Method for improving energy recovery of intake and exhaust gas heat exchanger of a

Abstract

A method for controlling operation of an intake air heat exchanger and an exhaust gas heat exchanger of a combined cycle system of an air conditioning and ventilation system, the method comprising: supplying at least one intake air flow and / or at least one exhaust gas flow of the air conditioning and ventilation system to one or more heat exchangers, the medium flows through the one or more heat exchangers. The temperature difference delta T value between the flowing temperature and the backflow temperature of the medium of each heat exchanger is measured. Medium flow through the associated heat exchanger is set such that a delta T value of the associated heat exchanger is adjusted to a target value.

Description

Technical Field

[0001] The present invention relates to a method, an apparatus and a control system for operating an intake air heat exchanger and an exhaust gas heat exchanger of a combined cycle system for an air conditioning and ventilation system. Background Art

[0002] In order to achieve good energy efficiency in an air conditioning system or a ventilation system, a combined cycle system with heat exchangers in an intake air flow and an exhaust gas flow is provided, and these heat exchangers are connected to each other through a hydraulic circuit. Through these heat exchangers, in the case of heating, heat is extracted from the exhaust gas and supplied to the intake air, or in the case of cooling, heat is extracted from the intake air and can be supplied to the exhaust gas. For example, in a conventional system, the air side temperature, the medium side temperature, and the feed rates to the intake air heat exchanger and the exhaust gas heat exchanger are respectively measured so that the medium flow rate circulating in the heat exchanger adapts to the air side mass flow rate in a continuously regulated manner. However, this requires relatively high costs because a relatively large number of sensors are needed, and the regulation of the medium flow rate through the heat exchanger must be adjusted and optimized based on numerous measurement values for each specific application and each individual system. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a method and a system that can ensure efficient recovery of the heat of the exhaust gas or dissipation of heat from the intake air ( "recovery" of the cold of the exhaust gas), and the method and the system can be used together with one or more individual heat exchangers for the exhaust gas and the intake air respectively in the case of different air conditioning systems and ventilation systems.

[0004] According to the present invention, a method is provided in which one or more heat exchangers are respectively connected to one or several exhaust gas flows of an air conditioning and ventilation system and one or more heat exchangers are connected to one or several intake air flows of the air conditioning and ventilation system. For each heat exchanger, the temperature difference ΔT between the flow temperature and the return temperature of the heat exchanger is determined, and the medium flow rate through the relevant heat exchanger is set in such a way that the ΔT value of the relevant heat exchanger is adjusted to a target value.

[0005] In one embodiment, for example, in each case, a heat exchanger is provided in the intake air flow and a heat exchanger is provided in the exhaust gas flow, and the setting of the medium flow rate through the heat exchanger is completed by adjusting the rotational speed of at least one speed regulating pump.

[0006] In other embodiments, where, for example, more than one heat exchanger is arranged in one or more intake air streams and / or more than one heat exchanger is arranged in one or more exhaust air streams, a ΔT control valve can be assigned to each heat exchanger, and the flow rate through the associated heat exchanger can be set by this control valve in such a way that the value of the temperature difference ΔT is adjusted to a pre-fixed or dynamically scalable target value. Thus, efficient energy recovery is achieved in a particularly simple manner solely by temperature measurements at the heat exchanger.

[0007] By controlling at least one speed-regulating pump, differential pressure regulation can be achieved as required to save energy in the combined cycle system. In addition, automatic hydraulic compensation is achieved by this regulation.

[0008] The flow rate of the medium (e.g., water / ethylene glycol mixture) circulating in the heat exchanger can be controlled so that the heat exchangers can each operate with an optimal degree of heat transfer.

[0009] According to one embodiment, the method further includes separately determining and adjusting the ΔT control valves in the intake air stream and the exhaust air stream with the largest valve opening degree, and adjusting the pressure increase by one or more speed adjustment pumps so that the power consumption of the system is reduced to the necessary minimum.

[0010] For example, when the ΔT value of the heat exchanger is too low, the flow rate of the medium can be reduced, and when the ΔT value of the heat exchanger is too high, the flow rate of the medium can be increased to optimize the heat transfer of the heat exchanger.

[0011] According to one embodiment of the present invention, the operating state of the air conditioning and ventilation system can be automatically determined based on the measured ΔT value, where the operating state includes a heating operating state or a cooling operating state. In this case, the ΔT target value of the determined operating state can be transmitted to the corresponding ΔT control valves of the heat exchangers in the intake air stream and the exhaust air stream, and the transmitted target value can be used to adjust the opening degree of each ΔT control valve. Thus, regardless of whether the air conditioning and ventilation system is in a heating operating state or a cooling operating state, the method can be automatically set to different operating states, and energy recovery can be automatically set for it.

[0012] In this case, the automatic determination of the operating state of the air-conditioning and ventilation system includes: determining, with reference to the ΔT value, whether each heat exchanger is in a neutral operating state, a heating operating state, or a cooling operating state; and determining which operating state the majority of the heat exchangers in the heat exchanger are in, where heat exchangers in the neutral operating state are not considered. The operating state of the air-conditioning and ventilation system can be set to the operating state of the majority of the heat exchangers in the heat exchanger. If the same number of heat exchangers should be in the heating operating state and the cooling operating state, the operating state corresponding to the heat exchanger with the largest amount of the ΔT value is set. Therefore, in any operating situation, even if, for example, the individual heat exchangers and individual components of the air-conditioning and ventilation system are not operating, the operating state can be determined, and the ΔT target value can be automatically adjusted according to the determined operating state.

[0013] In addition to energy recovery, the intake air to one or more intake air heat exchangers can be temperature-controlled by supplying heat or cold. In this case, the ΔT target value of the corresponding intake air heat exchanger can be appropriately adjusted to prevent the supplied energy from being supplied back to the exhaust gas heat exchanger through reflux.

[0014] Since the flow rate is regulated by a valve and the pressure increase is regulated by a valve controller to achieve the optimal degree of energy recovery, the system does not require additional hydraulic compensation.

[0015] According to some embodiments, it can further be determined whether the ΔT value of the heat exchanger is less than a fixed minimum value within a defined time interval, and if this is the case, the ΔT control valve of the heat exchanger can be completely closed because the heat exchanger does not contribute to energy recovery.

[0016] The closed ΔT control valve of the heat exchanger can be opened after a predetermined time interval, and after opening the ΔT control valve, it can be repeated to determine whether the ΔT value of the heat exchanger is less than a fixed minimum value within a defined time interval to determine whether the heat exchanger contributes to energy recovery during this period. In addition to being carried out at a predetermined time interval, this repetition can also be triggered, for example, by the fact that the energy recovery operation is briefly interrupted by a superior building automation and restarted when the indoor air technology device connected to the heat exchanger is turned on, or when the heat exchanger in the intake air flow or exhaust air flow does not have a sufficiently large ΔT value.

[0017] According to another embodiment, the present invention further provides a method for dehumidifying cold recovery (EKR) of intake air for an air conditioning and ventilation system, wherein each of a plurality of heat exchangers is arranged in the intake air flow, the intake air is cooled by a first dehumidifying heat exchanger to reduce the moisture content of the intake air, and the intake air is supplied with thermal energy again by a downstream heat exchanger. In this case, the two heat exchangers are connected by a common medium circuit, and wherein the medium flow through the dehumidifying heat exchanger and the downstream heat exchanger is adjusted such that the ΔT value between the flow temperature and the return temperature of the medium in each of these heat exchangers is adjusted to an EKR target value. Thus, in the EKR mode, the energy recovery through the EKR heat exchanger can be optimized by measuring the corresponding flow temperature and return temperature without measuring the intake air temperature, intake air flow, etc.

[0018] The present invention provides an apparatus for adjusting the operation of an intake air heat exchanger and an exhaust air heat exchanger of a combined cycle system of an air conditioning and ventilation system, a combined cycle system station, and a machine-readable storage medium containing instructions that, when executed in a processor of a controller of a combined cycle system of an air conditioning and ventilation system, are adapted to perform the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 An example of a combined cycle system in an air conditioning and ventilation system is shown, in which energy recovery can be performed according to an embodiment of the present invention.

[0020] Figure 2 An example of a combined cycle system in a variant having an intake air heat exchanger and an outlet air heat exchanger is shown.

[0021] Figure 3 An example of a combined cycle system in a variant having any number of intake air heat exchangers and exhaust gas heat exchangers is shown.

[0022] Figure 4 A schematic diagram of a control method for a corresponding ΔT control valve according to an embodiment of the present invention is shown,

[0023] Figure 5A and Figure 5B A functional diagram of a method according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] In the following detailed description, exemplary embodiments and variants of the present invention will be explained with reference to the drawings. This is only helpful for understanding the present invention and the present invention is naturally not limited to specific embodiments. Features of different embodiments can be combined with each other even if this is not specifically explained in individual cases.

[0025] Figure 1 shows a combined cycle system station 10 (KVS station) for an air-conditioning and ventilation system (not shown) for, for example, buildings, industrial plants, hospitals, etc. In Figure 1 the illustrated combined cycle system (KVS) 10, a medium (such as a water-ethylene glycol mixture) passes through one or more exhaust gas heat exchangers 11 and one or more intake air heat exchangers 12, respectively, in order to extract heat or cold from the exhaust gas and feed it to the intake air. It should be noted here that the exhaust gas heat exchanger and the intake air heat exchanger are designed as separate devices so that the corresponding intake air flow and exhaust gas flow can be spatially separated and the intake air can be prevented from being contaminated by bacteria or pollutants that may be contained in the exhaust gas. For temperature control and dehumidification of the exhaust gas, a cooler 13 and / or a reheater 14 can also be optionally provided, as Figure 1 shown. Two temperature sensors 15 are respectively provided at the exhaust gas heat exchanger 11 and the intake air heat exchanger 12, and these two temperature sensors measure the flow temperature and the return temperature of the medium. The temperature difference ΔT value is determined based on these measured temperatures.

[0026] In addition, an optional temperature sensor can be provided in the intake air flow, which measures the temperature of the intake air passing through the cooler 13 and the reheater 14. With the help of these measured temperatures, intake air temperature regulation with dehumidification cold recovery is achieved.

[0027] A heat / cold feed module 16 can be provided for temperature control of the medium.

[0028] During operation, the medium is pumped through one or several pumps 18 through the (multiple) exhaust gas heat exchangers 11 and the (multiple) intake air heat exchangers 12, and a pressure compensation vessel 17 is provided. The flow of the medium through the (multiple) exhaust gas heat exchangers 11 and the (multiple) intake air heat exchangers 12 is controlled by a ΔT control valve 19 according to the determined ΔT value, as will be explained in detail below with reference to some examples. In the exemplary embodiment shown here, the ΔT control valve 19 is designed as a pressure independent control valve (PICV) 19, but other types of control valves can also be used. Through a power control valve 20, heat transfer between the intake air heat exchanger and the exhaust gas heat exchanger can be centrally controlled during part-load operation.

[0029] Based on the ΔT value, the operating state (such as heating operation or cooling operation) can be preliminarily determined. According to the determined operating state, the ΔT target value of the ΔT control valves of the intake air heat exchanger 11 and the exhaust gas heat exchanger 12 can then be set.

[0030] Then, the operation of heat exchangers 13 and 14 for dehumidifying cold recovery of exhaust gas can be optimized according to an embodiment, whereby the temperature difference ΔT value between the flow temperature and the return temperature of these heat exchangers is also determined. Accordingly, the medium flow rate flowing through heat exchangers 13 and 14 can be set such that the corresponding ΔT value is adjusted to the EKR target value of the corresponding EKR heat exchanger. This adjustment of the medium flow rate can be achieved by adjusting the speed of the pump and / or by adjusting the opening of the ΔT control valve of the EKR heat exchanger.

[0031] According to an exemplary embodiment, during energy / heat recovery release (WRG release), the KVS is started in the last stored operating state. During initial operation or after a relatively long downtime, the neutral operating state (N) is set. Automatic operating state recognition for heating or cooling operation (H / K) is then carried out according to the ΔT values determined for each of the heat exchangers 11, 12 and operates according to the majority principle. For each heat exchanger, the operating state is determined with reference to the ΔT value, as specified in Table 1 below, and then it is calculated which operating state the majority of the heat exchangers in the heat exchanger are in. Heat exchangers not in the neutral (N) operating state do not have the right to vote. In the case of a 50 / 50 tie, the ΔT value with the most significant magnitude will win the operating state vote and determine whether the system should be in the H operation or the K operation.

[0032]

[0033] Table 1

[0034] If energy is supplied via the hot / cold feed module 16 during WRG operation, the task of the two control loops (one for heating operation and one for cooling operation) is to regulate the WRG demand to, for example, 75%. Only one of these control loops is active in each operating state (H / K) and acts on the supply of the corresponding heating or cooling capacity. The more energy is supplied, the closer the medium temperature at the inlet of the intake air heat exchanger becomes, so the intake air temperature approaches the desired value, whereby the WRG demand decreases again. In the absence of any supply, each intake ΔT control valve requires two ΔT target values (one target value for the heating operating state and one target value for the cooling operating state). Each feed requires an additional ΔT value respectively. Therefore, four ΔT target values (H; H2 / K; K2) are required for the H feed and the K feed. During feeding, the absolute ΔT target value of the intake air heat exchanger 12 is greater than the ΔT target value without feeding. This should prevent the supplied energy from being supplied back to the exhaust gas heat exchanger 11 via the return flow. To prevent the medium being heated or cooled from reaching the return end of the intake air heat exchanger 12 due to feeding and flowing towards the exhaust gas heat exchanger 11, whereby the supplied energy would be lost, the medium flow through the exhaust gas heat exchanger 12 is regulated such that by throttling the feed, the return temperature of the intake air heat exchanger 12 and the return temperature of the exhaust gas heat exchanger medium remain at a 5K difference in the correct direction (heating operation: Tintake medium < Texhaust medium; cooling operation: Tintake medium > Texhaust medium). The function of this control loop can be switched off.

[0035] To prevent any feed from inadvertently affecting the operating state recognition, it can be stipulated that the operating state (H / N / K) is only switched after a few minutes have elapsed after the cold feed or the hot feed.

[0036] As shown in Table 1 above, the operating states also include the operating state of dehumidifying cold recovery (EKR). In this case, the intake air is cooled by dehumidifying the heat exchanger 13 to reduce the moisture content of the intake air, whereby the water vapor contained in the intake air is condensed during cooling, and the thermal energy is supplied to the intake air again via the downstream heat exchanger 14, wherein the two heat exchangers 13, 14 are connected via a common medium circuit. Since EKR is a particularly energy-saving method for dehumidifying the intake air flow and pre-temperature control, in this example, the operation of EKR has priority over energy recovery.

[0037] In this case, the EKR demand acts as the post-heating demand. The EKRΔT control valve releases when the EKR demand is 10% and blocks again at 0% (separating the after-heater). Pump 18 regulates the pressure increase during EKR operation as well as during WRG operation. The target value of the pressure increase is limited upwards by the EKR demand and downwards by the widest opening of the EKR and ΔT control valves. During EKR operation, the widest opening of the ΔT control valve is maintained by continuously adjusting the pressure increase to, for example, 75%. The WRG demand has no effect on the target value of the pressure increase of the EKR.

[0038] When the return temperature of the intake air heat exchanger 12 in the KVS station is lower than the return temperature of the exhaust gas heat exchanger 11, the WRGΔT control valve will separate the exhaust gas heat exchanger 11. In this case, the release is withdrawn from the exhaust gas heat exchanger 11 and the exhaust gas heat exchanger 11 is completely closed. This state can be temporarily cancelled and rechecked periodically. This check is based on the automatic recognition of the operation of the intake air heat exchanger 11 and the exhaust gas heat exchanger 12 and is started immediately.

[0039] During the cooling operation, it can also be suitable for adiabatically cooling the exhaust gas flow. If the calculated wet-bulb temperature upstream of the humidifier is at least 2K lower than the measured exhaust gas temperature, it is suitable to release the exhaust gas humidifier for adiabatic cooling. For the dehumidification operation, it is considered that if the calculated wet-bulb temperature upstream of the humidifier is at least 2K lower than the measured exhaust gas temperature at that location, it is suitable to release the exhaust gas humidifier for adiabatic cooling when it is 2K lower than the return temperature to the exhaust gas heat exchanger 11 measured in the KVS station 10.

[0040] In addition, in Figure 1 the KVS station 10 shown, frost protection measures can be integrated. If the temperature of the flowing medium to the exhaust gas heat exchanger 11 does not exceed 2K below the dew point temperature of the exhaust gas, frosting can be prevented. This can be achieved by the frost protection valve 21. If the exhaust gas humidity and temperature measurement values for dew point calculation are not transmitted to the KVS station by the superior air conditioning or ventilation system or the central controller, 0 o °C can be assumed as the dew point temperature.

[0041] As a further optional supplement to the foregoing method, the operation of the intake air heat exchanger 11 and the exhaust gas heat exchanger 12 can be automatically detected. In this case, during WRG release, all ΔT control valves 19 first receive their release for ΔT control. If the ΔT value of the ΔT control valve 19 remains almost zero or even has a reverse sign within a certain time (e.g., ±2K), the relevant heat exchanger makes no contribution to the WRG or its use, and the corresponding indoor air technology device on the exhaust gas side or the intake air side probably does not function. Then the release is withdrawn from the ΔT control valve 19 so that it is completely closed.

[0042] For example, if one or more of the following conditions are met, this status can be temporarily cancelled and rechecked periodically by the ΔT control valve 19:

[0043] ● If the WRG release is briefly withdrawn and then granted again. In this case, the WRG can simply continue to operate through a bridged overrun (e.g., release pulse for 1 second, overrun for 2 seconds). This is a particularly simple way to perform a cyclic check to determine whether the heat exchangers each contribute to the WRG;

[0044] ● When the indoor air technology device is closed or opened;

[0045] ● When the exhaust gas humidifier for adiabatic cooling is opened or closed; if the WRG demand has changed since the last check (e.g., changed by at least ±5%) (release all ΔT control valves 19 and re-evaluate).

[0046] ● When the WRG demand >= 95% (release all ΔT control valves and re-evaluate).

[0047] ● When there is no heat exchanger in the incoming air stream with an absolute (ΔT) > 2K temperature difference in the correct direction. In this case, all ΔT control valves of the incoming air heat exchangers can be released and re-evaluated;

[0048] ● When there is no heat exchanger in the exhaust gas stream with an absolute (ΔT) > 2K temperature difference in the correct direction. In this case, all ΔT control valves of the exhaust gas heat exchangers can be released and re-evaluated;

[0049] All options listed above can be parameterized and selected or deselected. If no option is selected, the ΔT control valve receives the WRG release without further restrictions.

[0050] If a humidifier for adiabatic cooling should be provided, the air conditioning or ventilation system can release the humidifier for cooling (at an appropriate time before the test) if appropriate. The operating state automatic recognition device takes into account the cooling potential provided thereby during the test.

[0051] Typically, for example, a digital signal for WRG release, an optional analog WRG demand with external temperature control or an external temperature target value specified by the KVS station 10 for temperature control, an optional analog EKR demand with external temperature control, an analog temperature target value that can be received at the same input as the WRG demand and is optionally temperature-regulated by the KVS station 10, an optional analog value of the exhaust gas temperature for determining the dew point and / or an optional analog value of the exhaust gas humidity can be received at the KVS station 10 as input variables for the method according to an embodiment. In particular, the temperature value and humidity value required at the KVS station 10 can be measured using sensors.

[0052] Figure 2 An example of the operation of the KVS station 10 with an intake air heat exchanger 12 and an exhaust gas heat exchanger 11 is shown. Since it is not appropriate to separate one of the two heat exchangers 11, 12 by closing the ΔT control valve in this case, in this embodiment, the previously described ΔT control valve can also be omitted, and the control of the medium flow rate through the heat exchangers 11, 12 can be achieved by adjusting the speed of the pump 18. As described above, the ΔT target values for different operating states are stored in the memory 22.

[0053] For example, in this embodiment, energy recovery can be performed such that after the KVS station is released, one of the pumps in the pump 18 starts from 10% of the WRG demand (closing hysteresis -10%). Between 0% and 10% WRG demand, the WRG power valve 20 opens from 0% to 100%. Through the WRG demand, the differential pressure target value of the pump is linearly interpolated between the minimum and maximum values. The differential pressure is limited upward (throttled) by a control loop that controls the ΔT between the flow and return of the exhaust gas heat exchanger 11. Therefore, the pump speed is optimized as needed, which reduces the average energy demand.

[0054] Figure 3 An example of the operation of the KVS station 10 with any number of intake air heat exchangers 12 and exhaust gas heat exchangers 11 is shown, where compared with Figure 2 the embodiment shown, the medium flow rate through the respective heat exchangers 11, 12 is adjusted by controlling the opening degree of the ΔT control valve 19. During energy recovery operation, as soon as the relevant air conditioning and ventilation system is in operation, the ΔT control valve 19 receives the release of the control operation. Each ΔT target value is transmitted to each ΔT control valve 19 in the KVS station 10. The ΔT target values for the heating case and the cooling case are stored in the memory 22 of the KVS station 10. The controller of the KVS station device automatically determines the heating case and the cooling case by comparing the flow temperature and the return temperature. In the heating case, the ΔT target value of the ΔT control valve 19 in the exhaust gas is positive, while the ΔT target value of the ΔT control valve representing the WRG power valve in the KVS station 10 is negative.

[0055] During the planning process, the ΔT target values for the heating and cooling cases can be calculated for each ΔT control valve 19 and predefined as fixed values. The same applies to the minimum and nominal flow rates of each valve, which can be individually configured during the commissioning of each plant. Within these limits, the respective ΔT control valve 19 can operate in an independent continuous mode to maintain the temperature difference ΔT at its target value.

[0056] After the KVS station is released, one of the pumps 18 starts from a WRG demand of, for example, 10% (switch-on hysteresis -5%). Between 0% and 10% WRG demand, the WRG power valve opens from 0% to 100%. Through the WRG demand, the differential pressure target value of the pump is linearly interpolated between the minimum and maximum values, as Figure 4 shown:

[0057] y Xx Position confirmation of the respective ΔT control valve 19,

[0058] X Fmax Maximum position confirmation of all ΔT control valves as a control parameter of the main controller;

[0059] W F Target value of the main controller (in bar);

[0060] y F Control signal of the main controller;

[0061] P Min Lower limit of the scaling of the main controller signal (in bar);

[0062] P Max Upper limit of the scaling of the main controller signal (in bar);

[0063] W N Target value of the auxiliary controller (in bar);

[0064] x N Measured differential pressure value (in bar) as a control variable of the auxiliary controller;

[0065] y N Control signal of the auxiliary controller.

[0066] By limiting the maximum valve opening of the ΔT control valve 19 (the maximum value in y zmax and y amax = x Fmax downward to, for example, 75% of the control loop upward limit (throttling) pressure difference. Thus, the pump speed is optimized as needed, which reduces the average energy demand.

[0067] When there is a thermal imbalance between the intake air heat exchanger and the exhaust gas heat exchanger, at least one of the ΔT control valves 19 for the intake air and the exhaust gas opens in the 100% direction. To facilitate automatic hydraulic compensation in this scenario and thus optimize WRG power, the air side with the widest valve opening requires more medium flow than the opposite air side. This is achieved by an additional control loop that is responsible for limiting the maximum valve opening of the intake air heat exchanger and the exhaust gas heat exchanger to, for example, 85% open. The control signal of this control loop acts on the opening of the anti-frost valve 21 when the relevant valve is on the exhaust gas side and acts on the bypass through the WRG power valve 20 when the WRG power valve 20 is on the exhaust gas side. Here, the anti-frost valve has priority. When the anti-frost valve 21 is open, the bypass of the WRG power valve 20 remains closed. It is not possible for the bypass valve of the WRG power valve 20 and the anti-frost valve 21 to be open simultaneously.

[0068] According to one embodiment, the software for implementing the foregoing method can be constructed in a layer model, where in the first stage, hydraulic control is performed, whereby, as described above, through ΔT management and optionally by supplying heat and / or cold to the medium, energy-saving pump operation and efficient use of the supplied energy are achieved. In the second stage, the air temperature is regulated, which involves regulating the exhaust gas and / or the intake air, and optionally adiabatic cooling and / or dehumidification cold recovery. In the third stage, then optimization functions are implemented, which, for example, by calculating the starting value and the limiting value of the control signal, achieve more rapid stabilization of the control loop.

[0069] Figure 5A and Figure 5B A simplified functional diagram of a method according to one embodiment is shown. As described above, it can be seen that the Δ control valve is opened to an opening degree of at least 75% (for example (S1)), and the pump speed is adjusted accordingly to achieve the target value of the differential pressure (S2). By comparing the exhaust gas temperature and the intake air temperature with the corresponding target values (S3), a WRG demand can be generated (S4), which can be received as an analog signal (for example, a percentage), and can be taken into account during pressure regulation by the speed-controlled pump.

[0070] In addition, automatic compensation (S5) is also performed, where the flow through the heat exchanger can be compensated by the power valve 20. Anti-frost control (S6) prevents any frost formation by controlling the opening of the anti-frost valve 21.

[0071] Finally, the external heat and cold supply (S7, S8) can be considered, where the WRG demand is adjusted accordingly for efficient use of the supplied energy.

Claims

1. A method for controlling the operation of an intake air heat exchanger and an exhaust gas heat exchanger of a combined cycle system of an air conditioning and ventilation system, comprising: At least one inlet air flow and / or at least one exhaust air flow of the air conditioning and ventilation system is supplied to one or more heat exchangers through which the medium flows: Measuring the temperature difference ΔT between the flow temperature and the return temperature of the medium in each heat exchanger; The medium flow rate passing through the relevant heat exchanger is set so that the ΔT value of the relevant heat exchanger is adjusted to the target value.

2. The method of claim 1, wherein: The setting of the medium flow through the heat exchanger is accomplished by adjusting the rotational speed of at least one speed regulating pump.

3. The method according to claim 1 or 2, wherein: The setting of the medium flow through the heat exchangers is accomplished by adjusting the opening degree of the ΔT control valve of each heat exchanger.

4. The method according to any one of claims 1 to 3, further comprising: Determine and adjust the ΔT control valves with maximum valve opening in the intake and exhaust lines, respectively, The pressure increase is regulated by one or more speed-regulated pumps so that the power consumption of the system is reduced to the necessary minimum.

5. The method according to any one of claims 1 to 4, further comprising: In the case where the ΔT value of the heat exchanger is too low compared to the target value, reducing the opening degree of the relevant ΔT control valve to reduce the flow rate of the medium passing through the heat exchanger, and In the case where the ΔT value of the heat exchanger is too high compared to the target value, the opening degree of the relevant ΔT control valve is increased to increase the flow rate of the medium passing through the heat exchanger.

6. The method according to any one of claims 1 to 5, further comprising: automatically determining an operating state of the air conditioning and ventilation system based on the measured ΔT value, wherein the operating state includes a heating operating state or a cooling operating state, transmitting the determined target values ​​of the operating state to the corresponding ΔT control valves of the heat exchangers in the intake flow and the exhaust flow, The transmitted target value is used to implement regulation of the opening degree of each ΔT control valve.

7. The method of claim 6, wherein automatically determining the operating status of the air conditioning and ventilation system comprises: determining whether each heat exchanger is in a neutral operating state, a heating operating state, or a cooling operating state with reference to the ΔT value; as well as determining in which operating state the majority of the heat exchangers are in, wherein heat exchangers in a neutral operating state are not taken into account, and wherein the operating state of the air conditioning and ventilation system is set to the operating state of the majority of the heat exchangers, If the same number of heat exchangers should be in the heating operation state and the cooling operation state, the operation state corresponding to the heat exchanger having the largest number of ΔT values ​​is set.

8. The method according to any one of claims 1 to 7, further comprising: Heat or cooling is supplied to one or more heat exchangers in the intake air stream to control the temperature of the intake air.

9. The method of claim 8, further comprising: A target value of a ΔT value of one or more heat exchangers in the intake air flow supplied with a heating medium or a cooling medium is adjusted to prevent the supplied energy from being supplied to the exhaust gas heat exchanger by a backflow.

10. The method according to any one of claims 1 to 9, further comprising: Determine whether the ΔT value of the heat exchanger is less than a fixed minimum value within a defined time interval, and If this is the case, the ΔT control valve of the heat exchanger is completely closed.

11. The method of claim 10, comprising: opening a closed ΔT control valve of the heat exchanger after a predetermined time interval; It is repeatedly determined within defined time intervals whether the ΔT value of the heat exchanger is less than a fixed minimum value and, if this is the case, the complete closing of the ΔT control valve of the heat exchanger is repeated.

12. The method of any one of claims 1 to 11, wherein: A plurality of heat exchangers are each arranged in the inlet air flow, The intake air is cooled by a first dehumidification heat exchanger to reduce the moisture content of the intake air, and The intake air is supplied with heat energy again through the downstream heat exchanger. Wherein, two heat exchangers are connected by a common medium loop, and wherein the medium flow through the dehumidification heat exchanger and the downstream heat exchanger is regulated so that the ΔT value between the flow temperature and the return temperature of the medium in each of these heat exchangers is adjusted to the EKR target value.

13. A device for regulating the operation of an intake air heat exchanger and an exhaust gas heat exchanger of a combined cycle system of an air conditioning and ventilation system, the device comprising: a sensor for measuring a temperature difference ΔT between a flow temperature and a return temperature of a medium in each of the intake heat exchanger and the exhaust heat exchanger; A controller is used to set the medium flow rate through the relevant heat exchanger so that the ΔT value of the relevant heat exchanger is adjusted to a target value, wherein the setting of the medium flow rate includes adjusting the speed of at least one pump and / or adjusting the opening degree of the ΔT control valve of each of the heat exchangers.

14. A combined cycle system station for an air conditioning and ventilation system, the combined cycle system station comprising: one or more heat exchangers in at least one intake air stream of the air conditioning or ventilation system and one or more heat exchangers in at least one exhaust air stream of the air conditioning and ventilation system, wherein the medium flows through the intake air heat exchanger and the exhaust air heat exchanger; A sensor for measuring a temperature difference ΔT between a flow temperature and a return temperature of a medium in each of the heat exchangers; A controller is used to set the medium flow rate through the relevant heat exchanger so that the ΔT value of the relevant heat exchanger is adjusted to a target value, wherein the setting of the medium flow rate includes adjusting the speed of at least one pump and / or adjusting the opening degree of the ΔT control valve of each of the heat exchangers.

15. A machine-readable storage medium, comprising instructions, which are suitable for executing the method according to any one of claims 1 to 12 when the instructions are executed in a processor of a controller of a combined cycle system of an air conditioning and ventilation system.

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