Method, system and apparatus for controlling heating and cooling system for commercial or industrial entities

Abstract

A method for controlling thermal energy distribution in a commercial or industrial entity having a waste heat generation loop connected to a primary side of a heat exchanger, a secondary side of which is connected to a heat recovery unit (HRU). The heat consuming loop is connected to the heat sink side of the HRU. The method determines a first temperature range in which the waste heat generation circuit can operate at its optimal energy efficiency ratio. A second temperature range between a predetermined upper limit temperature and a predetermined lower limit temperature is determined using the first temperature range and a heat exchange capability of the heat exchanger such that the waste heat generation loop can stably operate at its optimal energy efficiency ratio (EER). And controlling the temperature of the fluid in the return line by controlling one or more flow valves mounted at the at least one or more thermal energy consumers such that the temperature in the return line does not exceed a predetermined upper limit temperature and does not drop below a predetermined lower limit temperature.

Description

Technical Field

[0001] The present invention relates to a method, system and apparatus for controlling a thermal energy distribution system for a commercial or industrial entity. The present invention particularly relates to a method for optimizing energy distribution, especially thermal energy distribution during service and non-service times of a commercial or industrial entity (e.g., a supermarket, a large warehouse for refrigerated or frozen storage of food, or any other building that generates waste heat through a thermodynamic cycle process). The present invention preferably uses a heat recovery unit (HRU) to collect, forward and / or transmit the waste heat that occurs / generates for use in a heat consumption circuit (e.g., a heating, ventilation and air conditioning (HVAC) system) and / or a water heating system that uses water as an energy transmission medium. However, the present invention also covers heating systems that use other types of heat transmission media (e.g., gas or air, etc.). In addition, the present invention is not limited to one waste heat generation circuit in a commercial or industrial entity. It is known and obvious to a person skilled in the relevant art that multiple such heat generation circuits can be connected to one HRU. It is preferred, but not limited to, to use a waste heat generation circuit of the vapor compression refrigeration type. However, other types of cycle processes can also be connected to the heat source side of the HRU, such as distillation processes, etc. Background Art

[0002] It is known in the art to transfer waste energy (e.g. from cooling or refrigeration systems such as refrigerated counters or frozen food compartments in supermarkets or the like) to an HRU and to further transfer the waste heat to a heat consuming system for building climate control and / or heating, for example, to an HVAC system of a supermarket in which a refrigerated counter or frozen food compartment is installed. The waste heat from the waste heat generating system / loop is usually taken from the hot gas / steam after the refrigerant compression step of the cycle process and before the compressed gas / steam enters a cooler or condenser. A gas-liquid heat exchanger is used to transfer the thermal energy of the hot gas / steam from the cycle process as waste heat to a liquid energy transfer medium (usually water) used in the HRU. The heat is usually forwarded from the HRU to a heat consuming loop (e.g., an HVAC system for interior heating) via a liquid-liquid heat exchanger for domestic hot water preparation, for filling a thermal storage tank, and / or for providing thermal energy to surrounding buildings or a district heating network.

[0003] The supermarket mentioned above is only one example of many commercial places or entities to which the present invention can be applied. The present invention also includes other locations such as fabrics, office buildings, sports facilities, event facilities, etc., because in all these entities there are waste heat producers installed for many conceivable functions, such as air conditioning, machinery, any kind of cooling or refrigeration system, etc. For the purpose of illustration only, the present invention is described below mainly with the help of a supermarket as a representative example of an entity to which the present invention can be applied.

[0004] In the further course of the description, when a vapor compression refrigeration system is mentioned, the system is used only as an example to simplify and illustrate the disclosure of the basic concept of the present invention. The same applies to the example of an HVAC system which is preferably used as a representative and illustrative example of a heat consumption loop at the heat sink side of the HRU. All of these examples are not intended to limit the scope of the present invention's concept, as the description of the present invention's concept is intended to be as simple as possible. A person skilled in the relevant art will find numerous other examples of waste heat generation loops and waste heat consumption loops that can be connected together through a heat recovery unit (HRU). Therefore, it is preferred to use a gas-liquid heat exchanger to connect the vapor compression cycle process to the heat source side of the HRU.

[0005] As is known in the art, waste heat is usually accumulated or stored in the HRU for further use elsewhere, such as in an HVAC system or loop. The HVAC system and the waste heat generating loop are often driven and controlled independently and separately according to their respective needs. Therefore, the waste heat energy generated is not effectively utilized because the waste heat generating loop, especially the cooling or refrigeration system, should be operated at its best energy efficiency ratio (EER). Since these waste heat generating loops are used in refrigerated counters or frozen food compartments in supermarkets, it is crucial to maintain the temperature in these compartments at a specified temperature so as not to endanger the quality of the food. On the other hand, heat consumption loops (such as HVAC systems) usually use heating systems, which should also be operated in an efficient manner, preferably at their best performance coefficient (COP) to maintain the ambient temperature / room temperature in the entity (such as a supermarket) so that customers and employees feel comfortable. In this context, the term "energy efficiency ratio" (EER) is usually used in the art for cooling or refrigeration systems, and the term "coefficient of performance" (COP) is used for heating systems, but sometimes these terms are used in reverse.

[0006] CA 2551268 A1 describes a thermal energy distribution system for a restaurant kitchen, which has a heat recovery unit, a waste heat generation loop is connected to the heat recovery unit through a heat exchanger at the heat source side, and a heat consumption loop is connected to the heat sink side of the heat recovery unit, the heat consumption loop has at least one or more thermal energy consumers, and is used to provide thermal energy to the restaurant kitchen, wherein one or more temperature-controlled flow valves are installed and controlled by a control unit. Summary of the invention

[0007] Therefore, the object of the present invention is to provide an improved heat distribution method and a thermal energy distribution system for a commercial or industrial entity, which overcomes the disadvantages of the prior art and provides a more efficient use of the thermal energy generated in the entity. The present invention should reduce the overall energy consumption of an entity having an HRU, both sides of which (the waste heat generating side and the heat demanding side) are controllable and can be operated in a coordinated manner, so that the electrical energy, thermal energy and / or mechanical energy supplied from the outside to the thermal distribution system of the entity is optimally utilized and so that at least the waste heat generating circuit within the thermal energy system, in particular the food refrigeration or cooling system, can be operated at its optimal energy efficiency ratio (EER). At the same time, the method should be simple in terms of application and implementation, as well as monitoring of the thermal energy distribution system during operation. Preferably, the method of the present invention can be installed in a cost-effective manner to an already existing thermal energy distribution system. At the same time, the method according to the present invention should be able to maximize and cost-effectively utilize the waste heat energy that occurs for the overall energy consumption of a commercial or industrial entity, wherein the arrangement / installation of the equipment and devices implementing the method of the present invention should be simple and at the same time cost-effective.

[0008] The object of the invention is solved by a method as claimed in the independent claim 1. Preferred embodiments are given by the dependent claims that are dependent on claim 1. The object is also solved by a thermal energy distribution system as claimed in the independent system claim, preferred embodiments of which are described in the dependent claims that are directly or indirectly dependent on the independent system claim. The problem of the invention is further solved by a flow valve as claimed in a further independent device claim. Preferred embodiments of the flow valve are provided in the dependent claims that are directly or indirectly dependent on the independent device claim.

[0009] The method according to the invention controls the distribution of thermal energy in a commercial or industrial entity having a waste heat generating circuit connected to the primary side of a heat exchanger. Connected to the secondary side of the heat exchanger is the heat source side of a heat recovery unit (hereinafter also referred to as: HRU). Connected to the heat sink side of the HRU is a heat consumption circuit comprising at least one thermal energy consumer, such as a heating, ventilation and air conditioning (HVAC) circuit.

[0010] The method of the invention determines in a first step a first temperature range of the medium / fluid of the waste heat generation circuit at the outlet of the primary side of the heat exchanger, within which the waste heat generation circuit can operate at its optimal energy efficiency ratio (EER). Generally speaking, in thermodynamic processes, waste heat is dissipated after the compression step of the cyclic process using a gaseous fluid / refrigerant. Therefore, the optimal fluid temperature at the output of the heat exchanger is reached when, after the fluid has passed through the heat exchanger, no further cooling step is required for the fluid of the waste heat generation circuit (because the temperature of the fluid leaving the heat exchanger is at a temperature that is optimal for the expansion step of the cyclic process). When the heat exchanger is not used, a cooler or condenser will reduce the fluid temperature to this temperature in order to operate the waste heat generation circuit at its optimal energy efficiency ratio (EER). Therefore, this temperature forms the lower limit of the first temperature range and is usually defined in the design phase of the waste heat generation circuit or, in the case of a purchasable unit or installation, is provided in the technical data sheet.

[0011] The upper temperature limit of the first temperature range is given by the cooling capacity of the condensation step, i.e. by the capacity of the cooler or condenser, to provide an optimum fluid temperature for the expansion step. Adding the temperature difference achievable by the compression step to the temperature optimum for entering the expansion step provides the upper limit of the first temperature range.

[0012] As previously mentioned, the optimum temperature for entering the expansion step is provided by the cyclic process used as the waste heat generation loop. It will be apparent to those skilled in the relevant art that the most efficient use of waste heat is given when no cooling or condensing step is used (i.e., no additional energy has to be supplied to cool the fluid of the waste heat generation loop after leaving the outlet at the primary side of the heat exchanger). Since the heat demand or thermal energy consumption on the heat sink side of the HRU is unstable, the fluid temperature at the second side of the heat exchanger connected to the HRU will also be unstable, and therefore a cooler or condenser in the waste heat generation loop will still be needed to adjust the fluid temperature of the waste heat generation loop fluid to the optimum expansion temperature.

[0013] Since the cooling capacity of a cooler or condenser is usually defined during the design phase of the equipment used in a commercial or industrial entity, a person skilled in the relevant art can determine the first temperature range of the waste heat generation loop fluid without any problems. The equipment often used is a standard equipment, the cooling capacity of which is provided in the technical data sheet. Therefore, in order to determine the first temperature range at the outlet of the heat exchanger that is optimal for the waste heat generation loop, a person skilled in the relevant art only needs to consult the technical specifications of the waste heat generation equipment, where the input temperature of the expansion step provides it with the lower limit of the first temperature range. This temperature is added to the temperature difference that can be achieved by the cooling / condensing step, providing it with the upper limit of the first temperature range.

[0014] The next step of the method according to the invention uses the specifications and technical data of the selected heat exchanger and the selected HRU to determine a second temperature range for the fluid in the return line of the heat consumption circuit by calculation based on the first temperature range. Here, basically, the first temperature range and the heat transfer capabilities of the two units (heat exchanger and HRU) enable a person skilled in the relevant art to determine this second temperature range for the return temperature of the fluid of the heat consumption circuit. Therefore, when the technical specifications of the heat exchanger at the heat sink side of the heat recovery unit (HRU) used and the technical specifications of the HRU itself are known, a person skilled in the relevant art can derive the second temperature range at the inlet of the heat sink side of the HRU based on the first temperature range. This second temperature range provides it with a predetermined upper limit temperature (T max ) and the predetermined lower limit temperature (T min ), within the predetermined upper limit temperature and the predetermined lower limit temperature, the waste heat generating circuit (10) on the other side of the HRU can stably operate at its optimal energy efficiency ratio (EER);

[0015] Thus, when the temperature of the fluid in the return flow of the heat consumption loop is maintained within the second temperature range, the temperature of the fluid at the outlet of the heat exchanger at the heat source side of the HRU is within the first temperature range, within which the waste heat generation loop can operate at an optimal energy efficiency ratio (EER). In the most preferred case, the temperature reached at the outlet of the heat exchanger is the inlet temperature of the expansion step of the waste heat generation loop. In this case, no external energy is required to operate the condenser or chiller, and the overall energy balance of the commercial or industrial entity can be reduced.

[0016] In the final step, the method of the present invention controls the fluid temperature and / or return flow rate in the return line of the heat consumption circuit by controlling one or more flow valves installed at at least one heat energy consumer, so that the temperature in the return line of the heat consumption circuit to the HRU does not exceed a predetermined upper limit temperature (T max ), nor does it drop below the predetermined lower temperature limit (T min ), the predetermined upper limit temperature and the predetermined lower limit temperature together define a second temperature range. Therefore, as long as the temperature in the return line of the heat consumption loop is maintained within the second temperature range, in the case where a heating system is adopted at the heat source side of the heat recovery unit HRU, the waste heat generation loop can be stably operated near its optimal energy efficiency ratio (EER) or coefficient of performance (COP).

[0017] In addition, in order to control the temperature to a predetermined upper limit temperature (T max ) and the predetermined lower limit temperature (T min), the flow through the return line can be monitored and controlled. Since a variety of different types of consumers can and will be installed in the thermal energy consumption loop, the fluid temperature at the inlet of the HRU at the heat sink side will be a mixed temperature of the different return lines of the various consumers. Therefore, by monitoring and controlling the flow in the return line of the consumer, the temperature of the fluid entering the HRU at the heat sink side can be affected. The temperature of the fluid entering the HRU at the heat sink side can be monitored, for example, by an additional temperature sensor, which provides the temperature signal to one or more consumers or to an upper or supervisory unit, which is able to send a corresponding signal / command to one or more flow valves. Therefore, changing the flow can be used as an additional optimization to achieve an optimal temperature at the primary outlet of the heat exchanger in the thermal energy distribution equipment of a commercial or industrial entity, so as to always operate the waste heat generation loop at the best energy efficiency ratio (EER).

[0018] In other embodiments, the control of the temperature in the return line and / or the control of the flow in the return line can be used to allow the heat demand in the heat consumer circuit to be changed, wherein the temperature in the return line towards the HRU can be kept within a predetermined temperature range. Therefore, the method according to the invention preferably controls whether the temperature in the return line exceeds a predetermined upper temperature limit (T max ) or drops below a predetermined lower temperature limit (T min ), and only when the fluid temperature leaves the second temperature range, commands the opening or closing of the flow valve at the consumer in the heat consumption circuit, and the corresponding flow channel, to keep the temperature within the second temperature range. For example, if the temperature in the return line of the heat consumption circuit reaches T max (upper limit temperature), the method commands a flow valve at the return line of at least one heat consumer to close the return line and reduce the consumer return flow - provided that the fluid temperature in the return line of the heat consumer is higher than T max Therefore, when the temperature of the fluid at the return from the consumer is lower than T max , the flow valve can be commanded to open and increase the flow through the consumer return line.

[0019] In another case, when the temperature in the return line of the heat consumption circuit reaches T min (lower limit temperature), the method commands a flow valve in the return line of at least one heat consumer to open the return line and increase the consumer return flow - provided that the fluid temperature in the return line of the heat consumer is higher than T min Therefore, when the temperature of the fluid at the return from the consumer is lower than T min When the flow valve is commanded to close the flow channel, the flow through the consumer return line is reduced.

[0020] As already indicated above, a priority of the method according to the invention is to provide the waste heat generation circuit with optimal fluid temperature conditions at the primary outlet of the heat exchanger connected to the heat source side of the HRU. This is preferably at a temperature that does not require the use of a cooler or condenser in the waste heat generation circuit, i.e., to provide an optimal refrigerant temperature for expansion at the primary outlet to achieve the best energy efficiency ratio (EER) of the waste heat generation circuit. In other words, since all waste energy is intended to be transferred to the HRU through a heat exchanger (preferably a gas to liquid heat exchanger), the amount of waste heat can be flexibly used within the HRU and in particular in the heat consumption circuit. For example, it can be used to heat the interior of a commercial or industrial entity, or to heat water in a (domestic) tap water storage tank, evaporative air conditioning or refrigerant for a refrigerator. Here, a technician in the relevant field will find many other possibilities for utilizing waste heat, including providing excess energy to an external heating network.

[0021] Preferably, a heating, ventilation and air conditioning (HVAC) system for a commercial or industrial entity to which the method of the present invention can be applied is installed on the heat source side of the HRU, the system comprising a plurality of different heat energy consumers, each of which is equipped with a separate flow valve - which is standard in the relevant art. Therefore, the method according to the present invention can be applied to each flow valve individually or by grouping the flow valves, so as to achieve the desired fluid temperature in the return line of the heat consumption circuit within a predetermined temperature range.

[0022] In other cases, when it is not possible to convey all the waste energy or waste heat to the HRU, the refrigerant of the waste heat generation circuit will comprise a temperature at the outlet of the heat exchanger that is higher than the temperature that is optimal for expansion, so that a cooler or condenser is required to (further) reduce the temperature of the refrigerant. This may happen, for example, on a hot summer day, when one or more vapor compression cycles serving as waste heat generation circuits are installed in a supermarket, all operating at high performance, while on the other side of the HRU (the heat consumption side of the HRU) only a low demand for thermal energy is indicated (e.g. only air conditioning is required, but no ambient heating or hot tap water is required). In this exemplary case, the capacity of the heat consumption circuit to bear all the waste energy is not sufficient to meet the task of the method according to the invention, i.e. to keep the temperature in the return line of the heat consumption circuit within a predetermined temperature range so that the waste heat generation circuit operates at its optimal energy efficiency ratio (EER). However, if this happens, the temperature at the outlet of the heat exchanger will be too high for the expansion step and must be cooled by a cooler or condenser, thereby dissipating the thermal energy into the environment. This not only results in a loss of thermal energy, since it also means that additional (electrical) energy is supplied to the cooler / condenser to reduce the temperature of the fluid before expansion. It may be necessary to consider connecting more consumers or more thermal storage capacity at the heat consumption circuit to avoid energy losses.

[0023] Another situation that may occur is that the energy demand of the heat consumption circuit is too high, so that the temperature in the return line falls below the predetermined lower temperature limit T min , while the energy consumption in the heat consumption circuit cannot be reasonably reduced. Here, the method of the present invention provides a bypass line that allows all or part of the fluid to bypass the heat exchanger and mix it again with the outlet flow from the heat exchanger through a three-way valve before entering the expansion step. Here, a cooling step is often not required because the two flows can be mixed at a temperature that is optimal for the expansion step. This situation is not a preferred operating point for the method of the present invention, because the present invention aims to transfer all waste energy to the heat sink side of the HRU, that is, to the heat consumption circuit. Therefore, the bypass step should be omitted, which means that during normal operation of the heat distribution system according to the present invention, the bypass line to the heat exchanger should remain closed. In this case, measures to reduce energy consumption at the heat consumption circuit can be considered, such as improving isolation or reducing room temperature in commercial or industrial entities or reducing tap water temperature. Alternatively, an external heating device can be installed on the heat consumption circuit so that the temperature in the return line can be increased again to at least T min - a predetermined lower temperature limit. Another measure would be to minimize the waste energy (heat) generated, for example by improving the insulation of food cooling compartments. For food refrigerants or cooling compartments in waste heat generating circuits, increasing the temperature is not a viable option as this would compromise food quality.

[0024] The problem of improving the distribution of thermal energy in a commercial or industrial entity is solved according to the invention by a thermal energy distribution system installed in the commercial or industrial entity, the thermal energy distribution system having a heat recovery unit (HRU), to which a waste heat generating circuit is connected on the heat source side via a heat exchanger. A heat consumption circuit is connected to the heat sink side of the HRU, the heat consumption circuit having at least one or more thermal energy consumers for providing thermal energy to the commercial or industrial entity. A temperature-controlled flow valve is installed in each return line of at least one or more thermal energy consumers. Each flow valve comprises a control unit and a temperature sensor for monitoring the temperature in the return line. Each control unit is capable of commanding an actuator of the flow valve to open or close a corresponding flow valve channel so that the temperature in the return line of the consumer does not exceed a predetermined upper limit temperature (T max ), nor does it drop below the predetermined lower temperature limit (T min ).

[0025] As described above, the thermal energy distribution system configured in this way is able to realize the basic concept of the present invention. In particular, by arranging controllable flow valves in the return lines of the consumers, the thermal energy distribution system of the present invention is able to keep the temperature of the fluid in the joint return line from the heat consumption circuit to the HRU within a temperature range that preferably allows the waste heat generation circuit at the other side of the HRU to operate at the best energy efficiency ratio (EER). For an installed (or still only designed) thermal energy distribution system, the heat transfer capacity of all involved heat exchangers in the HRU and the heat transfer capacity of the heat exchanger between the HRU and the waste heat generation circuit are known, and the fluid temperature range of the waste heat generation circuit entering the cooler or condenser is also known, so it is not necessary to spend too much effort to determine the temperature range in which the fluid of the heat consumption circuit should enter the HRU. This temperature range can be controlled by the control unit at the flow valve of each consumer, and the temperature in the joint return line can finally be maintained within a predetermined temperature range with the (additional) help of a temperature sensor at the heat sink side inlet of the HRU.

[0026] In a preferred embodiment of the present invention, the predetermined upper temperature limit (T max ) and the predetermined lower temperature limit (T min ) can be set at the individual control units in dependence on the waste heat generation circuit being able to operate at its best energy efficiency ratio (EER). Different temperature ranges can be set here at different consumers or consumer groups. Finally, the inlet temperature of the HRU must be kept within the calculated temperature range to ensure that the waste heat generation circuit at the other side of the HRU can operate at the best energy efficiency ratio (EER).

[0027] In another embodiment of the present invention, the flow valve at the return line of the consumer is a pressure-independent or pressure-dependent flow valve controlled, for example, in an on / off or regulating manner. The actuation of the flow valves, respectively, by their actuators can be analog controlled by 0-10V / 0-20mA current, or can be digitally controlled by any communication protocol. This can be achieved by solenoids or other electric drivers known in the art. Preferably, the control unit of the flow valve generates a corresponding command, with which the actuator movement can be performed in an appropriate manner so as to start, disable, limit, open or close the flow valve channel according to the temperature in the return line measured by the temperature sensor of the associated flow valve or the temperature provided by the temperature range setting signal received, for example, from a building management system or another temperature sensor (e.g., from a temperature sensor installed near the inlet in the return line to the HRU).

[0028] In another preferred embodiment of the thermal energy system according to the invention, the waste heat generation circuit is a CO 2or any other gas as a refrigeration circuit for refrigerant. Here, a person skilled in the relevant art can think of a variety of possible cycle processes that can be used to implement the present invention, which are not necessarily vapor compression cycle processes, because the Carnot process can also use steam, and its residual heat after the expansion stage can be used as waste heat according to the present invention, and the Carnot process is optimized by increasing the temperature difference when the Carnot process is running.

[0029] On the other side of the HRU, the heat consumption loop is preferably a heating, ventilation and air conditioning (HVAC) loop with all possible heat consumers known to a person skilled in the relevant art. Here, the individual fluid temperatures in the return lines of different consumers or consumer groups can be different from each other, because they can be mixed in the joint return line of the HVAC loop to meet the criterion that the inlet fluid temperature at the heat sink side of the HRU is within a predetermined required temperature range, so that the cycle process on the heat source of the HRU can be operated with the best energy efficiency ratio (EER) or the best coefficient of performance (COP).

[0030] To this end, according to the present invention, preferably flow valves are used, which include an electromechanically operable actuator configured to open and close a flow channel through the flow valve, and which also include a temperature sensor for monitoring the temperature of the medium in the fluid pipeline. The control unit of the flow valve is configured to set a predetermined upper temperature limit (T max ) and the predetermined lower temperature limit (T min ) and command the actuator of the flow valve to open or close the flow channel. The microcontroller in the control unit is capable of receiving a temperature signal from the temperature sensor and determining whether the temperature signal indicates that the fluid / medium temperature is within a preset temperature range, below a preset temperature range, or above a preset temperature range. The microcontroller in the control unit of the flow valve is configured to generate an open valve command to the actuator of the flow valve when the temperature signal indicates that the fluid / medium temperature is below the temperature range, or to generate a close valve command to the actuator when the temperature signal indicates that the medium temperature is above the temperature range. In the event that the temperature sensor of the flow valve detects that the fluid temperature is within the preset / predetermined temperature range, no command is generated, and the flow through the flow valve is maintained as long as the sensed temperature does not leave the predetermined temperature range.

[0031] As described above, a separate flow valve is provided for each consumer return line in the heat distribution system of the present invention. Preferably, a separate temperature range can be set at each flow valve, wherein the flow valves of a group of consumers can be set to the same predetermined temperature range. To this end, the control unit of the flow valve also includes a digital interface, which is capable of receiving an external temperature range setting command, or a temperature or command signal by wire or wirelessly, so as to be able to monitor and control the fluid temperature in the associated return line. The digital interface of the control unit may also be capable of receiving a predetermined upper temperature limit (T max ) and the predetermined lower limit temperature (T min ), wherein the superior or supervisory control system may be a building management system (BMS). In this embodiment, the flow valve according to the present invention may be part of a building management system, wherein the flow valve includes its own intelligence to decide whether the flow through the flow valve should remain unchanged or should be reduced or increased based on the measured temperature of a temperature sensor belonging to the flow valve.

[0032] Although the present invention is described above with only one waste heat generating loop, a person skilled in the relevant art will readily recognize that multiple waste heat generating loops can be connected to one HRU, which transfers heat to one or more heat consuming loops, which are not necessarily HVAC systems. However, it is preferred that the HVAC system of the commercial or industrial entity is connected to the heat sink side of the HRU. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] With the aid of the accompanying drawings, a preferred embodiment of the heat distribution method according to the present invention is explained in more detail to enhance the understanding of the basic concept of the present invention and to illustrate the embodiments, alternatives, modifications and changes that can be made to the basic concept of the present invention without departing from the scope of the basic concept of the present invention. Therefore, the illustrated embodiments do not limit the scope of the concept of the present invention, but only represent possible design alternatives, which can be modified within the knowledge of technicians in the relevant fields without departing from the scope of the present invention. Therefore, all these embodiments, alternatives, modifications and changes are covered by the claimed invention. In the figure:

[0034] Figure 1 A thermal energy distribution system according to the present invention is schematically shown;

[0035] Figure 2 schematically shows a graph of temperature variation over time according to the present invention;

[0036] Figure 3 A flow valve according to the invention is schematically shown. DETAILED DESCRIPTION

[0037] Figure 1 An embodiment of a thermal energy distribution system according to the present invention is schematically shown. Figure 1 , a waste heat generation loop 10 is depicted and outlined with a dotted line. The cyclic process of the waste heat generation loop 10 runs counterclockwise and is only exemplarily representative of a vapor / gas compression refrigeration system. As known to those skilled in the relevant art, these processes can use different fluids / mediums as refrigerants, which can exist in liquid and / or gaseous form during a cycle. Since the cyclic refrigeration processes are known to those skilled in the relevant art, further detailed description of these processes is omitted at this time.

[0038] As is usually the case in a cyclic waste heat generating loop 10, the compressor 15 pressurizes the refrigerant after the evaporation step (if appropriate), so that the refrigerant is heated and directed towards a cooler or condenser 19. According to the thermal energy distribution system of the invention, the hot refrigerant is first cooled and then enters the cooler or condenser 19 at the primary side 21 of a heat exchanger 20, the secondary side 22 of which is connected to a HRU (heat recovery unit) 30. The hot refrigerant enters the heat exchanger 20 at the primary side 21 at an inlet 25 and leaves the heat exchanger 20 at an outlet 26 on the same primary side of the heat exchanger 20, but at a lower temperature, because the cooler HRU refrigerant flows through the secondary side 22 of the heat exchanger 20. The HRU refrigerant (often a liquid refrigerant, such as water) is able to receive the (waste) heat from the (gaseous) refrigerant of the waste heat generating loop 10 and to transmit / transfer it further to the heat consumption loop 40 via other heat exchangers (usually liquid / liquid heat exchangers).

[0039] In the heat consumption loop 40 connected to the heat sink side of the HRU 30, at least one heat consumer 43 is arranged for dissipating or storing heat. The at least one heat energy consumer can be selected from a plurality of possible heat energy consumers, Figure 1 Three examples are shown: air conditioning or ventilation system 43.1, hydronic heating 43.2, domestic hot water (tank) 43.3. Here, a person skilled in the relevant art will find multiple other consumers 43.n that use thermal energy, such as (floor) heating, de-icing, evaporator solutions, all of which can be classified under the term "heating, ventilation and air conditioning (HVAC) system". Therefore, the concept of the present invention covers all these possibilities. Finally, the waste heat generated in the waste heat generation loop 10 can be used in an environmentally friendly manner on the heat sink side of the HRU by numerous consumers 43.n, where "n" means that a device / element can appear n times, where equal numbers indicate a group of related parts.

[0040] According to the method of the present invention, the temperature T in the return line 42 to the HRU 30 is controlled and maintained within a temperature range so that the waste heat generation circuit 10 on the heat source side of the HRU 30 can operate at its optimal energy efficiency ratio (EER). To this end, the method according to the present invention defines in a first step a first temperature range of the refrigerant of the waste heat generation circuit 10 at the outlet 26 of the heat exchanger 20. This temperature range is derived from the optimal temperature at which the refrigerant should enter the expansion valve 14 in the waste heat generation circuit 10 and which should be constant so that the waste heat generation circuit 10 operates at the optimal energy efficiency ratio (EER) and ensures a constant compartment freezing or cooling temperature, such as in the case of a vapor compression cooling circuit. Figure 1 As shown by way of example. If the refrigerant enters the heat exchanger 20 at the inlet 25 and leaves the heat exchanger 20 at the outlet 26, it can be cooled in the heat exchanger 20 to a temperature that is optimal for the expansion step, without the need for additional cooling by the cooler / condenser 19. Therefore, this temperature that is optimal for the expansion step determines the lower limit of the first temperature range for the refrigerant temperature at the outlet 26. The upper limit of the first temperature range is given by the cooling capacity of the cooler / condenser 19. Therefore, the temperature Δ (delta) / temperature difference that the cooler / condenser can achieve can be added to the optimal expansion temperature and thus provide the upper limit of the first temperature range.

[0041] Since the method according to the invention aims at controlling the temperature T in the return line 42 to the HRU on the heat source side, it is necessary to convert the first temperature range at the outlet 26 of the heat exchanger into a second temperature range of the heat transfer medium (usually also water) in the return line 42 of the heat consumption circuit 40. This conversion can be performed according to the invention, for example, by using the temperature Δ achievable on the secondary side of the heat exchanger 20 and the temperature Δ achievable on the heat source side and the heat sink side of the HRU 30. Thus, for example, by simple arithmetic, the first temperature range can be converted into a second temperature range of the heat transfer medium in the return line 42, respectively in the supply line 36 of the HRU 30 on the heat sink side.

[0042] In the simplified example mentioned above, it is not taken into account that heat can be stored in the HRU itself, which results in a change in the heat transfer rate of the heat exchangers involved in the HRU 30. However, since the HRU is usually monitored according to the storage capacity it occupies, it takes only a small effort for a person skilled in the relevant art to adapt the temperature in the return line 42 to the conditions in the HRU. Therefore, the determination of the second temperature range must not be fixed over time, since it often changes, for example as the level of heat storage in the HRU 30 changes. In any case, the purpose of the method of the invention is to ensure that the refrigerant temperature at the inlet of the expansion step is always at the same temperature, so that the waste heat generation circuit 10 can be operated with an optimal energy efficiency ratio (EER).

[0043] As already explained at the beginning and during the description of the present invention, for the method according to the present invention, it is a priority that the waste heat generation circuit 10 can be operated at its best energy efficiency ratio (EER). In addition, as long as the temperature of the heat transfer medium in the return line 42 is within the predetermined second temperature range, according to the present invention, the refrigerant of the waste heat generation circuit 10 at the outlet 26 is also within the first temperature range. However, if the heat demand at the heat consumption circuit 40 (i.e. at the heat sink side of the HRU 30) is greater than the amount of heat that can be transferred from the waste heat generation circuit 10 to the HRU 30 through the heat exchanger 20, the temperature in the return line 42 may drop below the predetermined lower temperature limit of the second temperature range, making the temperature at the outlet 26 of the heat exchanger 20 too low for optimal operation of the waste heat generation circuit 10.

[0044] In order to prevent the refrigerant temperature at the inlet of the cooler / condenser 19 from being too low, the present invention provides a bypass line 17 which bypasses the inlet 25, the outlet 26 and thus the primary side 21 of the heat exchanger 20. The supply line 12 connects the outlet 26 with the three-way valve 18 and comprises the bypass line 17 as a second inlet. The outlet of the three-way valve 18 is connected to the cooler / condenser 19. According to the present invention, the three-way valve 18 closes the bypass line 17 as long as the temperature in the return line 42 remains within the predetermined upper and lower temperature limits. If the temperature of the heat transfer medium in the return line 42 drops below the predetermined lower temperature limit and the temperature of the refrigerant at the outlet 26 will then also drop below the lower limit of the first temperature range, the three-way valve 18 at least partially opens the bypass line 17 so that the hot refrigerant can mix with the refrigerant which has passed through the primary side 21 of the heat exchanger 20 and is below the predetermined lower temperature limit. Therefore, by the arrangement of the three-way valve 18 and the bypass line 17, the refrigerant temperature can be adjusted to a temperature optimal for the expansion step.

[0045] In another case where the temperature of the heat transfer medium in the return line 42 exceeds a predetermined upper temperature limit (which means that the heat demand in the heat consumption loop is lower than the waste heat provided and transferred through the heat exchanger 20), the storage capacity of the HRU 30 can be used to bear the excess heat energy until the storage device is fully filled. If excess waste heat energy is still generated, the heat must be dissipated to the environment at the heat source side or the heat sink side of the HRU 30. In this case, those skilled in the relevant art may also consider adding a heat distribution system (e.g. Figure 1 The heat distribution system shown) is connected to an external heating grid or to increase the thermal energy consumption at the heat sink side, for example by raising the room temperature in a commercial or industrial entity or by raising the storage temperature for domestic hot water or hydronic heating.

[0046] Figure 2 Two temperature curves are shown, where the continuous curve exemplarily represents a high level of waste heat consumption at the heat consumption circuit 40, and the dashed curve exemplarily represents a low level of heat consumption at the heat consumption circuit 40. It can be concluded from the continuous temperature curve that when the temperature of the heat transfer medium in the return line 42 reaches the predetermined lower limit temperature T min When the temperature is increased according to the method of the invention, the temperature is prevented from falling below the predetermined lower limit temperature T min It can also be concluded from the solid line curve that the method according to the present invention allows the temperature in the return line 42 to be maintained at a predetermined lower limit temperature T min This is because this is a condition for maximally utilizing the waste heat generated by the waste heat generation circuit 10 at an optimum energy efficiency ratio (EER).

[0047] As can be seen from the dashed line, the method according to the invention aims to prevent the temperature of the heat transfer medium in the return line 42 from exceeding a predetermined upper temperature T max At the predetermined upper limit temperature T max At , the waste heat generating circuit 10 operates at its best energy efficiency ratio (EER), however, the cooler / condenser 19 must be driven in order to reduce the temperature of the refrigerant leaving the outlet 26 of the heat exchanger 20. See above for determining the predetermined upper limit temperature T by calculation max and the predetermined lower limit temperature T min Therefore, the method according to the invention preferably aims to reduce the temperature of the heat transfer medium in the return line 42 to a predetermined temperature range T R The closer the temperature of the heat transfer medium in the return line 42 is to the predetermined upper limit temperature T max The more additional (mechanical and / or electrical) energy must be supplied to the cooler / condenser 19 in order to reduce the refrigerant temperature at the outlet 26 to a temperature that is optimal for the expansion step. It can also be seen that it is preferred to follow, for example, a temperature closer to T min (predetermined lower limit temperature) solid line curve. Because at Tmin , the cooler / condenser 19 can be closed or remain closed and no additional work / energy is consumed, which means that the overall energy balance of the thermal energy distribution system according to the present invention is balanced because all waste energy generated is consumed at the heat consumption circuit 40.

[0048] In order to maintain the temperature and / or transport of the heat transfer medium in the return line 42 within the temperature range T R In the method according to the invention, preferably a flow valve 45 is used, which is installed at the return line 42 of each consumer connected in the heat consumption circuit 40. The flow valve 45 according to the invention comprises an electromechanically operable actuator 46, which is configured to open and close the flow through the flow valve 45 and thus through the associated return line 42 (see Figure 1 ) of the flow channel 44. Figure 3 As can be best seen in FIG. 4 , the temperature sensor 47 of the flow valve 45 is used to monitor the temperature of the heat transfer medium in the fluid pipeline 42. The control unit 48 of the flow valve 45 is configured to set a predetermined upper limit temperature T max and the predetermined lower limit temperature T min , and instructs the actuator 46 to open or close the flow passage 44 of the flow valve 45. The microcontroller in the control unit 48 can receive the temperature signal from the temperature sensor 47, and determine whether the temperature signal indicates that the temperature of the heat transfer medium is within the preset temperature range T R Within or below the preset temperature range T R Or higher than the preset temperature range T R The microcontroller will detect when the temperature signal indicates that the temperature of the heat transfer medium is below the temperature range T R In the case of the temperature signal indicating that the temperature of the heat transfer medium is higher than the temperature range T R In this case, a valve closing command is generated for the actuator 46.

[0049] The flow valve 45 according to the present invention is configured to autonomously detect the temperature of the heat transfer medium in the associated return line 42.n of the consumer 43.n. The flow valve 45 is installed in the return line 42.n downstream of the consumer 43.n. Further, the index ".n" is used for the "n"th possible consumer 43, each consumer having a flow valve 45.n installed to the return line 42.n downstream of the consumer 43.n. Wherein "n" is a natural number starting from "1". In Figure 1 In the example of the thermal energy distribution system, “n” equals 3.

[0050] Each control unit 48.n of the flow valve 45.n of the present invention is configured to receive a temperature signal from its own temperature sensor 47.n, for example, periodically, and decide whether the associated actuator 46.n must open or close the flow channel 44.n in order to modify the flow through the flow valve 45.n. As long as the temperature of the heat transfer medium is within the second temperature range T R In this case, the control unit 48.n does not issue any command to the actuator 46.n, and the set flow rate through the flow channel remains constant. R In the case of other than the above, the flow through the flow valve must be adjusted. This is determined by the control unit 48.n, for example, with the aid of a microcontroller arranged in the control unit 48.

[0051] If the temperature of the heat transfer medium in the associated return line 42.n exceeds a predetermined upper temperature limit, the flow through the passage of the flow valve 45.n must be reduced in order to bring the temperature in the associated return line 42.n back to the temperature range T R In this case, the control unit 48.n generates a corresponding command to close the channel 44.n and sends it to the actuator 46.n of the flow valve 45.n in order to reduce the flow channel 44.n or even completely close it. If the temperature of the heat transfer medium in the associated return line 42.n drops below a predetermined lower limit temperature, the flow through the channel 44.n of the flow valve 45.n must be increased in order to bring the temperature in the associated return line 42.n back to the temperature range T R In this case, the control unit 48.n generates a corresponding open channel 44.n command and sends it to the actuator 46.n of the flow valve 45.n in order to increase the flow channel 44.n or even open it completely.

[0052] Thus, for each consumer 43.n, to which a flow valve 45.n is associated, each consumer 43.n can be controlled individually. This enables individual settings to be made for each consumer associated with a flow valve 45.n. For example, a consumer 43.n with a higher temperature but lower flow in the return line 42.n can be set to a temperature T R , which is overall higher than another consumer 43.n+1 with a higher flow rate but lower temperature, for example in the return line 42.n+1. These temperature ranges T RThe temperature range setting may be set manually at each flow valve 45.n individually, or alternatively by a superior or supervisory control system, such as a building management system (BMS). Such a BMS may, for example, monitor the temperature of the combined return line 42 of the heat consumption circuit 40 and send a temperature range modification signal to one or more control units 48.n at the flow valves 45.n so that they may change their temperature range setting in order to meet the second temperature range T required for the temperature of the heat transfer medium at the inlet of the HRU 30. R Therefore, each consumer 43.n does not need to meet the second temperature range T R itself, since only the mixed return flow of the plurality of consumers 43.n must meet this criterion, i.e. be included in the second temperature range T R In order to receive such control or change the setting signal, the flow valve 45 according to the present invention comprises a digital interface 49, by which the flow valves 45.n can be connected to each other via a bus, LAN or WLAN network.

[0053] In summary, the present invention provides a simple control method for a thermal energy distribution system, which uses temperature control at the heat sink side of the HRU to provide sufficient heat absorption capacity for the waste heat generation circuit, so that all waste heat appearing in the waste heat generation circuit can preferably be transferred to the heat consumption circuit and effectively utilized there to meet the thermal energy demand. Finally, it should be noted that the presented embodiments illustrate the concept of the present invention. The definitions of shape, form, connection or number are merely exemplary and may vary for different applications. However, as long as the concept of the present invention can still be implemented, all modifications within the knowledge of technicians in the relevant field are covered.

[0054] List of Reference Numerals

[0055]

Claims

1. A method for controlling the distribution of thermal energy in a commercial or industrial entity having a waste heat generation loop (10) connected to the primary side (21) of a heat exchanger (20), the secondary side (22) of the heat exchanger (20) being connected to a heat recovery unit (HRU) (30) at the heat source side (31) of the heat recovery unit (30), wherein a heat consumption loop (40) including at least one heat energy consumer (43) is connected to the heat sink side (32) of the heat recovery unit (30), wherein the method: A) determining a first temperature range of the fluid of the waste heat generation circuit (10) at the outlet (26) of the primary side (21) of the heat exchanger (20), within which the waste heat generation circuit (10) can be operated at an optimal energy efficiency ratio (EER) of the waste heat generation circuit (10); B) using the first temperature range and the heat exchange capacities of the heat exchanger (20) and the heat recovery unit (30), determining by calculation the temperature of the fluid of the heat consumption circuit (40) in the return line (42) to the heat recovery unit at a predetermined upper limit temperature (T max ) and the predetermined lower limit temperature (T min ) in the second temperature range (T R ), so that the waste heat generation circuit (10) can stably operate at its optimal energy efficiency ratio (EER); C) controlling the fluid temperature (T) and / or the return fluid flow rate in the return line (42) by controlling one or more flow valves (45) installed at at least one or more heat energy consumers (43), so that the temperature in the return line (42) to the heat recovery unit (30) does not exceed the predetermined upper limit temperature (T max ), nor does it drop below the predetermined lower temperature limit (T min ).

2. The method according to claim 1, wherein the heat consumption circuit (40) is a heating, ventilation and air conditioning (HVAC) circuit.

3. The method according to claim 1 or 2, wherein as long as the temperature (T) in the return line (42) remains within the temperature range (T R ), the temperature or flow rate through the return line (42) remains unchanged.

4. The method according to any one of claims 1 or 2, wherein when the temperature (T) in the return line (42) reaches or drops below the predetermined lower limit temperature (T min ), the flow through the return line (42) increases.

5. The method according to any one of claims 1 or 2, wherein when the temperature in the return line (42) reaches or exceeds the predetermined upper limit temperature (T max ), the flow rate (42) through the return line decreases.

6. The method according to any one of claims 1 to 5, wherein as long as the temperature in the return line (42) remains within a defined temperature range (T R ), the flow through the primary side (21) of the heat exchanger (20) can be adjusted according to the heat energy demand of the heat consumption circuit (40).

7. The method according to any one of claims 1 to 6, wherein the temperature at the inlet (25) of the heat exchanger (20) can be adjusted firstly according to the stable operation of the waste heat generating circuit (10) at the optimal energy efficiency ratio (EER) and secondly according to the heat demand of the heat consuming circuit (40).

8. The method according to any one of claims 1 to 7, wherein the temperature at the secondary side (22) of the heat exchanger (20) is adjusted firstly according to the stable operation of the waste heat generating circuit (10) with an optimal energy efficiency ratio (EER) of the waste heat generating circuit (10) and secondly according to the heat demand of the heat consumption circuit (40).

9. The method according to any one of claims 1 to 8, wherein the waste heat generation circuit (10) comprises a bypass line (17) bypassing the inlet (25) and the outlet (26) of the heat exchanger (10), wherein a three-way valve (18) combines the flows from the outlet (26) and the bypass line (17) such that the temperature in the waste heat generation circuit (10) downstream of the three-way valve (18) is maintained within the first temperature range.

10. The method according to claim 9, wherein the three-way valve (18) opens the bypass line (17) when the temperature of the waste heat generating circuit medium at the outlet (26) drops below a minimum temperature of the first temperature range.

11. The method according to any one of claims 1 to 10, wherein the waste heat generation circuit (10) comprises a cooler downstream of the outlet (26), the cooler being activated when the temperature of the waste heat generation circuit medium at the outlet (26) exceeds a maximum temperature of the first temperature range.

12. A thermal energy distribution system for a commercial or industrial entity, the thermal energy distribution system having a heat recovery unit (HRU) (30), a waste heat generation loop (10) connected to the heat recovery unit (30) at the heat source side (31) through a heat exchanger (20), a heat consumption loop (40) connected to the heat sink side (32) of the heat recovery unit (30), the heat consumption loop (40) having at least one or more thermal energy consumers (43) for providing thermal energy to the commercial or industrial entity, characterized in that: One or more temperature-controlled flow valves (45) are installed in the return line (42) of the at least one or more thermal energy consumers (43), wherein each flow valve (45) comprises a control unit (48) and a temperature sensor (47) for monitoring the temperature in the return line (42), wherein each control unit (48) is capable of commanding an actuator (46) of the flow valve (45), the actuator (46) being configured to open or close the corresponding flow valve (45) so that the temperature in the return line (42) does not exceed a predetermined upper limit temperature (T max ), nor does it drop below the predetermined lower temperature limit (T min ).

13. The thermal energy distribution system according to claim 12, wherein the predetermined upper limit temperature (T max ) and the predetermined lower limit temperature (T min ) can be set at the control unit (48) according to the waste heat generation circuit (10) being able to operate at an optimal energy efficiency ratio (EER) of the waste heat generation circuit (10).

14. The thermal energy distribution system according to claim 12 or 13, wherein the flow valve (45) is a pressure-independent flow valve or a pressure-dependent flow valve.

15. A thermal energy distribution system according to any one of claims 12 to 14, wherein the flow valve (45) is controlled in an on / off manner or in a regulating manner, and wherein the actuation of the flow valve (45) is analog controlled by 0-10V / 0-20mA current or digitally controlled by any communication protocol.

16. Thermal energy distribution system according to any one of claims 12 to 15, wherein the one or more control units (48) receive temperature limit values ​​from a building management system (BMS).

17. Thermal energy distribution system according to any one of claims 12 to 16, wherein the waste heat generation circuit (10) comprises: A bypass line (17) bypassing an inlet (25) and an outlet (26) located on the primary side (21) of the heat exchanger (10), wherein a three-way valve (18) combines flows from the outlet (26) and the bypass line (17) to the waste heat generation circuit (10) so that the waste heat generation circuit (10) can be operated at its optimal energy efficiency ratio (EER).

18. Thermal energy distribution system according to any one of claims 12 to 17, wherein the waste heat generation circuit (10) is a refrigeration circuit using CO2 or any other gas as refrigerant.

19. Thermal energy distribution system according to any one of claims 12 to 18, wherein the heat consumption circuit (40) is a heating, ventilation and air conditioning (HVAC) circuit.

20. A flow valve (45) for regulating flow through a fluid pipeline (42), comprising: a flow valve for a thermal energy distribution system, the flow valve being configured to be arranged in a return line of the thermal energy consumer, - an electromechanically operable actuator (46) configured to open and close a flow passage through the flow valve (45); - a temperature sensor (47), the temperature sensor (47) being used to monitor the temperature of the medium in the fluid pipeline (42); - a control unit (48) configured to set a predetermined upper limit temperature (T max ) and the predetermined lower limit temperature (T min ), and commanding the actuator (46) to open or close the flow channel; - a microcontroller in the control unit (48), the microcontroller being capable of: • receiving a temperature signal from the temperature sensor (47); • Determine whether the temperature signal indicates that the medium temperature is within a preset temperature range (T R ) and below the preset temperature range (T R ) or above the preset temperature range (T R ); • The temperature signal indicates that the medium temperature is below the temperature range (T R ), generates a valve opening command to the actuator (46), or • The temperature signal indicates that the medium temperature is above the temperature range (T R ) in the event of a valve closure, a valve closing command is generated to the actuator (46).

21. The flow valve (45) according to claim 20, wherein the control unit (48) further comprises a digital interface capable of receiving an external temperature range setting, temperature or command signal by wire or wirelessly.

22. The flow valve (45) according to claim 21, wherein the digital interface of the control unit (48) is also capable of receiving a predetermined upper temperature limit (T max ) value and the predetermined lower limit temperature (T min )value.

23. The flow valve (45) of claim 22, wherein the superior or supervisory control system is a building management system (BMS).

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