A ceiling of this kind is known from European patent applications EP-A-0 255 739 or EP-A-0 294 909 in which a livestock building, which is provided with an air- permeable ceiling with a pressure chamber in the garret under the ridge of the building is described. The air is led into the garret in which a certain excess pressure is created so that the air penetrates the ceiling and flows into the livestock building.

Suction from the livestock building may, e. g. take place through the floor as illustrated in EP-A-0 255 739 or EP-A-0 294 909. The air supply, and potentially the suction channels, may be provided with a baffle for control of air circulation.

In EP-A-0 255 739, the ceiling is comprised by wooden fibreboard panels through which air from the garret may be diffused down into the room below. This covering of the ceiling is used for many types of constructions due to its acoustical properties, as well as to aesthetic and financial considerations.

This ceiling-based type of ventilation is thus relatively inexpensive and efficient but mainly utilised in connection with livestock buildings.

A ventilated ceiling construction for environmental control of a clean room, e. g. in a laboratory, is described in US-A-3,975,995. According to this disclosure, the ceiling consists of two layers; the upper layer is made up by a mixed array of filter panels and blank panels, and the second ceiling layer is perforated. The first, upper layer defines a dirty air barrier by filtering the air through to the space between the two

layers. From this clean air plenum, the clean air is pressed through the second dropped ceiling layer and into the clean room. Similar to the ventilation systems in EP-A-0 255 739 or EP-A-0 294 909, this ceiling construction is provided with a discharge in the floor of the enclosure to be ventilated. This ceiling construction is complicated in its design and is suitable for clinically clean air supply in laboratory rooms, e. g. clean rooms, in which the requirements to the cleanliness of the air are extensive.

The ventilation principle applied in these known ceiling constructions is a so-called piston displacement where a massive air supply from the entire ceiling or the surface of the wall is carried out with the discharge of air taking place on the opposite surface. However, this method of ventilation is insufficient when used for comfort ventilation, e. g. with respect to assembly rooms (cinemas, theatres, receptions, restaurants etc.), sports centres, housing, office facilities (large rooms or small rooms or computer rooms), cafeterias etc.

Climate control is to be understood as ventilation and potentially cooling of the air for establishment of the desired climate comfort.

In order to meet the requirements of ventilation and comfort, it is common to have relatively complicated ventilation fittings installed in office facilities etc. Meanwhile, it is difficult and extremely expensive to create a ventilation installation which is adapted to the individual requirements such as e. g. the interior characteristics, accommodation space in an office building, an office location etc. When adapting ventilation to the current conditions, any subsequent rearrangement/refurnishing will create the risk of the ventilation, and thereby the indoor climate, being completely jeopardised.

These ventilation systems may furthermore not be desirable for architectural and utilisation reasons since they often comprise components which are quite visible in the rooms of the buildings and may limit utilisation of the space. This may be

particularly true during subsequent installation of ventilation systems in older buildings.

If the purpose of the building/the room is changed, the ventilation system may only be changed through complete reinstallation of the ventilation system which is usually not practically feasible since the installation of a ventilation system with ventilation channels etc. are often integrally installed in a building.

Based on this, the object of the invention is to create a ventilation system and a method of climate control of the initially mentioned kind, which are suitable for comfort ventilation and which may be adjusted to the relevant requirements of ventilation in a room.

This object is achieved by a system of the initially mentioned kind in which the ceiling comprises a predetermined combination of one or more active and one or more passive sections corresponding to the actual interior configuration of the room where the active sections allow for air-penetration from the pressure chamber into the room contrary to the passive sections which do not allow air penetration, said predetermined combination being determined in accordance with the size and location of the convection sources in the room.

In a second aspect of the invention, a method of controlling the climate in a room through ventilation of the room is provided, whereby air is blown into a pressure chamber from which the air penetrates a ventilating ceiling at low impulse blowing into the room from which the air is subsequently sucked out, whereby the air is prevented from penetrating the one or more passive sections in a predetermined pattern of passive and active sections in the ceiling and thus only penetrates through the ceiling at the one or more active sections in the ventilating ceiling which allows for penetration, said predetermined pattern being determined in accordance with the size and location of the convection sources in the room.

A third aspect of the invention relates to a ceiling for use in connection with a system and a method of climate control of a room, where the ceiling is made up by panels accommodated in suspension means, and where the ceiling comprises a predetermined combination of one or more active and one or more passive sections depending on the relevant characteristics of the room, said sections being made up by one or more active or passive panels, respectively, where the active panel allows penetration of air from the pressure chamber into the room contrary to the passive panel which is impermeable, said predetermined combination being determined in accordance with the size and location of the convection sources of the actual lay-out in the room.

By a ventilation system according to the invention, a simple and efficient system for climate control of a room is obtained in which the sections of the ceiling are used as air supply surface in connection with comfort ventilation of a room. These sections form the ceiling in accordance with the convection sources in the room so that customised appropriate ventilation takes place in the areas of the room in need thereof. In this manner, an optimal utilisation of the amount of air used for ventilation of the room is obtained. The one or more active sections of the ceiling are penetrable whereby low impulse blowing (also referred to as inlet air diffusion) of air from the pressure chamber is obtained which creates a steady flow from the supply surface towards the areas of accommodation/convection sources of the room.

Usually, by mixing with the air in the room by entrainment, the result will be a draft in the room. This may be avoided by a system according to the invention. By the invention, environmental and constructional rationality may be obtained, since the number of components to be included in the structure of the room will be reduced, whereby the construction process is simplified, just as environmental rationality may be obtained by applying natural materials including the material of the ceiling panels.

Thus, a complete solution may be obtained by means of which several functions are integrated in one solution resulting in rationality in terms of manufacturing time, installation, and the financial burden.

By a ceiling according to the invention, various fittings in the ventilation and other installations may be removed from the room and hidden above the ceiling or in the panels of the ceiling, such as sprinkler systems, electrical installations etc. In this manner, it is possible to create a more homogenous ceiling surface.

In the preferred embodiment of the system, the control means comprises control of the amount of airflow, speed of the air supply, temperature, and/or humidity. In this manner, it is possible to control the indoor climate accurately, just as the impact of the variations in the outdoor climate may be compensated for.

In one embodiment of the invention, the control means may even include controlling the discharge suction means. In this manner, the circulation of air in a room and the replacement of air may be controlled. The discharge suction means may be located immediately under the ceiling or at floor level in the room. A third option is to have one or more suction points with a combination of suction means at the floor level and near the ceiling. This provides an additional possibility of influencing air circulation or suction in the room.

In a preferred embodiment, the distributor plate is located in front of the air supply means so that good distribution of the air supply into the pressure chamber is obtained.

In the preferred embodiment, a dropped ceiling is provided, whereby a pressure chamber is created above the ceiling. In addition, the ceiling is preferably insulated allowing for a difference in temperature between the top and the bottom side thereof.

In the preferred embodiment of a system according to the invention, the air supply is led into the pressure chamber at a lower temperature than the desired room temperature, preferably at a difference in temperature of approx. 8 to 10 °C, but even lower temperatures may also be applied if appropriate by the conditions. In this manner, diffuse ventilation is obtained since cooled air penetrates the ceiling/air

supply surface, which will sink into the room due to the difference in temperature. If the temperature difference is approx. 1 to 2 °C, low impulse ventilation may be created and the air will be mixed with the air in the room. Contrary to the known ventilation systems, greater air-based cooling may be achieved by the invention. By a system or a ceiling according to the invention, cooling of up to typically 50 to 60 W/m2 or more, e. g. up to 100 W/m2, may be obtained.

In a preferred embodiment of the system, a suitable pressure loss above the active panels in the ceiling is e. g. between 0.3 to 2.0 Pa., preferably 0.7 to 1.0 Pa., so that penetration of air through the ceiling panels is ensured, said panels preferably being made of wood-wool/cement, just as reasonable air distribution over the air inlet surface is ensured whilst a controlled the air supply via the panels and not through leaks in the ceiling into other rooms is ensured. With the wood-wool/cement panels, a particularly advantageous inlet of air into a room is obtained in comparison with known air supply surfaces due to the surface structure and thickness of the panels. By the invention, it will be possible to provide a change of the air approx. 8 to 10 times an hour or more in the ventilated room (s).

In order to ensure good air distribution in the pressure chamber, the speed at which the air is supplied into the pressure chamber is approx. 1 to 2 m/s, and preferably not more than 3 m/s. The airflow speed of the inlet air supply may be increased to 3 m/s by using a distribution plate in front the of the air supply inlet.

By a ceiling according to the invention, the one or more active panels are preferably made of a compressed wooden fibre material encompassed by cement. In this manner, inexpensive panels with good acoustical absorption and handling properties are obtained. Furthermore, the one or more passive panels are preferably made as a laminated sheet comprising a layer of compressed wooden fibre material encompassed by cement, which is provided with an air barrier on the pressure chamber side. In this manner, it is possible to create a uniformly looking ceiling

when looking at it from below since the active and the passive panels will not be visible.

In the preferred embodiment, the air barrier is comprised by a fully sealed insulating mat. In this manner, good acoustical insulation is obtained since regulations and requirements to building construction concerning e. g. mineral wool insulation may be met whilst at the same time letting the impenetrable foil ensure that mineral fibres are not released into the ventilated air out into the room. It should be noted that the pressure chamber is located inside the climate protection screen of the building, i. e. inside the thermal insulation.

In the preferred embodiment of a ceiling according to the invention, it is a modular configuration with individually replaceable panels. In this manner, a particularly simple"standard"ceiling may be obtained by means of which it is very simple, quick and thereby inexpensive to rearrange the active and passive sections so they meet the actual ventilation requirements of a room.

In order to keep false air-flows from penetrating the ceiling at the joints of the panels of the ceiling, the active and passive panels are provided with a rectangular basic shape with abutting lateral edges designed with complementary overlaps, and preferably in such a manner that the first lateral edge is provided with a longitudinal recess and the abutting lateral edge on the adjacent side is provided with a longitudinal tongue. In this manner, an overlap is provided at the joint so that the passive panel edge will prevent air penetration. The joint may be replaced by a tongue-groove joint instead.

Alternatively or as a supplement, the joint (s) between two panels or between a panel and an abutting surface may be provided with sealing means such as cover plates, guides or the like. In this manner, false air-flows may efficiently be prevented if the joint overlap between the panels is not sufficient or possible, e. g. along the rim of the

ceiling, around pillars in a room or in relation to ceiling rails, e. g. a relation to a dropped ceiling.

In the preferred embodiment of a ceiling according to the invention, the area of the active sections is approx. 1/8 of the total ceiling area. This area may be smaller or larger depending of the actual needs for ventilation. In this manner, good air distribution is ensured in the room. In addition, adjustment possibilities for control of the air supply pattern are ensured.

By a fourth aspect of the invention, a method of installation of a climate control system in a room is described, said method comprising identification of the convection sources in the room, especially size and location, and planning of the ventilating ceiling on the basis hereof, including determination of a pattern of active and passive panels and installation of the ceiling and potentially installation of the air supply and discharge suction means of the climate control system if not already installed.

By according to this method, conducting a preliminary analysis of the requirements for ventilation, a climate control system according to the invention, the ceiling may be composed in accordance with the relevant requirements. This method of installation may be utilised in relation to both installation of new ceilings and reconstruction of old ceilings in accordance with redefined needs for ventilation in a room. By a method according to this aspect of the invention, a simple and hitherto unknown method of installation of ventilated ceilings is provided.

In the following, the invention is described in more detail with reference to the drawings, in which fig. 1 shows a schematic view of a system for climate control according to the invention,

fig. 2 shows a schematic view of a ceiling according to the invention, seen from above, fig. 3 shows a first embodiment of a panel joint in a ceiling, and fig. 4 shows a second embodiment of a panel joint and the construction of a passive panel.

The principles of a system for climate control according to the invention are shown in fig. 1 for ventilation/climate control of a room 1. A pressure chamber 2 is provided above the room 1. The room 1 and the pressure chamber 2 are separated by a partially air-penetrable ceiling 3, which is preferably mounted in the entire length of the room. At the outer surfaces 4 of the building, inlet means 5 are arranged for supplying fresh air into the pressure chamber 2 and discharge suction means 6 are arranged for discharging air from the room 1. In fig. 1, the climate control system is shown in relation to ventilation of one room 1 but the pressure chamber may also be a joint chamber for more neighbouring rooms in a building 4.

In connection with the air supply means, control of air humidity, temperature, and airflow inlet velocity may be provided according to the requirements, just as the air supply ensures a slight excess pressure in the pressure chamber. The airflow and the rate of air exchange cycles in the room may also be regulated by controlling the inlet air supply and discharge suction. The flow rate of the air supply into the pressure chamber should be selected with respect to the pressure loss at the ceiling plates and the airflow velocity of air in the room. If the airflow speeds are too high in the room, this will be perceived as a draught and thus have a negative effect on the comfort of the room.

The ceiling 3 has a number of passive sections/panels 7 and active sections/panels 8 which are installed in a predetermined combination in relation to the relevant location of convection sources 9 in the room 1, where the active sections 8 allow penetration of air from the pressure chamber 2 into the room 1 contrary to the passive sections 7 which do not allow air penetration.

The ceiling 3 is a module construction with a number of panel plates, e. g. installed in a mesh of ceiling profiles in a false ceiling. The active sections are made up by plates 8 manufactured in a compressed wood fibre material encompassed by cement, so- called Troldtekt (R) ceiling plates. These plates are air-penetrable and do at the same time posses good acoustically dampening properties. The passive sections are made up by laminated plates 7. These are manufactured from a compressed wood-wool cement board 7a corresponding to the active plate 8, which is provided with an air barrier 7b on the back (see fig. 4). The air barrier 7b is made up by a fully sealed insulating mat, such as a so-called Rockfon0 plate. In this manner, good thermal and acoustical insulation of the ceiling 3 is obtained, just as this laminate plate 7 ensures a uniform ceiling surface in the room 1.

The convection sources 9 may be all kinds of heat sources, e. g. accommodation areas, computer equipment or other machinery, heaters, coolers etc. The ceiling panels 7,8 are installed in a pattern corresponding to the relevant individual requirements for ventilation of the room 1, as shown in e. g. fig. 2.

Fig. 2 shows a schematic view of a ceiling 3 according to the invention seen from the pressure chamber 2. As is apparent from fig. 2, a baffle plate 10 has been placed in front of the air supply inlet 5 so that incoming air is distributed in the pressure chamber 2, whereby more harmonic air distribution is obtained.

The active and passive sections 7,8 in the ceiling 3 are, as shown in fig. 2, installed in a predetermined pattern. This pattern is determined based on a preliminary analysis of the ventilation requirements prior to the installation of the ceiling and installation of the climate control system. This preliminary analysis comprises registration of the size and location of the convection sources 9 (see also fig. 1) based on which the pattern of active and passive sections in the ceiling may be determined.

This method of determination of the combination of the passive and active sections of the ceiling may be used in relation to both new installations and to existing

installations of ventilation systems in order to achieve as optimal and comfortable a ventilation of the room as possible with respect to the actual interior lay out and use of the room.

The ceiling panels 7,8 are provided with lateral edges 12,13 designed with mutually complementary shapes so that a certain overlap is obtained which reduces the risk of leaks and an optimised control air supply is obtainable. As shown in figs. 3 and 4, the lateral edges of a panel may be designed with a protruding tongue 13,13'fitting into a corresponding chamfer 12 or recess 12'in the adjacent plate. The embodiment may either be a wedge-shaped tongue 12 and a chamfer 13, as shown in fig. 3, or a rectangular tongue 13'and a corresponding recess 13', as shown in fig. 4. It will also be possible to have a combination of more joint geometries. Corresponding overlaps may also be established at the other edges of the plates. This overlap does not only improve the sealing of the joints but also makes it easier to mount them to the ceiling since the lateral edges make it easier to position the panels correctly.

The joint shown in fig. 4 is particularly simple since the tongue 13'and the recess 12'are created by displacing the fibre plate 7a and the air barrier 7b during lamination so that a tongue 13'and a recess 12'will appear automatically at the two lateral edges of the plate 7.

As a supplement to such an overlap, it is possible to include a sealing plate 11 as shown in fig. 3. This sealing plate 11 may be a self-adhesive tape, a lists or the like.

By the invention, a system for climate control is provided which is well suited for comfort ventilation in many different types of rooms. Thus, it is realised that a system for comfort ventilation according to the invention may be used for ventilation/climate control of office facilities, computer rooms, theatre and cinema rooms, receptions, restaurants, museums, libraries, assembly rooms, cantinas, dressing rooms, sport centres, swimming baths, skating buildings, exercise facilities etc.

The invention is described in relation to a ventilating ceiling surface in one room but it is understood that it may also be utilised to ventilate more rooms by means of one joint pressure chamber. Apart from that, it has been realised by the invention that a climate control system according to the invention may be implemented via other room surfaces, e. g. a wall surface such as a partition wall. By the term"ceiling"used in this specification and in the accompanying claims also includes a wall-oriented solution, which is considered an equivalent solution in relation to the invention.