Building vent

Abstract

A building vent 201 comprises a fresh air conduit 203 and a stale air conduit 206. The fresh air conduit receives the fresh air from a building exterior and discharges it into a building interior. The stale air conduit receives the stale air from the building interior and discharges it into the building exterior. The stale air conduit is located inside the fresh air conduit and heat is transferred between the fresh and stale air. A first stale air fan 209 draws the stale air into the stale air conduit. A second stale air fan 210 expels the stale air from the stale air conduit. The first and second stale air fans are controllable to maintain the pressure of the stale air within the stale air conduit at a higher air pressure than the building interior. For example, the second fan may be run a reduced flow rate relative to the first fan to increase the dwell time of the air in the stale air conduit and thereby increasing heat transfer from the stale air to the fresh air. At least one fresh air fan 211, 212 draws in the fresh air and expels it into the building.

Description

TECHNICAL FIELD

[0001] The present invention relates to a building vent. Certain embodiments relate to a vent that is installed in a window or a frame of a window and so may be referred to as a window vent or a window trickle vent. BACKGROUND

[0002] Increasingly, modern buildings including homes are built to higher construction standards including being more airtight than conventional buildings for energy efficiency reasons. However, provision must be made for ventilation to ensure that stale air does not build up. A building vent may be installed in one or more room to draw stale air from the building, to supply fresh air to the building or both.

[0003] A window trickle vent, often simply referred to as a trickle vent or ventilation slot, is a small, adjustable opening integrated into a window frame or frame profile. Its primary purpose is to allow a controlled flow of fresh air into a room while maintaining security and energy efficiency.

[0004] Figure 1 schematically illustrates a conventional window trickle vent. Window 101 is supported by window frame 102 (both shown in cross section). At least a portion of the window frame 102 is hollow. A first opening 103 and a second opening 104 each communicate with the hollow interior 105 of the window frame 102. For instance, opening 103 may be on the exterior of the building and opening 104 may be on the interior of the building. Air may be drawn to the building, expelled from the building or both through the opening 103, 104 and hollow interior 105 as indicated by bidirectional arrows 106. A regulator 107 may be provided on the interior opening 104. For instance, the regulator 107 may be manually operated to open or close (partially or fully) the opening 104 in order to regulate the flow of air through the trickle vent.

[0005] Trickle vents are commonly found in residential and commercial buildings and serve several important functions:

[0006] Ventilation: Trickle vents are designed to provide a continuous, low-level supply of fresh outdoor air into a room or building. This helps to improve indoor air quality by removing stale air and reducing the concentration of pollutants, odours, and excess moisture.

[0007] Moisture Control: They play a crucial role in preventing condensation on windows, particularly in colder seasons. By introducing a small amount of outdoor air, they help regulate humidity levels inside the room, reducing the likelihood of water droplets forming on the glass surface.

[0008] Energy Efficiency: Trickle vents are typically designed with features that allow users to adjust the airflow. This control enables occupants to manage the amount of air coming in, which can be particularly useful in energy-efficient buildings where minimizing heat loss is a priority.

[0009] Noise Reduction: Some trickle vents incorporate noise-reducing features to minimize the entry of outdoor noise, ensuring a quieter indoor environment.

[0010] Insect Protection: Many trickle vents are equipped with mesh screens or filters to prevent insects, dust, and debris from entering the room.

[0011] Trickle vents are typically positioned near the top of a window frame, either horizontally or vertically. They can be installed through an aperture in the window frame (or in some cases through the glass) or they can be installed adjacent to the window frame in the building aperture. While the term “window trickle vent” is often used, they may be installed instead in or adjacent to a door or doorframe. They can be manually adjusted to control the amount of airflow, usually through a sliding mechanism or a rotating cover. Some modern trickle vents may also be motorized and controllable through smart home systems for added convenience.

[0012] In summary, a window trickle vent is a discreet and functional component integrated into window frames to provide controlled ventilation, moisture control, and energy efficiency while maintaining security and comfort within a building. It will be appreciated that similar considerations, features, and benefits apply equally to building vents installed through other building structures, notable a wall of the building. Such a wall mounted building vent may be functionally similar but physically different owing to the greater distance they must traverse between the building interior and the building exterior.

[0013] Building vents such as window trickle vents serve an important purpose in providing ventilation and maintaining indoor air quality, but they can also have some drawbacks and potential problems:

[0014] Drafts: Building vents, if not properly sealed or adjusted, can sometimes allow drafts of cold air to enter the room. This can make the room less comfortable, especially in colder weather, and may increase heating costs.

[0015] Energy Loss: When not in use or when left open excessively, building vents can contribute to energy loss by allowing conditioned indoor air to escape and unconditioned outdoor air to enter, which can increase heating or cooling costs.

[0016] International patent application publication WO-2008 / 037085-A1 discloses a trickle vent incorporating an automatically controlled movable damper or multiple dampers to control the volume of fresh air entering a building. An actuator receives a control signal from the heating and ventilation system of the building to control the opening and closing of the damper or dampers. The trickle vent further includes heating element to condition the fresh air prior to entry into the occupied space. The trickle vent may be mounted in an opening in an exterior wall of the building.

[0017] It is an aim of certain examples of the present invention to solve, mitigate or obviate, at least partly, at least one of the problems and / or disadvantages associated with the prior art. Certain examples aim to provide at least one of the advantages described below. BRIEF SUMMARY OF THE INVENTION

[0018] According to a first aspect of the present invention there is provided a building vent comprising: a fresh air conduit configured in use to receive fresh air from a building exterior and to discharge the fresh air to a building interior; a stale air conduit configured in use to receive stale air from the building interior and to discharge the stale air to the building exterior, the stale air conduit being arranged relative to the fresh air conduit such that heat is transferred between fresh air and stale air; a first stale air fan or pump configured to draw stale air into the stale air conduit; and a second stale air fan or pump configured to expel stale air from the stale air conduit; wherein the first and second stale air fans or pumps are controllable to maintain the pressure of stale air within the stale air conduit at a higher air pressure than the building interior.

[0019] The first and second stale air fans or pumps may be controllable such that the flow rate of stale air into the stale air conduit exceeds the flow rate of stale air out of the stale air conduit.

[0020] The building vent may further comprise at least one fresh air fan or pump to draw fresh air into or expel fresh air from the fresh air conduit.

[0021] The stale air conduit may be located inside the fresh air conduit along at least part of its length. As well or instead, the fresh air conduit and the stale air conduit may follow an adjacent sinuous path along at least part of their lengths.

[0022] The building vent may further comprise a controller configured to control the or each fan or pump in response to a signal received from: one or more environment sensor incorporated into the vent; a remotely located environment sensor; a user interface incorporated into the vent; a remotely located user interface; or a building heating or ventilation system controller.

[0023] The building vent may further comprise a heater configured to heat fresh air within the fresh air conduit.

[0024] According to a second aspect of the present invention there is provided a building comprising a window, door, wall, or other structural component incorporating a building vent as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Examples of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a partial cross section of a window frame including a conventional window trickle vent; Figure 2 is a cross section view of a building vent according to an embodiment of the present invention; and Figure 3 is a schematic diagram of a building ventilation system including a plurality of vents according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Turning now to figure 2, this schematically illustrates a building vent 201 according to an embodiment of the present invention. The building vent 201 is not illustrated to scale and it will be appreciated that its shape and physical configuration may vary widely from that illustrated. Figure 2 serves to illustrate certain functional aspects of the building vent. The building vent 201 of figure 2 is specifically illustrated as a window vent (and may be referred to also as a window trickle vent or active trickle vent, as will become apparent from the following description). Specifically, the building vent 201 is shown in an installed position upon a window 202 (either the frame or the glass). Particularly, portions of the building vent 201 (described below) extend through an aperture 214 within the window frame or glass. It will be appreciated that there may be multiple apertures 214 or the dimensions of the aperture 214 may vary (or both) according to the required throughput of air.

[0027] The building vent 201 comprises a fresh air conduit 203 extending through the window aperture 214 between a fresh air inlet 204 positioned in use on the exterior of the building and a fresh air outlet 205 positioned in use on the interior of the building. The fresh air conduit 203 is configured in use to receive fresh air from the building exterior and to discharge the fresh air to the building interior.

[0028] The building vent 201 further comprises a stale air conduit 206 extending through the window aperture 214 between a stale air inlet 207 positioned in use on the interior of the building and a stale air outlet 208 positioned in use on the exterior of the building. The stale air conduit 206 is configured in use to receive stale air from the building interior and to discharge the stale air to the building exterior.

[0029] The stale air conduit 206 is arranged relative to the fresh air conduit 203 such that heat is transferred between fresh air and stale air. Suitably this may comprise the fresh air conduit 203 and the stale air conduit 206 being formed from concentric tubes (with the stale air conduit 206 being received inside the fresh air conduit 203 or vice versa). This is schematically illustrated in figure 2 and the appropriate connections between the conduits and the inlets and outlets are not illustrated. As well or instead a heat exchanger arrangement between the conduits may be achieved by arranging the conduits relative to one another in a sinuous arrangement to increase the surface area between the two conduits. This is shown on the right hand side of figure 2 (within the room or building) but it could equally be on the outside of the building or both. Numerous heat exchange configurations will be apparent to the skilled person based on their knowledge of related ventilation systems, such as Mechanical Ventilation with Heat Recovery (MVHR).

[0030] According to an embodiment of the present invention the building vent is active insofar as a first stale air fan or pump 209 is configured to draw stale air into the stale air conduit. A second stale air fan or pump 210 is configured to expel stale air from the stale air conduit. That is, the building vent is not reliant on a pressure differential between the interior and the exterior of the building to drive airflow: stale air may be extracted from the building upon demand. Furthermore, according to an embodiment of the present invention, the first and second stale air fans or pumps 209, 210 are controlled so that stale air within the stale air conduit is maintained at a higher air pressure than the building interior. For instance, the second fan or pump 210 may be run at a slightly reduced flow rate relative to the first pump or fan 209 such that the stale air dwell time within the stale air conduit 206 is increased. This flow rate differential serves to slightly pressurise the stale air in the stale air conduit 206. The present inventor has recognised that by increasing the stale air dwell time within the conduit 206 the amount of heat transferred from the stale air to the fresh air may be increased.

[0031] Figure 2 further illustrates fresh air pumps or fans 211,212 for driving fresh air though the fresh air conduit 203. The fresh air pumps or fans are not essential: the flow of fresh air may be driven solely by the expulsion of fresh air. Alternatively, it may be that only a single fresh air fan or pump is provided to control the volume of fresh air delivered. Where a pair of fresh air fans or pumps are provided then they may be run at different flow rates to increase the dwell time of fresh air within the conduit to further increase the exchange of heat between stale air and fresh air.

[0032] Figure 2 further illustrates an insulation or packing material 213 provided about the air conduits. It will be appreciated that further components such as housing to contain the above described parts may be provided.

[0033] In some embodiments the active components of the building vent (that is the stale air fans or pumps, and if provided the or each fresh air fan or pump) may be actively controlled to control the volume of fresh air delivered and stale air expelled. The building vent may include a controller (not illustrated) arranged to control each active component. The fans or pumps may be electrically driven. Control may be as simple as providing a manually activated switch upon the vent for a user to manually turn it on or off. There may be provision for manual control of fan or pump speed to control air flow rate.

[0034] In other embodiments the vent may include one or more sensor (such as to sense temperature, pressure, humidity, or any other environmental parameter within the building) such that the controller may automatically control the active vent components to maintain a desired environment within the building. In other embodiments, those sensors may be remotely provided and communicated (via a wired or wireless connection) such that the controller can control the vent operation. In other embodiments the vent may be “dumb”. A controller may be configured to receive control instructions for vent operation from some external device or system (for instance, a remotely located control panel or a wider building ventilation system (described below in connection with figure 3). Power for the controller and the fans or pumps may be provided by a mains electricity connection, a battery or a solar panel provided on the exterior portion of the vent. In some cases, the vent may operate in an autonomous mode for part of the time if no control signal is received from a building ventilation system, and in a controlled mode when control signals are received.

[0035] The building vent may be provided in two parts: an interior portion and an exterior portion which may be coupled together through the aperture 214. Suitably, this may allow the vent to be retrofittable to an existing window through which an aperture 214 has been bored. Although a single aperture is shown, it is possible that multiple apertures can be used under the same principle. Of course, in other embodiments the building vent may be provided within a window frame in advance of the installation of the window frame within the building. For some exemplary vent configurations, a 20 mm diameter aperture may suffice to provide an acceptable supply of fresh air and exhaust of stale air, when the vent is actively driven. The size of the aperture will be selected according to the required performance specifications. For instance, a 20 mm diameter may not provide adequate ventilation in passive environment. In such a situation, a number of such apertures measuring 20 mm diameter may be employed to ventilate passively to provide a much higher level of ventilation.

[0036] Suitably, one or more fan or pump may be driven by a motor, for instance a stepper motor, allowing for ON / OFF activation and speed or flowrate control.

[0037] When operated autonomously, the vent may operate to optimise one or more sensed environmental parameter within the building or to balance internally and externally sensed parameters (temperature / pressure / etc.). This may be achieved through the use of sensors positioned on each side of the window or wall.

[0038] Turning now to figure 3, this illustrates a building ventilation system including a plurality of building vents according to an embodiment of the present invention. The building ventilation system includes a controller 301 which is arranged to control a plurality of ventilation system components. In one embodiment the controller may control a Positive Input Ventilation (PIV) device 302. A PIV is a type of mechanical ventilation system used to improve indoor air quality and control moisture levels within a building, typically a residential property. PIV systems are primarily designed to combat issues related to condensation, dampness, and poor air circulation. They work by introducing fresh, filtered air into the building while simultaneously expelling stale or moisture-laden air through positive pressure delivered to the building. The controller 301 may further control a plurality of building vents 303 such as illustrated in figure 2. These may be provided in different rooms within the building. The vents 303 may be controlled synchronously or individually. For instance, the vents may be activated one by one such that fresh air delivered by the PIV is used to replace stale air in each room in turn. It will be appreciated that where building vents according to embodiments of the present invention are used in combination with a source of fresh air such as a PIV, each vent may be configured to expel a greater volume of stale air than the fresh air it draws in to ensure a flow of fresh air through the building. This may suitably be achieved through control of the respective fans or pumps within the vent.

[0039] It will be appreciated that for the system of figure 3 this may comprise an add on to a smart heating or ventilation system, in addition to other system components such as remotely controlled thermostatic radiator valves.

[0040] In some embodiments the building vent may include a heater or heating element configured to provide supplementary heat to fresh air drawn into the building. Suitably, the heater may heat the air within the fresh air conduit. This may be after the heat exchange from the stale air has taken place. To allow time to heat the fresh air, the heater may be positioned inside the vent before the fresh air is expelled into the building.

[0041] The main parts of the building vent can be set within a UPVC shell or other suitable material with insulation materials to suit the injection of warmed air and the ejection of stale air. This may include various designs for the shape, colour, and footprint as necessary in order to abide by architectural requirements or local building concerns.

[0042] There may also be provision of local control so that the best speeds and air intake or outtake are selected. This may allow end user selection. The present invention also encompasses for a device that may have no controls and adapts or can be simply preset to specific parameters during manufacturing.

[0043] It will be understood that for a given room to be ventilated by a building vent according to the present invention, assuming for the moment that the room is a closed volume, the room volume may be readily calculated. The time to replace the full volume of stale air within the room may be specified. As an example, this may be 30 minutes. From these two parameters, the required aperture size and fan speeds may be readily calculated to meet these two constraints. Alternatively, the air displacement or air volume per unit time for a given fan will be specified by the manufacturer. From this, the time taken forthat fan to change the air in the room can be calculated to determine whether it meets the desired time constraint. Note that this calculation may hold true for a house with an internal to external pressure differential of 50 Pascal, which may apply to a passive houses, as an example. There are ample choices available for fans which can allow for the displacement of 30m3 (room sample volume of 4X3X2.5 m3) of air within a 30 minute time window over the trickle vent aperture(s).

[0044] A fan or a set of fans (two or more) between the outside and internal side of the vent could outline a pressure differential and then output or demand a given speed from the fan or fans to yield the change within the desired air exchange time.

[0045] When fans are used as outlined above, there are some measurements that need obtaining either empirically or theoretically. This is also mitigated above through the example given; however, it can help for optimisation and calibration against the space used. Bearing in mind how much air needs displacing from the room to / from the outside, yields the actual parameters to use in this instance are: • internal pressure (P1) • external pressure (P2) • aperture diameter or area (20 mm or so) • mass flow rate through vent conduits (F1) • airspeed (V)

[0046] The air speed is outlined by the fan or fans. This yields the flow rate and from then on, its efficiency with respect to the pressure differential P1-P2.

[0047] Once the air flow is determined and the time taken for changing the room air (as mentioned for a passive system), it is a matter of replacing some numbers with variables and drawing graphs.

[0048] For example, P2 may be expressed as an unknown and a graph drawn of the time it takes to change the air with respect to P2. Other variables may be used similarly.

[0049] The fan speed depends on P1-P2 and the convergence point for this controller is essentially:

[0050] Input: P1, P2, Aperture, medium where the air goes through, T1, T2

[0051] Output 1: Fan speeds (in the control loop)

[0052] Output wanted in the living space: Full air displacement in less than 30 minutes.

[0053] When two fans are used in counter flow the air residence in the vent conduits may increase. This allows for the thermal capacity of the pipes of the vent conduits which are designed so that there is exposure to room temperature when needed and not when not needed in another context. This allows for input air to have a temperature closer to that of the inside of the room and minimise heat loss. The stale air encapsulates (through design) the input air and henceforth this functions as a small heat exchanger.

[0054] The heat transfer between say a copper pipe and the circulating air and its speed can be outlined. Using the air heat capacity and relevant volume / density allows for such straight calculation.

[0055] There may be as much as four fans (two fans in the stale air flow path and two fans in the fresh airflow path).

[0056] In some embodiments the fan speeds and positioning are selected to minimise noise. In some cases, the fan noise should be kept below 42db especially for fans inside the room or living space.

[0057] In some embodiments an advantage in using a building vent is that it may be retrofitted and easily installed. A two-part system where two parts plug into each other across the fabric of either a window or wall may be used. Power may be drawn either through solar energy harvesting (solar cell outside) or using main power from the inside of the room (low voltage for safety). Ordinary low cost power adaptors can be used.

[0058] Throughout this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers, or steps. Throughout this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Throughout this specification, the term “about” is used to provide flexibility to a range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and can be determined based on experience and the associated description herein.

[0059] Features, integers, or characteristics described in conjunction with a particular aspect or example of the invention are to be understood to be applicable to any other aspect or example described herein unless incompatible therewith. All of the features disclosed in this specification, and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing examples. The invention extends to any novel feature or combination of features disclosed in this specification. It will also be appreciated that, throughout this specification, language in the general form of “X for Y” (where Y is some action, activity or step and X is some means for carrying out that action, activity or step) encompasses means X adapted or arranged specifically, but not exclusively, to do Y.

[0060] Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0061] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. 16 04 24

Claims

1. A building vent comprising:a fresh air conduit configured in use to receive fresh air from a building exterior5 and to discharge the fresh air to a building interior;a stale air conduit configured in use to receive stale air from the building interior and to discharge the stale air to the building exterior, the stale air conduit being arranged relative to the fresh air conduit such that heat is transferred between the fresh air and the stale air;10 a first stale air fan or pump configured to draw the stale air into the stale airconduit; anda second stale air fan or pump configured to expel the stale air from the stale air conduit;wherein the first and second stale air fans or pumps are controllable to maintain15 the pressure of the stale air within the stale air conduit at a higher air pressure than the building interior.

2. A building vent according to claim 1, wherein the first and second stale air fans or pumps are controllable such that the flow rate of the stale air into the stale air conduit20 exceeds the flow rate of the stale air out of the stale air conduit.

3. A building vent according to claim 1 or claim 2, further comprising at least one fresh air fan or pump to draw the fresh air into or expel the fresh air from the fresh air conduit.

254. A building vent according to any one of the preceding claims, wherein the stale air conduit is located inside the fresh air conduit along at least part of its length; orwherein the fresh air conduit and the stale air conduit follow an adjacent sinuous path along at least part of their lengths.

305. A building vent according to anyone of the preceding claims, further comprising a controller configured to control the or each fan or pump in response to a signal received from:one or more environment sensor incorporated into the vent;35 a remotely located environment sensor;a user interface incorporated into the vent;a remotely located user interface; orCXIa building heating or ventilation system controller.

6. A building vent according to anyone of the preceding claims, further comprising a heater configured to heat the fresh air within the fresh air conduit.

7. A building comprising a window, door, wall, or other structural component incorporating a building vent according to any one of the preceding claims.

Images