JPS60175980A - Cooling method - 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 <Industrial Application Field> The present invention relates to a snapping force method. The invention is particularly applicable to known ejector cooling cycles and will therefore be described below with respect to its application to ejector cooling cycles.

<Problems to be Solved by the Invention and Means for Solving the Problems> An object of the present invention is to provide a novel method for improving the overall coefficient of performance (c, o, p) of a cooling cycle, particularly an ejector cooling cycle. It is about providing. Increasing c, o, p values indicate a more efficient system requiring less energy input for a given cooling load.

According to the present invention, a working fluid is evaporated to high pressure in a generator, the working fluid vapor is expanded and formed into a vapor stream that is combined with the working fluid vapor from the evaporator, and the vapor stream is condensed into a liquid and the condensed A method of cooling by means of a cooling cycle in which a portion of the liquid is returned to the generator for high pressure evaporation and another portion of the condensed liquid is expanded and passed through an evaporator to match the vapor flow. An improved cooling method is provided such that the incorporation of steam into the steam stream is enhanced by increasing the pressure of the steam before it is combined into the steam stream.

Several embodiments of the invention are described below for purposes of illustration. In one embodiment, the pressure of the vapor from the evaporator is increased by compressing the vapor before it is combined with the vapor stream. In a second embodiment, the pressure is increased by heating the steam before it is combined with the steam stream.

The latter is such that a second working fluid is evaporated in a second evaporator, compressed, condensed in a second condenser and expanded before being recycled to said second evaporator. The vapor of the second working fluid is used to heat up the vapor of the first working fluid in the first evaporator.

As shown in more detail below, both embodiments of the present invention substantially improve the c, o, p values of the refrigeration cycle. Thus, in applications where ejector cycles are appropriate, the system of the invention increases the c, o, p values of cooling cycles with only a small application of mechanical force, and in applications where normal compression cycles are appropriate. ,
However, if a separate heat source is available, the present invention may be used to reduce the mechanical energy required.

Another advantage of the two-cycle system of the present invention is that the two-cycle system can operate with two different coolants, especially if one of the two coolants is most suitable for the ejector portion of the cycle. and the other one is most suitable for the compression part of the cycle. Incorporating both the enhanced compression technique of the first embodiment and the two-cycle system of the second embodiment, in which the vapor from the first evaporator (in the ejector cycle) is compressed before being combined with the vapor stream. The above C,0,P(iIj) can be increased additively by .

<Example> The invention will now be described in detail with reference to the accompanying drawings.

In the figure, the symbol M is mass flow rate, P is pressure, T is temperature,
Q indicates the heat flow rate.

In a known ejector refrigeration cycle as shown in FIG. 1a, the high pressure evaporation takes place in a generator 1, and the steam can be expanded through a nozzle in the ejector 2. The low pressure created within the ejector forces the steam from the evaporator 3 to meet the ejector. The vapor stream leaving the ejector 2 is then cooled in the condenser 4. The liquid at the outlet of the condenser is divided into two parts.

One part is returned to the generator by pump 6. The other parts are allowed to expand through the expansion valve 57il. This results in a decrease in the temperature of the fluid in the evaporator 3, which absorbs heat from the cooling load and evaporates.

In the cycle described above, the pump only consumes mechanical energy. This amount of energy is typically less than the mechanical energy required in a compression cycle for the same cooling load.

The c, o, p value of any refrigeration cycle is defined as the ratio of the refrigeration supplied to the energy input to the cycle. Qe+QctQg is the amount of heat exchanged in the evaporator, condenser and generator, respectively. Wp is the energy required by the pump.

Thus, the C60°P value is defined by the following formula.
'ec, o, p=-Qg+Wp On the other hand, Te, Tc, and Tg are the absolute temperatures in the evaporator, #temperature supply, and generator, respectively. If the above-mentioned +J-cycle is an ideal model (reversible), the C60°P value is given by the following equation.

To・(Tg−Tc) 0・o, p ideal−De〜=Tg, (T.−Te) The actual c, o, p values obtained in the actual cycle are c, o, pyo
%fA. This is a small quality of the ejector itself! The main cause is the flow rate ratio. This mass flow ratio is defined as e W-/Mg. This ratio is the pressure inside the evaporator (Pe)
very sensitive to.

In the known compression refrigeration cycle shown in FIG. 1b,
Made? The fluid (coolant) vapor is compressed in a condenser 7;
In the condenser 7, the vapor is converted into a cold liquid by exchanging heat through the condenser. The liquid is then expanded through an expansion valve 8 which causes its temperature to decrease.

In the evaporator 9 heat is added to the refrigerant, which is then evaporated and compressed again in the compressor 10.

The c, o, and p values of the ideal model compression cycle are given by the following equations. 1 c, o, p, Model - Compression = Tc - Te In the improved ejector cycle shown in Figure 2, the mass flow ratio is increased by adding a compressor between the evaporator and the ejector.

This compressor requires a small amount of mechanical energy, as will be shown in the following description, in particular the generators 11. Edekta 12,
Evaporator 13. It includes a condenser 14, an expansion valve 15, and a pump 16. However, the improved system of FIG. 2 additionally has a compressor 17 between the evaporator 13 and the ejector 12, which compressor discharges the steam from the evaporator 13 before it is combined into the vapor stream of the ejector 12. compresses the vapor produced. The compressor 17 system requires a small amount of mechanical energy but improves the overall C, O, P values as shown by the examples described below. The table below shows a number of examples of the invention, where the mechanical energy is calculated with constant efficiency and all heat exchangers are assumed to be ideal.

Examples ~.3 relate to three types of cycles: an ideal cycle, a known ejector cycle, and an ejector cycle with improved conrusser.

In the latter case, the increase in pressure caused by the steam discharged from the evaporator 13 into the ejector 12 is considered to be 6895 mbar above the evaporator pressure. The working fluid is assumed to be R-114 (c2ct2F4°, molecular weight 170.9, boiling point 3.8°C). Furthermore, assume that the following values are used. Qe=3516 Watts, Tg=86℃, T
c = 30°C, Te = -8°C, refrigerant R-114° From Examples 1 to 3 of the table above, in the ejector cycle with improved compressor, the input mechanical energy increase 291 watts is c, o, p value from 0.251 to 0.78
It can be seen that the number increases to 2.

The novel system illustrated in FIG. 3 includes two cycles, each cycle having its own working fluid or coolant. The first cycle is comparable to the normal ejector cycle illustrated in FIG.
．． Ejector 112° includes evaporator 113, condenser 114, expansion valve 115 and bomb 116, all elements similar to corresponding elements 1, 2, 3, 4.5 and 6 in the ejector cycle illustrated in FIG. 1a. It operates.

The second cycle in the system of Figure 3, which utilizes a separate and separate working fluid or coolant, is comparable to the conventional compression cycle illustrated in Figure 1b; Elements 7, 8 . in the compression cycle illustrated in FIG. '9
Condenser 117 and expansion valve 1 corresponding to 10 and 10, respectively.
18, an evaporator 119, and a compressor 120.

However, in the two-cycle system of FIG. 3, the evaporator 113 of the ejector cycle is connected to the evaporator and condenser of the condensing system of the compression cycle, as shown schematically by a heat exchanger 121 between the evaporator 113 and the condenser 117. c, o,
The p value is increased.

The c, o, p values of the enoectacycle are also increased for the same reason. The combination system offers various advantages as described below.

■ If the enoectacycle is suitable, the new system can be used to increase the c, o, p values of the cooling cycle by kJ by applying very little mechanical force.

(If a recompression cycle is appropriate, the new system can be used to reduce the mechanical energy required if a separate heat source is available.

■ The novel stem can operate with two types of coolant, one of which is most suitable for the ejector portion of the cycle.

■ The new system can provide a second cooling temperature To if the MO is increased.

Examples 4-6 in the table above relate to typical cycles of the system illustrated in FIG.

In all these multiple cases, the ejector section is assumed to operate at R-114, and all heat exchangers, pumps, and compressors are assumed to be the same. The temperature TO of the device, including condenser 117 (of the compression cycle) and evaporator 113 (of the ejector cycle), is maintained constant at 10.1°C.

The c, o, p values are 34 from 49 watts of mechanical energy.
With an increase to 0 watts, 0.252 becomes e.g. 0.78
2 (Example 4).

It has been found that the C,o,p value may be further increased by including the increased compression technique of FIG. It is compressed before being combined with the flow. Thus, the modified system illustrated in FIG. 4 includes the addition of a compressor 130 between evaporator 113 and ejector 112 to compress the vapor from the evaporator before it is combined with the ejector vapor flow. The system is otherwise identical to the system illustrated in FIG. 3 (hence the corresponding reference numerals). Example 7 of the table above
9 summarizes the performance of the modified cycle for various types of coolant and for the same conditions described for the system of FIG. In the system illustrated in FIG. 4, the temperature To of the device including the evaporator 13 of the ejector cycle and the condenser 17 of the compression cycle is 0°C.
will be maintained. Thus, with the increase in mechanical force required from 49 watts to 261 watts in these examples, the c, o, p value increases from 0.252 (example 2) to 0.8 in the example.
01 (Example 8).

The coolants used in this table are known coolants. Thus R114 is C2Cf, 2F4. The molecular weight is 170.9°, the boiling point is 3.80°C, and R12 is CC, 42F21 molecular weight 1'20.92. The boiling point is -29.8°C, and R22 is ClO2, F2. Molecular weight 86.47. Boiling point -40,75
It is ℃.

The ejector in FIGS. 3 and 4 can be a turbo compressor that can be replaced with an ejector. Thus, steam from the generator is expanded into the turbine to provide power for the compressor of the turbocompressor.

This condenser forms a vapor stream that combines the vapor from the first evaporator. Even if the absolute conditions shown in the table change, the trends remain the same.

Margin below

[Brief explanation of drawings]

FIG. 1a is a block diagram illustrating a known ejector cooling cycle, FIG. 1b is a block diagram illustrating a compression cooling cycle, and FIGS.
FIG. 4 is a block diagram illustrating three novel cooling systems according to the present invention. 1.11,111...generator, 2,12°11
2... Ejector, 3, 9, 13, 113° 119.
...Evaporator, 4. '7. ,14,114,117...
Condenser, 5, 8, 15, 115.118... expansion valve,
6,16,116...Pump, 10,17°120.
130...Compressor, 121...Heat exchanger. Continued from page 1 Miteidor (IL) [Ltd.] 71093

Claims (1)

Claims: 1. A working fluid is evaporated to high pressure in a generator, the working fluid vapor is expanded and formed into a vapor stream that joins the working fluid vapor from the evaporator, and the vapor stream is condensed to a liquid; In a method of cooling by means of a cooling cycle in which a part of the condensed liquid is returned to the generator for high pressure evaporation and another part of said condensed liquid is expanded and passed through an evaporator to match the vapor flow. a cooling method in which the incorporation of steam into the steam stream is enhanced by increasing the pressure of the steam before it is combined into the steam stream; 2. The method of claim 1, wherein the pressure of the vapor from the evaporator is increased by compressing the vapor before it is combined with the vapor stream. 3. The working fluid vapor from the generator is expanded and formed into a vapor stream by passing the vapor through a nozzle in the ejector, which nozzle directs the vapor from the evaporator to the ejector for incorporation within the vapor stream. The cooling method according to claim 2, wherein 4. The method of claim 1, wherein the pressure of the steam from the evaporator is increased by heating the steam before it is combined with a steam stream. 5. A second working fluid is evaporated and compressed in a second evaporator, condensed in a second condenser, and expanded before being recycled to the second evaporator; vapor of the second working fluid in the first evaporator is used to heat the vapor of the first working fluid in the first evaporator, such that the vapor from the evaporator is heated before the vapor is combined into a vapor stream. 5. The cooling method according to claim 4, wherein the pressure of the steam is increased. 6. said first working fluid vapor from a generator is expanded and formed into a vapor stream by passing the vapor through a nozzle in an ejector, said nozzle evaporating the vapor for incorporation within said vapor stream; The cooling method according to claim 5, wherein the cooling method is caused to be drawn from the container to the ejector. 7. Said first working fluid steam from the turbo-congreser is expanded and formed into a steam stream by passing the steam through a turbo-congressor, in which the steam from the generator is 6. The method of claim 5, wherein the compressor is expanded to provide power for itself, and the compressor forms a vapor stream that combines vapor from the first evaporator.