conditioning 22 during operation of a cooling fan thereof. This cooling fan and the heating fan used during the heating season may be defined by the same fan unit, operable to rotate in opposite directions to effect the necessary air flow direction through the distribution system depending on whether heating or cooling of the interior space 2 is required. During the cooling mode operation, a damper 32 closes off the connection between the heat exchanger 26 and the conditioning unit 22 while another damper 34 is opened to fluidly connect the conditioning unit 22 with the inlet/distribution chamber 20 of the air distribution system 18 and the ductwork 16, 16B connected thereto while bypassing the heat exchanger 26. Opposite to the heating fan, which operates to draw air into the conditioning unit 22 of the distribution system 18 through the inlet/distribution chamber 20 thereof from the ductwork 16 communicating with the hollow airspaces 14, 14C in the external side walls 12 and ceiling 6, the cooling fan draws air into the conditioning unit 22 through the inlet 22A thereof and forces it outward from the conditioning unit 22 into the ductwork 16, 16B
through the inlet/distribution chamber 20, but not by way of the heat exchanger due to the closed condition of damper 32. This airflow into the ductwork 16, 16B continues onward into the hollow airspaces 14, 14C communicating therewith and thus subsequently outward through the air permeable SUBSTITUTE SHEET (RULE 26) outer sides of the exterior side walls 12 and ceiling 6. Air flows from inside to outside through air permeable wall assembly, opposite the airflow created during heating mode operation. Since the outside environment is warmer than the interior space 2 of the house 1 in the cooling season, heat transfer through the walls is inward, opposite the direction of heat loss in the heating season.
5 The forced outward flow of air through the permeable wall and ceiling structures thus opposes this inward flow of heat, absorbing the heat and carrying it outward back to the outside environment, thereby reducing or preventing heat transfer into the interior space 2 of the house 1.
In addition to reducing heat transfer into the interior space 2 by carrying heat outward with out-flowing air, and reflective coated materials, the cooling mode operation of the

10 system also distributes cooler air from the lower level 2B of the house 1 into the upper level 2A, which will naturally tend to be warmer due to the higher buoyancy of warm air relative to that of cooler air. The forcing of cool air upward into the upper level 2A occurs by opening a damper 36 within at least one branch of the discharge arrangement 24 that discharges into the upper level 2A of the house 1. With this damper 36 open, air from the conditioning unit 22 is forced by the cooling fan, not only through the ductwork 16, 16B to the hollow airspaces 14, 14B, 14C in the exterior side walls 12 and ceiling 6, but also through this branch of the discharge arrangement 24.
Cool air from the lower level is thus not only forced outward through the air permeable wall structures, including the ceiling, to oppose heat transfer into the interior space 2 through these structures, but is also forced into the upper level 2A of the interior to provide a cooling effect.
Lower level air is thus distributed by fan, with this cooling mode operation also bringing fresh outside air into the house through the intake 30 for subsequent distribution once entering the conditioning unit 22 through the inlet 22A thereof.
During cooling mode operation, the heat exchanger 26 is inactive, unlike during heating mode operation. As shown in Figure 1B, in addition to closing the connection between the heat exchanger 26 and the conditioning unit 22 by way of damper 32 to close the cold stream path through the heat exchanger, the warm stream path may also be closed by closing dampers 37 at the exhaust or discharge end 28B of the exhaust air collector 28 and instead opening an alternate exhaust air discharge conduit 38 that releases exhaust air, for example from the kitchen or bathroom, directly to the outside environment without passage through the heat exchanger 26.
Alternatively, the envelope may transfer all the heat necessary for efficient operation, without the need for a separate heat exchanger.
Referring to Figure 2A, each exterior side wall 12 features, from inside to outside the house 1, an interior wall finish 40 (e.g. drywall), vapour barrier or retarder 42, the hollow air space 14, insulation 44 (e.g. fiberglass or rock wool insulation) within the cavities of the exterior SUBSTITUTE SHEET (RULE 26)

11 stud wall, air permeable sheathing/insulation 46 (e.g. insulating polystyrene sheathing equipped with holes to admit exterior air during the heating season) and an air-barrier/strapping/exterior-finish arrangement 48 or other rain-screen sub-system. In addition, the wall includes a reflective material within the wall (e.g. either a reflective coating at the exterior facing building wrap or a reflecting material within the cavity such as aluminum foil). The vapour barrier or retarder 42, is typically located under the interior finish of the wall at the interior side of the hollow airspace or cavity in the wall. An alternative installation 50, is shown on the other side of the hollow airspace 14 at the interior face of the insulated stud wall 44. A plenum 52 is supported at the interior face of the wall 12 with its hollow interior in fluid communication with the hollow airspace within the wall 12 via a series of openings 54 extending through the interior wall finish 40 at spaced positions therealong near the top of the wall 12. A stack effect can be expected to help draw air upwards through the exterior wall and this may allow sufficient air flow directly to duct without the need for the hollow wall cavity 14 behind the interior face of the exterior wall, as shown in Figure 2B. Operation of the heating fan during the heating season lowers pressure in the plenum 52 and wall cavity 14 to lower than outside and inside air to draw air from the outside environment into the hollow airspace 14 and collect any inside air leaking into the wall from the interior space 2. It will be appreciated that plenums may be incorporated into some walVceiling designs and eliminated as separate external structures.
The ceiling structure is similar in function, consisting of, from the interior space 2 of the house 1 outward, an interior finish 56, vapour barrier 58, the hollow ceiling airspace or plenum 14C, an air permeable membrane 60 and insulation 62, the ceiling's hollow airspace 14C opening into the ductwork through intentionally provided gaps, breaks or openings in the interior finish. As suggested by the solid-headed arrows in Figure 2, the outside air drawn into the hollow airspaces 14, 14C in the exterior side walls and ceiling 6 during heating mode operation is guided onto the inlet/distribution chamber 20 by the ductwork 16. As shown strapping 64 set perpendicularly crosswise to the ceiling joists may be used in a conventional manner for support of the ceiling's interior finish 56, with staggering of the strapping 64 in its lengthwise direction perpendicular to the floor joists providing gaps to allow for airflow within the hollow airspace 14C in which the strapping 64 is disposed, between the vapour barrier 58 and the air permeable membrane 60.
Figure 3 schematically illustrates the inlet/distribution chamber 20 of the air distribution system 18 during operation of the efficient house 1 in the heating season, as represented in Figure 1A. The ductwork 16, 16B connecting the hollow airspaces 14, 14C within the exterior side walls 12 and ceiling 6 includes ceiling branch 16C, north wall branch 16N, south wall branch 16S, east wall branch 16E and west wall branch 16W connected to the ceiling SUBSTITUTE SHEET (RULE 26)

12 structure 6 and north, south, east and west exterior side walls of the house 1 respectively. Each branch of the ductwork 16, 16B connects separately and distinctly to the inlet/distribution chamber 20 of the distribution system 18. The upper level ductwork 16 in the upper level 2A of the interior space 2 of the house 1 in Figures 1A and 1B thus actually represents five separate ducts each defining a sealed air path from a respective one of the four exterior side walls and ceiling of the house 1 to the inlet/distribution chamber 20 of the distribution system 18, carrying air from a respective one of the hollow airspaces 14, 140 to the inlet/distribution chamber 20 without mixing with air from another airspace or air from within other parts of the interior space 2 of the house 1. The lower level ductwork 16 in the lower level 2B of the interior space 2 of the house 1 is similarly four separate ducts each fluidly communicating in a sealed manner with the lower level hollow airspace 14B of a respective one of the four exterior side walls. Each lower level duct may connect with the respective one of the five upper level ducts communicating with the upper level hollow airspace 14 of the same wall, these two connected ducts thus forming one of the wall-connected ductwork branches 16N, 16S, 16E, 16W of Figure 3.
Five inlet control dampers 66C, 66N, 66S, 66E, 66W are installed on the five ductwork branches 16C, 16N, 16S, 16E, 16W and are operable to control the flow of air into inlet/distribution chamber 20 during operation of the heating fan in the heating mode operation.
For example, in Figure 3 each of the five inlet control dampers 66C, 66N, 66S, 66E, 66W is shown in an open position (schematically illustrated in solid lines) fully allowing flow of air into the inlet/distribution chamber 20 from the respective ductwork branch under operation heating fan in the conditioning unit 22 to induce such a flow of fresh outside air from the outside environment through the air permeable external side of the respective exterior side wall or ceiling. Each of the five inlet control dampers 660, 66N, 66S, 66E, 66W however is pivotable into a closed position (schematically shown in broken lines) sufficiently obstructing flow from the respective ductwork branch so as to substantially prevent any airflow between the hollow airspace of the respective exterior side wall or ceiling and the distribution system 18. First heating duct 68 also connects to the inlet/distribution chamber 20 of the distribution system 18, defining a sealed path from the inlet/distribution chamber 20 to the inlet side of the cold stream path of the heat exchanger 26 during heat mode operation to define an exit from the inlet/distribution chamber 20 for outside air flowing thereinto through the ductwork 16 when at least one of the inlet control dampers 66C, 66N, 66S, 66E, 66W is open.
Figure 5 schematically illustrates a control system, or CS, 70 used in the house 1 to control operation of the overall system in the heating and cooling modes of Figures 1A and 1B.
The control system 70 receives input signals from outside temperatures wall sensors N, S, E, W
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13 each mounted to the house 1 in or near the outside environment to monitor the temperature at or near the respective one of the north, south, east and west external side walls, for example to detect temperature differences at different sides of the house caused by, for example solar gains.
Other types of sensors or gauges may also or alternatively be included, for example to monitor wind pressure or speed at the different sides of the house or air flow within the ducts and the control system will use the data to from the flow and temperature sensors to optimally balance the system. The input signals received by the control system are used to control the inlet control dampers 66C, 66N, 66S, 66E, 66W during heat mode operation to control the airflow into the inlet/distribution chamber 20 of the distribution system 18 from each of the ductwork branches connected to the exterior side walls. The control system 70 also receives signals from flow sensors installed on the ductwork branches 16C, 16N, 16S, 16E, 16W and from additional temperatures sensors within the interior space 2 of the house to control operation of the overall system.
As an example, looking at Figure 1B, although only one air intake conduit 30 is shown, each exterior side wall is provided with a respective air intake conduit in the first embodiment to facilitate entry of air during cooling mode operation from selective locations. The control system 70 operates the dampers of these intake conduits, for example, to only intake outside air from the cool side of the house 1 as determined by comparison of the signals from the exterior wall temperature sensors to identify the exterior side wall having the lowest temperature.
Figure 1B shows the dampers 30A of the one illustrated air intake conduit 30 open with air entering the lower level 2B from the detected cool side of the house. The control system will balance conditions including drawing fresh air (in heating season) and exhausting air (in cooling season) with just the right amount of air passing through the exterior facing walls and ceiling to counter heat flow by conduction and also to provide fresh air required for healthy occupancy.
The 'brains' behind the system is the control system (CS) box that contains a site specific computer and software optimizing the data obtained at each building by, for example using a 'genetic algorithm' approach (McGrew in Sechbech and Gordon, 2009). This data may include measures on the unique environmental conditions facing the building (e.g.
measures of outside temperature, temperatures within each of the exterior stud wall cavities and the ceiling assembly.
Locations in the far North of Canada, or other remote areas, may necessitate a simpler and less complex control system than the one illustrated in Figures 9A, 9B, 9C and 9D.
For example, the control system may be as simple as one controlling fan speed, with a simple forward and reverse switch, triggered by outside temperature for summer and winter operation.
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14 Figure 6 illustrates an exemplary layout of ductwork within an efficient building 100 which shows a single story building.
Multi-storey buildings (e.g. two story houses) are conceptually the same with ducting at the top of each wall, led to a single distribution chamber and controlled by a system control box and sensors, and similar to the single story house with a basement. Like the house 1 of Figures 1A and 1B, the demonstration building Figure 6 has four exterior side walls, which are labeled 12N, 12S, 12E, 12W in accordance with their respective north, south, east and west outwardly facing orientations.
The ductwork features four corresponding side wall branches 16N, 16S, 16E, 16W each fluidly communicating with the hollow airspace defined within a respective one of the side walls 12N, 12S, 12E, 12W. Due to the elongated rectangular floor plan of the demonstration building, significantly longer in one direction than the other, the ceiling structure is divided into equal sized sections in the elongated direction of the building, the sections having one single hollow airspace under the interior side of the exterior facing ceiling with the air led to the air collection and distribution chamber by way of two ceiling ducts defined therein each fluidly communicating with a respective one of two ceiling branches 16C1, 16C2 of the ductwork 16.
Figure 7 shows the wall structure used in the efficient building construction of Figure 6. A stud wall assembly, having the cavities between adjacent vertical studs filled with insulation as shown schematically at 44 in the figure, has horizontal strapping, or furring, 102 fastened perpendicularly across the vertical studs at the interior side of the stud wall. Drywall, or other interior finish, 40 is fixed to the strapping 102 on the side or face thereof opposite the stud wall, the resulting open space between the stud wall and the drywall 40 defining the hollow airspace 14 within the wall structure, with the battens creating the air space staggered, so as not to impede the free flow of air in the cavity space. Vapour barrier is installed on the interior side of the airspace, as described herein above for the efficient house 1 with reference to Figure 2. On the exterior side of the stud wall is an insulating sheathing layer 46, which in the embodiment of Figures 6 to 8 is made up of a series of beadboard (expanded polystyrene, or EPS) panels 106, the sheathing layer 46 in turn having a layer of building wrap 108 (e.g. Delta Dry) installed over the outside face thereof. Finally, the outer side of the wall structure 12E is completed with breathable/air-permeable exterior siding 110.
To improve airflow between the outside environment and the hollow airspace 14 defined within the wall structure 12E, the panels 106 of the sheathing layer 46 are each provided with a series of holes 112 punched therethrough from one panel face to the opposite panel face, thereby defining channels through which air can flow across the panel 106. As shown in Figure 8, the holes 112 may be arranged in staggered parallel rows 114, 116, each row extending in an SUBSTITUTE SHEET (RULE 26) elongate vertical dimension of the panel 106 defined between opposite ends thereof. In the illustrated embodiment of the panel 106, the spacing between any two adjacent holes in the same row is the same and the inter-hole spacing of one row is equal to that of the other row. The rows 114, 116 are offset from one another in their parallel elongate directions by one-half this common straight line distance between any two holes in the same row, such that in the parallel direction defined by the rows, each hole is spaced from a corresponding hole in the other row by one-half of the distance between two adjacent holes in the same row. Cross-sectionally round and hollow cylindrical liners or inserts 118 of plastic, each having a circular cylindrical inner and outer shape, are inserted into the holes 112 in the panel 110 to help retain the shape and open condition of the holes 112 by reinforcing the panel around each hole 112 therein. Testing was performed with three beadboard panels (each sixteen inches wide and two inches thick with height of 96 inches) arranged long side edge to long side edge and equipped with fifty holes (seventeen in each of two end panels and sixteen in the middle panel between the outside panels) each of five millimeters in diameter and each fitted with a five millimeter diameter plastic drinking straw insert

15 of two and one-eight inches in length. The holes were arranged two staggered rows per panel with the holes of one row spaced vertically from those of the other by six inches and the two rows horizontally spaced by seven inches and centered over the panel's sixteen inch width. Compared to flow pressure through the same panel assembly when equipped with one hundred non-reinforced holes, the reinforced arrangement with the plastic inserts (formed by adding the inserts and taping over half of the one hundred original holes) was found to provide a greater flow pressure at a the same inside pressure and the entry of air with the 50 reinforced holes exceeded that of standard air permeable building wraps such as Tyvek, and thus was judged to be a superior arrangement in supplying fresh area to the building through the exterior walls. This reinforced arrangement would also be suitable for other insulated sheathing materials.
With further reference to Figure 7, each half of the ceiling structure 6' of the efficient building 100 is similar to the ceiling structure 6 of the efficient house of Figures 1A, 1B
and 2. Ceiling insulation 62 (e.g. fiberglass insulation) is fitted between adjacent ceiling joists with an air permeable membrane 60 (e.g. Tyvek) separated therebeneath from the vapour barrier 58 (e.g. 6 mil polyethylene sheet) that is applied next to the interior finish (e.g. drywall). The hollow airspace 14C is defined by spacing of the interior finish (e.g.
drywall) downward from the joists by strapping 64 extending perpendicular to the ceiling joists in a staggered fashion to leave spacing between strapping pieces in their lengthwise direction to allow airflow across the strapping within the airspace 14C. Like the walls, the ceiling also incorporates a layer of reflective material therein. Alternately, installation of a dimpled semi-rigid, air permeable material SUBSTITUTE SHEET (RULE 26)

16 such as Delta Dry, if perforated may provide an all-in-one solution: air space between the fiber ceiling insulation, required air permeability and required reflectivity. As shown at 126, the hollow airspaces within the wall and the ceiling 14, 14C are separated from one another along edge defined by the meeting of the interior finishes of the wall 12E and ceiling 6.
The other half of the ceiling structure 6' of the efficient building 100 is of similar construction, the hollow airspaces of the two halves being separated from one another so that each communicates with a respective one of the two ceiling braches 16C1, 16C2 of the ductwork 16.
As shown in Figures 6 and 7, the ductwork 16 may be connected with the hollow airspaces 14, 14C of the exterior side walls 12N, 12S, 12E, 12W and ceiling 6' by way of duct boots 128 connecting each duct branch 16N, 16S, 16E, 16W, 16C1, 16C2 to the hollow airspace defined within the respective wall or portion of the ceiling structure at spaced points along the duct branch. The boots of each of the side wall duct branches 16N, 16S, 16E, 16W extend horizontally from a portion of the branch extending along the respective exterior side wall parallel and proximate thereto near the upper edge thereof within the interior space of the building, while the boots of each of the ceiling duct branches 16C1, 16C2 extend vertically upward from a portion of the branch extending parallel and proximate to the ceiling within the interior space. In the efficient demonstration building of the second embodiment, the portions of the two ceiling duct branches 1601, 16C2 equipped with duct connections to the hollow airspaces of the two ceiling sections are parallel and extend across (i.e. along the short dimension) of the elongate building.
These two parallel portions of the ceiling duct branches 16C1, 16C2 are equally spaced along the building (i.e. in the direction of the building's elongate dimension) from respective end walls 12N, 12S also extending across the building 100 and are spaced apart from one another by approximately one half of the lengthwise dimension of the building's interior space. This corresponds to division of the two ceiling sections along an axis cross-wise to the building 100 half way therealong, so that each ceiling duct branch 1601, 16C2 can be considered to operate with a respective half of the overall ceiling structure.
As shown in Figure 6, the side wall branches 16N, 16S, 16E, 16W of the ductwork 16 may extend along the perimeter of the interior space of the building to connect to the inlet/distribution chamber, or !DC, 20 of the distribution system in a common space defined somewhere along a respective one of the exterior side walls, illustrated as the east wall 12E in Figure 6. Although parallel portions of the different duct branches 16N, 16S, 16E, 16W, 16C1, 16C2 are shown as being horizontally spaced from one another in Figure 6 to prevent overlap and improve clarity of the illustration, these duct portions extending toward the inlet/distribution chamber 20 may instead be vertically spaced or stacked as illustrated by the south and east wall SUBSTITUTE SHEET (RULE 26)

17 duct branches 16S, 16E in Figure 7 so as to minimize the inward distance from the walls occupied by the wall branches of the ductwork 16.
The demonstration building prototype based on the embodiment of Figures 6 to 8 was constructed, being a building twenty-two feet and eight inches wide and thirty-eight feet long using four inch diameter ducts with two inch diameter boots or other such means as establishing communication with the airspaces approximately seven feet up the walls. The linear segments of the ceiling ducts, each communicating with the respective ceiling airspace at spaced locations along the segment and extending cross-wise to the elongate floor-plan, are proposed to be positioned ten feet inward of the shorter exterior sides of the building so as to each serve a respective half of the overall ceiling structure as explained herein above with reference to Figure 6.
Figure 9 schematically illustrates operational modes of an alternate embodiment control system that switches between different operation modes based on both time and monitored conditions for an efficient dynamic-wall house or building of the type described above.
Four exterior walls NW, SW, EW, WW face north, south, east and west respectively and each have the dynamic wall structure described herein above, and a dynamic ceiling of the type disclosed above communicates with outside air via the attic space. Again, ductwork connects each dynamic wall or ceiling to a heat exchanger 26 acting as a heat recovery ventilator (HRV) or energy recovery ventilator (ERV) in an air distribution system of the building. Such as in the inlet/distribution chamber of Figure 3, the distribution system features dampers 66C, 66N 66S, 66E, 66W each operational to control airflow into the air distribution system via the ductwork feeding thereinto from the dynamic ceiling and walls. Temperature sensors are again used, but unlike the control system of Figure 5, they are located within the building and monitor airflow temperatures Tc, TNw, Ts, TEw, Tww in the ductwork between the dynamic ceiling and walls and the dampers 660, 66N 66S, 66E, 66W rather than outside air temperatures. That is, they provide ongoing monitoring of the incoming outside air after, not before, the heat transfer that occurs as the incoming air passes through the dynamic ceiling and walls.
Each air circulation branch duct from the tributary external wall, ceiling or sub-floor cavity (e.g. air drawn to recover conduction heat from an unheated crawl space) features temperature sensing of the airflow and an adjustable damper. For the purposes of the explanation, the dampers are assumed to have two selectable settings, LOW flow and HIGH flow.
The dampers are adjustable, for example, each unit being individually motorized unit, or some being slaves to a master control motor and controlled via a signal feed from the master controller, which may be located remotely from one or more of the dampers. In one embodiment, a single SUBSTITUTE SHEET (RULE 26)

18 motor may control multiple dampers that are mechanically linked. The illustrated system utilizes a single central circulation fan operable to draw air through the ducts from all the dynamic structures, which for the purpose of Figure 9 is an integral part of the heat recovery ventilator 26, although it will be appreciated that the fan may alternatively be part of a furnace or other air distribution component into which the supply air from the heat recovery unit is fed. The fan has multiple switchable or adjustable speed settings, controlled via another signal output from the master controller. For the purposes of this exemplary embodiment, the fan has three settings denoted LOW, MEDIUM and HIGH.
The switching between operational modes can be triggered by one or more of three different input options (1) Damper (Opening setting) / Flow (HRV/ERV fan-speed) parameters preset in master controller are switched based on time-of-day and calendar date reflecting seasonal variations; (2) Damper / Flow switching based on temperatures sensed in the flow in the individual ducts from each tributary area (wall or ceiling) compared to a target setpoint sensed/coded into the controller; and (3) Damper/Flow switched based on wind-speed and direction as provided to the controller from the weather station at the facility or provided from a remote source such an online public weather bureau. Wind information is fed to the control unit such and dampers are opened further or closed off more on sides exposed to wind currents and/or fan-speed is controlled in such a way as to optimize the system and keep it in balance.
Figure 9A shows a DEFAULT MODE of operation of the system. The circulation fan is operated on the LOW setting and the dampers are each partially closed into their LOW
airflow position, and the resulting airflow is the minimum required to meet the flow requirements for adequate air changes in the building as supplied by each tributary wall/ceiling/sub-floor zone.
The system may be arranged to employ this default mode of operation during a night time period, either through manual switching into and out of this mode in the evening and morning by an operator, or automatic switching into and out of this mode when a clock of the controller reaches particular hours of the day, which may be preset or user selectable, programmable, or adjustable.
Figure 9B shows a DAYTIME A.M. or MORNING mode of operation into which the system may be switched from the NIGHTTIME or DEFAULT mode of operation.
Flow is increased from selected zones based on which walls are expected to be exposed to morning sunlight (e.g. in the northern hemisphere, walls facing east, south-east and south). Thus in the drawing, dampers 66S, 66E of the south and east walls SW, EW are opened further from their partially closed positions of the default night-mode operation into their HIGH
airflow positions and the fan speed at the heat recovery ventilator 26 is increased to MEDIUM. This draws in more air from the sides of the building expected to be heated by the sun in the morning hours. The SUBSTITUTE SHEET (RULE 26)

19 setting for the ceiling damper 660 will be low or high, "LJH" depending on, for example, temperature readings from the sensors in the externally facing cavities and/or ducts, and the requirements of the interior building space.
Figure 9C shows a DAYTIME P.M. or AFTERNOON/EVENING mode of operation into which the system may be switched from the DAYTIME A.M. mode of operation.
Flow is reduced from one or more selected zones to default (LOW airflow) and increased in others to HIGH and based on the expected change of walls exposed in the afternoon and evening compared to the morning (i.e. in the northern hemisphere, the shift of sunlight exposure from the wall(s) facing east and south or southeast to the wall(s) facing west and south or southwest), and the fan speed is left at MEDIUM. Thus in the drawing, damper 66W of the west wall WW is opened further from its previous partially closed position of the night and daytime a.m. modes of operation into its HIGH airflow position, while the damper 66E of the east wall EW is return to its default partially closed LOW flow position and damper 66S of the south wall WW
is left its HIGH
airflow position. Like in the daytime a.m. or morning mode, more air is drawn in from the sides of the building expected to be heated by the sun in the morning hours, thereby increasing the heat energy being brought into the building interior space at the dynamic walls. As shown, the damper 66C for the airflow from the ceiling may also be opened to its HIGH flow position to increase airflow from the ceiling on the expectation that the roof's exposure to sunlight will cause heating of the attic space, providing more heat available to be drawn into the main interior space of the building by the incoming air.
The control system may be operable to change the hours of the day at which the operation mode switches, whether through user-programmability or automated adjustment of the mode switching times through use of a calendar used to monitor the current date for correlation with season changes, daylight savings time changes.
Figure 9D shows a DAYTIME PEAK mode of operation into which the system may automatically switch from DAYTIME A.M. or DAYTIME P.M. mode upon detecting that one or more of the airflow temperatures Tc, TNw, Tsw, TEw, Tww coming in from the respective dynamic ceiling and wall structures exceeds a setpoint temperature. The damper for each airflow detected as being warmer than the setpoint temperature (i.e. dampers 660, 66S, 66W for the illustrated example) is set to its HIGH flow position and the fan-speed is likewise increased to HIGH, thereby drawing in more air from this warmer zone.
It will be appreciated that may be possible to have more incremental fan-speeds and damper degree-of-opening positions so that the flow could be continuously variable in both volume and in draw from individual discrete source zones.
SUBSTITUTE SHEET (RULE 26) The efficient control system can functionto: (1) control and balance air flow to optimize heat transfer and meet indoor air quality standards (i.e. bring in a sufficient collective volume of air from the dynamic structures to adequately ventilate the building to such standards, while using monitored temperatures or expected sun exposure to increase the volume of air 5 where more heat energy is available to reduce heating costs), (2) daily and seasonally control air temperature according to user requirements and setpoints, (3) possibly collect air quality, temperature and energy usage data, for example at regular intervals, such as every hour, (4) possibly report data to one or more third parties every day for analysis via telecommunication, and (5) possibly monitor the system and transmit alarm notifications or signals to third parties or 10 remote locations in case of failure.
It will be appreciated that control over air pressure within the airspaces of the wall and ceiling relative to the outside air pressure of the outside environment and the inside air pressure of the interior space of the building may be controlled by systems other than a single centralized fan-based system within the conditioning unit of the distribution system. For example, 15 the airspace of each wall could have its own respective fan installed in fluid communication therewith, for example within the respective branch of ductwork to reduce the air pressure below outside and inside air pressures, thereby drawing air into the airspace from the outside environment and force it onward through the system during heating mode operation. It will also be appreciated that in such an arrangement, control over the operation of the individual fans may

20 be used to control air flow through the respective ducts in instead of using dampers. Efficient houseTM1 is a new concept that for the first time introduces air through the entire envelope, not just walls but walls and the ceiling, balancing heat losses and gains, thus improving air quality and energy efficiency throughout the entire season. This concept is more than an extension of previous work in Canada and elsewhere. It is the first system design that is optimal and, at the same time, allows for safety if the system should fail (a concern in northern communities). In other words, it provides a 'fail-safe mode should mechanical or electronic failure occur in parts or the entire system. The fail safe mode may simply be a state in which the dynamic wall system is inactive, i.e. air is not drawn dynamically through the exterior facing walls or ceiling. It is also a system that, for the first time, balances and takes advantage of typical heat losses and gains in each season, and does so in cost effective ways. In heating (winter) season, heat is recovered and used to temper incoming ventilation air by drawing in just the right amount of this air from the exterior ceiling and each exterior face ¨ north, south, east and west ¨ first through a permeable layer and then through the insulation in the exterior walls and ceiling, to a space behind their interior finish, collecting and leading this air by ductwork to a heat exchanger that transfers heat SUBSTITUTE SHEET (RULE 26)

21 from exhaust (e.g., kitchen) air to the incoming air to the furnace, all controlled by an efficient air management system. In cooling (summer) season, the system is reversed.
The invention disclosed above is a comprehensive and systematic application of the three mechanisms of heat loss and gain in houses, meeting requirements for structure durability, fresh air supply and optimal heat and cooling transfer through the exterior envelope of the building, under varying conditions such as outside wind speed, temperature and solar radiation. For example, the system invention takes into account the three main mechanisms of heat transfer through the envelope of a building: conduction, convection and radiation.
Firstly, the disclosed energy conserving approach that is more efficient than conventional buildings, since it optimally controls all three mechanisms of heating and cooling losses, gains and transfers: by including perforated rigid insulation over exterior studs to minimize thermal bridging that is common with wood frame construction; by including a radiant reflecting material within the wall and ceiling and, potentially the lower floor or basement slab to reflect heat in or away from the interior space, as external ambient and internal conditions demand; by drawing air across the envelope, differentially from all four directions, to optimally capture conductive heat loss or heat gain, and optimally reflect heat towards or away from the building, depending on demands of external ambient weather and internal load conditions.
By including a central collection, distribution and central system to optimally collect, temper, and filter and redistribute fresh to where it is needed for efficiency, health and good practice.
Secondly, the disclosed building also features a more durable structure than conventional construction since the envelope is of a rain screen type that guards against and sheds moisture and is self-drying through passage of relatively dry fresh air through the envelope, using a permeable insulation sheathing in combination with exterior fabric designed to self dry and allow fresh air across the exterior sheathing, for example using perforated rigid insulation to together with the commercially available 'Delta Dry' exterior building material that allows passage of fresh air while being self-drying with 70% reflective properties that assist in the first aspect.
Thirdly, more healthful for building occupants than conventional construction since the envelope acts as a giant air to air heat exchanger that draws in fresh air as well as partially tempering the incoming air that is further tempered, preferably by a simplified air to air heat exchanger that may be fitted with or to an electric coil to add supplementary heat when required by the building occupants, all controlled by a central control system that preferably has monitoring and communication capability.
In summary, though the idea of heat recovery and fresh air supply through exterior walls has been in the public domain for more than 30 years, the efficient house is the first SUBSTITUTE SHEET (RULE 26)

22 invention that is a total system with uniquely suitable parts. Thus this EH
invention is different in concept and detail to anything else including these earlier attempts, namely the experimental houses constructed in the late 1970s in Sweden and in the early 1980s in Ontario and Alberta, Canada where fresh air was drawn through exterior walls by depressurizing the house, and the experimental house in Scotland. Differences in key components of and benefits to the efficient house system may be summarized as follows:
1. Fresh and tempered air is drawn differentially through exterior facing walls and ceiling cavities that are created behind interior finishes. Depressurizing the space behind the ceiling and walls is different from earlier attempts to draw air through the exterior walls alone and by depressurizing the house. Drawing air from the exterior ceiling increases the area to meet fresh air requirements and provides more of the overall heat recovery system.
Robustness of the system is also improved since uncontrolled air leakage is minimized and is drawn into wall/ceiling cavities, such that these remain relatively dry without going to extraordinary measures to seal openings, as with Canada's 82000 program.
2. Pre-warmed air passing through the walls and ceiling is collected in chamber and further warmed by passing through a simplified air to air heat exchanger that needs no defrosting in the heating (winter) season since the incoming air is tempered or pre-heated, unlike that with competing devices. Not requiring defrost cycles in the heat exchanger eliminates a major reason for most existing heat exchangers failing to operate properly, or at less than full efficiency.
3. The fresh and tempered air is carried by air ducts to a fan/heat coil/furnace/conditioning/filtering system from which it is distributed. This collection and distribution is different from, for example, the Timusk house 'dumped' fresh and somewhat tempered air directly into the house. The advantages over previous inventions include differential supply and further tempering and conditioning of the fresh, tempered air, as part of the overall system of the efficient house or building, and reflection of heat back into the occupied spaces.
4. A filter in the conditioning system filters out dust and particulate matter, including any free fibers before the air is distributed throughout. This filter feature will allow improvement of indoor air quality as compared to dynamic wall or other inventions which dump air directly into the without filtering.
5. There are techniques to reduce thermal bridging in walls and improve efficiency and reduce costs in the collection and distribution of the tempered fresh air. For example, these techniques include Delta Dry building wrap combined with polyethylene cladding with SUBSTITUTE SHEET (RULE 26)

23 2. supported and perforated holes to allow air to pass through the exterior walls, and Delta Dry building wrap, perforated to allow air flow from the exterior facing ceiling.
Membranes such a Delta Dry may have reflective properties such that separate reflective materials within exterior facing walls and ceiling may not be necessary. These techniques may lead to other special assemblies such as combined rain-screen and air permeable building wraps, composite assemblies and/or preformed air plenums that might also act as architectural valences.
3. There is a control system to optimize the intake of fresh air, depending on extemal conditions and sensing devices and inline fan and/or control dampers in the ducts, so as to draw air differentially from different locations and/or directions, for example in different directions (N, S, E & W). This sensing and control subsystem helps optimize the entire system by taking account of certain conditions including wind pressure and/or solar gains.
The central control and monitoring subsystem is a key differentiating part of the efficient house and acts as the "brain" to optimize the "brawn" that is the combination of the other parts of the overall system. For example, this central control system picks up signals from the sensing devices and sends signals to other devices such as in duct fans and/or dampers to control air flow from exterior ceiling and wall areas. The central system also incorporates diagnostic logic that may signal local and/or remote panels for maintenance or repair.
7. The system can be reversed for cooling, as indicated in Sketch 1B, whereby air is drawn into the lower areas (e.g. basement) where air is cooled by running through tubes in the ground around the basement walls and then led by the conditioning/filter/control/ducting system into the wall and ceiling cavities, thereby reversing the heat flow into the house in summer (cooling) season. The advantages of the reversed mode include elimination of refrigerated air conditioning, in climates where only moderate cooling is required. This will also reduce cooling requirements in hot climates, again saving energy.
References:
Anderlind G. and Johansson B. (1983) "Dynamic Insulation: A Theoritical Analysis of Thermal Insulation through which a Gas or a Fluid Flows," The Swedish Council for Building Research, Stockholm 68 p.
Brown A., lmbabi M., Murphy J., Peacock A. (2008) "The transforming Technology of the Dynamic Breathing Building", Proceedings, Ecocity World Summit, San Francisco, August, 11 p.

24 DeProphetis B. (2006) "Roadblocks of Innovation: Commercial Failure of a Promising Canadian Home Building Technique", M. Mgmt., Lakehead University, Canada, 174 p.
Forest S. (2004) "How sick is your home? Business Week 9th August, pp. 66-68.
Goddard L., Guillas and Pang L. (1999) "The Future of Housing Markets in Canada: with a focus on Thunder Bay," undergraduate report, Lakehead University, 38 p.
Levon B. (1986) "Experimental Buildings in Scandinavia", The Swedish Council for Building Research, Stockholm, pp. 158-160.
MacKay V. (1990) "Dynamic Wall Demonstration Project", Innovative Housing Grants Program, Alberta Municipal Affairs, Edmonton Alberta, 90 p.
McGrew, S. P (2009) ?
Poulin, M. and A.B. Polkki (2008), "The Effect of an Altemate Insulation Method on Heat Contained in a Building", unpublished report, Winston Churhchill High School, December.
Swinton, Brown and Chown (1995) "Controlling the Transfer of Heat, Air and Moisture through the Building Envelope', in Building Science Insight, IRC-NRC-CNRC.
Timusk J. (1987) "Design Construction and Performance of a Dynamic Wall House", 8th Air Infiltraion Centre Conference, Sept. 24, Uberlingen, FRG, 17 p.
Thoren T. (1982) Dynamic Insulation Controls Flow of Heat Energy,"
Canadian Building, November/December, pp. 45-47.
Walker D. and Poulin B. (2005) "Efficient Housing Business Plan", unpublished report, Lakehead University, 22 p.

Claims (20)

1. An efficient building using airflow across one or more exterior walls to counteract heat transfer thereacross, said one or more exterior walls each having a dynamic wall structure comprising:
a stud wall layer comprising a series of wall studs spaced along a length of the wall structure with stud cavities between adjacent studs and air-permeable wall insulation material disposed within the stud cavities;
an air-permeable external insulation layer comprising rigid insulation panels fixed to the wall stud layer on an exterior side thereof facing outwardly away from an interior space of the building toward an external environment outside the building;
a building wrap layer disposed on an exterior side of the rigid air-permeable insulation panels facing away from the wall studs; and heat reflecting material arranged within the wall structure to reflect radiant heat back away from the wall in both directions.

2. The efficient building of claim 1 wherein the building wrap layer is perforated.

3. The efficient building of claim 1 or 2 wherein the rigid insulation panels are perforated.

4. The dynamic wall structure of any one of claims 1 to 3 comprising an interior finishing layer disposed on a side of the stud wall layer opposite the external insulation layer.

5. The efficient building of claim 4 comprising a hollow wall cavity disposed between the stud wall layer and the interior finishing layer, the hollow wall cavity being coupled to a depressurization source for depressurization of the wall cavity to draw external air thereinto through the air permeable building wrap, external insulation and stud wall layers.

6. The efficient building of claim 4 or 5 comprising a vapour barrier layer disposed between the stud wall layer and the interior finish layer.

7. The efficient building of any one of claims 1 to 6 comprising a dynamic ceiling structure supported over the interior space of the building atop the exterior walls thereof, the dynamic ceiling structure being in fluid communication with the external environment and comprising:
a ceiling joist layer comprising a series of ceiling joists spaced along a dimension of the ceiling structure with joist cavities between adjacent joists and air-permeable ceiling insulation material disposed within the joist cavities; and additional heat reflecting material arranged within the ceiling structure to reflect radiant heat back away from the ceiling in both directions.

8. The efficient building of claim 7 wherein the dynamic ceiling structure comprises an air permeable membrane layer.

9. The efficient building of claim 7 or 8 comprising a ventilated attic space disposed between a dynamic ceiling structure of the building an a roof thereof, whereby the dynamic ceiling structure is fluidly communicated with the external environment by ventilation of the attic space.

10. The efficient building of any one of claims 1 to 9 wherein multiple ones of the exterior walls each have the dynamic wall structure, and the building comprises a control system arranged to control airflow into the building through the dynamic wall structures from to the external environment outside the building based on monitoring of conditions by a monitoring system.

11. The efficient building of claim 10 comprising ductwork communicating with the dynamic wall structures and connecting said dynamic wall structures to an air distribution system including at least one discharge opening that feeds into at least one area of the interior space of the building, the control system being arranged to control dampers installed in said ductwork between the dynamic wall structures and the air distribution system.

12. The building according to claim 11 wherein the air distribution system comprises a heating device operable to heat air received from the dynamic wall structures through the ductwork before discharge into the interior space of the building.

13. The building according to claim 11 or 12 wherein the air distribution system comprises a central fan operable to draw air through each dynamic wall structure when said dampers are open.

14. The building according to any one of claims 10 to 13 wherein the monitoring system comprises an inside temperature sensor arranged to measure an inside temperature within the building.

15. The building according to any one of claims 10 to 14 wherein the monitoring system comprises outside temperature sensors each arranged to measure a respective outside temperature proximate an exterior side of a respective one of the plurality of exterior walls.

16. The building according to any one of claims 10 to 15 wherein the control and monitoring systems are arranged to change airflow through the dynamic wall structures based on a monitored time of day.

17. The building according to any one of claims 10 to 16 wherein the control and monitoring systems are arranged to provide greater airflow through a sunlight-exposed dynamic wall structure than an opposing dynamic wall structure.

18. The building according to claim 17 wherein the control and monitoring systems are arranged to change which of the dynamic wall structures is subject to the greater airflow therethrough during the day in order to follow which of said dynamic wall structures is exposed to sunlight through the day.

19. The building according to claim 17 or 18 wherein the control and monitoring system are arranged to set equal airflow control conditions among the dynamic wall structures for nighttime operation.

20. The building according to any one of claims 10 to 19 wherein the control and monitoring systems are arranged to monitor temperatures of airflows passing through respective ones of the dynamic wall structures and increase an airflow rate of a respective dynamic wall structure for which the monitored temperature exceeds a setpoint temperature.
22. The building according to any one of claims 1 to 9 comprising a control system that is operable in a cooling mode to deliver inside air from a lower level of the building's interior space to the dynamic wall structures through an air distribution system coupled thereto to force the lower level internal air out of the building through the dynamic wall structures, the air forced out through the dynamic wall structures carrying heat to the external environment that would otherwise be transferred into the building.
23. The efficient building according to any one of claims 1 to 22 wherein each rigid insulation panel has inner and outer faces facing the interior space of the building and the external environment respectively, the panel having a plurality of holes formed therein to extend fully therethrough from the inner face to the outer face and a plurality of hollow inserts received in respective ones of the plurality of holes, each hollow insert being hollow between opposite open ends thereof and having an outer size and shape arranged to fit against the rigid insulation panel at the perimeter of the respective hole to reinforce an open condition thereof between the inner and outer faces of the rigid insulation panel.