VENTILATION CONTROL ARRANGEMENTS FOR MEASURING AIR QUALITY WITH SENSORS MOVABLE FROM ONE ROOM TO ANOTHER
[0001] The invention relates to a ventilation control arrangement that comprises a control unit for controlling ventilation, a sensor for measuring air quality and means for transmitting the measuring result of the sensor to the control unit, whereby the control unit is adapted to control ventilation on the basis of the measuring result of the sensor.
[0002] EP publication 0 759 586 discloses a building automation system. The system uses sensors having for instance a temperature sensor, microprocessor and transmitter. From the sensor, measuring information is transmitted wirelessly to a central unit. Solutions of a corresponding type are also disclosed in WO publication 93/20495, US patent 5 927 599 and DE publication 19 700 762. All above-mentioned cases have the problem that the devices of the systems are quite complex and, therefore, the system is quite expensive. Further, it is quite difficult to make modifications to them and for in- stance when moving the sensor from one room to another, programming changes are typically required.
[0003] The object of the present invention is to provide an easily modifiable and versatile ventilation control arrangement.
[0004] The control arrangement of the invention is characterized in that it comprises a room assembly unit, to which the sensor can be connected, whereby the sensor and the room assembly unit together form a room unit, and the measuring result of the sensor is transmitted to the control unit from the room unit.
[0005] The essential idea of the invention is that a ventilation sys- tem has a control unit that receives room-specific information from at least one room unit. The room unit comprises a sensor and room assembly unit. The sensor is connected to the room assembly unit only when needed. Thus only the room assembly unit needs to store coded room data, for instance, and the sensor can be a simple device only providing a measuring result. There is no need to have a sensor in every room assembly unit, but it is enough that there is a sensor in the most important rooms depending on their use. When necessary, the sensor can easily be moved to a room assembly unit in another room. Thus, there is no need to place for instance quite expensive carbon dioxide sensors into every room. The room assembly unit can instead be placed in several rooms and when necessary, a carbon dioxide sensor is simply moved to the room assembly unit of another room.
[0006] The invention is described in greater detail in the attached figure that is a schematic representation of a ventilation system.
[0007] The figure shows the ventilation system of a small building, such as a detached house 1. The ventilation system can be controlled sepa- rately for each room, i.e. each room 2 has a supply air duct 3 and an exhaust air duct 4. In the rooms 2, the supply air ducts 3 end in supply air valves 5 and the exhaust air ducts 4 start from exhaust air valves 6. Thus, the amount of supply and exhaust air in each room 2 can be controlled. The system comprises a supply air blower 7 for blowing supply air and an exhaust air blower 8 for removing air. The supply air ducts 3 and the exhaust air ducts 4 are linked to exit and enter a distribution box 9 of ventilation.
[0008] A sensor 10 to measure the air quality of the room 2 is located in the room 2. The sensor 10 can be a carbon dioxide sensor, for instance, in which case it measures the carbon dioxide content of the air in the room. The sensor is installed in a room assembly unit 11. The sensor 10 and the room assembly unit 11 then together form a room unit 12.
[0009] The room unit 12 transmits measuring information measured by the sensor 10 to a control unit 13. The information from the room unit 12 to the control unit 13 can be transmitted wirelessly using a Bluetooth system, for instance. If desired, the information can also be transmitted over wire, in which case there is a cable connection from the room assembly unit 11 to the control unit 13.
[0010] The room assembly unit 11 can contain coded location information that is transmitted to the sensor 10 through contact pins, for in- stance, when the sensor 10 is fastened to the room assembly unit 11. A transmitter transmitting the measuring information to the control unit 13 can be in connection with the sensor 10 and thus, the sensor 10 receives location information from the room assembly unit 11 and transmits the location information together with the measuring result to the control unit 13. Then again, the transmission unit can also be adapted into the room assembly unit 11.
[0011] The room assembly unit 11 can thus be a versatile sensor rack provided with, for example, a transmitter unit or the like means. On the other hand, the room assembly unit 11 can be a simple mechanic framework or for instance a magnet which can be positioned on a wall or table, and to which the sensor 10 is connected. The room data can be coded in a simple room assembly unit by means of mechanic pins or protrusions, for example.
[0012] It is not necessary to have a sensor 10 in every room 2, but the sensor 10 is moved as necessary to the room where people are. This way, if the purpose of use of the room 2 changes, the sensor 10 can easily be moved as necessary. The system can thus be very easily modified, and it is not necessary to purchase a relatively expensive carbon dioxide sensor for each room.
[0013] The room unit 12 comprises means expressing that there is a sensor 10 connected to the room assembly unit 11. When the sensor 10 is connected to the room assembly unit 11 , a message can be arranged to be sent from the room unit 12 to the control unit 13, informing that there is a sensor 10 arranged in the room assembly unit and that the ventilation in the room 2 is to be adjusted on the basis of the measuring results of the sensor 10. When there are no sensors 10 in the room assembly unit 11 , the ventilation in the room 2 is adjusted according to a predetermined general instruction. [0014] The distribution box 9 of ventilation comprises control means, and a control command for maintaining suitable supply and exhaust air amounts in each room is transmitted from the control unit 13 to the distribution box 9.
[0015] Thus, when the sensor 10 detects that the carbon dioxide content, for instance, rises, the control unit 13 adjusts the amounts of supply and exhaust air of the ventilation system and at the same time maintains a balance in the ventilation of the entire building 1. The adjustment is most preferably implemented in such a manner that the pressure in the distribution box 9 is kept constant, which means that the system measures with a pressure sensor 14 the pressure level of the distribution box 9 and tries to maintain a constant pressure level. The distribution box 9 has adjustable valves, whereby when increasing the ventilation in a room, the supply air duct 3 valve of the room in the distribution box 9 is turned towards open and the exhaust air duct 4 valve of the room in the distribution box 9 is opened correspondingly. To maintain a balance, the supply air and exhaust air duct valves of the other rooms and/or the power of the supply air blower 7 should be adjusted. The adjustment can naturally also be done by adjusting the adjustable valves 5 and 6 located in the room 2.
[0016] Allowed values are set for the pressure level, so adjustment can also be done such that the pressure level of the distribution box 9 decreases slightly, if the pressure level decrease remains within the allowed lim-
its. The system monitors the pressure levels on the supply and exhaust sides and tries to maintain either a constant pressure level or a constant pressure difference between the supply and exhaust sides. The system can also have pressure sensors adapted specifically for each room, in which case the pres- sure difference is measured at the entrance of the supply air duct 3 and the exhaust air duct 4 in proximity to the room space 2 so as to be able to determine that the exhaust air blow exceeds the supply air blow. The system can also be used to adjust the temperature of the room 2, in which case floor heating, for instance, serves as a slow basic adjustment and air heating reacts to quick changes.
[0017] In connection with the sensor 10, there may be a push button, for instance, with which it is possible to transmit a message to the control unit 13 that you want to increase ventilation temporarily in the apartment in question. The sensor 10 may instead of or in addition to carbon dioxide also measure such variables as temperature, carbon monoxide, smoke, radon, moisture, air pressure or pressure change. When necessary, a safety alarm can be sent onwards through the control unit 13 as a result of such a measurement. A display can also be located to the sensor 10 to show for instance the temperature, carbon dioxide content, ventilation in litres or some other relevant variable of the room 2.
[0018] The system can also be fitted with air and/or moisture recir- culation, i.e. if the sensor 10 detects that there is no carbon dioxide in the exhaust air of a room, the air can be recirculated. A recirculation air valve 15 is then opened and the air can flow along an return air duct 16. If it is detected that there is too much carbon dioxide in the exhaust air duct, the air is naturally not recirculated. The system can also be used to recirculate moisture, i.e. it is for instance possible to recirculate moisture from a shower room after a shower to a room, in which the air is too dry. In such a case, the moisture content of the exhaust air is monitored and the moist air to be recirculated is led to a certain room. In such a solution, the heat recovery cell should naturally be capable of transmitting moisture.
[0019] The figure and the related description are only intended to illustrate the idea of the invention. The invention may vary in detail within the scope of the claims. Thus, information can also be transmitted from the room unit 12 to the control unit 13 wirelessly utilizing radio or infrared technology, for instance. One sensor 10 can thus measure one or more properties. On the
other hand, the room assembly unit 11 can be formed such that a plurality of different sensors 10 can be connected to it.