Refrigerant circulation device, refrigerant circulation method, refrigerant filling method, and method for operating refrigerant circulation device

Patent metadata

Field	Value
Publication number	US-10443899-B2
Application number	US-201615559598-A
Country	US
Kind code	B2
Filing date	Mar 28, 2016
Priority date	Mar 31, 2015
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

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.

First claim

The invention claimed is:

1. A refrigerant circulation method for use in a refrigerant circulation device having a compressor, a condenser, an expansion valve 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 a molecular structure thereof, wherein
the method comprises circulating the refrigerant with a desiccant that can trap moisture disposed in a location where an operating temperature of the refrigerant exceeds 0° C. but is less than 100° C.
a refrigerant supply pipe connected to the main pipe is a metal pipe, and
inside the refrigerant supply pipe is evacuated so that an amount of oxygen remaining in the refrigerant circulation circuit relative to an amount of refrigerant to be filled is less than 50 ppm (mass/mass), the refrigerant is subsequently used to fill the refrigerant circulation circuit, and the refrigerant is then circulated.

2. The refrigerant circulation method according to claim 1 , wherein
the evaporator is a shell and tube evaporator having a circular cylindrical container that houses the refrigerant, and a plurality of heat transfer tubes arranged inside the container, and
if a distance between a center of an uppermost heat transfer tube and a center of a lowermost heat transfer tube is deemed H, and a direction of gravity is deemed to be downward, then the desiccant is disposed inside the container within a region of ±H from a horizontal plane that includes a central axis of the uppermost heat transfer tube.

3. The refrigerant circulation method according to claim 1 , wherein the condensed refrigerant is guided through a filter dryer which is a filtration unit having the desiccant disposed therein, to a drive that drives the compressor, thereby cooling the drive.

4. The refrigerant circulation method according to claim 1 , wherein an acid acceptor that traps acid is disposed together with the desiccant.

5. The refrigerant circulation method according to claim 1 , wherein an aromatic-based or phenol-based antioxidant is added to a lubricating oil supplied to the refrigerant circulation device.

6. The refrigerant circulation method according to claim 5 , wherein the antioxidant is added to the lubricating oil in an amount of at least 0.2% by mass but not more than 1.5% by mass.

7. The refrigerant circulation method according to claim 1 , wherein an ether-based or epoxy-based acid acceptor is added to a lubricating oil supplied to the refrigerant circulation device.

8. The refrigerant circulation method according to claim 7 , wherein the acid acceptor is added to the lubricating oil in an amount of at least 0.2% by mass but not more than 3% by mass.

9. The refrigerant circulation method according to claim 7 , wherein an amount of the acid acceptor added to the lubricating oil is larger than an amount of an antioxidant.

10. The refrigerant circulation method according to claim 1 , wherein an acid value of a lubricating oil circulating in the refrigerant circulation device is measured, and the lubricating oil is replaced when the acid value of the lubricating oil exceeds 0.5 mgKOH/g.

11. The refrigerant circulation method according to claim 1 , wherein the refrigerant supply pipe is formed from a stainless steel.

12. The refrigerant circulation method according to claim 1 , wherein a condensing pressure and an evaporating pressure of the refrigerant are measured during operation, and the refrigerant is replaced when a measured value of at least one of the condensing pressure and the evaporating pressure falls outside a predetermined tolerance.

13. The refrigerant circulation method according to claim 1 , wherein a stereoisomer ratio is acquired that ensures that fluctuation ranges for a condensing pressure and an evaporating pressure of the refrigerant during operation fall within prescribed ranges, initial refrigerant filling is then performed at said stcrcoisomer ratio, and the refrigerant is then circulated.

14. A refrigerant circulation method for use in a refrigerant circulation device having a compressor, a condenser, an expansion valve 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 hydrochlorofiuoroolefin having a carbon-carbon double bond within a molecular structure thereof, wherein
the method comprises circulating the refrigerant with a desiccant that can trap moisture disposed in a location where an operating temperature of the refrigerant exceeds 0° C. but is less than 100° C., and
a stereoisomer ratio is acquired that ensures that fluctuation ranges for a condensing pressure and an evaporating pressure of the refrigerant during operation fall within prescribed ranges, initial refrigerant filling is then performed at said stereoisomer ratio, and the refrigerant is then circulated.

15. A refrigerant circulation method for use in a refrigerant circulation device having a compressor, a condenser, an expansion valve 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 a molecular structure thereof, wherein
the method comprises circulating the refrigerant with a desiccant that can trap moisture disposed in a location where an operating temperature of the refrigerant exceeds 0° C. but is less than 100° C.,
the evaporator is a shell and tube evaporator having a circular cylindrical container that houses the refrigerant, and a plurality of heat transfer tubes arranged inside the container, and
the desiccant is disposed inside the container within a region of ±H from a horizontal plane that includes a central axis of an uppermost heat transfer tube, H being deemed a distance between a center of the uppermost heat transfer tube and a center of a lowermost heat transfer tube, and a direction of gravity being deemed to be downward.

Assignees

• Mitsubishi Heavy Ind Thermal Systems Ltd
• Central Glass Co Ltd

Inventors

• Matsukura Noriyuki
• Ueda Kenji
• Kobayashi Naoki
• Suemitsu Ryosuke
• Horaguchi Norihisa
• Okamoto Satoru
• Nishiguchi Yoshio

Classifications

• C09K5/044

  comprising halogenated compounds · CPC title

• C09K2205/126

  Unsaturated fluorinated hydrocarbons · CPC title

• F25B2400/13

  Economisers · CPC title

• C09K5/04

  the change of state being from liquid to vapour or vice versa · CPC title

• C09K5/045

  containing only fluorine as halogen · CPC title