SYSTEM AND METHOD FOR CONTROLLING A SYSTEM THAT INCLUDES VARIABLE SPEED COMPRESSOR

• US 20150337831A1
• Filed: 12/20/2013
• Published: 11/26/2015
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: Trane International Inc. (Trane Technologies plc)
• Original Assignee: Trane International Inc. (Trane Technologies plc)
• Inventors: ZHOU, John, CLANIN, Thomas J., VOORHIS, Roger J.
• Granted Patent: US 9,777,724 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/20 by changing the driving speed
• 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 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/65 for selecting an operating mode
• CPC Class Codes: F24F 11/67 Switching between heating and cooling modes
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 2110/00 Control inputs relating to air properties
• CPC Class Codes: F24F 2140/50 Load
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A system and method for controlling a system that includes a variable speed compressor are described. The method can provide improved accuracy in the control of a system, for example, a heating, ventilating, and air condition (HVAC) system that includes a variable speed compressor, and can reduce a compressor cycling frequency of the compressor when a required capacity is below a minimum capacity of the compressor.

Claims

1. A system, comprising:

a compressor having the following operational states;

a unit off state, a startup state, and a running state, and

a controller that is configured to

(a) determine a required capacity of a conditioned space;

(b) compare the required capacity determined in (a) with a minimum capacity of the compressor,

wherein if the required capacity determined in (a) is greater than the minimum capacity of the compressor, then

(c1) operate the compressor in the running state; and

wherein if the required capacity determined (a) is less than the minimum capacity,

(c2) cycle between each of the operational states based on the required capacity determined in (a).

2. The system of claim 1, further comprising a supply fan, wherein the compressor is a variable speed compressor, and the supply fan and the variable speed compressor are controlled simultaneously.

3. The system of claim 1, wherein operational state of the compressor further comprises a shutdown state, wherein in the unit off state, the compressor stays off at the off position so that the speed of the compressor is at 0 revolutions per second (rps), wherein in the startup state, the speed of the compressor ramps up at a constant rate from 0 rps until the speed reaches a startup speed of the compressor, wherein in the running state, the compressor is modulated between a minimum speed and a maximum speed, and wherein in the shutdown state, the compressor ramps down from the minimum speed to 0 rps.

4. The system of claim 1, wherein in the unit off state, the supply fan is off so that the speed of the supply fan is at 0 rps, wherein in the startup state, the supply fan operates at a minimum speed, wherein in the running state, the supply fan is modulated between a minimum speed and a maximum speed, and wherein the shutdown state, the supply fan operates at a minimum speed.

5. The system of claim 1, wherein the supply fan is a variable speed fan.

6. The system of claim 1, wherein the supply fan operates at a fixed speed.

7. The system of claim 1, wherein in (c2), a determination is made as to the operating state of the compressor.

8. The system of claim 1, wherein in (a), the required capacity is based on a current reading of a dry-bulb temperature of the conditioned space and a predetermined temperature of the conditioned space.

9. A method of controlling a heating, ventilating and air conditioning system that includes a compressor, the compressor having the following operational states:

a unit off state, a startup state, and a running state, the method comprising

(a) determining a required capacity of a conditioned space;

(b) comparing the required capacity determined in (a) with a minimum capacity of the compressor,

wherein if the required capacity determined in (a) is greater than the minimum capacity of the compressor, then

(c1) operate the compressor in the running state

wherein if the required capacity determined (a) is less than the minimum capacity of the compressor,

(c2) cycle between each of the operational states based on the required capacity determined in (a).

10. The method of claim 9, wherein the compressor and the supply fan are controlled simultaneously.

11. The method of claim 9, wherein the operational state of the compressor further comprises a shutdown state, wherein in the unit off state, the compressor stays off at the off position so that the speed of the compressor is at 0 revolutions per second (rps), wherein in the startup state, the speed of the compressor ramps up at a constant rate from 0 rps until the speed reaches a startup speed of the compressor, wherein in the running state, the compressor is modulated between a minimum speed and a maximum speed, and wherein in the shutdown state, the compressor ramps down from the minimum speed to 0 rps.

12. The method of claim 9, wherein in the unit off state, the supply fan is off so that the speed of the fan is at 0 rps, wherein in the startup state, the supply fan operates at a minimum speed, wherein in the running state, the supply fan is modulated between a minimum speed and a maximum speed, and wherein the shutdown state, the supply operates at a minimum speed.

13. The method of claim 9, wherein in (c2), a determination is made as to the operating state of the compressor.

14. The method of claim 9, wherein in (a), the required capacity is based on a current reading of a dry bulb temperature of the conditioned space and a predetermined temperature of the conditioned space.

15. (canceled)

16. A system, comprising:

a variable capacity compressor having the following operational states;

a unit off state, a startup state, and a running state, and

a controller that is configured to

(a) determine a required capacity of a conditioned space;

(b) compare the required capacity determined in (a) with a minimum capacity of the compressor,

wherein if the required capacity determined in (a) is greater than the minimum capacity of the compressor, then

(c1) operate the compressor in the running state; and

wherein if the required capacity determined (a) is less than the minimum capacity,

(c2) cycle between each of the operational states based on the required capacity determined in (a).