WO2006000262A1

WO2006000262A1 - Method and device for determining the state of a heat transfer device

Info

Publication number: WO2006000262A1
Application number: PCT/EP2005/002836
Authority: WO
Inventors: Ronald Hepper; Ralf Niebe
Original assignee: Wiessner Gmbh
Priority date: 2004-06-28
Filing date: 2005-03-17
Publication date: 2006-01-05
Also published as: DE102004031276A1

Abstract

The invention relates to a method and device for determining the state of a heat transfer device through which at least two heat media flow and wherein heat is transferred between the at least two heat media in a heat transfer process. For this purpose, a) at least one physical measuring variable of at least one of the heat media is measured during heat transfer, and b) a value of at least one state variable depending on the measuring value(s) and characterizing the state of the heat transfer device is determined based on the measured values or measuring signals of the measured variable(s).

Description

METHOD AND DEVICE FOR DETERMINING A STATE OF A HEAT TRANSFER DEVICE

description

The invention relates to a method and a device for determining a state of a heat transfer device.

Heat transfer devices, also called heat exchangers or Wärmetau shear, are known in various embodiments and in a variety of applications. In a heat transfer device, heat is transferred from a gaseous or liquid heat medium flowing through the heat transfer device to another gaseous or fluid heat medium also flowing through the heat transfer device. For heat transfer, all Wärmerans¬ port mechanisms, ie heat conduction, heat convection and / or Wärme¬ radiation are used, wherein in the convection in addition a phase transformation or state of aggregation state by evaporation or condensation can be used.

In practice, as heat transfer devices mainly three types of heat exchangers in use, namely so-called Rekuperato¬ Ren or recuperative heat exchangers, regenerators or regenerative heat exchangers and direct contact heat exchangers. Regenerative heat exchangers are generally used for discontinuous operation, while recuperators are predominantly used for continuous operation.

In recuperators, a partition wall or heat transfer surface is arranged between the two streams of the heat media, so that a heat transfer takes place through the heat transfer surface. Reproducible heat exchangers are mainly tube heat exchangers or plate heat exchangers. Heat exchangers used. In a tube heat exchanger, a plurality of tubes are usually arranged parallel to each other and one of the Wärme¬ media is passed through the interior of the tubes. By contrast, the other heat medium flows along the outside of the tubes. In a plate heat exchanger, individual plates are arranged parallel to one another and one of the heat media flows through a part of the intermediate spaces between the plates and the other heat medium through the other part of the intermediate spaces between the plates. The materials used for the recuperative heat exchangers are materials which are corrosion-resistant and have smooth surfaces, for example glass, plastic-coated metals and stainless steels.

In the case of a cross-flow heat exchanger, the flows of the two heat mediums are crossed or orthogonal to one another, in the case of a DC heat exchanger in the same direction and in the case of a countercurrent heat exchanger in opposite directions.

In regenerative heat transfer in regenerators, storage masses are used which are alternately brought into contact with the heat-emitting and the heat-absorbing medium, for example the exhaust air flow and the supply air flow. Usually, the storage mass is continuously rotated, for example accommodated in a cylindrical rotor which is driven by a motor. The two fluid heat media flow through the storage mass of the regenerator, usually in countercurrent, and are conducted in separate channels before and after the heat exchanger.

One of the most important applications of heat transfer equipment is heat recovery, especially in the industrial sector. In this case, residual heat or waste heat or heat recovery in one of a, in particular industrial, process effluent heat medium, for example Exhaust or exhaust air, for own use in the process or for Fremdnut¬ tion in other processes or for heating purposes at least partially recovered. The most common use in the process is the preheating of the other heat medium, for example, the supply air, which is then used in the process.

In the heat transfer and heat recovery of exhaust air always the presence of water or moisture in the air is to be noted, which can lead to the condensation of water in the heat exchanger and for the so-called exchange number of the heat recovery zugerei¬ conditions. The exchange number defines in heat recovery the intensity or the efficiency or the efficiency of the transfer of heat and moisture from the one medium, eg. B. exhaust, on the other medium z. B. supply air.

In the case of heat recovery from exhaust air, the three physical variables temperature, enthalpy and humidity of the supply air on the one hand and the air on the other hand are of importance for the transferred heat flow. One differentiates between the exchange numbers for the enthalpy, for the temperature and for the humidity. The exchange number for the enthalpy transmission corresponds to the quotient of the difference between the enthalpy of the supply air after the heat exchanger and the enthalpy of the supply air upstream of the heat exchanger on the one hand and the difference between the enthalpy of the exhaust air upstream of the heat exchanger and the enthalpy of the exhaust air downstream of the heat exchanger on the other hand. The exchange rate for the temperature transfer, ie the temperature efficiency, is defined as the quotient of the difference between the temperature of the supply air after the heat exchanger and the temperature of the supply air upstream of the heat exchanger on the one hand and the difference of the temperature of the exhaust air upstream of the heat exchanger and the temperature of the exhaust air to the heat exchanger on the other. Accordingly, the exchange number for the moisture transfer is defined as the quotient of the difference between the moisture charge of the supply air after the heat exchanger and the moisture loading of the supply air upstream of the heat exchanger on the one hand and the difference in the moisture content. charge the exhaust air before the heat exchanger and the moisture content of the exhaust air to the heat exchanger on the other.

The heat exchange between the heat media in the heat transfer device is the more efficient the closer the exchange number to 1. With negligible replacement, the exchange numbers go to 0 and with ideal replacement against 1. The size of the exchange numbers depends on the type of heat exchanger and also on the flow control.

The exchange rates are set once in the design of heat exchangers to optimize their efficiency and heat transfer behavior. However, a once designed heat exchanger is then no longer checked or monitored during operation with regard to its heat transfer behavior or its current exchange number. As a result, in the case of a deterioration in the efficiency of a heat exchanger in a heat recovery system, considerable energy losses can occur. Such a deterioration of the efficiency can be achieved, for example, by soiling or clogging in the heat exchanger or a pipe or a break or crack in a glass tube of a pipe heat exchanger or by aging or even material wear or corrosion

However, this problem is either not perceived at all or accepted in the practice of industrial heat recovery.

The invention has for its object to admit a method of a device for determining a state of a heat transfer device an¬.

This object is achieved according to the invention with the features of claim 1. and of claim 29.

The invention is based on the consideration, the state and / or the heat transfer behavior of a heat exchanger during operation by measuring selected measured variables of the heat media involved in the heat transfer and evaluation of the measured values or measurement signals obtained and thus the user values of parameters for the state, in particular the heat transfer behavior of the Wärmeübertragers during operation or during the Wärmeübertragungs¬ process to provide.

In the prior art, a set or designed heat transfer characteristic of a heat exchanger during operation can no longer be ascertained or checked, and thus the actual heat transfer characteristic of the desired characteristic or the actual state of the heat exchanger can be raised from its desired state without this being quantitatively analyzed.

By contrast, the invention enables for the first time a quantitative assessment or analysis of the actual state or the actual characteristic of a heat exchanger during its use or operation, for example in heat recovery.

The user can now directly "online" get the current values of the characteristic values on a display unit, eg his process control system or process control system (visualization) Furthermore, the determined values or characteristics of the characteristic quantities or the primary measured values and measurement signals over predetermined, longer Periods are stored ("histories") and with these stored progressions also in Nach¬ into or evaluations or analyzes of the heat transfer systems are made. With these measures, continuous monitoring and monitoring of the heat transfer or recovery plant during its entire service life is possible, in particular in the context of process control tasks or in an existing process control system for a complete installation in which the heat transfer or heat transfer takes place recovery plant is integrated as a component. Finally, it is also possible with the help of the invention, the heat transfer behavior of a Heat exchanger even in operation (again) to optimize by ver¬ change of manipulated variable (s) such that the parameter (s) is again in a ge desired range or lie.

Advantageous embodiments and further developments as well as applications of the method and the device emerge from the claims dependent respectively from claims 1 and 29.

The invention will be explained below with reference to exemplary embodiments. Reference is made to the drawing, in which a heat recovery system in a process air system in a schematic diagram, Figure 2, the calculation of physical quantities of an air flow ge according to FIG 1 from its measured variables temperature and relative humidity in a graph, FIG FIG. 4 shows the calculation of a compensated volumetric flow or mass flow of the air flows according to FIG. 1 in a diagram, FIG. 5 the calculation of the heat quantity efficiency of a heat exchanger 1 in a diagram, the calculation of the transmitted heat output and the amount of heat transferred a heat exchanger according to FIG 1 in a diagram, the calculation of the heat quantity efficiency ei¬ nes heat exchanger according to FIG 1 in a graph, FIG 7, the calculation of Temperature of in the heat Ausc 8 shows the calculation of the mass flow of condensate arising in the heat exchanger according to FIG. 1 in a diagram, FIG. 9 shows the detection of a glass tube break in the heat exchanger according to FIG. 1 by evaluating moisture loadings in a diagram and FIG 10 shows the detection of a glass tube break in the heat exchanger according to FIG. 1 by evaluating mass flows in a diagram

are each shown schematically. Corresponding parts and sizes are provided in FIGS. 1 to 10 with the same reference numerals.

FIG. 1 shows a process air system which supplies supply air ZL to a process area 2 via an air inlet inlet 3 and removes exhaust air ABL from the process area 2 via an exhaust air outlet 4.

A Zuluftventilator 5 sucks outdoor air AL from an outdoor space, usually atmospheric air or hall air, on, which flows at an input 21 in a heat exchanger 10 and the heat exchanger 10 flows through, and at an output 22 as supply air ZL flows again to Zuluftventila- gate 5. In at least one heating device 31, the supply air ZL, after the supply air fan 5 and upstream of the supply air inlet 3, is heated to a predetermined temperature, which is desired for conditioning or supplying the process zone 2 with process air.

The process area 2 can be, for example, a paper or pulp mill and the supply air ZL can be used to dry the paper or pulp webs in the machine. In this case normally be Lufttempe¬ temperatures of the supply air ZL of 110 ⁰ C to 120 ⁰ C. The invention is not limited to this application.

At the same time as supplying the supply air ZL into the process area 2, the exhaust air ABL is drawn off from the process area 2 via the exhaust air outlet 4 by means of an exhaust air fan 6 and introduced into the heat exchanger 10 via a further inlet 23 of the heat exchanger 10, passed through this and at a another output 24 of the heat exchanger 10 as exhaust air FL discharged again to the exhaust fan 6 out. The exhaust air ABL still contains a considerable residual heat. In a paper machine, the exhaust air ABL typically has temperatures of between 70 ⁰ C and 90 ° C.

The waste heat contained in the exhaust air ABL is now at least partially recovered in the heat exchanger 10 by air for preheating or heating the outside air AL or for providing preheated Zu¬ ZL, which is then brought by the heater 31 to the final temperature, is used. For example, the outside air AL can be brought from an outside temperature of typically - 15 ° C to + 30 ° C to a pre-temperature of + 50 ° C to + 70 ° C, which then as supply air ZL at the exit from the heat exchanger 10th having.

The heat exchanger 10 is formed for example as a cross-flow tube heat exchanger, in the vertical glass tubes of the exhaust air flow ABL is guided vertically from bottom to top and outside of the glass tubes along the outside air flow AL is guided horizontally. In this version, condensate of the exhaust air ABL can flow off more easily downwards. However, other types and designs of heat exchangers are usable.

In addition, to increase the energy efficiency, further residual heat of the exiting from the heat exchanger 10, usually still 60 ⁰ C to 65 ⁰ C warm exhaust air FL in another heat recovery 30, spielsweise an air / water / heat exchanger with a water circuit 32 with a pump to be withdrawn. This heat of the exhaust air FL recovered in the heat recovery unit 30 can be used, for example, for heating and / or for air conditioning of the hall or building air.

The heat exchanger 10 are now assigned four sensor devices 11 to 14 zuge¬. The sensor device 11 is connected upstream of the inlet 21 of the heat exchanger 10 into the flow path of the outside air AL and measures measured variables of the outside air AL. The sensor device 12 is the output 22nd arranged downstream of the heat exchanger 10 in the flow path of the supply air ZL and measures measured variables of the supply air ZL. The sensor device 13 is connected upstream of the inlet 23 of the heat exchanger 10 into the flow path of the exhaust air ABL and measures measured variables of the exhaust air ABL. Finally, the sensor device 14 is connected behind the output 24 of the heat exchanger 10 into the flow path of the exhaust air FL and measures measured variables of the exhaust air FL.

The water circuit 32 of the optional heat recovery device 30 is also associated with a sensor device 16 for measuring measured variables of the water. Furthermore, the optional heat recovery device 30 in the flow path of the exhaust air FL downstream of a further sensor device 17 for measuring measured variables of the exhaust air FL after flowing through the heat exchanger 30th

The sensor devices 11 to 14 and 16 may have analog or digital sensors. In the case of analog sensors, their sensor or measuring signals are preferably digitized and further processed in the form of digital signals. Basically, of course, an analog signal processing of the analog measurement signals is possible. With digital sensors, these provide equally digital measuring signals or measured values at their outputs.

The, preferably digital, outputs of the sensor devices 11 to 14 and 16 and 17 are each connected to inputs of an evaluation device (or: evaluation unit) 7. The evaluation device 7 may be integrated with one or more sensor devices 11 to 14 in one unit or operated as a separate structural unit and / or self-sufficient.

The evaluation device 7 evaluates the measured values or measurement signals obtained from the sensor devices 11 to 14 and determines therefrom physical quantities, at least physical parameters for the current heat transfer behavior and / or the state of the heat exchanger 10. The evaluation device 7 also evaluates the Measured values or measuring signals of the sensors For evaluation, the evaluation device 7 generally comprises at least one digital signal processor or microprocessor and associated memory for storing determined data and stored control and computation programs, as well as if necessary from value tables.

The evaluation results, ie the determined digital, in particular binary, values of the characteristic quantities, are transmitted by the evaluation device 7 via a data bus or a bus interface to a higher-level process control system 8. Standard bus technology such as Ethernet (TCP / IP) or Profibus can be used here. Furthermore, connections via line networks such as the Internet or telephone connections and / or modem and / or also wireless connections, for example via radio, mobile radio and / or satellite are possible. Of course, an analog signal processing and / or transmission of the measurement signals is also possible as an alternative.

The process control system 8 is provided only for the heat recovery system or for the entire process air system or else for the entire process, here for example the paper or cellulose production process in the paper or cellulose machine.

On a display device (or display unit) 9 of the process control system 8 and / or in or in the evaluation device 7, generally a graphic screen (display), for example a computer monitor, the values obtained by the evaluation device 7 are Kenn¬ sizes of the heat exchanger 10 and possibly the heat recovery 30 at least partially visualized or graphed, in particular in the form of numbers behind associated identifiers or physical symbols or in the form of curves, diagrams or similar known per se display modes. The user thus receives on the display device 9 continuously information about important parameters of the heat recovery tätf¬ fenden part of his system and can assess the condition of the heat exchanger 10 and possibly the heat recovery 30 and possibly optimize or correct. For the plant operator or user, the heat recovery system becomes transparent and plant availability is increased, analyzes of system economics can be made, decisions on energy optimization can be supported, and on-demand maintenance can be facilitated. In process control systems, know-how about heat recovery systems can be made available and integrated into overall concepts. Heat recovery systems themselves are upgraded with the intelligent evaluation

The sensor devices 11 to 14 for the heat exchanger 10 preferably comprise individual sensors for measuring the temperature t, the relative humidity φ and the volume flow or the pressure, in particular differential pressure, in particular dynamic pressure, of the associated air flow. Here, proven sensor technology of temperature, humidity, Volumen¬ flow and pressure measurement can be used.

For temperature measurement, for example, resistance temperature sensors can be used. For direct flow measurement, flowmeters such as ultrasonic, eddy frequency induction or anemometer flow sensors, back pressure or flow rate gauges can be used.

When using dynamic pressure measuring devices for measuring volumetric flows, in particular of a gaseous heating medium such as air, it is additionally possible to provide a self-cleaning device or function. In this case, via time-controlled valves, in particular solenoid valves, compressed air is blown through the dynamic pressure device, wherein preferably the pressure sensor is switched off and the measured value is fixed. For the pressure measurement or differential pressure measurement piezoelectric, inductive and / or mechanical sensors, membrane or spring pressure sensors can be used.

For measuring the relative humidity, for example, capacitive humidity sensors are used. However, instead of or in addition to the relative humidity, it is also possible to measure the absolute humidity or moisture loading x, for example directly by means of a LiCl moisture sensor, the conversion temperature of which depends on the absolute humidity, or indirectly by means of a dew point temperature sensor, for example a dew point mirror.

The water content of the air in the not yet saturated state essentially comprises water vapor (or: moisture, proportion of the water in the gaseous state) and in the supersaturated state additionally also entrained or floating water droplets (or: water in liquid form). At saturation or the associated saturation pressure, at a constant temperature equilibrium prevails between a liquid and its vapor in a predetermined arbitrary volume.

The absolute humidity or the absolute water vapor content or the moisture charge x corresponds to the quotient of the mass of the water vapor (vapor mass) contained in the air, measured for example in grams (g), and the mass of the dry air (dry air mass), usually expressed in kg, both masses being determined in the same gas volume, for example one cubic meter (1 m ³ ), at the same temperature and at the same pressure. The absolute vapor content or the moisture loading X is therefore a dimensionless quantity.

The relative water vapor content or the relative humidity φ is based on the saturation state and is defined as the quotient of the partial density or concentration of the water vapor at the predetermined temperature, for example measured in g / m ³ , and the saturation partial density of the water. steam which, upon reaching the saturation partial pressure of the water, sets or would adjust at the same temperature and is also measured in g / m ³ . The relative humidity also corresponds to the quotient of the current steam partial pressure and the saturation vapor partial pressure. The relative humidity is dimensionless and is usually given in percent (%), whereby in the subsatured state the relative humidity is below 100% and in the saturated state is 100%. With a higher temperature, the relative humidity decreases while the absolute humidity remains the same.

From the physical measured variables temperature, humidity (rel.) And volume flow / pressure measured by the sensor devices 11 to 14, a multiplicity of further physical variables of the heat recovery system, dependent on these measured variables, can be numerically calculated by the evaluation device 7 with the heat exchanger 10, for example, with stored analytical functions, equations, formulas or with fit functions or interpolation, or based on given value tables or characteristic curves or diagrams.

FIG. 2 shows in a diagram how different physical quantities are determined from the measured variables temperature t and relative humidity φ of each individual air stream with associated water content on the basis of relationships based on the Mollier diagram (or: hx diagram) or shown therein Such as • the moisture load (= absolute water content) x, • the density p, • the enthalpy (energy content) h and • the dew point t _t , can be calculated or determined.

In the Mollier diagram, the enthalpy h of the moist gas, usually humid air, is plotted over its moisture loading x (therefore: hx diagram), whereby on two orthogonal axes of the diagram on the abscissa the moisture loading x and on the ordinate the temperature t can be read. Isotherms are drawn from the corresponding temperature values on the ordinate as straight lines with an incline increasing with the temperature. Furthermore, the Mollier diagram contains isenthalps, which are parallel right-angled slopes with the slope of negative enthalpy of vaporization, and also convexly curved parameter curves of equal relative humidity φ, where the saturation curve is farthest down for φ = 100% and above that saturation curve Curves for φ <100%, ie the area of subsaturation and below the area of supersaturation or fog area.

The relationships shown graphically in the Mollier diagram are indicated below in the form of the corresponding equations or formulas.

Predefined or predefinable constants or constant system variables: System pressure: p _sys = const. Heat capacity air: c _pl = const. Heat of evaporation water; r = const. Heat capacity water vapor: c _pd = const.

Saturation pressure water vapor: p _{s (t)} is determined from temperature t according to stored table (with interpolation)

absolute humidity: x = 622 * ^{Ψ Ps {t)}

Enthalpy: h = c _≠ * t + x * (r + c _pd * t)

Partial pressure steam: p _D = ^^ _{+ χ} * p _sys 0.6222 partial air pressure: Pi = 0.6222 + x ^' P ₁ sys

Density: p = 0.00348 * S ^i. + 0.00217 * ^ A. tt

sys A ⁽ O ⁼ 622 dew point temperature: ^■ + φ φ = 100% (saturation) x with p _s , _t) in table => t _t

With the four temperature values t _{AL of} the sensor device 11, t _{ZL of} the sensor device 12, t _{ABL of} the sensor device 13 and t _{FL of} the sensor device 14, the evaluation device 7 now uses the evaluation device 7 as the first characteristic for the heat transfer in the heat exchanger 10 Current temperature efficiency (or: thermal efficiency, temperature exchange rate) η _{th of} the heat exchanger 10 as a quotient of the difference t _ZL - t _AL and the difference t _ABL - t _FL determined and transmitted to the process control system 8 for display on the display device 9.

FIG. 4 shows how an uncompensated volume flow of the medium with the predetermined parameters of the flow cross-sectional area A and the proportionality constant k of the sensor device (of the measuring element) first of all is measured from the differential pressure measured in the corresponding streaming heat medium by one of the sensor devices 11 to 14 or 16 and 17. be¬ is calculated and then densely compensated with the determined according to FIG 3 density p of Medi¬ this volume flow and also a corre sponding densely compensated mass flow is determined.

The compensated volume flows or mass flows of the media, for example AL, ZL, ABL, FL, according to FIG. 1, are now advantageously generated by the evaluation device 7 in order to calculate further indications to be displayed on the display device 9 Characteristics of the heat exchanger 10 used and can also be displayed on the display device 9 itself.

Thus, according to FIG. 5, the current heat quantity efficiency η _{Q of} the heat exchanger 10 is calculated from the four enthalpies h _{AL of} the outside air AL, h _{ZL of} the supply air ZL, h _{ABL of} the exhaust air ABL and h _{FL of} the outgoing air FL according to FIG 1 and the mass flow determined according to FIG. 4

mzL of the supply air ZL and TTIFL of the exhaust air FL.

6 shows the calculation of the exhaust air ABL on the outside air AL

transferred heat output Q and by numerical Sumtnation or

Integration over the heat output Q over the time obtained transmitted heat energy Q of the heat exchanger 10th

Due to the cooling of the exhaust air ABL in the heat exchanger 10 Konden¬ sat arise. According to predetermined relationships specific to the respective heat exchange process, the condensate temperature of the condensate produced in the heat exchanger according to FIG. 1 can now be determined from the measured values for the temperature and the relative humidity and with the aid of the hx diagram. For this purpose, the tau temperature t _t is preferably used simply as the condensate temperature.

8 shows the calculation of the mass flow of condensate arising in the heat exchanger according to FIG. 1 or the amount of condensate to be removed as the difference between the mass flow of the exhaust air ABL at the inlet 23 of the heat exchanger 10 and the mass flow of the exhaust air FL at the outlet 24 of the heat exchanger 10.

FIGS. 9 and 10 now show embodiments in which a glass tube break in a glass tube heat exchanger 10 is detected by the evaluation device 7 and can be displayed on the display device 9. It will exploited that a glass tube break leads to an exit of exhaust air ABL o- contained therein water vapor, which can be detected by measurement.

In the case of a heat exchanger 10 arranged on the pressure side of the exhaust air fan, the determined absolute moisture loadings x _{AL of} the outside air AL and x _{ZL of} the supply air FL are preferably compared or balanced with a formula in order to prevent a breakage or crack of the glass tube (n ) to recognize.

In a heat exchanger 10 arranged on the suction side of the exhaust air fan 6, the determined mass flows of outside air AL and supply air ZL are preferably balanced with a formula, as shown in FIG.

By monitoring the glass tubes an impermissible moistening of the dry process air can be avoided by the highly loaded exhaust air at a glass tube breakage.

All measured value calculations are preferably pressure- and temperature-compensated.

With the long-term recorded in the evaluation device 7 or the process control system 8 data, the heat recovery system can be additionally evaluated in terms of its efficiency, possibly optimized or renewed.

Optionally, contamination and / or blockage on or in the heat exchanger 10 can also be monitored on both transmission sides based on system changes. For this purpose, at least one additional differential pressure sensor is used to measure a pressure difference between the inlet 21 and the outlet 22 or preferably between the inlet 23 and the output 24 of the heat exchanger 10 is provided, preferably in the sensor devices 11 and 12 or 13 and 14. Thus, the availablen availability and maintenance planning is improved. In an optimization function for the air-air heat recovery in the heat exchanger 10 as an additional option, an optimization of the heat flow capacities of the evaluation device 7 can be carried out with the aid of the calculated data. Thus, an optimal energy utilization is guaranteed at every operating point.

In an optional optimization function for the air-water heat recovery in the heat exchanger 30, an optimization of the heat flow capacities of the evaluation device 7 can be carried out with the aid of the calculated data and additional use of volume flow measurement in the water circuit 32 (for example ultrasound measuring device). Thus, optimal energy utilization is ensured in each operating point.

In particular, the efficiency or the heat transfer can be optimized by the heat flow capacity of a heat medium, ie AL or ZL in the heat exchanger 10 or water in the water circuit 32 of the heat exchanger 30, on the one hand and the heat flow capacity of the other heat medium, ie ABL or FL, on the other be set equal to each other. The heat flow capacity corresponds to the product of heat capacity and mass flow of the heat transfer medium. Therefore the mass flow of at least one medium, e.g. AL or the water, while the mass flow of the other medium, e.g. ABL, may be led through the process.

Of course, in all embodiments, the numerical calculation does not have to follow the stepwise sequence of the physical formulas, but can also use equations solved to reduce rounding errors immediately after the input variables, for example the temperature t or the relative humidity φ. LIST OF REFERENCE NUMBERS

2 Process area 3 Air inlet 4 Air outlet 5 Supply air fan 6 Exhaust air fan 7 Evaluation unit 8 Process control system 9 Display unit 10 Heat exchanger 11 to 14 Sensor unit 16, 17 Sensor unit 21 Input 22 Output 23 Input 24 Output 30 Heat exchanger 32 Water circuit AL Outdoor air ZL Supply air ABL Exhaust air FL Exhaust air

Claims

claims

1. A method for determining a state of a heat transfer device through which at least two heat media flow and in which takes place in a heat transfer process a heat transfer zwi¬ tween the at least two heat media, wherein a) during the heat transfer process at least one physical metric measure at least one b) from the measured values or measuring signals of the measured variable (s), an associated value of at least one physical state variable which depends on the measured variable (s) and which characterizes or describes the state of the heat transfer device is determined becomes.

2. The method of claim 1, wherein a temperature is provided as a measured variable of at least one of the heat media or is.

3. The method of claim 1 or claim 2, wherein as a measured variable of at least one of the heat media, a volume flow of Wärmeme¬ dium or one with the volume flow of the heat medium in ein¬ significant relationship standing physical, such as a differential pressure or pressure in the heat medium provided is or becomes.

4. The method according to one or more of the preceding claims, wherein at least one of the heat media is gaseous and / or consists essentially of air and water and / or air from the earth's atmosphere.

5. The method of claim 4, wherein as the measured variable, the relative humidity or the absolute humidity or one with the relative humidity or the absolute humidity in clear connection physical size, in particular the dew point temperature, of the or each gaseous heat medium is or is provided.

6. The method according to one or more of the preceding claims, wherein at least one of the heat media is liquid and / or we least consists predominantly of water.

7. The method according to one or more of the preceding claims, wherein at least one measured variable of at least one of the Wärmeme¬ diene is measured both before flowing through the heat transfer device and after flowing through the heat transfer device.

8. The method according to one or more of the preceding claims, wherein as the state of the heat transfer device, in particular the heat transfer process in the Wärmeübertragungs¬ device, characterizing or descriptive state variable temperature efficiency is determined, preferably the Quo¬ients from the difference the measured temperature value of the heat medium to which the heat is transferred, before flowing through the heat transfer device and the measured temperature value of this heat medium after flowing through the heat transfer device on the one hand and the difference of the Tem¬ temperature value of the heat medium from which the heat is subtracted, before Flowing through the heat transfer device and the temperature value of this heat medium after flowing through the heat transfer device on the other hand corresponds.

9. The method according to one or more of the preceding claims, wherein as the state of the heat transfer device, in particular the heat transfer process in the Wärmeübertragungs¬ device, characterizing or descriptive state variable heat quantity efficiency is determined, preferably the Quotient of the mass density of the heat medium with which the heat is transferred, preferably dense-compensated, with the heat medium, after the heat transfer device has passed through the multiplied enthalpy of the heat medium to which the heat is transferred, before the heat transfer device flows through it and the enthalpy of this heat medium after flowing through the heat transfer device on the one hand and the, preferably densely compensated, mass flow of Wär¬ memediums from which the heat is removed, after Durch¬ flow of the heat transfer device multiplied difference of the enthalpy of the heat medium, deducted from the heat is, after flowing through the heat transfer device and the enthalpy of this heat medium before flowing through the heat transfer device on the other hand corresponds.

10. The method according to one or more of the preceding claims, wherein as the state of the heat transfer device, in particular the heat transfer process in the Wärmeübertragungs¬ device, characterizing or descriptive state variable, the transmitted heat output is determined, preferably the Pro¬ product from the density-compensated mass flow of the heat medium to which the heat is transferred, on the one hand, and the difference in the enthalpy of this heat medium before flowing through the heat transfer device and the enthalpy of this heat medium after flowing through the heat transfer device, on the other hand.

11. The method according to one or more of the preceding claims, wherein as the state of the heat transfer device, in particular the heat transfer process in the Wärmeübertragungs¬ device, characterizing or descriptive state variable heat transfer, preferably by integration or summation of the heat output over time , is determined.

12. The method according to one or more of the preceding claims, wherein the enthalpy of the heat medium is determined from the measured values of the temperature and the relative or absolute humidity of one or each gaseous heat medium.

13. The method according to one or more of the preceding claims, wherein from the measured values of the temperature and the relative Feuch¬ te of one or each gaseous heat medium, the absolute humidity of the heat medium is determined.

14. The method according to one or more of the preceding claims, wherein the density of the heat medium is determined from the measured values of the temperature and the absolute or relative humidity of one or each gaseous heat medium.

15. The method according to one or more of the preceding claims, wherein the dew point temperature of the heat medium is determined from the measured values of the temperature and the absolute or relative humidity of one or each gaseous heat medium.

16. The method according to one or more of the preceding claims, wherein from the measured values of the temperature and the absolute or relative humidity on the one hand and the volume flow or with the volume flow of the heat medium in a unique relationship ste¬ Henden physical size, in particular the differential pressure or pressure, on the other hand, a density-compensated volume flow or mass flow of one or each gaseous heat medium is determined.

17. The method according to claim 16, wherein the density-compensated volumetric flow is the quotient of the measured volumetric flow or of the corresponding measured physical variable, in particular particular the differential pressure or pressure, determined volume flow on the one hand and the square root of the density, in particular the determined density, is proportional or is determined.

18. Method according to claim 16, wherein the density-compensated mass flow is the product of the measured volumetric flow or the volumetric flow determined on the basis of the corresponding measured physical variable, in particular the differential pressure or pressure, and the square root of the density, in particular the average density, is proportional or is determined.

19. The method according to one or more of the preceding claims, wherein a leakage, in particular a fracture or crack, in the heat transfer device is detected, in particular by Auswer¬ tion of the absolute humidity and / or, preferably dichtekom¬ pensierten, mass flow at least one of the heat media before and after flowing through the heat transfer device.

20. The method according to one or more of the preceding claims, wherein the amount, in particular the, preferably dichtekompen¬ sated, mass flow, of ent¬ in the heat transfer device stating condensate at least one heat medium, in particular the heat medium from which the heat is removed, from the, in particular density-compensated, mass flows of this Wärmeme¬ diums before and after flowing through the Wärmeübertragungseinrich¬ device is determined.

21. The method according to one or more of the preceding claims, wherein the temperature of formed in the heat transfer device condensate at least one heat medium, in particular the heat medium to which the heat is transferred, determined by evaluating the temperature and relative humidity of this Wärmeme¬ dium is measured or measured directly.

22. Method according to one or more of the preceding claims, in which the measured values of at least one measured variable and / or the determined values of at least one state variable characterizing or describing the state of the heat transfer device and / or the determined values of at least one on the basis of Measured values or measured signals determined physical size on at least one display device, in particular a process control system or a control room or monitoring and / or Kontroll¬ wait, be displayed or dar¬ during the heat transfer process.

23. Method according to one or more of the preceding claims, in which the measured variable (s) is / are measured during a large number of measuring processes during a heat transfer process, and in which preferably the measured values or measuring signals are stored from a plurality of measuring operations and for Assessment of the state of the heat transfer device is made available or evaluated.

24. The method according to one or more of the preceding claims, in which a contamination or clogging device in the Wärmeübertra¬ er¬ by measuring a differential pressure of at least one of the heat media at the heat transfer device er¬ known or determined.

25. The method according to one or more of the preceding claims, wherein each of the product of the heat capacity and the determined, preferably density-compensated, mass flow corre sponding heat flow capacities of the two heat media are substantially equal to each other adjusted by Stellen least one of mass flows.

26. A method for conditioning a process area, in which a) at least one fluid feed medium is supplied to the process area and b) at least one fluid discharge medium is removed from the process area, c) the feed medium and the discharge medium are guided through at least one heat transfer device and heat is transferred from the discharge medium into the supply medium or from the supply medium into the discharge medium b, d) a process according to one or more of the preceding claims is carried out or used to determine the state of the heat transfer device becomes.

27. The method of claim 26, wherein the feed medium and / or the discharge medium is gaseous.

28. The method of claim 27, wherein the supply medium and / or the discharge medium contains water or moisture.

29. An apparatus for determining a state of a heat transfer device, through which at least two heat media flow and in which a heat transfer takes place between the at least two heat media in a heat transfer process, comprising a) at least one measuring device for measuring at least one physi cal At least one evaluation device which is connected to each measuring device and from whose measured values or measuring signals of the measured variable (s) at least one associated value of at least one of the measured variable (s) and the state of heat transfer tragungsseinrichtung characterizing or descriptive physika¬ cal state quantity determined.

30. Apparatus according to claim 29 for carrying out a method according to one of claims 1 to 28.

31. The apparatus of claim 29 or claim 30, wherein the measuring device a) an input of the heat transfer device for a first of the heat media associated first sensor means for measuring at least one measure of the first heat medium before Durch¬ the Wätmeübertragungseinrichtung, b) a one C) a third sensor device assigned to a further input of the heat transfer device for a second of the heat media for measuring at least one measured variable of the second heat medium before flowing through the heat transfer device and d) a fourth sensor device assigned to an output of the heat transfer device for the second heat medium for measuring at least one measured variable of the second heat medium h Durch¬ flow of the heat transfer device comprises.

32. Device according to one of claims 29 to 31 with at least one display device, in particular a process control system or a control room or monitoring and / or control room, for displaying conditions of the current values of the state variable (s), measured variable (s) and / or out the measured variable (s) of derived physical quantity (s).

33. Device according to one of claims 29 to 32, wherein at least two heat transfer devices are connected one behind the other in the flow path of one of the heat mediums and each heat transfer device removes heat from this heat medium and transfers it to another heat medium.