FI100132B - Arrangement in connection with an air handling unit - Google Patents

Description

100132

Arrangement in connection with an air handling unit

The invention relates to an arrangement in connection with an air handling unit, comprising means for controlling the exhaust and supply air through the air handling unit, at least a two-stage heat recovery apparatus and means for introducing additional heat or cooling power into the supply air.

Such arrangements are now common in building air conditioning solutions. Energy is transferred from 10 air to air mainly indirectly through heat exchangers. Ventilation plants today are almost invariably equipped with heat recovery equipment. To an increasing extent, indirect evaporative cooling has also entered the market, where the exhaust air is cooled by humidifying it. The temperature effect then passes through the recovery phase to the supply air, which cools down. Depending on the hygiene requirements, technical requirements and space solutions, the heat recovery device can be a plate heat exchanger, a rotating rotor, a medium-operated coil combination or a heat pump.

Despite the good efficiency of heat recovery devices, additional heat is usually necessary in ventilation plants so that the supply air temperature is not too low, especially if the amount of energy transferred from the exhaust air has to be limited due to the fogging of the exhaust air. The additional heat is traditionally introduced into the supply air after the heat recovery device by a water coil or electric coil. However, the use of electricity for air heating is questionable and the trend will become more pronounced in the future. The exhaust air side of the heat recovery devices 30 becomes fogged when the moisture in the exhaust air condenses on the surface of the recovery device, if its surface temperature is on the frost side. Depending on the relative humidity of the exhaust air, this occurs when the outside temperature is -15 ° C or colder. For example, the defrosting of the plate heat exchanger takes place in such a way that part of the supply air 2 100132 is directed past the plate heat exchanger or the supply air is prevented from alternately entering the different blocks of the exchanger, whereby the warm exhaust air defrosts the fogged parts. During the defrosting phase, the heat recovery efficiency decreases. The operation of the antifreeze phase and the prevention of the auxiliary heating coil from freezing require both special automation operations and electromechanical devices to carry out the operation.

The object of the invention is to provide an arrangement by means of which the disadvantages of the prior art can be eliminated. This is achieved by means of an arrangement according to the invention, characterized in that the means for supplying additional heat or cooling power to the supply air comprise at least one additional heating or cooling device / cooling device or a heating-cooling device adapted to change the temperature of the exhaust air and thus indirectly affect the supply air temperature via the heat recovery apparatus 20.

The advantage of the invention is, above all, its good basic heat recovery efficiency and very high municipal thermal energy efficiency in the heating and / or cooling phase. In addition, the total solution is inexpensive and easy to operate and reliable and consumes little electricity.

Good thermal energy efficiency in the heating phase is based on the possibility of using low-level thermal energy such as waste heat or condensing heat, which may even be free energy unless it can be utilized in another way. The low electricity consumption is based on the fact that the radiator surfaces are efficiently utilized at all stages, when there are no components causing additional air resistance in the air flow. The plate heat exchanger is not equipped with an electricity consuming liquid pump. Conventional components in the supply and exhaust air flow can complement the supply in an advantageous manner. In winter, the supply air flow passes through the first stage of the heat exchanger, heated by the exhaust air, after which it passes to the next stages of recovery, whereby the temperature reaches a basic level, which as such may be sufficient. If this is not enough, for example in the case of air heating, the supply air passes through the auxiliary heating coil. Since the auxiliary heating coil is connected in series with the exhaust air heating coil, the control circuit can be common.

10 In summer, the supply air flow can bypass the heat exchangers, for example via a bypass route, if you do not want to change the status. If the system is equipped with exhaust air humidification cooling, the supply air cools in stages as it passes through the heat recovery stages. If the temperature 15 is not low enough, it is possible to equip the supply air with a cooling coil.

In winter, the exhaust air flow first passes through the last heat recovery stage on the supply air side, whereby the exhaust air temperature decreases. The radiator in the exhaust air stream 20 then heats the exhaust air before it proceeds to the next heat recovery stage, releasing its additional heat energy and any thermal energy remaining from the previous stage or a part thereof to the supply air via the recovery device.

. ·. 25 In summer, it is possible to cool the exhaust air flow by humidifying either in one step in connection with the heat recovery stages or in separate humidifiers in the direction of the exhaust air flow before the recovery stages. If this is not enough, the heating coil in the exhaust air stream can be used as a cooling coil. Additional efficiency can be achieved by providing the supply air with either a separate cooling coil or a combined heating and cooling coil connected in series with the exhaust air coil.

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The essential difference from conventional operation is that the temperature of the additional energy may be at a lower level, because in normal operation there is no risk of freezing, while the temperature difference between the substance to be heated and the heat transfer agent can still be favorable. With the conventional arrangement, the temperature of the heating medium in the inlet pipe cannot be lower than 30-40 ° C, which is the normal temperature of the water when the ventilation is stopped. The design temperature for normal operation is generally +60 ° C in and +40 ° C out. The invention 10 makes it possible to make good use of an energy source with a temperature of, for example, +25 ° C, in which case the corresponding temperatures can be +25 ° C in and +20 ° C out, since the purpose is to heat the exhaust air above 0 ° C, but lower than the heat-15 space leaving the room. At the same time, the automatic operation can be simplified in terms of frost protection, anti-fogging and possibly temperature control. A variable water flow can also be run through the auxiliary heating coil or coils without the risk of the water freezing.

The invention will now be described in more detail with reference to the preferred embodiments shown in the accompanying drawing, in which Fig. 1 shows a schematic side view of a preferred embodiment of the arrangement according to the invention, Fig. 2 shows a schematic side view of another embodiment of the arrangement embodiment, Fig. 4 is a schematic side view. a fourth embodiment of an arrangement according to the invention, Fig. 5 shows in principle a side view of a fifth embodiment of an arrangement according to the invention, Fig. 6 shows in principle a side view 35 a sixth embodiment of an arrangement according to the invention, 5 100132 Fig. 7 eighth embodiment, Fig. 9 shows a schematic side view of an alternative embodiment of the embodiment of Fig. 8, Fig. 10 shows a schematic side view of a second alternative embodiment of the embodiment of Fig. 8, and Fig. 11 shows a schematic side view of an embodiment of an alternative embodiment of the invention.

In Fig. 1, reference numeral 1 denotes the first stage of the heat recovery arrangement in the direction of supply air flow, and reference numeral 2 denotes the second stage. Em. the steps are plate heat exchangers. Reference numeral 3 denotes an auxiliary heating device 20 placed between the recovery steps, for example an auxiliary heating coil which, if desired, operates at a low temperature level, such as waste or condensing heat, which is supplied to the coil via connecting pipes 8. It should be noted that Fig. 1 is simplified with respect to the actual structure, so Fig. 25 should be understood only as a reference.

Reference numeral 14 denotes in Fig. 1 the casing part of the air handling unit, reference numeral 15 denotes the supply air manifold and reference numeral 16 denotes the exhaust air or separate air manifold. In this context, separate air means air other than ventilation exhaust air, which transfers energy to the supply air or whose change of state indirectly affects the state of the supply air. As an example of separate air, outdoor air or a mixture of outdoor air and indoor air can be mentioned. Reference numeral 17 denotes a possible supply air filter 35 and reference numeral 18 denotes a possible exhaust air filter. Reference numeral 19 describes a possible supply air shut-off damper and reference numeral 20 a possible exhaust air shut-off damper. Em. in addition to the details, the apparatus can be equipped with conventional components such as, for example, an air mixing section, electrical supply, etc.

Figure 1 clearly shows the basic idea of the invention, i.e. that the means for introducing additional heat or cooling power into the supply air comprise at least one heating device or cooling device 3 arranged in the exhaust air flow or separate air flow between steps 1, 2 of the heat recovery apparatus. and thus indirectly affect the supply air temperature via the heat recovery equipment. Figure 1 shows a further application possibility. Reference numeral 27 denotes a device consuming thermal energy, and reference numeral 28 denotes a device which dissipates heat, respectively. The heat energy consuming device 27 and / or the heat dissipating device 28 is preferably connected 20 in the same liquid circuit in series with the heating or cooling device 3 and further to a point in the liquid flow direction as seen at a point before the heating or cooling device 3.

In the embodiment according to Figure 2 is shown. 25 a heat recovery arrangement, in which reference numerals 1 and 2 describe the steps of the heat recovery apparatus, reference numeral 3 for an additional heating coil, and reference numeral 8 for connecting pipes. Reference numeral 13 denotes an air flow bypass duct in which the damper 12 controls the air flow. The damper 12 can be used, for example, in a summer operation situation where it is not desired to transfer thermal energy to the supply air.

Fig. 3 shows the steps of the heat recovery apparatus by reference numerals 1 and 2 and the heating air coil 7 100132 in the exhaust air flow coming between the recovery steps by reference numeral 35 3. Reference numeral 4 is a TU-heating radiator supply air flow in a liquid side pipe is indirectly connected in series with the active inlet air temperature of the heating radiator 3. Both radiators 5 can be controlled, for example, by means of one common automatic control circuit. In this application, the radiator 3 indirectly affects the supply air flow through the heat recovery equipment and the radiator 4 in turn directly because it is located in the supply air flow.

Fig. 4 shows the arrangement according to Fig. 1, to which an exhaust air humidification device, denoted by reference numeral 5, has been added. Em. the humidifying device may be a separate humidifier, a humidifying nozzle or a recovery device provided with humidifying arrangements. The solution can be repeated in connection with each phase of the recovery device or with respect to the direction of exhaust air flow before the recovery device.

It is clear that the devices 27 and 28 can also be connected to the embodiments according to Figures 2-4 in the same way as shown in Figure 1.

Fig. 5 shows the arrangement according to Fig. 4, in which the auxiliary heating coil 6 has two functions, i.e. heating and cooling. Em. the functions can be performed by means of the same battery 6.

Figure 6 shows two stages 1 and 2 of the recovery apparatus and a humidification device 5. The combined radiator 6 enabling heating and cooling is connected in series, i.e. on the liquid side, in series with the second combined radiator 7 30 in the supply air flow by means of pipes 11. With this arrangement, it is possible to enhance the effect in both the heating and cooling phases. In this embodiment, the radiator 6 acts indirectly on the supply air flow through the heat recovery equipment and the radiator 7 in turn directly because it is located in the supply air flow.

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Fig. 7 shows the basic idea of the solution according to Fig. 1 implemented with rotating recovery cells, which are described by reference numerals 21 and 22. Other operating alternatives can be implemented in a corresponding manner. The radiator 5 3 is located in the exhaust air flow.

Fig. 8 shows the basic idea of the solution according to Fig. 1, implemented by means of a medium-operated battery solution. The coils in the supply air flow are described by reference numerals 23 and 24 and the coils in the exhaust air stream 10 by reference numerals 25 and 26, respectively.

In connection with the solution according to Fig. 8, it can be stated that a particularly advantageous embodiment is obtained by connecting the radiators 23-26 in series to the same flow circuit 15 on a countercurrent basis, as shown in Fig. 9. In addition, the radiators 23 and 24 shown in Fig. 10. Of course, it is also possible to implement the above-mentioned structural alternative also in the opposite direction.

The heating device and / or the cooling device 3 can also be arranged in the bypass duct 110 in the manner shown in Fig. 11. Figure 11 is based on Figure 8. Figure 11 shows only the exhaust air side of the radiators 25, 26, the remainder 25 of Figure 11 embodiment corresponds to the embodiment of Figure 8. In this embodiment, the air flow can be controlled to pass through the bypass duct 110 through the heating device 3 by means of the control damper 111, or alternatively directly so that the air does not flow into the bypass duct 110 but to the heating device 3. In addition, it is possible to design the structure in such a way that one of the radiators of the heat recovery equipment can be bypassed. This detail is also shown in Fig. 11, which shows a second control damper described by reference numeral 112, which can be turned to the positions shown in Fig. 35, whereby the air flow can be controlled in the desired manner. Figure 11 shows arrows showing different airflow options.

The devices 27 and 28 according to Figure 1 can also be connected to the applications according to Figures 5-8 in the same way as shown in connection with Figure 1.

The application examples presented above are in no way intended to limit the invention, but the invention can be modified completely freely within the scope of the claims. Thus, it is clear that the arrangement 10 according to the invention or its details do not necessarily have to be exactly as shown in the figures, but other solutions are possible. It should be noted, for example, that although the figures show solutions using one coil placed between the recovery stages and one coil arranged in the supply air flow, this is not the only possibility, but it is possible to use this. also several radiators, etc. Although the figures mainly describe plate heat exchanger applications, the invention is also well suited for the other previously mentioned devices or combinations thereof.

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Claims (6)

100132 An arrangement in connection with an air handling unit, comprising means (15, 16, 19, 20) for directing exhaust and supply air through the air handling unit, at least a two-stage (1,2) heat recovery device and means for introducing additional heat or cooling power into the supply air, characterized in that the means for supplying additional heat or cooling power to the supply air comprises at least one heating device and / or cooling device (3,6) or additional heating device for supplying additional heat or cooling capacity bound to the heat transfer fluid between the stages (1,2) of the heat recovery apparatus 10; a cooling device adapted to change the temperature of the exhaust air and thus indirectly affect the supply air temperature via the heat recovery equipment. An arrangement according to claim 1, characterized in that it comprises means (12, 13) by means of which the exhaust air, supply air, separate air or exhaust air can be directed past the heat recovery equipment. An arrangement according to claim 1 or 2, characterized in that it comprises at least one heating or cooling means (4,7) arranged in the supply air flow, the liquid side (s) (9) of which are connected in series with the heating in the exhaust air stream or in the separate air stream. - or / and a cooling device (3,6), said assembly being arranged together to provide both an indirect and a direct effect on the supply air temperature. • ·. Arrangement according to one of the preceding claims 1 to 3, characterized in that the arrangement comprises at least one heat energy consuming device 35 (27) and / or heat transfer device (28) connected to the same liquid circuit in series with at least one heating or cooling device. (3,6) and in the direction of liquid flow as seen at the point before the heating and / or cooling device (3,6). Arrangement according to one of the preceding claims 1 to 4, characterized in that at least one humidification device (5) for cooling the air is arranged in the exhaust air stream or in the separate air stream. Arrangement according to Claim 1, characterized in that the heating and / or cooling device (3, 6) is arranged in a separately closable bypass duct (110). 100132 Patentkxav