Air-cooled condenser, steam power plant and method

Abstract

The invention relates to an air-cooled condenser (1) for liquefying a working fluid, comprising a line arrangement (6) extending from an inlet (IN) to an outlet (OUT), along which the working fluid is guided and liquefied by heat dissipation, wherein the line arrangement (6) includes at least one line section (8) having an angle of inclination (α) that defines a gradient with respect to a flow direction of the working fluid. The objective of increasing the energy efficiency is achieved by making the angle of inclination (α) of the line section (8) adjustable by means of an actuating drive (4) coupled to the line section (8) for setting the angle of inclination (α).

Description

[0001] The invention relates to a condenser according to the preamble of claim 1, a steam power plant according to claim 10 with such a condenser, and an associated control method according to claim 11.

[0002] A condenser is a system through which a working fluid continuously flows, and in which the state of the working fluid is changed completely or partially from vapor to liquid by heat transfer. Condensers are used in systems with thermal cycles. For example, they are used in refrigeration systems for generating cold or in power generation plants for producing electricity. In air-cooled condensers, excess heat is released to the environment via forced or natural convection.

[0003] Often, it is sufficient to achieve a degree of subcooling of the working fluid in the condenser that guarantees it liquefies reliably, cools to a defined target temperature, and thus becomes pumpable again. Further subcooling is generally undesirable, as the energy contained in this additional subcooling must be reintroduced in subsequent process steps such as preheating, evaporation, and superheating, and therefore represents an energy loss.

[0004] To control the subcooling of the working fluid in a condenser, it is known to actively regulate the cooling capacity of a fan (synonym: ventilator), for example, by adjusting the fan speed. It is also known to more or less cover the pipe sections carrying the working fluid with adjustable cover plates in order to actively control the airflow striking the pipe sections and thus the heat dissipation. However, this has the disadvantage, among others, that the desired change in heat dissipation only occurs with a time delay due to thermal inertia, and generating an airflow striking the cover plates represents unnecessary reactive power. Furthermore, complex actuators are required to control a large number of individual cover plates. Examples of airflow control in the prior art are shown in documents FR2982936B1, DE1962061C3, and GB974691A. Reference is also made to DE10 2019 122 087 A1.

[0005] CN 220689832 U discloses a liquid-cooled condenser in which the inclination can be adjusted to prevent clogging. CN 212673875 U discloses a water-cooled condenser with adjustable inclination.

[0006] Despite the progress mentioned above, the task remains to further increase the energy efficiency of condensers and condenser-related equipment.

[0007] The problem is solved by the subject matter of claims 1, 10 and 11.

[0008] According to the invention, an air-cooled condenser for liquefying a working fluid (synonym: working medium) is proposed. The condenser comprises a pipe arrangement extending from an inlet to an outlet, along which the working fluid is guided and liquefied by heat dissipation. The pipe arrangement can also be referred to as a condensing section.

[0009] The pipe assembly comprises at least one pipe section extending between two points. This pipe section may have an angle of inclination. The angle of inclination can be defined as the angle between the line defined by the two points and a horizontal line. The angle of inclination defines a gradient (in %) with respect to the flow direction of the working fluid. If the angle of inclination is 0°, the gradient is 0%. If the angle of inclination is +45°, the gradient is 100%; if it is -45°, the gradient is -100%. Thus, each pipe section can be assigned an angle of inclination and a corresponding gradient.

[0010] A condenser according to the invention is characterized in that the inclination angle of the at least one pipe section is adjustable by means of an actuating mechanism. The term "adjustment" refers to adjustment in an operational state and, in particular, while the working fluid is flowing through the condenser. "Adjustment" thus does not refer to setting an initially fixed and practically unchangeable inclination angle of the pipe section during the initial installation of the condenser. By adjusting the inclination angle (and thus the gradient), the force of gravity acting on the working fluid in the pipe section can be altered, which in turn changes the flow velocity and thus the residence time of the working fluid in the liquid or partially liquid state in the pipe section.Consequently, this can influence the effective heat transfer and thus the temperature of the working fluid at the end of the pipe section. If a shallower, positive inclination angle (i.e., a shallower gradient) is used, the average residence time of the working fluid increases, and thus the effective amount of heat that can be dissipated through the pipe section increases, causing the temperature at the end of the pipe section to decrease, all other things being equal. If a steeper, positive inclination angle (i.e., a steeper gradient) is used, the average residence time of the working fluid in the pipe section decreases, so less heat energy can be dissipated to the environment through the pipe section, and the temperature at the end of the pipe section increases, all other things being equal.

[0011] One advantage of the invention is that the effective heat transfer, and consequently the resulting subcooling, can be changed practically instantly. A time delay before the effect takes hold, such as that which typically occurs when changing fan speed due to inertial effects (heat capacities of pipes and the like), is practically eliminated. Furthermore, angle adjustment is mechanically simple to implement.

[0012] The core of the invention therefore lies in the fact that the subcooling of the working fluid can be adjusted by changing the effective residence time of the working fluid in the condenser and in particular a section of its piping.

[0013] Therefore, costly measures to change the heat transfer performance in the condenser, such as adjustable air shading flaps, can be omitted or at least minimized.

[0014] Further features and advantageous embodiments of the invention will become apparent from the dependent claims and the following description.

[0015] The condensation process is advantageously independent of pressure. This means that the pressure within the condenser, and in particular the pressure in the condensation section as well as at the inlet and outlet of the condenser, remains essentially constant. Pressure relief devices, such as throttles or throttle-like elements, which reduce the pressure of the working fluid and thus induce condensation, are also unnecessary.

[0016] The actuator for adjusting the tilt angle of at least one pipe section can be advantageously an automatic actuator. Suitable automatic actuators include, for example, electromechanical, hydraulic, or pneumatic actuators, as well as combinations thereof, such as electrohydraulic actuators. The actuator can also be remotely operated. Of course, manual actuators that can be adjusted manually at defined intervals are also conceivable instead of an automatic actuator. However, an automatic actuator is preferred because it enables, in particular, automated, computer-monitored control of the tilt angle.

[0017] In advantageous embodiments of the condenser according to the invention, the pipe section can be a rigid pipe section, such as a tube or a tube bundle. The rigid pipe section can extend from the inlet to the outlet of the condenser. Alternatively, the rigid pipe section can also be a flexible pipe section or a pipe section composed of a plurality of individual rigid or flexible segments.

[0018] The line arrangement can consist of a single rigid line section. However, it can also consist of a multitude of line sections arranged fluidically in series and / or in parallel, whereby either one, some, or all line sections can be adjusted in their respective angles of inclination via a single actuator or several actuators assigned to each line section.

[0019] If the piping arrangement consists of exactly one pipe section, the entire piping arrangement has the same angle of inclination for fixed capacities. If the piping arrangement comprises multiple fixed pipe sections that can be adjusted separately via separate actuators, the flow velocity and thus the residence time of the working fluid in the individual pipe sections can also be set independently of one another. This makes it possible, in principle, to provide different cooling capacities along the condensing line by varying the residence times in individual pipe sections. Individual pipe sections are preferably identical or at least of a similar design.

[0020] In a preferred embodiment of the invention, the pipe arrangement can be a finned heat exchanger with air-flowed fins arranged on the pipes and pipe sections, wherein the fins increase the heat transfer surface and thereby improve the cooling performance.

[0021] The pipes can be designed as a multitude of parallel, vertically and / or horizontally arranged pipes, one above the other and / or next to each other, extending between a distribution pipe and a collecting pipe. In this configuration, the distribution pipe forms or comprises the inlet and the collecting pipe the outlet.

[0022] The distributor and collector pipes can be located on the same side of the condenser, e.g., on the left side. In this case, the piping runs a certain distance away from the distributor pipe, e.g., to the right, then reverses direction and runs back to the collector pipe. Such an arrangement is also known as a two-pass register, since the working fluid passes through the same condensing section twice, namely on the outward and return journeys.

[0023] The distribution and collection pipes can, however, be located on different sides of the condenser. In this case, the pipework runs from one side of the condenser, e.g., the left, to the other side, e.g., the right. Such an arrangement is also known as a single-pass register, since the working fluid passes through the condensing section exactly once. Configurations as multi-pass registers with more than two passes, e.g., as three-pass or four-pass registers, are possible.

[0024] In a preferred embodiment of the invention, the at least one pipe section is rotatably mounted about a horizontal axis for adjusting the angle of inclination or gradient. This can be achieved, for example, by rotatably suspending the pipe assembly in a frame. The angle of inclination is preferably rotatable in the positive direction by an angular difference of at least +2°, +3°, +5°, or more than +7.5°. A positive direction of rotation means that the rotation occurs in the direction of the maximum positive angular position. As a result, in the positive angular range—starting from the horizontal—the positive gradient becomes steeper and the flow velocity of the working fluid increases.

[0025] The inclination angle is preferably also rotatable negatively by an angular difference of at least -2°, -3°, -5° or more than -7.5° in the negative direction of rotation. Negative direction of rotation means that the rotation occurs in the opposite direction to the maximum positive angular position. This results, in the positive angular range – starting from the horizontal – in a shallower positive gradient and a lower flow velocity of the working fluid. The gradient of the pipe section and / or the gradient of the entire pipe assembly can advantageously be limited upwards, in particular to an absolute inclination angle of less than +20°, +10° or less.

[0026] As explained above, the specified angles are to be understood as absolute angles relative to the horizontal (i.e., 0°). At an angle of 0° – which is equivalent to a slope angle of 0° – the gradient is 0%. At +5°, the working fluid flows down a gradient of +8.75% in the intended flow direction. At -5°, the working fluid flows "backwards" against the intended flow direction, down a gradient of -8.75%.

[0027] Other ways of influencing flow velocity by changing the gradient are also possible. For example, this can be achieved by raising or lowering a point in a flexible pipe section relative to another point in the same pipe section, thereby changing the radius of curvature of the flexible pipe section.

[0028] Advantageously, the condenser has at least one actively operated fan to generate an airflow directed onto the at least one pipe section, cooling it by forced air convection. The fan is preferably arranged on the top of the condenser and generates a substantially upward-directed, suction airflow. The fan can be positioned on the condenser independently of the pipe arrangement and pipe section. However, it is advantageous if the fan is mechanically fixed to the at least one pipe section so that the fan moves with the pipe section. This has the advantage that the relative direction of the airflow does not change, or at least not significantly, even if the angle of inclination of the pipe section changes. This can, among other things,This can be significant if the condenser's vanes or other air guidance devices are optimized for a specific airflow direction, and a change in the angle of inclination would otherwise cause, for example, increased air resistance (and thus increased reactive power).

[0029] Of course, the condenser can also be designed as a passive air-cooled condenser. For example, the condenser can be designed as a cooling tower known from the prior art, in which an airflow is generated by the chimney effect. Furthermore, other types of passive air-cooled condensers are also conceivable.

[0030] Advantageously, the condenser has a control device for controlling (synonymous: regulating) the automatic actuator and suitable sensor means connected to the control device for detecting at least one measured variable of an operating and / or environmental parameter of the condenser.

[0031] The sensor means preferably comprise at least one sensor for directly or indirectly determining the inclination angle of the condenser pipe section, e.g., an angle detection device. Only the determination of the actual value of the inclination angle allows the comparison of the inclination angle between an actual and a target value.

[0032] Suitable operating or environmental parameters can include internal parameters such as the temperature and / or pressure of the working fluid at, before, and / or after the inlet and / or outlet of the condenser. External parameters can include the ambient temperature of the condenser, a time period, a weather phenomenon such as air pressure or humidity, or wind speed. A rain sensor can also be useful for recording the type and amount of precipitation.

[0033] The operating or environmental parameters may also include parameters of a system connected to the condenser that directly or indirectly provide information about the expected heat load to be handled by the condenser, e.g., a utilization factor, such as a characteristic value of a connected turbine, a temperature characteristic of the working fluid, etc.

[0034] Suitable measured variables can also include the pressure and / or temperature in the pipe section, the manifold, and / or a collection tank (synonymous with tank or buffer tank) located downstream of the manifold. The fill level of the collection tank can also be a relevant measured variable for the control system to ensure that sufficient working fluid is available at all times and that the collection tank does not run dry.

[0035] The control unit is designed to regulate the actuator in real time or predictively to adjust the inclination angle of the line section based on the recorded measurement variable(s).

[0036] The regulation is preferably carried out in such a way that the working fluid reaches a specific target temperature (with any necessary safety margin) at a key point at and / or after the outlet of the condenser, which is necessary at a given specific pressure in the condenser to achieve the desired liquid state of matter of the working fluid at the outlet.

[0037] The control unit can also be configured to control other components of the condenser, such as a fan.

[0038] The condenser is additionally equipped with a preferably wireless communication device for bidirectional communication between the control unit and an external device, such as a higher-level control center (e.g., an internet-enabled server located elsewhere). This allows, for example, software updates to be installed on the control unit, remote maintenance and diagnostics to be performed, and external control commands to be received and forwarded to the control unit to change the inclination angle of the pipe section. Using this communication device, it is then possible, for example, to control the condenser and, in particular, the inclination angle of the pipe section proactively, depending on, for example, a weather forecast for the condenser's location.Bidirectional communication also enables the return of performance data from the condenser or an associated system to the higher-level control center for further evaluation.

[0039] In a useful further development of the invention, the piping arrangement of the condenser can comprise two (or more) fluidically connected in series and / or parallel finned heat exchangers with substantially horizontally extending piping sections, wherein the (at least two) finned heat exchangers are arranged in a V-shape relative to each other.

[0040] Each finned heat exchanger consists of a plurality of parallel and superimposed pipe sections within the respective finned heat exchanger, extending essentially horizontally in a main direction. At least one first and at least one second finned heat exchanger are geometrically mirror-symmetrical and arranged at an angle to each other such that the finned heat exchangers form a V-shape, with the pipe sections of the first and second finned heat exchangers running parallel to each other. Such a V-shaped arrangement is very compact, as a large number of pipe sections can be supplied with a cooling airflow by a single fan.

[0041] In other embodiments of the invention, the finned heat exchanger(s) can also be configured as a table-top cooler, i.e., in a flat arrangement. Details regarding the design of both a table-top cooler and a condenser with V-shaped finned heat exchangers are well known to those skilled in the art and require no further explanation here. A vertical or parallel arrangement of the finned heat exchangers relative to each other would also be conceivable.

[0042] A further useful development could involve combining, for example, two coolers (condensers), where the condensers are positioned opposite each other at the inlet and outlet ends, and in particular, a common collection tank is used. The inlets can be fed, for example, by a distribution device (dividing the main mass flow of the working fluid coming from the turbine), and the outlets can be connected, for example, by a common collection tank.

[0043] In further variations of the invention, the condenser can also be designed as an adiabatic cooler (synonym: evaporative cooler). An adiabatic cooler is characterized by the fact that a cooling airflow is passed through moisture-soaked mats, which are arranged upstream of the piping system carrying the working fluid. Evaporation lowers the temperature of the cooling airflow. This allows, for example, use even at higher ambient temperatures or the use of working fluids with lower condensation temperatures. An example of an adiabatic cooler is shown in FR2982936B1, which was mentioned at the beginning.

[0044] The condenser according to the invention is preferably part of a power generation plant in which the working fluid is cyclically evaporated and condensed. In particular, the evaporated working fluid is passed through a turbine, which performs mechanical work to drive an electric generator. The fluid is then liquefied in the condenser and returned to the heat input. Such a plant can be called a steam power plant. A steam power plant can also be used, in particular, for the recuperation of waste heat in a heat recovery cycle, whereby waste heat from a primary energy generator, such as an internal combustion engine or a gas turbine, is fed into the steam power plant cycle to provide more thermal energy to the cycle.The steam power plant is expediently operated with an organic working fluid for carrying out a Rankine cycle, which can also be operated at lower temperatures than water (steam). A steam power plant in which the condenser could be used is shown, for example, in DE102019122087A1, the contents of which are incorporated into the disclosure of this document by reference.

[0045] A steam power plant according to the invention comprises, viewed in the direction of flow, at least one pump device for circulating the working fluid in the circuit, optionally a first side of a recuperator for coupling excess heat into the working fluid, optionally a single- or multi-stage preheater for raising the temperature level of the working fluid, a single- or multi-stage evaporator for evaporating the working fluid, optionally a single- or multi-stage superheater for superheating the working fluid, a turbine generator for expanding the working fluid while delivering mechanical work to generate electrical energy, optionally a bypass line to bypass the turbine generator, and - where applicable - the second side of the aforementionedRecuperators for extracting heat from the working fluid, the condenser described above for condensing the working fluid, and optionally a collection tank for intermediate storage of a sufficient volume of working fluid, from which the pump device feeds working fluid into the circuit.

[0046] Typical performance levels of a condenser according to the invention range from 20 to 500 kWth (thermal cooling capacity). The condenser is preferably installed outdoors and cooled with ambient air (-25 °C to +45 °C). It can be designed for mass flow rates (working fluid) between 0.1 and 5 kg / s. Such condensers are particularly suitable for integration into steam power plants with electrical outputs of around 5 to 250 kW.

[0047] Another aspect of the invention describes a control method for a condenser, which is particularly suitable for operating a previously described condenser. In a first control loop, the method according to the invention regulates the inclination angle of a condenser pipe section through which a working fluid to be condensed flows, in order to influence the average residence time of the working fluid in the pipe section by adjusting the gradient and thus the flow velocity. This allows the heat transfer between the working fluid and the pipe section to be increased or decreased. The overarching goal of the control method is to achieve a target temperature at and / or after the condenser outlet that is low enough to reliably condense the working fluid, but not lower. The control is based on at least one measured variable.

[0048] In one embodiment of the control procedure, the actual temperature T1 of the working fluid at and / or after the condenser outlet is used as (at least one) measured variable. This can be the temperature of the working fluid directly in the condenser's manifold, the temperature in a downstream storage tank, or both (by calculating an average). The slope angle is reduced when the temperature T1 exceeds a predetermined upper threshold or when such an exceedance is predicted, in order to decrease the flow velocity and thereby increase heat dissipation. Simultaneously, the slope angle is increased when the temperature T1 falls below a predetermined lower threshold or when such a fall below is predicted.This ensures that the temperature of the working fluid remains within desired limits even without intervention in other control variables (such as increasing fan power or reducing the thermal load input into the working fluid by reducing the load of a steam power plant).

[0049] Advantageously, the control of the inclination angle is additionally regulated depending on the fill level of the working fluid in an intermediate storage, in particular the collecting pipe or a collection container downstream of the collecting pipe.

[0050] The system is designed so that the minimum permissible positive downward tilt angle is limited and, if necessary, increased if the fill level falls below a predetermined value or if a drop below this value is predicted. By increasing the positive tilt angle, the average flow rate of the working fluid can be increased, thus making the working fluid available more quickly at the outlet or in the collection tank. This ensures that sufficient working fluid is maintained in the intermediate storage tank and that it does not run dry.

[0051] Since less heat can be carried away from the working fluid due to a higher flow velocity, the cooling capacity of the condenser lost due to the increased angle may need to be compensated for in other ways, such as by higher fan power and / or (in the case of adiabatic coolers) a reduction in the intake temperature.

[0052] Since ensuring an adequate supply of working fluid takes precedence over sufficient subcooling, the level-related control is implemented in a dominant manner compared to the aforementioned temperature control.

[0053] Advantageously, the control method includes a second control loop for regulating the fan speed. In this second loop, the fan speed is regulated to a first target fan speed based on a pressure measurement taken at the condenser inlet, upstream of it, or both, particularly as the outlet pressure of a turbine. The target fan speed is increased when the slope of the pipe section reaches a permissible minimum value at which the condenser's cooling capacity cannot be increased by further reducing the slope, for example, because this would result in a negative slope (negative angle) and the working fluid would flow back upstream.

[0054] In other words, the control system for regulating the temperature of the working fluid comprises, in a first step, controlling the angle of inclination to adjust the cooling capacity by changing the flow velocity, and—if necessary—in a second step, adjusting the fan speed to further increase the cooling capacity. Controlled variables can be the pressure and temperature of the working fluid. Manipulated variables are the angle of inclination of the pipe section and the fan speed. Boundary conditions, such as a required fill level, can define or modify maximum permissible limits.

[0055] In a preferred embodiment of the invention, the change in the inclination angle occurs discontinuously at intervals between control points, such that the inclination angle or gradient of the pipe section is changed a maximum of 15 times per hour or less frequently. Such limited adjustment dampens the control loop, prevents overshooting, and reduces, in particular, mechanical wear caused by (too) frequent adjustment of the inclination angle.

[0056] Preferably, the condenser or the fluid circuit associated with the condenser for the working fluid includes leak detection means suitable for detecting a leak in the fluid circuit. A leak can be detected indirectly, for example, by monitoring the level change over time in an intermediate storage tank. If the level decreases over time under otherwise unchanged conditions, this indicates a (minor) leak. However, it is also possible to detect a leak, for example, via a pressure drop. Other methods of leak detection remain unaffected.

[0057] Leakage monitoring devices are advantageously used to negatively adjust the inclination angle of the pipe section in the event of an actual or even just suspected leakage.

[0058] Advantageously, a distinction is made between the case of a gradual leak (continuous but minor loss of working fluid) and a sudden leak (sudden leak with massive loss of working fluid).

[0059] In the event of a sudden leak, the condenser is immediately moved to a safety position with maximum cooling capacity, in which the pipe section is adjusted to a maximum negative angle of inclination, so that the working fluid can essentially no longer flow towards the condenser outlet. This allows the working fluid to be retained in the condenser and at least the amount of escaping working fluid to be minimized.

[0060] In the case of a slow leak, it may initially be sufficient to limit the downward angle of the pipe section to a minimal positive angle (the pipe section's inclination angle is therefore always at or above this minimum positive angle). This allows the working fluid to flow more quickly through the condenser, and thus be available for recirculation at the condenser outlet more rapidly. Since this reduces the time required for the working fluid to complete a full circuit, a smaller quantity of working fluid is needed to maintain the operation of the system connected to the condenser. A shorter circulation time can therefore compensate for a certain degree of working fluid loss.

[0061] The control method can advantageously determine the target gradient of the pipe section based on at least one measured value of a process or environmental parameter of the condenser or of the overall system comprising the condenser. In this process, at least one measured value of a process or environmental parameter of the condenser and / or the overall system is determined, and based on this at least one measured value, a target gradient (i.e., an angle of inclination) for the condenser pipe section is selected from a data set. The data set contains target gradients for the specific measured value(s) of the measured value(s). The gradient or angle of inclination of the pipe section is then adjusted accordingly.

[0062] The dataset may have been determined based on model values ​​from a theoretical calculation model, whereby the target slope was determined with respect to a parameter to be optimized. Since the determination of a suitable target slope angle depends on a multitude of external influencing factors, the dataset is advantageously based on the evaluation of empirically determined data from process and / or environmental parameters of the condenser, a system connected to the condenser, and / or structurally identical or similar condensers or systems. The evaluation of the empirically collected data can be carried out, for example, using statistical methods and / or machine learning with regard to the relationship between an existing slope (or slope angle) of the condenser in question and a parameter to be optimized, in particular...The energy efficiency of the condenser or a system connected to the condenser is evaluated, and correlations between the gradient and the parameter to be optimized are determined, so that a target gradient can be derived for each specific overall situation from the available measured values, which has been stored in the data set for retrieval by a control unit.

[0063] This data set can also be continuously updated, especially if individual liquefiers have (wireless) communication interfaces.

[0064] Relevant measurement parameters from which control parameters for the control procedure for adjusting the tilt angle can be derived, and which expediently lead to an increase in the efficiency of the overall system, are, for example: The electrical power output of a primary energy generator such as a gas turbine or an internal combustion engine, measured values ​​from a heat source feeding the steam power plant, such as an exhaust gas stream and / or a cooling circuit (e.g. volume flows or volume flow changes, temperature or temperature changes, mass flow or mass flow changes, etc.) and / or a coupling circuit thermally connected to the heat source and / or an energy transfer circuit thermally connected to the heat source, such as a water or thermal oil circuit, the electrical power output of a turbine generator or expansion turbine generator, or combinations thereof.

[0065] An embodiment of the invention is explained in more detail below with reference to the accompanying figures.

[0066] This shows Fig. 1 a liquefier according to the invention in perspective view from two viewing directions ( Fig. 1A und 1B ) in a neutral position, Fig. 2 the liquefier Fig. 1 in a side view ( Fig. 2A ) and a frontal view ( Fig. 2B ) in neutral position, Fig. 3 the liquefier Fig. 1 in a side view with positive tilt angle α - state: positive tilt angle control of the condenser in operation -, as well as Fig. 4 the liquefier Fig. 1 in a side view with negative tilt angle α - state: safety position-.

[0067] In the Fig. 1A Figure B shows a condenser 1 according to the invention. It comprises a cuboid frame 2 with four horizontal longitudinal struts 2a, four horizontal transverse struts 2b, and four vertical struts 2c, each arranged at right angles to the others. Two longitudinal struts 2a together with two vertical struts 2c define a front and a rear longitudinal side, and the transverse struts 2b together with two vertical struts 2c define a front and a rear end face of the condenser 1. The frame 2 is aligned horizontally with respect to the ground by means of four leveling or adjustable feet, i.e., the gravity vector g and the vertical struts 2c run parallel.

[0068] Within the frame 2, a rectangular subframe 3 with two longitudinal struts 3a and two transverse struts 3b is arranged. The subframe 3 is rotatably mounted on one side along the longitudinal axis of a transverse strut 3b about a horizontal axis of rotation X relative to the frame 2. On the opposite side, the subframe 3 is supported against the frame 2 by an electric actuator 4. By means of the actuator 4 – which is rotatably mounted at both mounting points to the frame 2 and the subframe 3 – the subframe 3 can be rotated about the horizontal axis of rotation X and thus its inclination adjusted.

[0069] On the intermediate frame 3, two finned heat exchangers 5a and 5b are arranged in a V-shape relative to each other. Each of the two finned heat exchangers 5a and 5b has a distribution pipe 5a-1, 5b-1 and a collecting pipe 5a-2, 5b-2 on the front end face of the condenser 1, which serve as the inlet (IN) and outlet (OUT) for the working fluid of a fluid circuit. The type of heat exchanger is not essential for the invention.

[0070] From each distribution pipe 5a-1, 5b-1, a pipe arrangement 6 extends horizontally (in neutral position) to the opposite end face of the condenser 1, reverses direction there, and leads back to the respective collector pipe 5a-2, 5b-2 of the finned heat exchanger 5a, 5b. In the present embodiment, each pipe arrangement 6 consists of a plurality of parallel pipes 6', 6", 6‴, ..., (see Figure 1). Fig. 2A Each of the pipes 6, 6', 6", ..., is U-shaped and runs horizontally in a plane. Each pipe 6 thus has a first pipe section 8-1 extending away from the distribution pipe 5a-1, 5b-1 and a second pipe section 8-2 converging on the collecting pipe 5a-2, 5b-2. The individual pipes 6, 6', 6", ..., are supported perpendicular to the pipes by the fins (not shown) and thermally connected to them.

[0071] In this embodiment, two electrically operated fans 7 are arranged on the top of the condenser 1. These fans are indirectly attached to the intermediate frame 3 via the finned heat exchangers 5a, 5b and are also movable with the frame. The fans 7 generate a substantially vertical, upward-directed suction airflow that draws air laterally through the individual fins, as indicated by the thick, black arrows in the diagram. Fig. 2B This is shown only as an indication. The air convection thus forced cools the fins and the pipes 6; 6', 6", ..., and consequently also the working fluid flowing through the pipes 6, 6', 6", .... To protect the fins from excessive soiling, the air filter units 9a / b (optional) are mounted in the intermediate frame 3.

[0072] During operation, a working fluid, for example an organic working fluid with evaporation temperatures around 300 K (at normal pressure), is introduced in vapor form via the respective inlet EIN on the distribution pipes 5a-1, 5b-1 and distributed via the distribution pipes 5a-1, 5b-1 to the multitude of parallel outgoing pipe sections 8-1 (not shown), i.e., divided into a multitude of individual partial flows. The working fluid flows to the opposite side of the condenser 1 and flows back into the collecting pipes 5a-2, 5b-2 via the multitude of parallel return pipe sections 8-2. The pipe sections 8-1, 8-2 form the condensing section.As the working fluid passes through the liquefaction section, it releases heat to the environment via the air-cooled, finned pipe sections 8-1, 8-2, and thus gradually transitions from the vapor phase to a phase mixture along the cooling section and finally essentially completely into the liquid phase.

[0073] The working fluid is transported by a slight pressure difference between the inlet and outlet. However, transport can also be aided by a slight positive gradient or angle in each of the pipe sections, for example, a continuous, constant angle of +1.5°. This would mean that the starting point of an outgoing pipe section 8-1 exiting the distribution pipe 5a-1, 5b-1 would be higher than the endpoint of a return pipe section 8-2 entering the collector pipe 5a-2, 5b-2. In this case, the pipe sections 8-1, 8-2 would be installed at a downward slope in each of the finned heat exchangers 5a, 5b. For the sake of simplicity, however, any fixed positive angle of the pipe sections 8-1, 8-2 within the finned heat exchanger 5a / b will be disregarded in the following considerations.

[0074] In the collecting pipes 5a-2 and 5b-2, the individual partial flows from the pipe sections 8-1 and 8-2 are recombined and, via the outlets OUT of the collecting pipes 5a-2 and 5b-2, are combined in a common collecting tank (not shown). The collecting tank serves as an intermediate tank for supplying a steam power plant (not shown).

[0075] For the operation of the steam power plant, it is essential that the working fluid is pumpable, essentially liquid, and within a temperature range that ensures it does not evaporate, even partially, during pumping, thus preventing cavitation-induced wear in the pump. At the same time, the working fluid should be kept as cool as possible, meaning it should have the highest possible temperature, so that it can be evaporated and superheated later with minimal energy input. Against this background, an optimal target temperature for the working fluid at and / or after the outlet of condenser 1, i.e., in the collection tank, can be defined for the current operating state of the plant or for specific parameters. An additional constraint is that the steam power plant must not experience an insufficient supply of working fluid.The collection tank must not run dry. Disturbances that influence the actual temperature of the working fluid include, besides varying operating parameters of the steam power plant, especially the weather with environmental parameters such as ambient temperature, humidity, wind speed, sun position and solar radiation, etc.

[0076] To accommodate varying environmental influences and to ensure that the temperature of the working fluid closely approximates the target temperature in the collection tank, the intermediate frame 3 of the condenser 1 is rotatable, and the tilt angle α of the intermediate frame 3 is controlled by a control unit (not shown) of the condenser 1. The control unit employs a software-based control procedure that monitors the tilt angle α of the intermediate frame 3.

[0077] In Fig. 2A The condenser 1 is shown in a longitudinal view in a neutral position. In the neutral position, the intermediate frame 3 is horizontally oriented, i.e., perpendicular to gravity g. The angle of inclination α between the plane defined by the intermediate frame 3 and the axis of rotation X is therefore 0°. Accordingly, the angle of inclination α of the finned heat exchangers 5a / b, the pipe arrangements 6 (consisting of 6a / b), and the individual pipe sections 8-1 and 8-2 of the pipe arrangements 6 is also identically 0°, assuming that the pipe sections 8-1 and 8-2 run purely horizontally.

[0078] The inclination angle α of the intermediate frame 3 therefore corresponds to the inclination angle of the line sections 8-1, 8-2. The term "inclination angle" is therefore used interchangeably for both inclination angles of the intermediate frame 3 as well as the line sections 8-1, 8-2.

[0079] In one possible embodiment of a control method according to the invention, the control unit regulates the tilt angle α of the intermediate frame 3 such that the positive tilt angle α is increased to increase the flow rate of the working fluid through the pipe arrangement 6 when a measuring device detects an excessively low temperature of the working fluid in the collection tank. The increased flow rate results in an increased temperature of the working fluid in the collecting pipe 5a-2, 5b-2 and in a downstream collection tank. The control applies analogously to excessively high temperatures, in which case the positive tilt angle α is decreased. The tilt angle α is adjusted via the electric actuator 4. An increased positive tilt angle α of the intermediate frame 3 compared to the neutral position is in Fig. 3 As shown. It is expedient to define an upper and a lower fixed limit for the inclination angle α – taking into account boundary conditions – which – except in the case of leakage – is neither exceeded nor fallen below.

[0080] In another embodiment of a control method according to the invention, an optimal inclination angle α for a specific situation is retrieved from a data set stored in the control unit, which contains optimal inclination angles α for a multitude of specific situations. A specific situation can be understood as a multidimensional vector of a multitude of selected parameters or measured values ​​of the condenser 1 and its environment. The parameters or measured values ​​are continuously acquired by corresponding sensors and transmitted to the control unit, which then uses this information to determine an optimal inclination angle α from the database at predetermined intervals and adjusts the inclination angle α accordingly by actuating the actuator 4.

[0081] In the event of a sudden leak, the control device can be configured to adjust the tilt angle α – as in Fig. 4 shown - to adjust negatively so that the working fluid is retained in the line arrangement 6 (indicated by the two arrows pointing in the same direction in Fig. 4 , which symbolize the flow direction in each of the outgoing and returning pipe sections 8-1 and 8-2 respectively).

[0082] The length and width of the air fin heat exchangers 5a / b, and consequently the dimensions of the condenser 1, are expediently determined by the desired cooling capacity. The greater the required cooling capacity, the longer and / or wider the condenser 1 and its piping arrangements 6 can be, and the more fans 7 can be arranged longitudinally, one behind the other and / or parallel to each other.

[0083] It is of course also possible to connect several condensers 1 to one system, for example in a twin or star configuration, where the condensers are arranged radially from a central assembly of the system. It can be advantageous that each of the multiple condensers, and especially the tilt angle α of each condenser, is controlled independently of the others in order to adequately compensate for differing environmental conditions.

[0084] Directional references in this document such as "horizontal", "vertical", "sideways" or "top" always refer to the condenser 1 in its finished, permanently installed and operational state. Bezugszeichenliste

[0085] 1 Condenser 2 Frame 2a Longitudinal braces 2b Transverse braces 2c Vertical braces 3 Intermediate frame 3a Longitudinal braces 3b Transverse braces 4 Actuator 5a / b Fin heat exchanger (with cover plates) 5a / b-1 Distributor pipe 5a / b-2 Manifold pipe 6 Piping arrangement 7 Fan 8 Piping section 9a / b Air filter unit (synonym: filter mats) X Axis of rotation α Inclination angle E Horizontal plane

Claims

1. Air-cooled condenser (1) for condensing a working fluid, comprising a pipe arrangement (6) which extends from an inlet (EIN) to an outlet (AUS) and along which the working fluid is guided and is condensed by heat dissipation, the pipe arrangement (6) comprising at least one pipe section (8) which has an angle of inclination (α) which defines a slope with respect to a flow direction of the working fluid, characterized in that the angle of inclination (α) of the pipe section (8) is adjustable by means of an actuator (4) coupled to the pipe section (8) for adjusting the angle of inclination (α).

2. Condenser according to claim 1, characterized in that at least one pipe section (8) is rigid and extends continuously from the inlet (EIN) to the outlet (AUS).

3. Condenser according to one of the preceding claims, characterized in that the pipe arrangement (6) is an air-cooled fin-type heat exchanger (5a; 5b) with a distribution pipe (5a-1; 5b-1) arranged at the inlet and a collector pipe (5a-2; 5b-2) arranged at the outlet.

4. Condenser according to one of the preceding claims, characterized in that the at least one pipe section (8) is mounted rotatably about a horizontal (horizontal plane E) axis (X) for adjusting the slope, and wherein the angle of inclination (α) is positively and / or negatively adjustable, preferably by an angular difference of at least 2°, preferably of at least 5° or particularly preferably at least 7.5°, in the positive and / or negative direction of rotation.

5. Condenser according to one of the preceding claims, characterized in that it comprises an automatic, in particular electromotive actuator (4) for adjusting the angle of inclination (α) of the at least one pipe section (8).

6. Condenser according to one of the preceding claims, characterized in that it comprises a fan (7) for generating an airflow directed towards the pipe section (8) for cooling the pipe section (8) by forced air convection, the fan (7) being mechanically connected to the at least one pipe section (8) in such a way that the direction of flow of the airflow does not change or at least does not change significantly when the angle of inclination (α) of the pipe section (8) is changed.

7. Condenser according to one of the preceding claims, characterized in that it comprises a control device for controlling the automatic actuator (4) and sensor means for detecting at least one measuring variable of operating and / or ambient parameters of the condenser (1), such as in particular a working fluid temperature and / or an ambient temperature, a time or a time period, a wind speed or precipitation, wherein the control device is set up to control the actuator (4) on the basis of the measuring variable detected in real time or predictively for setting the angle of inclination (α) of the pipe section (8).

8. Condenser according to one of the preceding claims, characterized in that it comprises a preferably wireless communication means for bidirectional communication of the control device with an external device, such as a higher-level control center, via which external control commands can be received and forwarded to the control device for changing the angle of inclination (α) of the pipe section (8).

9. Condenser according to one of claims 3 to 9, characterized in that it comprises at least a first and a second fin-type heat exchanger (5a; 5b), each having a plurality of pipe sections (8) lying parallel in the respective fin-type heat exchanger, wherein the pipe sections (8) of the first and the second fin-type heat exchanger (5a; 5b) also run parallel, and wherein the fin-type heat exchangers (5a; 5b) are arranged in a V-shape relative to one another.

10. A steam power plant for generating energy from heat with an organic working fluid for carrying out a Rankine cycle, comprising a condenser (1) according to any of the preceding claims.

11. Control method for operating a condenser (1) according to one of claims 1 to 9, characterized in that it comprises a first control circuit for controlling the angle of inclination (α) of the at least one pipe section (8), via which the flow velocity of the working fluid flowing in the pipe section (8) along the flow direction is changed for adapting the heat transfer by changing the slope on the basis of at least one measuring variable.

12. Method according to claim 11, characterized in that a measuring variable is the temperature of the working fluid at and / or after the outlet of the condenser (1), in particular the temperature in the or a collector pipe and / or a downstream collector tank, wherein the positive angle of inclination (α) is decreased if the temperature exceeds a previously set upper threshold value or is predicted to exceed it, and wherein the positive angle of inclination (α) is increased if the temperature falls below a previously set lower threshold value or is predicted to fall below it.

13. Method according to one of claims 11 or 12, characterized in that a measuring variable is a fill level of the working fluid in an intermediate storage tank, in particular in the or a collector pipe or collector tank, and the permissible angle of inclination (α) is limited downwards and, if necessary, increased if the fill level falls below a predetermined value or is predicted to fall below a predetermined value.

14. Method according to one of claims 11 to 13, characterized in that the control method has a second control circuit for controlling the fan power of a fan (7), the second control circuit being used to control the fan power to a first fan speed on the basis of a measured pressure value which is determined at the inlet of the condenser (1) or upstream thereof or both, in particular as the output pressure of a turbine, and wherein the fan speed is increased when the angle of inclination (α) of the pipe section (8) has reached a permissible minimum value at which the cooling capacity of the condenser (1) cannot be increased by further reduction of the angle of inclination (α).

15. Method according to one of claims 11 to 14, characterized in that a change in the angle of inclination (α) takes place discontinuously over time relative to control times spaced apart from one another, so that the slope of the pipe section (8) is changed a maximum of 15 times per hour or less frequently.

16. Method according to one of claims 11 to 15, characterized in that the fluid circuit of the working fluid flowing through the condenser (1) is monitored for leakage by monitoring means, and in the event of a leakage being detected, the angle of inclination (α) is adjusted so that the slope is negative with respect to the horizontal, and the working fluid is retained in the condenser (1) in this way.

17. Method for operating a condenser (1) according to one of claims 11 to 16, wherein at least one measured value of at least one measuring variable of a process or environmental parameter of the condenser (1) is determined and a target slope for the pipe section (8) of the condenser (1) is selected from a data set on the basis of this at least one measured value, in which an associated target slope is stored for the at least one determined measured value, and the slope is set accordingly, this data set being determined by evaluating empirically collected data of process and / or environmental parameters of the condenser (1), of a system connected to the condenser (1) and / or identical or similar condensers (1) or systems, in that the empirically collected data are analyzed by means of statistical methods and / or machine learning with regard to the relationship between the existing slope of the condenser (1) concerned and a variable to be optimized, in particular a degree of energy efficiency of the condenser (1) or a system connected to the condenser (1), and correlations between the slope and the variable to be optimized were determined and stored in the data set as target slopes assigned to individual measured values.

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