Abstract: It is an object of the present invention to provide a heat pump that can use, as a refrigerant, a substance with which a geometric isomer exists, and a method for designing the same. The present invention is a method for designing a heat pump (1) whose closed circuit configured by connecting a compressor (2), a condenser (3), an expansion valve (4), and an evaporator (5) in this order is filled with a refrigerant containing a refrigerant substance with which a geometric isomer may exist, the method including obtaining an upper limit of stable temperature at which isomerization of the refrigerant substance does not proceed, and setting an upper limit usage temperature of the heat pump (1) so as not to exceed the upper limit of the stable temperature.

Abstract: A compressor suction pipe includes a bent portion at least including a first pipe segment on the most upstream side with respect to flow of a fluid to be compressed, a second pipe segment connected to a suction side of a compressor and extending in a direction different from the extension direction of the first pipe segment, and a third pipe segment disposed between the first pipe segment and the second pipe segment and extending in a direction different from the extension directions of the first and second pipe segments, and at least one partition extending at least from an intermediate portion of the first pipe segment at least to an intermediate portion of the second pipe segment in the bent portion and dividing an interior of the bent portion. The partition extends in a direction intersecting a virtual plane including an incircle that touches an axis of the first pipe segment on an upstream side of a downstream end of the first pipe segment and touches an axis of the second pipe segment.

Abstract: The purpose of the present invention is to provide a compact heat exchanger with which the generation of excessive pressure loss can be suppressed and a suitable flow rate can be assured in accordance with the volumetric changes of a fluid due to phase changes. This heat exchanger (1) comprises a flow path (8) which has an inlet (10) into which a fluid (6) flows and an outlet (11) through which the flowed fluid (6) flows out, and in which a phase change from a fluid phase to a gas phase occurs between the inlet (10) and the outlet (11), wherein the inside of the flow path (8) is formed in a resistance shape (12) so that the amount of flow path resistance applied to the flow of the fluid (6) is smaller on the outlet (11) side than the inlet (10) side.

Abstract: A refrigeration machine control device according to an embodiment of the present invention serves to control a turbo refrigeration machine and is equipped with a pressure reduction rate identification unit for identifying a pressure reduction rate at which foaming does not occur in an oil tank, and a pressure adjustment unit for adjusting the pressure of an evaporator on the basis of the identified pressure reduction rate. The pressure reduction rate identification unit is equipped with: a refrigerant precipitation gas volume calculation unit for calculating the volume of refrigerant gas precipitated from lubricating oil when the pressure is reduced at a prescribed pressure reduction rate; and a determination unit for determining whether or not foaming is permissible on the basis of a comparison between the calculated volume and the volume on the surface of the oil in the oil tank.

Abstract: A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

Abstract: The present invention provides a control device for detecting an abnormal operation state of a compressor in a parallel refrigerator. The control device is a control device for a refrigerator that includes a plurality of compressors connected in parallel, and detects occurrence of surging and occurrence of droplet suction on the basis of a deviation between values of currents flowing through electric motors that is configured to drive each of the plurality of compressors, and an operation point indicated by the air volume and the compression ratio of the plurality of compressors.

Abstract: A refrigeration machine control device according to an embodiment of the present invention serves to control a turbo refrigeration machine and is equipped with a pressure reduction rate identification unit for identifying a pressure reduction rate at which foaming does not occur in an oil tank, and a pressure adjustment unit for adjusting the pressure of an evaporator on the basis of the identified pressure reduction rate. The pressure reduction rate identification unit is equipped with: a refrigerant precipitation gas volume calculation unit for calculating the volume of refrigerant gas precipitated from lubricating oil when the pressure is reduced at a prescribed pressure reduction rate; and a determination unit for determining whether or not foaming is permissible on the basis of a comparison between the calculated volume and the volume on the surface of the oil in the oil tank.

Abstract: The present invention is provided with: a turbo compressor that compresses a refrigerant; a condenser that condenses the refrigerant compressed by the turbo compressor; an expansion valve that expands a liquid refrigerant introduced from the condenser; an evaporator that evaporates the refrigerant expanded by the expansion valve; an oil tank that stores a lubricating oil supplied to the turbo compressor; a pressure equalizing pipe that connects the oil tank and the evaporator; and a control unit that controls start-up. The control unit calculates the amount of a refrigerant eluded into the lubricating oil in the oil tank at the time of start-up, and reduces a pressure reduction speed in the oil tank by limiting the opening operation of an IGV when the refrigerant elution amount per prescribed time exceeds a prescribed value.

Abstract: The objective of the present invention is to provide a refrigerant circulation device and a refrigerant circulation method with which a change in pressure inside the device can be avoided and performance stability and stable operation are achieved even when a HFO or a HCFO refrigerant is used. In the refrigerant circulation device (1), a refrigerant circulation circuit for circulating a refrigerant is formed by connecting a compressor (3), a condenser (5), an expansion valve (7), and an evaporator (9) through primary pipes (11a, 11b, 11c, 11d), and the refrigerant circulation circuit is charged with a refrigerant containing hydrofluoroolefin or hydrochlorofluoroolefin having a carbon-carbon double bond in the molecular structure.

Abstract: It is an object of the present invention to provide a heat pump that can use, as a refrigerant, a substance with which a geometric isomer exists, and a method for designing the same. The present invention is a method for designing a heat pump (1) whose closed circuit configured by connecting a compressor (2), a condenser (3), an expansion valve (4), and an evaporator (5) in this order is filled with a refrigerant containing a refrigerant substance with which a geometric isomer may exist, the method including obtaining an upper limit of stable temperature at which isomerization of the refrigerant substance does not proceed, and setting an upper limit usage temperature of the heat pump (1) so as not to exceed the upper limit of the stable temperature.

Abstract: A compressor suction pipe includes a bent portion at least including a first pipe segment on the most upstream side with respect to flow of a fluid to be compressed, a second pipe segment connected to a suction side of a compressor and extending in a direction different from the extension direction of the first pipe segment, and a third pipe segment disposed between the first pipe segment and the second pipe segment and extending in a direction different from the extension directions of the first and second pipe segments, and at least one partition extending at least from an intermediate portion of the first pipe segment at least to an intermediate portion of the second pipe segment in the bent portion and dividing an interior of the bent portion. The partition extends in a direction intersecting a virtual plane including an incircle that touches an axis of the first pipe segment on an upstream side of a downstream end of the first pipe segment and touches an axis of the second pipe segment.

Abstract: An object of the present invention is to provide a refrigerant circulation device and method that can suppress acid generation caused by decomposition of a refrigerant containing an HFO or HCFO. The refrigerant circulation device has a compressor, a condenser, expansion valves and an evaporator connected by a main pipe to form a refrigerant circulation circuit through which a refrigerant is circulated, the refrigerant circulation circuit being filled with a refrigerant containing a hydrofluoroolefin or a hydrochlorofluoroolefin having a carbon-carbon double bond within the molecular structure, wherein the refrigerant circulation device includes a drive that drives the compressor via a speed increaser, and a drive cooling unit that cools the drive with the refrigerant condensed in the condenser, and a desiccant that can trap moisture is disposed in the evaporator or the drive cooling unit.

Abstract: The present invention is provided with: a turbo compressor that compresses a refrigerant; a condenser that condenses the refrigerant compressed by the turbo compressor; an expansion valve that expands a liquid refrigerant introduced from the condenser; an evaporator that evaporates the refrigerant expanded by the expansion valve; an oil tank that stores a lubricating oil supplied to the turbo compressor; a pressure equalizing pipe that connects the oil tank and the evaporator; and a control unit that controls start-up. The control unit calculates the amount of a refrigerant eluded into the lubricating oil in the oil tank at the time of start-up, and reduces a pressure reduction speed in the oil tank by limiting the opening operation of an IGV when the refrigerant elution amount per prescribed time exceeds a prescribed value.

Abstract: An object of the present invention is to provide a heat source machine that can reduce the environmental load and can output the thermal energy with high temperature, and a method for operating the heat source machine. A heat source machine of the present invention includes a centrifugal compressor, condensers, expansion valves, and an evaporator, in which a refrigerant enclosed in a refrigerant circulation circuit configured by sequentially connecting the centrifugal compressor, the condensers, the expansion valves, and the evaporator contains a composition A, a composition B, or a composition C, the composition A has 4 or 5 carbon atoms, 6 or more fluorine atoms, and one or more oxygen atoms, the composition B has 4 or 5 carbon atoms and 6 or more fluorine atoms, the composition C has 3 carbon atoms, 2 chlorine atoms, 3 fluorine atoms, and an intramolecular double bond, and the composition A, the composition B, or the composition C has a boiling point of 20° C. or more and a critical temperature of 180° C.

Abstract: The object of the present invention is to suppress a mechanical loss caused by thermal elongation or rotational vibration of a rotary shaft of a turbo compressor for compressing a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG so as to enhance the efficiency of a turbo chilling apparatus. The turbo compressor is a turbo compressor for compressing a low pressure refrigerant used at a maximum pressure of less than 0.2 MPaG, the turbo compressor including: a rotary shaft; an electric motor coaxially disposed on an intermediate portion of the rotary shaft so a to rotationally drive the rotary shat impellers fixed to one end of the rotary shaft and forming a compression portion; a first bearing pivotally sporting the rotary shaft between the electric motor and the impellers; and a second bearing pivotally supporting the other end of the rotary shaft, wherein the first bearing is formed of a rolling bearing, and the second bearing is formed of a sliding bearing.

Abstract: An object of the present invention is to provide a refrigerant circulation device and method that can suppress acid generation caused by decomposition of a refrigerant containing an HFO or HCFO. The refrigerant circulation device has a compressor, a condenser, expansion valves and an evaporator connected by a main pipe to form a refrigerant circulation circuit through which a refrigerant is circulated, the refrigerant circulation circuit being filled with a refrigerant containing a hydrofluoroolefin or a hydrochlorofluoroolefin having a carbon-carbon double bond within the molecular structure, wherein the refrigerant circulation device includes a drive that drives the compressor via a speed increaser, and a drive cooling unit that cools the drive with the refrigerant condensed in the condenser, and a desiccant that can trap moisture is disposed in the evaporator or the drive cooling unit.

Abstract: A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.