DEVICE AND METHOD FOR CONTROLLING OPENING OF A VALVE IN AN HVAC SYSTEM

• US 20140083673A1
• Filed: 10/18/2011
• Published: 03/27/2014
• Est. Priority Date: 11/17/2010
• Status: Active Grant

• Current Assignee: Belimo Holding AG
• Original Assignee: Belimo Holding AG
• Inventors: Thuillard, Marc, Adams, John S.
• Granted Patent: US 9,631,831 B2
• Time in Patent Office: Days
• US Class Current: 165/299
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• 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: F24F 3/06 characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units

Abstract

For controlling the opening of a valve (10) in an HVAC system (100) to regulate the flow φ of a fluid through a thermal energy exchanger (2) of the HVAC system (100) and adjust the amount of energy E exchanged by the thermal energy exchanger (2), an energy-per-flow gradient (A) is determined, and the opening of the valve (10) is controlled depending on the energy-per-flow gradient (A). The energy-per-flow gradient (A) is determined by measuring at consecutive points in time the flow φ₁, φ₂ through the valve (10), by determining the amounts of energy E₁, E₂ exchanged by the thermal energy exchanger (2) at these points in time, and by calculating the energy-per-flow gradient (B) from the flow φ₁, φ₂ and exchanged energy E₁, E₂. The energy-per-flow gradient (A) can be determined dynamically and is used as a basis for setting a slope threshold for the thermal energy exchanger (2) so that there is no need to store fixed threshold values.

$\begin{array}{cc}\frac{E}{\varphi }& \left(A\right)\\ \frac{E}{\varphi }=\frac{E_2-E_1}{{\varphi }_2-{\varphi }_1}& \left(B\right)\end{array}$

Claims

1. A method of controlling opening (S3) of a valve (10) in an HVAC system (100) to regulate the flow φ

of a fluid through a thermal energy exchanger (2) of the HVAC system (100) and adjust the amount of energy E exchanged by the thermal energy exchanger (2), the method comprising;

determining (S31) an energy-per-flow gradient

2. The method of claim 1, wherein determining (S31) the energy-per-flow gradient

3. The method of one of claim 1, wherein determining (S314) the amount of energy exchanged by the thermal energy exchanger (2) comprises measuring the flow φ

(S313) through the valve (10), determining (S3143) between an input temperature T_in of the fluid entering the thermal energy exchanger (2) and an output temperature T_out of the fluid exiting the thermal energy exchanger (2) a temperature difference Δ

T=T_in−

T_out and calculating (S3144), based on the flow φ

through the valve (10) and the temperature difference Δ

T, the amount of energy E=Δ

T·

φ

exchanged by the thermal energy exchanger (2).

4. The method of claim 1, further comprising measuring (S301) a transport energy E_T used to transport the fluid through the HVAC system (100);

determining (S302) the amount of energy E exchanged by the thermal energy exchanger (2);

determining (S303), based on the transport energy E_T and the amount of energy E exchanged by the thermal energy exchanger (2), an energy balance E_B=E−

E_T;

comparing (S304) the energy balance E_B to an efficiency threshold; and

controlling the opening of the valve (10) depending on the comparing.

5. The method of claim 1, wherein the opening of valve (10) is controlled (S3H) to regulate the flow φ

of the fluid through a heat exchanger of the HVAC system (100);

the energy-per-flow gradient

6. The method of claim 1, wherein the valve (10) is controlled (S3C) to regulate the flow φ

of the fluid through a chiller (5) of the HVAC system (100);

the energy-per-flow gradient

7. The method of claim 5, further comprising determining (S1) the slope threshold by determining (S11) the energy-per-flow gradient

8. The method of claim 1, further comprising calibrating (S2) control signal (Z) levels which are used to control an actuator (11) of the valve (10) for opening the valve (10), by setting (S21) the control signal (Z) to a defined maximum value for placing the valve (10) to a maximum opening position, reducing (S24) the value of the control signal (Z) to reduce the opening of the valve (10) while determining the energy-per-flow gradient

9. A control device (1) for controlling opening of a valve (10) in an HVAC system to regulate the flow φ

of a fluid through a thermal energy exchanger (2) of the HVAC system (100) and adjust the amount of energy E exchanged by the thermal energy exchanger (2), the control device (1) comprising;

a gradient generator (14) configured to determine an energy-per-flow gradient

10. The control device (1) of claim 9, wherein the gradient generator (14) is configured to calculate the energy-per-flow gradient

11. The control device (1) of claim 9, wherein the gradient generator (14) is configured to calculate the amount of energy E=Δ

T·

φ

exchanged by the thermal energy exchanger (2) from a measurement of the flow φ

through the valve (10), and a temperature difference Δ

T=T_in−

T_out determined between an input temperature T_in of the fluid entering the thermal energy exchanger (2) and an output temperature T_out of the fluid exiting the thermal energy exchanger (2).

12. The control device (1) of claim 9, wherein, for regulating the flow φ

of the fluid through a heat exchanger of the HVAC system (100), the control module (15) is configured to control the opening of the valve (10) by having the gradient generator (14) determine the energy-per-flow gradient

13. The control device (1) of claim 9, wherein, for regulating the flow φ

of the fluid through a chiller (5) of the HVAC system (100), the control module (15) is configured to control the opening of the valve (10) by having the gradient generator (14) determine the energy-per-flow gradient

14. The control device (1) of claim 12, wherein the control module (15) is further configured to determine the slope threshold by having the gradient generator (14) determine the energy-per-flow gradient

15. The control device (1) of claim 9, further comprising a calibration module (16) configured to calibrate control signal levels (Z) which are used to control an actuator (11) of the valve (10) for opening the valve (10), by setting the control signal (Z) to a defined maximum value for placing the valve (10) to a maximum opening position, reducing the value of the control signal (Z) to reduce the opening of the valve (10) while having the gradient generator (14) determine the energy-per-flow gradient