REFRIGERATING AND AIR-CONDITIONING APPARATUS

• US 20120318011A1
• Filed: 03/12/2010
• Published: 12/20/2012
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Ochiai, Yasutaka, Unezaki, Fumitake
• Granted Patent: US 9,222,711 B2
• Time in Patent Office: Days
• US Class Current: 62/127
• CPC Class Codes: F25B 2400/13 Economisers
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2500/222 Detecting refrigerant leaks
• CPC Class Codes: F25B 2700/04 Refrigerant level
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

Each time an operation state indicated by operation data measured during normal operation of a refrigerating and air-conditioning apparatus meets an operation data acquisition requirement, the operation data is acquired, and a process of calculating the amount of refrigerant in parts other than an extension pipe and an extension-pipe density on the basis of the acquired data is performed. The internal volume of the extension pipe is calculated on the basis of a group of calculation data items indicating calculations by the process. A standard refrigerant amount is calculated on the basis of the calculated extension-pipe internal volume and the acquired data. The total refrigerant amount in the refrigerant circuit is calculated on the basis of the calculated extension-pipe internal volume and current operation data and is compared to the standard refrigerant amount, thus determining whether the refrigerant is leaked.

Claims

1. A refrigerating and air-conditioning apparatus comprising:

a refrigerant circuit in which an outdoor unit, serving as a heat source unit, and an indoor unit, serving as a use side unit, are connected by a refrigerant extension pipe;

a measurement section configured to measure, as operation data, a temperature and a pressure in each essential part of the refrigerant circuit;

a calculation section having an operation data acquisition requirement for acquiring operation data, the calculation section being configured to, each time an operation state indicated by operation data measured by the measurement section during normal operation meets the operation data acquisition requirement, acquire the operation data as initial learning operation data, perform a process of calculating an amount of refrigerant in parts other than the extension pipe and an extension-pipe density on the basis of the initial leaning operation data, calculate an internal volume of the extension pipe on the basis of a group of calculation data items indicating calculations by the process, and calculate a standard refrigerant amount, serving as a criterion for determination as to whether the refrigerant is leaked from the refrigerant circuit, on the basis of the calculated extension-pipe internal volume and the initial learning operation data;

a storage section configured to store the extension-pipe internal volume and the standard refrigerant amount; and

a determination section configured to calculate a total amount of refrigerant in the refrigerant circuit on the basis of the extension-pipe internal volume stored in the storage section and operation data measured by the measurement section during normal operation, and compare the calculated total refrigerant amount with the standard refrigerant amount stored in the storage section to determine whether the refrigerant is leaked.

2. The refrigerating and air-conditioning apparatus of claim 1, wherein the calculation section forms, on the basis of the group of calculation data items, an approximate expression indicating the relationship between the extension-pipe density and the refrigerant amount in the parts other than the extension pipe, and obtains the absolute value of the slope of the approximate expression as the extension-pipe internal volume.

3. The refrigerating and air-conditioning apparatus of claim 1,

wherein the extension pipe includes a liquid refrigerant extension pipe and a gas refrigerant extension pipe, and

wherein the calculation section multiplies a gas-refrigerant extension-pipe density, calculated on the basis of operation data, by a predetermined coefficient of a relational expression indicating that the internal volume of the gas refrigerant extension pipe is equal to the product of the internal volume of the liquid refrigerant extension pipe and the predetermined coefficient, and adds a liquid-refrigerant extension-pipe density, calculated on the basis of operation data, to the product of the gas-refrigerant extension-pipe density and the predetermined coefficient to obtain the extension-pipe density.

4. The refrigerating and air-conditioning apparatus of claim 1, wherein the calculation section determines, as a final calculation of the extension-pipe internal volume, the extension-pipe internal volume calculated using a group of calculation data items in which the difference between maximum and minimum values of the refrigerant extension-pipe density is greater than or equal to a certain value.

5. The refrigerating and air-conditioning apparatus of claim 1, wherein when the calculated extension-pipe internal volume lies within a range of predetermined upper and lower limits, the calculation section determines this extension-pipe internal volume as a final calculation of the extension-pipe internal volume.

6. The refrigerating and air-conditioning apparatus of claim 2, wherein the calculation section provides a predetermined range of data used for the formed approximate line, the range lying between upper and lower limits of the refrigerant amount in the parts other than the extension pipe, eliminates data outside the range to recalculate the approximate line, and determines, as a final calculation of the extension-pipe internal volume, the absolute value of the slope of the recalculated approximate expression.

7. The refrigerating and air-conditioning apparatus of claim 1, wherein the apparatus has a remote monitoring function for transmitting data indicating the presence or absence of refrigerant leakage to a control center through a communication line.

8. The refrigerating and air-conditioning apparatus of claim 1, wherein the operation data acquisition requirement includes a requirement in which fluctuations of each operation state are within a predetermined range, the operation states indicating the operating frequency of a compressor, the opening degree of an expansion valve, and the rotation speed of a fan attached to each of an indoor heat exchanger and an outdoor heat exchanger, the compressor, the expansion valve, and the indoor and outdoor heat exchangers serving as components of the refrigerating and air-conditioning apparatus.

9. The refrigerating and air-conditioning apparatus of claim 1, wherein the operation data acquisition requirement includes a requirement in which a value indicated by a high-pressure pressure sensor that detects the pressure of a high-pressure refrigerant in the refrigerant circuit is greater than or equal to a certain value, and a value indicated by a low-pressure pressure sensor that detects the pressure of a low-pressure refrigerant in the refrigerant circuit is less than or equal to a certain value.

10. The refrigerating and air-conditioning apparatus of claim 1, wherein the operation data acquisition requirement includes a requirement in which the width of fluctuations of the difference between a refrigerant temperature in an indoor heat exchanger in the indoor unit and an indoor temperature is within a predetermined range, and the width of fluctuations of the difference between a refrigerant temperature in an outdoor heat exchanger in the outdoor unit and an outdoor temperature is within a predetermined range.

11. The refrigerating and air-conditioning apparatus of claim 1, further comprising:

an output unit configured to transmit data indicating a result of determination by the determination section to an external device.