METHOD FOR OPERATING A POWER HEATING ENGINE SYSTEM, CONTROL OR REGULATION DEVICE AND POWER HEATING ENGINE SYSTEM

Description

State of the art

[0001] A method for operating a combined heat and power (CHP) system has already been proposed, comprising at least one domestic hot water (DHW) and / or domestic hot water (DHW) temperature control mode for water treatment, at least one room temperature control mode for temperature control of a heating and / or cooling circuit connected to the CHP system, and a transition mode for adjusting the flow temperature of the CHP system when switching from the DHW and / or domestic hot water (DHW) temperature control mode to the room temperature control mode. Relevant prior art is described in documents EP2848870A1 and EP3594575A1. Disclosure of the invention

[0002] The invention relates to a method for operating a combined heat and power system, comprising at least one domestic hot water and / or drinking water temperature control mode for water treatment, at least one room temperature control mode for temperature control of a heating and / or cooling circuit connected to the combined heat and power system, and a transition mode for adjusting the flow temperature of the combined heat and power system when switching from the domestic hot water and / or drinking water temperature control mode to the room temperature control mode.

[0003] It is proposed that, in the transition mode, at least one heat transfer fluid delivery unit of a heat distribution unit of the combined heat and power (CHP) system is adjusted depending on at least one temperature, in particular the flow temperature, of the heat distribution unit. The CHP system preferably comprises a CHP unit. In the space heating mode, the CHP unit can preferably be used as a heat source or as a heat sink. The heat distribution unit preferably comprises a portion of a heat transfer fluid circuit for transporting heat from the CHP unit to a consumer acting as a heat sink, for example, a hot water storage tank and / or a radiator of the heating and / or cooling circuit, or from a consumer acting as a heat source, for example, a heat sink of the heating and / or cooling circuit, to the CHP unit.The terms "heat source" and "heat sink" preferably refer to a function of a component within the heat transfer circuit and, in particular, not to an external effect of the component. The heat transfer pump unit is preferably designed to circulate a heat transfer medium, especially water, in the heat transfer circuit. The heat transfer circuit preferably comprises at least one water treatment branch, a heating and / or cooling branch connected in parallel to it via a fluid connection, and at least one switching unit, in particular a three-way valve, for switching between a fluid connection between the power unit and the water treatment branch and a fluid connection between the power unit and the heating and / or cooling branch. Preferably, the power unit is fluidly coupled to the water treatment branch in the domestic hot water and / or drinking water temperature control mode.In the domestic hot water and / or drinking water temperature control mode, water, in particular process water, domestic hot water, or drinking water, is preferably tempered, and in particular heated, by means of heat transfer from the heat transfer medium in a hot water storage tank. The hot water storage tank can be designed as an instantaneous water heater, with a storage capacity of the hot water storage tank fluid-technically connected to the water treatment branch. Alternatively, the hot water storage tank is designed as a domestic hot water and / or drinking water storage tank, with the water treatment branch fluid-technically separated from the storage capacity of the hot water storage tank and routed through the hot water storage tank. Preferably, in the domestic hot water and / or drinking water temperature control mode, the heat transfer medium is heated by the heat engine, in particular to kill germs, to a flow temperature of more than 60°C.Preferably, the combined heat and power unit is fluidly coupled to the heating and / or cooling circuit in room temperature control mode. In room temperature control mode, the heating and / or cooling circuit is temperature-controlled, in particular heated or cooled, by means of the heat transfer medium, directly or indirectly, for example, via a hydraulic separator or a heat exchanger. The heating and / or cooling circuit is preferably intended for temperature control of a building, in particular of a room and / or several rooms within a building. Preferably, in room temperature control mode, a flow temperature of less than 60°C is used, particularly when radiators are used in the heating and / or cooling circuit, or less than 40°C, particularly when underfloor heating is used in the heating and / or cooling circuit.

[0004] The combined heat and power (CHP) system preferably comprises at least one control device for implementing the transition mode. In a process step of the transition mode, the control device preferably switches the switching unit to decouple the water treatment branch from the CHP unit and couple the heating and / or cooling branch to the CHP unit. In the transition mode, the control device preferably adjusts the heat transfer fluid delivery unit to control the flow temperature and, in particular, to reduce it relative to a specific flow temperature value during the domestic hot water (DHW) temperature control mode. Preferably, the heat transfer fluid delivery unit is speed-controlled, with the control device specifying a target speed. Alternatively, the control device sets a flow rate of the heat transfer fluid delivery unit by switching it on and off, and also sets a utilization rate of the heat transfer fluid delivery unit.Preferably, at least one flow temperature sensor of the combined heat and power system detects the flow temperature. Optionally, at least one buffer temperature sensor detects the buffer temperature of the hydraulic separator. Preferably, in transition mode, the control device adjusts the heat transfer fluid delivery unit depending on the flow temperature and optionally also depending on the buffer temperature. Particularly preferably, in transition mode, the control device reduces the delivery rate of the heat transfer fluid delivery unit relative to that of the domestic hot water and / or drinking water temperature control mode, especially to minimize heat transfer from the heat transfer fluid to the heating and / or cooling circuit. Preferably, the control device only starts the room temperature control mode when the flow temperature falls below a predetermined threshold.

[0005] The design according to the invention advantageously minimizes the risk of exceeding a permissible flow temperature for the heating and / or cooling circuit. In particular, when operating in a cooling mode as room temperature control, the heating of the heating and / or cooling circuit by the heat transfer medium can be advantageously minimized, thus maintaining a high level of user comfort. Similarly, when operating in a heating mode as room temperature control, the risk of damage to the heating and / or cooling circuit due to excessive heat input can be advantageously minimized.

[0006] It is further proposed that when switching from domestic hot water and / or drinking water temperature control mode to a cooling mode as room temperature control mode, the switch from a water treatment circuit to the heating and / or cooling circuit is delayed at least until the flow temperature drops. The water treatment circuit includes, in particular, the water treatment branch and the hot water storage tank. The switch is preferably carried out by the switching unit. Hereinafter, "in at least one process step of the transition mode when switching to the cooling mode as room temperature control mode" is referred to simply as "in the cooling transition mode." In the cooling transition mode, the control device preferably controls the switching unit depending on at least one measured value of the flow temperature.In the cooling transition mode, the control device preferably switches the heat engine from heating to cooling operation, for example, by means of a four-way valve in a refrigerant circuit of the heat engine. In the cooling transition mode, the control device preferably switches the heat engine, in particular a compressor of the heat engine, to high-performance operation. In high-performance operation, the heat engine, in particular the compressor, delivers more than 50%, preferably more than 60%, most preferably more than 75%, optionally 100%, of the rated power of the heat engine. Optionally, the power output of the heat engine in high-performance operation depends on a starting measurement of the flow temperature at the initiation of the cooling transition mode. Alternatively, the power output of the heat engine in high-performance operation is set independently of the measured value of the flow temperature.Preferably, a measuring point for the flow temperature is arranged within the heat distribution unit and, in particular, at a distance from the power plant, especially from a heat exchanger of the power plant that thermally couples the power plant to the heat transfer fluid circuit. Particularly in the case of an outdoor installation of the power plant, a distance of more than 10 meters, more than 20 meters, or more than 30 meters between the power plant and the measuring point is possible in some configurations of the power plant system. Preferably, the switching unit is only activated when a temperature drop is detected at the measuring point within the heat distribution unit.Optionally, the control device compares the measured value at the measuring point within the heat distribution unit with another measured value of the flow temperature at an output of the heat engine and actuates the switching unit if the difference between the measured values ​​falls below a tolerance value. Alternatively, the control device actuates the switching unit if the measured value at the measuring point within the heat distribution unit falls below a predefined threshold value and / or exhibits a predefined minimum difference from the initial measured value. Optionally, the control device determines a delay time with which the switching unit is actuated after the drop in flow temperature is detected, particularly depending on the flow rate of the heat transfer fluid supply unit and the distance of the measuring point from a branch of the heat transfer fluid circuit into the water treatment branch and the heating and / or cooling branch.Alternatively, the control device actuates the switching unit immediately after detecting a drop in the flow temperature. The design according to the invention allows an advantageously large proportion of the still-heated heat transfer fluid to be routed through the water treatment circuit before switching to the heating and / or cooling circuit. Furthermore, the cooling of the water treatment circuit by the incoming cooled heat transfer fluid can be advantageously minimized.

[0007] It is further proposed that in at least one process step, when switching from the domestic hot water and / or drinking water temperature control mode to a cooling mode (room temperature control mode), the flow rate of the heat transfer fluid delivery unit is reduced relative to the domestic hot water and / or drinking water temperature control mode. Preferably, the flow rate in the cooling transition mode is reduced to less than 50% of a maximum flow rate, more preferably to less than 25% of a maximum flow rate, and most preferably to a minimum value. The design according to the invention allows for advantageously rapid cooling of the heat transfer fluid at the heat engine.Furthermore, the spatial distance between the relatively hot and relatively cold heat transfer fluids within the supply line of the heat transfer circuit can be advantageously kept small, so that a cold front forms within the supply line, which is pushed towards the distribution unit by the relatively low flow rate. A beneficially abrupt drop in the supply temperature can be detected at the measuring point. The switching unit can be advantageously switched precisely, in particular so that a beneficially large proportion of the still relatively hot heat transfer fluid flows into the water treatment circuit and a beneficially large proportion of the relatively cold heat transfer fluid flows into the heating and / or cooling circuit.

[0008] Furthermore, it is proposed that in at least one process step, during a switch from the domestic hot water and / or drinking water temperature control mode to a cooling mode, a power unit, in particular the one already mentioned, of the power unit system is operated in a high-performance mode, in particular the one already mentioned. Due to the design according to the invention, the heat transfer medium can be advantageously cooled quickly in the cooling transition mode.

[0009] It is further proposed that, in at least one process step, when switching from domestic hot water and / or drinking water temperature control mode to a cooling mode (room temperature control mode), the flow rate of the heat transfer fluid delivery unit is controlled as a function of the heat exchanger temperature of one of the aforementioned power plants within the power plant system. The heat exchanger temperature is preferably measured at an outlet of the power plant and optionally extrapolated to a temperature within the heat exchanger. The control device adjusts the flow rate of the heat transfer fluid delivery unit, preferably as a function of the heat exchanger temperature. Preferably, the control device adjusts the flow rate of the heat transfer fluid delivery unit such that the heat exchanger temperature, particularly the temperature within the heat exchanger, remains above a certain limit.The limit value is preferably more than 15°C, more preferably more than 20°C, and particularly preferably 25°C. Particularly preferably, the control device sets the flow rate to the lowest possible value at which the limit value of the heat exchanger temperature can be maintained. Due to the design according to the invention, the risk of ice formation on and / or in the heat exchanger can be advantageously kept low in the cooling transfer mode.

[0010] It is further proposed that, in at least one process step of the process, when switching from domestic hot water and / or drinking water temperature control mode to a heating mode (room temperature control mode), the heat transfer fluid delivery unit is controlled as a function of a buffer temperature, in particular the one already mentioned. Hereafter, "in at least one process step of the transition mode when switching to the heating mode (room temperature control mode)" is referred to simply as "in the heating transition mode." In the heating transition mode, the heat transfer fluid delivery unit is preferably controlled by the control device such that the buffer temperature remains below a permissible maximum value of the flow temperature. Preferably, the control device controls the heat transfer fluid delivery unit as a function of a setpoint for the flow temperature. The setpoint is, for example, specified by a user or an external building control system.Preferably, the control device attempts to adjust the measured flow temperature to the setpoint, particularly without the buffer temperature exceeding the permissible maximum value. Preferably, the control device prioritizes adherence to the permissible maximum value over adjustment to the setpoint. Preferably, the control unit reduces the flow rate of the heat transfer fluid delivery unit, and in particular the flow temperature, when the buffer temperature is less than a minimum distance from the permissible maximum value. Preferably, the control unit increases the flow rate of the heat transfer fluid delivery unit, and in particular the flow temperature, when the buffer temperature is more than a minimum distance from the permissible maximum value.The design according to the invention advantageously minimizes the risk of exceeding the permissible maximum flow temperature. Furthermore, adherence to the setpoint can be reliably achieved despite limitations during the changeover. A high level of comfort can be attained.

[0011] It is further proposed that in at least one process step, when switching from domestic hot water and / or drinking water temperature control mode to a heating mode (room temperature control mode), a power unit, in particular the one already mentioned, of the power unit system is switched off until the temperature, in particular the buffer temperature and / or the flow temperature, falls below a threshold value. Preferably, the compressor of the power unit is switched off. Preferably, the power unit, in particular the compressor, is reactivated when the measured value of the flow temperature falls below the setpoint, optionally less a hysteresis factor. Preferably, the power unit is switched off at the beginning of the heating transition mode and remains switched off for the duration of the heating transition mode.Preferably, the control device switches the combined heat and power (CHP) engine off and on at most once during the heating transition mode. Alternatively, instead of completely switching off the CHP engine, it continues to operate at minimum power during the heating transition mode. Optionally, depending on a starting measurement of the flow temperature at the initiation of the heating transition mode, the control device selects whether the CHP engine is completely switched off or continues to operate at minimum power. The design according to the invention allows the heat present in the heat transfer fluid circuit to be advantageously utilized before the CHP engine needs to be activated.The number of start-up cycles of the heat engine, particularly the compressor, can be advantageously kept low, and the service life of the heat engine, particularly the compressor, can be advantageously kept high. According to the invention, it is defined that in at least one process step, during a change from the domestic hot water and / or drinking water temperature control mode to a heating mode (room temperature control mode), the flow rate of the heat transfer fluid delivery unit exhibits a sawtooth-like time profile, which is formed by reaching threshold values ​​and / or limit values ​​of the temperature. Preferably, an increase in the flow rate of the heat transfer fluid delivery unit has a smaller step size per unit of time than a decrease in the flow rate. Particularly preferably, the flow rate is set to a minimum value with a maximum rate of change during a decrease.The minimum flow rate can be zero or a non-zero value. The maximum rate of change is limited, for example, and in particular only, by a moment of inertia, motor power, and / or the control of the heat transfer fluid delivery unit. Preferably, the maximum rate of change is greater than 1% / s, more preferably greater than 5% / s, and most preferably greater than or equal to 10% / s, where percentages refer to the maximum flow rate of the heat transfer fluid delivery unit. An increase in the flow rate preferably occurs at a rate of change that is at least twice, more preferably at least three times, and most preferably at least five times slower than the maximum rate of change.Particularly preferably, in the heating transition mode, the flow rate is increased at a rate of change of less than 1% / s, preferably less than 0.5% / s, particularly preferably less than 0.1% / s, and most preferably less than 0.085% / s, where percentages refer to the maximum flow rate of the heat transfer fluid delivery unit. Preferably, the control device sets the flow rate to the minimum value at the beginning of the heating transition mode. Preferably, the control device increases the flow rate until the buffer temperature reaches a holding threshold. Preferably, the control device maintains the flow rate constant when the buffer temperature exceeds the holding threshold. Preferably, the control device reduces the flow rate, particularly to the minimum value, when the buffer temperature reaches a shutdown limit.Preferably, the control device increases the flow rate when the buffer temperature falls to a restart threshold. The shutdown threshold is preferably higher than the holding threshold. The restart threshold is preferably lower than the holding threshold. The shutdown threshold is preferably less than or equal to the permissible maximum flow temperature. The holding threshold, the shutdown threshold, and / or the restart threshold can be predefined or variable, for example, depending on the setpoint of the flow temperature and / or a hysteresis of the heat transfer fluid circuit. According to the invention, heat present in the heat transfer fluid circuit can be gradually transferred to the heating and / or cooling circuit without exceeding the permissible maximum flow temperature.Furthermore, the amplitude of a sudden increase in the volume flow of the heat transfer fluid can be advantageously kept small when using check valves in the heat transfer fluid circuit.

[0012] It is further proposed that in at least one process step, when switching from domestic hot water and / or drinking water temperature control mode to a heating mode (room temperature control mode), the flow rate of the heat transfer fluid delivery unit is kept constant when a temperature threshold, particularly the buffer temperature, is exceeded, especially when the aforementioned holding threshold is exceeded. The design according to the invention advantageously minimizes the risk of the buffer temperature exceeding the permissible maximum flow temperature.

[0013] Furthermore, a control device for carrying out a method according to the invention is proposed. A "control device" is understood to mean, in particular, a unit with at least one control electronics unit. A "control electronics unit" is understood to mean, in particular, a unit with a processor unit and a memory unit, as well as an operating program stored in the memory unit. The design according to the invention allows a combined heat and power system to be operated with advantageously high user comfort and / or advantageously with low wear.

[0014] Furthermore, a combined heat and power (CHP) system is proposed, comprising at least one CHP unit, in particular one of the types already mentioned, at least one heat distribution unit, and at least one control device according to the invention. The CHP unit is preferably designed as a compression CHP unit, in particular as an air-to-water heat pump. Preferably, the CHP unit comprises the refrigerant circuit with the compressor, a condenser, an expansion element, and an evaporator. The CHP unit preferably includes at least one actuating element, in particular a four-way valve, for switching between heating and cooling operation. The CHP unit preferably includes the heat exchanger connected to the heat transfer fluid circuit, which functions as the aforementioned evaporator in cooling operation and as the aforementioned condenser in heating operation.The heat engine is preferably arranged in a housing designed to protect it from the elements. The heat engine is particularly intended for outdoor installation.

[0015] The heat distribution unit is preferably arranged at a distance from the power plant and is particularly intended for installation inside a building. The heat distribution unit is fluidly connected to the power plant, preferably via heat transfer lines. The heat transfer lines are preferably fluidly connected to the heat exchanger of the power plant. The heat exchanger and the heat transfer lines preferably form part of the heat transfer circuit. The heat distribution unit preferably comprises the water treatment branch and the heating and / or cooling branch of the heat transfer circuit. Optionally, the heat distribution unit includes the hot water tank. Alternatively, the water treatment branch includes connections for an external hot water tank. Optionally, the heat distribution unit includes the hydraulic separator.Alternatively, the heating and / or cooling branch includes connections to an external hydraulic separator or to a direct connection of the heating and / or cooling circuit to the heat transfer fluid circuit. The heat distribution unit preferably includes the heat transfer fluid delivery unit. The heat transfer fluid delivery unit is preferably designed as a pump. The heat distribution unit preferably includes the switching unit. The switching unit is preferably designed as a single three-way valve. Alternatively, the switching unit includes several shut-off valves.

[0016] The combined heat and power (CHP) system preferably includes a sensor unit for temperature measurement. Preferably, the sensor unit includes at least one flow temperature sensor element in the heat distribution unit for measuring the flow temperature. Preferably, the sensor unit includes at least one buffer temperature sensor element on or in the hydraulic separator for measuring the buffer temperature. Preferably, the sensor unit includes at least one heat exchanger temperature sensor element at an outlet of the CHP system for measuring the heat exchanger temperature.

[0017] The design according to the invention allows the transition mode to be advantageously implemented without additional components, such as a bypass valve. In particular, a combined heat and power system with a transition mode can be manufactured with advantageously small installation space and / or at advantageously low costs.

[0018] The inventive method, the inventive control device, and / or the inventive heat engine system are not / should not be limited to the application and embodiment described above. In particular, the inventive method, the inventive control device, and / or the inventive heat engine system may, to achieve a functionality described herein, comprise a different number of individual elements, components, units, and process steps than that specified herein. Furthermore, values ​​within the specified limits of the value ranges stated in this disclosure shall also be considered disclosed and freely usable. Drawings

[0019] Further advantages become apparent from the following description of the drawings. The drawings illustrate two exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0020] They show: Fig. 1 a schematic representation of a combined heat and power system according to the invention, Fig. 2 a schematic flow diagram of a method according to the invention, Fig. 3 a schematic time profile of a delivery rate of a heat transfer fluid delivery unit in the course of the method according to the invention and Fig. 4 a schematic representation of an alternative embodiment of a combined heat and power system according to the invention. Description of the exemplary implementations

[0021] Figure 1Figure 1 shows a combined heat and power (CHP) system 12a. The CHP system 12a comprises at least one CHP unit 28a. The CHP system 12a comprises at least one heat distribution unit 22a. The CHP system 12a comprises at least one control device 34a. The control device 34a is provided for carrying out a method 10a, which is described in Figure 2 will be explained in more detail.

[0022] The combined heat and power (CHP) engine 28a preferably comprises a refrigerant circuit 36a. As part of the refrigerant circuit 36a, the CHP engine 28a preferably includes at least one heat exchanger 40a. The heat exchanger 40a thermally couples the refrigerant circuit 36a to a heat transfer circuit 42a of the CHP system 12a. The CHP engine 28a is connected to the heat distribution unit 22a via heat transfer lines, specifically via at least one supply line 46a and at least one return line 44a, of the heat transfer circuit 42a.

[0023] The combined heat and power (CHP) engine 28a preferably comprises a control unit 38a for adjusting the refrigerant circuit 36a, in particular a compressor of the refrigerant circuit 36a. The CHP engine 28a preferably comprises a housing in which the refrigerant circuit 36a and / or the control unit 38a are arranged. The CHP engine 28a preferably has at least one data interface for data exchange between the control unit 38a and the control device 34a. The data interface is preferably an interface of a bus system, for example a Controller Area Network (CAN bus) interface. Preferably, the CHP system 12a comprises at least one heat exchanger temperature sensor element 48a, which is preferably arranged at a flow outlet of the heat exchanger 40a.

[0024] The heat distribution unit 22a preferably comprises a water treatment branch 50a of the heat transfer fluid circuit 42a. The heat distribution unit 22a preferably comprises a heating and / or cooling branch 52a of the heat transfer fluid circuit 42a. The water treatment branch 50a and the heating and / or cooling branch 52a are preferably connected in parallel to the supply line 46a via fluid connections. The heat distribution unit 22a preferably comprises at least one switching unit 54a to selectively couple either the water treatment branch 50a or the heating and / or cooling branch 52a to the heat exchanger 40a via fluid connections. Preferably, the heat distribution unit 22a comprises a heat transfer fluid pumping unit 20a for circulating the heat transfer fluid through the heat transfer fluid circuit 42a.The heat transfer fluid delivery unit 20a is preferably arranged in the common return line 44a of the water treatment branch 50a and the heating and / or cooling branch 52a to the heat engine 28a, particularly downstream of the switching unit 54a. The heat engine system 12a preferably comprises a flow temperature sensor element 66a arranged in the heat distribution unit 22a on the flow line 46a for detecting the flow temperature of the heat transfer fluid. Preferably, the flow temperature sensor element 66a is arranged downstream of the heat exchanger temperature sensor element 48, particularly downstream of an electric auxiliary heater 68a of the heat distribution unit 22a. Preferably, the flow temperature sensor element 66a is arranged downstream of a branch of the heat transfer fluid circuit 42a into the water treatment branch 50a and the heating and / or cooling branch 52a.The heat transfer unit 20a is preferably connected to the control device 34a via data transmission, for example via a Local Interconnect Network (LIN bus) interface. The heat distribution unit 22a preferably includes a user interface 56a, in particular for specifying a desired hot water temperature and / or a desired room temperature.

[0025] The water treatment branch 50a preferably runs through a hot water storage tank 58a of the combined heat and power system 12a for the purpose of tempering water in the hot water storage tank 58a. The combined heat and power system 12a preferably includes a water temperature sensor element 60a, which is arranged on or in the hot water storage tank 58a, for detecting the water temperature of the water contained in the hot water storage tank 58a.

[0026] The heating and / or cooling branch 52 is preferably connected to a hydraulic separator 62a of the combined heat and power (CHP) system 12a. The hydraulic separator 62a is preferably designed to thermally couple a heating and / or cooling circuit 18a with the heat transfer fluid circuit 42a. The CHP system preferably includes at least one buffer temperature sensor element 64a in or on the hydraulic separator 62a for detecting a buffer temperature of the heat transfer fluid located in or flowing into the hydraulic separator 62a. The heating and / or cooling circuit 18a particularly includes a further heat transfer fluid conveying unit and forms a further heat transfer fluid circuit that is hydraulically decoupled from the heat transfer fluid circuit 42a.

[0027] Figure 2Figure 1 shows a flowchart of method 10a for operating the combined heat and power system 12a. Method 10a comprises at least one domestic hot water and / or drinking water temperature control mode 14a for water treatment. In domestic hot water and / or drinking water temperature control mode 14a, the control device 34a switches the switching unit 54a to the water treatment branch 50a and the combined heat and power engine 28a to heating mode in order to heat water in the hot water storage tank 58a. Preferably, the control device 34a terminates domestic hot water and / or drinking water temperature control mode 14a when the water temperature sensor element 60a, which is preferably located at half the fill level of the hot water storage tank 58a, detects a water temperature above a threshold value, for example, 60°C. In domestic hot water and / or drinking water temperature control mode 14a, the heat transfer fluid delivery unit 20a is preferably switched on and the other heat transfer fluid delivery unit is preferably switched off.

[0028] Method 10a comprises at least one room temperature control mode, namely at least one heating mode 30a and / or one cooling mode 24a, for temperature control of the heating and / or cooling circuit 18a connected to the combined heat and power system 12a. In heating mode 30a, the combined heat and power system 28a preferably operates in heating mode. In cooling mode 24a, the combined heat and power system 28a preferably operates in cooling mode. In heating mode 30a and cooling mode 24a, the switching unit 54a is preferably set to the heating and / or cooling branch 52a.

[0029] Method 10a comprises a transition mode for adjusting the flow temperature of the combined heat and power system 12a when switching from domestic hot water and / or drinking water temperature control mode 14a to one of the room temperature control modes. When transitioning to cooling mode 24a, Method 10a includes a cooling transition mode. When transitioning to heating mode 30a, Method 10a includes a heating transition mode. Method 10a preferably includes a temperature control demand determination 70a. The temperature control demand determination 70a is preferably performed after the domestic hot water and / or drinking water temperature control mode 14 has ended. In the temperature control demand determination 70a, the control device 34a preferably determines whether there is a heating or cooling demand. In the temperature control demand determination 70a, the control device 34a preferably activates the additional heat transfer fluid delivery unit.In the temperature control demand determination 70a, the control device 34a preferably evaluates a measured value of the buffer temperature to detect a heating or cooling demand. If the measured value of the buffer temperature is above a setpoint of the flow temperature, particularly taking into account a hysteresis of the heating and / or cooling circuit 18a, the control device 34a preferably concludes that there is a cooling demand, particularly taking into account an outside temperature outside a building to be cooled by the combined heat and power system. If the measured value of the buffer temperature is below a setpoint of the flow temperature, particularly taking into account a hysteresis of the heating and / or cooling circuit 18a, the control device 34a preferably concludes that there is a heating demand, particularly taking into account an outside temperature outside a building to be heated by the combined heat and power system.The control device 34a determines the setpoint of the flow temperature, for example, based on the desired room temperature specified via the user interface 56a. If there is a cooling requirement, the control device 34a preferably operates in cooling transition mode. If there is a heating requirement, the control device 34a preferably operates in heating transition mode.

[0030] The cooling transition mode preferably comprises a power engine conversion step 72a. In the power engine conversion step 72a, the control device 34a preferably causes the power engine 28a to switch to cooling mode. Preferably, the control device 34a sets the power engine 28a to high-performance operation in cooling mode.

[0031] The cooling transition mode preferably includes a flow rate adjustment step 74a. In the flow rate adjustment step 74a, a flow rate 16a (see Fig. 3 The flow rate of the heat transfer fluid delivery unit 20a is reduced relative to the domestic hot water and / or drinking water temperature control mode 14a. The control device 34a particularly preferably sets the flow rate 16a to the lowest possible value. The control device 34a determines the lowest possible value of the flow rate 16a as a function of the heat exchanger temperature of the power unit 28a. Preferably, the control device 34a sets the flow rate 16a such that the heat exchanger temperature remains at least above a minimum temperature, in particular 30°C, at the lowest possible flow rate 16a. The heat transfer fluid delivery unit 20a is particularly preferably speed-controlled, and the flow rate 16a is a speed of the heat transfer fluid delivery unit 20a.

[0032] The cooling transition mode preferably includes a cold front detection step 76a. Preferably, the flow rate 16a is set so low and the cooling capacity of the heat engine 28a so high that a cold front forms in the heat transfer fluid at an outlet of the heat engine 28a, which is pushed towards the heat distribution unit 22a according to the flow rate 16a. For example, the heat transfer fluid has a temperature gradient of more than 10 K / m across the cold front. In the cold front detection step 76a, the control device 34a waits for the cold front to be detected at the flow temperature sensor element 66a within the heat distribution unit 22a.

[0033] The cooling transition mode preferably includes a switching step 78a. In the cooling transition mode, the switch from the water treatment branch 50a to the heating and / or cooling branch 52a is delayed at least until the flow temperature drops. Preferably, the control device 34a executes the switching step 78a when the passage of the cold front is detected by the flow temperature sensor element 66a. Optionally, after detecting the cold front, the control device 34a waits a predetermined delay time before executing the switching step 78a, the delay time depending on the distance of the flow temperature sensor element 66a from the branch of the heat transfer circuit 42a into the water treatment branch 50a and the heating and / or cooling branch 52a, and on the flow rate 16a.The delay time can be implemented by the control device 34a using a timer or a signal delay element. In the switching step 78a, the control device 34a preferably controls the switching unit 54a to perform the switch from the water treatment branch 50a to the heating and / or cooling branch 52a.

[0034] Once the changeover step 78a is completed, the control or regulating device 34a switches to cooling mode 24a, in which the control or regulating device 34a sets the flow temperature preferably according to a conventional method, in particular depending on a control difference between actual value and setpoint of a room temperature.

[0035] At the start of the heating transition mode, the control device 34a preferably activates the switching unit 54a to switch from the water treatment branch 50a to the heating and / or cooling branch 52a. The heating transition mode preferably includes a flow temperature determination 80a. If, during the flow temperature determination 80a, the flow temperature and the heat exchanger temperature are lower than the setpoint flow temperature, the control device 34a switches to heating mode 30a. If, during the flow temperature determination 80a, the flow temperature or the heat exchanger temperature is higher than the setpoint flow temperature, the control device 34a preferably switches off the combined heat and power unit 28a and sets the heat transfer fluid delivery unit 20a to a minimum value 96a of the delivery rate 16a.

[0036] In the heating transition mode, the heat transfer fluid delivery unit 20a is controlled depending on the buffer temperature. In the heating transition mode, the delivery rate 16a of the heat transfer fluid delivery unit 20a exhibits a sawtooth-like time profile 32a (see figure). Fig. 3 ), which is formed by reaching threshold values ​​and / or limit values ​​of the buffer temperature.

[0037] The heating transition mode preferably includes a flow rate increase step 82a. In the flow rate increase step 82a, the control device 34a increases the flow rate 16a continuously or stepwise. The heating transition mode preferably includes a holding threshold check 86a. In the holding threshold check 86a, the control device 34a compares an actual value of the buffer temperature with a holding threshold that is lower than a permissible maximum value of the flow temperature. If the buffer temperature is lower than the holding threshold, the control device 34a continues the flow rate increase step 82a.

[0038] The heating transition mode preferably includes a flow rate maintenance step 88a. The control device 34a executes the flow rate maintenance step 88a when the buffer temperature reaches the maintenance threshold. In the flow rate maintenance step 88a, the flow rate 16a of the heat transfer fluid delivery unit 20a is kept constant by the control device 34a. The heating transition mode preferably includes a shutdown limit monitoring 90a. In the shutdown limit monitoring 90a, the control device 34a preferably compares the buffer temperature with a shutdown limit that is less than or equal to the permissible maximum value of the flow temperature and greater than the maintenance threshold. If the buffer temperature is less than the shutdown limit, the control device 34a continues the flow rate maintenance step 88a.

[0039] The heating transition mode preferably includes a flow rate reduction step 92a. The control device 34a executes the flow rate reduction step 92a when the buffer temperature reaches the shutdown threshold. In the flow rate reduction step 92a, the control device 34a preferably sets the flow rate 16a to the minimum value 96a. The heating transition mode preferably includes a restart check 94a. Preferably, in the restart check 94a, the control device 34a compares the buffer temperature with a restart threshold, which is preferably lower than the holding threshold. If the buffer temperature is higher than the restart threshold, the control device 34a preferably continues the flow rate reduction step 92a.If the buffer temperature is equal to or less than the resumption limit, the control device 34a preferably starts again with the flow rate increase step 82a.

[0040] The heating transition mode preferably includes a cooling termination check 84a. In the cooling termination check 84a, the control device 34a preferably compares the actual value of the buffer temperature with a termination threshold. The termination threshold is preferably equal to the setpoint of the flow temperature minus a hysteresis factor. If the buffer temperature is greater than the termination threshold, the control device 34a preferably continues the heating transition mode. If the buffer temperature is less than or equal to the termination threshold, the control device 34a switches the heat engine 28a back on and preferably switches to the heating mode 30a. In the heating mode 30a, the control device 34a preferably sets the flow temperature according to a conventional method, in particular as a function of a control difference between the actual value and the setpoint of the room temperature.

[0041] In Figure 3 The flow rate 16a is plotted against time 98a as an example. The time profile 32a is preferably sawtooth-shaped, with relatively long rise times starting from the minimum value 96a of the flow rate 16a and relatively short fall times when the cut-off limit is reached due to the buffer temperature.

[0042] In the Figure 4 A further embodiment of the invention is shown. The following descriptions and drawings are essentially limited to the differences between the embodiments, whereby, with regard to identically designated components, in particular with regard to components with the same reference numerals, reference is also generally made to the drawings and / or the description of the other embodiment, i.e., the Figures 1 to 3 , can be referenced. To distinguish the embodiments, the letter a is the reference numeral of the embodiment in the Figures 1 to 3recreated. In the exemplary embodiment of the Figure 4 The letter a is replaced by the letter b.

[0043] Figure 4 Figure 1 shows a combined heat and power (CHP) system 12b. The CHP system 12b comprises at least one CHP unit 28b. The CHP system 12b comprises at least one heat distribution unit 22b. The CHP system 12b comprises at least one control device 34b. A heating and / or cooling circuit 18b is directly connected, in particular without a hydraulic separator or the like, to a heat transfer circuit 42b of the CHP system 12b. In particular, the heat transfer circuit 42b and the heating and / or cooling circuit 18b are hydraulically coupled in at least one setting of a switching unit 54b of the heat distribution unit 22b.

[0044] Regarding further features of the combined heat and power system 12b, particular attention should be paid to the Figure 1 and their descriptions are referenced.

Claims

1. Method for operating a heat engine system, with at least one service-water and / or drinking-water temperature control mode (14a) for preparing water, with at least one room-temperature control mode for controlling the temperature of a heating and / or cooling circuit (18a; 18b) connected to the heat engine system and with a transition mode for adapting a flow temperature of the heat engine system when there is a change from the service-water and / or drinking-water temperature control mode (14a) to the room-temperature control mode, wherein, in the transition mode, at least one heat-transfer fluid delivery unit (20a; 20b) of a heat distribution unit (22a; 22b) of the heat engine system is set in dependence on at least one temperature, in particular the flow temperature, of the heat distribution unit (22a; 22b), characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a heating mode (30a) as the room-temperature control mode, a delivery rate (16a) of the heat-transfer fluid delivery unit (20a; 20b) has a sawtooth-like variation over time (32a), which is formed by reaching threshold values and / or limit values of the temperature, wherein an increase in the delivery rate of the heat-transfer fluid delivery unit has a smaller increment per unit of time then a decrease in the delivery rate.

2. Method according to Claim 1, characterized in that, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a cooling mode (24a) as the room-temperature control mode, a change from a water-preparing circuit to the heating and / or cooling circuit (18a; 18b) is delayed at least until there is drop in the flow temperature.

3. Method according to Claim 1 or 2, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a cooling mode (24a) as the room-temperature control mode, a delivery rate (16a) of the heat-transfer fluid delivery unit (20a; 20b) is reduced in relation to the service-water and / or drinking-water temperature control mode (14a).

4. Method according to one of the preceding claims, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a cooling mode (24a), a heat engine (28a; 28b) of the heat engine system is operated in a high-power operating mode.

5. Method according to one of the preceding claims, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a cooling mode (24a) as the room-temperature control mode, a delivery rate (16a) of the heat-transfer fluid delivery unit (20a; 20b) is controlled in a closed-loop manner in dependence on a heat exchanger temperature of a heat engine (28a; 28b) of the heat engine system.

6. Method according to one of the preceding claims, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a heating mode (30a) as the room-temperature control mode, the heat-transfer fluid delivery unit (20a; 20b) is controlled in a closed-loop manner in dependence on a buffer temperature.

7. Method according to one of the preceding claims, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a heating mode (30a) as the room-temperature control mode, a heat engine (28a; 28b) of the heat engine system is switched off until the temperature goes below a threshold value.

8. Method according to one of the preceding claims, characterized in that, in at least one method step, when there is a change from the service-water and / or drinking-water temperature control mode (14a) to a heating mode (30a) as the room-temperature control mode, a delivery rate (16a) of the heat-transfer fluid delivery unit (20a; 20b) is kept constant when the temperature goes above a threshold value.

9. Open-loop or closed-loop control device designed for carrying out a method for operating a heat engine system, comprising at least one heat distribution unit (22a; 22b) and at least one heat-transfer fluid delivery unit (20a; 20b), according to one of the preceding claims.

10. Heat engine system with at least one heat engine (28a; 28b), with at least one heat distribution unit (22a; 22b), with at least one heat-transfer fluid delivery unit (20a; 20b) and with at least one open-loop or closed-loop control device according to Claim 9.