US 6,668,564 B2Granted

Refrigeration cycle

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsTetsuji Saikusa, Hiroyuki Odagi, Naoki Tanaka

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Abstract

A highly reliable refrigeration cycle having a residual refrigerant, which is designed that the refrigerating machine oil does not stagnate in the refrigeration cycle after flowing out from the compressor even if the refrigerating machine oil is weakly soluble in a refrigerant. Thus, the compressor may be prevented from the exhaustion of oil. In addition to that, even if the accumulator is removed from the cycle, a large amount of wet vapor suction into the compressor may also be avoided. A control section is provided for controlling saturated oil solubility in a liquid refrigerant in the refrigeration cycle. The control section includes a receiver and first and second flow regulators which are placed before and after, respectively, the receiver. A residual liquid refrigerant obtaining in the circulation of a refrigerant is reserved in the receiver at a high temperature so that the weakly soluble refrigerating machine oil is prevented from separating.

Claims25

Dependent claims

A method for controlling a refrigeration cycle in which a compressor, an outdoor heat exchanger, a flow regulator, and an indoor heat exchanger are connected to each other via pipes to form a loop, the refrigeration cycle containing refrigerating machine oil and a refrigerant, the method comprising the step of:

controlling a saturation solubility of the refrigerating machine oil of a liquid refrigerant reserved in the refrigeration cycle via a control section so that the saturation solubility does not become lower than an oil circulation rate of the refrigerating machine oil in the refrigeration cycle;
positioning a receiver between the outdoor heat exchanger and the indoor heat exchanger in order for the receiver to reserve a residual refrigerant;
providing at least one of a first flow regulator between a first set of pipes which are connected with the receiver and the outdoor heat exchanger;
providing a second flow regulator between a second set of pipes which are connected with the receiver and the indoor heat exchanger;
detecting any one of temperature and pressure of the liquid refrigerant reserved in the receiver via a first detector;
and
controlling the one of the temperature and the pressure of the liquid refrigerant reserved in the receiver via a controller so that the saturation solubility of the refrigerating machine oil of the liquid refrigerant becomes any one of equal to and higher than the oil circulation rate of the refrigerating machine oil flowing in the refrigeration cycle, wherein the controller controls, during a given period from a start of the compressor, one of the first flow regulator and the second flow regulator so that a detected temperature of the liquid refrigerant in the receiver by the first detector becomes any one of equal to and higher than a given preset temperature.

4 more elements

A refrigeration cycle connecting a compressor, an outdoor heat exchanger, a flow regulator, and an indoor heat exchanger via pipes to form a loop, and containing refrigerating machine oil and a refrigerant, the refrigeration cycle comprising:

a control section for controlling a saturation solubility of the refrigerating machine oil of a liquid refrigerant reserved in the refrigeration cycle so that the saturation solubility does not become lower than an oil circulation rate of the refrigerating machine oil in the refrigeration cycle, the control section further including:
a receiver placed between the outdoor heat exchanger and the indoor heat exchanger, the receiver for reserving a residual refrigerant;
at least one of a first flow regulator, provided between a first set of pipes which are connected with the receiver and the outdoor heat exchanger, and a second flow regulator, provided between a second set of pipes which are connected with the receiver and the indoor heat exchanger;
a first detector for detecting one of temperature and pressure of the liquid refrigerant reserved in the receiver;
and
a controller for controlling the one of the temperature and the pressure of the liquid refrigerant reserved in the receiver so that the saturation solubility of the refrigerating machine oil of the liquid refrigerant becomes any one of equal to and higher than the oil circulation rate of the refrigerating machine oil flowing in the refrigeration cycle, wherein the controller controls, during a given period from a start of the compressor, one of the first flow regulator and the second flow regulator so that a detected temperature of the liquid refrigerant in the receiver by the first detector becomes any one of equal to and higher than a given preset temperature.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/061,275Filed 4 Feb 2002
Priority: JP 2001-07587216 Mar 2001
Published: US 2002/0129612 A119 Sep 2002
Granted: 30 Dec 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

F25B 49/022
For compression type machines, plants or systems: compressor control arrangements
F25B 31/002
Compressor arrangements: lubrication
F25B 49/025
For compression type machines, plants or systems: motor control arrangements
F25B 9/002
Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point: characterised by the refrigerant