DEVICE FOR FLOW CONTROL

Technical field

The present invention relates to a device for flow control, and a system comprising such a flow control, for a fluid flow based building control system. Backgound of the invention Wireless systems, e.g. based on radio communication, have been more and more employed for control purposes. A problem arising with such systems is power supply. Either there has to be a power supply wire to each wireless device, which of course is detrimental for the advantages that a wireless system is to provide, or the devices are powered by batteries that have to be periodically replaced or charged. There has been presented solutions for self-powering of wireless control components, such as in US 2006/0063522 A1. US 2006/0063522 A1 discloses wireless radio solutions for directing operation of equipment and locating assets and personnel. The radio is powered by a dedicated energy generator, wherein the dedicated generator is suggested to generate electrical energy from vibrations, from a flow of fluid, from temperature gradients, from movement of mobile or portable items, from human movement by magnets or magnetic components, or from light energy by solar cells. However, there still remain a problem by putting the suggestions of US 2006/0063522 A1 into a practically feasible solution.

Summary of the invention

In view of the above, an objective of the invention is to solve or at least reduce the problems discussed above. In particular, an objective is to provide a flow control component which is suitable for producing an amount of electrical power, which over time is sufficient for operating the component to efficiently provide flow control, optionally including wireless communication, typically for a radiator device for heating/cooling a room or space in a building. It is further an objective to provide a system taking advantage of such a device, which will be a system which is easy to install, maintain, and supervise.

The present invention is based on the understanding that a properly designed flow control device can at the same time be suitable for controlling a fluid flow as being able to generate electric power. Further understandings for the provision of the embodiments of the present invention is that the ability to

generate electric power from the fluid flow by electric means can be inversed to provide an increase of fluid flow by providing electric power to electric means of the flow control device. Thus, conservation of electric power by some kind of electric accumulator is preferably provided to accumulate electric power during generation operation and to provide electric power during inverse operation, or to other functions consuming electric power, such as processing means, sensors, communication means, etc.

According to a first aspect of the present invention, there is provided a device for flow control in a HVAC fluid flow system, comprising means for extracting electric power from a fluid flow. The special features of the device is an inlet for a fluid and an outlet for the fluid such that the fluid form the fluid flow from the inlet to the outlet, the means for extracting electric power is arranged in the fluid flow between the inlet and the outlet, and flow controlling means are arranged in the fluid flow between the inlet and the outlet for controlling the fluid flow.

A particular advantage of such a device is that it at the same time is suitable for controlling a fluid flow and is able to generate electric power.

The flow controlling means may comprise the means for extracting the electric power, wherein the flow controlling means is operated by using the extracted electric power. A particular advantage of this feature is that a combined function of the flow controlling means is provided, which in practice provides for a product which can be both efficient to use and produce, and thus providing cost-savings.

The fluid flow may be enabled to be reduced by increasing extraction of electric power. An advantage of this is that more electric power can be extracted when flow is to be reduces, which is the most common case for a flow control device. Moreover, even if there is no particular need for the extracted electric power, this feature provides for easy control of the flow control device, since it is simple and well known art to provide an electrical dummy load, which may be electronically controlled, for extracting more electrical power.

The fluid flow may be reduced by mechanically affecting the flow controlling means. This may be performed by an electrically controllable actuator, brake or lock. The means for extracting electric power may comprise an electrical machine arranged to generate the electric power. The electric machine may also be arranged to be driven by electric power such that the fluid flow is

increased. A multitude of types of electrical machines are known per se, and most of them are suitable for use in this context. This provides for a feasible solution, which can be made cost-efficient and/or with a wanted design.

The means for extracting electric power may comprise rotating means arranged to be brought into rotation by the fluid flow. Thus, the rotation may be used for the extraction of electric power, e.g. by driving an electric machine such as a generator. The rotating means may be any of the group comprising an impeller, a blade wheel, a screw, a turbine, and a propeller. This provides for a feasible solution, which can be made cost-efficient and/or with a wanted design.

The rotating means may be enabled to be put into a state where the fluid flow is caused to substantially cease. This provides for a solution where a 'sleep mode' of the flow control and the fluid flow is provided, which can be feasible for e.g. reducing maintenance costs, safety purposes, etc. Further, this prevents unwanted self-heating or -cooling of a device for HVAC operation, e.g. a radiator device.

The device may further comprise an accumulator for storing the extracted electric power. The accumulator may be any of the group comprising a capacitor, a rechargable battery, and a lead accumulator. An advantage of having an accumulator is that electric power can be conserved when there is a high flow or pressure present in the fluid flow system, and this electric power can then be used when functions which require more electrical power than is available at a later instant. This can for example be that the flow controlling means may comprise an electrically actuated valve, and electrical power for actuating the valve is provided by the accumulator.

The device may further comprise a control unit arranged to provide a control signal, by which the flow controlling means is controlled. The control unit may comprise a communication means for communication with a building control system, e.g. the communication means may comprise a receiver for receiving control information, and/or the communication means may comprise a transmitter for transmitting data to a building control system. The transmitter of the communication means may be adapted to transmit data to other peer devices. This provides for a more flexible communication network in the system than is provided by strictly hierarchical communication. Thus an ad hoc network may be provided. The communication means may work as a repeater. The data may comprise any data item from the group of data items comprising status data and sensor data. The data may also be control

information to other similar devices, such as the device working as a repeater or as a central control unit. The data may comprise status data comprising any from the group comprising valve opening degree, position, and statistics. The data may comprise accumulator status, and charging status, surveillance data, and security data. The data may comprise life satety data comprising any of the group comprising emergency medical alarm, gas sensor data, and leakage guard. The data may comprise asset management data, identification data, and sensor data. The sensor data may comprise any of the group temperature, pressure, flow, accumulator voltage, and charging rate. Any combination of the above examples of data may be applicable, depending on the set-up of the system.

In accordance with the "wireless" power supply, the communication means may be arranged for wireless communication, which further facilitates installation, maintenance and supervision, and also higher level coordination and control.

According to a second aspect of the present invention, there is provided a system for HVAC comprising a building contol unit, at least one device for HVAC operation, and at least one device for flow control according to the first aspect of the present invention. Further advantages, than those demonstrated for the first aspect of the present invention, are improved comfort control and indoor environment, as well as energy savings.

The system according to the second aspect of the present invention, in the case when the optional communication means are present, at least one of the at least one device for flow control may be arranged to control fluid flow in at least one of the at least one device for HVAC operation based on information received from the building control unit by the communication means. The information may comprise a control signal for control of fluid flow. The information may also comprise a command, a load instruction, an exercise instruction, an instruction to acquire data, an instruction to provide status or sensor data, etc.

The system according to the second aspect of the present invention, in the case when the optional transmitter is present in any of the at least one device for flow control according to the first aspect of the present invention, at least one of the at least one device for flow control may be arranged to transmit data to the building control unit by the transmitter. The data to be transmitted may comprise any of the group comprising status data comprising

any from the group comprising valve opening degree, position, and statistics, accumulator status, and charging status, surveillance data, security data, life satety data comprising any of the group comprising emergency medical alarm, gas sensor data, and leakage guard, asset management data, identification data and sensor data comprising any of the group temperature, pressure, flow, accumulator voltage, and charging rate.

The system may further comprise conduits for providing the fluid flow to the at least one device for HVAC operation. The conduits may be arranged in a branch structure, and at least one branch in the branch structure may comprise flow enhancing means. The flow enhancing means may be controlled by the building control unit. The flow enhancing means may be any of the group comprising a pump, a fan, a compressor, and a blower.

The system according to the second aspect of the present invention when the optional communication means is present in any of the at least one device for flow control according to the first aspect of the present invention, the building control unit may comprise a transmitter for sending information to the at least one of the at least one device for flow control.

The system according to the second aspect of the present invention when the optional transmitter is present in any of the at least one device for flow control according to the first aspect of the present invention, the building control unit may comprise a receiver arranged to receive the data.

The device for HVAC operation may be any of the group comprising a heating or cooling radiator, a chilled ceiling beam, an air exhaust, and an air inlet, a heating or cooling coil, and a heat exchanger. Considering the improved flexibility of a system comprising devices for flow control according to the demonstrated invention, It will be appreciated that the flow control device or any associated device in the vicinity of it may perform other functions as well that is not directly within the HVAC field, such as functions for security, surveillance, communication, life safety such as medical emergency alarm or gas sensor, leakage guard, asset management, etc., if there is a demand for them and the extracted electrical power is sufficient. This provides for improved freedom in designing, and re-designing, the systems, improved comfort, and energy savings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc]" are to be interpreted openly as referring to at least one

instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Other objectives, features and advantages of the present invention will appear from the following detailed disclosure, from the attached dependent claims as well as from the drawings. Brief description of the drawings

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

Fig. 1 shows a fluid flow control set-up based on provision of electrical power by a power line; Fig. 2 shows a fluid flow control set-up based on provision of electrical power from an accumulator being charged by a generator, which also can be driven as a pump with power from the accumulator;

Fig. 3 shows an alternative set-up to the fluid flow control set-up in Fig. 2; Fig. 4 shows a system for HVAC;

Fig. 5 shows a flow controlling means in section according to an embodiment of the present invention; and

Fig. 6 shows a device according to an embodiment of the present invention. Detailed description of preferred embodiments

A properly designed flow control device can at the same time be suitable for controlling a fluid flow as being able to generate electric power. Further embodiments of the present invention, e.g. accumulation of electric power during generation operation, abilities to inverse generation of electric power from the fluid flow by electric means to provide an increase of fluid flow by providing electric power to electric means of the electric means, and provision of electric power to other functions consuming electric power, such as processing means, sensors, communication means, etc. will be discussed in this detailed description. For the understanding of the invention, Fig. 1 shows a fluid flow control set-up 100 based on provision of electrical power by a power line 102 providing power to an actuator 104. The actuator 104 is normally in mechanical connection 106 with a valve 108 for putting the valve

108 in a desired state. A control unit 110, which can be in communication with a building control system (not shown), provides a control signal 112 to the actuator 104, and in response to the control signal 112, the actuator 104 puts the valve 108 in the desired state. The valve 108 affects a fluid flow 114 flowing in a conduit to an inlet 116 of the valve 108, and from an outlet 118 from the valve 108. The fluid flow can be a liquid or a gas. In building heat and ventilation systems, water is commonly used for transporting fluids for heating or cooling, but other liquids can be used as well. For ventilation purposes, the fluid flow is normally air. However, other gases can apply for certain purposes. The set-up 100 shown in Fig. 1 applies to all of these fluids. The set-up can comprise more elements (not shown) such as sensors, further pipes and valves, heating or cooling radiators, chilled ceiling beams, air exhausts, air inlets, heating or cooling coils, and heat exchangers.

Fig. 2 shows another set-up 200 comprising similar elements as shown in Fig. 1 , such as an actuator 204 in mechanical connection 206 with a valve 208 for putting the valve 208 in a desired state. A control unit 210, which can be in wireless communication with a building control system (not shown) by means of a wireless communication unit (not shown) with an aerial 211 , provides a control signal 212 to the actuator 204, and in response to the control signal 212, the actuator 204 puts the valve 208 in the desired state. The valve 208 affects a fluid flow 214 flowing in a conduit to an inlet 216 of the valve 208, and from an outlet 218 from the valve 208. An element 220 is arranged to let the fluid flow 214 flow through it. The element 220 can comprise a generator, or comprise a combined generator and pump. By the generator, electric power is extracted from the fluid flow. The electric power can be used directly by elements consuming electric power, such as the actuator 204 and the control unit 210, or, as depicted in Fig. 2, be conserved in an accumulator 222, which in turn provides electric power to elements consuming electric power, such as the actuator 204 and the control unit 210. The accumulator can for example be a capacitor, a rechargable battery, or a lead accumulator, depending on the needed storage capacity. Conserved electric power can also be provided to the element 220 when comprising a combined generator and pump, wherein the pump function of the element 220 is used to increase the fluid flow instead of using the generator function of the element to extract electric power.

Figs 1 and 2 have briefly described functional elements of exemplary set-ups related to the area within which the invention is applicable. Before

looking at an exemplary embodiment of the present invention shown in Fig. 3, a reasoning about power will be provided. If a hydraulic system is considered, the available power depends on the density of the fluid, the flow, and the second power of the velocity of the fluid. Since we consider a system with an essentially constant geometry, the flow and the speed of the fluid strongly depend on each other at each location of the flow path, and the density of the fluid can be considered to be constant. When power is extracted from the flow, i.e. electric power generated in the present invention, the flow and the velocity will decrease since the remaining power will be lower. A similar reasoning is applicable for gas flow. Thus, by extracting electric power in a contolled manner, the fluid flow can be controlled. Thus, the essence of the invention is that flow control can be made by extracting power and controlling the fluid flow as a combined operation. This is provided by a flow control device comprising means for extracting electric power from the fluid flow and flow controlling means. In one embodiment of the present invention, which will be described below, the flow controlling means comprises the means for extracting electric power from the fluid flow.

With reference to the discussion above regarding power, and the setup 200 shown in Fig. 2, the control unit can be arranged to control both the element 220 and the valve 208 by the actuator 204 by a suitable control model to achieve proper control of the fluid flow. The control model can preferably be implemented as a computer program to be executed in the control unit.

Fig. 3 shows an alternative set-up to the fluid flow control set-up in Fig. 2. A control unit 310, which can be in wireless communication with a building control system (not shown) by means of a wireless communication unit (not shown) with an aerial 311 , provides control of an element 320. The element 320 can comprise a generator, or comprise a combined generator and pump. By the generator, electric power is extracted from a fluid flow 314, and in accordance with the power discussion above, the fluid flow 314 is controlled by the amount of extracted power. Thus, the connection 312 between the control unit can only be a power cable, wherein as much power is extracted, by control of the control unit 310, as is required for getting the desired fluid flow 314. The connection 312 can comprise further functions, such as supervision of the function of the element 320, e.g. for feedback to the control unit 310. The element 320 affects the fluid flow 314 flowing in a conduit to an inlet 316 of the element 320, and from an outlet 318 from the element 320.

The electric power can be used directly by elements consuming electric power, such as the control unit 310, or be conserved in an accumulator 322, which in turn provides electric power to elements consuming electric power, such as the control unit 310. Conserved electric power can also be provided to the element 320 when comprising a combined generator and pump, wherein the pump function of the element 320 is used to increase the fluid flow 314 instead of using the generator function of the element 320 to extract electric power and decrease the fluid flow 314. The control unit 310 can be arranged to control the element 320 by a suitable control model to achieve proper control of the fluid flow 314. The control model can preferably be implemented as a computer program to be executed in the control unit 310.

Returning to Fig. 1 and with reference to the discussions above regarding fluid flow power and electric power, and control models for controlling the fluid flow by extracting electric power, although the set-up 100 is provided with a power line 102, the approach for controlling the fluid flow 114 demonstrated with reference to Figs 2 and 3 can be applied to the set-up 100 shown in Fig. 1. Thus, to the actuator 104 and valve 108, an element similar to element 220 discussed with reference to Fig. 2 is added, and the control unit 110 provides control by a control model for combined control by the valve 108 and the element, or the actuator 104 and the valve 108 are substituted by an element similar to element 320 discussed with reference to Fig. 3, which is controlled in a similar way as discussed with reference to Fig. 3. Here it can be seen that generation of electric power for consumption is not essential. The extraction of electric power can be used for generation and/or control of the fluid flow.

The elements 220 and 320 preferably comprises an electric machine, such as a dynamo-electric machine, an asynchronous machine, or a synchronous machine. The electric machine provides for ability to be used both as a generator and as a means for enhancing the fluid flow. Here, the electric machine can be in mechanical connection with a rotating means which is brought into rotation by the fluid flow, such as an impeller, a blade wheel, a screw, a turbine, or a propeller. This provides for a solution where decrease of the fluid flow and generation of electric power in one operation mode, and increase of fluid flow in another operation mode are provided. By proper control of the element, it can be put in a state where the fluid flow is caused to substantially cease.

Fig. 4 shows an exemplary system 400 for HVAC, comprising a building control unit 402, a plurality of devices for HVAC operation 404 and a plurality of devices for flow control 406. The devices for flow control 406 can be of any of the types describe above with reference to Figs 1 to 3. The devices for HVAC operation can be heating or cooling radiators, chilled ceiling beams, air exhausts, air inlets, heating or cooling coils, heat exchangers, etc. In Fig. 4, bold lines between elements denote fluid flow paths, such as pipes, conduits, ducts, etc. Other solid lines denote electric connections. The conduits etc. can be arranged in a branch structure, where Fig. 4 illustrates a system divided into two fluid flow circuits, e.g. one for a first type of fluid, and a second for a second type of fluid. One of the fluid flow circuits further comprises two branchs. The system comprises at least one flow enhancing means for providing a fluid flow in the conduits etc. The flow enhancing means can be a pump, a fan, a compessor, a blower, etc., depending on the type of fluid flow that is demanded. The flow enhancing means can be common for the entire system, and/or one or more of the branches can have their own flow enhancing means. In Fig. 4, each branch has a flow enhancing means 408, which is controlled by the building control unit 402. At least one of the devices for flow control 406 are arranged to control fluid flow in their corresponding device for HVAC operation based on information received from the building control unit 402. The information can be transmitted on wire or wirelessly to the flow control devices 406, which receive the information by a receiver and perform control operations according to the received information. The information can also comprise a command, a load instruction, an exercise instruction, an instruction to acquire data, an instruction to provide status or sensor data, etc. This provides for more advanced operations to be performed by the device. For example, an exercise instruction is received, and the device starts a predetermined program of controlling the flow controlling means, e.g. testing minimum and maximum control values, step response, etc.

At least one or some of the flow control devices 406 can also have a transmitter for sending information to the building control unit, or any of the other flow control devices 406 or other device (not shown). Thus, the receiving entities need to have a receiver for receiving the information. The transmitted information can comprise status data and/or sensor data. Thus, the control units in the system can have one or more associated sensors measuring relevant physical amounts. This provides for feed-back from the

operating system to the building control unit, e.g. for minimising flow in each branch, and minimising temperature of the fluid in the return line. A non negligible amount of energy can be saved this way. With reference to the above example where an exercise instruction is received, a status message can be transmitted to the building control unit with results from the exercise, which in turn can be stored and used for improving control of the device. The transmitted data can comprise status data comprising e.g. valve opening degree, position, and statistics. The data can also comprise accumulator status, charging status, surveillance data, security data, life satety data such as emergency medical alarm, gas sensor data and leakage guard. The data can also be asset management data, identification data, and sensor data. The sensor data can be data on temperature, pressure, flow, accumulator voltage, charging rate, etc.

Fig. 5 shows mechanical parts of a flow controlling means 500 in section according to an embodiment of the present invention. The flow controlling means 500 comprises an inlet 502 and an outlet 504, wherein the fluid flow is to be flowing from the inlet 502 to the outlet 504. The flow controlling means 500 can comprise a rotating means 506 arranged to rotate around its shaft 508. The shaft can then be mechanically connected to an electric machine (not shown). Upon fluid flow, the rotating means 506 is brought into rotation, wherein electric power can be extracted as has been discussed above, and thus the fluid flow be controlled. Similar, by bringing the rotating means 506 into rotation, e.g. by driving the electric machine with accumulated electric power, the fluid flow can be increased, or even reversed for e.g. evacuation, cleaning, exercising, etc. The rotating means can also be put in a state where the fluid flow is caused to substantially cease. For example, if the rotating means is locked in the position shown in Fig. 5 by the electric machine, substantially no fluid is able to pass from the inlet 502 to the outlet 504. Fig. 6 shows a device 600 according to an embodiment of the present invention. Fig. 6a is a view in section along line A-A, and Fig. 6b is a view in section along line B-B. The device comprises an inlet 602 and an outlet 604. However, it is evident that the fluid flow can be opposite. In the fluid flow path, there is provided a rotating means 606 arranged to rotate with its shaft 608, which is mechanically connected to a winding, magnet or electrostatic means 610 of an electric machine 612. In the electric machine 612, there is also

provided a stator winding 614, which is connected by wires 616 to provide extracted electric power or to be powered for increasing fluid flow.

During seasons where very little or no flow is present in the ducts to the HVAC devices in the system, there may be a lack of energy in the flow control devices, such as one or more accumulators become discharged. This is feasibly solved on a system level. This can be done either by periodically providing a flow with, preferably room temperatured, fluid in all or selected branches of the system to let the flow control devices re-charge their accumulators. Another possibility is that this is initiated by a flow control device communicating to the building control unit that a certain low level of charge has been reached in the accumulator. The building control system then provides for a fluid flow in all or selected branches of the system to let the flow control devices re-charge their accumulators. A control message may be sent to all flow control devices in question to maximise charging during these operations.

The invention has been discussed on flow control device level, HVAC device level and system level in question of building control device. However, the aggregation of particulars of the present invention provides for improved control of HVAC devices, as well of control of flow in each branch. This in turn provides for ability to optimise energy consumption for each HVAC device, as well of optimising energy consumption for providing the fluid flow in the system. All this together provides for substantial energy savings in a building or system of buildings, and at the same time improved comfort, as will be readily understood by the artisan acquainting herself with the contents of the above disclosure.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.