EP0298996B1 - Process and installation for air conditioning of rooms - Google Patents

Abstract

The air conditioning system for rooms is based on regulating the fresh air volume fed to the room and extracting used inside air from the upper air layers of the room. In this process at least approximately fresh air isothermal to that of the room is introduced into the room in a laminar manner from the ceiling region (8). The rate of flow of the fresh air introduced supports the formation of partial flows having dynamic characteristics specific to the room. Preferably the fresh air in the ceiling region is introduced in the vicinity of internal walls of the room facing the facade walls (7). A volume flow regulator (3) is controlled by the temperature measured at the laminar diffuser (6). Preferably a heat exchanger (5) is connected to the fresh air duct (1) in the ceiling region, downstream of which is connected a diffuser (6). The fresh air, which is heated virtually to room temperature in the heat exchanger (5) flows into the room from top to bottom with an essentially laminar flow. The comfort of the air conditioning plant is very distinctly improved by adapting the temperature of the room air by means of the fresh air in the heat exchanger (5) and the introduction of isothermal fresh air into the room at a low speed.

Description

The invention relates to a method for air conditioning and a device for performing the method.

From DE-C-915 386 a generic device for air conditioning a relatively large hall is known, in which apparently unregulated fresh air above a first false ceiling leads to air supply lines, which are designed as pipes projecting vertically downwards into the hall, and exhaust air between the first and a second intermediate ceiling arranged below the same and provided with suction openings is pulled off. The air supply lines have openings in such a way that two openings of adjacent supply lines are directed towards one another, so that the kinetic energy of the inflowing air is destroyed in vortices which form.

In this way, in very large rooms, where the openings of the supply lines are high above the ground, pulling effects in the occupied zone are avoided since the air loses its kinetic energy before it reaches the ground.

In rooms of normal size such as living rooms or offices, however, turbulence caused by fresh air supply covers the entire room and cannot be kept away from the lounge area.

From FR-A-2 126 601 a device for ventilating stables is known, with which the main aim is to remove ammonia-containing gases from the ceiling area. The fresh air is fed to the distribution shafts through parallel ducts under the ceiling and apparently warmed somewhat by heat exchange with the room air near the ceiling. However, an actual climate control is not possible with this facility.

GB-A-2 029 004 also shows a device for ventilation of stables with a false ceiling, above which exhaust air is discharged through parallel ducts and on the underside of which fresh air supply is provided, further ducts are provided which have longitudinal slots on the undersides through which the supply air exits in the stable. Heat exchange occurs between the supply air and the extract air, but only to a very small extent between the room air near the ceiling and the supply air. The volume flow can be regulated in two stages. Here too, active temperature control is obviously not possible and is also not intended.

The invention is based on the object of specifying a method and a device for carrying it out, with which regulated and adequate heating or cooling is also possible for rooms of normal size, without the need for quickly supplied tempered, e.g. B. relatively cold fresh air stronger, as unpleasant drafts currents would arise.

This object is achieved by the invention as characterized in the claims.

According to the invention, the fresh air supplied, before it flows into the room, is only exchanged at room temperature by means of heat exchange with no or almost no mass exchange aligned. This not only has the advantage that the flows that may arise through the introduction of fresh air are felt much less strongly and, above all, much less disruptively because of the almost identical temperature with the room air, but also that the fresh air, since it is not blown directly into the room, but first adjusted in temperature by heat exchange, can be supplied with a much larger temperature difference. However, the required heating or cooling output, which is largely provided by the heat exchanger, is achieved with a much smaller volume flow than would be possible with the small temperature difference customary in known methods.

Such a method and such a device have considerable and serious advantages over known devices. First and foremost, the comfort properties of the air conditioning system are significantly improved so that it is practically not perceived by the people in the room, let alone perceived as annoying. This property is a result of the supply of isothermal fresh air into the room with only a low flow rate. Used and heated room air automatically rises in the room and is removed from there. If greater temperature adaptation performance is to be achieved, a heat exchanger is installed upstream of the diffuser, which is attached in the ceiling area, so that in this case the fresh air entering the room from the diffuser has already largely compensated for its original temperature gradient compared to the room air in the heat exchanger. The fresh air entering the room itself in no way exerts a cooling or heating effect. This air serves practically exclusively for the supply of fresh air and is led into the room in a largely laminar manner from above through the diffuser. From there, the air distributes itself according to the room's own dynamics, i.e. according to the occurring and possibly changing circumstances, without the strong and therefore disruptive air currents being noticeable.

Because of the smaller amounts of the incoming and outgoing air, there are smaller cross sections for the supply lines required, which results in space and cost savings. Due to the division of functions, there is also a significantly improved total energy requirement, which is, for example, only about 40% of the energy requirement of conventional systems with otherwise identical conditions.

Another advantage of the calmed air flow in the room is the greatly improved purity of the room air. The contamination of the room air due to air turbulence and high flow velocity is reduced.

Since the fresh air supply is no longer carried out at several points at a high speed that can be felt by the room occupant, but at a greatly reduced speed on one side of the room, there is much greater freedom in furnishing the rooms.

Finally, the use of a heat exchanger designed directly as a ceiling element saves overall height, since separate air ducts in the ceiling area and thus an additional suspended ceiling are unnecessary. Since no double floors are required for the air conditioning system, this area can be kept free for other installations, for example, exclusively for electrical installations. Because of the lower overall height of this facility, a lower overall room height can be maintained in the buildings, which is the case with larger building heights to significant improvements in building utilization, in extreme cases to additional floors within a given height.

The fresh air volume can preferably be controlled by temperature measurements in the area of the diffuser. As a rule, the diffuser will be located near the volume regulator, making installation easy and cost-effective. No separate room thermostats or other sensors are required within the air-conditioned room. Additional features and further advantages of the invention result from the following description.

Fig.1

die schematische Ansicht eines zu klimatisierenden Raumes mit den Hauptbestandteilen der erfindungsgemässen Raumklimaeinrichtung,

Fig.2

eine Aufsicht auf den Raum gemäss Figur 1 mit der Anordnung der Wärmetauscher im Deckenbereich,

Fig.3

den Schnitt 3-3 aus Fig.2, und

Fig.4

das Ausführungsbeispiel eines By-Pass-geregelten Heizsystems.

The invention will now be explained in more detail based on preferred exemplary embodiments with the aid of the drawings. Show it:

Fig. 1

the schematic view of a room to be air-conditioned with the main components of the room air conditioning device according to the invention,

Fig. 2

1 is a top view of the room according to FIG. 1 with the arrangement of the heat exchangers in the ceiling area,

Fig. 3

the section 3-3 of Figure 2, and

Fig. 4

the embodiment of a by-pass regulated heating system.

According to the example shown, the air conditioning system is connected to a fresh air duct 1 and an exhaust air duct 2. A volume regulator 3 is arranged in the fresh air duct 1. The fresh air duct 1 and the exhaust air duct 2 are covered by an installation ceiling 4. In the room to be air-conditioned, a heat exchanger 5 can also be provided, which in the example is designed as a ceiling element. If only low temperature adaptation performance can be achieved, the separate heat exchanger can be dispensed with.

As FIG. 2 shows in detail, in the example the fresh air duct 1 is connected directly to the inlet fins 5A of the heat exchanger, which at the other end merge into the return fins 5B. The outputs of the return lamellae 5B lead in parallel to a diffuser 6, which allows the fresh air to enter the room downward from the ceiling in accordance with the arrows A as a laminar flow. The diffuser 6 is preferably arranged on a side of the room which is opposite a window or facade side 7 of the room. In larger rooms, the diffuser is preferably arranged in areas close to the passageway, that is, preferably not above work or lounge areas.

Figure 3 shows the arrangement of the heat exchanger designed as a ceiling element on the ceiling 8. It is the formation of the inlet fins 5A and the return fins 5B as rectangular tubes and their mutual arrangement directly recognizable on the ceiling 8. The geometry and dimensions of the heat exchanger fins, which act as static cooling elements, set an average surface temperature of the ceiling, which is approximately equal to the average room temperature. With very large heat exchange loads, the efficiency of the cooling fins can be increased by increasing the free surfaces inside the duct.

For so-called high-performance zones, as can be seen in the right part of FIG. 3, the inlet fins 5A and the return fins 5B with small air exchange openings, e.g. B. be provided with slots 9, which accelerates the heat exchange process between the lamella wall and the ambient air surrounding the lamella in the vicinity of the heat exchanger. Under no circumstances will there be a direct supply of fresh air to the lounge area of the room. Rather, a type of micro flow is formed exclusively in the surface area of the lamellae. This improves the efficiency of the heat exchanger 5.

The fresh air led from the fresh air duct 1 via the volume controller 3 into the inlet fins 5A of the heat exchanger 5 loses part of its temperature gradient with respect to the ambient air via the fins of the heat exchanger, which preferably consist of a metal or another good heat-conducting material. When they return via the return lamella 5B, there is additional heat potential from the fresh air emitted to the room air via the heat exchanger. At the outlet of the return lamellae 5B, the fresh air which is almost matched to the room air temperature in the manner described above is introduced into the room via the diffuser 6. The fresh air entering the room from the diffuser should differ by a maximum of 1 degree C from the room temperature in the lounge area. The exit velocity of the fresh air emerging from the diffuser is of the order of 0.15 m / sec. It is therefore significantly lower than the exit speed of the fresh air introduced into the room in conventional air conditioning systems, which is approximately 1 to 3 m / sec.

The fresh air flowing out of the diffuser 6 flows down into the room, where it forms a supply of fresh air. Caused by the diffuse heat sources distributed over the room, the fresh air flows horizontally to the heat sources and heats them vertically to the ceiling, where it flows along the ceiling elements to an outlet 10 which merges into the exhaust air duct 2.

A warm air flow directed upwards results in a supply air flow which is branched off directly to the side from the fresh air flowing in from the diffuser 6. Larger flow rolls are formed, which, however, cause practically no turbulence, but rather develop their own dynamics in the room, so that main flows are present in the room get supported. Such main flows are the fresh air flowing down from the diffuser 6, branches to diffuse heat sources, further the flow of the fresh air directed towards the facade, finally the upward flow supported in the facade area by natural heating via the windows and the backflow in the ceiling area along the heat exchanger 5 to the room air outlet 10. Despite the practically laminar introduction of fresh air into the room, there is a very good air exchange within the entire room. This is primarily due to the measures described with regard to optimal use of the room's own dynamic.

The air conditioning can take place both in terms of cooling and for heating the room, or in quasi-isothermal operation for ventilation. Especially when heating, it can be useful to supply separate warm air and fresh air flows to the system and to regulate the air mixture in the diffuser area. The mixing takes place in a bypass 20 to the heat exchanger 5, as indicated in FIG. 4. Fresh air is fed directly to the bypass at a low temperature of, for example, 12 degrees Celsius. Air, for example, is heated to 38 degrees C via the heat exchanger 5. In the diffuser 6, the mixture is regulated to 21 degrees C, so that a room temperature of 22 degrees C is established. The control is carried out by a control valve 21 in the bypass 20, with a temperature sensor 22 in the area of the diffuser 6 a control device 23 cooperates and switches the motor 24 of the control valve 21 depending on the temperature.

The combination of static cooling surfaces on the heat exchanger 5 with laminar air inlet via the diffuser 6 and the use of the dynamics for the fresh air supply to the room result in a low room air speed comparable to the non-air-conditioned room and a uniform room air temperature distribution in the lounge area. The system operates extremely quietly and can also be used at high heat loads, especially if the heat exchanger fins are provided with the aforementioned micro-openings 9 to improve the heat exchange. No additional ducts or installation lines are required inside the room. In the typical example, the height of the heat exchanger fins is approx. 15 cm, so that the normal room height for non-air-conditioned rooms can be kept practically unchanged. So there is no need for double ceilings, which require additional room height in conventional air conditioning systems. Due to the intrinsically dynamic room air flow, which essentially runs from bottom to top, and by largely avoiding a cross flow with contaminated air, the pollution in the room air is kept extremely low.

The regulation of the fresh air supply via the volume controller 3 takes place with a view to a constant outlet temperature in the diffuser 6. In a preferred exemplary embodiment, the temperature of the primary air, ie the fresh air supplied in the fresh air duct 1, is +12 degrees Celsius, the exhaust air in the exhaust air duct 2 has a temperature of +27 degrees Celsius, while the room temperature is +24 degrees Celsius. The difference in temperature between the primary air and the exhaust air is 15 degrees Celsius here. In contrast, in current air conditioning systems with direct introduction of the cooled fresh air into the room with a differential temperature of max. 8-10 degrees worked, which results in greater air turbulence and thus a higher flow velocity in the lounge area and thus the unpleasant disturbing side effects.

In detail, the desired outlet temperature and thus room temperature is determined by an automatic volume flow adjustment, i.e. achieved by a temperature-volume cascade control. The temperature sensor leading the system, possibly with a measuring transducer, is integrated in the laminar flow diffuser 6. The control system works on the principle of a variable volume flow system "VVS".

By directly arranging the heat exchangers 5 on the on-site ceiling 8, for example with the aid of mounting rails 13 according to FIG. 3, the ceiling with its heat storage capacity can be incorporated directly into the heat exchange system. This has an additional stabilizing effect on the overall system and its control system and increases the efficiency of the heat exchange.

In a modification of the described preferred embodiment, the heat exchanger can also be arranged in other suitable areas of the room. It is also important in this case that the fresh air supplied via the fresh air duct 1 first passes through the heat exchanger and is only introduced into the room after it has warmed up to almost room temperature.

Although a material with good heat conductivity, e.g. offers a metal, it can also be made of other materials, e.g. made of plastic.

The use of such air conditioning is not limited to the aforementioned office or business premises. The device described can also be used to advantage in test laboratories or production rooms where a balanced climate, in particular constant temperatures, is required.

Claims (8)

1. A method of air conditioning by controlling the volume of fresh air supplied to the room and drawing off internal air from the upper air layers of the room, the temperature of the supplied fresh air and the air in the room being approximated to one another by a heat exchange of the fresh air with the upper air layers of the room before the then at least approximately room-isothermal fresh air is introduced with a laminar flow from the ceiling of the room with such a low flow velocity that only the formation of inherent dynamic partial flows resulting from existing diffuse heat sources in the room is supported, the minimum flow volume of supplied fresh air being set by a minimum value determined by air-hygiene regulations and otherwise heing controlled according to the outlet temperature or room temperature.
2. A method according to claim 1, characterised in that, once the minimum flow volume value has been reached in a sequential control, a temperature adaptation of the supplied fresh air is carried out.
3. A method according to claim 1 or 2, characterised in that the outlet velocity of the fresh air is limited to 0.15 m/s by a corresponding control of the flow volume.
4. A method according to one of claims 1 to 3, characterised in that the outlet temperature of the fresh air deviates from the room temperature in the occupation area by 1 °C at the most.
5. A device for carrying out the method according to one of claims 1 to 4, with a fresh air duct (1) for supplying temperature-regulated fresh air, an air outlet connected to the fresh air duct and an exhaust air duct (2), characterised in that the fresh air duct (1) is volume-controlled by means of a volume control (3) according to the outlet temperature or room temperature and the air outlet is constructed as a diffusor (6) arranged in the ceiling area and is connected to the fresh air duct (1) via a heat exchanger (5), which is also arranged in the ceiling area and comprises a plurality of parallel, spaced, tube-like feed vanes (5A) and return vanes (5B).
6. A device according to claim 5, characterised in that the heat exchanger (5) extends over the entire ceiling area.
7. A device according to claim 5 or 6, characterised in that a fresh air bypass (20) is associated with the heat exchanger (5), which fresh air bypass together with the heat exchanger (5) opens into the diffusor (6) and is provided with a valve (21), which is controlled by a control element (23) as a function of a temperature sensor (22) arranged in the region of the diffusor (6).
8. A device according to one of claims 5 to 7, characterised in that small apertures (9) are provided in the downwardly facing wall regions of the tubular feed vanes (5A) and return vanes (5B), so that a reinforced heat exchange takes place with layers of air in the immediate vicinity of the vane wall.

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