Refrigeration equipment

Abstract

This technology provides a way to fill the refrigerant circuit with the appropriate amount of odor components. [Solution] The refrigeration device 1 has a refrigerant circuit 10, and tetrahydrothiophene, an odor component, is sealed in the refrigerant circuit 10 together with the refrigerant and refrigerant oil. The refrigeration device 1 calculates the amount of refrigerant that leaks from the refrigerant circuit 10 in 4 minutes at a leakage rate of 0.001 kg / h. leak1 [kg], the amount of odor components to be filled into the refrigerant circuit 10 is M od [kg], the amount of refrigerant oil to be filled is M oil [kg], the solubility of odor components in refrigerant oil is S oil [ppm by weight], the amount of refrigerant to be filled into the refrigerant circuit 10 is M ref [kg], the volume of the living space LS is V[m 3 ], the density of odor components is ρ[kg / m³] 3 When ] is set, it satisfies a specific equation (1).

Description

[Technical Field]

[0001] This disclosure relates to a refrigeration system. [Background technology]

[0002] Conventionally, refrigeration systems that use highly flammable refrigerants sealed in the refrigerant circuit are known as refrigerants with a low Global Warming Potential (GWP) value. In this type of refrigeration system, it is important to detect refrigerant leaks from the refrigerant circuit early and avoid refrigerant combustion.

[0003] Patent Document 1 discloses a refrigeration cycle device in which, in addition to the refrigerant, an odor component, which is a sulfur-based odorant, is sealed in the refrigerant circuit. When the refrigerant leaks from the refrigerant circuit, the odor component also leaks out, allowing people in the vicinity to recognize the abnormality and take necessary action. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 7162786 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, when filling a refrigerant circuit with odor components, there is a challenge in balancing the amount of odor component needed to avoid causing abnormalities in people by keeping the refrigerant leakage rate below the flammable range, with the amount needed to cause abnormalities in people by making the refrigerant leakage rate below the flammable range. For example, if a large amount of odor component is sealed in the refrigerant circuit, there is a concern that a person sensitive to odor components may perceive a small leak of refrigerant and odor component that does not fall within the flammable range as an abnormality and make an inquiry. Conversely, if only a small amount of odor component is sealed in the refrigerant circuit, there is a concern that a person insensitive to odor components may not perceive an abnormality even if the refrigerant leakage rate from the circuit falls within the flammable range.

[0006] Furthermore, the refrigerant oil used to lubricate the compressor tends to dissolve odor components more readily than the refrigerant itself. Therefore, determining the appropriate amount of odor components to fill the refrigerant oil was difficult, even considering the relationship between odor components and refrigerant oil.

[0007] This disclosure provides a technology that can fill a refrigerant circuit with an appropriate amount of odor components. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a refrigeration device having a refrigerant circuit, wherein tetrahydrothiophene, an odor component, is sealed in the refrigerant circuit together with the refrigerant and refrigerant oil, wherein the amount of refrigerant leaking from the refrigerant circuit in 4 minutes at a leak rate of 0.001 kg / h is M leak1 [kg], the amount of the odor component to be filled into the refrigerant circuit is M od [kg], the amount of refrigerant oil to be filled is M oil [kg], the solubility of the odor component in the refrigerant oil is S oil [ppm by weight], the amount of refrigerant to be filled into the refrigerant circuit is M ref [kg], the volume of the living space is V[m 3 ], the density of the odor component is ρ[kg / m³] 3 When ] is set, the following equation (1) is satisfied. Note that the unit of the left term in equation (1) is [volume ppb].

[0009]

number

[0010] According to the above, the refrigeration system can fill the refrigerant circuit with an appropriate amount of odor component by satisfying equation (1). In other words, even if a small leak that does not reach the flammable range occurs in the refrigerant circuit, the refrigeration system will fill it with an amount of odor component that will not cause any abnormality in people sensitive to the smell of tetrahydrothiophene. As a result, the refrigeration system can be optimized for operation, such as reducing inquiries to service companies.

[0011] Also, let the leakage amount of the refrigerant leaking from the refrigerant circuit for 4 minutes at a leakage rate of 3 kg / h be M leak2 [kg], the filling amount of the odor component into the refrigerant circuit be M od [kg], the filling amount of the refrigeration oil be M oil [kg], the solubility of the odor component in the refrigeration oil be S oil [weight ppm], the filling amount of the refrigerant into the refrigerant circuit be M ref [kg], the volume of the living space be V [m 3 , and the density of the odor component be ρ [kg / m 3 . In this case, the following formula (2) is satisfied. Note that the unit of the left term of formula (2) is [volume ppb].

[0012]

Equation

[0013] By satisfying formula (2) in this way, when a refrigerant leak occurs in the refrigerant circuit that enters the flammable range, the refrigeration device can design the filling amount of the odor component that can make even a person insensitive to the odor of tetrahydrothiophene, which is an odor component, feel something abnormal.

[0014] Also, when the rated cooling capacity is 2.0 kW or less, the volume of the living space is 56.5 m 3 or less.

[0015] Thereby, in a refrigeration device with a rated cooling capacity of 2.0 kW or less, the filling amount of the odor component can be appropriately designed.

[0016] Also, when the rated cooling capacity exceeds 2.0 kW and is 2.5 kW or less, the volume of the living space is 21.8 m 3 to 70.6 m 3 or less.

[0017] Thereby, in a refrigeration device with a rated cooling capacity exceeding 2.0 kW and being 2.5 kW or less, the filling amount of the odor component can be appropriately designed.

[0018] Furthermore, if the rated cooling capacity exceeds 2.5 kW and is 3.5 kW or less, the volume of the living space is 27.3 m³. 3 ~98.8m 3 That is the case.

[0019] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 2.5 kW and 3.5 kW or less.

[0020] Furthermore, if the rated cooling capacity exceeds 3.5 kW and is 5.0 kW or less, the volume of the living space is 38.2 m³. 3 ~141.2m 3 That is the case.

[0021] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 3.5 kW and 5.0 kW or less.

[0022] Furthermore, if the rated cooling capacity exceeds 5.0 kW, the volume V of the living space is 54.5 m³. 3 That's all.

[0023] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 5.0 kW.

[0024] Furthermore, the refrigerant is a hydrocarbon-based refrigerant.

[0025] This allows the refrigeration system, in a configuration where hydrocarbon-based refrigerants are used to fill the refrigerant circuit, to optimize the amount of odor components being filled. [Brief explanation of the drawing]

[0026] [Figure 1] This diagram schematically shows the configuration of an air conditioning system according to an embodiment. [Figure 2] Figure 2(A) is a table showing a six-level odor intensity rating system. Figure 2(B) is a table showing evaluation items from a questionnaire regarding the perception of odor components. [Figure 3]This is a schematic diagram showing the test apparatus for odor sensory testing. [Figure 4] Figure 4(A) is a graph showing the relationship between odor intensity and how the odor is perceived. Figure 4(B) is a graph showing the relationship between the diffusion concentration of odor components and odor intensity. [Figure 5] Figure 5(A) is a table showing the odor intensity and diffusion concentration for people who are insensitive to the odor of odor components. Figure 5(B) is a table showing the odor intensity and diffusion concentration for people who are sensitive to the odor of odor components. [Figure 6] This is an example diagram showing the THT concentration distribution when refrigerant leaks from a stopped air conditioning system installed in a room at a leakage rate of 3 kg / h over 4 minutes. [Figure 7] This table explains the relationship between rated cooling capacity and the range of room volume. [Modes for carrying out the invention]

[0027] Hereinafter, embodiments for carrying out this disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted. In addition, dimensions, ratios, or numbers in each drawing may be exaggerated or simplified as necessary to facilitate understanding of the invention.

[0028] <Configuration of the refrigeration system> As shown in Figure 1, the refrigeration system 1 according to the embodiment of this disclosure is an air conditioning system that adjusts the temperature of the air in a living space LS. Hereinafter, the refrigeration system 1 will also be referred to as the air conditioning system 1. The air conditioning system 1 is used for cooling and heating operations of the living space LS by operating a vapor compression type refrigeration cycle. In cooling operation, the air conditioning system 1 cools the air in the living space LS to adjust its temperature. In heating operation, the air conditioning system 1 heats the air in the living space LS to adjust its temperature.

[0029] The air conditioning system 1 includes a refrigerant circuit 10 filled with refrigerant, an outdoor unit 20 which is a heat source unit installed in the outdoor space, and an indoor unit 30 which is a utilization unit installed in the living space LS. The refrigerant circuit 10 performs cooling and heating operations by circulating the refrigerant between the outdoor unit 20 and the indoor unit 30. The air conditioning system 1 according to this embodiment is a pair type in which one outdoor unit 20 and one indoor unit 30 are connected. However, the air conditioning system 1 may also be configured in which one outdoor unit 20 and multiple indoor units 30 are connected, or in which multiple outdoor units 20 and one indoor unit 30 are connected.

[0030] The refrigerant circuit 10 includes a first connecting pipe 11 and a second connecting pipe 12 that connect the outdoor unit 20 and the indoor unit 30. The first connecting pipe 11 and the second connecting pipe 12 connect the living space LS and the outdoor space and circulate the refrigerant. The first connecting pipe 11 is one or more gas pipes that circulate the refrigerant in gaseous form. The second connecting pipe 12 is one or more liquid pipes that circulate the refrigerant in liquid form.

[0031] Furthermore, the refrigerant circuit 10 has an outdoor route 13 inside the outdoor unit 20 that is connected to one end of the first connecting pipe 11 and one end of the second connecting pipe 12, respectively. In addition, the refrigerant circuit 10 has an indoor route 14 inside the indoor unit 30 that is connected to the other end of the first connecting pipe 11 and the other end of the second connecting pipe 12, respectively. The refrigerant circuit 10 forms an endless circulation circuit with the first connecting pipe 11, the second connecting pipe 12, the outdoor route 13, and the indoor route 14.

[0032] <Outdoor unit> The outdoor unit 20 constitutes a part of the refrigerant circuit 10 by having an outdoor passage 13 installed inside the housing 20a. The outdoor unit 20 includes a compressor 21, an outdoor heat exchanger 22, an expansion valve 23, a four-way switching valve 24, and an outdoor fan 25. The compressor 21, outdoor heat exchanger 22, expansion valve 23, and four-way switching valve 24 are connected to the outdoor passage 13 of the outdoor unit 20.

[0033] In refrigeration cycle operation, the compressor 21 compresses the low-pressure refrigerant drawn in from the suction connection terminal 21i to a high pressure and discharges the high-pressure refrigerant from the discharge connection terminal 21o. As the compressor 21, for example, a rotary type device can be used that rotates a sealed compression element with a compressor motor 21m to pressurize the refrigerant. The suction connection terminal 21i and the discharge connection terminal 21o of the compressor 21 are connected to the four-way switching valve 24 through the outdoor passage 13.

[0034] The outdoor heat exchanger 22 is a heat source-side heat exchanger (condenser) that dissipates heat from the refrigerant by exchanging heat between the refrigerant circulating inside and the outdoor air during the refrigeration cycle operation in cooling operation. For example, a fin-and-tube type mechanism can be applied to this outdoor heat exchanger 22. The gas connection terminal 22G of the outdoor heat exchanger 22 is connected to the four-way switching valve 24 through the outdoor passage 13. The liquid connection terminal 22L of the outdoor heat exchanger 22 is connected to the expansion valve 23 through the outdoor passage 13.

[0035] The outdoor fan 25 blows outdoor air to the outdoor heat exchanger 22. For example, the outdoor fan 25 can be a propeller fan having a motor and propeller (not shown).

[0036] The expansion valve 23 is a pressure reducing device that reduces the pressure of the refrigerant flowing in through the outdoor passage 13 to lower its temperature. The expansion valve 23 can be an electronic valve or a temperature-sensitive valve that adjusts the opening of the internal flow path. The expansion valve 23 may also be installed in the indoor unit 30.

[0037] The four-way switching valve 24 reverses the flow of refrigerant in the refrigerant circuit 10 to selectively perform cooling and heating operations. This four-way switching valve 24 can be switched between a first state, shown by the solid line in Figure 1, and a second state, shown by the dashed line in Figure 1.

[0038] The four-way diverter valve 24 is provided with a first port 241, a second port 242, a third port 243, and a fourth port 244 to which multiple pipes constituting the refrigerant circuit 10 can be connected. The discharge connection end 21o of the compressor 21 is connected to the first port 241 of the four-way diverter valve 24 via the piping of the outdoor route 13. The gas connection end 22G of the outdoor heat exchanger 22 is connected to the second port 242 of the four-way diverter valve 24 via the piping of the outdoor route 13. The piping of the outdoor route 13 that connects to the first connecting pipe 11 is connected to the third port 243 of the four-way diverter valve 24. The third port 243 is connected to the gas connection end 31G of the indoor heat exchanger 31 via the first connecting pipe 11. The suction connection end 21i of the compressor 21 is connected to the fourth port 244 of the four-way diverter valve 24 via the piping of the outdoor route 13.

[0039] As shown by the solid line in Figure 1, the four-way diverter valve 24 can form a first state in which the first port 241 and the second port 242 are in communication, and the third port 243 and the fourth port 244 are in communication. In this first state, the four-way diverter valve 24 connects the discharge connection end 21o of the compressor 21 and the gas connection end 22G of the outdoor heat exchanger 22, while connecting the suction connection end 21i of the compressor 21 and the first connecting pipe 11 outside the outdoor unit 20. In this first state, based on the drive of the compressor 21, refrigerant flows from the first connecting pipe 11 into the outdoor path 13 of the outdoor unit 20. The refrigerant is compressed by the compressor 21 to a high pressure and moves to the outdoor heat exchanger 22 through the four-way diverter valve 24. The refrigerant releases heat in the outdoor heat exchanger 22 and is further depressurized in the expansion valve 23, becoming a low-pressure, low-temperature liquid, which then moves to the second connecting pipe 12. In other words, the air conditioning unit 1 can perform cooling operation by drawing in high-temperature refrigerant via the first connecting pipe 11 and sending low-temperature refrigerant to the indoor unit 30 via the second connecting pipe 12.

[0040] Furthermore, as shown by the dotted line in Figure 1, the four-way switching valve 24 can form a second state in which the first port 241 and the third port 243 are in communication, and the second port 242 and the fourth port 244 are in communication. In this second state, the four-way switching valve 24 connects the discharge connection end 21o of the compressor 21 to the first external connecting pipe 11 of the outdoor unit 20, while connecting the suction connection end 21i of the compressor 21 to the gas connection end 22G of the outdoor heat exchanger 22. In this second state, based on the drive of the compressor 21, refrigerant flows from the second connecting pipe 12 into the outdoor path 13 of the outdoor unit 20. The refrigerant moves to the outdoor heat exchanger 22 through the expansion valve 23, and then moves from the outdoor heat exchanger 22 to the compressor 21. The refrigerant is compressed in the compressor 21 to become a high-pressure, high-temperature gas, which then moves to the first connecting pipe 11 through the four-way switching valve 24. In other words, the air conditioning system 1 can perform heating operation by drawing in low-temperature refrigerant through the second connecting pipe 12 and sending high-temperature refrigerant to the indoor unit 30 through the first connecting pipe 11.

[0041] Furthermore, the outdoor passage 13 of the outdoor unit 20 can be divided into a gas line 13G, which mainly circulates the refrigerant that has turned into a gas, and a liquid line 13L, which mainly circulates the refrigerant that has turned into a liquid. The gas line 13G is the passage that connects from the connection point with the first connecting pipe 11 to the compressor 21 and the gas connection terminal 22G of the outdoor heat exchanger 22. The liquid line 13L is the passage that connects from the connection point with the second connecting pipe 12 to the expansion valve 23 and the liquid connection terminal 22L of the outdoor heat exchanger 22.

[0042] A first shut-off valve 41 is provided at the connection point between the gas line 13G and the first connecting pipe 11. The first shut-off valve 41 opens and closes the flow path of the gas line 13G based on the operator's operation. A second shut-off valve 42 is provided at the connection point between the liquid line 13L and the second connecting pipe 12. The second shut-off valve 42 opens and closes the flow path of the liquid line 13L based on the operator's operation.

[0043] Furthermore, the first shut-off valve 41 has a gas service port 44. The second shut-off valve 42 has a liquid service port 45. The gas service port 44 is larger than the liquid service port 45. The gas service port 44 and the liquid service port 45 are used when filling the refrigerant circuit 10 of the air conditioner 1 with refrigerant, when releasing refrigerant from the outdoor unit 20, when measuring the pressure of the refrigerant in the refrigerant circuit 10, etc.

[0044] <Indoor unit> Meanwhile, the indoor unit 30 is installed in the living space LS. The indoor unit 30 constitutes a part of the refrigerant circuit 10 by having an indoor path 14 inside the housing 30a. The indoor unit 30 includes an indoor heat exchanger 31 and an indoor fan 32. The indoor heat exchanger 31 is connected to the indoor path 14 of the indoor unit 30.

[0045] The indoor heat exchanger 31 is a user-side heat exchanger (evaporator) that performs heat exchange between the refrigerant circulating inside and the indoor air during refrigeration cycle operation. As a result, the indoor heat exchanger 31 can cool the indoor air by absorbing heat from it when the refrigerant is at a lower temperature than the indoor air, and can warm the indoor air by releasing heat when the refrigerant is at a higher temperature than the indoor air. For example, a fin-and-tube mechanism can be applied to this indoor heat exchanger 31. The gas connection terminal 31G of the indoor heat exchanger 31 is connected to the first connecting pipe 11 through the indoor passage 14. The liquid connection terminal 31L of the indoor heat exchanger 31 is connected to the second connecting pipe 12 through the indoor passage 14.

[0046] The indoor fan 32 blows indoor air to the indoor heat exchanger 31. The indoor fan 32 is, for example, a cross-flow fan having a motor and a cylindrical impeller (not shown). The indoor air carried by the indoor fan 32 passes through the indoor heat exchanger 31 and is then blown from the indoor heat exchanger 31 into the living space LS.

[0047] Furthermore, the indoor unit 30 has a power circuit connected to the commercial power supply. The air conditioning system 1 operates the indoor unit 30 based on the power supply from the commercial power supply, and also operates the outdoor unit 20 via power lines (not shown).

[0048] <Control unit for air conditioning system> The air conditioning system 1 has a control unit 90 that controls the operation of each component. The control unit 90 is composed of a first control device 91, a second control device 92, and a remote controller 93. The remote controller 93 is a device that allows a person (user) to operate various instructions to the air conditioning system 1, and may be a dedicated controller or a mobile terminal such as a smartphone or tablet.

[0049] Each of the first control unit 91, the second control unit 92, and the remote controller 93 is a computer (specifically, an MCU: Micro Control Unit) having a processor, memory, input / output interface, and communication interface. The processor is a combination of one or more of the following: CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or a circuit consisting of multiple discrete semiconductors. The memory includes non-volatile memory and volatile memory. Programs that control various processes are stored in the memory, and the processor controls various operations by reading and executing the programs stored in the memory.

[0050] The first control device 91 is installed in the outdoor unit 20 and controls the various components of the outdoor unit 20. The second control device 92 is installed in the indoor unit 30 and controls the various components of the indoor unit 30. The first control device 91 and the second control device 92 can send and receive information from each other via wired or wireless communication. The second control device 92 and the remote controller 93 can send and receive information from each other via wired or wireless communication. The control unit 90 selectively performs cooling operation and heating operation in response to operation commands from a person (user) to the remote controller 93.

[0051] <Refrigerant> The refrigerant sealed in the refrigerant circuit 10 should be selected to have the lowest possible GWP value and low environmental impact. Examples of materials for this type of refrigerant include hydrocarbons (hydrocarbons) with 1 to 4 carbon atoms, such as R290 (propane), R1270 (propylene), and R600a (isobutane). These refrigerant materials are highly flammable refrigerants with higher flammability than hydrofluorocarbons. In this embodiment, the case where propane is used as the refrigerant will be described. Note that the refrigerant may also be methane (R50), ethane (R170), butane (R600), ammonia (R717), etc.

[0052] <Odor components> As previously mentioned, the air conditioning unit 1 contains an odor component along with the refrigerant in order to allow people to detect leaks of highly flammable refrigerant from the refrigerant circuit 10. This odor component could be, for example, tetrahydrothiophene (THT), a sulfur-based odorant that is a sulfur-based compound. Hereafter, tetrahydrothiophene may also be referred to as THT.

[0053] <Refrigerating machine oil> Furthermore, the air conditioning system 1 has refrigerant oil sealed in the refrigerant circuit 10 along with the refrigerant and THT. The refrigerant oil is mainly stored at the bottom of the compressor 21 within the refrigerant circuit 10 and circulated to the compression elements within the compressor 21 to maintain the lubrication of the sliding parts. In addition, a portion of the refrigerant oil circulates within the refrigerant circuit 10 together with the refrigerant and THT. In other words, the refrigerant oil is mixed with the refrigerant and THT and used as the working fluid for the refrigeration system. The ratio of refrigerant oil to the total amount of working fluid for the refrigeration system is preferably 10% by weight or more and 70% by weight or less, and more preferably 20% by weight or more and 60% by weight or less.

[0054] Examples of refrigeration oils include oxygen-containing synthetic oils (ester-based refrigeration oils, ether-based refrigeration oils, polyalkylene glycol oils, etc.) and hydrocarbon-based refrigeration oils. Among these, polyalkylene glycol oil (PAG oil) is preferred for hydrocarbon refrigerants from the viewpoint of compatibility. Refrigeration oils may be used individually or in combination of two or more types.

[0055] <Designing the amount of odor components to be filled> The above-described air conditioning system 1 can perform cooling and heating operations by filling and sealing the refrigerant circuit 10 with refrigerant and odor components during manufacturing at the factory, or by filling and sealing the refrigerant and odor components in the refrigerant circuit 10 by an operator after the system has been installed. As previously mentioned, there is a challenge in filling with odor components: it is difficult to balance the amount of odor components that should not be detected as abnormal by humans because the amount of refrigerant leakage does not fall into the flammable range, and the amount of odor components that should be detected as abnormal by humans because the amount of refrigerant leakage falls into the flammable range.

[0056] Therefore, in the air conditioning system 1 according to this embodiment, the amount of odor component (THT) to be filled is calculated using the following equations (1) and (2), and this calculated amount of THT is filled into the refrigerant circuit 10. The following describes the equations (1) and (2) used to set the amount of THT to be filled.

[0057]

number

[0058]

number

[0059] Equation (1) is a function for calculating the amount of THT (thoracic phosphate) that will not cause any adverse reactions in people sensitive to the odor of THT. The numerical value in the left term of Equation (1) represents the diffusion concentration [volume ppb] of THT, and is calculated based on the diffusion concentration setting method described below.

[0060] Also, M in equation (1) leak1 This constant represents the amount of refrigerant leakage when refrigerant and THT leak over a long period of time (slight leakage, slow leak) in a living space LS. In the case of slight refrigerant leakage, the entire amount will eventually leak out, but it will eventually be eliminated by ventilation of the living space. In the case of slight refrigerant leakage, there is sufficient margin for the creation of a flammable area. Therefore, when considering slight refrigerant leakage, it is advisable to set the value to one that does not cause inquiries about odor components from people sensitive to the smell of THT. Here, a typical cause of slight refrigerant leakage in a living space LS is ant nest corrosion in the tubes of the indoor heat exchanger 31. It is known that this ant nest corrosion of the indoor heat exchanger 31 has a leakage rate of approximately 0.001 kg / h.

[0061] Furthermore, the IEC standard (IEC60335-2-40), which specifies the safety of household and similar electrical appliances, regulates the amount of refrigerant leakage assuming the creation of a flammable area, and the leakage is conditional on a complete leak over 4 minutes. Therefore, M leak1 For this, it is best to set it to the amount of refrigerant [kg] that leaks from the refrigerant circuit 10 in 4 minutes at a leak rate of 0.001 kg / h. The actual amount of refrigerant that leaks in 4 minutes due to the corrosion of the ant nest is 0.0000667 kg.

[0062] M in equation (1) odThis variable (parameter) indicates the amount [kg] of odor component (THT) to be filled into the refrigerant circuit 10. The amount of THT to be filled into the refrigerant circuit 10 is this M od This will ultimately be calculated.

[0063] M in equation (1) oil This variable indicates the amount [kg] of refrigerant oil to be filled into the refrigerant circuit 10. oil This variable represents the solubility of THT in refrigerant oil [ppm by weight]. This solubility is a value that indicates the amount of THT that dissolves in a predetermined amount (e.g., 100g) of refrigerant oil. That is, a portion of the THT filled into the refrigerant circuit 10 dissolves into the refrigerant oil, while the rest of the THT evaporates or dissolves into the refrigerant. This solubility S oil This varies depending on the type of refrigerant oil. M in Equation (1) oil ×S oil This corresponds to the amount of THT dissolved in the refrigeration oil.

[0064] M in equation (1) ref This variable indicates the amount of refrigerant [kg] to be filled into the refrigerant circuit 10. According to the above IEC standard (IEC60335-2-40), the maximum amount of refrigerant to be filled into a household refrigeration system 1 using propane (R290) is approximately 1 kg. Therefore, the filling amount M ref The amount is set to a maximum of 1 kg.

[0065] In other words, (M in equation (1) od -M oil ×S oil ) / M ref The term refers to the amount of THT remaining after subtracting the amount of THT dissolved in the refrigerant oil, and the refrigerant charge amount M. ref This is the result of dividing by [a certain factor]. In other words, this term represents the concentration of odorants contained in refrigerant and THT leaks.

[0066] Furthermore, V in equation (1) is the volume of the living space LS corresponding to the rated cooling capacity set for each model of air conditioning unit 1 [m³ 3This is a variable that indicates [the cooling capacity]. The relationship between this rated cooling capacity and the volume of the living space LS will be described in detail later.

[0067] In equation (1), ρ is the gas density of the odor component [kg / m³]. 3 This value is determined by the type and composition of the odor components. If the odor component is THT, its density ρ is 3.66 [kg / m³]. 3 ]

[0068] By the way, the density of THT is 1.29 kg / m³, which is the density of air. 3 It is about three times higher than [ ], and the refrigerant density is 1.85 [kg / m³ 3 It is about twice as high as (R290). Furthermore, when the air conditioner 1 is stopped, the room is not stirred by the fan inside the air conditioner 1 as it is when it is running. In other words, especially when the air conditioner 1 is stopped, the THT that flows into the room along with the leaked refrigerant is less likely to diffuse than the refrigerant and is heavier than air, so it can be assumed that it will remain stagnant at the bottom of the room for a long time. Here, Figure 6 shows the results of a CFD analysis of the THT concentration distribution 4 minutes after the start of refrigerant leakage from the stopped air conditioner 1 (indoor unit 30) installed in the room. Note that in Figure 6, the whiter the gradient color, the lower the THT concentration, while the blacker the gradient color, the higher the THT concentration.

[0069] Figure 6 shows that a pool of THT concentration is observed in the lower part of the room, with a boundary layer of stagnation at approximately 1 / 4 of the room's height. People typically sit on the floor or chairs while working or lie down on bedding in a room, and the height where the stagnation occurs is where they can perceive the odor. Even when standing, their movements can provide a supplementary diffusion effect on the stagnant concentration. For these reasons, V is multiplied by a coefficient of 0.25 to calculate the appropriate concentration for a volume at 1 / 4 of the room's height.

[0070] On the other hand, equation (2) is a function for calculating the amount of THT (which is an odor component) that can be used to induce evacuation behavior in people who are insensitive to the smell of THT. The numerical value in the left term of equation (2) is a value that represents the diffusion concentration [volume ppb], similar to equation (1), and is a value calculated based on the diffusion concentration setting method described below.

[0071] M in equation (2) leak2 This constant represents the amount of refrigerant leaking in a short period of time in a living space (LS). When refrigerant leaks in a short period of time, it is advisable to set the value to a level that will prompt evacuation action by making even people insensitive to the smell of THT feel something is wrong due to THT before a flammable area is formed. As mentioned above, the IEC standard (IEC60335-2-40) requires a total leak within 4 minutes, and if a flammable area is formed by this total leak within 4 minutes, the ventilation effect cannot be expected. The leak rate when this flammable area is widely formed on the floor surface is 3 kg / h or more. Therefore, M leak2 This should be set to the amount of refrigerant [kg] that leaks from the refrigerant circuit 10 in 4 minutes at a leak rate of 3 kg / h. In this case, the leakage amount will be 0.2 kg.

[0072] Also, M in equation (2) od M oil S oil M ref V and ρ are constants or variables similar to those in equation (1) above.

[0073] From the above, equation (1) can calculate the amount of THT that will not cause complaints, etc., if a small amount of THT leaks, and a person sensitive to the smell of THT will not notice anything unusual. Equation (2) can calculate the amount of THT that will cause a person insensitive to the smell of THT to notice something unusual and prompt evacuation, if a large amount of THT leaks.

[0074] In equations (1) and (2), the amount of refrigerant M leaking from the refrigerant circuit 10 is... leak1 M leak2 These are different. Therefore, in reality, the amount of THT M that satisfies both equation (1) and equation (2) is odThe range can be calculated. Designers who fill and seal the refrigerant circuit with refrigerant and THT during manufacturing at the factory, or workers who fill the refrigerant and THT after the equipment has been installed, can calculate the amount of THT to be filled M derived from equations (1) and (2). od The amount of THT to be filled into the refrigerant circuit 10 is adjusted to fall within a certain range. This allows the air conditioner 1 to reduce the chances of a person sensitive to the smell of THT noticing an abnormality in the event of a small leak of refrigerant from the refrigerant circuit 10 that does not reach the flammable range. On the other hand, if a leak of refrigerant that reaches the flammable range occurs from the refrigerant circuit 10, the air conditioner 1 can make even a person insensitive to the smell of THT notice an abnormality and prompt them to take evacuation action.

[0075] <Regarding the diffusion concentration of odor components> Next, we will explain how to determine the numerical values ​​for the diffusion concentration [volume ppb] set in the left-hand term of equations (1) and (2) above. These diffusion concentration values ​​are obtained by the odor sensory test described below.

[0076] First, following the relationship between the concentration and odor intensity of 48 odor-causing substances (Research report commissioned by the Environment Agency, March 1980), we will determine the relationship between the concentration and odor intensity of tetrahydrothiophene (THT), an odor component. Odor intensity is one of the sensory tests that quantifies odor by focusing on the strength of the smell, and in Japan, the "6-level odor intensity display method" shown in Figure 2(A) is widely used. In the 6-level odor intensity display method, "odorless" is 0, "barely perceptible odor" is 1, "weak odor that can be identified" is 2, "easily perceptible odor" is 3, "strong odor" is 4, and "intense odor" is 5.

[0077] Furthermore, the "Olfactory Measurement Method Manual" supervised by the Ministry of the Environment states that the "Odor Intensity Survey Method" should be conducted by a supervisor and at least six judges (panel) as a sampling method similar to the measurement of the odor index, and also describes the judges' judgment methods and calculation methods. However, with judgments by only about six judges, the numerical values ​​are not stable and reproducibility cannot be obtained. For this reason, the "Olfactory Measurement Method Manual for Indoor Odors" published by the Architectural Institute of Japan states that the measurement value should be the one decimal place of the average value of data (n=18 or more) judged three times by at least six people. It also states that while the room entry method is preferable for judges, if the room entry method is difficult, judgments should be made by smelling odors prepared in an "odor bag".

[0078] Therefore, in the odor sensory evaluation, odor intensity is considered using a scoring method similar to that used in general sensory evaluations, with 0 representing no odor and 5 representing the maximum. Multiple evaluators are made aware that the categories shown in the table in Figure 2(A) are on an equally spaced scale on the questionnaire. However, misleading expressions such as "Can you identify the smell?" are avoided in the questionnaire. Furthermore, the number of evaluators is targeted at 18 or more, and the trimmed mean value, obtained by removing the maximum and minimum values, is calculated and rounded to the nearest 0.1 for the reported value.

[0079] In addition to odor intensity, the odor sensory test also asked participants to answer a questionnaire regarding their perception of the THT odor, as shown in Figure 2(B). The options for this questionnaire were: a) "There is an odor, but it is hardly noticeable"; b) "There is an odor, but it is the kind of everyday smell that I don't consider abnormal"; c) "I clearly smell an odor and would like to find the cause of the abnormality"; d) "The odor is strong and I would like to leave, but I can tolerate it for a short time and do not feel it is an emergency"; and e) "I feel that this is an abnormal situation requiring an emergency and I would like to escape immediately."

[0080] Furthermore, depending on the odor component, the results may differ depending on whether the assessment is made by smelling a gas with adjusted concentrations in a bag (i.e., by smelling it only with the nose) or by smelling the gas with the entire face. In this odor sensory test, the latter method was adopted instead of the former bag method, and each assessor placed their eyes, nose (face) against the opening of the chamber to judge the odor of THT. Specifically, a test apparatus 50 as shown in Figure 3 was used.

[0081] The test apparatus 50 uses a rectangular chamber 51 that is short in the horizontal direction (width and depth) but long in the vertical direction (height). The inside of this chamber 51 is a space 51s filled with THT. The chamber 51 is also equipped with an openable window 52 on one of its four vertically extending sides, allowing the evaluator to smell the odor of the space 51s inside the chamber 51 by opening the window 52 and bringing their face close.

[0082] Furthermore, the test apparatus 50 has multiple agitators 53 installed at the bottom of the chamber 51. Each agitator 53, for example, is equipped with a propeller in the space 51s of the chamber 51, and the gas filled in the space 51s is agitated by rotating this propeller at an appropriate rotational speed.

[0083] Furthermore, the chamber 51 has a filling port 51a for filling the space 51s with gas (including THT) and an extraction port 51b for extracting the gas filled in the space 51s. The filling port 51a is located near the bottom of the chamber 51. The extraction port 51b is located approximately in the middle of the vertical direction of the chamber 51. One end of a tube into which gas can be filled is connected to the filling port 51a. The other end of this tube is connected to a bag into which gas such as THT or a refrigerant is injected, and gas such as THT or a refrigerant is injected from this bag.

[0084] Furthermore, a sample collection bag is placed inside the vacuum chamber 56, and the extraction port 51b is connected to the opening of the sample collection bag through the vacuum chamber 56. A hose 54 for removing air from inside the vacuum chamber 56 is connected to the other end of the vacuum chamber 56, and a suction pump 55 is connected to the other end of the hose 54. By operating the suction pump 55 to reduce the pressure inside the vacuum chamber 56, the sample collection bag is caused to inflate by drawing in gas from the chamber space 51s.

[0085] The test apparatus 50 is basically configured as described above, and the method for conducting an odor sensory test using this test apparatus 50 will be explained below. In the odor sensory test, the above-mentioned chamber 51 is prepared, a tube is connected to the filling port 51a, and a vacuum box 56 containing a pre-vacuumed sample collection bag, as well as a hose 54 and a suction pump 55 are connected to the extraction port 51b (first step).

[0086] Then, in the odor sensory test, 10 μL or 100 μL of THT is injected into the bag and allowed to stand and vaporize at 60°C to prepare the THT gas (second step).

[0087] The stirring device 53 is operated to stir the space 51s in the chamber 51, and THT gas is introduced from the filling port 51a to adjust the initial concentration so that the odor intensity is approximately 1.5 to 2 (third step). For example, after introducing THT and stirring the space 51s with the stirring device 53, the stirring device 53 is stopped (left to stand) for 5 minutes to check the odor in the space 51s. After checking the odor, the process of adjusting and filling the THT again is repeated as needed.

[0088] Subsequently, in the odor sensory test, the stirring device 53 is stopped, the window 52 is opened each time, and the odor intensity is judged by multiple judges (for example, 18 to 22 people) (Step 4). The judges who have smelled the odor describe the degree of odor they perceived in a questionnaire.

[0089] Furthermore, in the odor sensory test, after each evaluator has completed their assessment, the concentration of THT filling the space 51s of the chamber 51 is increased, and the process returns to the third step, repeating the same adjustment and assessment as described above. For example, the stirring device 53 is operated to add more THT so that the concentration of THT in the space 51s becomes approximately three times higher, and then it is left to stand for at least 5 minutes. After this adjustment, the odor intensity is assessed again by multiple evaluators. The odor sensory test described above is terminated, for example, when the evaluators' assessment of odor intensity exceeds 4.

[0090] In the odor sensory test, after adjusting the concentration, the suction pump 55 is operated to reduce the pressure inside the vacuum box 56 before and after the judge begins his evaluation. This extracts the gas from space 51s through the extraction port 51b into a sample bag, and the gas from space 51s is analyzed using an analytical device (not shown). The analytical device measures the concentration of THT contained in the gas extracted from space 51s.

[0091] Upon examining the results of the questionnaires obtained from the above odor sensory tests, it was found that there was a very large variation in the odor intensity and perception of THT among the evaluators. However, a detailed analysis of the variation revealed that the coefficient of determination R in the normal probability plot was 2 The values ​​were approximately 0.9 or higher, indicating general normality. Therefore, the results of the THT questionnaire in the odor sensory evaluation were assumed to follow a normal distribution and analyzed accordingly.

[0092] Figure 4(A) is a graph showing the relationship between odor intensity and the perception of THT. Figure 4(B) is a graph showing the variation in THT diffusion concentration and odor intensity. The graph in Figure 4(A) shows the standard deviation calculated based on the results of a questionnaire on how evaluators perceive odors and the relationship with the odor intensity at that time, along with the median, +σ to +3σ, and -σ to -3σ. In the graph, the median is shown as a double circle. +σ to +3σ represents the spread of the normal distribution on the side where the odor intensity is greater than the median. +σ is a white circle in both graphs, +2σ is a black square in both graphs, and +3σ is a white square in both graphs. In other words, +σ to +3σ corresponds to the normal distribution of insensitive people who do not easily perceive odors even at high odor intensities. On the other hand, -σ to -3σ represents the spread of the normal distribution on the side where the odor intensity is smaller than the median. -σ is represented by a black circle in both graphs, -2σ by an open triangle in both graphs, and -3σ by a black triangle in both graphs. In other words, -σ to -3σ corresponds to the normal distribution of sensitive people who can easily detect odors even at low odor intensities.

[0093] As shown in Figure 4(A), sensory evaluation using the THT questionnaire did not show a correlation between odor intensity and perception, and there was also considerable variability among individuals. However, even people who are insensitive to THT would likely select option d of the questionnaire, "The smell is strong and I want to leave, but I can tolerate it for a short time and don't feel it's an emergency," if the odor intensity is 4 or higher. Conversely, even people who are sensitive to THT would likely select option c of the questionnaire, "I can clearly smell the odor and want to find the cause of the problem," if the odor intensity is 3 or lower.

[0094] Furthermore, as shown in Figure 4(B), when examining the normal distribution of THT diffusion concentration [volume ppb] and odor intensity, it can be said that the diffusion concentration regresses linearly as the odor intensity of THT increases. For example, the diffusion concentration from -σ to -3σ is lower than the diffusion concentration from +σ to +3σ, but the diffusion concentration increases linearly as the odor intensity of THT increases.

[0095] Here, the responses from the questionnaire regarding how people insensitive to THT might feel about taking evacuation action include d, "The smell is strong and I want to leave, but I can tolerate it for a short time and don't feel it's an emergency," and e, "I feel it's an emergency and an abnormal situation. I want to escape immediately." Even insensitive people will be prompted to leave if they recognize that the smell in the living space LS is strong. Here, the desirable scenario in the evacuation action is for people to take the necessary measures and evacuate safely themselves. In other words, if there is an abnormal smell, the desire to open the windows and ventilate is inevitable, and taking that measure eliminates the flammable area that has been created, thus removing the risk of subsequent ignition and explosion. Also, a psychological buffer is necessary for people of a wide range of ages to evacuate safely without panicking too much. Considering these points, we can expect actual evacuation action to occur when people feel d. When we extract the normal distribution of responses d from people insensitive to THT, we get the table in Figure 5(A). A value below +1σ of the median corresponds to a rating of d or e by 84.1% of the evaluators; a value below +2σ of the median corresponds to a rating of d or e by 97.7% of the evaluators; and a value below +3σ of the median corresponds to a rating of d or e by 99.85% of the evaluators.

[0096] Referring to Figures 4(A) and 4(B), when the odor intensity is within the range of +1σ of the median, the odor intensity is 4.2 or less, and the corresponding diffusion concentration is 40 [volume ppb] or less. Furthermore, when the odor intensity is within the range of +2σ of the median, the odor intensity is 4.5 or less, and the corresponding diffusion concentration is 82 [volume ppb] or less. When the odor intensity is within the range of +3σ of the median, the odor intensity is 4.8 or less, and the corresponding diffusion concentration is 170 [volume ppb] or less.

[0097] On the other hand, for people sensitive to THT, the perception that they do not recognize something as abnormal is thought to fall between option b, "There is an odor, but it is the kind of everyday smell and I don't think it is anything unusual," and option c, "I clearly smell an odor and want to find the cause of the abnormality." When we extract the normal distribution for people sensitive to THT who chose option c, we get the table shown in Figure 5(B). Below the median -1σ is the value where 15.9% of the judges judged option c, d, or e; below the median -2σ is the value where 2.3% of the judges judged option c, d, or e; and below the median -3σ is the value where 0.15% of the judges judged option c, d, or e.

[0098] Referring to Figures 4(A) and 4(B), when the odor intensity is within the range of -1σ of the median, the odor intensity is 2.5 or less, and the corresponding diffusion concentration is 1 [volume ppb] or less. Furthermore, when the odor intensity is within the range of -2σ of the median, the odor intensity is 2.0 or less, and the corresponding diffusion concentration is 0.17 [volume ppb] or less. When the odor intensity is within the range of -3σ of the median, the odor intensity is 1.5 or less, and the corresponding diffusion concentration is approximately 0.02 [volume ppb] or less.

[0099] If the design assumes a failure rate of 1 / 10 for evacuation actions being ineffective due to THT, then a normal distribution within ±1σ of the median should suffice, and a range of ±2σ would yield better results. Therefore, a THT diffusion concentration of 40 [volume ppb] or higher, and more preferably 82 [volume ppb] or higher, is desirable to encourage evacuation actions in less sensitive individuals. Conversely, a THT diffusion concentration of less than 1.0 [volume ppb], and more preferably less than 0.17 [volume ppb], is desirable to avoid causing sensitive individuals to perceive an anomaly.

[0100] Based on the results of the odor sensory tests described above, the value of the left term in equation (1) above can be set to 1.0, and the value of the left term in equation (2) above can be set to 40. In other words, a diffusion concentration [volume ppb] of less than 1.0 is desirable to avoid causing any abnormality in sensitive individuals. Furthermore, a diffusion concentration [volume ppb] of 40 or higher is desirable to prompt evacuation action in less sensitive individuals.

[0101] <Regarding the volume of living space> Next, we will explain the volume V of the living space LS, which is a variable in equations (1) and (2). The living space LS to which the air conditioning unit 1 is applied is selected according to its rated cooling capacity. In other words, the volume V of the living space LS changes based on the rated cooling capacity. The area of ​​the rated cooling capacity of the air conditioning unit 1 is the heat load [w / m 2 It depends on [the following]. In Japan, where the heat load is high, "HASS 109-1965" indicates a heat load of 145 w / m². 2 ~220w / m 2 It is set within this range. In Europe, on the other hand, although there are large differences depending on the region, in areas where air conditioning is frequently used, it is generally around 100 w / m². 2 Taking this as the moderate point for the thermal load, 85 W / m 2 ~125W / m 2 This is within the specified range. Furthermore, the height of the living space (LS) is approximately 2.4m.

[0102] The relationship between these heat loads and rated cooling capacity is summarized in the table shown in Figure 7. The table in the upper left of Figure 7 shows the range of rated cooling capacity in Japan and the upper and lower limits of the area of ​​the living space LS. Specifically, when the rated cooling capacity is 2.0 kW, the area of ​​the living space LS is 9.1 m². 2 ~13.8m 2 This falls within the range. If the rated cooling capacity is 2.5kW, the area of ​​the living space (LS) is 11.4m². 2 ~17.2m 2 This falls within the range. If the rated cooling capacity is 3.5kW, the area of ​​the living space (LS) is 15.9m². 2 ~24.1m 2 This falls within the range. If the rated cooling capacity is 5.0kW, the area of ​​the living space (LS) is 22.7m².2 ~34.5m 2 This falls within the range. If the rated cooling capacity is 10.0kW, the area of ​​the living space (LS) is 45.5m². 2 ~69.0m 2 This falls within the range of [the specified range].

[0103] Furthermore, the table in the lower left of Figure 7 shows the range of rated cooling capacity and the upper and lower limits of the living space area (LS) in Europe. Specifically, when the rated cooling capacity is 2.0 kW, the living space area (LS) is 16 m². 2 ~23.5m 2 This falls within the range. If the rated cooling capacity is 2.5kW, the area of ​​the living space LS is 20m². 2 ~29.4m 2 This falls within the range. If the rated cooling capacity is 3.5kW, the area of ​​the living space LS is 28m². 2 ~41.2m 2 This falls within the range. If the rated cooling capacity is 5.0kW, the area of ​​the living space LS is 40m². 2 ~58.8m 2 This falls within the range. If the rated cooling capacity is 10.0kW, the area of ​​the living space LS is 80m². 2 ~117.6m 2 This falls within the range of [the specified range].

[0104] From the above, the floor area of ​​the volume V of the living space LS applied to equations (1) and (2) should be set to the Japanese floor area (lower limit floor area) as the lower limit and the European floor area (upper limit floor area) as the upper limit, as shown in the table on the right of Figure 7. Then, by multiplying this floor area by the height of 2.4m, the lower limit (lower volume) and upper limit (upper volume) of the volume of the living space LS can be calculated. Specifically, when the rated cooling capacity is 2.0kW, the range from the lower limit volume to the upper limit volume of the living space LS is 21.8m 3 ~56.5m 3 This range applies. When the rated cooling capacity is 2.5kW, the range from the lower limit to the upper limit of the living space LS is 27.3m². 3 ~70.6m 3 This range applies. When the rated cooling capacity is 3.5kW, the range from the lower limit to the upper limit of the living space LS is 38.2m². 3~98.8 m 3 falls within the range. When the rated cooling capacity is 5.0 kW, the lower limit volume to upper limit volume range of the living room space LS is 54.5 m 3 ~141.2 m 3 falls within the range. When the rated cooling capacity is 10.0 kW, the lower limit volume to upper limit volume range of the living room space LS is 109.1 m 3 ~282.4 m 3 falls within the range.

[0105] More specifically, when the rated cooling capacity of the air conditioner 1 is 2.0 kW or less, the volume V of the living room space LS is preferably 56.5 m 3 or less. By using this volume V of the living room space LS, the THT can be filled with an appropriate filling amount for the air conditioner 1 with a rated cooling capacity of 2.0 kW or less.

[0106] Also, when the rated cooling capacity of the air conditioner 1 exceeds 2.0 kW and is 2.5 kW or less, the volume V of the living room space LS is preferably 21.8 m 3 ~70.6 m 3 By using this volume V of the living room space LS, the THT can be filled with an appropriate filling amount for the air conditioner 1 whose rated cooling capacity exceeds 2.0 kW and is 2.5 kW or less.

[0107] Also, when the rated cooling capacity of the air conditioner 1 exceeds 2.5 kW and is 3.5 kW or less, the volume V of the living room space LS is preferably 27.3 m 3 ~98.8 m 3 By using this volume V of the living room space LS, the THT can be filled with an appropriate filling amount for the air conditioner 1 whose rated cooling capacity exceeds 2.5 kW and is 3.5 kW or less.

[0108] Also, when the rated cooling capacity of the air conditioner 1 exceeds 3.5 kW and is 5.0 kW or less, the volume V of the living room space LS is preferably 38.2 m 3 ~141.2 m 3It is desirable that this be the case. By using the volume V of this living space LS, THT can be filled in an appropriate amount for an air conditioning unit 1 with a rated cooling capacity exceeding 3.5 kW and 5.0 kW or less.

[0109] Furthermore, if the rated cooling capacity of the air conditioning unit 1 exceeds 5.0 kW, the volume V of the living space LS is 54.5 m². 3 The above is desirable. By using the volume V of this living space LS, THT can be filled in an appropriate amount for an air conditioning unit 1 with a rated cooling capacity exceeding 5.0 kW.

[0110] As described above, the volume V of the living space LS in equations (1) and (2) can be used to determine the lower and upper limits of the volume corresponding to the rated cooling capacity of the air conditioning unit 1. Therefore, the amount of THT filling M that can be calculated based on equation (1) to avoid causing any abnormality in sensitive individuals is... od It can also be calculated using lower and upper limits corresponding to the range of lower and upper volumes. Similarly, the amount of THT filling M can be calculated based on formula (2) for prompting evacuation by making insensitive people feel something is wrong. od Furthermore, it can be calculated using lower and upper limits corresponding to the range of lower and upper volumes. Therefore, the filling amount M of THT that satisfies both equation (1) and equation (2) is od This is the filling amount M in equation (1). od The lower and upper limits, and the filling amount M in equation (2) od This is the range where the lower and upper limits overlap.

[0111] When filling the air conditioning unit 1 with refrigerant and THT, for example, the operator inputs various constants and variables into a calculation device that possesses equations (1) and (2), thereby determining the amount of THT to be filled M into the calculation device. od It would be good to have this calculated automatically. This would allow workers to determine the amount of THT to be filled at the site where refrigerant and odor components are being filled. od This can be adjusted appropriately. Alternatively, if the layout of the installation site for the air conditioning unit 1 is known, the refrigerant charge amount M can be adjusted. ref , refrigerant oil filling amount M oilThis allows us to obtain the rated cooling capacity (volume V of the living space LS), etc. Therefore, in a factory or the like where the air conditioning system 1 is installed, the amount of THT filling M can be determined based on the acquired layout and formulas (1) and (2). od The system may be configured to calculate the required amount and pre-fill it with THT (and refrigerant).

[0112] As described above, when filling the refrigerant circuit 10 with THT, by applying equation (1) or equation (2) and substituting the values ​​of each constant and variable, an appropriate filling amount M can be determined. od This makes it possible to determine the THT concentration so that even people sensitive to the smell of THT do not notice any abnormalities due to slight leakage, and also so that even people insensitive to the smell of THT can notice an abnormality in the flammable range. Moreover, equations (1) and (2) include terms that represent the effect of dissolution of refrigerant oil. For this reason, with the THT amount calculated by equations (1) and (2), the function of THT can be stably ensured in the filled state of the air conditioner 1.

[0113] Furthermore, the technology relating to this disclosure is not limited to the embodiments described above, and can be modified in various ways. For example, the refrigeration device 1 is not limited to the air conditioning device 1, but can be applied to various devices that are installed in a living space LS and have a refrigerant circuit 10 that circulates a refrigerant and THT. For example, other examples of the refrigeration device 1 include cooling devices for refrigerators and freezers, chiller units, heat pump type water heaters, etc.

[0114] Furthermore, the technology disclosed herein is not limited to configurations that satisfy both formulas (1) and (2) above, but may also satisfy only formula (1) or only formula (2). The amount of THT filling M that satisfies formula (1) od By obtaining this, a sufficient effect is achieved in preventing sensitive individuals from noticing any abnormalities when a slight refrigerant leak occurs. Conversely, the amount of THT filling M that satisfies equation (2) od By obtaining this, it is possible to achieve a sufficient effect in that even insensitive people can sense something is wrong when a refrigerant leak occurs, prompting them to take evacuation action.

[0115] <Regarding the nature and effects of this disclosure> The embodiments disclosed above have, for example, the following aspects and effects.

[0116] [Note 1] A refrigeration system (1) having a refrigerant circuit (10), wherein tetrahydrothiophene, an odor component, is sealed in the refrigerant circuit (10) together with the refrigerant and refrigerant oil, The amount of refrigerant leaking from the refrigerant circuit (10) in 4 minutes at a leak rate of 0.001 kg / h is M. leak1 [kg], the amount of the odor component to be filled into the refrigerant circuit (10) is M od [kg], the amount of refrigerant oil to be filled is M oil [kg], the solubility of the odor component in the refrigerant oil is S oil [ppm by weight], the amount of refrigerant to be filled into the refrigerant circuit (10) is M ref [kg], the volume of the living space (LS) is V[m 3 ], the density of the odor component is ρ[kg / m³] 3 When ] is set, the following equation (1) is satisfied, Refrigeration equipment.

[0117]

number

[0118] [Effects of Appendix 1] According to the above, the refrigeration system can fill the refrigerant circuit with an appropriate amount of odor component by satisfying equation (1). In other words, even if a small leak that does not reach the flammable range occurs in the refrigerant circuit, the refrigeration system will fill it with an amount of odor component that will not cause any abnormality in people sensitive to the smell of tetrahydrothiophene. As a result, the refrigeration system can be optimized for operation, such as reducing inquiries to service companies.

[0119] [Note 2] The amount of refrigerant leaking from the refrigerant circuit (10) in 4 minutes at a leak rate of 3 kg / h is M. leak2 [kg], the amount of the odor component to be filled into the refrigerant circuit (10) is Mod [kg], the amount of refrigerant oil to be filled is M oil [kg], the solubility of the odor component in the refrigerant oil is S oil [ppm by weight], the amount of refrigerant to be filled into the refrigerant circuit (10) is M ref [kg], the volume of the living space (LS) is V[m 3 ], the density of the odor component is ρ[kg / m³] 3 When ] is set, the following equation (2) is satisfied, The refrigeration equipment described in Appendix 1.

[0120]

number

[0121] [Effects of Appendix 2] By satisfying equation (2) in this way, the refrigeration system can be designed to contain an amount of odor component that will allow even a person insensitive to the smell of tetrahydrothiophene to detect an abnormality in the refrigerant circuit when a leak of flammable refrigerant occurs.

[0122] [Note 3] When the rated cooling capacity is 2.0kW or less, the volume of the living space (LS) is 56.5m³. 3 The following is: The refrigeration equipment described in Appendix 1 or 2.

[0123] [Effects of Appendix 3] This makes it possible to appropriately design the amount of odor components to be filled into refrigeration systems with a rated cooling capacity of 2.0 kW or less.

[0124] [Note 4] When the rated cooling capacity exceeds 2.0 kW and is 2.5 kW or less, the volume of the living space (LS) is 21.8 m³. 3 ~70.6m 3 The following is: The refrigeration equipment described in Appendix 1 or 2.

[0125] [Effects of Appendix 4] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 2.0 kW and 2.5 kW or less.

[0126] [Note 5] When the rated cooling capacity exceeds 2.5 kW and is 3.5 kW or less, the volume of the living space (LS) is 27.3 m³. 3 ~98.8m 3 That is, The refrigeration equipment described in Appendix 1 or 2.

[0127] [Effects of Appendix 5] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 2.5 kW and 3.5 kW or less.

[0128] [Note 6] When the rated cooling capacity exceeds 3.5 kW and is 5.0 kW or less, the volume of the living space (LS) is 38.2 m³. 3 ~141.2m 3 That is, The refrigeration equipment described in Appendix 1 or 2.

[0129] [Effects of Appendix 6] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 3.5 kW and 5.0 kW or less.

[0130] [Note 7] When the rated cooling capacity exceeds 5.0 kW, the volume V of the living space (LS) is 54.5 m³. 3 That's all. The refrigeration equipment described in Appendix 1 or 2.

[0131] [Effects of Appendix 7] This makes it possible to appropriately design the amount of odor components to be filled in refrigeration systems with a rated cooling capacity exceeding 5.0 kW.

[0132] [Note 8] The aforementioned refrigerant is a hydrocarbon-based refrigerant. A refrigeration device as described in any one of the items 1 to 7 of the appendix.

[0133] [Effects of Appendix 8] This allows the refrigeration system, in a configuration where hydrocarbon-based refrigerants are used to fill the refrigerant circuit, to optimize the amount of odor components being filled.

[0134] The refrigeration apparatus 1 according to the embodiments disclosed herein is illustrative in all respects and not restrictive. The embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be otherwise configured and combined in a non-consistent manner. [Explanation of Symbols]

[0135] 1. Refrigeration system (air conditioning system) 10 Refrigerant Circuit LS Living space

Claims

1. A refrigeration system (1) having a refrigerant circuit (10), wherein tetrahydrothiophene, which is an odor component, is sealed in the refrigerant circuit (10) together with the refrigerant and refrigerant oil, The amount of refrigerant leaking from the refrigerant circuit (10) in 4 minutes at a leak rate of 0.001 kg / h is M. ｌｅａｋ１ [kg], the amount of the odor component to be filled into the refrigerant circuit (10) M ｏｄ [kg], the amount of refrigerant oil to be filled is M ｏｉｌ [kg], the solubility of the odor component in the refrigerant oil is S ｏｉｌ [ppm by weight], M is the amount of refrigerant to be filled into the refrigerant circuit (10). ｒｅｆ [kg], the volume of the living space (LS) is V [m³] ３ ], the density of the odor component is ρ [kg / m³] ３ When ] is set, the following equation (1) is satisfied, Refrigeration equipment. [Math 1]

2. The leakage amount M [kg] of the refrigerant leaking from the refrigerant circuit (10) in 4 minutes at a leakage rate of 3 kg / h ｌｅａｋ２ The filling amount M ｏｄ [kg] of the odor component into the refrigerant circuit (10), the filling amount M ｏｉｌ [kg] of the refrigeration oil, the solubility S ｏｉｌ [weight ppm] of the odor component in the refrigeration oil, the filling amount M ｒｅｆ [kg] of the refrigerant into the refrigerant circuit (10), the volume V [m ｏｄ The filling amount M ｏｉｌ [kg] of the refrigeration oil ｏｉｌ The solubility S ｏｉｌ [weight ppm] of the odor component in the refrigeration oil ｏｉｌ The filling amount M ｒｅｆ [kg] of the refrigerant into the refrigerant circuit (10) ｒｅｆ When the volume of the living space (LS) is V [m ３ and the density of the odor component is ρ [kg / m ３ , the following formula (2) is satisfied The refrigeration apparatus according to claim 1. [Math 2]

3. When the rated cooling capacity is 2.0 kW or less, the volume of the living space (LS) is 56.5 m³. ３ The following is: The refrigeration apparatus according to claim 1 or 2.

4. When the rated cooling capacity exceeds 2.0 kW and is 2.5 kW or less, the volume of the living space (LS) is 21.8 m³. ３ ~70.6m ３ The following is: The refrigeration apparatus according to claim 1 or 2.

5. When the rated cooling capacity exceeds 2.5 kW and is 3.5 kW or less, the volume of the living space (LS) is 27.3 m³. ３ ~98.8m ３ That is, The refrigeration apparatus according to claim 1 or 2.

6. When the rated cooling capacity exceeds 3.5 kW and is 5.0 kW or less, the volume of the living space (LS) is 38.2 m³. ３ ~141.2m ３ That is, The refrigeration apparatus according to claim 1 or 2.

7. When the rated cooling capacity exceeds 5.0 kW, the volume V of the living space (LS) is 54.5 m³. ３ That's all. The refrigeration apparatus according to claim 1 or 2.

8. The aforementioned refrigerant is a hydrocarbon-based refrigerant. The refrigeration apparatus according to claim 1 or 2.

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