Window-fitted ventilation unit and building ventilation system

Field of the invention

The invention more generally relates to the field of building technology, and more particularly to ventilation windows and building ventilation systems .

Technical background

Ventilation windows are known from European patent application of IFN-Holding AG published under publication number

EP 2 594 725 A2 , from German patent application of Hautau GmbH published under publication number DE 10 2012 104198 Al .

Also the present applicant has a patent application on a ventilation window. The ventilation window has been described in Finnish patent application 20135214, at the time of writing still unpublished.

Objective of the invention

It is an objective of the invention to increase the versatility of ventilation windows and to improve controllability of a building ventilation system.

This objective can be solved with the window-fitted ventilation unit according to claim 1 and a building ventilation system comprising a plurality of window-fitted ventilation units according to claim 22.

The dependent claims describe various advantages of the window- fitted ventilation unit and of the building ventilation system.

The term "building" is in the foregoing and below intented to mean a building, in particular a house or an office building, or a part thereof, in particular an appartment or flat, or even a room. The term apartment is below intented to mean a set of rooms for living in, such as on one floor of a large building, or a flat that usually includes a kitchen and a bathroom. The term apartment should however be understood also to mean office premises . Advantages of the invention

The window-fitted ventilation unit comprises a) an electronic circuit with a microcontroller, b) at least one fan for

transferring fresh air from outer side to inner side as incoming air through at least one air inlet channel passing through a cross-counter-flow heat exchanger, c) at least one fan for transferring outgoing air from inner side to outer side as waste air through at least one air outlet channel passing through the cross-counter-flow heat exchanger, d) at least one driver circuit for controlling said at least two fans, the at least one driver circuit being controllable by the microcontroller, e) a number of sensors connected to the microcontroller, and f) at least one communication interface connecting the microcontroller to a building ventilation system.

The microcontroller comprises a register with status information of devices connected to the building ventilation system, and is configured to listen to the communication interface for

receiving status information from the building ventilation system via the communication interface, and to update the register upon receiving status information that is more actual than status information stored in the register.

In this manner, the versatility of ventilation windows can be increased since the window-fitted ventilation unit will have available status information from the building ventilation system. Preferably, this status information includes information of the devices in the building ventilation system. In this manner, the window-fitted ventilation unit can be configured to change its operational status based on status information of other devices in the building ventilation system, or in other words, made responsive to status information of other devices in the building ventilation system, in particular of other window- fitted ventilation units and/or outlet valves controlled by the building ventilation system.

If the microcontroller is configured to broadcast updated contents of the register to the building ventilation system via the communication interface, the building ventilation system can be implemented technically in a relatively simple manner. The benefit of broadcasting updated contents is that in this manner, every device connected to the building ventilation system can have the updated status information available.

The great advantage that can be achieved with the use of broadcasting is that in this manner, the implementing of the building ventilation system as a distributed system can be carried out with technically relatively simple components. The devices in the building ventilation system do not necessarily need to poll or query the building ventilation system. If a status of one window-fitted ventilation unit is changed, the other devices in the building ventilation system will have the so updated status information available with a relatively small delay only. In this manner, controlling the devices of the building ventilation system, and in particular the window-fitted ventilation units, in a group or subgroup can be made possible with technically rather simple components. Furthermore, it may become possible to implement the building ventilation system with a peer-controlled group i.e. without using a host computer.

If the microcontroller is configured to store the status information in a matrix, the status information can be handled effectively in the microcontroller.

If the microcontroller is configured to store status information of each of the devices connected to the building ventilation system in the matrix, the handling of the status information can be made from algorithm point of view with relatively simple algorithms in the microcontroller. This enables fast performance operation on the microcontroller.

If the status information comprises at least one operating parameter of each of the devices connected to the building ventilation system, the window-fitted ventilation unit can be understood to have replicated the status of the building ventilation system available at all times when the window-fitted ventilation unit is in operation. This may be used to reduce the need for communication between the devices in the building ventilation system since in this manner the window-fitted ventilation units do not need to query the status information from the other devices in the building ventilation system.

If the window-fitted ventilation unit is configured to increase operating speed of at least one of the fans in response to receiving status information from the building ventilation system via the communication inteface, the window-fitted ventilation unit can be made controllable by the building ventilation system in a relatively simple manner. This enables the controlling of the window-fitted ventilation device as a member of a group or a subgroup of the building ventilation system, to increase air intake and/or air outlet.

If the window-fitted ventilation unit is configured to increase operating speed of the at least one fan for transferring fresh air from outer side to inner side and also of the at least one fan for transferring outgoing air from inner side to outer side as waste air in response to receiving status information via the communication inteface, the window-fitted ventilation unit can be made controllable by the building ventilation system in a relatively simple manner. This enables the controlling of the window-fitted ventilation device as a member of a group or a subgroup of the building ventilation system, to increase ventilation .

If the window-fitted ventilation unit is configured to increase operating speed of the fans in response to receiving status information via the communication inteface, if the status information indicates that at least one of the devices connected to the building ventilation system has an increased ventilation status activated and/or that away-function has been deactivated, this enables a particularly simple group or subgroup control of the window-fitted ventilation unit by the building ventilation system for increasing ventilation.

The window-fitted ventilation unit may be configured to reduce operating speed of at least one of the fans in response to receiving status information from the building ventilation system via the communication inteface. This enables the

controlling of the window-fitted ventilation device as a member of a group or a subgroup of the building ventilation system, to reduce air intake and/or air outlet.

If the window-fitted ventilation unit is configured to reduce operating speed of the at least one fan for transferring fresh air from outer side to inner side and also of the at least one fan for transferring outgoing air from inner side to outer side as waste air in response to receiving status information from the building ventilation system via the communication inteface, the window-fitted ventilation unit can be made controllable by the building ventilation system in a relatively simple manner. This enables the controlling of the window-fitted ventilation device as a member of a group or a subgroup of the building ventilation system, to reduce ventilation.

If the window-fitted ventilation unit is configured to reduce operating speed of the fans in response to receiving status information from the building ventilation system via the communication interface, if the status information indicates that at least one of the devices connected to the building ventilation system has an increased ventilation status

deactivated and/or that away-function has been activated, this enables a particularly simple group or subgroup control of the window-fitted ventilation unit by the building ventilation system for reducing ventilation.

Preferably, the the window-fitted ventilation unit will be installed or has been installed in a vertical frame of a window. This improves the functioning of the cross-counter-flow heat exchanger and facilitates the removal of condensate from the window-fitted ventilation unit.

In this case, the at least one inlet and at least one respective outlet of the air inlet channel and at least one inlet and at least one respective outlet of the air outlet channel are advantageously all located in the vertical frame. This

facilitates the manufacturing of the ventilation window in which the window-fitted ventilation unit is going to be installed, since it will be only the vertical frame and not the horizontal frames or the sashes, for instance, that need to modified for accommodating the window-fitted ventilation unit.

Even more advantageously, the air inlet channel and the air outlet channel may be conducted all the way between the inlets and the respective outlets within the window-fitted ventilation unit. In this manner, the window-fitted ventilation unit can be made a separate unit in the ventilation window. This arrangement facilitates in avoiding or mitigating problems that may result from condensate, in particular if the window frame is made of or comprises wood, or metal (such as aluminium) profile or plastic profile .

Alternatively or in addition to this, if the cross-counter-flow heat exchanger has an elongated shape and the air inlet channel comprises at least two elongated segments, namely a transfer channel and a fresh air channel of the cross-counter-flow heat exchanger, the heat transfer ratio in the heat exchanger may be improved. This supports in increasing energy efficiency of the window-fitted ventilation unit and potentially also of the building ventilation system in which the window-fitted

ventilation unit is deployed. Furthermore, the transfer channel may be used to pre-heat (even minimally) the air before letting it enter the cross-counter-flow heat exchanger, if the transfer channel is located in the flow direction before the fresh air channel of the cross-counter-flow heat exchanger.

If the cross-counter-flow heat exchanger has an elongated shape and the air outlet channel comprises at least two elongated segments, namely a suction channel and an outlet air channel of the cross-counter-flow heat exchanger, it will be possible to increase the length of the air inlet channel. This is

particularly advantageous if the suction channel is located before the outlet air channel of the cross-counter-flow heat exchanger, since in this manner also the path for noise that may generated by the fans operating close to the cross-counter-flow heat exchanger may be made longer.

The suction channel and/or the transfer channel may comprise acoustic attenuation arrangement, in particular attenuation material and a guide in the channel. Alternatively or in addition, the fan(s) may be installed in one or more attenuation chassis for imporoved vibration damping. This is particularly useful if the attenuation chassis is made of or comprises thermoplastics or elastomer.

If the transfer channel runs from top to down and the suction channel runs from down to top, the flow direction in the cross- counter-flow heat exchanger can be optimized. This means that, on one hand, natural convection can be used. On the other hand, condensate can be made move always downwards with air flow, in other words, so being removed from the window-fitted ventilation unit with assistance of gravity.

The communication interface to the building ventilation system may be realized by using a radio interface. This helps to avoid cabling between different units. Alternatively or in addition to this, the communication interface to the building ventilation system may be realized by using a CAN -bus. In this manner, the building ventilation system can be implemented without a host computer .

The microcontroller may be configured to determine whether status information received is more actual than status

information stored in the register by comparing a time stamp or a counter value in the received status information with a respective time stamp or a counter value in the status

information stored in the register.

The building ventilation system comprises a group of window- fitted ventilation units according to any one of the preceding claims . The building ventilation system may also comprise controlled outlet valves, power and data terminal and also a data server that preferably may be integrated in power and data terminal. The controllability of the building ventilation system may be improved, since it will be possible to control each of the window-fitted ventilation units separately within the building ventilation system.

In the building ventilation system, a subgroup of the window- fitted ventilation units may be configured to, in response to receiving status information that indicates that at least one window-fitted ventilation unit of the group, not belonging to the subgroup, has changed an operating parameter of at least one of its fans in such a manner that the volume ratio between incoming air and outgoing air through said window-fitted ventilation unit has increased or decreased, to change operation of fans of at least one window-fitted ventilation unit of the subgroup so that the volume ratio between incoming air and outgoing air is changed into the opposite direction i.e.

decreased or increased, respectively. In this manner, a change in the building or apartment ventilation one or mode window- fitted ventilation units can be compensated for automatically.

If all or at least some window-fitted ventilation units of the group or of the subgroup are configured to assist de-icing a window-fitted ventilation unit in such a manner that:

- the at least one fan for transferring fresh air from outer side to inner side as incoming air through the at least one air inlet channel passing through the cross-counter-flow heat exchanger of the window-fitted ventilation unit to be de-iced is slowed down or brought to halt, while the at least one fan for transferring outgoing air from inner side to outer side as waste air through at least one air outlet channel passing through the cross-counter-flow heat exchanger is operated; and optionally also

- all other or at least some of the other window- fitted ventilation units of the group or of the subgroup are configured to change operation of fans of at least one window-fitted ventilation unit of the subgroup so that the volume ratio between incoming air and outgoing air is increased to compensate for the fan that is slowed down or brought to halt, de-icing (this term includes also defrosting) can be carried out in an effective manner without employing any separate heater in the air inlet channel. Advantageously, in the building ventilation system, at least some, preferably all window-fitted ventilation units in the group or subgroup group are configured to generate draught in the building or in part of the building, such as in an

apartment. In this manner, ventilation can be implemented in a particularly effective manner.

The building ventilation system may further comprise a data server for recording status information broadcasted in the building ventilation system as time series.

The data server may be configured to deliver status information recorded as time series to a control application, such as an applet, executable in a microprocessor, such as on a smart phone or portable computer, for diplaying operational state of ventilation units.

Instead of this or in addition, the data server or the control application may be configured to compute usage of a filter using the recorded time series and indicate that the filter needs replacement or maintenance if a threshold has been exceeded.

Advantageously, the threshold may be computed by summing over part of the time series and weighting with an operation mode indicator. In this manner, the filter replacement can be indicated based on real usage of the window-fitted ventilation unit .

The data server may be configured to receive commands from a control application, such as an applet, executable in a

microprocessor, such as on a smart phone or portable computer, for controlling ventilation units.

The application may be configured to control window-fitted ventilation units in different rooms of a building or of an apartment independently of each other or as groups.

List of drawings

In the following, the window-fitted ventilation unit is

described in more detail with reference to the exemplary embodiments shown in FIG 1 to 23 and 26 of the attached

drawings, of which: illustrates a perspective view of a first ventilation window with window-fitted ventilation unit, as viewed from inside a building; illustrates a perspective view of the ventilation window of FIG 1, as viewed from outside a building; illustrates the ventilation window of FIG 1, as viewed from inside a building, directly from the front; illustrates the ventilation window of FIG 1, as viewed from outside a building, directly from the front; illustrates the ventilation window of FIG 1, as viewed from inside a building, the outer sash and the inner sash opened to inside the building; is horizontal section VI-VI of the ventilation window illustrated in FIG 1; illustrates the window-fitted ventilation unit, as viewed from direction facing the channels leading to outside of a building; is horizontal section VIII-VIII of the ventilation unit of FIG 7; is vertical section IX-IX of the ventilation unit of

FIG 7; is vertical section X-X of the ventilation unit of FIG 7; is vertical section XI-XI as defined in FIG 9; is vertical section XII-XII as defined in FIG 9; is exploded view of parts contained in the ventilation unit of FIG 7; illustrates electrical parts of the ventilation unit; illustrates internal function of window-fitted ventilation unit at power-on; illustrates the operation of window-fitted ventilation unit after power-on; illustrates peripheral initialization subroutine in the window-fitted ventilation unit; describes a possible manner of handling interrupts in the microcontroller; a possible manner of handling interrupts in the microcontroller; contains a diagram illustrating certain device states of the window-fitted ventilation unit and possible transitions between the device states; is a circuit board of the ventilation unit of FIG 7, as viewed from the top; is the circuit board shown in FIG 17, as viewed from below; is a schematic circuit diagram of the circuit board of the ventilation unit; is a perspective view of a second ventilation window with window-fitted ventilation unit, as viewed from inside a building; illustrates a perspective view of the ventilation window of FIG 20, as viewed from outside a building; illustrates a first embodiment of a building

ventilation system; illustrates a second embodiment of a building

ventilation system; 25 illustrate a current state of the art building ventilation solution; and illustrates a possible use scenario of the building ventilation system according to the present invention Same reference numerals refer to same structural elements in all FIG.

Detailed description

FIG 7 illustrates window-fitted ventilation unit 50, as viewed from the direction facing the channels (outlet 54 for waste air 23 and inlet 51 for fresh air 20) leading to outside U of a building .

Window-fitted ventilation unit 50 is intended to be installed into vertical frame 2 of ventilation window 1, or,

alternatively, onto vertical frame 2. Even though the examples show the window-fitted ventilation unit 50 fitted in the left vertical frame when viewed from inner side S, the window-fitted ventilation unit 50 may be fitted to the right vertical frame res...

Two examples of a ventilation window 1 into which (or onto the frame of which) window-fitted ventilation unit 50 is installed or is inteded to be installed are disclosed in this document, namely :

- FIG 1 to 6 disclose a first ventilation window 1 with ventilation unit 50 installed. This ventilation window 1 has at least two sashes, namely inner sash 3 and outer sash 4, between which there is intermediate space 10.

- FIG 20 and 21 disclose a second ventilation window 1 with ventilation unit 50 installed. This ventilation window 1 has no intermediate space but the glass pane (or glass element) 5 is fixed to frame 2 or to sash which there may be optionally.

Both ventilation windows 1 may, but do not need to be openable. Regarding openability of ventilation window 1 of FIG 20 and 21 this in practice would require the presence of at least one sash to which glass pane (or glass element) 5 is fixed.

For the explanation of possible details of both ventilation windows, see the reference numeral list. The channel structure of ventilation unit 50 that is preferably used will be explained in more detail with reference to FIG 8 to

12. Structural details of ventilation unit 50 are shown in FIG

13. Electrical system 80 of ventilation unit 50 is shown in FIG 14 and schematically in FIG 19. Circuit board 82 is illustrated in FIG 17 and 18.

Certain operating methods of window-fitted ventilation unit 50 will be explained in context of FIG 15A to 15E and 16.

FIG 1 illustrates a perspective view of ventilation window 1 with window-fitted ventilation unit 50 installed, as viewed from inside a building. FIG 2 illustrates a perspective view of the ventilation window 1 of FIG 1, as viewed from outside U of the building .

Window-fitted ventilation unit 50 is most preferably installed in recess 14 made in vertical part of frame 2. Ventilation unit 50 may reach intermediate space 10, i.e. the space between inner sash 3 and outer sash 4. Sashes 3, 4 define light opening 7.

FIG 3 illustrates the ventilation window 1 of FIG 1, as viewed from inside S of the building, directly from the front. FIG 4 illustrates the ventilation window 1 of FIG 1, as viewed from outside U of the building, directly from the front.

FIG 5 illustrates the ventilation window of FIG 1, as viewed from inside S of the building, the outer sash 4 and the inner sash 3 opened to inside the building (towards inner side S) .

FIG 6 is horizontal section VI-VI of the ventilation window 1 illustrated in FIG 1.

FIG 7, 13, 14, 17, 18 and 19 illustrate window-fitted

ventilation unit 50 that comprises electrical system 80 having electronic circuit 90 with circuit board 82 having a

microcontroller 91.

Window-fitted ventilation unit 50 has at least one fan 64 for transferring fresh air 20 from outer side U to inner side S as incoming air 21 through at least one air inlet channel (such as, in particular, transfer channel 65 and fresh air channel 62A of the cross-counter-flow heat exchanger 62 ) , the air inlet channel passing through cross-counter-flow heat exchanger 62.

Furthermore, the window-fitted ventilation unit 50 has at least one fan 63 for transferring outgoing air 22 from inner side S to outer side U as waste air 23 through at least one air outlet channel (such as, in particular, suction channel 66 and outlet air channel 62B of the cross-counter-flow heat exchanger 62), the air outlet channel passing through cross-counter-flow heat exchanger 62.

Window-fitted ventilation unit 50 comprises also at least one driver circuit 92 for controlling the at least two fans 63, 64. The at least one driver circuit 92 is preferably controllable by microcontroller 91.

Window-fitted ventilation unit 50 also comprises a number of sensors (such as, carbon-dioxide sensor C0 ₂ , relative humidity sensor RH, temperature sensors Tl, T2, T3, T4) connected to the microcontroller 91.

Window-fitted ventilation unit 50 also comprises at least one communication interface (CAN bus 93, wireless network 93', radio module 95, antenna 96, CAN adapter 94, LOW-level CAN bus line pin 102, HIGH-level CAN bus line pin 103) connecting the microcontroller 91 to building ventilation system 200.

Microcontroller 91 comprises a register with status information of devices (such as, window-fitted ventilation units 50, controlled outlet valves 303, power and data terminal 304, data server 305) connected to building ventilation system 200.

The microcontroller 91 is configured to listen to the

communication interface for receiving status information from building ventilation system 200 via the communication interface, and to update the register upon receiving status information that is more actual than status information stored in the register .

Preferably, microcontroller 91 may be configured to broadcast updated contents of the register to building ventilation system 200 via the communication interface. The microcontroller 91 may be configured to store the status information in a matrix. In particular, microcontroller 91 may be configured to store status information of each of the devices connected to building ventilation system 200 in the matrix.

The status information may comprise at least one operating parameter of each of the devices connected to building

ventilation system 200.

Window-fitted ventilation unit 50 may be configured to increase operating speed of at least one of the fans 63, 64 in response to receiving status information from building ventilation system 200 via the communication inteface.

Alternatively or in addition, window-fitted ventilation unit 50 may be configured to increase operating speed of the at least one fan 64 for transferring fresh air 20 from outer side U to inner side S and also of the at least one fan 63 for

transferring outgoing air 22 from inner side S to outer side U as waste air 23 in response to receiving status information via the communication inteface.

Alternatively or in addition, window-fitted ventilation unit 50 may be configured to increase operating speed of the fans 63, 64 in response to receiving status information via the

communication inteface if the status information indicates that at least one of the devices connected to the building

ventilation system 200 has an increased ventilation status activated and/or that away-function has been deactivated.

Alternatively or in addition, the window-fitted ventilation unit 50 may be configured to reduce operating speed of at least one of the fans 63, 64 in response to receiving status information from building ventilation system 200 via the communication inteface .

Alternatively or in addition, the window-fitted ventilation unit 50 may be configured to reduce operating speed of the at least one fan 64 for transferring fresh air 20 from outer side U to inner side S and also of the at least one fan 63 for

transferring outgoing air 22 from inner side S to outer side U as waste air 23 in response to receiving status information from building ventilation system 200 via the communication inteface.

Alternatively or in addition, the window-fitted ventilation unit 50 may be configured to reduce operating speed of the fans 63, 64 in response to receiving status information from the building ventilation system 200 via the communication interface if the status information indicates that at least one of the devices connected to the building ventilation system has an increased ventilation status deactivated and/or that away-function has been activated.

As mentioned earlier, window-fitted ventilation unit 50 is preferably installed in a vertical frame 2 of a ventilation window 1. The at least one inlet 20 and at least one respective outlet 21 of the air inlet channel and at least one inlet 53 and at least one respective outlet 54 of the air outlet channel are preferably all located in the vertical frame 2.

The air inlet channel and the air outlet channel are preferably conducted all way between the inlets 51, 53 and the respective outlets 52, 54 within the window-fitted ventilation unit 50.

Preferably, the cross-counter-flow heat exchanger 62 may have an elongated shape and the air inlet channel may comprise at least two elongated segments, namely transfer channel 65 and fresh air channel 62A of the cross-counter-flow heat exchanger 62.

The cross-counter-flow heat exchanger 62 may have an elongated shape and the air outlet channel may comprise at least two elongated segments, namely a suction channel 66 and an outlet air channel 62A of the cross-counter-flow heat exchanger 62.

Preferably, the transfer channel 65 runs from top to down whereas the suction channel 66 runs from down to top.

The communication interface to the building ventilation system 200 may be realized with radio interface, such as, with

components for connecting the window-fitted ventilation unit 50 to wireless network 93' . Alternatively to this or in addition, the communication

interface 93 to the building ventilation system 200 can be realized with a wire-based network or optical network, such as, with components for connecting the window-fitted ventilation unit 50 to CAN bus 93.

Microcontroller 91 may be configured to determine whether status information received is more actual than status information stored in the register by comparing a time stamp or a counter value in the received status information with a respective time stamp or a respective counter value in the status information stored in the register.

At least in theory, window-fitted ventilation unit 50 could be implemented so that instead of the cross-counter-flow heat exchanger 62 another type of heat exchanger is used. For example, a cross-flow heat exchanger or a rotating heat

exchanger could be then used instead.

Here the air channel structures of the preferred embodiment are explained in more detail. FIG 8 is horizontal section VIII-VIII of the window-fitted ventilation unit 50 of FIG 7. FIG 9 is vertical section IX-IX of the ventilation unit 50. FIG 10 is vertical section X-X of the ventilation unit 50. FIG 11 is vertical section XI-XI and FIG 12 is vertical section XII-XII as defined in FIG 9.

FIG 13 shows in exploded view parts contained in the window- fitted ventilation unit 50. FIG 14 illustrates electrical parts of the ventilation unit 50, i.e. electrical system 80. FIG 17 shows circuit board 82 of the ventilation unit 50, as viewed from the top, and FIG 18 as viewed from below. FIG 19 is a schematic circuit diagram of circuit board 82 of the ventilation unit 50.

The state of devices in building ventilation system 200 is stored in a matrix. A communication protocol is used for updating the matrix. Each column in the matrix describes state of one device of the building ventilation system 200. The devices in the building ventilation system 200 can be window- fitted ventilation units 50, controlled outlet valves 303 (such as valves in toilet/bathroom/shower room KPH or in kitchen K) , user interface panel 311 (which may be one or more) , data server 305, and optionally a web interface, Internet interface or

Intranet interface .

Each row in the matrix may contain parameters for describing the state of the devices of building ventilation system 200. There may be a row present for each outlet fan 63 speed, inlet fan 64 speed, C0 ₂ level of outlet air (more gernerally, reading from C0 ₂ sensor 110), whether increased ventilation has been activated or deactivated and whether away -function has been activated or deactivated. The activated/deactivated status information can be stored as logical values (1 and 0, or 0 and 1, for example) .

Each element in the matrix has in addition to its parameter value a time stamp that indicates the latest update. In addition to the time stamp, or alternatively, a counter value can be stored .

In a normal use situation the size of the matrix may remain rather small. Six columns and 10 rows is only 120 fields in sum, for example, even if the time stamps or counter values are included .

Therefore, instead of using precise addressing it is safer to broadcast complete matrix or at least any changed parts of it at regular intervals and/or always whenever there are changes taking place.

Therefore, each window-fitted ventilation unit 50 is listening to the communication interface and compares matrix data it has received with matrix information stored in window-fitted ventilation unit 50. If window-fitted ventilation unit 50 receives data with a newer time stamp, or with a counter value indicates that a matrix element is more actual than the matrix element stored in window-fitted ventilation unit 50, it updates its own matrix and then broadcasts the data it received. In this manner, all window-fitted ventilation units 50 can be kept up to date and in a system having a size like this so called overhead can be kept relatively small. FIG 15A illustrates internal function of window-fitted

ventilation unit 50 at power-on. In start Al microcontroller 91 located on circuit board 82 starts to receive power from a voltage converter 98 and starts to execute its pre-programmed program code. After microcontroller 91 has started to execute its pre-programmed program code it initializes its built-in peripherals (such as CAN peripheral, PWM peripheral, I ² C peripheral and ADC periherals - these are the peripherals that may be required for controlling the fans 63, 64, reading the temperature sensors Tl, T2, T3, T4 and so forth) by calling subroutine ^Λ Initialize peripherals' in step A3. After peripheral initialization microcontroller 91 executes program code for initializing the operating system task in processing step A5. Task initialization creates and initializes task to be ready for execution. After processing step A5 the operating system starts the task in processing step A7.

FIG 15B illustrates the operation of window-fitted ventilation unit 50 after power-on. After microcontroller 91 has executed processing step A7 , it starts to execute the task (start step Bl) . On processing step B3 microcontroller 91 reads values from C0 ₂ sensor 110, relative humidity sensor 111 and temperature sensors Tl, T2, T3 and T4 using the microcontrollers 91 built-in analog to digital converter to convert the analog output voltages from the sensors to digital values which are then saved to the microcontroller 91 memory. After reading temperature sensors Tl, T2, T3 and T4 on processing step B3 microcontroller 91 checks whether any events (such as, a whether a button has been pressed or whether a new CAN message has been received) have occurred in processing step B5 by reading the event variable from its memory. Possible events are button 112, 113, 114 or 115 pressed and/or message received from CAN bus 93. If button pressed event has occurred, the microcontroller 91 reads from its built-in memory which button 112, 113, 114 and/or 115 has been pressed.

If button 112 is pressed the microcontroller 91 increases the duty cycle of pulse width modulation (PWM) signal which is produced by its built-in PWM peripheral. If button 113 is pressed the microcontroller 91 decreases the duty cycle of PWM signal which is produced by its built-in PWM peripheral .

Microcontrollers 91 PWM signal is used to control the rotation speed of the fans 63 and 64. Preferably, each of the fans 63 and 64 may be controlled separately.

When PWM duty cycle is increased the speed of respective fan 63, 64 increases and if the PWM duty cycle is decreased the speed of respective fan 62, 63 decreases.

Window-fitted ventilation unit 50 changes its state to enhanced state F13 if button 114 is pressed. "Enhanced state" corresponds to "increased ventilation status activated" of window-fitted ventilation unit 50.

If button 115 is pressed, window-fitted ventilation unit 50 changes its state to away state F15. "Away state" corresponds to "away-function activated" of window-fitted ventilation unit 50.

If CAN message received event has been posted in step E5, then microcontroller 91 parses the received message in processing step B5 (such as, for instance, if CAN message received event has been sent from interrupt shown in FIG 15E step E5 ) . If the message has newer group state or it is a control message for itself the microcontroller 91 changes the state of itself in the matrix according to the received message. If the received message is only a status message from another device of building ventilation system 200, it saves the other devices status to its place in the matrix.

In processing step B7 microcontroller 91 checks if there are changes in the matrix regarding current state of the devices of the building ventilation network 200.

Certain device states are described in FIG 16 for window-fitted ventilation units 50. Controlled outlet valves 303, power and data terminal 304 and data server 305 may have different states. These device states are in this document sometimes referred to as "status information" and sometimes as "operational state" of window-fitted ventilation unit 50. If the device state is different in the matrix than it currently is in the received status information, the window-fitted ventilation unit 50 updates the respective state according to the information in the matrix. This is referred to as "updating the register". Even though this preferred mode the

implementation is being described with matrix-based

implementation, basically any other suitable storage data structure in the register of microcontroller 91 could be used.

In processing step B9 microcontroller 91 reads its own column, where the state of window-fitted ventilation unit 50 and sensor information are stored, from the matrix and sends information on that column to CAN bus 93. After processing state B9,

microcontroller 91 jumps to execute processing state B3.

FIG 15C illustrates peripheral initialization subroutine that is used for turning on and configuring the peripherals (CAN peripheral, PWM peripheral and ADC peripheral) that are normally needed for the operation of the window-fitted ventilation unit 50 (peripheral CAN is needed of course only when the window- fitted ventilation unit 50 is connected to CAM bus 93.

Even though communication between window-fitted ventilation unit 50 and building ventilation network 200. The communication is described by using CAN bus 93 as the preferred communication interface. According to Wikipedia, CAN bus stands for Controller Area Network bus and "is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer. CAN bus is a message-based protocol, designed specifically for automotive applications but now also used in other areas such as aerospace, maritime, industrial automation and medical equipment."

When microcontroller 91 starts its peripheral initialization subroutine it starts to execute the program code from processing step CI. In processing step C3 microcontroller 91 initializes its built-in CAN peripheral by setting the CAN peripherals message buffers and clock settings . In CAN peripheral message buffer initialization step, microcontroller 91 sets which message buffers are intended for receiving and which are intended for transmitting CAN bus 93 messages . CAN peripheral clock settings which are pre-defined define the CAN bus baud rate and other timing related settings. Also CAN receive interrupt function, which is further described starting from processing step El (cf. FIG 15E) , is defined in this stage.

After CAN peripheral is initialized, microcontroller 91 reads the matrix from its non-volatile memory in processing step C5. Device ID validation is done in condition C7 by checking whether the device ID is in a valid range.

Each device in the building ventilation system 200 is identified by two different IDs: device ID and long ID.

Device ID is normally 7 bits long and it is used for identifying each device of the building ventilation system 200 that is connected to the same CAN bus 93. Long ID is normally 29 bits long and it is generated on each device. This long ID is used before the device has received the device ID from the device which has device ID 1. Device which has device ID 1 is

responsible of providing the device IDs to other devices connected to same CAN bus 93.

If the device ID is in valid range (this has advantageously been pre-defined, such as the range between 1 and 127) , the code execution continues to processing step C9 where microcontrollers 91 built-in PWM peripheral is initialized by pre-defined PWM frequency and duty cycle. On initialization of the PWM

peripheral a pre-defined value, read from the non-volatile memory of the microcontroller 91, is used for PWM duty cycle. PWM peripheral is integrated in the microcontroller 91, and is preferably used to control driver circuit 92 used to control the fans 63 , 64.

If the I ² C bus is used (such as, for connecting sensors to window-fitted ventilation unit 50) then it is initialized in processing step Cll after the PWM initialization processing step C9. According to Wikipedia, the Great Encyclopedia, I ² C stands for "Inter-Integrated Circuit, pronounced I-squared-C, which is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor, known today as NXP Semiconductors, used for attaching low-speed peripherals to computer motherboards and embedded systems."

I ² C settings are retrieved from the non-volatile memory of microcontroller 91. In stage C13 the button pressed interrupt, which is described starting from processing step Dl, is

initialized and configured to happen when button 112, 113, 114 or 115 is pressed. After processing step C15 microcontroller 91 continues to processing step A5.

If it is detected that the device ID is not in the valid range in checking step C7 then microcontroller 91 starts to execute processing step C17 where it starts to listen to CAN bus 93 if there are other devices existing on the CAN bus 93. Then microcontroller 91 enters to processing step C19 where it generates a 29-bit long ID, which is used to identify the device without valid device ID. The length 29-bit must be understood as a non-limiting example. Other lengths may be used as well.

After processing step C19 the device listens to CAN bus 93 for 5 s (for example, the length of the window-fitted ventilation unit 50 listening period may be chosen differently) in

processing step C21 to determine if there are other devices on CAN bus 93 which already have device ID value 1.

If microcontroller 91 receives CAN message in processing step C21 then on the condition C23 microcontroller 91 continues to processing step C25 where microcontroller 91 checks whether the CAN message received in processing stage C21 has a standard identifier having 11 bits, or long identifier (long ID) having 29 bits (the long identifier sometimes called as extended 29-bit long identifier) .

If the received CAN message is with long ID then microcontroller 91 jumps to execute processing step C17. If the received message is with device ID then microcontroller 91 sends a request for next free device ID message with long ID to CAN bus 93 in processing step C27. After receiving a device ID from a another device in the building ventilation system 200 having device ID number 1, in processing step C27 the microcontroller 91 checks whether the received device ID is valid. This checking is carried out in checking step C29. If the device ID is not valid then microcontroller 91 jumps to execute the processing step C17. If the device ID is valid then microcontroller 91 starts to execute the processing step C31 where it saves the device ID which was received in processing step C27 to the non-volatile memory of the microcontroller 91 and jumps to processing step C9.

If the there is no CAN bus 93 activity detected before condition C23 the microcontroller 91 continues its program execution to processing step C33. On processing step C33 it sends "I am node 1" message to the CAN bus 93 and so tries to inform other devices in the CAN bus 93 that it would like to have device ID number 1. After sending this request the microcontroller 91 continues to execute processing step C35 where it waits for 1 s (though any other waiting time period length may be used) . After processing step C35 the program comes to condition C37 where the microcontroller 91 checks if it has received a CAN message. If not, the code execution continues to condition C39 where it checks if the "I am node 1" -message is already transmitted five times (though any another number of repeated transmission can be used) . If not, the code execution jumps back to processing step C33. If "I am node 1" -message is transmitted five times (or the other defined number of times) then the microcontroller 91 continues to processing step C41 where it sets its device ID to 1. If in condition C37 CAN message received is true then code execution continues to condition C43 where it is checked whether the received message has a standard 11-bit long device ID or an extended 29-bit long device ID. If the received message has a standard 11-bit long device ID then microcontroller 91 jumps to execute processing step C19. If the received message has a long ID then code execution is continued to condition C45 where it checks if the microcontrollers 91 long ID is smaller than the received CAN messages long ID value. If it is smaller the microcontroller 91 continues to condition C39. Otherwise microcontroller 91 jumps to processing step C19.

FIG 15D describes a possible manner of handling interrupts in microcontroller 91. If button 112, 113, 114 or 115 is pressed, an interrupt happens inside the microcontroller 91 which in consequence stops the execution of the current code and jumps to execute the interrupt routine starting from processing step Dl.

When the "button pressed interrupt" occurs, microcontroller 91 posts a button pressed event in processing step D3 by changing the value of the event variable on microcontrollers 91 memory. After posting this event the microcontroller 91 reaches the end of button pressed interrupt D5 and continues to execute the code where it left of before the button pressed interrupt occurred.

FIG 15E describes a possible manner of handling interrupts in microcontroller 91. If the CAN peripheral of microcontroller 91 receives a CAN message from CAN bus 93, it creates an interrupt which stops the execution of the current code and jumps to start of CAN bus message received interrupt El. On processing step E3 microcontroller 91 transfers the CAN message out from the microcontrollers 91 CAN peripheral internal message buffer to the memory of microcontroller 91, where it is accessible by task in processing step B5. After the message has been transferred to the microcontrollers 91 memory the interrupt execution stops in E7 and it continues execution where it left of before the CAN message received interrupt.

FIG 16 describes certain device states of the window-fitted ventilation unit 50 and possible transitions between the device states. As explained above, the device states are in this document sometimes referred to as "status information" and sometimes as "operational state" of the window-fitted

ventilation unit 50.

Window-fitted ventilation unit 5 0 has different stages for its operation. When window-fitted ventilation unit 50 is powered up (state Fl), its state is not initialized (state F3) . In the not initialized state F3 the microcontroller 91 has not yet

initialized all the peripherals and tasks. After the program has executed processing step A5, the device state is changed from not initialized state F3 to initialized state F5. The window- fitted ventilation unit 50 goes automatically to running state F7 when the initialization state has been fully completed. This happens when the software reaches processing step B3. From start step Fl to until the window-fitted ventilation unit 50 has reached the running state F6 all the state transitions happens automatically without user interaction needed.

After the window-fitted ventilation device 50 has entered running state F7 and if the user presses button 115 the device enters enhanced state F13 where fan 63, 64 speeds are increased to achieve higher fresh air 20 and waste air 23 flow.

The window-fitted ventilation device 50 preferably returns automatically from enhanced state F13 to running state F7 after a pre-defined period of time.

If button 114 is pressed, the window-fitted ventilation device 50 enters the away state F15 where the fan 63, 64 speeds are decreased to decrease the fresh air 20 and the waste air 23 flow .

Transition from away state F15 to running state F7 happens when the user presses one of the buttons 112, 113, 114 or 115 or when a change state message is received trough CAN bus 93.

Transition from running state F7 to group function state F9 takes place when command message is received trough CAN bus 93 and if that command message is request for that specific device to change its state to group function F9. This request can be sent from, for example, computer or tablet 308, which is connected to building ventilation network 200 and/or to data server 305. In this manner, the computer or tablet 308 can be used to change operational state of the window-fitted

ventilation unit 50.

Transition from group function state F9 to running state F7 occurs preferably automatically after a pre-defined period of time. User input is received from one of the buttons 112, 113, 114 or 115 or control message is received from CAN bus 93.

The window-fitted ventilation device 50 preferably changes to defrost state Fll automatically, if it recognizes that the cross-counter-flow heat exchanger 62 has frozen or about to be frozen and it needs to be defrosted. This is in this document sometimes referred to as de-icing. For determining the need o de-icing condition of the cross-flow heat exchanger 62 the window-fitted ventilation unit 50 uses temperature sensors Tl T2, T3 and T4. After the device has recognized that the cross flow heat exchanger 62 has been defrosted (i.e. that the de- icing has been completed) , the window-fitted ventilation unit returns to running state F7.

Table 1 : States of window-fitted ventilation unit 50

State Device Description

state

0 Initialized window-fitted ventilation

unit 50 is initialized and

ready for running

1 Running window-fitted ventilation

unit 50 is running

2 Stopped window-fitted ventilation

unit 50 has been running

but is now stopped

3 De-icing Defreezing (or defrosting)

heat exchanger

4 Enhanced Increased ventilation i.e.

mode fans 63 and 64 are rotated

faster

5 Enhanced in Air inlet fan 64 is rotated

mode faster than air outlet fan

63

6 Enhanced Air outlet fan 63 is

out rotated faster than air

inlet fan 64

7 Error Table 2 : Group states

Certain different states of windows-fitted ventilation device are listed in Table 1. Certain group states of the building ventilation system 200 are listed in Table 2.

With group states states are meant according to which the window-fitted ventilation devices 50 of all windows-fitted ventilation devices 50 in the building ventilation system (i.e. in the group) are operated. Alternatively or in addition, it is possible to operate a subgroup of the group with a certain group state and another subgroup (that most preferably has no common members with the other subgroup) are operated with another group state .

Table 3 : Possible frame structure

Table 3 illustrates the possible frame structure for

communication in CAN bus 93.

DLC field determines how many bytes there is data on that specific message. Valid values are 0-8.

RTR field is not used in this communication scheme and its value is set always to 0.

Row 1 is explanation field for each column Row 2 is data le

llor 2 9-bit lo

ano! each data fi

Row 3 is message

transferring the data between the devices . It has the basic device state information

Row 4 is message which is transmitted in C33.

Row 5 is message which is transmitted in C27. This message is transmitted by device which wants to get device ID.

Row 6 is message which is transmitted in C27. This message is transmitted by device which has device ID value 1. This is response message to message which is described in row 5.

FIG 22 illustrates building ventilation system 200. Building ventilation system 200 comprises a number of devices such as ventilation windows 1 each equipped with a window-fitted ventilation unit 50, controlled outlet valves 303, server 305 and preferably at least one user interface panel 311. The appearance of user interface panel 311 that will actually be implemented may differ from that shown in FIG 22.

The devices may communicate wirelessly with each other. For this reason a wireless network 93' (cf. FIG 19) may be used. There exists a plenty of choice for suitable wireless network 93' . Alternatively to or instead of wireless network 93' , wired network such as a field bus, a building automation bus or a wire-based communication network such as the Ethernet, or even an optical network may be used. There exists a plenty of choice for such communication networks and in particular wired networks on the market. Particularly advantageously, CAN bus 93 (cf. FIG 19) may be used.

Data server 305 may be configured to save time series of the system matrix and may also serve as interface 308 enabling system control and analysing control application 312. Control application 312 is preferably accessible via the Internet or intranet. Control application 3,2 may be used on computer or tablet 308. Preferably, each device of the building ventilation system 200 (window-fitted ventilation unit 50, controlled outlet valve 303, user interface panel 311, data server 305) has wireless

transceiver for radio connection 309 and AC/DC power supply 306. However, as explained above, some or all of the devices may have a wire-based network or optical network connection, such as for CAN bus 93.

The number of window-fitted ventilation units 50 and controlled outlet valves 303 can be chosen based on the building or part of it, for example, based on the number of rooms apartment.

Preferably, each room has at least either one window-fitted ventilation unit 50 or one controlled outlet valve 303.

Controlled outlet valve 303 is preferably installed in each room with high ventilation needs. In a normal apartment or house, such rooms may include kitchen K, and/or toilet/bathroom/shower room KPH .

Preferably, at least one one window-fitted ventilation unit 50 is installed in each room.

FIG 23 illustrates building ventilation system 200 that differs from building ventilation system 200 shown in FIG 22 in that it has been configured to deploy a different power supply system and a different data transferring method. The graphical

appearance of control application 312 that will actually be implemented may differ from that shown in FIG 23.

In FIG 23 the data and power bus (CAN bus 93) has been drawn as a main line with branches. In practice, however, if CAN bus 93 is used, the topology would be shown as a bus. Therefore, the main line with branches as shown in FIG 23 should be understood as CAN bus (i.e. organized as a bus in which data is transferred in a pipeline in both directions) . CAN bus 93 can operate as a star network and, additionally, there are also other potential network topologies that could be used.

In building ventilation system 200 of FIG 23, each device

(window-fitted ventilation unit 50, controlled outlet valve 3 03, user interface panel 311, data server 305) is connected with the others with a power and data cable 83. The power and data cable 83 physically connects the devices with each other.

Furthermore, power and data terminal 304 may have been connected to the power and data cable 83, preferably as its last device. The power and data terminal 304 may contain AC/DC converter 306 for supplying needed power for the building ventilation system 200. Power and data terminal 304 may encompass data server 305 which may be connected on end point of the wire-based network or optical network connection, such to CAN bus 93.

FIG 24 and 25 illustrate a current state of the art building ventilation solution. Rooms of the building or of an apartment have been denoted as follows: K (kitchen), OH (living room), MH (bedroom), ET (corridor), KPH ( toilet/bathroom/shower room) .

The upwards arrows in FIG 24 denote the currently employed centralized solution. Air is removed from the building or the apartment from certain rooms, such as from kitchen K, and toilet/bathroom/shower room KPH by ceiling vents for which suction is generated by centralized ventilation system.

Replacement air intake is normally from vents in a wall or in a window .

The fresh air intake can be seen in FIG 25, as well as the air removal through the ceiling vents and centralized ventilation system, usually blowing removal air to the funnel or chimney.

Ventilation through fresh vents causes, especially during winter time, cold draught and loses a lot of energy since all waste air is going straight out from tha building or apartment.

FIG 26 illustrates a possible use scenario of the building ventilation system 200 according to the present invention. The window-fitted ventilation units 50 are most preferably installed in all rooms, except rooms with no windows, and possibly but not necessarily in kitchen K. Window-fitted ventilation unit 50 may also/or alternatively be installed in toilet/bathroom/shower room KPH.

In FIG 6, window-fitted ventilation unit 50 is installed in living oom OH and bedrooms MH. Controlled outlet valves 303 have potentially also been installed, in the example of FIG 26 in kitchen K, and/or toilet/bathroom/shower room KPH .

The idea of the building ventilation system 200 is to make the window-fitted ventilation units 50 to work together to implement the ventilation of a building or of an apartment. Even better, if the building ventilation system 200 is implemented so that not only the window-fitted ventilation units work together but also with the controlled outlet valves 303 (which preferably are controlled by the building ventilation system) , a distributed ventilation system can be installed. This is a convenient manner for implementing room-specific ventilation.

Furthermore, ceiling ventilation (controlled outlet valve 303) may be necessary only in the kitchen K. This enables great savings during the construction of the building or the

apartment .

The invention is not to be understood to be limited in the attached patent claims but must be understood to encompass all their legal equivalents .

List of reference numerals used:

R level defined by outer boundary of the frame

U outer side

S inner side

KPH toilet/bathroom/shower room

K kitchen

ET corridor

MH bedroom

OH living room

1 ventilation window

2 frame

3 inner sash

4 outer sash

5 glass pane (or glass element)

6 glass pane (or glass element)

7 light opening

8 hinge

9 frame cladding

10 intermediate space

11 pivot point

12 arm

13 arm

14 recess

20 fresh air

21 incoming air

22 outgoing air

23 waste air

50 window-fitted ventilation unit

51 inlet

52 outlet

53 inlet

54 outlet

55 condensate outlet pipe

55A inlet

55B outlet

56 filter chassis

back panel

cover panel

cover panel

cover panel

cross-counter-flow heat exchanger

Ά fresh air channel of the cross-counter-flow heat exchanger

B outlet air channel of the cross-counter -flow heat exchanger

fan (air outlet)

fan (air inlet)

transfer channel

suction channel

attenuation chassis

attenuation chassis

corner turnout

guide

attenuation material

fastening member

installing channel

guide

guide

electrical system

user interface / user interface panel

circuit board

power and data cable

fan power

escorting heater

C0 ₂ sensor cable

temperature sensor cable

relative humidity sensor cable

electronic circuit

microcontroller

driver circuit

CAN bus

' wireless network

CAN adapter

radio module antenna

graphical user interface

voltage coverter

supply voltage pin for I/O

LOW-level CAN bus line pin

HIGH-level CAN bus line pin

silent mode control input pin

fan connector

I2C connector

power connector

temperature sensor connector

UART and CAN connector

C0 ₂ sensor (C0 ₂ )

relative humidity sensor (RH)

button

button

button

button

building ventilation system

glazing bead

additional frame

controlled outlet valve

power and data terminal

data server (collects time series data and serves as interface )

AC/DC converter

AC power cable

computer or tablet

radio connection

DC power cable

user interface panel

control application (e.g. on a computer or tablet)