JPS59219658A - Heat pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to heat pumps for room air conditioners, hot water supply equipment, etc., and particularly to heat pumps intended for high-temperature space heating and high-temperature hot water supply.

[Background of the invention]

First, a conventional heat pump will be explained.

FIG. 1 is a cycle configuration diagram showing an example of a conventional heat pump, and FIG. 2 is a Mollier diagram of the heat pump according to FIG. 1.

In FIG. 1, 1 indicates a refrigerant (for example, a low boiling refrigerant 11
L22) A compressor that boosts the pressure of gas; 2 is a condenser that releases heat from the refrigerant that has become high temperature and high pressure in the compressor 1; 3 is a pressure reducer that reduces the pressure of the refrigerant condensed in the condenser 2; 4 is an evaporator that pumps heat from a heat source (for example, the atmosphere).

When the compressor 1 of the heat pump configured as described above is driven, the pressure of the refrigerant is increased in the compressor 1, the pressure is reduced in the pressure reducer 3, and the heat is pumped up from the heat source in the evaporator 4 and sent to the compressor 1. Cycle back.

The heating capacity when
2), and the compression work is indicated by the value of (11'o).

However, io and 11.1□ are the enthalpies of the refrigerant at the compressor inlet, compressor outlet, and condenser outlet, respectively.

The coefficient of performance of this heat pump is expressed as the ratio of heating capacity to compression work. That is, ('+ '2)/(
1+ io) In order to obtain a high temperature in this heat pump, it is necessary to increase the discharge pressure of compressor 1 to create a cycle as shown by the broken line in Figure 2, but in this way, the evaporation pressure (evaporation temperature) and condensation The difference from the pressure (condensation temperature) increases, and the compression work increases.As the condensation pressure increases, the latent heat of the refrigerant decreases. The coefficient of performance in this case is (+1 14)/('+' io), which is lower than the coefficient of performance described above. That is, there was a drawback in that when the discharge pressure of the compressor 1 was increased in order to obtain a high temperature, the coefficient of performance decreased.

Moreover, since it is necessary to increase the pressure resistance of the compressor 1, the compressor 1 becomes thicker and weighs more, resulting in higher costs.

Furthermore, when the discharge pressure of the compressor 1 is increased, the refrigerant and the lubricating oil of the compressor 1 are thermally decomposed, resulting in a problem that the reliability of the heat pump is reduced.

As a means to solve the above-mentioned problems, a high boiling point refrigerant (for example, It 12 ) is added to a low boiling point refrigerant (for example, R22).
Attempts have been made to use non-azeotropic mixed refrigerants with added . By using this mixed refrigerant, a lower condensing pressure (-compressor discharge pressure) is required to obtain the same high temperature than when using a conventional single refrigerant, that is, a low boiling point refrigerant. Although there are no problems with the pressure resistance of the machine or thermal decomposition of the refrigerant or lubricating oil, the coefficient of performance is still lower than the coefficient of performance ('+-12)/('+'o). The high boiling point refrigerant has a smaller latent heat per unit volume of saturated vapor at the same temperature than the low boiling point refrigerant,
In order to obtain the same heating capacity, it is necessary to increase the capacity of the compressor 1, that is, the size of the compressor 1 has to be increased, which is a problem, and at present it has not been put into practical use.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art described above and provides high-temperature heating with an excellent coefficient of performance and high reliability.

The purpose is to provide a heat pump suitable for high-temperature hot water supply.

[Summary of the invention]

The structure of the heat pump according to the present invention is a compressor.

In a heat pump that connects a condenser, a pressure reducer, and an evaporator in sequence and uses a non-azeotropic mixed refrigerant made by mixing refrigerants with different boiling points, a gas-liquid separator with a filling inside is connected to the condenser. A bypass circuit is provided in the middle, which is equipped with a heater that heats the gas-liquid separator, and which is capable of guiding the liquid refrigerant separated by the gas-liquid separator to the compression chamber of the compressor, and is equipped with a pressure reducer in the middle. It was designed to be provided.

[Embodiments of the invention]

Hereinafter, the present invention will be explained by examples.

FIG. 3 is a cycle configuration diagram of a heat pump according to an embodiment of the present invention, FIG. 4 is a vapor-liquid equilibrium diagram under constant pressure conditions of a non-azeotropic mixed refrigerant used in the heat pump according to FIG. 3,
FIG. 5 is a Mollier diagram of the heat pump according to FIG. 3.

In FIG. 3, the same numbers as in FIG. 1 indicate the same parts. 2 are condensers with a gas-liquid separator 5 installed between them; 3A is a first pressure reducer related to a pressure reducer installed between the two condensers and the evaporator 4; 9 is a a bypass circuit that guides the liquid refrigerant separated by the gas-liquid separator 5 (the refrigerant used will be described in detail later) to the compression chamber 1a of the compressor (2);
6 is a second pressure reducer related to a pressure reducer provided in the middle of this bypass circuit 9.

The refrigerant used is a mixed refrigerant of two types of refrigerants with different boiling points (for example, a non-azeotropic mixed refrigerant υ1 formed by mixing a low-boiling point refrigerant 11.22 and a high-boiling point refrigerant 1 (, 12)), and this non-azeotropic mixed refrigerant FIG. 4 is a vapor-liquid equilibrium diagram under constant pressure conditions. This fourth
In the figure, the horizontal axis represents the mole fraction of the low boiling point refrigerant (R, 22), and the vertical axis represents the temperature. ■ is the boiling point of the high boiling point refrigerant (ai2), J is the boiling point of the low boiling point refrigerant (R22), the solid line J and the I3J bow J are the gas phase line, and the broken line IHGCFJ is the liquidus line. Hereinafter, the non-azeotropic mixed refrigerant will be simply referred to as a refrigerant.

The operation of the heat pump configured in this way will be explained using FIGS. 3 to 5. In the Morigol diagram in Figure 5,
The same symbols as in FIG. 4 indicate the same states.

When the compressor 1 is driven, the pressure of the refrigerant increases, and at the outlet of the compressor 1, a gas refrigerant with a temperature and pressure of .

This gas refrigerant enters the condenser 2A, starts dissipating heat, lowers the temperature, and condenses the refrigerant of composition 11 at point B. Thereafter, the refrigerant further radiates heat and condenses, and enters the gas-liquid separator 5 in this state. The composition of the gas refrigerant at this time is represented by E, and the composition of the liquid refrigerant is represented by G.

The ratio of liquid refrigerant to gas refrigerant is expressed by the ratio of the lengths of DE and DG. When all of the liquid refrigerant in the gas-liquid separator 5 flows toward the second pressure reducer 6, the ratio I is DE/GE. The gas refrigerant separated in the gas-liquid separator 5 further radiates heat in the condenser 2A, lowers its temperature, reaches the lit point, and enters the first pressure reducer 3A. Therefore, the gas refrigerant after the gas-liquid separator 5 has a composition of low boiling point refrigerant that is increased by X when the liquid refrigerant is removed from the middle of the condenser 2A. And the first pressure reducer 3A
The depressurized refrigerant is pumped up from the surroundings in the evaporator 4 to become a low-temperature, low-pressure gas refrigerant and returned to the inlet J of the compressor 1, where it is again pressurized and heated. On the other hand, the liquid refrigerant of composition G separated by the gas-liquid separator 5 is depressurized by the second pressure reducer 6 and enters the compression chamber la of the compressor 1, where the adiabatically compressed gas coming from the evaporator 4 Cool the refrigerant.

The heat radiation amount Q in the condenser 2A of this heat pump is determined by the following equation.

Q=A-iG-(1-i)F The refrigerant whose pressure has been reduced in the first pressure reducer 3A is -
, 1- of heat is pumped up from the surroundings. Then, the compressor 1 performs adiabatic compression at 1 (from A'!), but the enthalpy decreases once by Mt due to the liquid refrigerant passing through the second pressure reducer 6 at point L. At this time, the compression work of the heat pump W is calculated using the following formula.

W2(1-i)(L-K)-1-(A-M) Therefore, the coefficient of performance CQp can be calculated using the following formula.

cop =Q/W-(A,-1G-(1-i)F)/
+ (1-i) (L-10+(A-M)) By the way, as previously attempted, all the refrigerant (non-azeotropic mixed refrigerant) is transferred to the pressure reducer 3. Compared to the case where it flows into the evaporator 4 (the Mollier diagram in this case is shown by the broken line in Fig. 5), the amount of heat released from the condenser 2A is smaller by an amount corresponding to A'-A, but this is due to I( This is only offset by the decrease in the amount of refrigerant compressed by the L dimension.In addition, the evaporation pressure in the evaporator 4 changes by Δp because the composition of the refrigerant changes by X and the composition of the low boiling point refrigerant increases. , the compression work decreases.

Therefore, the coefficient of performance of this example is that all the refrigerant (non-azeotropic mixed refrigerant) is transferred to the pressure reducer 3. This is improved compared to the case of flowing to the evaporator 4, and the desired coefficient of performance can be obtained, which is almost equal to the coefficient of performance ('+!2)/(j+-Io) of the cycle indicated by the solid line in Fig. 1 described above. .

The amount of heat released to the condenser 2 is reduced by the amount equivalent to A/A, but since this area is superheated steam,
The outlet temperature of the compressor 1 decreases by this amount t/, and there is no adverse effect on the refrigerant or lubricating oil.

Furthermore, since gas-liquid separation is performed between the two condensers and the liquid refrigerant is returned to the compression chamber 1a of the compressor 1, the compressor 1
The lubricating oil that comes out is separated together with the liquid refrigerant in the gas-liquid separator 5 and returned to the compressor 1. Therefore, less lubricating oil is taken out into the cycle, improving the reliability of the compressor 1, increasing the condensation and evaporation heat transfer coefficients, and further improving the coefficient of performance.

In addition, the composition of the refrigerant in the compressor 10 population also changes, and the composition of the low boiling point refrigerant increases, so compared to the case where all the refrigerant (non-azeotropic mixed refrigerant) is circulated, the refrigerant composition in the compressor 10 population changes.
Since the specific volume of the gas refrigerant sucked into the compressor 1 becomes smaller,
The size of the refrigerant may be the same as when a single refrigerant is used, and there is no need to increase the size just because a mixed refrigerant is used.

According to the embodiment described above, a non-azeotropic mixed refrigerant is used, and the separated liquid refrigerant is guided to the compression chamber 1a of the compressor 1 by the gas-liquid separator 5 provided in the middle of the condenser 2A. So,
A high temperature can be obtained without increasing the outlet temperature of the compressor 1,
It also has an auspicious effect of having an excellent coefficient of performance. In addition, less lubricating oil is carried out into the cycle, and the compressor 1
This will improve the reliability of heat pumps and further improve the coefficient of performance of heat pumps.

FIG. 6 is a cycle configuration diagram of a heat pump according to another embodiment of the present invention, and FIG. 7 is a vapor-liquid equilibrium diagram of a non-azeotropic mixed refrigerant used in the heat pump according to FIG. 6 under constant pressure conditions.
It is a diagram.

In Figures 6 and 7, the same numbers as in Figures 3 and 4, respectively,
Items with the same symbols indicate the same parts and conditions. 5a is a gas-liquid separator 5A installed in the middle of the condenser 2B.
7. A filling for promoting mass transfer, which is filled in the inside.
is a heater that heats the gas-liquid separator 5A.

The operation of this embodiment configured in this way will be explained using FIGS. 6-7. The heat pump shown in FIG. 3 is the same as the heat pump shown in FIG. 3 until it enters the gas-liquid separator 5A.

The liquid refrigerant that has entered the gas-liquid separator 5A exchanges heat with the filling 5a heated by the heater 7, and falls to the bottom while evaporating the low boiling point refrigerant. The composition of the liquid refrigerant at this time is
The temperature of the filling material 5a varies depending on the gas phase line composition G't. Therefore, the composition of the gas refrigerant becomes No. 1', and by removing the liquid refrigerant from the middle of the condenser 2B, X' (X in Figure 4
As the composition of the low boiling point refrigerant increases (larger), the evaporation pressure of the evaporator 4 becomes even greater than that of the heat pump according to FIG. 3. This has the effect of making the compression work smaller and further improving the coefficient of performance.

FIG. 8 is a cycle configuration diagram of a heat pump according to still another embodiment of the present invention.

In FIG. 8, the same parts as those in FIG. 3 are denoted by the same numbers. Reference numeral 8 denotes a two-way valve provided between the gas-liquid separator 5 and the second pressure reducer 6 on the bypass circuit 9. By turning off the two-way valve 8, liquid is transferred to the bypass circuit 9. This makes it possible to stop the flow of refrigerant.

If the heat pump configured in this way is used as a room air conditioner, when the outside air temperature becomes high, the amount of heat dissipated can be reduced by turning off the two-way valve 8 and allowing the entire amount of refrigerant to flow toward the first pressure reducer 3A. It can be reduced. That is,
As the outside temperature rises, the amount of heat required for two condensers to dissipate becomes smaller. Also, at this time, the evaporation temperature rises, and the difference between it and the condensation temperature decreases, resulting in less compression work. As a result, the temperature of the gas refrigerant at the outlet of the compressor 1 decreases.

From this, if the bypass circuit 9 is turned OFF to circulate the entire amount of refrigerant and a gas refrigerant with a large amount of high boiling point refrigerant is used at the inlet of the compressor 1, the capacity of the compressor 1 can be reduced, and the condenser The amount of heat dissipated at 2A can be reduced.

In this embodiment, the two-way valve 8 is provided between the gas-liquid separator 5 and the second pressure reducer 6, but it is also provided between the second pressure reducer 6 and the compressor 1. It's okay.

Further, in each of the above embodiments, the case where two types of non-azeotropic mixed refrigerants are used has been described, but the same effect can be obtained when three or more types of non-azeotropic mixed refrigerants are used.

〔Effect of the invention〕

As will be described in detail below, according to the present invention, it is possible to provide a heat pump that has an excellent coefficient of performance, is highly reliable, and is suitable for high-temperature heating and high-temperature hot water.

[Brief explanation of the drawing]

FIG. 1 is a cycle configuration diagram showing an example of a conventional heat pump, FIG. 2 is a Mollier diagram of the heat pump according to FIG. 1, and FIG. 3 is a cycle configuration diagram of a heat pump according to an embodiment of the present invention. , FIG. 4 is a vapor-liquid equilibrium diagram under constant pressure conditions of the non-azeotropic mixed refrigerant used in the heat pump according to FIG. 3, FIG. 5 is a Mollier diagram of the heat pump according to FIG. 3, and FIG. 7 is a diagram of a cycle configuration of a heat pump according to another embodiment of the present invention, FIG. FIG. 8 is a cycle configuration diagram of a heat pump according to still another embodiment of the present invention. ■...Compressor, 1a...Compression chamber, 2A, 2B...
Condenser, 3A--First pressure reducer, 4... Evaporator, 5
, 5A... gas-liquid separator, 5a... filling, 6...
2nd pressure reducer, 7... Heater, 8... Two-way valve, 9...
・Bypass circuit. Agent Patent attorney Kosaku Fukuda 1st mouth 3 / certain 2 mouth i2 =, MU4,4'工〉Tarhi' $3 A! 4th θ i b #, Ii Ling f 7 le minutes 10 moss 5 loeshitalko. 6th eye A

Claims (1)

[Claims] 1. A gas-liquid separator with a filling inside in a heat pump that uses a non-azeotropic mixed refrigerant, which is made by sequentially connecting a compressor, condenser, pressure reducer, and evaporator and mixing refrigerants with different boiling points. is provided in the middle of the condenser, a heater is provided to heat the gas-liquid separator, and a pressure reducer is provided in the middle, which can lead the liquid refrigerant separated by the gas-liquid separator to the compression chamber of the compressor. A heat pump characterized by having a bypass circuit.