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US-12618583-B2 - Method, system and computer program product for controlling an HVAC system

US12618583B2US 12618583 B2US12618583 B2US 12618583B2US-12618583-B2

Abstract

A method of controlling a Heating, Ventilating and Air Conditioning (HVAC) system including a fluid transportation network that includes one or more network sections, each network section being connected to a fluid transportation circuit through respective supply lines and return lines, each network section including plural parallel zones, includes arranging a pressure regulating device in the supply lines and/or respective return lines of the network sections, arranging flow regulating devices in the zones of the network sections, measuring a remote differential pressure of the fluid in a first zone of the plurality of zones of each of the network sections, and controlling, by a controller, the pressure regulating devices of each network section to maintain the measured remote differential pressure within a specified differential pressure range.

Inventors

  • Markus Plasser
  • Christian Luchsinger

Assignees

  • BELIMO HOLDING AG

Dates

Publication Date
20260505
Application Date
20230616
Priority Date
20220808

Claims (16)

  1. 1 . A method of controlling a Heating, Ventilating and Air Conditioning (HVAC) system comprising a fluid transportation network that comprises one or more network sections, each network section being connected to a fluid transportation circuit through respective supply lines and return lines, each network section comprising a plurality of zones that are parallel, the method comprising: arranging a pressure regulating device in the supply lines and/or respective return lines of the network sections; arranging flow regulating devices in the zones of the network sections; arranging a pressure sensor for measurement of a remote differential pressure in a first zone, the first zone having a highest fluid resistance among the plurality of zones within the respective network section of the one or more network sections; measuring a remote differential pressure of the fluid in the first zone of the plurality of zones of each of the network sections; and controlling, by a controller, the pressure regulating devices of each network section to maintain the measured remote differential pressure within a specified differential pressure range.
  2. 2 . The method according to claim 1 , wherein one or more of the flow regulating devices are pressure-invariant regulating devices configured to implement the respective zones as pressure independent branches of the respective network section.
  3. 3 . The method according to claim 2 , further comprising: determining a fluid resistance of each of plurality of zones within the respective network section; and determining the first zone with the highest fluid resistance amongst the plurality of zones within the respective network section based on the fluid resistance of each of plurality of zones.
  4. 4 . The method according to claim 3 , wherein determining a fluid resistance of each of the plurality of zones comprises one or more of: calculating the fluid resistance of the zones mathematically based on their geometries; setting one or more flow regulating devices arranged in one or more of the zones to their respective fully open setting and measuring a zone pressure in each of the plurality of zones for determining the first zone with highest fluid resistance amongst the plurality of zones within the respective network section; and/or successively closing the flow regulating devices in all but one selected zone of the plurality of zones of the network sections to determine a fluid pressure in the selected zone.
  5. 5 . The method according to claim 2 , wherein arranging pressure sensors for measurement of the remote differential pressure in the first zone comprises arranging the pressure sensors such as to measure a differential pressure between a zone supply line and a zone return line of the first zone.
  6. 6 . The method according to claim 2 , wherein arranging pressure sensors for measurement of the remote differential pressure in the first zone comprises arranging the pressure sensors such as to measure a differential pressure over the flow regulating device in the first zone.
  7. 7 . The method according to claim 1 , further comprising: measuring section flow rates using section flow sensors arranged in the supply lines or respective return lines of one or more of the network sections; and controlling, by the controller, the flow regulating devices in the first zones—having a highest fluid resistance amongst the plurality of zones—such as to maintain the section flow rates above a minimum flow rate.
  8. 8 . The method according to claim 1 , further comprising: measuring a section flow rate in the supply lines or respective return lines of each of the network sections using a section flow sensor arranged in the supply line and/or the return line of each of the network sections; arranging a bypass flow regulating device at a location of highest fluid resistance within the respective network section; and controlling, by the controller, the bypass flow regulating device such as to maintain the section flow rate above a minimum flow rate.
  9. 9 . The method according to claim 7 , further comprising: measuring a fluid temperature at the respective supply lines and/or return lines of each network section; and adjusting the minimum flow rate in accordance with the measured fluid temperature.
  10. 10 . The method according to claim 5 , further comprising compensating the specified differential pressure range by a pressure compensation value if a current position of the flow regulating device in the first zone is below a minimum opening threshold.
  11. 11 . The method according to claim 10 , further comprising determining the pressure compensation value based on an estimated differential pressure in a second zone having a second highest fluid resistance amongst the plurality of zones within the respective network section.
  12. 12 . The method according to claim 1 , further comprising: determining current positions of the flow regulating device of each of the zones, the current positions being indicative of opening of the respective flow regulating device at a given time; controlling, by the controller, a power level of fluid flow generators such as a pumping power of pumps of the fluid transportation circuit in accordance with the current positions.
  13. 13 . The method according to claim 12 , further comprising: determining, from the current positions of the flow regulating devices of each of the zones, a currently most open position corresponding to the largest valve opening and/or currently least open position corresponding to the smallest valve opening amongst the positions of the flow regulating devices of each of the zones; reducing the power level of the fluid flow generators if the most open position is below a lower opening limit and/or increasing the power level of the fluid flow generator if the currently least open position exceeds an upper opening limit.
  14. 14 . The method according to claim 13 , further comprising: arranging zone flow rate sensors in each of the zones of the network sections; measuring an actual flow rate through the respective zone using the zone flow rate sensors; disregarding, from determining the currently most open position, positions of the flow regulating devices arranged in zones where the actual flow rate is below a flow rate threshold.
  15. 15 . The method according to claim 1 , wherein one or more of the flow regulating devices are implemented as six-way valves configured to couple each zone alternatively to a first fluid transportation circuit or to a second fluid transportation circuit.
  16. 16 . A Heating, Ventilating and Air Conditioning (HVAC) system comprising: a fluid transportation network having one or more network sections, each network section being connected to a fluid transportation circuit through respective supply lines and return lines, each network section comprising a plurality of zones; a flow regulating device arranged in each of the zones of the network sections; a pressure regulating device arranged in the supply lines and/or respective return lines of each of the network sections; a pressure sensor for measurement of a remote differential pressure arranged in a first zone, the first zone having a highest fluid resistance amongst the plurality of zones within the respective network section of the one or more network sections; and a controller, wherein the HVAC system is configured to control the pressure regulating devices of each network sections to maintain the remote differential pressure, measured by the pressure sensor in the first zone, within a specified differential pressure range.

Description

CROSS-REFERENCE TO RELATED APPLICATION This Application is based on and claims priority from Swiss Application No. CH000934/2022, filed on Aug. 8, 2022, the contents of which being herein incorporate by reference in its entirety. FIELD OF THE INVENTION The present invention relates to a method of controlling a Heating, Ventilating and Air Conditioning HVAC system comprising a fluid transportation network having one or more network sections, each comprising a plurality of parallel zones accommodating a thermal energy exchanger. The present invention further relates to a Heating, Ventilating and Air Conditioning HVAC system comprising a fluid transportation network having one or more network sections, each comprising a plurality of parallel zones accommodating a thermal energy exchanger. The present invention further relates to a computer program product for a controller of an HVAC system. BACKGROUND OF THE INVENTION In the field of Heating, Ventilating and Air Conditioning, HVAC systems typically comprise a fluid transportation network comprising thermal energy exchanger(s) arranged such as to be able to transfer thermal energy to/extract thermal energy from the environment to be controlled (referred to hereafter as controlled environment) by means of a fluid circulating in said fluid transportation network. 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 energy 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. In order to be able to regulate the flow of fluid to/from the thermal energy exchanger and hence the amount of thermal energy transferred, thermal energy exchanger(s) are connected to the fluid transportation network via one or more flow 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 thereof. In addition, various sensors are used to measure environmental variables such as humidity, temperature, CO2 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 operational state of an HVAC actuator. Fluid transport networks often comprise one or more network sections, each network section being connected to a fluid transportation circuit through respective supply line(s) and return line(s), each network section comprising a plurality of parallel zones each comprising a consumer, such as a thermal energy exchanger. However, the consumers typically have different designs, meaning that they have different geometries of its flow chambers—and have different and/or varying flow volumes and/or throughput. In order to undertake a balanced and/or compensated distribution of the fluids to the consumers in such fluid transport networks and to control a fluid flow such as to control its temperature, the consumers are each configured with a compensation- or balancing organ, for example a flow regulating device, particularly a valve (for liquids) or a damper (for gaseous fluids), which can regulate the flow rate through the respective consumer at different valve/damper opening positions. Due to different characteristics of the consumers of the different sections of fluid transportation network and/or of the flow regulating devices in the various zones, there are different requirements of operational parameters to be met for each of the parallel zones. A common requirement to be met for each of the parallel zones within a network section of a fluid transportation network is the fluid pressure being maintained within a specified differential pressure range. The specified differential pressure range to be maintained is defined by an operational range of the regulating device(s), the thermal energy consumer and/or any other element within the respective parallel zone, in particular an optimal operational range. For example, pressure invariant regulating valves have a specific pressure range within which they a