JP2006029614A - Vapor compression type heat pump system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor compression type heat pump system using an internal combustion engine as a drive source capable of flexibly corresponding to load fluctuation. <P>SOLUTION: The vapor compression type heat pump system is provided with a refrigerating cycle arranged with a compressor 10 using the engine as the drive source, a condenser 20, an expansion valve 30, and an evaporator 40 in this order. It is a cooling system comprised by connecting a first reservoir 60 storing a liquid refrigerant to a refrigerant pipe connecting the condenser 20 and the expansion valve 30, and connecting a second reservoir 70 storing a gas refrigerant to a refrigerant pipe connecting the evaporator 40 and the compressor 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vapor compression heat pump system. More specifically, the present invention relates to a vapor compression heat pump system in which the drive source of the compressor is an internal combustion engine (engine). The system of the present invention is applied to a cooling or heating system such as cooling or heating.

  A vapor compression heat pump system is known as a system used for air conditioning air conditioning, refrigeration, refrigeration, and the like. A vapor compression heat pump system is a system in which refrigerant circulates through a compressor, a condenser, an expansion valve, and an evaporator. The gaseous refrigerant compressed by the compressor is condensed into a liquid in the condenser. The liquid refrigerant is conveyed to the evaporator through the expansion valve and is evaporated in the evaporator. At the time of evaporation, the surrounding heat is taken as evaporation heat, and as a result, the surrounding environment is cooled. The evaporated gaseous refrigerant is conveyed to the compressor and compressed again. It is known that a vapor compression heat pump system can be used for cooling and conversely for heating.

  In a vapor compression heat pump system, an electric motor is widely used as a compressor drive source. For example, Non-Patent Document 1 introduces an air conditioning system that uses carbon dioxide as a refrigerant. However, in order to reduce the social burden related to power generation facilities, it is required to reduce power consumption during the daytime in summer when power demand peaks.

  As for the vapor compression heat pump system, it is only necessary to install a compressor driven by an engine such as a gas engine or a diesel engine instead of a compressor driven by a motor. is there. For this reason, development of a vapor compression heat pump system using an engine is progressing and gradually penetrating into society. For example, a vehicle air conditioner that uses an engine as a power source of a compressor is disclosed as a cooling system using the engine (see Patent Document 1).

However, the engine is difficult to cope with load fluctuations, and there is a problem that energy efficiency decreases when the required power of the compressor fluctuates. In the case where electricity is used as a drive source, a technique for improving energy efficiency by inverter control has been developed. However, in the case where an engine is used as a drive source, it is difficult to efficiently cope with load fluctuations. Although it is possible to control the engine speed, the energy efficiency is greatly reduced, especially at low speeds. This can also be understood from the fact that in a hybrid vehicle combining an engine and an electric motor, the fuel consumption is greatly improved by controlling the engine at an optimum rotational speed.
Takumi Hashizume "Air conditioning system using CO2 refrigerant" Construction equipment and piping work 2001.3, p6-11 JP 2001-121946 A (FIG. 5, paragraph 0050)

  An object of the present invention is to provide a vapor compression heat pump system using an engine as a drive source, which can flexibly cope with fluctuations in load.

  The present invention is a vapor compression heat pump system including a refrigerant cycle in which an engine-driven compressor, a condenser, an expansion valve, and an evaporator are arranged in this order, and the condenser and the expansion valve A first reservoir that stores liquid refrigerant or gas refrigerant is connected to the refrigerant pipe that connects, and a second reservoir that stores gas refrigerant is connected to the refrigerant pipe that connects the evaporator and the compressor. It is a vapor compression heat pump system.

  The vapor compression heat pump system using the engine of the present invention as a drive source can flexibly cope with output fluctuations. The vapor compression heat pump system of the present invention reduces the financial burden on the user regarding power consumption. Moreover, the spread of the vapor compression heat pump system of the present invention to society reduces the social burden on the amount of power supply during the summer day.

  Hereinafter, the present invention will be described in detail. The following description mainly describes an embodiment in which the vapor compression heat pump system of the present invention is used as a cooling system, but the technical scope of the present invention is not limited to such an embodiment. The vapor compression heat pump system of the present invention can be used for both air conditioning and heating, and can also be used as a heating system and / or a cooling system other than air conditioning. For example, when the present invention is used as a heating system, the object may be heated using heat generated in the condenser.

  Moreover, in this application, although the medium used is described as a "refrigerant", when this invention is used as a heating or a heater, it functions as a heat medium which conveys heat to object. However, since the heating in the condenser and the cooling in the evaporator are integrated with each other, they are described as “refrigerant” in the present application.

  First, the concept of the cooling system of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of the cooling system of the present invention. In FIG. 1, the horizontal axis indicates the enthalpy of the refrigerant, and the right side indicates that the enthalpy of the refrigerant is higher. The vertical axis indicates the pressure, and the higher the pressure, the higher the pressure of the refrigerant.

  In the cooling system, a compressor 10, a condenser 20, an expansion valve 30, and an evaporator 40, which are driven by an engine, are arranged in this order, and these are connected by a refrigerant pipe 50 through which a refrigerant is conveyed.

  The refrigerant in the gas state is compressed in the compressor 10, and both the enthalpy and the pressure become high (state A). The high-pressure and high-temperature refrigerant is condensed and liquefied in the condenser 20 (state B). At this time, heat radiation from the refrigerant to the outside occurs with the condensation of the refrigerant. When the cooling system is an air conditioning system, the condenser 20 is disposed outside the room, and the gas refrigerant is cooled using air, water, or the like. The liquefied refrigerant expands in the expansion valve 30 and is easily vaporized in the evaporator 40 (state C). The expansion valve 30 usually generates low-pressure and low-temperature liquid refrigerant by leaking the liquid refrigerant through a small hole. The low-pressure and low-temperature liquid refrigerant is vaporized in the evaporator 40, and becomes a gaseous refrigerant (state D). At this time, heat absorption from the outside to the refrigerant occurs as the refrigerant evaporates. When the cooling system is an air conditioning system, the atmosphere is cooled by this heat absorption.

  In the present invention, the drive source of the compressor 10 is an engine. However, the energy efficiency of the engine is good when the engine is stably operated in a predetermined state, but greatly decreases when the output is varied. In particular, at low speed, the energy efficiency is greatly reduced.

  This problem can be solved by arranging the first reservoir 60 and the second reservoir 70. The first reservoir 60 is connected to a refrigerant pipe 50 that connects the condenser 20 and the expansion valve 30. As a connection form, for example, a valve is arranged in the refrigerant pipe 50 that connects the condenser 20 and the expansion valve 30, and liquid refrigerant is taken in and out from the first reservoir 60 as necessary. The second reservoir 70 is connected to a refrigerant pipe that connects the evaporator 40 and the compressor 10. As a connection form, for example, a valve is arranged in the refrigerant pipe 50 connecting the evaporator 40 and the compressor 10, and gas refrigerant is taken in and out from the second reservoir 70 as necessary.

  In a general cooling cycle, the refrigerant is liquefied in the state B, and the first reservoir 60 is a reservoir that stores the refrigerant in the liquid state. However, depending on the type of refrigerant and the compression pressure, there may be a case where the state B does not completely liquefy. In this case, a high-pressure gas reservoir may be used as the first reservoir 60.

  If the 1st store 60 and the 2nd store 70 are arranged like the present invention, it is possible to carry out stable operation of the engine which is a drive source of compressor 10 in an efficient state. This effect will be described with reference to the drawings. FIG. 2 is a graph showing the relationship between time and capacity required for the cooling system. FIG. 3 is a graph showing the relationship between time and the load on the compressor in a cooling system that does not have a first reservoir and a second reservoir. FIG. 4 is a graph showing the relationship between time and the load on the compressor in a cooling system having a first reservoir and a second reservoir.

  As you can easily imagine when considering an air conditioner, the capacity required for a cooling system is not constant throughout the day. In the case of an air conditioner, the load increases during the day when the outside temperature rises, and decreases during the night when the outside temperature falls. Therefore, the capacity required for the cooling system varies with time as shown in FIG.

  In a cooling system that does not have the first reservoir and the second reservoir, the load on the compressor needs to be changed according to the change in capacity required for the cooling system (FIG. 3). For this reason, the operation of the engine, which is the driving source of the compressor, also needs to be changed according to the change in capacity required for the cooling system, and the energy efficiency of the engine is reduced.

  On the other hand, in the cooling system of the present invention, the engine can be stably operated in an efficient state by the first storage device and the second storage device, as in a hybrid vehicle. Basically, the engine is operated in an efficient state (FIG. 4). If necessary, on-off is switched according to the load required for the cooling system. When the capacity of the compressor is higher than the load required for the cooling system, the liquid refrigerant corresponding to the portion represented by E in FIG. 4 is stored in the first reservoir. When the liquid refrigerant is stored in the first reservoir, the amount of refrigerant supplied to the compressor via the evaporator decreases, but this reduced amount releases the gas refrigerant stored in the second reservoir. Make up by doing. On the contrary, when the capacity of the compressor is lower than the load required for the cooling system, or when the compressor is stopped, the liquid refrigerant stored in the first reservoir is discharged, and the evaporator Increase the amount of refrigerant that evaporates. And in order to make the load concerning a compressor constant, the quantity of a refrigerant | coolant equivalent to the refrigerant | coolant discharged | emitted from the 1st store is stored in a 2nd store. That is, the engine is operated in an efficient state, and excess cooling energy (E in FIG. 4) is stored to satisfy the shortage (F in FIG. 4).

  With such a cooling system, even when the load on the cooling system fluctuates, it is possible to drive the engine with high energy efficiency and increase the energy efficiency of the entire cooling system. In addition, the cooling system of the present invention has an advantage that rapid cooling is possible. If a method of storing a certain amount of liquid in the first reservoir and evaporating with an evaporator at the start of cooling, it is possible to start cooling immediately regardless of the time required for starting and stabilizing the engine. is there. Therefore, the system of the present invention is effective when rapidly cooling a room that has not been used, or when cooling a room where people come and go. As another example in which the present invention is effectively utilized, a case where the interior of a vehicle parked under a hot sun is rapidly cooled can be considered. When the interior of a vehicle that has been heated to a high temperature is cooled, the required cooling capacity cannot be exhibited, and it often occurs that the vehicle reaches the destination when the interior becomes comfortable. The system of the present invention can quickly follow such load fluctuations.

  Next, the configuration requirements of the present invention will be described in detail.

  The cooling system itself composed of the compressor 10, the condenser 20, the expansion valve 30, and the evaporator 40 is a known system, and is not particularly limited in the present invention. The specific device configuration such as the type and size of each device can be determined by referring to known technical matters regarding the existing refrigerant cycle and cooling cycle. For example, the knowledge described in Non-Patent Document 1 can be referred to. Newly obtained knowledge may be incorporated into the apparatus. In determining the apparatus configuration, it is preferable to consider the refrigerant to be used. For example, when carbon dioxide is used as a refrigerant, it is preferable to install a compressor or heat exchanger having a high-pressure design in consideration of the low critical point temperature of carbon dioxide of about 31 ° C./7.38 MPa.

  The refrigerant is not particularly limited as long as it is a material that acts as a refrigerant in an environment where the cooling system is installed. Specific examples of the refrigerant include hydrocarbons such as carbon dioxide, ammonia, propane and butane, water, air, HFC, HCFC, and the like. Considering the influence on the environment, natural refrigerants such as carbon dioxide, ammonia, hydrocarbons, water, and air are preferable, and carbon dioxide is more preferable. Carbon dioxide has an ozone depletion coefficient of zero, and the global warming coefficient is about a thousandth that of the refrigerant HFC. Carbon dioxide also has characteristics such as harmless to human body, non-flammability, non-corrosion, and thermal stability. The current air-conditioning and refrigeration / refrigeration systems use chlorofluorocarbon-based refrigerants, and as a transient method that can be replaced by natural refrigerants such as carbon dioxide, chlorofluorocarbon-based refrigerants are adsorbed to gas storage materials using the same concept. Is also possible.

The first reservoir 60 is not limited as long as it can store a liquid refrigerant. Various means capable of holding the refrigerant used in a liquid state can be used. For example, when carbon dioxide is used as the refrigerant, a liquid CO ₂ cylinder can be used. As described above, when the refrigerant in the state B is a gas, the first reservoir 60 is preferably a device that can store the refrigerant in the gas state. For example, a high-pressure cylinder capable of storing a gas refrigerant is used.

  The size of the first reservoir may be determined in accordance with the size of the cooling system, the degree of fluctuation in capacity required for the cooling system, the operating state of the engine, and the like. The larger the size of the cooling system, the larger the size of the first reservoir. When the fluctuation in capacity required for the cooling system is large, the amount of the liquid refrigerant stored in the first reservoir increases, so that the size of the first reservoir also increases. In addition, when the engine on-off interval is long, the amount of liquid refrigerant stored in the first reservoir tends to increase, and the size of the first reservoir also increases.

  The delivery of the liquid refrigerant between the pipe connecting the condenser 20 and the expansion valve 30 and the first reservoir 60 can be controlled using a valve, for example. Specifically, the flow rate of the refrigerant can be controlled by arranging pressure sensors before and after the valve and controlling the differential pressure. In order to control the flow rate with higher accuracy, it is also possible to arrange a pump for liquid refrigerant or gas refrigerant on the outlet side of the valve.

  The second reservoir 70 is not limited as long as it can store a gaseous refrigerant. In order to efficiently store the gas in the second reservoir, it is preferable to use the second reservoir in which the gas adsorbent is disposed. A conventionally well-known technique can be used for the structure and material of the container which accommodates a gas adsorbent, and it is not specifically limited. A metal container or the like that can control the delivery of the gas refrigerant between the pipe connecting the evaporator 40 and the compressor 10 and the second reservoir 60 by the valve control is used. Moreover, what wound the carbon fiber reinforced plastic material excellent in the intensity | strength per unit density to the outer surface of a metal thin container may be used. If the container is provided with a regulating valve for controlling the internal pressure of the second reservoir, the regulating valve can be utilized when gas is released from the second reservoir.

  Similar to the first reservoir, the size of the second reservoir may be determined according to the size of the cooling system, the degree of fluctuation in the capacity required for the cooling system, the operating state of the engine, and the like. The larger the size of the cooling system, the larger the size of the second reservoir. When the fluctuation of the capacity required for the cooling system is large, the amount of the gas refrigerant stored in the second reservoir increases, so that the size of the second reservoir also increases. In addition, when the engine on-off interval is long, the amount of gas refrigerant stored in the second reservoir tends to increase, and the size of the second reservoir also increases.

  The method for accommodating the gas adsorbent is not particularly limited, and a known method such as filling into a pressure vessel can be used. What is necessary is just to determine the accommodation amount of a gas adsorbent according to the gas storage capacity calculated | required by a 2nd store. The shape and material of the pressure vessel are not particularly limited. In the case of using the present invention, it is possible to secure the same storage amount as in the conventional case at a lower pressure, and therefore it is not necessary to provide a special pressure resistant structure. In this respect, it can be said that there is an advantage in cost.

  When the gas adsorbent is in a powder form, there is a possibility that the gas adsorbent cannot be filled well if it is stored in a container constituting the second reservoir. When using a tank having a high degree of freedom in shape, this problem may be particularly noticeable. In this case, the powder may be stored in a tablet shape. In the case of using a tablet-shaped product, it is excellent in handleability and is very convenient when replacing an aged compound.

The type of gas adsorbent is not particularly limited, but in order to reduce the occupied volume of the second reservoir and reduce the size of the entire cooling system, use a gas adsorbent with a high gas storage amount per unit volume. Is preferred. As the gas adsorbent, activated carbon, zeolite, and the like are known. Preferably, a compound in which the adsorption / desorption isotherm regarding the refrigerant exhibits a hysteresis loop is used. The compound exhibiting a hysteresis loop has been confirmed to have a very high gas adsorbability such that the volume of 1 g of carbon dioxide under one atmosphere pressure of 20 ° C. is 3.1 cm ³ , and is useful as a gas adsorbent. Incidentally, when the volume of 1 g of carbon dioxide under 1 atm. 20 ° C. is exemplified, the gaseous CO ₂ gas is 520 cm ³ and the liquefied carbonic acid is 1 cm ³ .

  Subsequently, a compound in which the adsorption / desorption isotherm regarding the gas refrigerant exhibits a hysteresis loop will be described. The compound in which the adsorption / desorption isotherm regarding the gas refrigerant exhibits a hysteresis loop is a material in which the gas pressure-gas adsorption amount curve at the time of adsorption and the gas pressure-gas adsorption amount curve at the time of desorption are different as shown in FIG. .

  FIG. 5 is a graph showing the relationship between the gas pressure and the gas adsorption amount in the gas adsorbent showing a hysteresis loop. FIG. 6 is a graph showing the relationship between gas pressure and gas adsorption amount in a general gas adsorbent. In the figure, the horizontal axis indicates the gas pressure, and the vertical axis indicates the gas adsorption amount per unit mass of the adsorbent. The gas pressure-gas adsorption amount curve is also referred to as an adsorption / desorption isotherm in the present application.

  In the conventional gas adsorbent, the gas adsorption amount increases as the gas pressure increases, and the pressure-adsorption amount curve during adsorption coincides with the pressure-adsorption amount curve during desorption (FIG. 6).

In the gas adsorbent exhibiting a hysteresis loop, the adsorption / desorption isotherm is completely different (FIG. 5). It begins adsorption and the gas pressure is P _2, a gas adsorption amount with P ₁ increases rapidly to A _1. When vacuum this desorption starts at P _3, the gas adsorption amount with P ₄ is reduced to A _2. By selecting the gas adsorbing material, P _{1 to} P ₄ which are the adsorption / desorption performance can be arbitrarily selected. In the case of this system, since the refrigerant exits the evaporator 40 via the expansion valve 30 and is stored in a gas state, the gas adsorption pressure P ₁ is preferably lower than the pressure of the evaporator 40. If there is no appropriate adsorbent due to the type of refrigerant or heat cycle, a small gas compressor may be installed in front of the second reservoir 70 and the gas pressure adjusted to an appropriate pressure.

  Note that the hysteresis loop shown in FIG. 5 is an example of the hysteresis loop, and the shape of the hysteresis loop is not limited to the illustrated shape. The shape of the hysteresis loop is not particularly limited as long as the pressure-adsorption amount curve during adsorption is different from the pressure-adsorption amount curve during desorption, and efficient gas adsorption / desorption can be performed.

Gas desorption pressure _{P 4} and the pressure difference _P 1 -P ₄ of a gas adsorption pressure _{P 1} is preferably small. In the case of a conventional gas adsorbent, as shown in FIG. 6, in order to desorb the gas adsorption amount from A ₁ to A ₃ , it is necessary to reduce the gas pressure from P ₁ to P ₅ . Since P ₁ -P _{4 in} FIG. 5 is smaller than the pressure difference P ₁ -P ₅ , adsorption / desorption can be effectively caused. For these reasons, in order to increase the efficiency of adsorption / desorption, it is preferable that the differential pressure between adsorption and desorption is small.

  The adsorption characteristics, composition and structure of the gas adsorbent used in the present invention will be described.

  The gas adsorbent used in the present invention is preferably a material in which an adsorption / desorption isotherm related to gas exhibits a hysteresis loop. A material that exhibits a hysteresis loop may exhibit a hysteresis loop at least with respect to a gas refrigerant, and may not exhibit a hysteresis loop for all gases.

  Examples of the material in which the gas adsorption / desorption isotherm shows a hysteresis loop include a polymer complex represented by the following chemical formula 1.

  In Chemical Formula 1, X represents a divalent transition metal ion, Y represents an anion, and L represents an organic ligand having two coordination sites. a is 2 when L is not charged and Y is a monovalent anion, 1 when L is not charged and Y is a divalent anion, and L is charged monovalently. And m is 0 or 0.5 or more and 8 or less.

  The compound represented by Chemical Formula 1 can be produced using the following compounds as raw materials.

One of the raw material is a metal salt, a compound represented by XY _a. Examples of X include divalent transition metal ions such as iron, cobalt, nickel, copper, and zinc ions. In terms of ease of making a complex, ions of cobalt, nickel, copper, and zinc are preferable, and ions of nickel and copper are more preferable.

Y is a monovalent or divalent anion, and examples of the monovalent anion include Cl ⁻ , Br ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ and CF ₃ CO ₂ ⁻ . Examples include strong acid acid ions. BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , and more preferably BF ₄ ⁻ , PF ₆ ⁻ , and CF ₃ SO ₃ ⁻ are mentioned in terms of ease of making the complex. Examples of the divalent anion include SiF ₆ ²⁻ , GeF ₆ ²⁻ , SbF ₆ ²⁻ , SO ₄ ^{2− and the} like. SiF ₆ ²⁻ and SO ₄ ²⁻ are preferable in terms of ease of forming the complex.

As another raw material, the organic ligand L is used. L is a ligand having two coordination sites at relatively distant positions in the molecule. That is, it is an ABA (A = 4-pyridyl group) type ligand having 4,4′-bipyridyl and one 4-pyridyl group at both ends of the molecule. As B, —CH ₂ —, —CH═CH— (cis or trans), —CO—NH—, 1,4-phenylene or substituted phenylene, 1,3-phenylene or substituted phenylene, 2,5-thiophenyl or The substitution product, 2,7-fluorenyl or the substitution product thereof, 1,4-diethynylbenzene and the like can be mentioned. 4,4′-bipyridyl, 1,4-bis (4-pyridyl) benzene, 1,4-bis (4-pyridyl) thiophene and 1,4-bis (4-pyridyl) are relatively inexpensive ) Acetylene is preferable, and 4,4′-bipyridyl is preferable because it is easily available as a general-purpose product.

  Since the polymer complex is a substance having polarity, it may include water, alcohol, ether or the like. M representing the number of water molecules to be included varies from 0.5 to 8, and reversibly changes depending on the environment in which the complex is stored. In addition, these are only weakly bonded to the polymer complex, and may be removed by a treatment such as drying under reduced pressure, and m may be 0. In such a case, water such as represented by Chemical Formula 2 may be used. It may change to a complex that does not contain.

  In Chemical Formula 2, X represents a divalent transition metal ion, Y represents an anion, and L represents an organic ligand having two coordination sites. a is 2 when L is not charged and Y is a monovalent anion, 1 when L is not charged and Y is a divalent anion, and L is charged monovalently. 0 if it is.

  However, the complex represented by Chemical Formula 2 returns to the complex represented by Chemical Formula 1 by absorbing moisture. Therefore, even a complex represented by Chemical Formula 2 can be regarded as essentially the same as the polymer complex used in the present invention.

  As another material in which the adsorption / desorption isotherm regarding gas exhibits a hysteresis loop, a polymer complex represented by the following chemical formula 3 can be mentioned.

  In Chemical Formula 3, X represents a divalent transition metal ion, C represents an aromatic carboxylic acid ligand, and L ′ represents a non-carboxylic acid type ligand having two coordination sites.

  The compound represented by Chemical Formula 3 can be produced using the following compounds as raw materials.

  One of the raw materials is a metal salt containing a transition metal ion X. X may be a divalent transition metal ion such as iron, cobalt, nickel, copper, or zinc ion. In terms of ease of making a complex, ions of cobalt, nickel, copper, and zinc are preferable, and ions of nickel and copper are more preferable.

Examples of the counter ion of X include a monovalent or divalent anion. For example, Cl ⁻ , Br ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , and CH ₃ CO _2. ⁻ , NO ₃ ⁻ , SiF ₆ ²⁻ , GeF ₆ ²⁻ , SO ₄ ^{2−, and the} like. BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , CH ₃ CO ₂ ⁻ , NO ₃ ⁻ , SiF ₆ ²⁻ , GeF ₆ ²⁻ , SO ₄ ^2- , more preferably BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ CO ₂ ⁻ , CH ₃ CO ₂ ⁻ , and NO ₃ ⁻ . These counter ions may be used alone or in combination. For example, when a copper salt is used as the metal salt, Cu (BF ₄ ) ₂ may be used alone, or Cu (BF ₄ ) ₂ and Cu (OAc) ₂ may be mixed and used. The mixing ratio may be arbitrary.

  C is an aromatic carboxylic acid-based ligand. An aromatic carboxylic acid-based ligand refers to a compound in which one or more carboxyl groups are substituted on an aromatic group.

  Examples of ligands substituted with one carboxyl group include 2-hydroxybenzoic acid containing no functional groups other than carboxyl groups or functional groups other than carboxyl groups such as benzoic acid and 4-carboxybiphenyl. 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4 -Aminobenzoic acid, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2,4 -Dimethoxybenzoic acid, 2,5-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 4-acetoxybenzoic acid, 2,4-diacetoxybenzoic acid Acid, 2,5-diacetoxy benzoic acid, 4-acetyl benzoic acid, 2,4-diacetyl-benzoic acid can be exemplified widely 2,5 diacetyl benzoate.

  Examples of ligands containing two or more carboxyl groups include terephthalic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid, 4,4′-biphenyldicarboxylic acid, 2,5-dimethylterephthalic acid. Etc. can be illustrated. In these carboxylic acid-based ligands, one of the carboxyl groups is ionized during coordination and coordinated as a carboxylic acid anion. From the viewpoint that the compound can be obtained relatively inexpensively and the stability of the compound is high, a benzoic acid substituted with a hydroxy group or a methoxy group, an unsubstituted benzoic acid, terephthalic acid, or 4,4'-biphenyldicarboxylic acid is preferable.

Another raw material is a non-carboxylic acid type ligand L ′. L ′ is a ligand having two coordination sites that are not carboxyl groups at relatively distant positions in the molecule. That is, it is 4,4′-bipyridyl or an ABA (A = 4-pyridyl group) type ligand having one 4-pyridyl group at both ends of the molecule. B is —CH ₂ —, —CH═CH— (cis or trans), —CO—NH—, 1,4-phenylene or substituted phenylene, 1,3-phenylene or substituted phenylene, 2,5-thiophenyl or the like A substituted body, 2,7-fluorenyl or its substituted body, 1,4-diethynylbenzene, etc. are mentioned. 4,4′-bipyridyl, 1,4-bis (4-pyridyl) benzene, 1,4-bis (4-pyridyl) thiophene, 1,4-bis (4-pyridyl) are relatively inexpensive. ) Acetylene is preferred, and 4,4′-bipyridyl is preferred because it is readily available as a general-purpose product.

[XA ₂ L ′ ₂ ] As an example of the steric structure of the _n- type polymer complex, a mode in which linear main chains are aggregated or a lattice structure can be considered, but any of them may be used.

  Similar to the polymer complex represented by Chemical Formula 1, the polymer complex is a substance having polarity, so when it comes into contact with organic molecules such as water, alcohol or ether, it contains water or an organic solvent. In some cases, water or an organic solvent is inserted between the ion and the ligand, and for example, the complex may be changed into a complex complex represented by Chemical Formula 4.

  In Chemical Formula 4, X represents a divalent transition metal ion, D represents a benzoic acid-based ligand, and L ′ represents a non-carboxylic acid type ligand having two coordination sites. Z represents a low molecule such as water, alcohol or ether, and m is 0.5 or more and 8 or less.

  However, organic molecules such as water, alcohol and ether in these complex complexes are only weakly bonded to the polymer complex, and are removed by a treatment such as drying under reduced pressure to return to the complex represented by Chemical Formula 3. Therefore, even a complex represented by Chemical Formula 4 can be regarded as essentially the same as the polymer complex used in the present invention.

  The polymer metal complex of Chemical Formulas 1-4 is a polymer body having a structure in which the unit structures represented by Chemical Formulas 1-4 are repeated. In the chemical formulas 1 to 4, n indicates that the unit structure of the chemical formulas 1 to 4 is repeated, as in the case of general polymer compounds, and the range of n is not particularly limited. The molecular weight of the polymer compound is not particularly limited. For example, the polymer metal complexes of Chemical Formulas 1 to 4 have a number average molecular weight of 1000 or more.

The gas adsorbents represented by the chemical formulas 1 to 4 may be selected according to the gas to be stored and the pressure required at the time of adsorption. Although not particularly limited, specific examples include [Cu (BF ₄ ) ₂ (bpy) ₂ ] _n (where bpy represents 4,4′-bipyridyl), [Ni (BF ₄ ) _{2 (BP1P) 2] n} (wherein, BP1P is 1,4-bis (4-pyridyl) represents a _benzene) include _{[Cu (CF 3 SO 3)} 2 (bpy) 2] n.

  The polymer metal complex can be obtained by mixing a metal salt as a raw material and a ligand in a solvent. At this time, it is preferable to use a non-aqueous solvent as the metal salt solvent. When an aqueous solvent is used as a solvent, a water-containing complex may be formed (see Kitagawa, S., J. Chem. Soc., Dalton Trans., (1999) 1569). If water is mixed in a solvent that dissolves metal salts and organic ligands, a water-containing complex may be formed. The yield of is difficult to decrease. In the production method of the polymer metal complex, known documents such as JP-A-2004-74025 may be referred to.

  The vapor compression heat pump system of the present invention can be applied to various applications that require heating and / or cooling. For example, an air conditioning system for heating and / or cooling a room, a vehicle air conditioning system, and the like can be given. The liquid may be heated and / or cooled using the endotherm in the evaporator.

  Assuming the case where it is used as a home air conditioning system with 3 rooms between 6 mats, the required size of the second and first reservoirs was estimated. The refrigerant assumed carbon dioxide. The size of the reservoir was determined as the size required to operate the air conditioning system for 1 hour without operating the compressor.

The size of the room to be cooled is 6 (tatami) × 3 (room) ≈10 (m ² ) × 3 = 30 (m ² ). Assuming that the cooling load at home is 100 (kcal / hr) per 1 (m ² ), the cooling load required per hour is 100 (kcal / hr · m ² ) × 30 (m ² ) = 3000 ( kcal / hr). From the Mollier diagram, the enthalpy difference of carbon dioxide is (740−550) × 0.239 = 45.4 (kcal / kg). Therefore, the carbon dioxide storage amount for cooling for 1 hour is 3000 (kcal) /45.4 (kcal / kg) = 66 (kg).

In the gas storage device, if a polymer metal complex having a volume of 3.1 cm ³ of carbon dioxide (1 g) at 1 atm and 20 ° C. as a gas adsorbent is disposed, the size of the required gas storage device is large. The size is 198 liters. This corresponds to a container of about 1 m × 1 m × 20 cm. If it is this size, it is easy to arrange under the floor or the ceiling.

The size of the liquid storage device is 66 liters considering that the specific gravity of carbon dioxide is 1.03 g / cm ³ . This corresponds to a cylinder having a diameter of 24 cm and a height of about 1 m.

It is a conceptual diagram of the cooling cycle of this invention. The horizontal axis shows the enthalpy of the refrigerant, and the right side shows that the enthalpy of the refrigerant is higher. The vertical axis indicates the pressure, and the higher the pressure, the higher the pressure of the refrigerant. It is a graph which shows the relationship between time and the capability requested | required of a cooling system. It is a graph which shows the relationship between time and the load concerning a compressor in the cooling system which does not have a 1st store and a 2nd store. It is a graph which shows the relationship between time and the load concerning a compressor in the cooling system which has a 1st store and a 2nd store. It is a graph which shows the relationship between the gas pressure and gas adsorption amount in the gas adsorbent which shows a hysteresis loop. It is a graph which shows the relationship between the gas pressure and gas adsorption amount in a common gas adsorbent.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Compressor, 20 ... Condenser, 30 ... Expansion valve, 40 ... Evaporator, 50 ... Pipe, 60 ... 1st reservoir, 70 ... 2nd reservoir.

Claims (4)

A vapor compression heat pump system including a refrigerant cycle in which an engine-driven compressor, a condenser, an expansion valve, and an evaporator are arranged in this order,
A refrigerant pipe connecting the condenser and the expansion valve is connected to a first reservoir that stores liquid refrigerant or gas refrigerant,
A vapor compression heat pump system in which a second storage for storing a gas refrigerant is connected to a refrigerant pipe connecting the evaporator and the compressor.   The vapor compression heat pump system according to claim 1, wherein the refrigerant is carbon dioxide.   The vapor compression heat pump system according to claim 1 or 2, wherein the second reservoir is provided with a compound in which an adsorption / desorption isotherm relating to the refrigerant exhibits a hysteresis loop.   The vapor compression heat pump system according to any one of claims 1 to 3, wherein the vapor compression heat pump system is an air conditioning system that reduces an indoor air temperature by absorbing heat in the evaporator.

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