A COOLING MODULE FOR DECENTRALLY DISPOSED VENTILATION SYSTEMS

The prior art

The invention relates to a cooling module, in particular for the cooling of outside air for decentrally disposed ventilation systems.

In modern buildings, at schools, offices and common rooms, there is a great need for ventilation. The need varies depending on the size of the room, its thermal load and the number of persons who are to be present in the room.

Ventilation systems may be established in various ways. For instance, many systems are built as central ventilation systems equipped with a set of air channels which convey the outside air into the rooms, and remove the spent exit air from the rooms. This type of ventilation systems makes it necessary to provide many and long air channels which result in pressure drop, and the system must therefore be dimensioned such that it can supply all the rooms with fresh outside air, and so that it can also compensate for the pressure drop through the channels. Dimensioning of such systems is frequently difficult, and, as a result, there are examples of systems having an inferior function in the form of poor ventilation or a high noise level.

Along with the ventilation, there is also the desire of being able to reduce the loss of heat from the rooms. Therefore, ventilation systems are frequently equipped with heat recovery facilities, such as heat exchangers. This makes it possible to extract heat from the exit air and to supply this heat to the fresh outside air.

Such heat exchangers may be constructed in several ways, where passive cross-flow or counter-flow heat exchangers frequently occur. The heat exchangers may also be equipped with liquid coupled recovery faces.

In those periods where the outdoor temperature is high, or there is a great incident thermal radiation into the building, it will be advantageous to cool the outside air such that the temperature of the injection air is reduced. In central ventilation systems having heat exchangers with liquid coupled recovery faces, the system may be extended with a cooling machine. Such a system is described on page 256 of "Ventilations Stabi" published by "Tek- nisk Forlag A/S" 1988.

Ventilation systems for an entire building may also be composed of decen- tral ventilation systems, which are arranged in each of the rooms in which ventilation is desired. The decentral systems are very compact, and the capacity is adapted to the room.

These systems obviate the need of running a plurality of air channels through the building, and it is possible to dimension the system such that it is almost noiseless. The systems provide great flexibility, and it is moreover possible to install the systems in both new and old buildings.

Decentral ventilation systems may also be equipped with heat exchangers for heat recovery. An example of such a system is shown on the applicant's homepage www.airmaster.dk, where it is described in an installation and operation manual designated Airmaster Il 300.

In addition to a plurality of other components, the shown system is equipped with a counter-flow heat exchanger for heat recovery, but also with a bypass valve, whereby the heat recovery may be disconnected, and the fresh air is sent directly into the room. This function is useful in particu-

lar in case of a great incident solar radiation, or when the outside air temperature is high.

The shown system, on the other hand, cannot cool the outside air to a de- sired temperature before injection into the room.

Air condition systems are also frequently constructed as decentral systems to be mounted in a room in which they can either heat or cool injected air. Air condition systems are provided with a cooling circuit which may be switched for heating or cooling. Such systems are frequently mounted on an external wall or in connection with a window. For reasons of noise and space, the ventilator and the compressor of the cooling system are mounted externally in a box, and, internally, an injection ventilator is disposed behind a grating. Noise nuisances frequently occur both outside and inside.

The object of the invention

It is the object of the invention to remedy as many drawbacks of decentral ventilation systems as possible, and this is achieved by a cooling module which comprises a housing provided with a cooling circuit having components for the filtration and cooling of outside air, and in that the cooling module is configured to be arranged indoors and to be coupled together with and to cooperate with a decentral ventilation system likewise arranged indoors, and in that the cooling circuit and the air flow through the cooling module are controlled by the ventilation system.

By arranging the cooling module in a housing provided with an air filter and a cooling circuit, and constructing the housing so that it may be coupled together with and cooperate with a decentral ventilation system, and by controlling the cooling circuit and the air flow through the cooling module

from the ventilation system, a supplier achieves the advantage of simultaneously being able to increase the possibilities of subsequent mounting at existing customers, to increase the flexibility in case of new projects and to be able to offer the user better comfort in the room by cooling the outside air in a simple and financially advantageous manner.

When, as stated in claim 2, the housing is configured with an engagement face which fits a mounting frame, and with another engagement face which fits the ventilation system, it is ensured that the cooling module may be in- serted in a simple manner between the mounting frame and the ventilation system.

When, as stated in claim 3, the engagement faces are provided on the cooling module such that the one engagement face comprises connection stubs for outside air and exit air, said stubs fitting into openings in the walls, and the other engagement face comprises openings for outside air and for exit air, said openings fitting the connection stubs of the ventilation system, it is ensured that the cooling module may be connected between the mounting frame and the ventilation system without problems.

When, as stated in claim 4, the housing is divided into a section for outside air and a section for exit air separated by a mounting plate, and the section for outside air is provided with an air filter and with an evaporator, and the section for exit air is provided with a compressor, a condenser, a drying filter and a baffle, it is ensured that the outside air and the exit air may be kept separated from each other, and that the outside air may be conveyed through the evaporator and the exit air through the condenser.

When, as stated in claim 5, the housing is additionally provided with a set of mounting plates, which are fixedly connected with each other, and all the components of the cooling modules are secured to these plates, said plates

standing on the bottom of the housing, it is ensured in case of a repair or service job that all the components may be taken out at the same time by dismounting the bottom.

When, as stated in claim 6, the cooling system is composed of the stated components, all of which are standard components for the manufacture of cooling systems, an efficient, thoroughly tested and financially attractive solution is achieved.

When, as stated in claim 7, the air flow through the cooling module is determined by the speed of rotation of the injection and exhaust ventilators of the ventilation system, it is ensured that the air flow is determined by the ventilation need, and also a cooling module saving is achieved, because no ventilator for the operation of the cooling module has to be incorporated.

Finally, it is expedient, as stated in claims 8, 9 and 10, to arrange the cooling circuit such that it is activated by a relay switch inserted into the voltage supply to the cooling compressor, said switch being controlled by the ventilation system and activated when the bypass process is activated and the valve is opened, and the flow rate of the air is greater than or equal to 1 m/s, and that the cooling circuit is deactivated when the flow rate of the air is less than 1 m/s, or for reasons of safety when the surface temperature of the condenser exceeds 60 ⁰ C.

The drawing

Preferred exemplary embodiments will be described more fully below with reference to the drawing, in which

fig. 1 shows an expanded isometric view of a complete system with ventilation system, cooling module and wall mounting frame,

fig. 2 shows an expanded drawing of a complete system, in which the cover plates on the cooling module and on the ventilation system are removed, and

fig. 3 shows a functional diagram, indicating the cooling circuit and the air circuit through the cooling module and the ventilation system,

Description of the exemplary embodiments

Exemplary embodiments shown in fig. 1 , fig. 2 and fig. 3, respectively, will be described below.

Fig. 1 shows a complete system consisting of a cooling module 1 with the housing 2, a ventilation system 18 and a mounting frame 19. The system is shown in a separated state, so that the engagement faces 3 and 22 as well as the lugs 35 and 37 and the holes 36 and 39 are visible. The connection stubs 4, 5 and 25, 26, respectively, are visible on the engagement faces 3 and 22. The arrows A indicate the path of the air flow into and out of the system.

Fig. 2 shows the system seen from above and without cover plates. A section of a wall 29 is shown with the hole 24 for outside air and the hole 23 for exit air and the mounting frame 19 placed in position after mounting.

The housing 2 of the cooling module is shown, indicating the engagement face 3 and the engagement face 6. The engagement face 3 is provided with the connection stubs 4 for outside air and 5 for exit air, said studs being provided with seals (not shown) of resin, which fit into the pipe liner (not shown) in the wall holes 23 and 24. The engagement face 6 is provided with openings 7 for outside air and 8 for exit air for receiving the connection stubs 25 for outside air and 26 for exit air on the ventilation system 18.

The housing 2 of the cooling module is divided into a section 9 for outside air and a section 10 for exit air by a mounting and partition plate 27, so that the air in the two sections cannot be mixed. A transverse mounting plate 31 is secured to the plate 27. The plates 27 and 31 serve as mounting plates, since all the components of the cooling module are secured to these plates.

The mounting plates stand on the bottom of the housing 2 and are secured on the internal side to the engagement faces 3 and 6 of the housing by screws. In case of repair, the bottom of the housing is removed, the mounting plate 27 is loosened from the engagement faces of the housing, and then the mounting plates with all the components may be taken out downwards.

The section 9 for outside air is provided with a replaceable air filter 11. The filter is a filter of standard type 5. Further, an evaporator 13 is provided, which forms part of the cooling circuit 33. The evaporator 13 is of the slat type and mounted on the plate 31 , so that the air passes the slats.

The section 10 for exit air is provided with a cooling compressor 14, which circulates the coolant in the cooling circuit, a drying filter 28, a condenser 15 for discharging the heat from the coolant when the exit air passes by, as well as a baffle 30 which is to deflect the air through the section 10, so that the air is distributed better across the entire surface of the condenser.

The ventilation system 18 is shown in fig. 2 without a cover plate. The engagement face 22 is shown with the connection stubs 25 for outside air and 26 for exit air. The figure moreover shows a ventilator 20 for outside air, a ventilator 21 for exit air as well as a bypass valve 32. The valve 32 makes the air flow go around the heat exchanger 40.

Fig. 3 shows a functional diagram of the cooling module 1 and of the venti-

lation system 18. The air flow A is introduced as fresh outside air into the outside air section 9 of the cooling module at the arrow 41. The air flow is sucked in by the ventilator 20 and passes en route a filter 11 and an evaporator 13, which cools the air flow. At the pressure side of the ventilator 20, the air flow is passed via the bypass valve 32 to the room which is to be ventilated at the arrow 42. From the room, the spent air is sucked into the ventilation system at the arrow 43 and further through the heat exchanger 40 to the ventilator 21 , from which it is pressed through the exit air section 10 of the cooling module. Here, the air flow passes a condenser 15, where it absorbs the heat from the cooling circuit before disappearing out into the atmosphere at the arrow 44.

Also shown is a diagram of the cooling circuit 33 arranged in the cooling module 1. The cooling compressor 14 compresses and presses the hot gas through the condenser 15, where the gas is cooled, following which it expands through the drying filter 28 and the capillary tube 34. The cooled gas is then heated in the evaporator 13, which absorbs the heat from the added outside air. A standard coolant, such as R134 A, is used, but also other coolants may be used. The effect of the cooling module is determined by the task, but a cooling module of 1100 w will e.g. be able to give a temperature reduction of 10 °C with an air renewal of 300 m ³ /h.

The cooling circuit 33 is activated by a relay switch, which is inserted into the voltage supply of the compressor 14. The relay switch is controlled by the control unit of the ventilation system, which contains inter alia a program element for the control of the bypass process which controls the bypass valve 32. The valve is opened or closed steplessly by the bypass process. A requirement for the cooling circuit to be activated is that the bypass process must be activated, and that the rate of the air flow must be greater than or equal to 1 m/s. If this condition is meet, the relay switch is activated and thereby the compressor and the cooling circuit.

The cooling circuit is deactivated when the rate of the air flow is less than 1 m/s, or if the surface temperature of the condenser 15 exceeds 60 ⁰ C.

When the system is to be mounted, the mounting frame 19 is fitted with screws in the holes 38. The mounting frame is arranged across the holes 23, 24 which have been made in the wall 29. Then, the cooling module 2 is fitted by passing the connection stubs 4 and 5 into the holes 23 and 24 and by moving the lugs 35 into the holes 36 and clamping them with screws.

The ventilation system 18 is mounted subsequently by passing the lugs 37 into the holes 39 of the ventilation system. To counteract the torque on the mounting frame 19, an angular profile (not shown) may be applied to the upper edge of the ventilation system for attachment in the ceiling.

The assembled system is dimensioned and constructed such that its physical size, its design and the low noise level, which does not exceed 35 dB at full load, make it extremely useful as a decentral system in offices and other rooms in which persons are present.