Apparatus and method for detecting faults and providing diagnostics in vapor compression cycle equipment

• US 7,079,967 B2
• Filed: 12/02/2003
• Issued: 07/18/2006
• Est. Priority Date: 05/11/2001
• Status: Expired due to Term

• Current Assignee: Mcloud Technologies (USA) Inc.
• Original Assignee: Field Diagnostic Services, Inc. (mCloud Technologies Corp.)
• Inventors: Rossi, Todd M., Douglas, Jonathan D., Rossi, Dale, Stockman, Timothy P.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Barbee, Manuel L.
• Application Number:
  US10/725,774
• Publication Number:
  US 20040111239A1
• Time in Patent Office: 959 Days
• Field of Search: 702/45, 702/47, 702/50, 702/55, 702 98-100, 702/113, 702/114, 702/130, 702/136, 702/138, 702/140, 702182-185, 621/29, 340/585
• US Class Current: 702/83
• 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 11/38 Failure diagnosis
• CPC Class Codes: F24F 11/54 using one central controller connected to several sub-controllers
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/19 Refrigerant outlet condenser temperature
• CPC Class Codes: F25B 2600/21 Refrigerant outlet evaporator temperature
• CPC Class Codes: F25B 2700/02 Humidity
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/195 of the condenser
• CPC Class Codes: F25B 2700/2106 of fresh outdoor air
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/21161 of the fluid heated by the condenser
• CPC Class Codes: F25B 2700/21163 of the refrigerant at the outlet of the condenser
• CPC Class Codes: F25B 2700/21172 at the inlet
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems

Abstract

An apparatus and method for detecting faults and providing diagnostic information in a refrigeration system comprising a microprocessor, a means for inputting information to the microprocessor, a means for outputting information from the microprocessor, and five sensors.

Claims

1. A method of providing diagnostics of a refrigeration system, the refrigeration system including a compressor, a condenser, an expansion device, and an evaporator connected together, the method comprising:

determining the type of expansion device used in the refrigeration system;

storing a plurality of HVAC system parameters that have been pre-defined for a particular refrigeration system and type of expansion device used;

defining a plurality of diagnostic messages based on said particular refrigeration system;

measuring at least five but not more than nine HVAC system variables;

calculating various HVAC operational variables including superheat based on the measurement of said at least five HVAC system variables;

comparing the calculated HVAC operational variables to said stored HVAC system parameters; and

conveying at least one of said plurality of diagnostic messages to a person performing said diagnostics;

wherein if it is determined during said determining step that said expansion device is a thermal expansion valve, the superheat is fixed at 20 °

F.

2. The method of claim 1 wherein said comparison step includes the assignment of a level based upon the relationship between said calculated HVAC operational variables and said stored HVAC system parameters.

3. The method of claim 2 wherein said levels assigned are “

LOW”

, “

BELOW GOAL”

, “

ABOVE GOAL”

, and “

HIGH”

, wherein a performance parameter is HIGH if its value is greater than the maximum operating limit;

a performance parameter is ABOVE GOAL if its value is less than the maximum limit and greater than the goal;

a performance parameter is BELOW GOAL if its value is less than the goal but greater than the low limit; and

a performance parameter is LOW if its value is less than the low limit.