EP2896900B1 - Method for controlling a refrigeration or heat output for a heat/refrigeration system with multiple sources and controller for executing the method - Google Patents

Description

The invention relates to a method for controlling a cooling or heating output according to patent claim 1 and a control device for carrying out the method according to patent claim 13.

State of the art

In the state of the art it is known to use various heat sinks, e.g.

to forward different temperature requirements to a control unit for different rooms in a building. The control unit determines an operating parameter for the heat source or cold source and controls the source accordingly so that the heat sink is supplied with the desired heat or cold output. In modern heating and cooling systems for supplying rooms with heat or cold output, different heat sources or cold sources are used to generate the heat or cold output. For example, a heating system can have a solar system, a heat pump, a gas boiler or an electric heater as a heat source. In previous systems, the heat sources were controlled independently of one another in order to provide the heat or cold output required for the heat sinks.

Out of US 2007/0044501 A1 and EP 2615385 A1 Methods for controlling a cooling or heat output for a heating/cooling system with multiple sources are known, wherein in a first step a request from the at least one heat sink for a heat output or cooling output is detected, wherein in a second step at least one boundary condition of the at least one source is detected, and wherein in a third step an operating state of at least one source is determined depending on a strategy.

disclosure of the invention

The object of the invention is to provide an improved method for operating a heating/cooling system with at least one source for supplying at least one heat sink with the desired heating output or cooling output.

The object of the invention is achieved by the method according to patent claim 1 and by the control device according to patent claim 13. Further advantageous embodiments are specified in the dependent claims.

An advantage of the method described is that sources are used according to their boundary conditions and depending on a selectable strategy in such a way that the heat sinks are supplied with a heat output and/or a cooling output. In a first step, a request from the heat sinks is recorded, in a second step at least one boundary condition of the at least one source is recorded and in a third step an operating state of at least one of the sources is determined depending on the strategy in order to supply the heat sink with a cooling or heat output. Preferably, boundary conditions of at least two sources are recorded in the second step and taken into account in the third step in order to determine the operating state of at least one source depending on the strategy.

In the second step, the operating state of at least one source is recorded as whether the source is in heating mode or cooling mode, and in the third step, depending on the boundary conditions of the sources and the operating state of the source, a decision is made as to whether the operating state of the source is changed. This allows an optimal adjustment of the operating state of the source(s) to be achieved in order to supply the heat sink with the desired heating or cooling output.

According to the present invention, the desired strategy is to provide the heat and/or cooling output, for example, cost-effectively and/or efficiently and/or with low emissions and/or with high comfort and/or as quickly as possible. For example, diagrams, characteristics or formulas are stored that describe the operation of the sources depending on the desired strategy. By comparing the diagrams, characteristics and formulas, it can be determined which of the sources can best deliver which heat and/or cooling output according to the desired strategy. For example, it can be advantageous to provide the heat or cooling output supplied by a heat sink up to a desired temperature from the first source and above the desired temperature from a second source. In addition, it can be advantageous to have a short-term and rapid supply of the heat sink with the desired cooling and/or heat output from a first source and then a longer-term supply of the heat sink with a cooling and/or heat output from a second source. In a further embodiment, two or more heat sinks can also be provided, which are supplied with cooling and/or heating power from one or more heat sources. Depending on the boundary conditions of the sources and regardless of the requests and boundary conditions of the heat sinks, it can be advantageous, for example, to supply one heat sink with a heating power from one source and the other heat sink with a heating power from another source. In addition, if one heat sink requires a heating power and the other heat sink requires a cooling power, it can be advantageous, for example, to supply both heat sinks with a source with heating or cooling power. In addition, it can also be advantageous to supply both heat sinks with the heating or cooling power from different sources. One advantage of the method described is that the capabilities of the individual sources are used optimally according to the desired strategy, depending on the requests and boundary conditions of the heat sinks or the heat sink.

According to the invention, a characteristic curve and/or a characteristic field and/or a formula for the provision of the cooling and/or heating output depending on at least one parameter are provided as a boundary condition for the sources, wherein the parameter is from the following group: costs, efficiency, exhaust gas production, outside temperature, time of day, season, outside temperature. An operating point of the source, in particular the heating or cooling operating mode, can be specified. With the help of at least one of these parameters, it is possible to optimally design the utilization of the performance of the sources. The predetermined strategy consists of providing the heating and/or cooling output cost-effectively and/or efficiently and/or with low exhaust gas values and/or with high comfort and/or as quickly as possible. In one embodiment, a cooling output or a heating output, in particular a desired room temperature, is taken into account as a request from the heat sink when controlling the heat sources.

In one embodiment, a desired humidity, in particular a range or a lower limit or an upper limit for a desired humidity, is taken into account as a request of the heat sink when controlling the heat sources.

In a further embodiment, the heat sink is designed, for example, in the form of a room in a building and the boundary conditions taken into account are an outside temperature of the building and/or the weather, in particular sunshine, i.e. direct solar radiation on a building wall or a window and/or a time of day and/or a season and/or an outside temperature averaged over a specified period of time and/or a current inside temperature and/or a humidity in the room. At least one of these boundary conditions, in particular at least two of these boundary conditions and advantageously more than two of these boundary conditions can be taken into account in order to carry out an optimal selection or control of the two sources for supplying the room with the required heating and/or cooling output.

Characteristic curves, diagrams or formulas are stored for the boundary conditions mentioned, with which the parameters, in particular the boundary conditions of the sources, can be determined depending on the boundary conditions of the heat sinks. This enables optimal adaptation of the utilization of the existing sources for the provision of cooling and/or heating output.

Depending on the chosen embodiment, the boundary condition taken into account is whether a source can provide cooling capacity and/or heating capacity.

In a further embodiment, requests and/or boundary conditions of the heat sink are taken into account in order to decide whether a request for heat output or cooling output is sent to the heating/cooling system. In a further embodiment, boundary conditions of the sources are taken into account in order to determine an operating point, in particular an operating mode of at least one of the sources, depending on the request and to supply a cooling output and/or a heat output to the heat sink. In this way, a two-stage method is provided with which an optimized provision of heat and/or cooling output is possible.

In a further embodiment, the boundary conditions and/or requests of the heat sink and/or the source are taken into account with a factor. In this way, it is possible to take into account the various requests and boundary conditions of the heat sinks and/or the sources in such a way that optimal utilization of the sources is possible according to the desired strategy and, in addition, optimal provision of the cooling and/or heating output desired by the heat sinks is achieved.

In one embodiment, the sources are connected to the heat sink via a hydraulic piping system, whereby boundary conditions of the piping system, in particular the presence of valves, mixers, the usability of piping in one or two directions, are taken into account in order to achieve a To determine the operating mode of at least one of the sources and an operating mode of the piping system for supplying the heat sink with heating or cooling power.

Depending on the design chosen, two types of sources can be used. The first type of source is designed to operate in either a heating mode or a cooling mode. The second type of source is designed to operate in a heating mode and a cooling mode.

The invention is explained in more detail below with reference to the figures.

• Fig. 1 eine schematische Darstellung eines Gebäudes mit mehreren Räumen, und
• Fig. 2 eine schematische Darstellung eines Systems zur Bereitstellung von Wärme- und/oder Kälteleistung.

It shows

• Fig. 1 a schematic representation of a building with several rooms, and
• Fig. 2 a schematic representation of a system for providing heating and/or cooling capacity.

Fig. 1 shows a schematic representation of a building 1 in which several rooms 2, 3, 4, 5, 6, 7 are provided. Each room represents a heat sink, i.e. for each room, heat output or cooling output is provided by a heating/cooling system, i.e. by a thermal system 8, depending on the request of the heat sink. The thermal system 8 is arranged, for example, in a basement of the building 1 and has a first, a second and a third source 9, 10, 11. The three sources 9, 10, 11 represent thermal systems with which heat and/or cooling output can be generated. For example, the first source 9 can be a thermal solar system, the second source 10 a heat pump and the third source 11 a gas boiler. Each of the sources 9, 10, 11 has a further control unit 14, 15, 16, with which the operating point, in particular the operating mode, e.g. cooling or heating, of the sources 9, 10, 11 is controlled. In addition, a control unit 12 is provided, which is connected to the other control units 14, 15, 16 of the sources 9, 10, 11. The control unit 12 is also connected to a memory 13. Programs, data, characteristic curves, diagrams and calculation methods are stored in the memory 13.

Depending on the embodiment chosen, the control device 12 can be part of the thermal system 8, in particular one of the sources 9, 10, 11, or it can be installed in one of the rooms 2, 3, 4, for example in the form of a central controller located in a unit. The control device 12 can also be part of an external device, such as a mobile phone or computer.

In each room 2 to 7, a sensor 18 and an input device 17 can be provided. The sensor 18 is provided to measure, for example, the temperature and/or the humidity in the room. The input device 17 is provided so that a user of the room can enter, for example, a desired room temperature and/or a desired humidity. The input device 17 is also designed to forward the entered data to the control device 12.

Furthermore, each room can have a calculation unit 19 that is connected to the sensor 18 and the input device 17. The calculation unit 19 is designed to determine a specific heat and/or cooling output or a temperature profile, for example depending on the actual temperature of the room and/or the air humidity of the room and/or the temperature and/or air humidity desired by a user via the input device 17, and to forward it to the control device 12. When determining the desired temperature, air humidity or the desired heat or cooling output, the calculation unit 19 can take into account other parameters as boundary conditions of the room, such as an outside temperature outside the room or outside the building, weather, i.e. direct sunlight, rain, snow, cloud cover, a time of day, a season and/or an average outside temperature when determining the desired temperature, air humidity or the desired cooling and heat output.

Thus, the calculation unit 19 can calculate an optimal control of the temperature of the room or the heat output or cooling output supplied to the heat sink for the corresponding heat sink, ie the corresponding room, and transmit it to the control unit 12. the calculation unit 19 has a second memory 20 in which characteristic curves, characteristic fields, calculation methods are stored in order to determine a desired target temperature or a course of the target temperature or a desired cooling capacity or heating capacity depending on at least the current room temperature, the desired room temperature and at least one boundary condition such as the humidity in the room, the outside temperature, the weather, the time of day, the season, the average outside temperature.

Depending on the embodiment selected, each input device 17 of each room can transmit corresponding information and/or each calculation unit 19 of each room can transmit a corresponding desired cooling capacity or heating capacity to the control device 12. Depending on the embodiment selected, the calculation units 19 can also be dispensed with.

Fig. 2 shows a schematic representation of a control system with a thermal system 8, which has three sources 9, 10, 11, and which are controlled by the control device 12. Depending on the selected design, more or fewer sources can also be provided. As an example, three heat sinks 2, 3, 4 are shown schematically, which represent, for example, rooms in a building. Depending on the selected design, more or fewer heat sinks can also be provided. The functionality is explained using the first heat sink 2, whereby the heat sinks 2, 3, 4 have the same devices. As already explained, the calculation unit 19 of the first heat sink 2 records inputs from a user via the input device 17, which can include, for example, a desired temperature, a desired temperature profile, a desired air humidity or other specifications. In addition, the calculation unit 19 records, via the sensor 18, as boundary conditions for the first heat sink 2, for example the current room temperature, the current air humidity, an outside temperature and other boundary conditions. Based on the available data, the calculation unit 19 determines a request for a specific heating and/or cooling output for the first heat sink 2. The request is transmitted to the control unit 12. For this purpose, the calculation unit 19 is available via a control line 26 with the control unit 12. The control unit 12 is in turn connected to the sources 9, 10, 11 via a second control line 28. Depending on the selected embodiment, the connection can also be wireless.

In an analogous manner, the calculation units 19 of the second and third heat sinks 3, 4 also transmit a request for a specific heating and/or cooling output to the control unit 12.

In a further embodiment, the input device 17 can be dispensed with, wherein the desired temperature and/or humidity is preset, for example.

In a further embodiment, the calculation unit 19 can be dispensed with and the user's inputs into the input device 17 are transmitted from the input device 17 as a request to the control unit 12. In addition, individual or all known boundary conditions of the heat sink 2 can be transmitted to the control unit 12.

At least one strategy for operating the sources 9, 10, 11 is stored in the memory 13 of the control unit 12. The strategy can, for example, consist of providing the request of the heat sinks quickly, efficiently, inexpensively, with the greatest comfort, with the lowest costs, with the lowest pollutant emissions, with the highest efficiency of the source.

In addition, the control unit 12 is supplied via an input 27 with further data or boundary conditions such as the outside temperature, an average outside temperature, a time of year, an operating state of the first, the second and/or the third source 9, 10, 11, a boundary condition for operating the source 9, 10, 11.

For example, input 27 can be a sensor input. In addition, input 27 can receive data externally, e.g. via an Internet service.

The operating state of the source 9,10,11 can be, for example, a specific operating point or an operating mode such as a cooling mode or a heating mode. Depending on the selected design, the source can be designed to be operated only in a cooling mode or only in a heating mode. Furthermore, the source can be designed to be operated in a cooling mode or in a heating mode.

Parameters that influence or limit the functioning of sources 9, 10, 11 can be taken into account as boundary conditions for sources 9, 10, 11. For example, the weather, i.e. the presence of sunshine or clouds or an outside temperature, can be taken into account as a parameter for a thermal solar system. In addition, the efficiency can be taken into account as the operating state for a heat pump. Furthermore, for example, for a source in the form of a gas boiler, the gas price can be taken into account. In addition, when using an oil heating system, the storage tank or the oil price can be taken into account. In addition, when designing a source as a thermal power system, for example, it can be taken into account whether electrical output is required instead of heating or cooling output.

Each of the sources 9, 10, 11 can be connected to a heat exchanger 29 of the heat sinks 2 to 7 directly or via switching valves, mixers, pumps with hydraulic lines. In addition, the type of heat exchanger 29 can be taken into account as a parameter for the heat sink. For example, the heat exchanger can be designed in the form of underfloor heating, wall heating, a radiator or a heat exchanger with a fan. Furthermore, the source 9, 10, 11 can also be designed as just an electric heating device or cooling device that is arranged in the heat sink 2, 3, 4.

Alternatively, each of the existing sources can be connected to each of the existing heat sinks or to all heat sinks at the same time. Likewise, the existing sources can only be connected to some of the existing heat sinks. The existing hydraulics are taken into account by the strategy.

Each calculation unit 19 can have its own control method with which a request for the delivery of heating or cooling power by the thermal system 8 can be made depending on an input from a user or a predetermined target temperature, independently of boundary conditions, according to predetermined procedures, characteristics and/or diagrams.

In addition, the calculation unit 19 can have limit values for the boundary conditions, in particular working conditions. The limit values are used to prevent too frequent switching between different requests or switching between requests for heating output or requests for cooling output. In addition, a time factor can be taken into account as a damping factor, which specifies that a new request may only be transmitted to the control unit 12 after certain periods of time, such as 15 minutes.

A boundary condition for a heat sink is, for example, the type of heat exchanger 29 of the heat sink 2, 3, 4. The heat exchanger 29 can, as stated above, be designed as a radiator, as underfloor heating, as air heating, as electric heating or as electric cooling or as electric air conditioning. Depending on the existing conditions, the calculation unit 19 determines as a request, for example, a specific water temperature that is to be supplied by the heating/cooling system 8 to operate the underfloor heating or the radiator. The calculation unit 19 thus carries out a local determination of an optimal request.

The control unit 12, on the other hand, carries out a global control of the heat output or cooling output provided by the thermal system 8. The requests of at least one, preferably all heat sinks and the operating states of the sources 9, 10, 11 are taken into account in order to determine, for example, an operating state of at least one source, in particular all sources, or to carry out a change in the operating state of the sources or at least one source. A change in the operating state For example, this can involve switching a source from a heating mode to a cooling mode.

The sources are used according to the boundary conditions and depending on the specified or selectable strategy in such a way that the heat sink is supplied with a desired heat output and/or cooling output. A request from the heat sink is recorded. In addition, boundary conditions of the two sources are recorded and, depending on the strategy, an operating state of at least one source is determined in order to supply the heat sink with a cooling or heat output. For this purpose, corresponding characteristic curves, diagrams and/or calculation methods are stored in the memory 13, which determine the operating state of the source depending on the boundary conditions of the source and the request from the heat sink.

For example, at least one source detects whether the source is in heating mode or cooling mode as an operating state. Then, depending on the boundary conditions of the sources and the operating state of the source, a decision is made as to whether the operating state of the source is changed or not. In this way, all sources can be checked and optimally controlled by the control unit 12. This allows an optimal adjustment of the operating state of the source or sources to be achieved in order to supply the heat sink with the desired heating or cooling output.

The boundary conditions of the sources can be, for example, limit values for switching between the provision of a heat output or the provision of a cooling output, switching frequencies, a maximum or a minimum operating temperature during the cooling mode or the heating mode of the source, etc. In addition, the control unit 12 can have limit values for boundary conditions of the sources 9,10,11, in particular working conditions of the sources. The limit values are used to avoid too frequent switching between different operating states, in particular switching between a heat output or a cooling output. In addition, for example, a time factor can be taken into account as a damping factor, which specifies that only after certain periods of time such as e.g. the source can be switched back and forth between a cooling mode and a heating mode for an hour or a day.

Furthermore, the control unit 12 can use a time-averaged outside temperature as a boundary condition, which determines whether a source is operated in heating mode or cooling mode. For example, if the outside temperature averaged over a day is above a specified comparison value, at least one source can be switched from heating mode to cooling mode.

The control unit 12 can pursue various strategies to provide a desired heating or cooling output for at least one heat sink. The strategy can be predetermined or selected or set by a user using an input device. The strategy can take into account the type of source, boundary conditions of the sources and/or boundary conditions of the thermal system such as the structure of the hydraulic piping system in order to control the operating state of at least one source.

For example, a majority decision can be used as a strategy. Depending on whether more sinks require cooling or heating, at least one source or all sources are switched to heating mode or cooling mode. Another strategy can be the strategy of mutual agreement. In this case, an operating state of the source, i.e. switching from cooling mode to heating mode or vice versa, is only carried out if all sinks request a changed mode, i.e. cooling instead of heating.

Another strategy is to prioritize a selected operating mode. For example, if the heat mode is prioritized, all sources are in a cooling mode and a temperature of 5°C is reached during the night, for example, the system automatically switches to a heat mode to protect the Thermosystem 8 against frost.

In a further embodiment, a strategy is selected that is determined by the outside temperature. Depending on the outside temperature, it is determined whether the at least one source is operated in a heating mode or in a cooling mode. To avoid too frequent fluctuations, for example, time-averaged outside temperatures or different switching points with a distance of a few degrees Celsius are used to switch from cooling mode to heating mode and from heating mode back to cooling mode. For example, if an outside temperature exceeds 23°C, the system can switch to cooling mode and if it falls below 17°C, the system can switch to heating mode. The outside temperature can, for example, be averaged over an hour. In addition, the distance between two switching points can also have a different value, for example 3°C. In addition, a strategy can also be used that consists of a combination of the strategies described.

Furthermore, a strategy can be set up in such a way that one source is provided for a basic supply, such as a heat pump, that another source is used preferentially, e.g. a solar thermal system, and that a third source is used for a rapid temperature change or a peak load, e.g. a gas boiler. It can also be provided that sources that are not required are used to generate electricity.

The method described has the advantage that the calculation unit 19 transmits an optimal request to the control unit 12 for each sink. The control unit 12 knows the conditions of the available sources and their operating state. In addition, a strategy for operating the sources is specified for the control unit 12. The control unit 12 can thus provide an optimal provision of the heat or cooling output depending on the requested heat or cooling output, depending on the specified strategy and the available sources. This method enables optimization when operating the sources.

Claims (13)

1. Method for controlling a heating/refrigerating system (8) comprising at least one source (9, 10, 11) for providing a cooling and/or heating output for at least one heat sink (2, 3, 4, 5, 6, 7), in particular a room of a building (1),

   wherein, in a first step, a request of the at least one heat sink (2, 3, 4, 5, 6, 7) for a heating output or refrigerating output is detected,

   wherein, in a second step, at least one boundary condition of the at least one source (9, 10, 11) is detected, wherein the boundary condition for the sources (9, 10, 11) that is used is a characteristic curve, a characteristic diagram or a formula for providing the refrigerating and/or heating output on the basis of at least one parameter, the parameter being from the following group: cost, efficiency, exhaust gas generation, outside temperature, time of day, time of year, an average outside temperature, promptness of the provision, comfort, wherein, during the second step, at least for one source (9, 10, 11) as operating state it is detected whether the source is in heating mode or in cooling mode, and

   wherein, in a third step, a strategy is taken as a basis to define an operating state of at least one source (9, 10, 11), wherein, during the third step, the at least one boundary condition of the at least one source (9, 10, 11), the operating state of the at least one source (9, 10, 11) and the strategy are taken as a basis to make a decision as to whether the operating state of the source (9, 10, 11) is changed,

   wherein the specified strategy consists in providing the heating and/or refrigerating output inexpensively and/or efficiently and/or with low exhaust gas values and/or with high comfort and/or as quickly as possible.
2. Method according to Claim 1, wherein the boundary condition of the heat sinks (2, 3, 4, 5, 6, 7) that is taken into account is an outside temperature and/or the weather and/or a time of day and/or a time of year and/or an outside temperature averaged over time and/or a temperature inside the heat sink (2, 3, 4, 5, 6, 7) and/or a humidity in the heat sink (2, 3, 4, 5, 6, 7).
3. Method according to either of the preceding claims, wherein requests made by and/or boundary conditions of the heat sink (2, 3, 4, 5, 6, 7) are taken into account in order to make a decision as to whether a request for heating output or cooling output is sent to the heating/refrigerating system (8).
4. Method according to Claim 3, wherein the boundary conditions of the sources (9, 10, 11) are taken into account in order, on the basis of the request, to define an operating point, in particular an operating mode, of at least one of the sources (9, 10, 11) and to supply a refrigerating output and/or a heating output to the heat sink (2, 3, 4, 5, 6, 7).
5. Method according to one of the preceding claims, wherein requests made by and/or boundary conditions of the heat sink (2, 3, 4, 5, 6, 7) and/or the boundary conditions of the sources (9, 10, 11) are taken into account with a factor, and wherein at least two requests made by and/or two boundary conditions of the heat sinks (2, 3, 4, 5, 6, 7) are taken into account in order to define an operating mode of the sources (9, 10, 11).
6. Method according to one of the preceding claims, wherein the at least one source (9, 10, 11) is connected to one or more heat sinks via a hydraulic line system, wherein boundary conditions of the line system, in particular the presence of valves, of mixers or the usability of lines in two directions are taken into account in order to define an operating mode of the sources (9, 10, 11) and an operating mode for the use of the line system of the heat sink (2, 3, 4, 5, 6, 7) with heating or refrigerating output.
7. Method according to one of the preceding claims, wherein at least a second heat sink (2, 3, 4, 5, 6, 7) is provided, wherein requests made by and/or boundary conditions of the second heat sink (2, 3, 4, 5, 6, 7) are taken into account in order to make a decision as to whether a request for heating output or cooling output is sent to the heating/refrigerating system (8) by the second heat sink (2, 3, 4, 5, 6, 7), and wherein boundary conditions of the sources (9, 10, 11) are taken into account in order, on the basis of the requests made by the two heat sinks (2, 3, 4, 5, 6, 7), to define an operating point, in particular an operating mode of the two sources (9, 10, 11) and supply a refrigerating output and/or a heating output to the heat sinks (2, 3, 4, 5, 6, 7).
8. Method according to one of Claims 3 to 7, wherein boundary conditions averaged over time of the at least one source (9, 10, 11) are taken into account in order, on the basis of the request made by at least one heat sink (2, 3, 4, 5, 6, 7), to define operating modes of the sources (9, 10, 11) and to supply a refrigerating output and/or a heating output to the heat sinks (2, 3, 4, 5, 6, 7).
9. Method according to one of the preceding claims, wherein the at least one source (9, 10, 11) is designed to be operated either in a heating mode or in a cooling mode or in a heating mode and in a cooling mode.
10. Method according to one of the preceding claims, wherein a time factor is taken into account as damping factor, wherein the time factor defines that a switch back and forth between a cooling mode and a heating mode of the source (9, 10, 11) is only made after certain periods of time.
11. Method according to one of the preceding claims, wherein the boundary condition taken into account of the heat sink (2, 3, 4, 5, 6, 7) is an outside temperature averaged over time.
12. Method according to one of the preceding claims, wherein use is made of different switchover points for the outside temperature of a few degrees Celsius, in order to switch a source (9, 10, 11) from a cooling mode back to the heating mode and from the heating mode back to the cooling mode.
13. Control unit (12) designed to carry out a method according to one of the preceding claims.

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