EP2542729A1

EP2542729A1 - Dynamic insulation

Info

Publication number: EP2542729A1
Application number: EP20110710007
Authority: EP
Inventors: Alexander Brown; Andrew Peacock
Original assignee: Energyflo Construction Technologies Ltd
Current assignee: Energyflo Construction Technologies Ltd
Priority date: 2010-03-01
Filing date: 2011-03-01
Publication date: 2013-01-09
Also published as: WO2011107731A1; US20130008109A1

Abstract

Dynamic Insulation for a building or structure comprising an external surface and an internal surface; at least one heat transfer layer between the internal and external surface; a supply for supplying air to the heat transfer layer, and a collector for collecting air that has flowed through the heat transfer layer. Pressure is regulated through the dynamic insulation. Air is supplied to the dynamic insulation from the interior or the exterior of the building or structure and/or exhausted to the Interior or exterior of the building or structure.

Description

Dynamic Insulation

Field of the Invention

The present invention concerns a dynamic insulation arrangement for a building, a panel and a building envelope or facade.

Background of the Invention

In recent years, there has been increasing interest in the use of dynamic insulation in buildings as a way to improve energy efficiency. Dynamic insulation beneficially combines insulation and ventilation functions to reduce fabric energy loss through the building envelope. Dynamic insulation works by redirecting fabric heat or coolth loss though a building's fabric to recover energy. In winter, relatively cold outside air is pre-heated as it passes through the dynamically insulated fabric into the heated building. Conversely, in summer, the relatively warm outside air is pre-cooled as it passes through the fabric into the cooled building. The result is the creation of a thermal barrier between indoor spaces and outdoor ambient.

Conventional dynamic insulation returns thermal energy normally transmitted and lost through the building envelope to the interior of the building in the form of pre- tempered air. As such, energy loss through the envelope fabric to outside ambient is significantly reduced. However, internally driven over-heating has become an increasingly common problem with improved insulation and air tightness levels, especially in high density occupancy buildings like offices and schools. This presents a potential limitation to the more widespread adoption of low U-value insulation systems including dynamic insulation.

Summary of the Invention

According to a first aspect of the present invention, there is provided dynamic insulation for a building or structure, the dynamic insulation comprising an external surface and an internal surface; at least one heat transfer layer between the internal and external surface; a supply for supplying air to the heat transfer layer; a collector for collecting air that has flowed through the heat transfer layer and means for regulating pressure through the dynamic insulation. Air may be supplied to the dynamic insulation from the interior and/or the exterior of the building or structure and/or exhausted to interior or exterior of the building or structure. According to second aspect of the present invention, there is provided dynamic insulation comprising an external surface and an internal surface; at least one heat transfer layer between the external and internal surface, a supply for supplying air to the heat transfer layer; a collector for collecting air that has flowed through the heat transfer layer and an exhaust to allow air that has passed through the heat transfer layer to be exhausted outside the building or structure.

The heat transfer layer may comprise an air channel or an air permeable layer through which air can flow. Where the heat transfer layer is an air permeable layer, the supply and / or collector may comprise a plenum.

The air permeable layer is a material layer that air can pass through without being an open channel. An alternative description of the air permeable layer is: air permeable material; air permeable structure; air permeable membrane; air permeable element; breathable structure; breathable material; breathable layer; breathable element; breathable membrane.

Air may be supplied to the dynamic insulation from an interior of the building or structure and /or from the exterior. Means may be provided for switching between at least two of: a first mode in which air is supplied to the dynamic insulation from the exterior and is directed to the interior; a second mode in which air is supplied to the dynamic insulation from the exterior and exhausted to the exterior and a third mode in which air is supplied to the dynamic insulation from the inside and exhausted to the outside. Any suitable mode switching mechanism may be used. For example, the mode switching mechanism may include one or more selectively openable or closable valves for selectively defining the air flow path. Means may be provided for controlling the magnitude and/or direction of airflow, optionally wherein the means for controlling comprises at least one fan and/or a damper and/or a valve and/or a grille. Means for regulating the pressure may be provided to define a pressure ratio, where the pressure drop derived from the average airflow in the heat transfer layer is at least 50% of that in the supply and/or collector; for example more than 60%; more than 70%; more than 80%; more than 90%, more than 100%, more than 120%, more than 140%, more than 160%.

The means for regulating pressure may comprise at least one dimension of the channel where the heat transfer layer is an air channel or at least one dimension of a plenum where the heat transfer layer is a air permeable layer. The means for regulating pressure may comprise at least one constriction, optionally wherein the constriction is located in one or more of the supply, collector or heat transfer layer.

Where the heat transfer layer is an air channel, the supply and / or collector hydraulic radius may be greater than the air channel hydraulic radius.

Where the heat transfer layer is an air channel, the supply and/or collector area, Aeon, is preferably greater than the total air channel area per metre along the collection length, ,, selected from: A_co,_l>30% Acwm, Acon 40% Acwm, Acoii>50% Ach/_m, Acoii>60% Ach/m, Acoii>70% Α^π,.

Where the heat transfer layer is an air channel, the supply and/or collector depth, dcoii, is preferably greater than the total air channel depth, dch, for example selected from: d_coli>80%d_ch, d_COii>100%d_ch, d_∞n>120% d_ch, d_∞n>150% d_ch.

Where the heat transfer layer is an air channel, the at least one dimension may comprise the air channel depth, d_ch, and air channel length, , and the ratio of d_C to lc_his selected from: dch<2.5%l_Ch; d_ctl<2.0%l_ch; d_Ch<1.5%l_cn; d_ch<1.0%l_ch. Multiple heat transfer layers may be provided, optionally separated by support posts. In this case, the post width, w_p, and heat transfer layer width, Wch, are selected from: The supply and/or the collection pull length, l_∞n, from the first point supplying to or collecting from to the entrance or egress to the dynamic insulation supply or collection area may be selected from:

The supply and/or the collection pull length, leeway, from the first point supplying to or collecting from to the last point by a single entrance or egress to the dynamic insulation suppl

The inner and/or outer layer may have an R-value greater than 0.2m²KW¹; optionally greater than 0.3m²KW^"1; optionally greater than 0.4m²KW¹; optionally greater than 0.5m²KW^"1; optionally greater than 0.6m²KW¹; optionally greater than 0.7m²KW¹; optionally greater than 0.8m²KW^"1; optionally greater than 0.9m²KW^"1; optionally greater than 1.0m KW¹.

Where the heat transfer layer is a air permeable layer, the R-value of the air permeable layer is preferably greater than 0.2m²KW^"1; optionally greater than 0.3m²KW^"1; optionally greater than 0.4m²KW¹; optionally greater than 0.5m²KW¹; optionally greater than 0.6m²KW^'1; optionally greater than 0.7m²KW¹; optionally greater than 0.8m²KW^"1; optionally greater than 0.9m²KW^'1; optionally greater than 1.0m²KW¹; optionally greater than 1.25m²KW^"1; optionally greater than 1.5m²KW^'1; optionally greater than 1.75m²KW^"1; optionally greater than 2.0m²KW^"1. The external surface and the internal surface may form part of an integrated panel for fitting to a building or structure.

The integrated panel may have a U-value lower than 2Wm^"zK^'1; preferably lower than 1.5Wm^"2K^"1; optionally lower than 1Wm^" K^"1; optionally lower than 0.75Wm^'2K^'1; optionally lower than 0.5Wm^'2K^"1; optionally lower than 0.4Wm ²K^"1; optionally lower than 0.3Wm^"2K^"1; optionally lower than 0.2Wm^'2K^'1.

According to another aspect of the invention, there is provided a building envelope construction comprising dynamic insulation of the first and/or second aspects of the invention, wherein the building envelope has a U-value lower than 2Wm^{"2 "1}; preferably lower than 1.5Wm^" K^"1; optionally lower than 1Wm^"2K^"1; optionally lower than 0.75Wm^"2K^'1; optionally lower than 0.5Wm^"2K^"1; optionally lower than 0.4Wm^"2K^" ¹; optionally lower than 0.3Wm^"2K^"1; optionally lower than 0.2Wm^" K^"1.

Dynamic insulation wherein one of the internal or external surfaces is part of the building or structure.

According to another aspect of the invention, there is provided a building or structure that is fitted with the dynamic insulation of the first and/or second aspects of the invention.

According to another aspect of the invention, there is provided a method for assembling dynamic insulation of the first and second aspects of the invention comprising attaching the insulation to a building or structure.

The building or structure may form part of the insulation. Alternatively, the dynamic insulation may be provided as an integral unit or panel for fitting to a building or structure. In either case, the insulation may be secured to the building using any suitable techniques.

The insulation may be attached to an existing building or structure or may be included in a new building as part of the building process, for example, in new-build houses or any other new building.

Brief Description of the Drawings

Illustrative embodiments of the present invention will now be described with reference to the drawings in which: Figure 1 (a) shows a cross-section through dynamic insulation, in which an air channel is used for heat collection, and the direction of airflow is from outside the building to inside;

Figure 1 (b) shows a cross-section through dynamic insulation, in which a air permeable element is used for heat collection, and the direction of airflow is from outside the building to inside;

Figure 2 illustrates pressure drop points for the dynamic insulation of Figures 1(a) and 1(b);

Figure 3 shows an exploded view of a collector region of the dynamic insulation of Figure 1 (a);

Figure 4(a) is similar to Figure 3, but shows dynamic insulation in which the heat transfer layer is an air channel and posts divide the internal space;

Figure 4(b) shows dynamic insulation in which the heat transfer layer is a air permeable layer and posts are provided in various positions;

Figure 5(a) shows an entrance / egress point for the dynamic insulation of

Figures 1 (a) and 4(a);

Figure 5(b) shows an entrance / egress point for the dynamic insulation of Figures 1 (a) and 4(a);

Figure 6(a) shows a cross-section similar to Figure 1(a), but in which the direction of airflow is from outside the building to outside the building;

Figure 6(b) shows a cross-section similar to Figure 1(b), but in which the direction of airflow is from outside the building to outside the building;

Figure 7 is a plot of heat transfer coefficient (U) versus airflow velocity for the dynamic insulation of Figures 1 and 6;

Figure 8(a) shows a cross-section similar to Figure 1 (a), but in which the direction of airflow is from inside the building to outside the building;

Figure 8(b) shows a cross-section similar to Figure 1 (b), but in which the direction of airflow is from inside the building to outside the building;

Figure 9 is a plot of heat transfer coefficient (U) versus airflow velocity for the dynamic insulation of Figure 8;

Figure 10 shows airflow when dynamic insulation is switched off or prevented from operating, and

Figure 1 is a schematic view of ducting in a roof space into which the dynamic insulation of Figures 1 , 6 and 8 may move through between the dynamic insulation and the supplied or extracted environment. Detailed Description of the Drawings

Figure 1 (a) shows dynamic insulation 10 that has an external panel or wall 12 and an internal panel or wall 14, which combine to define an airflow channel 16 between them. The airflow channel 16 extends over substantially all of the surface area of the panels 12 and 14 and is closed at its ends. Formed through a lower end of the external panel 12 is a conduit 18 that allows air to flow from outside into the airflow channel 16. Formed through an upper end of the internal panel 14 is a conduit 20 that allows air to flow from the airflow channel 16 into the building. The conduits 18, 20 are positioned to maximise their air flow separation.

In use, airflows from the outside through the conduit 18 in the lower end of the external panel 12, up through the airflow channel 16 and exits through the conduit 20 at the upper end of the internal panel 14. In this case, the airflow channel 16 can be considered a heat collection stage and the conduits 18 and 20 act as the air supply/collection stages.

Figure 1 (b) shows dynamic insulation 10 that has an external panel or wall 12, an external panel or wall 14 and an airflow channel between them. The airflow channel extends over substantially all of the surface area of the panels and is closed at its ends. Located in the airflow channel is an air permeable element 22 capable of transmitting thermal energy and acting as a dynamic insulator. The air permeable element 22 extends along the full-length of the airflow channel, so that to flow from one side to the other air has to pass through the air permeable element 22. Between the air permeable element 22 and the external panel 12 an outer plenum 24 is formed. This extends over substantially all of the area of the permeable layer 22. Between the air permeable element 22 and the internal panel 14 an inner plenum 26 is formed. This extends over substantially all of the area of the permeable layer 22. Formed through a lower end of the external panel 12 is a conduit that allows air to flow from the outside into the outer plenum 24. Formed through a lower end of the internal panel 14 is a conduit that allows air to flow from the inner plenum 26 into the building. The conduits formed through the external and internal panels 12 and 14 are positioned substantially opposite each other. In use, air flows from the outside through the entrance conduit in the lower end of the external panel 12, and into the outer plenum 24 between the external panel and the air permeable element 22. It then flows through the air permeable element 22 and into the inner plenum 26, where it flows towards and through the egress conduit at the lower end of the internal panel. In this case, the air permeable element 22 can be considered the heat collection stage and the outer and inner plenums 24 and 26 act as the air supply/collection stages.

For dynamic insulation to operate efficiently, the ventilation and conductive heat paths have to cross to allow heat exchange. To optimise this exchange, a near even airflow through the heat transfer layer is needed. This can be achieved by maintaining a balance in the pressure drop involved in the heat transfer layer and the pressure drop in the air supply/collection stage. To ensure that air flows as required, the pressure drop in supply/collecting air must not significantly dominate the pressure drop in the heat transfer layer. The pressure drop is measured in the direction of air flow. Figure 2(a) shows the area over which the pressure is measured for the supply/collection and heat collection stages of the insulation of Figure 1(a). Figure 2(b) shows the area over which the pressure is measured for the supply/collection and heat collection stages of the insulation of Figure 1(b).

While some unevenness in airflow can be accommodated through some areas supplying more heat and others less, air has to be controlled to ensure the heat is collected. If the airflow is too uneven there will be areas where there is very low airflow and as a consequence no dynamic insulation effect. To control air movement, pressure drop through the dynamic insulation has to be controlled. To ensure that the complete system is economical the control should happen in the dynamic insulation.

Ideally, the ratio of the pressure drop in the heat collection stage (dPd to pressure drop in the supply/collector stage (dP_∞n) (based on the simplified assumption of an even flow distribution at the heat collection stage) should be more than 0.5:1.0 (pressure drops shown in Figure 5(a)). This can vary and could be more than 0.6:1.0, more than 0.7:1.0, more than 0.8:1.0, more than 1.0:1.0, more than 1.0:0.9, more than 1.0:0.8, more than 1.0:0.7, more than 1.0:0.6. In reality, the airflow will not be even in the heat collection stage. However, unevenness in air collection/distribution is limited in that the pressure drop in collection increases rapidly as it moves to the take-off point. So there is a small proportion of the air channel with an increase in airflow while the majority suffers only a slight drop. Therefore, where pressure is successfully balanced, there is little effect on the overall heat loss as the positive and negative effects will be in balance.

A number of factors influence the pressure drop. These include the channel depth, the presence or otherwise of posts, the length and depth of the channel, the size of the air permeable element (if there is one), grilles, dampers, other constrictions and meandering flow paths. To ensure that as little insulation as possible is removed, it is beneficial to keep channels as small as possible. To ensure, the pressure drop is not too large they should be as deep as possible. To ensure that the collection pressure is not too limited channel/air permeable layer pressure should be above a certain level to allow a suitable length of collection. The schematic views of Figures 2(a) and (b) show some of the channel dimensions. In Figure 2(a), d_Ch is the depth of the channel and is the length of the channel. To ensure the required pressure drop can be achieved, ideally: d_ch<2.5% l_Ch; d_ch<2.0% 'en; d_cfl<1.5% lch! d_ch<1.0% lch. In Figure 2(b), d_p is the depth of the plenum and l_p is the length of the plenum. To ensure the required pressure drop can be achieved, ideally: d_p<2.5% l_p; d_p<2.0% l_p; d_p<1.5% l_p; d_p<1.0% l_p.

Figure 3 shows a more detailed view of the airflow collector and airflow channel of the arrangement of Figure 1 (a). As shown in Figure 3, typically, the collector is a channel or conduit that extends over the whole of the end of the air channel and has an egress along its length through which air exits. The relative sizes of the collection depth, dcoii, and the channel depth, d_Ch, have to be selected to control the pressure drop. Ideally, Where an air permeable layer is used, the relative sizes of the collection depth, dcon, and the plenum depth, d_p, have to be selected to control the pressure drop. Ideally,

The relative sizes of the collection area and the air flow channel / plenum area also need to be considered. Ideally, the collection area, Aeon, is greater than 0.3*the air flow channel / plenum area per metre run length along the collector (Ι∞ιι), ^ nim, A_p/m, i.e. A_CO|,>0.3*Ach/m or Αα,ιι>0.3*Α_ρ/Γη In many cases, Aoou 0.6*Achftn; AcQi,>0.7*Ach/m or A_COii>0.4*A_p/_m; Acoii>0.5*A_p/m; A_col|>0.6*A_p/m; A_COii>0.7*Ap _m.

In some dynamic insulation, structural posts are provided along the panels. Figure 4(a) shows an example of a panel in which posts are provided. Where posts are included they should have a width that is less than 2x the width of channels, for example less than 1.5x, 1.0x, 0.75, 0.5x. This is allows thermal transfer past the channels. While Figure 4(a) shows posts for the embodiments of dynamic insulation where the heat transfer layer is an air channel, the terms and definitions can equally apply to dynamic insulation where the heat transfer layer is an air permeable layer. In this situation, the post could be in the air permeable layer; in an air permeable layer and a single plenum; or an air permeable layer and two plenums as shown in Figure 4(b).

Air must be supplied to and collected from the heat transfer layer(s). This is done using supply / collector via entrance / egress points in the supply / collector. To do this economically the frequency of entrance and/or egress may be limited, at least in one of the supply or collection.

Consider firstly the maximum distance air will travel to get to/from the egress/entrance point. This is given the term Ι_∞ιι· This is shown in Figure 5(a) for dynamic insulation in which the heat transfer layer is an air channel and Figure 5(b) for dynamic insulation in which the heat transfer layer is an air permeable layer. Ideally,

Alternatively, consider the maximum coverage from a single entrance/egress point measured as a span. This can be given the term leeway, as it refers to the centre to centre distance of entrance/egress points or centre to centre distance of the extreme points that air is moved from/to from by a single entrance/egress point. This is also shown in Figures 5(a) and (b). Ideally,

The relative shapes of the air channel or plenum and collector also play a part. Ideally, the hydraulic radius of the collector is greater than that of the channel / plenum. Hydraulic radius is area over perimeter. This ensures the channels and collectors to be any shape or construction as long as they are suitably sized. For example, the collector could merely be a gap or channel between the end of the air flow channel and the building or could be a separate element built as part of the panel.

Another consideration in the efficiency of dynamic insulation is the R-value of the individual components as well as the overall R-value. The R-value is the conventional measure of thermal resistivity, i.e. the temperature difference and area relative to the heat loss over the area. It is commonly used to describe building components such as insulations brick and blockwork. R-values are the reciprocal of U-values. U-value is the overall heat transfer coefficient and is the heat loss over area and temperature difference of a full construction element such as a floor, roof or wall. In order to optimise performance, it is preferred that the inner and/or outer layers have an R-value greater than 0.2m²KW^'1; optionally greater than 0.3m²KW^"1; optionally greater than 0.4m²KW¹; optionally greater than 0.5m²KW^"1; optionally greater than 0.6m²KW^"1; optionally greater than 0.7m²KW¹; optionally greater than 0.8m KW^"1; optionally greater than 0.9m²KW¹; optionally greater than 1.0m²KW^"1.

In the embodiment of Figure 1 (b), the R-value of the air permeable element is also important. For this, it is preferred that the R-value is greater than 0.2m KW¹; optionally greater than 0.3m KW^"1; optionally greater than 0.4m²KW^'1; optionally greater than 0.5m W^"1; optionally greater than 0.6m² W^"1; optionally greater than 0.7m²KW¹; optionally greater than 0.8m²KW^"\ optionally greater than 0.9m²KW^~1; optionally greater than 1.0m²KW¹; optionally greater than 1.25m²KW^"1; optionally greater than 1.5m²KW^'1; optionally greater than 1.75m²KW^"1; optionally greater than 2.0m²KW¹. Overall, the integrated panel or building element preferably has a conventional U- value lower than 2Wm^"2K^"1; preferably lower than 1.5Wm^"2K^"1; optionally lower than 1Wnr²K^'1; optionally lower than 0.75Wm^" K^"1; optionally lower than 0.5Wm^"2K^"1; optionally lower than 0.4Wm^'2K^'1; optionally lower than 0.3Wm^"2K^"1; optionally lower than 0.2Wm^'2K^'1. The above features may be used separately or in combination in any of the dynamic insulation described herein.

Figure 6(a) shows dynamic insulation that has an external panel or wall 12 and an internal panel or wall 14, which combine to define an airflow channel 16 between them. The airflow channel 16 extends over substantially all of the surface area of the external and internal panels and opens at its upper end after air is collected, to allow air to be exhausted from the building. Formed through a lower end of the externa) panel is an entrance that allows air to flow from outside into the supply for the airflow channel. The supply and collection areas in the internal and external panels are positioned to maximise their air flow separation. In this case, the airflow channel 6 is the heat collection stage and the lower entrance in the external panel is the air supply stage. In use, air flows from the outside through the entrance in the lower end of the external panel, up, through the airflow channel prior to collection and exhaust. Although not shown in Figure 6(a), an air collection stage (typically in the form of a conduit or pipe) is provided at the end of the airflow channel to collect air prior to exhaust from the building. An egress or exit opening is provided along the collector to allow air to exit (for example as shown in Figure 5(a)). Figure 6(b) shows dynamic insulation that operates on a similar principle to Figure 6(a), but includes an air permeable element capable of transmitting thermal energy and acting as a dynamic insulator. As before, the insulation has an internal panel or wall, an external panel or wall and an airflow channel between them. The airflow channel extends over substantially all of the surface area of the panels. Located in the airflow channel is the air permeable element. The air permeable element extends along the full-length of the airflow channel, so that to flow from one side to the other air has to pass through the air permeable element.

Between the outer panel 13 and the air permeable element 22 an outer plenum 24 is defined. Likewise between the inner panel 14 and the air permeable element 22 an inner plenum 26 defined. Formed through a lower end of the external panel 12 is an entrance that allows air to flow from the outside into the airflow channel. In the inner plenum 26 there is an egress point at its upper end to allow air to flow to the outside of the building. In use, air flows from the outside through the entrance conduit in the lower end of the external panel, and into the outer plenum 24. It then permeates through the air permeable element 22 and into the inner plenum 26. During this process, the intermediate layer material 22 functions as a heat exchanger, transferring heat to the air as it passes slowly through it. This results in the air in the inner plenum 26 being pre-tempered to a different temperature to the outside air in the outer plenum 24. Once in the inner plenum 26, air flows towards and through the egress opening at the inner plenum end to the exterior of the building. The fresh air bypass supplies fresh outside air directly to the interior of the building, and the exhaust conversely exhausts stale air from the interior out of the building.

In the situation of overheating of a building, there is an excess of heat in the interior of the building. In this situation, the arrangements of Figures 6(a) or 6(b) prevent warm air being directed into the building. Outward conduction of internal heat through the building envelope results in the internal wall and/or air permeable element 22 being warmed. Therefore, incoming air from outside the building passing through the air channel 16 (Figure 6(a)) or air permeable element 22 (Figure 6(b)) is heated, so the air reaching the collector is warmer than the outside air. This warm air is exhausted to the exterior of the building. Because of this, heat from the air channel 16 or air permeable element 22 is transferred away, rather than being recovered to the interior of the building. Therefore, there is an increase in the rate of cooling because heat is lost through dynamic heat exchange, in addition to conductive heat loss through the building envelope. The benefit of exhausting air that has passed through the insulation to the exterior of the building, as opposed to the interior as is conventional, is illustrated in Figure 7. This shows plot of the heat transfer co-efficient versus air flow velocity for the situation where air is exhausted into the interior of the building (right hand plot) and a similar plot where air is exhausted to the exterior of the building (left hand plot). It is clear from this the heat transfer effect is greater when air is exhausted to the exterior of the building.

Figure 8(a) shows another dynamic insulation arrangement. Again, this has an external panel or wall 12 and an internal panel or wall 12 defining an airflow channel 16 between them. The airflow channel extends over substantially all of the surface area of the panels 12 and 14 and is closed at its lower end and open at its upper end to allow air to be exhausted from the building. Formed through an upper end of the internal panel 12 is a conduit 28 that allows air to flow from the building through the dynamic insulation entrance into the airflow channel via the supply conduit. Formed through a lower end of the external panel 12 is a conduit that allows air to flow from airflow channel to the outside of the building through an air egress. The conduits in the internal and external panels 12 and 1 are positioned to maximise their air flow separation, so that air flows across as much of the panels as possible. In this case, the airflow channel 16 is the heat dissipation stage and the upper conduit in the internal panel 12 acts as the air supply stage. In dynamic exhaust, stale air is moved into the dynamic element from the building may be provided with an exhaust air bypass to allow stale air to flow from the interior when the exhaust dynamic insulation is not in operation. In use in a heating situation, exhaust air comes from the warm indoor space and leaves the building at substantially the same temperature as the indoor space. Energy in the exhausted ventilation air is sacrificed for the greater good of maintaining a shallow temperature gradient of an inner layer, thereby reducing heat/coolth loss to the dynamic element. As the internal air needs to be replaced exhaust air is a waste product that has to be removed from the building. Using the energy in the air that would be lost to reduce heat transfer into a building element is the principle of exhaust dynamic insulation.

Figure 8(b) shows dynamic insulation that operates in a manner similar to that of Figure 8(a). This has an internal panel or wall, an external panel or wall and an airflow channel between them. The airflow channel extends over substantially all of the surface area of the panels and is closed at its ends. Located in the airflow channel is an air permeable element capable of transmitting thermal energy and acting as a dynamic insulator. The air permeable element extends along the full- length of the airflow channel, so that to flow from one side to the other it has to pass through the air permeable element.

Between the air permeable element and the external panel an outer plenum is formed. Between the air permeable element and the internal panel an inner plenum is formed. Formed through a lower end of the internal panel is a conduit that allows air to flow from the inside of the building into the inner plenum. Formed through a lower end of the external panel is a conduit that allows air to flow from the outer plenum to the outside of the building. The conduits formed through the external and internal plenums are positioned substantially opposite each other.

In both of the cases shown in Figures 8(a) and 8(b), air is moved through the dynamic insulation from the inside to the outside. Doing this may be more desirable than conventional dynamic insulation depending on the outdoor conditions, such as temperature and humidity. To aid the flow of air from the inside to the outside, a fan (not shown) may be provided. This would be arranged to drive air from the interior of the building into the dynamic insulation and through the airflow channel or the air permeable layer. The fan may be located within the conduit in the internal panel or, for example, in an air supply to the interior pressurising the internal space. Figure 9 shows the heat dissipation trend based on inlet air flow velocity for the panel with the inlet flow is measured at the inlet in the internal panel. As can be seen, when air is driven out of the building through the dynamic insulation, low levels of heat dissipation are achieved. The different modes of operation described above may be used independently or in combination. For example, a controller may be provided for switching between at least two of: a first mode in which air is supplied to the dynamic insulation from the exterior and is directed to the interior; a second mode in which air is supplied to the dynamic insulation from the exterior and exhausted to the exterior and a third mode in which air is supplied to the dynamic insulation from the inside and exhausted to the outside. Any suitable mode switching mechanism may be used. For example, one or more selectively openable or closable valves may be provided for selectively defining the air flow path. Equally, two or more of the modes of operation may be used in tandem, for example, with the walls operating in one mode, roof in the other. Alternatively, the modes of operation may be used in sequence, for example, the roof may be operated in one mode during a first time period and then switched to operate to another mode during a second time period.

Furthermore, parts of a large structure could operate in different modes concurrently. For example the rear walls of a large building may operate in normal heat recovery mode, while the front walls operate in the cooling mode. The roof may then operate in a combination of normal mode in some areas and the cooling mode. Equally, the dynamic insulation could be switched off so that the building is merely ventilated using conventional ventilation, as shown in Figure 10. The versatility and ability of the insulation to switch between different modes underpins the concept of adaptive building envelopes that result from the application of dynamic insulation.

One or more constrictions may be provided within the dynamic insulation. These are elements that reduce the area available for air to flow through and so produce a disproportionate pressure drop relative to their dimensions in the overall channel, plenum, supply or collection. These can be embodied as denser layers or sheets in an air permeable material. In the case of open channels, plenums, open supply or collectors, a constriction could be a grille or a section where the air moves over a smaller cross-sectional area. Also the depth, width or other dimension of the supply and/or collector and/or heat transfer layer may be reduced over a section. A constriction could also be a component that alters the air movement of air to produce a less direct path.

The present invention provides a versatile, adaptive approach to ventilation that extends the functionality of dynamic insulation to include both heat recovery and heat dissipation. This allows for year-round comfort and low energy consumption, without the need for expensive air conditioning. It may be applied to all dynamically insulated parts of the building envelope, including walls, roofs, ceilings and floors. In addition, the present invention may be applied to all building types, as well as to other structures and platforms.

Positioning of the supply and collection points is not limited to those positions mentioned in the text and shown in the Figures. Air can enter and exit dynamic insulation at any point where there is sufficient pressure control to allow air to spread over the dynamic element. In the single channel embodiment shown in Figures 1 (a), 6(a) and 8(a), the supply and collection stages should be separated, ideally as far apart as possible, to allow air to cover the dynamic element. Although in Figures 1 (b), 6(b) and 8(b), the supply and collection stages are opposite each other, this is not essential. It should also be noted that there need not be a direct connection between the internal and external environments through dynamic insulation. Also whilst the supply and collection stages are generally shown as simple conduits that open into the inside or outside of the building, they may be ducted between the internal and external environments, as shown in Figure 11.

The embodiments illustrated above show applications of the invention only for the purposes of illustration. In practice the invention may be applied to many different configurations. For example, although in the above embodiments the invention has been described in the form of an integrated panel which is attached to a building to form a building envelope, it may be constructed from separate components which are fitted together in situ to form a building envelope. In this case, a kit of parts for making the dynamic insulation may be provided, together with instructions for assembling the dynamic insulation. In such a construction, for example, the exhaust of the first embodiment may be provided as an outlet in the inner cladding layer connected to a duct system which pipes the collected hot air out of the building. Moreover, although in the above embodiments the invention utilises an air permeable intermediate layer, other heat transfer layer arrangements are also possible. Also, the fan and control functions described may be located remotely, for example as part of a central air handling system, as practised with many HVAC installations.

Claims

1. Dynamic insulation for a building or structure, the dynamic insulation comprising an external surface and an internal surface; at least one heat transfer layer between the external and internal surface; a supply for supplying air to the heat transfer layer; a collector for collecting air that has passed the heat transfer layer and means for regulating pressure through the dynamic insulation.

2. Dynamic insulation as claimed in claim 1 , wherein the air is supplied to the dynamic insulation from the interior space or the exterior and/or exhausted to interior or exterior.

3. Dynamic insulation for a building or structure, the dynamic insulation comprising an external surface and an internal surface, at least one heat transfer layer between the internal and external surface, a supply for supplying air to the heat transfer layer; a collector for collecting air that has passed the heat transfer layer and an exhaust to allow air that has passed the heat transfer layer to be exhausted outside the building or structure. 4. Dynamic insulation as claimed in claim 3 comprising means for regulating pressure through the dynamic insulation.

5. Dynamic insulation as claimed in any of the preceding claims wherein the heat transfer layer comprises an air channel or an air permeable layer.

6. Dynamic insulation as claimed in claim 5 wherein when the heat transfer layer is an air permeable layer the supply and / or collector comprise a plenum.

7. Dynamic insulation as claimed in any of the preceding claims where air is supplied to the dynamic insulation from an interior space or an exterior space.

8. Dynamic insulation as claimed claim 1 or claim 3 comprising means for switching between two or more of: a first mode in which air is supplied to the dynamic insulation from the exterior and is directed to the interior; a second mode in which air is supplied to the dynamic insulation from the exterior and exhausted to the exterior and a third mode in which air is supplied to the heat transfer layer from the interior and exhausted to the exterior.

9. Dynamic insulation as claimed in any of the preceding claims comprising means for controlling magnitude and/or direction of airflow, optionally wherein the means for controlling comprises at least one fan and/or a damper and/or a valve and/or a grille.

10. Dynamic insulation as claimed in any of claims 1 , 2 and 4 or any claim dependent on claims 1 , 2 and 4, wherein the means for regulating pressure are operable to provide a pressure ratio where the pressure drop derived from the average airflow in the heat transfer layer is at least 50% of the pressure drop in the supply and/or collector; for example more than 60%; more than 70%; more than 80%; more than 90%, more than 100%, more than 120%, more than 140%, more than 160%.

1 1. Dynamic insulation as claimed in any of claims 1 , 2 and 4 or any claim dependent on claims 1 , 2 and 4, wherein the means for regulating pressure comprise at least one dimension of the insulation, selected from at least: an air channel dimension; a plenum dimension; a collector dimension; a supply dimension.

12. Dynamic insulation as claimed in any of claims 1 , 2 and 4 or any claim dependent on claims 1 , 2 and 4, wherein the means for regulating pressure comprise at least one constriction, optionally wherein the constriction is located in one or more of the supply, collector or heat transfer layer. 3. Dynamic insulation as claimed in any of the preceding claims wherein the heat transfer layer is an air channel and the supply and / or collector hydraulic radius is greater than the air channel hydraulic radius.

14. Dynamic insulation as claimed in any of the preceding claims wherein the heat transfer layer is an air channel and the supply and/or collector area, Aeon, is greater than the total air channel area per metre along the collection length, Ach_/m, selected from: Αα,ιι>30% / _m, Acoii>40% Ach _m, Acon>50% A**,,, ΑββΗ>βΟ

Ach/m. Acoii>70% Ach/m-

15. Dynamic insulation as claimed in any of the preceding claims wherein the heat transfer layer is an air channel and the supply and/or collector depth, dcon, is greater than the total air channel depth, den, selected from: d_∞n>80%d_Ch, d_∞ii>120% d_ch, dcoii 150% d*.

16. Dynamic insulation as claimed in any of the preceding claims wherein the heat transfer layer is an air channel and ratio of the air channel depth, d^, and air channel length, , is selected from: dch<2.5%l_Ch; dcn 2.0%l_Ch; .5% , d_ch<1.0%l_ch, or the heat transfer layer is an air permeable layer and the ratio of the plenum depth, d_p, and plenum length, l_p, is selected from: d_p<2.5%l_p; d_p<2.0%l_p; dp<15%l_p; d_p<1.0%l_p.

17. Dynamic insulation as claimed in any of the preceding claims wherein multiple heat transfer layers are provided, optionally separated by support posts.

18. Dynamic insulation as claimed in claim 17 where posts width, w_p, and heat transfer layer width, w_ch, are selected from: w_p<=200%w_ch, w_p<=150%w_ch, w_p<=100%Wch, w_p<=75%Wch, w_p<=50%w_ch.

19. Dynamic insulation as claimed in any of the preceding claims where the supply and/or the collection length, from the first point supplying to or collecting from to the entrance or egress to the dynamic insulation supply or collection area is selected from:

20. Dynamic insulation as claimed in any of the preceding claims where the supply and/or the collection pull length, leeway, from the first point supplying to or collecting from to the last point by a single entrance or egress to the dynamic insulation supply or collection area from:

lcoll2way^>=9-6^m-

21. Dynamic insulation as claimed in any of the preceding claims, wherein the inner and/or outer layer have an R-value greater than 0.2m²KW^"1; optionally greater than 0.3m²KW^"1; optionally greater than O^m'KW¹; optionally greater than 0.5m²KW¹; optionally greater than 0.6m² W^"1; optionally greater than 0.7m²KV\f 1; optionally greater than O.err^KW¹; optionally greater than 0.9m KW^'1; optionally greater than 1.0m²KW¹.

22. Dynamic insulation as claimed in any of the preceding claims wherein when the heat transfer layer is an air permeable layer, the R-value of the air permeable layer is greater than 0.2m²KW^"1; optionally greater than 0.3m²KW^"1; optionally greater than 0.4m²KW^"1; optionally greater than 0.5m²KW^'1; optionally greater than 0.6m²KW¹; optionally greater than 0.7m^zKW^"1; optionally greater than 0.8m²KW¹; optionally greater than 0.9m²KW^"1; optionally greater than 1.0m KW^" ¹; optionally greater than 1.25m²KW^"1; optionally greater than 1.5m²KW^"1; optionally greater than 1.75m²KW^"1; optionally greater than 2.0m²KW^"1.

23. Dynamic insulation as claimed in any of the preceding claims wherein the external surface and the interna/ surface form part of an integrated panel for fitting to a building or structure.

24. Dynamic insulation as claimed in claim 23, wherein the integrated panel has a U- value lower than 2Wm^" K^"1; preferably lower than 1.5Wm^"2K^"1; optionally lower than 1Wm^"2K^"1; optionally lower than 0.75Wm^"2K^"1; optionally lower than 0.5Wm^' K^"1; optionally lower than 0.4Wm^' K^'1; optionally lower than 0.3Wm^'2K^"1; optionally lower than 0.2Wm^"2K^'1.

25. Building envelope construction comprising dynamic insulation as claimed in any of the preceding claims, wherein the building envelope has a U-value lower than 2Wm^" K-¹; preferably lower than 1.5Wm^"2K^"1; optionally lower than 1Wm^'2K^'\- optionally lower than 0.75Wm^'2K^"1; optionally lower than 0.5Wm^'2K^'1; optionally lower than 0.4Wm^'2K^"1; optionally lower than 0.3Wm^"2K^~1; optionally lower than 0.2Wm-²K-¹.

26. Dynamic insulation as claimed in any of the preceding claims wherein one of the internal or external surfaces is part of the building or structure.

27. A building or structure that is fitted with dynamic insulation as claimed in any of the preceding claims.

28. A method for assembling dynamic insulation as claimed in any of the preceding claims comprising attaching insulation to a building or structure or forming the dynamic insulation as part of the building fabric.

29. A method as claimed in claim 28 wherein the building or structure forms part of the insulation.

30. A method as claimed in claim 28 where in the dynamic insulation is provided as an integral unit or panel for fitting to a building or structure.

31. A kit of parts for making dynamic insulation as claimed in claims 1 to 26.

32. A kit of parts as claimed in claim 31 including instructions for assembling the dynamic insulation.