GB2546530A

GB2546530A - Elevator energy recovery system

Info

Publication number: GB2546530A
Application number: GB1601181.9A
Authority: GB
Inventors: Sankey Tim
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-01-22
Filing date: 2016-01-22
Publication date: 2017-07-26
Also published as: GB201601181D0

Abstract

An elevator (lift) system comprises an elevator 3 movable within an elevator shaft 1, typically between floors of a building. An airflow turbine 11, 13 is driven by the air flow caused by movement of the elevator 3. The turbines 11, 13 may be bi-directional turbines, or there may be separate turbines for flow in opposite directions (figure 2). Turbines may be positioned in vents to be driven by airflow to or from the lift shaft, or they may be installed in a duct 25 in the elevator car 3 to be driven by air flow from a leading surface to a trailing surface of the car.

Description

ELEVATOR ENERGY RECOVERY SYSTEM

The present invention relates generally to an elevator energy recovery system and a method of recovering waste energy from movement of an elevator and tinds particular, although not exclusive, utility in buildings.

In conventional elevator systems (also known as 'lifts'), an elevator is moved within an elevator shaft, typically between floors of a building. In moving within the elevator shaft, the elevator must push air within the shaft out of its way, and similarly move air into the space it has just vacated. In an enclosed elevator shaft, the air must flow around the elevator from one side to the other; however, this can cause significant resistance to motion.

One solution would be to ventilate the elevator shaft, for instance by placing the elevator shaft on the exterior of a building, and/or having one or more sides of the elevator shaft open to the exterior environment. This is the case in external elevators.

However, for a variety of reasons (such as protecting the elevator system from external environmental conditions), it is often desirable to have an elevator shaft located entirely within a building. Thus, any venting of the elevator shaft must be achieved by providing relatively small cross-sectional area vents (compared to the elevator shaft).

In a substantially incompressible fluid (such as water), energy due to movement of an elevator would be imparted to the fluid as kinetic energy, and this energy could not be extracted from the water without increasing the energy burden on the elevator movement mechanism. However, using a compressible fluid (such as air), energy due to movement of the elevator is imparted to the fluid as a combination of kinetic energy and potential energy due to the compression. This potential energy may be extracted from the air by expanding the air through an expansion turbine, or other power-take-off system. The degree to which the air is compressed depends largely on the size of the external vents, and not on any back-pressure created by a turbine in-line with the vents.

According to a first aspect of the present invention, there is provided an elevator energy recovery system, comprising a power-take-off system configured to convert airflow within an elevator shaft into usable energy.

As an elevator ascends and descends within an elevator shaft, air is displaced by the elevator and pushed back and forth past the power-take-off (PTO) system that converts airflow within the elevator shaft into usable energy.

The power-take-off system may be configured to generate electricity.

The power-take-off system may comprise a turbine. The turbine may comprise an impulse turbine, a reaction turbine, or a mixed impulse-reaction turbine. The turbine may comprise an aerofoil-powered generator, or some other form of turbine.

The turbine may comprise a bidirectional turbine. That is, the turbine is configured to rotate in a first rotational sense independent of the direction of air incident thereon.

The turbine may be configured to rotate about an axis substantially parallel to airflow incident thereon. That is, the turbine may be of the horizontal axis wind turbine type; however, the orientation of the axis may be at an angle to the horizontal if the airflow is non-horizontal. For instance, the bidirectional turbine may be a Wells turbine or a Hanna Turbine (described in US patent US8358026), such that the turbine always spins the same direction regardless of the direction of airflow (e.g. up or down the elevator shaft).

The turbine may be configured to rotate about an axis substantially perpendicular to airflow incident thereon. That is, the turbine may be of the vertical axis wind turbine type; however, the orientation of the axis may be at an angle to the vertical if the airflow is non-horizontal.

The turbine may comprise a starter, for initiating rotation of the turbine. The starter may be, for instance, an electric motor, or a mechanical linkage coupled to an elevator movement mechanism for initiating rotation of the turbine in response to movement of the elevator. Alternatively, the turbine may be of the self-starting type.

The turbine comprises blades having a variable pitch. Alternatively, the turbine blades may have a fixed pitch.

The power-take-off system may comprise a controller for controlling the starter and/or the pitch of the blades.

The power-take-off system may comprise: a first turbine configured to convert airflow substantially only in a first direction into usable energy; and a second turbine configured to convert airflow substantially only in a second direction, substantially opposite to the first direction, into usable energy.

The power-take-off system may comprise a check valve configured to permit fluid flow substantially only in one direction. For instance, each of the first and second turbines may be provided with an associated check valve for controlling fluid flow therethrough.

The elevator energy recovery system may further comprise: an elevator shaft; and an elevator within the elevator shaft; wherein power-take-off system is configured to convert airflow within the elevator shaft caused by movement of the elevator in the elevator shaft into usable energy.

The power-take-off system is located on an external vent of the elevator shaft.

The power-take-off system is located on a vent located between a leading surface and a following surface of the elevator.

According to a second aspect of the present invention, there is provided a method of recovering waste energy from movement of an elevator, including the steps of: providing the elevator energy recovery system according to the first aspect; moving the elevator within the elevator shaft; and converting airflow within the elevator shaft into usable energy with the power-take-off system.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 is schematic representation of a first elevator system.

Figure 2 is schematic representation of a second elevator system.

Figure 3 is schematic representation of a third elevator system.

The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspecf ’ in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term “at least one” may mean only one in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Figure 1 is schematic representation of a first elevator system, comprising an elevator shaft 1, an elevator 3, a bidirectional upper power-take-off system 5 and a bidirectional lower power-take-off system 7. The elevator 3 is movable up and down with the elevator shaft 1.

In (a) , as the elevator 3 moves upwards (indicated by arrow 9), air 11 is pushed through the upper power-take-off system 5, such that useful electrical energy may be generated by conventional means (not shown). Similarly, air 13 is pulled into the elevator shaft 1 behind the elevator 3 via lower power-take-off system 7, operating in a similar manner to the upper power-take-off system 5.

In (b), as the elevator 3 moves downwards (indicated by arrow 15), air 13 is pushed through the lower power-take-off system 7, such that useful electrical energy may be generated by conventional means (not shown). Similarly, air 11 is pulled into the elevator shaft 1 behind the elevator 3 via upper power-take-off system 5, operating in a similar manner to the lower power-take-off system 7.

In this way, each power-take-off system 5, 7 is in use while the elevator 3 is in motion within the elevator shaft 1.

Figure 2 is schematic representation of a second elevator system, comprising an elevator shaft 1, an elevator 3, first and second unidirectional upper power-take-off systems 17, 19 and first and second unidirectional lower power-take-off systems 21, 22. The elevator 3 is movable up and down with the elevator shaft 1.

In (a), as the elevator 3 moves upwards (indicated by arrow 9), air 11 is pushed through the first upper power-take-off system 17, such that useful electrical energy may be generated by conventional means (not shown). Similarly, air 13 is pulled into the elevator shaft 1 behind the elevator 3 via first lower power-take-off system 21, operating in a similar manner to the first upper power-take-off system 17.

In (b), as the elevator 3 moves downwards (indicated by arrow 15), air 13 is pushed through the second lower power-take-off system 23, such that useful electrical energy may be generated by conventional means (not shown). Similarly, air 11 is pulled into the elevator shaft 1 behind the elevator 3 via second upper power-take-off system 19, operating in a similar manner to the second lower power-take-off system 23.

In this way, relatively low cost unidirectional power-take-off systems 17, 19, 21, 23 may be used instead of relatively expensive bidirectional power-take-off systems 5, 7. The unidirectional power-take-off systems 17, 19, 21, 23 may incorporate valves, shutters or similar devices to prevent the air 11, 13 flowing therethrough in an undesired direction.

In alternative embodiments, a combination of bidirectional and unidirectional power-take-off systems may be used, for instance by incorporating a single upper bidirectional power-take-off system, and first and second lower unidirectional power-take-off systems. In yet further alternative embodiments, a plurality of power-take-off systems of similar configuration may be used, if appropriate to the elevator system in question.

Figure 3 is schematic representation of a third elevator system, comprising an elevator shaft 1, an elevator 3, a bidirectional upper power-take-off system 5 and a bidirectional lower power-take-off system 7. The upper power-take-off system 5 and the lower power-take-off system 7 are in fluid communication with one another via a conduit 25, located on the elevator 3. The elevator 3 is movable up and down with the elevator shaft 1.

As the elevator 3 moves upwards (indicated by arrow 9), air 11 is pushed through the upper power-take-off system 5 into the conduit 25, such that useful electrical energy may be generated by conventional means (not shown). Similarly, the air 11 is pulled from the conduit 25 into the elevator shaft 1 behind the elevator 3 via lower power-take-off system 7, operating in a similar manner to the upper power-take-off system 5.

In this way, the system may be conveniently retrofitted to an elevator, rather than to an entire elevator system including the shaft. In addition, such systems may be incorporated in elevator systems where venting of the elevator shaft is not convenient.

In an alternative embodiment, a single power-take-off system may be used instead of the upper and lower power-take-off system 5, 7. In this way, only one power-take-off system need be employed, particularly if that power-take-off system is bidirectional; however, equivalent systems using unidirectional power-take-off systems are also envisaged.

Claims

1. An elevator energy recovery system, comprising a power-take-off system configured to convert airflow within an elevator shaft into usable energy.

2. The elevator energy recovery system of claim 1, wherein the power-take-off system is configured to generate electricity.

3. The elevator energy recovery system of claim 1 or claim 2, wherein the power-take-off system comprises a turbine.

4. The elevator energy recovery system of any preceding claim, wherein the turbine comprises a bidirectional turbine.

5. The elevator energy recovery system of any preceding claim, wherein the turbine is configured to rotate about an axis substantially parallel to airflow incident thereon.

6. The elevator energy recovery system of any one of claims 1 to 4, wherein the turbine is configured to rotate about an axis substantially perpendicular to airflow incident thereon.

7. The elevator energy recovery system of any preceding claim, wherein the turbine comprises a starter, for initiating rotation of the turbine.

8. The elevator energy recovery system of any preceding claim, wherein the turbine comprises blades having a variable pitch.

9. The elevator energy recovery system of any preceding claim, wherein the power-take-off system comprises: a first turbine configured to convert airflow substantially only in a first direction into usable energy; and a second turbine configured to convert airflow substantially only in a second direction, substantially opposite to the first direction, into usable energy.

10. The elevator energy recovery system of any preceding claim, wherein the power-take-off system comprises a check valve configured to permit fluid flow substantially only in one direction.

11. The elevator energy recovery system of any preceding claim, further comprising: an elevator shaft; and an elevator within the elevator shaft; wherein power-take-off system is configured to convert airflow within the elevator shaft caused by movement of the elevator in the elevator shaft into usable energy.

12. The elevator energy recovery system of claim 11, wherein the power-take-off system is located on an external vent of the elevator shaft.

13. The elevator energy recovery system of claim 11 or claim 12, wherein the power-take-off system is located on a vent located between a leading surface and a following surface of the elevator.

14. A method of recovering waste energy from movement of an elevator, including the steps of: providing the elevator energy recovery system of claim 11, or claims 12 or 13 when dependent directly or indirectly on claim 11; moving the elevator within the elevator shaft; and converting airflow within the elevator shaft into usable energy with the power-take-off system.

15. An elevator energy recovery system substantially as hereinbefore described with reference to the accompanying drawings.