METHOD FOR OPERATING AND/OR MONITORING AN HVAC SYSTEM

• US 20140222218A1
• Filed: 07/25/2012
• Published: 08/07/2014
• Est. Priority Date: 09/05/2011
• Status: Active Grant

• Current Assignee: Belimo Holding AG
• Original Assignee: Belimo Holding AG
• Inventors: Thuillard, Marc, D'silva, Vinod, Nightlinger, Mark, Aeberhard, Ronald
• Granted Patent: US 9,958,883 B2
• Time in Patent Office: Days
• US Class Current: 700/276
• CPC Class Codes: F24D 19/1048 Counting of energy consumption
• CPC Class Codes: F24D 2220/044 Flow sensors
• CPC Class Codes: F24F 2140/20 Heat-exchange fluid temperature
• CPC Class Codes: G01K 17/10 between an inlet and an outlet point, combined with measurement of rate of flow of the medium if such, by integration during a certain time-interval
• CPC Class Codes: G01K 2201/00 Application of thermometers in air-conditioning systems
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: G05D 23/1931 to control the temperature of one space

Abstract

The invention relates to a method for operating and/or monitoring an HVAC system (10), in which a medium circulating in a primary circuit (26) flows through at least one energy consumer (11, 12, 13), the medium entering with a volume flow (φ) through a supply line (14) into the energy consumer (11, 12, 13) at a supply temperature (T_v) and leaving the energy consumer (11, 12, 13) at a return temperature (T_R) via a return line (15), and transferring heat or cooling energy to the energy consumer (11, 12, 13) in an energy flow (E). A considerable improvement in the operating behavior of the system is achieved by empirically determining the dependence of the energy flow (E) and/or the temperature difference (ΔT) between supply temperature (T_v) and return temperature (T_R) on the volume flow (φ) for the energy consumers (11, 12, 13) in a first step, and by operating and/or monitoring the HVAC system (10) according to the determined dependency or dependencies in a second step.

Claims

1. A method for operating and/or monitoring an HVAC system (10), in which a medium, which circulates in a primary circuit (26), flows through at least one energy consumer (11, 12, 13), the medium entering at a volumetric rate of flow (φ

) into an energy consumer (11, 12, 13) through a supply line (14) at a supply temperature (T_V) and leaving the energy consumer (11, 12, 13) at a return temperature (T_R) by way of a return line (15) and, in so doing, releases heat energy or cold energy to the energy consumer (11, 12, 13) in a flow of energy (E), characterized in that the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_v) and the return temperature (T_R) on the volumetric flow rate (φ

) is determined empirically for the respective energy consumer (11, 12, 13) in a first step and that the HVAC system (10) is changed and/or operated in accordance with the determined dependence and/or dependences in a second step.

2. The method, as claimed in claim 1, characterized in that in order to determine empirically the dependence of the flow of energy (E) and/or temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

), while the system is running, over a sufficiently long period to time, the volumetric flow rate (φ

) and the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) are measured simultaneously at different points in time and, if desired, the associated flow of energy (E) is determined for each of these points in time from the associated measurement values and assigned to the respective volumetric rate of flow (φ

).

3. The method, as claimed in claim 1, characterized in that the dependence of the flow of energy (E) on the volumetric flow rate (φ

) is determined empirically, and that on the basis of the determined dependence, an upper limit value (E_max) of the flow of energy (E) is established, and this upper limit value is not exceeded while the HVAC system (10) is running.

4. The method, as claimed in claim 1, characterized in that the dependence of the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

) is determined empirically, and that on the basis of the determined dependence, a lower limit value (Δ

T_min) of the temperature differential AT between the supply temperature (T_V) and the return temperature (T_R) is established, and this lower limit value is not undershot while the HVAC system (10) is running.

5. The method, as claimed in claim 1, characterized in that the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

) is determined empirically at the start of the operation in a newly installed HVAC system (10), and that the continued operation takes place in accordance with the determined dependence and/or dependences.

6. The method, as claimed in claim 1, characterized in that the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

) is determined empirically at the start of the operation in a newly installed HVAC system (10), and that the HVAC system (10) or more specifically the individual components are changed or replaced, when the empirically determined dependences make it necessary.

7. The method, as claimed in claim 1, characterized in that the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

) is repeatedly determined empirically at longer time intervals, and that the results that are obtained in each case are compared with each other, in order to determine by means of the comparison a degradation of the system in function or effect.

8. The method, as claimed in claim 7, characterized in that the measurement values are scaled, in particular, by means of a mathematical model of the energy consumer (11, 12, 13) for purposes of comparison, or that other comparable measurements are used for comparison, when important operating parameters, such as the supply temperature (T_V), have changed significantly in the meantime.

9. The method, as claimed in claim 1, characterized in that first means (16, 17) for determining the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) as well as second means (18) for determining the volumetric flow rate (φ

) are provided in the HVAC system (10) for carrying out the operation, and that the first and second means (16, 17 and/or 18) are used for empirically determining the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

).

10. The method, as claimed in claim 9, characterized in that the empirical determination of the dependence of the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) on the volumetric flow rate (φ

) is carried out while the HVAC system (10) is running.

11. The method, as claimed in claim 1, characterized in that a control valve (19) is used for open and/or closed loop control of the volumetric rate of flow (φ

) in the primary circuit (26), and that the pressure differential (Δ

p) occurring at the control valve (19) is determined from the measured volumetric flow rate (φ

) in accordance with the characteristic curves of the control valve (19) and the valve position, and, if required, is used for controlling and/or monitoring purposes.

12. A HVAC system (10) for carrying out the method, as claimed in claim 1, said system comprising a primary circuit (26), which is traversed by the flow of an energy transporting medium, and at least one energy consumer (11, 12, 13), which is connected to the primary circuit (26) by way of a supply line (14) and a return line (15), wherein first means (16, 17) for determining the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) at the energy consumer (11, 12, 13) as well as second means (18) for determining the volumetric flow rate (φ

) through the energy consumer (11, 12, 13) are provided, characterized in that third means (21, 22) are connected to the first and second means (16, 17 and/or 18), and said third means (21, 22) receive and store the measurement values, which are outputted simultaneously by the first and second means (16, 17 and/or 18), at different times.

13. The HVAC system, as claimed in claim 12, characterized in that the third means (21, 22) comprise a data logger (22).

14. The HVAC system, as claimed in claim 12, characterized in that the third means (21, 22) are configured for calculating and assigning the flow of energy (E) from and/or to the measurement values outputted by first and second means (16, 17 and/or 18).

15. The HVAC system, as claimed in claim 12, characterized in that the HVAC system (10) includes a control unit (21), which controls and/or regulates by way of a control valve (19) the volumetric rate of flow (φ

) through the energy consumer (11, 12, 13) and into which the limit values (E_max, Δ

T_min) for the flow of energy (E) and/or the temperature differential Δ

T between the supply temperature (T_V) and the return temperature (T_R) can be entered.

16. The HVAC system, as claimed in claim 15, characterized in that the control unit (21) is connected to the first and second means (16, 17 and/or 18).

17. The HVAC system, as claimed in claim 12, characterized in that the first means (16, 17) comprise a first temperature sensor (16) for measuring the supply temperature and a second temperature sensor (17) for measuring the return temperature, and that the second means comprise a flowmeter (18), which is disposed in the supply line (14) or the return line (15) of the energy consumer (11, 12, 13).

18. The HVAC system, as claimed in claim 12, characterized in that the energy consumer (11, 12, 13) comprises a heat exchanger (11), by means of which energy is released to the secondary loop (27).