Field of the Invention

The present invention relates to a Heating, Ventilating and Air Conditioning HVAC field device, an HVAC system, a method of operating an HVAC field device and a computer program product for regulating a fluid flow in a fluid transportation circuit.

Background of the Invention

As people spend an estimated 90% of their time indoors, Heating, Ventilating and Air Conditioning HVAC systems have become of great importance to everyday life and have a great impact on people's health and comfort. In the field of Heating, Ventilating and Air Conditioning, HVAC systems typically comprise a fluid transportation system comprising one or more fluid transportation circuit (s), each connected to a heat exchanger arranged such as to be able to transfer thermal energy to I extract thermal energy from the environment to be controlled by means of a fluid circulating in said fluid transportation system. In order to be able to regulate the flow of fluid to/ from the heat exchanger and hence the amount of thermal energy transferred, the heat exchanger is connected to the fluid transportation system via one or more regulating devices, such as valves and dampers. The regulating devices are mechanically controlled by HVAC field devices, in particular actuators, including motorized HVAC actuators coupled to the regulating device(s). In the field of HVAC, HVAC actuators typically comprise an electric motor, drivingly coupled (through gears and/or other mechanical coupling), to the actuated part, i.e. the regulating device. HVAC actuators are electrically controlled by HVAC controllers, in particular an electronic circuit of HVAC controller(s). In addition, various HVAC sensors are used to measure environmental variables such as humidity, temperature, CO ₂ or dust particle levels Furthermore, HVAC sensors are used to determine operational parameters of various elements of an HVAC system, such as an actuated position of an actuated part, the

5 operational state of an HVAC actuator, e.g. online/ standby/ offline, operating temperature, error state, etc.

By regulating the flow of fluid through a thermal energy exchanger of an HVAC system, it is possible to adjust the amount of energy (respectively the amount of energy per unit of time, power) transferred by the thermal energy exchanger. For example, the energy0 exchange or the power transfer, correspondingly, is adjusted by regulating the amount of energy delivered to/ extracted from the thermal energy exchanger to heat or cool a room in a building, or by regulating the amount of energy delivered to a chiller for cooling purposes. While the fluid transport through the fluid transportation circuit of the HVAC system is driven by one or more pumps or fans, the flow is typically regulated by varying the orifice (opening) or position of valves.

The amount, efficiency and/or operational restrictions of the HVAC system such as efficiency of transfer of thermal energy by the thermal energy exchanger, the efficiency of thermal energy sources and/or flow regulating devices are often dependent on operational parameter(s) of the fluid transportation circuit, such as a flow rate; pressure; supply0 temperature and/or return temperature of thefluid through thefluid transportation circuit. For example, thermal energy is dissipated at a different rate, efficiency and is subject to different restrictions with respect to supply, respectively return temperature(s) than as it is the case for absorption of thermal energy. Summary of the Invention

It is an object of this invention to provide a Heating, Ventilating and Air Conditioning HVAC field device ( 10) for regulating a flow of a fluid, for example a liquid, e.g. water and/or a

5 refrigerant, or a gas, e.g. air, in a fluid transportation circuit (H, C) taking in consideration the dependency of the efficiency factors and/or operational restrictions of the HVAC system on operational parameter(s) of the fluid transportation circuit.

According to the present disclosure, this object is achieved by the features of independent claim 1 . In addition, further advantageous embodiments follow from the dependent claims0 and the description. In particular, this object is addressed by an HVAC field device for regulating a fluid flow in a fluid transportation circuit, in particular a fluid transportation circuit comprising a nd/or f I uid ica lly connectable to a heat exchanger, the HVAC field device comprising: a regulating device; a sensor device; and a controller configured to operate the regulating device in accordance with operational parameter(s) measured by the sensor device. The regulating device is arranged for regulating the fluid flow through the fluid transportation circuit, in particular by means of a control valve or a control damper. The sensor device is configured and arranged for measuring operational parameter(s) of the fluid transportation circuit, such as a flow rate, temperature and/or a pressure of the fluid through the fluid transportation circuit. 0 The controller is configured to operate the regulating device in a first energy transfer mode or in a second energy transfer mode in accordance with the operational parameter(s) measured by the sensor device. The first energy transfer mode is characterized by a first setpoint and the second energy transfer mode is characterized by a second setpoint, such as first respective second flow rate setpoint(s). The first respectively second setpoints (of the first and/or second operating mode) may comprise one or more ranges (such as closed end ranges, open-ended ranges and/or a combination of one or more closed end ranges), and/or discrete setpoint value(s) of one or more parameters.

5 Operating the regulating device in the first energy transfer mode or the second energy transfer mode comprises controlling the regulating device according to the first setpoint or the second setpoint.

Operating the regulating device in a first energy transfer mode or in a second energy transfer mode in accordance with the operational parameter(s) measured by the sensor0 device is advantageous as it allows adapting operation to the actual conditions of the fluid transportation circuit enabling efficient and proper operation. By defining specific setpoints of the operational parameter(s) of the fluid transportation circuit, one has the possibility to define sets of optimal operating conditions for a multitude of different uses of the same HVAC system.

The term 'HVAC field device' as used herein refers to a device hydraulically and/or mechanically connectable to at least part of fluid transportation circuit(s) with fluid supply/return lines, such as pipes, ducts or ports of valves and/or dampers such as to regulate and/or measure parameters of fluid(s) flowing therethrough, parameters such as flow rate, temperature, humidity, pressure, viscosity and/or chemical composition. 0 Alternatively, or additionally, HVAC field devices are connectable to other HVAC field device(s) such as to control and/or measure parameters thereof, such as valve position, as well as speed, current and voltage of actuator motor(s), as well as positions of flow regulating devices, such as valves and/or dampers, etc. HVAC field devices for regulating flow (parameters) of fluid(s) are referred to as HVAC actuators. HVAC actuators typically comprise a motor, such as an electric motor, and a mechanical drive for drivingly connecting the electric motor to an actuated part such as a valve or damper. HVAC actuators typically further comprise an interface for receiving

5 electrical power; control and/or configuration signals.

HVAC field devices for measuring parameters of fluid(s) are referred to as HVAC sensors. Furthermore, the term HVAC field device also encompasses HVAC field devices combining sensor and actuator functions, for both controlling and measuring parameters of fluid(s) or other HVAC field device(s). 0 According to embodiments disclosed herein, in the first energy transfer mode, thermal energy is dissipated (heating) by the fluid due to a decrease of the fluid's temperature along a direction of flow within the fluid transportation circuit, while in the second energy transfer mode, thermal energy is absorbed (cooling) by the fluid due to an increase of the fluid's temperature along a direction of flow within the fluid transportation circuit. The dissipation, respectively absorption of thermal energy is achieved in particular using a heat exchanger fluidically connected with the fluid transportation circuit through the regulating device.

According to embodiments disclosed herein, the sensor device comprises a flow sensor, the regulating device comprises or is drivingly connectable to a control valve or a control0 damper and the first setpoint and the second setpoint comprise a first flow rate setpoint and a second flow rate setpoint. The flow sensor is configured and arranged for measuring a flow rate of the fluid through the fluid transportation circuit. The control valve or control damper is configured and arranged for regulating the flow rate of the fluid through the fluid transportation circuit. In particular, the flow rate of the fluid is regulated by adjusting the dimensions of an orifice. As part of the control valve or control damper, the HVAC field device further comprises an actuator for actuating the control valve or the control damper, the controller being configured to generate control signals for driving the actuator. The control signals are generated in accordance with the first setpoint and the second setpoint

5 of the first respectively second energy transfer modes such as to bring and/ or maintain the flow rate of the fluid in the fluid transportation circuit measured by the sensor device at the first flow rate setpoint or second flow rate setpoint, respectively. Alternatively, the control signals are generated such as to minimize the difference between the flow rate measured by the sensor device and the first flow rate setpoint or second flow rate setpoint,0 respectively. According to embodiments where the setpoint defines a range(s), the control signals are generated such as to maintain the respective value within the range(s) defined by the setpoint.

For use in an HVAC system comprising two or more fluid transportation circuits, according to embodiments disclosed herein, the control valve is a 6-way valve comprising a first fluid input port , a second fluid input port, a fluid output port, a fluid return input port, a first fluid return output port and a second fluid return output port. The first fluid input port and the first fluid return output port are connectable to a supply line respectively a return line of a first fluid transportation circuit while the second fluid input port and the second fluid return output port are connectable to a second supply line respectively a second return line0 of a second transportation circuit. The fluid output port and the fluid return input port are fluidically connectable with a fluid input side respectively a fluid output side of a heat exchanger.

The controller is configured to control the regulating device such as to fluidically connect, in the first energy transfer mode, the first fluid input port with the fluid output port and the fluid return input port with the first fluid return output port. Thereby, in the first energy transfer mode, a heat exchanger - connectable to the fluid output port and the fluid return input port - is fluidically connected with the first supply line respectively a first return line of the fluid transportation circuit. Furthermore, in the first energy transfer mode, the

5 controller is configured to control the regulating device to bring and/ or maintain the flow rate of the fluid measured by the sensor device at the first flow rate setpoint in the fluid transportation circuit.

The controller is further configured to control the regulating device such as to fluidically connect, in the second energy transfer mode, the second fluid input port with the fluid0 output port and thefluid return input port with the second fluid return output port. Thereby, in the second energy transfer mode, a heat exchanger - connectable to the fluid output port and the fluid return input port - is fluidically connected with the second supply line respectively a second return line of the second fluid transportation circuit. Furthermore, in the second energy transfer mode, the controller is configured to control the regulating device such as to bring and/ or maintain the flow rate of the fluid measured by the sensor device at the second flow rate setpoint in the second fluid transportation circuit.

In an embodiment, the control valve for regulating the flow rate of the fluid is implemented as part of the 6-way valve, the 6-way valve achieving both the function of selectively connecting the fluid output port/ fluid return input port with the fluid transportation circuit0 or the second fluid transportation circuit, as well as function of regulating the flow rate therethrough. Alternatively, the regulating device comprises a control valve dedicated for regulating the flow rate as well as a separate 6-way valve dedicated for selectively connecting the fluid output port/ fluid return input port with the fluid transportation circuit or the second fluid transportation circuit. According to embodiments disclosed herein, the sensor device comprises and/or is connectable to a fluid pressure sensor for measuring a pressure of the fluid in the fluid transportation circuit. In particular, the fluid pressure sensor is configured and arranged for measuring a differential pressure between two sections of the fluid transportation

5 circuit, such as a pressure differential between a supply line and a return line of the fluid transportation circuit. Correspondingly, the first setpoint and the second setpoint comprise a first pressure setpoint and a second pressure setpoint. Based on the measurement of the pressure of the fluid in the fluid transportation circuit by the pressure sensor, the controller controls the regulating device such that the pressure of the fluid in the fluid transportation circuit measured by the sensor device is brought to/ maintained at the first pressure setpoint or second pressure setpoint, respectively. In particular, the pressure of the fluid is regulated by adjusting the opening of an orifice of the control valve or damper of the regulating device, thereby affecting the throughput and hence pressure at the fluid transportation circuit. 5 Alternatively, or additionally - according to embodiments disclosed herein, the sensor device comprises a supply temperature sensor for measuring a supply temperature of the fluid at a supply line of the fluid transportation circuit. In order to automate switching between the first and second energy transfer modes, the controller is configured to operate the regulating device in the first energy transfer mode or in the second energy transfer mode in accordance with the supply temperature of the fluid measured by the sensor device, in particular by comparison of the supply temperature of the fluid measured by the sensor device with a changeover temperature. For example, based on the supply temperature, the controller can automatically determine whether to operate the HVAC field device in a first energy transfer mode (e.g. heating) or a second energy transfer mode5 (e.g. cooling). According to embodiments disclosed herein, the controller is configured to introduce a delay period between operation of the regulating device in the first energy transfer mode and the second energy transfer mode. In particular, the controller is configured to control the regulating device such as to close or reduce the fluid flow below a lower threshold

5 during the delay period between the operation in the first energy transfer mode and the second energy transfer mode. For example, the regulating device is controlled such as to close off fluid flow for a delay period of 2 minutes between operation in a first energy transfer mode for dissipation of thermal energy (heating) and operation in the second energy transfer mode for absorbing thermal energy (cooling). 0 In addition to a supply temperature sensor, according to further embodiments disclosed herein, the sensor device comprises a return temperature sensor for measuring a return temperature of the fluid at a return port of the fluid transportation circuit. Correspondingly, the first setpoint and the second setpoint comprise a first temperature differential setpoint and a second temperature differential setpoint, the controller being configured to operate the regulating device in the first energy transfer mode or in the second energy transfer mode to bring and/or maintain a difference between the supply temperature and the return temperature as measured by the sensor device at the first temperature differential setpoint respectively the second temperature differential setpoint.

In particular, the controller is configured to control the flow of fluid using the regulating0 device such as to bring and or maintain the temperature differential between the supply temperature and return temperature - as measured by supply temperature sensor respectively the return temperature sensor - at the first temperature differential setpoint respectively the second temperature differential setpoint. For example, the controller is configured to maximize the temperature differential (between the supply temperature and return temperature) by regulating the flow rate of the fluid. Alternatively, the controller is configured to maintain a target temperature differential (between the supply temperature and return temperature) as a function of the supply temperature or the return temperature

Alternatively, or additionally, according to embodiments comprising a flow sensor and

5 both a supply and return temperature sensors, the first setpoint and second setpoint comprise first and second power transfer range(s). The controller is configured to determine a current power transfer by the fluid based on the measured flow rate as well as the temperature differential of the fluid (between the supply temperature and return temperature) and to control the regulating device such as to bring and/or maintain the0 current power transfer within the first respectively second power transfer range(s).

According to embodiments disclosed herein, the controller is configured to retrieve the first setpoint or the second setpoint in accordance with the first energy transfer mode, or the second energy transfer mode from a data storage. The data storage may be internal to the HVAC field device. Alternatively, or additionally, the data storage is communicatively connected to the HVAC field device.

According to further embodiments disclosed herein, the HVAC field device further comprises a communication interface configured for receiving a configuration command, the controller being configured to operate the regulating device in the first energy transfer mode or in the second energy transfer mode according to the configuration command0 received via the communication interface. The communication interface comprises one or more of: A wired communication interface (such as an Ethernet, in particular a Power over

Ethernet PoE, Single Pair Ethernet SPE, a BUS, in particular an MP Bus, BACnet, KNX or

Modbus interface);

A Wide Area Network communication circuit (such as GSM, LTE, 3G, 4G or 5G

5 mobile communications circuit);

A Low Power Wide Area Network (such as Narrowband Internet of Things NB-loT, Long Range LoRa/ LoRaWAN, SigFox, or Long Term Evolution Category M1 LTECatM l );

A local area network communication circuit (such as Wireless LAN);

A short range wireless communication circuit (such as Bluetooth, Bluetooth low0 energy BLE, Ultra-wideband UWB, Thread and/or Zigbee); and/ or

A close-range wireless communication circuit (such as Radio Frequency Identification RFID or a Near Field Communication NFC).

According to further embodiments, the communication interface is further configured for receiving the first setpoint or the second setpoint.

It is a further object of this invention to provide an HVAC system for regulating a fluid flow in a fluid transportation circuit taking in consideration the dependency of the efficiency factors and/or operational restrictions of the HVAC system on operational parameter(s) of the fluid transportation circuit. According to the present disclosure, this object is achieved by the features of independent claim 1 2. In addition, further advantageous embodiments0 follow from the dependent claims and the description. In particular, this object is addressed by an HVAC system comprising an HVAC field device according to one of the embodiments disclosed herein fluidically connected to a first thermal energy source and/or a second thermal energy source and a heat exchanger fluidically connected to the HVAC field device.

5 For fluidically connecting the HVAC field device with both the first thermal energy source and/or the second thermal energy source, according to further embodiments of the HVAC system, a 6-way valve comprising a first fluid input port, a second fluid input port, a fluid output port, a fluid return input port, a first fluid return output port and a second fluid return output port is provided as part of the regulating device. The first fluid input port and0 the first fluid return output port are connected to a supply line respectively a return line of the fluid transportation circuit connected to the first thermal energy source, while the second fluid input port and the second fluid return output port are connected to a second supply line respectively a second return line of a second transportation circuit connected to the second thermal energy source. The fluid output port and the fluid return input port are fluidly connected with a fluid input side respectively a fluid output side of a heat exchanger.

The controller is configured to control the 6-way valve such as to fluidically connect, in the first energy transfer mode, the first fluid input port with the fluid output port and the fluid return input port with the first fluid return output port. Thereby, in the first energy transfer mode, the heat exchanger is fluidically connected with the first supply line respectively a0 first return line of the fluid transportation circuit and hence with the first thermal energy source. Furthermore, in the first energy transfer mode, the controller is configured to control the regulating device to bring and/ or maintain the flow rate of the fluid measured by the sensor device at the first flow rate setpoint in the fluid transportation circuit. The controller is further configured to control the 6-way valve such as to fluidically connect, in the second energy transfer mode, the second fluid input port with the fluid output port and the fluid return input port with the second fluid return output port. Thereby, in the second energy transfer mode, the heat exchanger connected to the fluid output port and

5 the fluid return input port is fluidically connected with the second supply line respectively the second return line of the second fluid transportation circuit and hence to the second thermal energy source. Furthermore, in the second energy transfer mode, the controller is configured to control the regulating device such as to bring and/ or maintain the flow rate of the fluid measured by the sensor device at the second flow rate setpoint in the second0 fluid transportation circuit.

It is an even further object of this invention to provide a method of operating an HVAC field device for regulating a fluid flow in a fluid transportation circuit taking in consideration the dependency of the efficiency factors and/or operational restrictions of the HVAC system on operational parameter(s) of the fluid transportation circuit.

According to the present disclosure, this object is achieved by the features of independent claim 1 3. In addition, further advantageous embodiments follow from the dependent claims and the description. In particular, this object is addressed by a method of operating an HVAC field device, the method comprising: arranging a regulating device for regulating a fluid flow through a fluid transportation circuit; measuring operational parameter(s) of0 the fluid transportation circuit using a sensor device and operating, by a controller, the regulating device in the first energy transfer mode or in the second energy transfer mode (as described in preceding paragraphs above with respect to the device).

It is an even further object of this invention to provide a method of operating a computer program product for regulating a fluid flow in a fluid transportation circuit taking in consideration the dependency of the efficiency factors and/or operational restrictions of the HVAC system on operational parameter(s) of the fluid transportation circuit.

According to the present disclosure, this object is achieved by the features of independent claim 18. In addition, further advantageous embodiments follow from the dependent

5 claims and the description. In particular, this object is addressed by a computer program product comprising instructions, which, when executed by a controller of an HVAC field device, cause the HVAC field device to carry out the method according to one of the embodiments disclosed herein. 0 Brief Description of the Drawings

The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings show:

Figure 1 : a highly schematic block diagram of a first embodiment of an HVAC system 1 comprising an HVAC field device 10 for regulating a fluid flow through a fluid transportation circuit H in accordance with operational parameter(s) of the fluid transportation circuit H measured by a sensor device 30, fluidically connected to a heat exchanger 80;

Figure 2: a flowchart depicting steps of a first embodiment of a method of operating an0 HVAC field device 10 for regulating a fluid flow through a fluid transportation circuit H, C in accordance with operational parameter(s) of the fluid transportation circuit H, C measured by a sensor device 30,

Figure 3: a highly schematic block diagram of a further embodiment of an HVAC system 1 comprising an HVAC field device 10 for selectively regulating the fluid flow

5 in a first fluid transportation circuit H, and a second fluid transportation circuit C in accordance with operational parameter(s) of the fluid transportation circuits H, C measured by a sensor device 30;

Figure 4: a further highly schematic block diagram of the further embodiment of an HVAC system 1 comprising an HVAC field device 10 for selectively regulating0 the fluid flow in a first fluid transportation circuit H and a second fluid transportation circuit C in accordance with operational parameter(s) of the fluid transportation circuits H, C measured by a sensor device 30; and

Figure 5: a flowchart depicting steps of a further embodiment of a method of operating an HVAC field device 10 for selectively regulating the fluid flow in a first fluid transportation circuit H and a second fluid transportation circuit C in accordance with operational parameter(s) of the fluid transportation circuits measured by a sensor device 30.

Detailed Description

Reference will now be made in detail to certain embodiments, examples of which are0 illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

Whenever possible, like reference numbers will be used to referto like components or parts

Figure 1 shows a HVAC system 1 with a HVAC field device 10 for regulating a fluid flow in a fluid transportation circuit H, fluidly connectable to a heat exchanger 80 with fluid input

5 side 82 and fluid return side 84. The HVAC field device 10 comprises a regulating device 1 2; a sensor device 30; and a controller 20 configured to operate the regulating device 1 2 in accordance with operational parameter(s) measured by the sensor device 30. The regulating device 1 2 is arranged for regulating the fluid flow through the fluid transportation circuit H by means of a control valve 1 6. The sensor device 30 is configured0 and arranged for measuring operational parameter(s) of the fluid transportation circuit H, such as a flow rate F, temperature and/or a pressure of the fluid through the fluid transportation circuit H, using a flow sensor 32, a temperature sensor 34, (that might in particular be comprising a supply temperature sensor 34S and a return temperature sensor 34R) and/or a fluid pressure sensor 36. As part of the control valve 1 6, the HVAC field device 10 further comprises an actuator A for actuating the control valve 1 6, the controller 20 being configured to generate control signals for driving the actuator A. The supply line LS and the return line LR of fluid transportation circuit H are fluidically connected to a thermal energy source 100, such as a pump or fan.

According to embodiments, as shown on figure 1 with dotted lines, the HVAC field device0 10 further comprises a communication interface 14 configured for receiving a configuration command, the controller 20 being configured to operate the regulating device 1 2 in the first energy transfer mode or in the second energy transfer mode according to the configuration command received via the communication interface 14. The communication interface 14 may be accommodated by the sensor device 30, the regulating device 1 2 or it may be housed separately and communicatively connected with the controller 20.

Figure 2 shows a flowchart depicting steps of a first embodiment of a method of operating

5 an HVAC field device 10 for regulating a fluid flow through a fluid transportation circuit H, C.

In a first preparatory step S10, a regulating device 1 2 is arranged for regulating a fluid flow through a fluid transportation circuit H, C. The regulating device 1 2 may be arranged either at a supply line LS, LS _C , LS _H and/or at a return line LR, LR _C , LR _H of the fluid transportation0 circuit H, C and/or anywhere in-between. Thereafter, in a step S20, operational parameter(s) of the fluid transportation circuit H, C are measured using a sensor device 30 comprising or connectable to a sensor(s), such as a flow sensor 32, a temperature sensor 34 and/or a fluid pressure sensor 36.

In a step S30A, a first setpoint of a first energy transfer mode are retrieved from a data storage, while in a step S30B, a second setpoint of a second energy transfer mode are retrieved from a data storage, wherein each setpoint (of the first and/or second operating mode) may comprise one or more closed end ranges, one or more open-ended ranges of one or more parameters or discrete setpoint values, or a combination of one or more closed end ranges and one or more open-ended ranges of one or more parameters. The first0 setpoint and the second setpoint comprise one or more of: flow rate setpoint; pressure setpoint, in particular differential pressure setpoint; temperature setpoint; temperature differential setpoint and/or power setpoint. Thereafter, in steps S40A and S40B, the regulating device 1 2 is operated in the first energy transfer mode or in the second energy transfer mode, respectively, wherein operating the regulating device 1 2 in the first energy transfer mode or the second energy transfer mode comprises controlling the regulating device 1 2 according to the first setpoint or the second

5 set point.

Corresponding to the first setpoint of the first energy transfer mode, exemplified being linked to the transportation circuit H, step S40A of operating the regulating device 1 2, in the first energy transfer mode comprises one or more of:

In an alternative or cumulative substep S42A, generating control signals in0 accordance with the first setpoint of the first energy transfer mode such as to bring and/ or maintain the flow rate <t> of the fluid in the fluid transportation circuit H measured by a flow sensor 32 of the sensor device 30 at the first flow rate setpoint.

In an alternative or cumulative substep S44A, generating control signals in accordance with the first setpoint of the first energy transfer mode such as to bring and/ or maintain a difference between the supply temperature TS and the return temperature TR as measured by a supply temperature sensor 34S and a return temperature sensor 34R of the sensor device 30 at the first temperature differential setpoint respectively the second temperature differential setpoint.

In an alternative or cumulative substep S46A, generating control signals in0 accordance with the first setpoint of the first energy transfer mode such as to bring and/ or maintain the fluid pressure in the fluid transportation circuit H measured by a pressure sensor 36 of the sensor device 30 at the first fluid pressure setpoint. Corresponding to the second setpoint of the second energy transfer mode, exemplified being linked to the transportation circuit C, step S40B of operating the regulating device 1 2 in the second energy transfer mode comprises one or more of:

In an alternative or cumulative substep S42B, generating control signals in

5 accordance with the second setpoint of the second energy transfer mode such as to bring and/ or maintain the flow rate of the fluid in the fluid transportation circuit C measured by a flow sensor 32 of the sensor device 30 at the second flow rate setpoint.

In an alternative or cumulative substep S44B, generating control signals in0 accordance with the second setpoint of the second energy transfer mode such as to bring and/ or maintain a difference between the supply temperature TS and the return temperatureTR as measured by a supply temperature sensor 34S and a return temperature sensor 34R of the sensor device 30 at the second temperature differential setpoint respectively the second temperature differential setpoint.

In an alternative or cumulative substep S46B, generating control signals in accordance with the second setpoint of the second energy transfer mode such as to bring and/ or maintain the fluid pressure of the fluid in the fluid transportation circuit C measured by a pressure sensor 36 of the sensor device 30 at the second fluid pressure setpoint. 0 Figures 3 and 4 show highly schematic block diagrams of a further embodiment of an HVAC system 1 comprising an HVAC field device 10, for selectively regulating the fluid flow in a (first) fluid transportation circuit H (for heating) and a second fluid transportation circuit C (for cooling). For fluidically connecting the HVAC field device 10 with both the (first) thermal energy source 100 and the second thermal energy source 200, a 6-way valve 1 6' is provided as part of the regulating device 1 2. The 6-way valve 1 6' comprises a first fluid input port h, a second fluid input port l ₂ , a fluid output port O, a fluid return input port Rl, a first fluid return output port ROi and a second fluid return output port RO ₂ . The first fluid input port h and the first fluid return output port ROi are connected to a supply line l_S _H respectively a return line LR _H of the (first) fluid transportation circuit H connected to the thermal energy source 100, whilethe second fluid input port l ₂ and the second fluid return output port RO ₂ are connected to a second supply line LS _C respectively a second return line LR _C of a second transportation circuit C connected to the second thermal energy source 200. The fluid output port O and the fluid return input port Rl are fluidically connected with a fluid input side 82 respectively a fluid output side 84 of a heat exchanger 80.

In Figure 4, the (first) fluid transportation circuit H is depicted with continuous lines, while the second fluid transportation circuit C is depicted with dotted lines.

Figure 5 shows a flowchart depicting steps of a method of operating an HVAC field device 10 of figures 3 or 4 for selectively regulating the fluid flow in the (first) fluid transportation circuit H and the second fluid transportation circuit C in accordance with operational parameter(s) of the fluid transportation circuits H, C measured by the sensor device 30.

As illustrated in figure 5, in addition to the steps described in connection with figure 2, as part of step S40A of operating the regulating device 1 2 in the first energy transfer mode, in a substep S41 A, the 6-way valve 1 6' is controlled - by the controller 20 - such as to fluidically connect the firstfluid input port h with the fluid output port O and thefluid return input port Rl with the first fluid return output port ROi, thereby fluidically connecting the heat exchanger 80 with the first supply line l_S _H respectively a first return line LR _H of the (first) fluid transportation circuit H. In the first energy transfer mode, thermal energy is dissipated (heating) by the fluid due to a decrease of the fluid's temperature along a direction of flow at the (first) fluid transportation circuit H.

As part of step S40B of operating the regulating device 1 2 in the second energy transfer mode, in a substep S41 B, the 6-way valve 1 6' is controlled - by the controller 20 - such as to fluidically connect the second fluid input port l ₂ with the fluid output port O and the fluid return input port Rl with the second fluid return output port RO ₂ , thereby fluidically connecting the heat exchanger 80 with the second supply line LS _C respectively the second return line LR _C of the second fluid transportation circuit C. In the second energy transfer mode, thermal energy is absorbed (cooling) by the fluid due to an increase of the fluid's temperature along a direction of flow at the second fluid transportation circuit C.

Reference list

HVAC system 1

HVAC field device 10 regulating device 1 2

5 communication interface 14 control valve 1 6

6-way valve 1 6' controller 20 sensor device 30 flow sensor 32 temperature sensor 34, 34S, 34R fluid pressure sensor 36 heat exchanger 80 fluid input side (of heat exchanger) 825 fluid return side (of heat exchanger) 84 first thermal energy source 100 second thermal energy source 200 flow rate supply temperature TS return temperature TR fluid transportation circuit H, C supply line (of fluid transportation circuit) LS, LS _H , LS _C return line (of fluid transportation circuit) LR, LR _H , LR _C first fluid input port h5 second fluid input port l ₂ fluid output port O fluid return input port Rl first fluid return output port ROi second fluid return output port RO ₂