VALVE CONTROL IN AN HVAC SYSTEM WITH SENSORS

• US 20150176931A1
• Filed: 12/03/2014
• Published: 06/25/2015
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Belimo Holding AG
• Original Assignee: Belimo Holding AG
• Inventors: AEBERHARD, Ronald, THUILLARD, Marc, MAZENAUER, Philipp
• Granted Patent: US 9,921,011 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/32 Responding to malfunctions or emergencies
• CPC Class Codes: F24F 11/49 ensuring correct operation, e.g. by trial operation or configuration checks
• CPC Class Codes: F24F 11/83 by controlling the supply of heat-exchange fluids to heat-exchangers
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F28F 27/00 Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus control arrangements in general G05
• CPC Class Codes: G05B 2219/37333 Position of control valve and position of controlled actuator

Abstract

The present disclosure is directed towards a method of controlling opening of a valve (10) in an HVAC system (100). The method includes controlling the opening of the valve (10) according to a default control mode in dependence of a default sensor signal. The method further includes determining, while controlling the opening of the valve (10) according to the default control mode, whether the default sensor signal is faulty and switching, in case of the default sensor signal being faulty, to controlling the opening of the valve (10) according to a fallback control mode, with the opening of the valve (10) being controlled independently of the faulty sensor signal in the fallback control mode. The present invention is further directed towards a corresponding control device opening of a valve (10) in an HVAC system as well as a corresponding computer program product.

Claims

1. A method of controlling opening of a valve in an HVAC system to regulate the flow φ

of a fluid through a heat exchanger of the HVAC system, the method including;

controlling the opening of the valve according to a default control mode in dependence of a default sensor signal, the default sensor signal being indicative of at least one parameter of the HVAC system;

determining, while controlling the opening of the valve according to the default control mode, whether the default sensor signal is faulty;

switching, in case of the default sensor signal being faulty, to controlling the opening of the valve according to a fallback control mode, with the opening of the valve being controlled independently of the faulty sensor signal in the fallback control mode;

determining, while controlling the opening of the valve according to the fallback control mode, whether the previously faulty default sensor signal is non-faulty, and

switching back to controlling the opening of the valve according to the default control mode, in case of the default sensor signal being non-faulty.

2. The method according to claim 1, wherein the method further includes controlling the opening of the valve in the fallback control mode in dependence of a fallback sensor signal;

determining, while controlling the opening of the valve according to the fallback control mode, whether the fallback sensor signal is faulty; and

, in case of the fallback sensor signal being faulty, switching to controlling the opening of the valve according to a further fallback control mode, with the opening of the valve being controlled independently of the faulty fallback sensor signal in the further fallback control mode.

3. The method according to claim 1, wherein the default sensor signal includes a set of sensor sub-signals, the sensor sub-signals reflecting different parameters of the fluid flow of fluid through the heat exchanger.

4. The method according to claim 1, wherein the method further includes selecting the fallback control mode from a set of alternative fallback control modes.

5. The method according to claim 4, wherein the alternative fallback control modes establish, in combination with the default control mode, a control mode hierarchy;

and the method further includes selecting the fallback control mode as a highest-ranking available control mode.

6. The method according to claim 5, wherein the method further includes determining, while controlling the opening of the valve according to the fallback control mode, whether a higher ranking control mode is available, and, in case of a higher ranking control mode being available, switching to controlling the opening of the valve according to the higher-ranking control mode.

7. The method according to claim 1, wherein the default control mode is a power control mode, with an amount of energy per time, E, that is exchanged by the heat exchanger being controlled to a set point energy per time value in the power control mode.

8. The method according to claim 7, wherein the fallback control mode is a pressure-independent control mode, with the flow co being controlled to a setpoint flow value in the pressure-independent control mode.

9. The method according to claim 1, wherein the fallback control mode is a opening control mode, with the valve being controlled to a setpoint degree of valve opening in the opening control mode.

10. The method according to claim 1, wherein the default sensor signal includes at least one of:

a flow signal φ

*, the flow signal φ

* being indicative of the flow φ

; and

a temperature difference signal Δ

T*, the temperature difference signal Δ

T* being indicative of a temperature difference Δ

T=T_in−

T_out between a supply temperature T_in of the fluid entering the heat exchanger and a return temperature T_out of the fluid exiting the heat exchanger.

11. The method according to claim 1, wherein the valve is a six-way-valve to fluidicly couple an inlet side and an outlet side of the heat exchanger alternatively with a first fluidic circuit in a first default control mode or a second fluidic circuit in a second default control mode, and the method further includes:

selecting the default control mode as selected default control mode from the first default control mode and the alternative second default control mode;

switching, in case of the default sensor signal being faulty, to controlling the opening of the valve according to a first fallback control mode or an alternative second fallback control mode in dependence of the selected default control mode.

12. A control device for controlling opening of a valve in an HVAC system to regulate the flow φ

of a fluid through a heat exchanger of the HVAC system and adjust the amount of energy per time, E, that is exchanged by the heat exchanger, the control device being configured to operatively couple to at least one sensor for receiving a default sensor signal, the control device further including a processor, the processor being configured;

to control the opening of the valve according to a default control mode in dependence of the default sensor signal, the sensor signal being indicative of at least one parameter of the HVAC system;

to determine, while controlling the opening of the valve according to the default control mode, whether the default sensor signal is faulty;

to switch, in case of the default sensor signal being faulty, to controlling the opening of the valve according to a fallback control mode, with the opening of the valve being controlled independently of the faulty default sensor signal in the fallback control mode;

to determine, while controlling the opening of the valve according to the fallback control mode, whether the previously faulty default sensor signal is non-faulty, and

to switch back to controlling the opening of the valve according to the default control mode, in case of the default sensor signal being non-faulty.

13. The control device according to claim 12, wherein the at least one sensor includes at least one of a flow sensor, the flow sensor being configured to provide a flow signal φ

* the flow signal φ

* being indicative of the flow φ

, and a temperature difference sensor, the temperature difference sensor being configured to provide a temperature difference signal Δ

T*, the temperature difference signal Δ

T* being indicative of a temperature difference Δ

T=T_in−

T_out between a supply temperature T_in of the fluid entering the heat exchanger and a return temperature T_out of the fluid exiting the heat exchanger.

14. The control device according to claim 12, wherein the processor includes a sensor testing unit, the sensor testing unit being configured to determine whether the default sensor signal is faulty.

15. The control device according to claim 12, wherein the processor includes a control mode selection unit and at least two control signal generators operatively coupled to the control mode selection unit, wherein the control signal generators are configured to alternatively generate a control signal Z for an actuator, the actuator being operatively coupled to the valve for regulating the opening of the valve.

16. A computer program product including a non-transient computer readable medium having stored therein computer program code configured to direct a processor of a control device for controlling opening of a valve in an HVAC system to regulate the flow φ

of a fluid through a heat exchanger of the HVAC system and adjust the amount of energy per time, E, that is exchanged by the heat exchanger by;

controlling the opening of the valve according to a default control mode in dependence of a default sensor signal, the default sensor signal reflecting at least one parameter of the HVAV system;

determining, while controlling the opening of the valve according to the default control mode, whether the default sensor signal is faulty;

switching, in case of the default sensor signal being faulty, to controlling the opening of the valve according to a fallback control mode, with the opening of the valve being controlled independently of the faulty default sensor signal in the fallback control mode;

determining, while controlling the opening of the valve according to the fallback control mode, whether the previously faulty default sensor signal is non-faulty, and

switching back to controlling the opening of the valve according to the default control mode, in case of the default sensor signal being non-faulty.