Method and apparatus for creating TS diagram of heating medium

Abstract

To create a TS diagram of a heat medium showing a pressure calorie effect by application and release of high pressure.SOLUTION: Deriving a 1TS line indicating a relationship between a temperature and an entropy in a low temperature phase of the heat transfer fluid based on a first specific heat and a first imaginary specific heat of the heat transfer fluid indicating a pressure-heat quantity effect; Deriving a second TS line in the high-temperature phase of the heat transfer medium based on the second specific heat and the second virtual specific heat of the heat transfer medium, and deriving the relationship between the temperature and the percentage of the high-temperature phase or the low-temperature phase in the heat transfer medium to which no pressure is applied and the heat transfer medium to which a predetermined pressure is applied based on the relationship between the temperature and the magnetic susceptibility in the heat transfer medium; A first inter-phase TS line when a heating medium to which no pressure is applied undergoes phase transition from a low-temperature phase to a high-temperature phase and a second inter-phase TS line when the heating medium to which a predetermined pressure is applied undergoes phase transition from the high-temperature phase to the low-temperature phase are added to the first and second TS lines.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to a method and apparatus for creating a TS diagram of a heat transfer medium that shows the pressure-calorie effect. [Background technology]

[0002] Rubidium-manganese-iron cyano complexes have been known as phase transition materials (see, for example, Non-Patent Documents 1, 2, and 3). Also known are heat storage and release systems that utilize the phase stability of rubidium-manganese-iron cyano complexes (see, for example, Patent Document 1), and heat absorption and release systems that utilize a heat medium containing a rubidium-manganese-iron cyano complex based on the pressure caloric effect (see, for example, Patent Document 2). The heat absorption and release system described in Patent Document 2 applies pressure to a heat medium to cause the rubidium-manganese-iron cyano complex to undergo a phase transition from a high-temperature phase to a low-temperature phase, thereby releasing heat from the heat medium. At the same time, the pressure applied to the heat medium is released to cause the rubidium-manganese-iron cyano complex to undergo a phase transition from a low-temperature phase to a high-temperature phase, thereby absorbing heat into the heat medium. By repeatedly applying and releasing pressure to the heat medium, the heat absorption and release system can function as a heat pump that transfers heat from a low-temperature region to a high-temperature region via the heat medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7218868 [Patent Document 2] International Publication No. 2023 / 002698 [Non-patent literature]

[0004] [Non-Patent Document 1] "A surprisingly large thermal hysteresis loop in a reversible phase transition of a rubidium manganese hexacyanoferrate" S. Ohkoshi, T. Matsuda, H. Tokoro, and K. Hashimoto, Chem. Mater., 17, 81-84 (2005). [Non-patent document 2] "A large thermal hysteresis loop produced by a charge-transfer phase transition in a rubidium manganese-hexacyanoferrate" H. Tokoro, S. Ohkoshi, T. Matsuda, and K. Hashimoto, Inorg. Chem., 43, 5231-5236 (2004). [Non-patent document 3] "Theoretical prediction of a charge-transfer phase transition" H. Tokoro, A. Namai, M. Yoshikiyo, K. Chiba, R. Fujiwara, and S. Ohkoshi, Scientific Reports, 8, 63 (2018). Summary of the Invention [Problem to be solved by the invention]

[0005] When constructing a heat absorption / dissipation system such as the one described above, a temperature-entropy diagram (hereinafter referred to as a "TS diagram") showing the correlation between the temperature and entropy of a heat medium is required to understand the amount of heat released and absorbed by the application and release of pressure to the heat medium that exhibits a pressure caloric effect. However, it is difficult to measure the entropy of a heat medium to which, for example, several hundred MPa of pressure is applied, and it has been virtually impossible to create a TS diagram for a heat medium containing, for example, a rubidium-manganese-iron cyano complex, which exhibits a huge pressure caloric effect by the application and release of high pressure.

[0006] Therefore, a main object of the present disclosure is to make it possible to create a TS diagram of a heat transfer medium that exhibits a pressure-calorie effect by applying and releasing high pressure. [Means for solving the problem]

[0007] A method for creating a TS diagram of a heat medium according to the present disclosure is a method for creating a TS diagram of a heat medium showing a pressure-calorie effect, the method comprising: measuring a first specific heat in a low-temperature phase of the heat medium and a second specific heat in a high-temperature phase of the heat medium for each temperature; deriving a first virtual specific heat of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low-temperature phase to the high-temperature phase and a second virtual specific heat of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high-temperature phase to the low-temperature phase; deriving a first TS line showing the relationship between temperature and entropy in the low-temperature phase of the heat medium based on the first specific heat and the first virtual specific heat; and deriving a TS line showing the relationship between temperature and entropy in the low-temperature phase of the heat medium based on the second specific heat and the second virtual specific heat. A second TS line showing the relationship between temperature and entropy in the high-temperature phase of the body is derived, and a first inter-phase TS line showing the relationship between temperature and entropy when the heat medium to which no pressure is applied transitions from the low-temperature phase to the high-temperature phase and a second inter-phase TS line showing the relationship between temperature and entropy when the heat medium to which the predetermined pressure is applied transitions from the high-temperature phase to the low-temperature phase are added to the first and second TS lines based on the relationship between temperature and the proportion of the high-temperature phase or the low-temperature phase in the heat medium to which no pressure is applied and in the heat medium to which a predetermined pressure is applied, which is obtained from the relationship between temperature and magnetic susceptibility in the heat medium.

[0008] For a heat medium that exhibits a pressure caloric effect, the first specific heat in the low-temperature phase and the second specific heat in the high-temperature phase of the heat medium can be measured at each temperature. The first virtual specific heat of the heat medium, assuming that the heat medium does not undergo a phase transition from the low-temperature phase to the high-temperature phase, and the second virtual specific heat of the heat medium, assuming that the heat medium does not undergo a phase transition from the high-temperature phase to the low-temperature phase, can be derived for each temperature. Furthermore, a first TS line, which shows the relationship between temperature and entropy in the low-temperature phase of the heat medium, can be derived based on the first specific heat and the first virtual specific heat. A second TS line, which shows the relationship between temperature and entropy in the high-temperature phase of the heat medium, can be derived based on the second specific heat and the second virtual specific heat. While it is difficult to measure the entropy of a heat medium subjected to a pressure of, for example, several hundred MPa, it is possible to measure the magnetic susceptibility of the heat medium while varying the temperature of the heat medium subjected to high pressure. Furthermore, the product of the magnetic susceptibility and temperature of a heat medium exhibiting a pressure-caloric effect changes depending on the phase transition between the low-temperature and high-temperature phases of the heat medium, which involves temperature hysteresis. Therefore, the relationship between the temperature and magnetic susceptibility of a heat medium without applied pressure can be used to determine the relationship between the temperature and the proportion of the high-temperature or low-temperature phase in the heat medium without applied pressure. The relationship between the temperature and magnetic susceptibility of the heat medium with applied pressure can be used to determine the relationship between the temperature and the proportion of the high-temperature or low-temperature phase in the heat medium with applied pressure. The method disclosed herein then assigns the proportion of the high-temperature or low-temperature phase in the heat medium without applied pressure and the heat medium with applied pressure to the first and second TS lines, respectively. This allows the addition of a first interphase TS line, which shows the relationship between temperature and entropy when a heat medium without applied pressure transitions from the low-temperature phase to the high-temperature phase, and a second interphase TS line, which shows the relationship between temperature and entropy when a heat medium with applied pressure transitions from the high-temperature phase to the low-temperature phase. As a result, it is possible to create a TS diagram that clearly shows the characteristics of a heat medium that exhibits a pressure calorie effect when high pressure is applied and released, making it possible to properly understand the amount of heat released and absorbed that is obtained when pressure is applied and released to a heat medium that exhibits a pressure calorie effect.

[0009] The TS diagram creation device for a heat medium according to the present disclosure includes an information acquisition unit that acquires a first specific heat for each temperature in a low-temperature phase of the heat medium, a second specific heat for each temperature in a high-temperature phase of the heat medium, a first virtual specific heat for each temperature of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low-temperature phase to the high-temperature phase, a second virtual specific heat for each temperature of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high-temperature phase to the low-temperature phase, and a relationship between the temperature and the proportion of the high-temperature phase or the low-temperature phase in the heat medium when no pressure is applied and in the heat medium when a predetermined pressure is applied, which is obtained from the relationship between the temperature and magnetic susceptibility in the heat medium; and a second TS line indicating the relationship between the temperature and entropy when the heat medium to which the pressure is not applied transitions from the low temperature phase to the high temperature phase, based on the relationship between the temperature and the proportion of the high temperature phase or the low temperature phase in the heat medium to which the pressure is not applied and in the heat medium to which a predetermined pressure is applied, based on the relationship between the temperature and the proportion of the high temperature phase or the low temperature phase in the heat medium to which the pressure is not applied and in the heat medium to which a predetermined pressure is applied, to the first and second TS lines.

[0010] With this device, it is possible to create a TS diagram that clearly shows the characteristics of a heat medium that exhibits a pressure calorie effect when high pressure is applied and released, making it possible to properly understand the amount of heat released and absorbed by a heat medium that exhibits a pressure calorie effect when pressure is applied and released. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a TS diagram creation device for a heat medium according to the present disclosure. [Figure 2] 1 is a diagram showing an example of a TS diagram created by the TS diagram creation device of the present disclosure. [Figure 3] 1 is a flowchart for explaining a TS diagram creation method according to the present disclosure. [Figure 4] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 5] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 6] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 7] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 8] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 9] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 10] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 11] 1 is a diagram for explaining a TS diagram creation method according to the present disclosure. [Figure 12] FIG. 1 is a schematic diagram illustrating an example of a pressurizing device for pressurizing a heat medium exhibiting a pressure calorie effect. [Figure 13] 1 is a table showing a TS diagram created by the TS diagram creation device of the present disclosure and actual measured values ​​of the amount of temperature change of a heat medium to which a predetermined pressure is applied and then released. [Figure 14] 1 is a diagram showing the amount of temperature change of a heat medium when a predetermined pressure is applied and released. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a block diagram showing a TS diagram creation device for a heat transfer medium (hereinafter simply referred to as "TS diagram creation device") according to the present disclosure. The TS diagram creation device 1 shown in the figure is capable of creating a TS diagram (temperature-entropy diagram) of a heat transfer medium containing a bistability phase transition material that exhibits a pressure-calorie effect. In this embodiment, the heat transfer medium is a rubidium-manganese-iron cyano complex (composition formula: Rb x Mn[Fe(CN)6] y , Mn doped with divalent metal ions, or Fe doped with trivalent metal ions, hereinafter referred to as "RbMnFe complexes."

[0014] The RbMnFe complex exhibits bistability in two states: a low-temperature phase in which the manganese and iron valences are Mn(III)-Fe(II), and a high-temperature phase in which the manganese and iron valences are Mn(II)-Fe(III). That is, the RbMnFe complex exhibits bistability at the first phase transition temperature T LH When heated above this temperature, the material undergoes a phase transition from the low-temperature phase to the high-temperature phase, absorbing heat. LH Second phase transition temperature T HL Below this temperature, the RbMnFe complex undergoes a phase transition from the high-temperature phase to the low-temperature phase, releasing heat. Furthermore, the phase transition of the RbMnFe complex is accompanied by thermal hysteresis, and after the RbMnFe complex undergoes a phase transition from the low-temperature phase to the high-temperature phase, it stores the heat absorbed during the phase transition to the high-temperature phase until it transitions back to the low-temperature phase.

[0015] Furthermore, the RbMnFe complex exhibits a large barocaloric effect upon application and release of high pressure. That is, when the RbMnFe complex is pressurized, the first phase transition temperature T LH and the second phase transition temperature T from the high-temperature phase to the low-temperature phase HL Basically, the higher the pressure applied to the RbMnFe complex, the higher the first and second phase transition temperatures T LH ,T HL Therefore, if a relatively high pressure is applied to the RbMnFe complex, the first phase transition temperature T LH The second phase transition temperature T from the high-temperature phase to the low-temperature phase is lower than HLSince the temperature of the RbMnFe complex is increased, it is possible to cause the RbMnFe complex to undergo a phase transition from the high-temperature phase to the low-temperature phase without significantly lowering the temperature of the RbMnFe complex.

[0016] Therefore, when pressure is applied to the RbMnFe complex in a room temperature environment, the RbMnFe complex releases heat to a target object in response to the phase transition from the high-temperature phase to the low-temperature phase, thereby heating the target object. Furthermore, when the pressure applied to the RbMnFe complex is released, the first phase transition temperature T LH and the second phase transition temperature T from the high-temperature phase to the low-temperature phase HL decreases (returns to original state). Therefore, by releasing the pressure applied to the RbMnFe complex (reducing the applied pressure to substantially zero), it is possible to cause the RbMnFe complex to undergo a phase transition from the low-temperature phase to the high-temperature phase without significantly increasing the temperature. As a result, by releasing the pressure applied to the RbMnFe complex, the RbMnFe complex can absorb heat from a predetermined object to be cooled in accordance with the phase transition from the low-temperature phase to the high-temperature phase, thereby cooling the object to be cooled.

[0017] In this embodiment, the TS diagram creation device 1 is a computer including a CPU, ROM, RAM, input / output devices, etc. (not shown), and on which multiple programs are installed. As shown in FIG. 1, the TS diagram creation device 1 includes, as functional blocks, an information acquisition unit 10, a first calculation unit 11, and a second calculation unit 12, which are constructed by the cooperation of hardware such as a CPU and multiple programs installed in a ROM, and is capable of creating a TS diagram as shown in FIG. 2. The TS diagram shown in FIG. 2 is created using a rubidium cyano-bridged manganese-iron-cobalt inorganic compound (composition formula: RbMn[[Fe(CN)6]) as the RbMnFe complex. 0.92 [Co(CN)6] 0.08 This shows the relationship between temperature T and entropy S in a heat transfer medium containing HCl (H₂O).

[0018] The information acquiring unit 10 of the TS diagram creation device 1 acquires information necessary for creating a TS diagram, which is acquired using a measuring device, an analysis tool, etc. (not shown). Based on the information provided from the information acquiring unit 10, the first calculation unit 11 derives first TS lines (first TS curves) S1n(T) and S1p(T) that indicate the relationship between the temperature T and entropy S of the heat medium in the low-temperature phase, and also derives second TS lines (second TS curves) S2n(T) and S2p(T) that indicate the relationship between the temperature T and entropy S of the heat medium in the high-temperature phase. Based on the information provided by the information acquisition unit 10, the second calculation unit 12 adds first interphase TS lines (first interphase TS curves) S3n(T) and S3p(T) which indicate the relationship between the temperature T and entropy S when the heat medium undergoes a phase transition from a low-temperature phase to a high-temperature phase, and second interphase TS lines (second interphase TS curves) S4n(T) and S4p(T) which indicate the relationship between the temperature T and entropy S when the heat medium undergoes a phase transition from a high-temperature phase to a low-temperature phase, to the first and second TS lines S1n(T), S1p(T), S2n(T), and S2p(T).

[0019] Next, the procedure for creating a TS diagram by the TS diagram creation device 1, that is, the TS diagram creation method of the present disclosure, will be described with reference to FIGS.

[0020] As shown in FIG. 3, when creating a TS diagram, the information acquisition unit 10 of the TS diagram creation device 1 acquires information necessary for creating a TS diagram, namely, the first specific heat C1, the second specific heat C2, the first virtual specific heat Cv1, and the second virtual specific heat Cv2 of the target heat medium, as well as the temperature T and the proportion γ of the high-temperature phase in the heat medium. HT and the relationship therebetween are acquired (step S100).

[0021] The first specific heat C1 is the specific heat of the heat medium in the low-temperature phase without pressure, and was measured separately for each temperature T of the low-temperature phase, as shown in FIG. 4 . The second specific heat C2 is the specific heat of the heat medium in the high-temperature phase without pressure, and was measured separately for each temperature T of the high-temperature phase, as shown in FIG. 4 . In this embodiment, the first and second specific heats C1 and C2 were measured using a physical property measurement system PPMS (trademark) manufactured by Japan Quantum Design Co., Ltd. This measurement system can measure the first and second specific heats C1 and C2 for each temperature T while changing the temperature T of a test specimen obtained by compressing and solidifying an insoluble powder RbMnFe complex. As can be seen from FIG. 4 , when the heat medium undergoes a phase transition from the low-temperature phase to the high-temperature phase, the specific heat of the heat medium increases significantly from the first specific heat C1 to the second specific heat C2.

[0022] The first virtual specific heat Cv1 is a virtual specific heat of a heat medium when it is assumed that the heat medium does not undergo a phase transition from a low-temperature phase to a high-temperature phase and continues to be in the low-temperature phase. As shown in FIG. 5, the first virtual specific heat Cv1 is derived (calculated) separately by first-principles calculation for each temperature T of the virtual low-temperature phase (the temperature range in which the high-temperature phase would normally occur; see the two-dot chain line in the figure). The second virtual specific heat Cv2 is a virtual specific heat of a heat medium when it is assumed that the heat medium does not undergo a phase transition from a high-temperature phase to a low-temperature phase and continues to be in the high-temperature phase. ... derived (calculated) separately by first-principles calculation for each temperature T of the virtual high-temperature phase (the temperature range in which the low-temperature phase would normally occur; see the two-dot chain line in the figure). In this embodiment, the first and second virtual specific heats Cv1 and Cv2 were calculated using the first-principles electronic structure calculation program MedeA-VASP by Molsys Corporation.

[0023] Temperature T and the proportion of high-temperature phase γ HT The relationship between the temperature T and the magnetic susceptibility (molar magnetic susceptibility) X in the heat medium is M Based on the relationship between the magnetic susceptibility X of a heat medium that exhibits the pressure-calorie effect and the magnetic susceptibility X of a heat medium that exhibits the pressure-calorie effect, the magnetic susceptibility X of a heat medium that exhibits the pressure-calorie effect is calculated for both the heat medium that is not subjected to pressure and the heat medium that is subjected to a predetermined pressure Pref. M , more specifically, the magnetic susceptibility X M and temperature TM T varies depending on the phase transition between the low-temperature and high-temperature phases of the heat transfer medium with temperature hysteresis. Also, the magnetic susceptibility Χ of the heat transfer medium without pressure and with pressure Pref is M can be measured by a superconducting quantum interference device (SQUID) while increasing or decreasing the temperature T of the heat transfer medium.

[0024] And the magnetic susceptibility X measured by a superconducting quantum interference detector M Based on the above, the temperature T and the product value X in the heat medium to which no pressure is applied or the heat medium to which pressure Pref is applied as shown in FIG. 6 M Therefore, the relationship between the temperature T and the magnetic susceptibility X in a heat medium without pressure can be obtained. M (product value Χ M Based on the relationship between the temperature T and the proportion of high-temperature phase γ in a heat transfer medium without pressure, as shown in Figure 7, HT Similarly, the relationship between the temperature T and the magnetic susceptibility X in the heat medium to which pressure Pref is applied can be obtained. M (product value Χ M Based on the relationship between the temperature T and the proportion of high-temperature phase γ in the heat transfer medium to which pressure Pref is applied, as shown in Figure 8, HT You can get a relationship with.

[0025] In step S100, the information acquiring unit 10 transmits the acquired first and second specific heats C1 and C2 and the first and second virtual specific heats Cv1 and Cv2 to the first calculation unit 11. Also, in step S100, the information acquiring unit 10 transmits the acquired temperature T and the high-temperature phase ratio γ HT and the relationship between the temperature T and the proportion of high-temperature phase γ in the heat transfer medium to which pressure Pref is applied. HT The relationship between the above is transmitted to the second calculation unit 12.

[0026] The first calculation unit 11 integrates and plots the first specific heat C1 and the first virtual specific heat Cv1 within a predetermined temperature range, respectively, to derive a first TS line S1n(T) showing the relationship between the temperature T and the entropy S in the low-temperature phase of the heat medium to which no pressure is applied, as shown in Fig. 9 (step S110). Also, in step S110, the first calculation unit 11 integrates and plots the second specific heat C2 and the second virtual specific heat Cv2 within a predetermined temperature range, respectively, to derive a second TS line S2n(T) showing the relationship between the temperature T and the entropy S in the high-temperature phase of the heat medium to which no pressure is applied, as shown in Fig. 9.

[0027] Furthermore, the first calculation unit 11 derives a first TS line S1p(T) of the low temperature phase of the heat medium to which pressure Pref is applied, as shown in Fig. 10, based on the first TS line S1n(T) of the low temperature phase of the heat medium to which pressure is not applied derived in step S110 and the Maxwell relation (ΔS=-(ΔV / ΔT)ΔP) (step S120). Also, in step S120, the first calculation unit 11 derives a second TS line S2p(T) of the high temperature phase of the heat medium to which pressure Pref is applied, as shown in Fig. 10, based on the second TS line S2n(T) of the high temperature phase of the heat medium to which pressure is not applied derived in step S110 and the Maxwell relation (ΔS=-(ΔV / ΔT)ΔP). In addition, in a heat medium containing an RbMnFe complex, the difference (ΔS) between the first TS line S1n(T) of the low temperature phase of the heat medium to which no pressure is applied and the first TS line S1p(T) of the low temperature phase of the heat medium to which pressure Pref is applied, and the difference (ΔS) between the second TS line S2n(T) of the high temperature phase of the heat medium to which no pressure is applied and the second TS line S2p(T) of the high temperature phase of the heat medium to which pressure Pref is applied, are, for example, about 0.002-0.004 (J / K / kg), which are very small compared to the values ​​of the difference (ΔS) in polymers and plastic crystals.

[0028] When the first calculation unit 11 calculates the first TS lines S1n(T), S1p(T) and the second TS lines S2n(T), S2p(T), the second calculation unit 12 calculates the temperature T and the high-temperature phase ratio γ in the heat medium to which no pressure is applied from the information acquisition unit 10.HT 11, a first inter-phase TS line S3n(T) showing the relationship between the temperature T and entropy S when the heat medium to which no pressure is applied undergoes a phase transition from the low-temperature phase to the high-temperature phase, and a second inter-phase TS line S4n(T) showing the relationship between the temperature T and entropy S when the heat medium undergoes a phase transition from the high-temperature phase to the low-temperature phase, are added to the first and second TS lines S1n(T) and S2n(T) (step S130). Furthermore, in step S130, the second calculation unit 12 calculates the temperature T and the high-temperature phase ratio γ in the heat medium to which the pressure Pref from the information acquisition unit 10 is applied. HT Based on this relationship, as shown in FIG. 11, a first interphase TS line S3p(T) showing the relationship between the temperature T and entropy S when the heat medium to which pressure Pref is applied undergoes a phase transition from a low-temperature phase to a high-temperature phase, and a second interphase TS line S4p(T) showing the relationship between the temperature T and entropy S when the heat medium undergoes a phase transition from a high-temperature phase to a low-temperature phase, are added to the first and second TS lines S1p(T) and S2p(T), and the routine of FIG. 3 is terminated.

[0029] In this embodiment, the second calculation unit 12 calculates the ratio γ of the high temperature phase in the heat medium to which no pressure is applied, based on the first TS line S1n(T) and the second TS line S2n(T) of the heat medium to which no pressure is applied, in accordance with the following formula (1): HT is assigned to each temperature T, and the ratio γ of the high temperature phase in the heat medium to which the pressure Pref is applied is assigned to the first TS line S1p(T) and the second TS line S2p(T) of the heat medium to which the pressure Pref is applied. HT is assigned to each temperature T. In equation (1), "S(t)" is the entropy at temperature t, "S1(t)" is the entropy of the low-temperature phase at temperature t, "S2(t)" is the entropy of the high-temperature phase at temperature t, and "γ HT (t)” is the ratio of the high-temperature phase at temperature t (0≦γ HT(t)≦1). This makes it possible to obtain the TS diagram shown in Figure 2 by appropriately adding the first and second interphase TS lines S3n(T), S3p(T), S4n(T), and S4p(T) to the first and second TS lines S1n(T), S1p(T), S2n(T), and S2p(T). The TS diagram in Figure 2 shows the relationship between temperature T and entropy S when a pressure of Pref = 440 MPa is applied and released to a heat transfer medium containing the rubidium cyano-bridged manganese-iron-cobalt inorganic compound.

[0030] S(t)=γ HT (t) × S2(t) + (1-γ HT (t)) × S1(t)…(1)

[0031] The TS diagram shown in Figure 2 allows for accurate understanding of the amount of heat released and absorbed by a heat transfer medium exhibiting a pressure calorie effect when pressure is applied and released. Specifically, when the heat transfer medium is in a room-temperature environment (e.g., T = 20°C), the heat transfer medium illustrated in Figure 2 is in a high-temperature phase (on the second TS line S2n(T)). When a pressure of Pref = 440 MPa is applied, the heat transfer medium undergoes an isentropic change, releasing heat to the outside and undergoing a phase transition from the high-temperature phase to the low-temperature phase along the second interphase TS line S4p(T). Therefore, the horizontal distance (distance along the horizontal axis) from a point on the second TS line S2n(T) corresponding to a given temperature to the second interphase TS line S4p(T) indicates the maximum temperature rise of the heat transfer medium in response to the application of pressure Pref.

[0032] Furthermore, a heat medium to which a pressure of Pref = 440 MPa is applied in a room temperature environment is in a low-temperature phase (on the first TS line S1p(T)), and when the pressure Pref is released (application is stopped), the heat medium undergoes an isentropic change, absorbing heat from the outside, and can be considered to undergo a phase transition from the low-temperature phase to the high-temperature phase through the first interphase TS line S3n(T). Therefore, the horizontal distance (distance in the horizontal axis direction) from a point on the first TS line S1p(T) corresponding to an arbitrary temperature to the first interphase TS line S3n(T) indicates the maximum amount of temperature drop (absolute value) of the heat medium in response to the release of the pressure Pref.

[0033] To verify the usefulness of the TS diagram created by the TS diagram creation device 1, as shown in FIG. 2, the inventors measured the temperature of a heat transfer medium using a thermocouple while applying and releasing pressure to the heat transfer medium using a pressure device 20 shown in FIG. 12. The pressure device 20 is a non-adiabatic pressure system including an upper punch 21 as a pressure member, a lower punch (load cell) 22 as a support member, and a die set 23. The heat transfer medium used in the verification was a solid heat transfer medium 50 obtained by compressing and solidifying the rubidium cyano-bridged manganese-iron-cobalt inorganic compound, which is an insoluble powder. The solid heat transfer medium 50 was placed in the cylindrical portion of the die set 23 so as to be located between the pressure portion of the upper punch 21 and the support portion of the lower punch 22. Seat plates 24 were placed between the pressure portion of the upper punch 21 and the solid heat transfer medium 50, and between the support portion of the lower punch 22 and the solid heat transfer medium 50.

[0034] 13 shows the temperature change (temperature increase and decrease) ΔT of the solid heat transfer medium 50 measured while applying and releasing a pressure of Pref = 440 MPa to the solid heat transfer medium 50 using the pressure device 20 at a plurality of temperatures (ambient temperatures) T, plotted on the TS diagram of FIG. 2. As shown in the figure, the temperature increase (measured value) of the heat transfer medium in response to the application (pressurization) of the pressure Pref at each temperature T did not exceed the temperature on the second interphase TS line S4p(T) corresponding to that temperature T. Furthermore, the temperature decrease (measured value) of the heat transfer medium in response to the release of the pressure Pref at each temperature T did not exceed the temperature on the first interphase TS line S3n(T) corresponding to that temperature T.

[0035] 14, the temperature of solid heat transfer medium 50 rises sharply in response to the application of pressure Pref, then quickly returns to its original state, and drops sharply in response to the release of pressure Pref, then quickly returns to its original state. Therefore, if pressurizing device 20 is sufficiently insulated, it is expected that the measured value will be closer to the temperature on second interphase TS line S4p(T) or first interphase TS line S3n(T). Furthermore, if it is assumed that heating (space heating) of an object using the solid heat medium 50 becomes possible when the amount of temperature rise in response to the application of pressure Pref exceeds 30°C, and that cooling (air conditioning) of an object becomes possible using the solid heat medium 50 when the absolute value of the amount of temperature drop in response to the release of pressure exceeds 30°C, then from the results shown in Figure 13, when Pref = 440 MPa, in the range of -15°C < T < 9°C, only heating (space heating) of an object can be performed, in the range of 9°C < T < 35°C, both heating (space heating) of an object and cooling (air conditioning) of an object can be performed, and in the range of 35°C < T < 60°C, only cooling (air conditioning) of an object can be performed.

[0036] 13, in order to grasp the heat absorption and radiation performance of a heat medium exhibiting a pressure calorie effect, that is, the amount of heat radiation and absorption obtained by applying and releasing pressure to the heat medium, it is sufficient to add at least the first interphase TS line S3n(T) and the second interphase TS line S4p(T) to the first TS lines S1n(T), S1p(T) and the second TS lines S2n(T), S2p(T) in step S130 of FIG. 3. Therefore, in step S100 of FIG. 3, the information acquisition unit 10 calculates the temperature and the proportion γ of the high-temperature phase in the heat medium to obtain the first interphase TS line S3p(T). HT and the temperature and the proportion of high-temperature phases in the heat transfer medium to obtain the second interphase TS line S4n(T) HT It is not necessary to obtain a relationship with

[0037] In step S100 of FIG. 3, the information acquiring unit 10 acquires the temperature T and the magnetic susceptibility X of the heat medium. M The temperature T and the proportion of low-temperature phase γ in a heat medium with no pressure applied and a heat medium with a specified pressure Pref applied are obtained from the relationship LTIn this case, in step S130, the ratio γ of the low-temperature phase in the heat medium to which pressure is not applied is calculated for the first TS lines S1n(T), S1p(T) and the second TS lines S2n(T), S2p(T). LT and the fraction of the low-temperature phase in the heat transfer medium to which pressure Pref is applied γ LT is preferably assigned to each temperature T. Furthermore, by applying the above-described method for creating a TS diagram, it is also possible to create a TS diagram that shows the relationship between the temperature T and the entropy S of a heat medium that has been pressurized from a first pressure to a second pressure higher than the first pressure and then decompressed to the first pressure.

[0038] As described above, the TS diagram creation device 1 for a heat medium includes an information acquisition unit 10, a first calculation unit 11, and a second calculation unit 12. The information acquisition unit 10 acquires a first specific heat C1 for each temperature T in the low-temperature phase of the heat medium, a second specific heat C2 for each temperature T in the high-temperature phase of the heat medium, a first virtual specific heat Cv1 for each temperature T of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low-temperature phase to the high-temperature phase, a second virtual specific heat Cv2 for each temperature T of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high-temperature phase to the low-temperature phase, and a magnetic susceptibility X for the temperature T of the heat medium. M The temperature T and the ratio γ of the high temperature phase (or low temperature phase) in the heat medium to which no pressure is applied and the heat medium to which a predetermined pressure Pref is applied are obtained from the relationship HT (or γ LT ) and the relationship therebetween (step S100).

[0039] The first calculation unit 11 also derives first TS lines S1n(T), S1p(T) showing the relationship between the temperature T and entropy S in the low-temperature phase of the heat medium based on the first specific heat C1 and the first virtual specific heat Cv1, and derives second TS lines S2n(T), S2p(T) showing the relationship between the temperature T and entropy S in the high-temperature phase of the heat medium based on the second specific heat C2 and the second virtual specific heat Cv2 (steps S110, S120). Furthermore, the second calculation unit 12 calculates the ratio γ of the temperature T to the high-temperature phase (or low-temperature phase) in the heat medium to which pressure Pref is not applied and the heat medium to which pressure Pref is applied. HT (or γLT ), a first interphase TS line S3n(T) showing the relationship between the temperature T and entropy S when a heat medium to which no pressure is applied undergoes a phase transition from a low-temperature phase to a high-temperature phase, and a second interphase TS line S4p(T) showing the relationship between the temperature T and entropy S when a heat medium to which a predetermined pressure Pref is applied undergoes a phase transition from a high-temperature phase to a low-temperature phase, are added to the first and second TS lines S1n(T), S1p(T), S2n(T), and S2p(T) (step S130).

[0040] That is, for a heat medium that exhibits a pressure-calorie effect, a first specific heat C1 in the low-temperature phase and a second specific heat C2 in the high-temperature phase of the heat medium are measured for each temperature T, and a first virtual specific heat Cv1 of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low-temperature phase to the high-temperature phase and a second virtual specific heat Cv2 of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high-temperature phase to the low-temperature phase can be derived for each temperature T. Furthermore, first TS lines S1n(T) and S1p(T) showing the relationship between the temperature T and entropy S of the heat medium in the low-temperature phase can be derived based on the first specific heat C1 and the first virtual specific heat Cv1, and second TS lines S2n(T) and S2p(T) showing the relationship between the temperature T and entropy S of the heat medium in the high-temperature phase can be derived based on the second specific heat C2 and the second virtual specific heat Cv2.

[0041] In addition, it is difficult to measure the entropy S of a heat medium to which a pressure of several hundred MPa is applied, but it is possible to measure the magnetic susceptibility (molar magnetic susceptibility) X of the heat medium by changing the temperature T of the heat medium to which high pressure is applied. M Furthermore, it is possible to measure the magnetic susceptibility X of a heat medium that exhibits a pressure caloric effect. M and temperature T M T varies depending on the phase transition between the low-temperature and high-temperature phases of the heat transfer medium, which involves temperature hysteresis. Therefore, the temperature T and magnetic susceptibility X in a heat transfer medium without pressure are M From the relationship between the temperature T and the ratio of the high temperature phase (or low temperature phase) in the heat medium to which the pressure is not applied, γ HT (or γ LT) can be obtained, and the relationship between the temperature and magnetic susceptibility X in the heat medium to which pressure Pref is applied can be obtained. M From the relationship between the temperature T and the ratio of the high temperature phase (or low temperature phase) in the heat medium to which the pressure Pref is applied, γ HT (or γ LT ) can be obtained.

[0042] Then, in step S130, the ratio γ of the high temperature phase (or low temperature phase) in the heat medium to which no pressure is applied and the heat medium to which the pressure Pref is applied is calculated for the first and second TS lines S1n(T), S1p(T), S2n(T), and S2p(T). HT (or γ LT ) is assigned to each temperature. This makes it possible to add, to the first and second TS lines S1n(T), S1p(T), S2n(T), and S2p(T), a first interphase TS line S3n(T), which shows the relationship between the temperature T and entropy S when a heat medium with no pressure applied undergoes a phase transition from a low-temperature phase to a high-temperature phase, and a second interphase TS line S4p(T), which shows the relationship between the temperature T and entropy S when a heat medium with pressure Pref applied undergoes a phase transition from a high-temperature phase to a low-temperature phase. As a result, a TS diagram can be created that clearly shows the characteristics of a heat medium that exhibits a pressure caloric effect when high pressure is applied and released, making it possible to accurately understand the amount of heat released and absorbed by a heat medium that exhibits a pressure caloric effect when pressure is applied and released.

[0043] In the above embodiment, in addition to the first and second TS lines S1n(T) and S2n(T) of a heat medium to which no pressure is applied, which are obtained based on the first specific heat C1 and the first virtual specific heat Cv1 or the second specific heat C2 and the second virtual specific heat Cv2, the first and second TS lines S1p(T) and S2p(T) of a heat medium to which a predetermined pressure Pref is applied are derived based on the first and second TS lines S1n(T) and S2n(T) and Maxwell's equations. This makes it possible to create a TS diagram that clearly shows the characteristics of a heat medium that exhibits a pressure-calorie effect when high pressure is applied and released. However, for materials with very low thermal expansion, such as RbMnFe complexes, the difference between the TS line of a heat medium to which no pressure is applied and the TS line of a heat medium to which a predetermined pressure is applied is very small. Therefore, the TS diagram may be created using only either the first and second TS lines S1n(T), S2n(T) of the heat medium to which no pressure is applied, or the first and second TS lines S1p(T), S2p(T) of the heat medium to which pressure Pref is applied.

[0044] Furthermore, the present disclosure is extremely useful for constructing a heat absorption / dissipation system using a heat transfer medium containing a RbMnFe complex, which exhibits a large barocaloric effect upon application and release of high pressure, as described above. However, it goes without saying that the present disclosure can also create a TS diagram for a heat transfer medium containing a phase transition material other than a RbMnFe complex.

[0045] It should be noted that the invention of the present disclosure is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely one specific form of the invention described in the Summary of the Invention section, and does not limit the elements of the invention described in the Summary of the Invention section. [Industrial Applicability]

[0046] The presently disclosed invention can be used in various industries that use heat transfer media that exhibit a pressure calorie effect. [Explanation of symbols]

[0047] 1 TS line diagram fabrication device, 10 Information acquisition unit, 11 First calculation unit, 12 Second calculation unit, 20 Pressure device, 50 Solid heat medium, C1 First specific heat, C2 Second specific heat, Cv1 First provisional specific heat, Cv2 Second provisional specific heat, S1n(T),S1p(T) First TS line, S2n(T),S2p(T) Second TS line, S3n(T),S3p(T) First phase alternating TS line, S4n(T),S4p(T) Second phase alternating TS line.

Claims

1. A method for creating a TS diagram of a heat transfer medium showing a pressure-calorie effect, comprising: measuring a first specific heat of the heat medium in a low temperature phase and a second specific heat of the heat medium in a high temperature phase for each temperature; Deriving, for each temperature, a first virtual specific heat of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low temperature phase to the high temperature phase, and a second virtual specific heat of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high temperature phase to the low temperature phase; deriving a first TS line showing the relationship between temperature and entropy in the low-temperature phase of the heat medium based on the first specific heat and the first virtual specific heat, and deriving a second TS line showing the relationship between temperature and entropy in the high-temperature phase of the heat medium based on the second specific heat and the second virtual specific heat; a first interphase TS line showing the relationship between temperature and entropy when the heat medium to which no pressure is applied transitions from the low-temperature phase to the high-temperature phase, and a second interphase TS line showing the relationship between temperature and entropy when the heat medium to which the predetermined pressure is applied transitions from the high-temperature phase to the low-temperature phase, based on the relationship between temperature and magnetic susceptibility in the heat medium and the proportion of the high-temperature phase or the low-temperature phase in the heat medium to which no pressure is applied and the heat medium to which a predetermined pressure is applied, which is obtained from the relationship between temperature and magnetic susceptibility in the heat medium; How to create a TS diagram for a heat transfer medium.

2. 2. The method for creating a TS diagram of a heat transfer medium according to claim 1, a TS line of the heat medium to which the pressure is not applied, which is obtained based on the first specific heat and the first virtual specific heat, or the second specific heat and the second virtual specific heat, and a TS line of the heat medium to which the predetermined pressure is applied, which is obtained based on the TS line of the heat medium to which the pressure is not applied and Maxwell's relation.

3. 3. The method for creating a TS diagram for a heat transfer medium according to claim 1, wherein the heat transfer medium contains a rubidium-manganese-iron cyano complex.

4. A TS diagram creation device for a heat transfer medium showing a pressure-calorie effect, an information acquisition unit that acquires a first specific heat for each temperature in a low temperature phase of the heat medium, a second specific heat for each temperature in a high temperature phase of the heat medium, a first virtual specific heat for each temperature of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the low temperature phase to the high temperature phase, a second virtual specific heat for each temperature of the heat medium when it is assumed that the heat medium does not undergo a phase transition from the high temperature phase to the low temperature phase, and a relationship between the temperature and the proportion of the high temperature phase or the low temperature phase in the heat medium to which no pressure is applied and in the heat medium to which a predetermined pressure is applied, which is obtained from a relationship between the temperature and magnetic susceptibility in the heat medium; a first calculation unit that derives a first TS line that indicates the relationship between temperature and entropy in the low-temperature phase of the heat medium based on the first specific heat and the first virtual specific heat, and that derives a second TS line that indicates the relationship between temperature and entropy in the high-temperature phase of the heat medium based on the second specific heat and the second virtual specific heat; a second calculation unit that adds, to the first and second TS lines, a first inter-phase TS line that indicates the relationship between temperature and entropy when the heat medium to which the pressure is not applied undergoes a phase transition from the low temperature phase to the high temperature phase, and a second inter-phase TS line that indicates the relationship between temperature and entropy when the heat medium to which the predetermined pressure is applied undergoes a phase transition from the high temperature phase to the low temperature phase, based on the relationship between temperatures and proportions of the high temperature phase or the low temperature phase in the heat medium to which the pressure is not applied and the heat medium to which the predetermined pressure is applied; A TS diagram creation device for a heat medium comprising:

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