Active air insulation for greenhouses

Abstract

An active air insulation structure can be made with a plurality of exterior walls connected with one another for defining the structure and an interior space therein. Each of the exterior walls further can comprise double layered walls, having an outer layer exposed to an outside or ambient environment, and an inner layer exposed to the interior space, the outer and inner wall defining an open air cavity therebetween. A fluid can be placed within the open air cavity and an airflow forcing device fluidly connected to the open air cavity can be used to create a circulation air flow, resulting in active air insulation. A fluid conditioning device fluidly connected to the airflow forcing device can condition the fluid flowing within the open air cavity.

Description

[0001] ACTIVE AIR INSULATION FOR GREENHOUSES

[0002] Field

[0003] Embodiments of the present invention relate to a method to insulate an air space enveloped by a building structure, and more specifically, a method of using active air insulation for insulating building agricultural structures, such as greenhouses.

[0004] Background

[0005] Atraditional method of insulation typically involves a dual wall structure, and a space captured between the dual walls being filled with an insulative material or media, such as a rigid or a fibrous materials. This insulative media functions as a thermal barrier for preventing heat loss from an inside atmosphere or environment to an outside atmosphere or environment.

[0006] This type of traditional insulation method is commonly known as “passive” insulation, as the insulative properties are fixed upon installation. A disadvantage of passive insulation is that over time, its insulative capabilities deteriorate, such to a point that the insulative media will have to be rebuilt to re-instate its insulative capacity.

[0007] In cold climates, an inside atmosphere of a structure is typically heated to keep comfortable for things that are inside of the structure, whether it is for people in a building or for plants in a greenhouse. The quality of the insulative media determines the quantity of heat required to heat up the inside environment to maintain a comfortable temperature. When outside temperatures decrease in colder climates, the insulation capacity of the passive insulation is often reduced due to the condensing effect within the interior of the insulative media. This results in more heat required to keep the inside environment warm. However, there is no way to “adjust” the insulative capability with the above mentioned passive insulation method. Thus, in extreme weather conditions, the cost for heating or cooling the inside space of the building structure is very high.

[0008] In agricultural applications, traditional greenhouses often use this passive form of insulation, along with relying on the principles of the Greenhouse Effect, which occurs when energy-rich infra-red spectrum (in the form of sunlight) is trapped inside a greenhouse by transparent walls thereof. The heating effects of the Greenhouse Effect, along with passive insulation allow greenhouse operators to reduce their operating costs.

[0009] However, in colder climates, the difference in temperature measured between the outside environment and the inside interior of a greenhouse can be at least 10 to 15°C, and thus any heat provided by the Greenhouse Effect may not be sufficient to maintain an interior temperature for optimum plant growth.

[0010] Summary

[0011] A volume of air trapped between the dual walls of a typical double wall structure can be used for “active” insulation. By replacing rigid or fibrous materials used as the insulative media in passive insulation systems, with a fluid insulative media, such as air, the air trapped within the double wall structure can be “conditioned” by an Active Insulation Air Handling Unit (AIAHU). The AIAHU can condition the air, and through the use of ducting, fluidly connect the conditioned air to the rest of greenhouse. Advantageously, a greenhouse using active conditioned air for insulation can provide greater and more efficient heating of an interior of a building structure, without reliance on additional heating sources.

[0012] In a broad aspect of the invention, an active air insulation structure comprises a plurality of exterior walls operatively connected with one another for defining the structure and an interior space therein, each of the exterior walls further comprising double layered walls, having an outer layer exposed to an outside environment, and an inner layer exposed to the interior space, the outer and inner wall defining an open air cavity therebetween, a fluid for providing insulation within the open air cavity, an airflow forcing device fluidly connected to the open air cavity, for creating a circulation air flow, tubing for fluidly connecting the airflow forcing device with the open air cavity, and a fluid conditioning device fluidly connected to the airflow forcing device for conditioning the fluid flowing within the open air cavity. Brief Description of the Drawings

[0013] Figure 1 is a diagram of an embodiment of the present invention, illustrating an active air insulation system comprising an air-tight double walled building structure, and an active insulation air handling unit (AIAHU);

[0014] Figure 2 is a schematic representation of an embodiment illustrating the active insulation system as applied to a greenhouse;

[0015] Figure 3 is a schematic representation of the AIAHU in accordance to Fig. 2;

[0016] Figure 4 is a schematic representation of the double wall structure in accordance to Fig.1 ; and

[0017] Figure 5 is a schematic representation of an embodiment of the present invention, illustrating a thermal electric conversion device.

[0018] Description

[0019] With reference to Figs. 1 and 2, an active air insulation system 10 for a building, or for a greenhouse, can comprise a plurality of exterior walls operatively connected to one another for defining a structure, and an interior space therein. Each of the plurality of exterior walls can comprise double layered wall 20 having an outer layer 22 and an inner layer 24 defining an open air cavity 30 therein. The open air cavity 30 can be adapted to receive a conditioned fluid 40, such as hot and dry air flow, or cool and wet air flow from a fluid conditioning device, such as an Active Insulation Air Handling Unit (AIAHU) 50. The AIAHU 50 functions to heat up or cool down air passing therethrough, and also to dry or wet (ie. humidify) air passing therethrough and to force an air flow AF through a chamber cavity 60 from an outlet manifold 70, and at the same time, suck in a returned air flow through an inlet. The AIAHU promotes a circulation air flow CAF through the chamber cavity 60. A volume exchange speed can be adjusted by an air flow forcing device 80, which, in embodiments, can be a separate piece of hardware or can be incorporated into the AIAHU 50, as seen in Fig. 2.

[0020] As shown in Fig. 3, the AIAHU 50 can consists of the functional components but are not limited to the following: a heating device 90 and a dryer device 100 for a winter set-up or set-up for colder climates, and a cooling device 110 and a humidifier device 120 for a summer or warmer climate set-up.

[0021] In embodiments, and with reference to Fig. 2, the heating device 90 can be either electrical or propane or natural gas fueled; the dryer device 100 can be either a desiccant moisture absorption device, or a condensate trap or a filtration device or any other de-moisturizing or dehumidifying device to help remove water content in the active insulation air volume that is circulating within the chamber cavity.

[0022] In embodiments, the cooling device 110 can be either any air conditioning system or vaporizing cooler fan; the humidifier or humidifying device 120 can be either ultrasonic or damp-filter fan evaporation escalator or steam maker.

[0023] The air flow forcing device 80 can be either or fan blower 130 or a light duty air compressor 140 to generate the air flow AF with an appropriate pressure, so as not to cause air leaks or the overload the double-wall envelope, and maintaining an air-tight seal or isolation.

[0024] The AIAHU 50 can comprise a control module or a controller (not shown) and can be programmed by loT software and hardware, which can automatically adjust the AIAHU operational parameters, such as air flow speed, air temperature and moisture content for ensuring constant temperatures inside the building structure.

[0025] With reference to Figs. 2 and 4, and in embodiments, the AIAHU 50 can be engineering-designed and installed to fluidly connect to the air trapped within the open air cavity 30 between the double walls 20, such that hot, dried and forced air can flow from the AIAHU 50 to a top 160 of the structure 170 and create a downflow of conditioned fluid 40 within the double wall chamber space or open air cavity 30. As the conditioned air travels, the conditioned air can lose its heat energy to the surrounding environment, including portions of the double wall 20 and an interior space 180 of the structure 170, heating the interior space 180 of the structure to assist in temperature management thereof. As the downflow of the conditioned air continues, it will continue to lose its heat energy, and once the conditioned air reaches a bottom 190 of the double wall 20, it can flow into a return pipe 200 connected to the AIAHU 50. In embodiments, the return pipe 200 can be fluidly connected to a suction inlet 210 of the AIAHU 50. The return air can then be conditioned again by the AIAHU 50 and then recirculated. This permits the insulation air volume to be circulated all the time.

[0026] In embodiments, the circulation of air flow can be reversed, with the air flowing from the AIAHU 50, through the outlet manifold 70, through the return pipe 200, and upwardly through the open air cavity 30, towards the top 160 of the structure.

[0027] The AIAHU 50 can be designed and adapted to adjust for a desire or appropriate insulation air pressure, temperature, flow velocity and humidity (dryness) to achieve an optimal and practical thermal diffusivity of this insulation air volume. Controlling the thermal diffusivity of the insulation, which is inversely proportional to its insulation capability, can improve the preventing of the heat loss from the interior space 180 of the structure inside to the surrounding external environment, thus less energy is required to maintain a temperature within the interior space 180.

[0028] In embodiments, during colder temperatures, such as winter, the AIAHU 50 can be adjusted to provide the hot-dry-forced insulation air in the double wall space to prevent the heat-loss from inside to the outside.

[0029] In embodiments, during warmer times of the year, such as summer periods, the AIAHU 50 can be adjusted to provide a cool, wet, forced air to prevent heat penetration from outside to the inside. The cool, wet air can be conditioned by the AIAHU 50, and can be employed to reduce or keep the inside environment, such as the interior space 180, cooler than the outside environment.

[0030] In embodiments, a total volume of the open air cavity 30, throughout the entirety of the structure can be relatively very small in comparison to a total volume of the interior space 180. Therefore, a heat quantity required to compensate for heat loss, to maintain a comfortable temperature inside the structure with active air insulation, will be very minimal in comparison to the same space using traditional passive insulation.

[0031] As shown in Fig. 1 , the open air cavity 30 of the double walled exterior wall 20 can be fluidly connected to the AIAHU 50. In embodiments, a plurality of tubing 220 can be used to fluidly connect the double walled exterior wall and the air heater or heating device 90 together. In embodiments, the air heater 90 can further comprise the air dryer or drying device 100 for removing any moisture from the conditioned fluid. In other embodiments, the air heater 90 can further comprise a humidifier or humidifier device 120 for increasing a humidity of the conditioned air.

[0032] In embodiments, and as shown, the double walled exterior wall 20 can be an air-tight double-layer wall made of high light-transmission material. Such materials allow a greenhouse to combine the advantages of using direct sunlight and artificial light, for optimizing plant growth and energy cost savings. In embodiments, the double wall exterior walls can be supported by pre-fabricated steel structures, or in other embodiments, can be supported by pre-fabricated composite structures.

[0033] Although not shown, the dimensions of the structure, such as a width, a height, and a shape, can be customized for specific implementations and applications thereof.

[0034] Further, and in embodiments, the active conditioned air, as opposed to the reliance of passive fibre air, in the open air cavity 30 or insulation gap space of the double wall exterior wall 20 can improve air heat diffusivity and thermal loss control, which consequently improves the temperature control inside the greenhouse with much less energy consumption and cost. Applicant has coined the term active air insulation, as the insulative material is not fibrous materials as known in the art, but a fluid, such as air, and the air is actively moved or circulated through the open air cavity between each of the layers of the double wall.

[0035] In embodiments, an active conditioned air system allows a farmer to use dry, heated and forced air in the winter, to keep temperatures relatively high, and wet, cooled and forced air in the summer to keep the temperature in the greenhouse cool.

[0036] With specific reference to Fig. 2 and in embodiments, a greenhouse or the building can have a dome-roof shape for increasing air circulation inside the greenhouse and creating the homogenous air quality environment.

[0037] In embodiments, and as discussed above, the double wall 20 of the structure can be made from transparent materials, such as glass or transparent or translucent plastic. Such materials allow the transmission of light therethrough, such that active air insulation still can act in combination with the solar energy, which helps to reduce the energy needs for the above-mentioned AIAHU 50. In embodiments, this can also provide natural sunlight to reduce the cost for the artificial lighting for growth in the winter.

[0038] In embodiments, and as shown in Fig. 3, a volume of air trapped between dual transparent walls of a double-wall structure can be used not only for “active” insulation as described above, but also for capturing potential energy. In embodiments, Applicant has found that the system can create a temperature difference up to between 40°C ~ 50°C, depending on an intensity of sunlight shining on the structure. This difference in temperature can be sufficient for absorbing and harvesting by known methods, such as thermo-electrical conversion or air-to-air or air-to-liquid heatexchangers to provide as a new renewable energy supply source.

[0039] With reference to Fig. 4, and as shown, in embodiments, the volume of air can be trapped or isolated between the dual transparent walls of a typical AAI greenhouse double-wall structure for active insulation. Potential energy available in the trapped volume of air can be harvested using known methods, such as a low temperature range thermal-electric conversion device

[0040] Fig. 1 illustrates an embodiment of the present invention, showing an active air insulation system comprising air-tight double walled structures. As shown, an interior volume or cavity between is created between the double wall structure. As shown, the double green house effect (“DGE”) is illustrated therein.

[0041] As shown, the outer layer 22 of the double wall 20 can be exposed to sunlight, which initiates the DGE within the interior space of the structure. Potential energy, in the form of heat from the sun (ie. solar heat) can be captured and can be intensified within the interior space. This process can cascade unabaded, resulting in rising temperatures within the interior space.

[0042] In embodiments, and as shown in Fig. 2, the DGE energy potential can be absorbed and harvested in the form of potential electrical power by a low temperature range thermal-electric conversion device 230. As shown, a cold side 240 of the device 230 can be in contact with the ambient surroundings while a hot side 250 can be in contact with the interior space 180 of the structure. The resulting difference in air temperature across the device 230 will result in the device 230 saving potential energy in the form of electrical energy for later use.

Claims

Claims:1 . An active air insulation structure comprising: a plurality of exterior walls operatively connected with one another for defining the structure and an interior space therein, each of the exterior walls further comprising double layered walls, having an outer layer exposed to an outside environment, and an inner layer exposed to the interior space, the outer and inner wall defining an open air cavity therebetween; a fluid for providing insulation within the open air cavity; an airflow forcing device fluidly connected to the open air cavity, for creating a circulation air flow; tubing for fluidly connecting the airflow forcing device with the open air cavity; and a fluid conditioning device fluidly connected to the airflow forcing device for conditioning the fluid flowing within the open air cavity.

2. The active air insulation structure of claim 1 , wherein the fluid conditioning device comprises a heating device.

3. The active air insulation structure of claim 1 or 2, wherein the fluid conditioning device comprises a dryer device.

4. The active air insulation structure of claim 1 , 2, or 3, wherein the fluid conditioning device further comprises a cooling device.

5. The active air insulation structure of any one of claims 1 to 4, wherein the fluid conditioning device further comprises a humidifier device.

6. The active air insulation structure of any one of claims 1 to 5, wherein the fluid conditioning device further comprises a blower, permitting constant flow of conditioned fluid throughout the structure.

7. The active air insulation structure of any one of claims 1 to 6, wherein the fluid conditioning device further comprises an outlet manifold having an chamber cavity.

8. The active air insulation structure of claim 1 , wherein the circulation air flow further comprises a downflow of conditioned fluid, beginning from a top of the structure, and flowing downwardly and directed towards the fluid conditioning device by a return pipe.

9. The active air insulation structure of claim 1 , wherein the circulation of air flow further comprises an upward flow of conditioned fluid, beginning from the fluid conditioning device, flowing upwardly towards a top of the structure.

10. The active air insulation structure of claim 8 or 9, wherein the return pipe is fluidly connected to the chamber cavity of the fluid conditioning device by way of a suction inlet.11 . The active air insulation structure of any one of claims 1 to 10, further comprising a thermal-electric conversion device for harvesting potential energy in the form of the thermal difference between the ambient environment and the interior space of the structure into potential electrical energy.

12. The active air insulation structure of any one of claims 1 to 11 , further comprising pre-fabricated steel structures or pre-fabricated composite structures.

13. The active air insulation structure of any one of claims 1 to 12, wherein a width, height, and shape of the structure can be variable, depending on implementation thereof.

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