HU201141B - Method and apparatus for decreasing the energy consumption of compressor coolers - Google Patents

Abstract

The invention relates, on the one hand, to a method of reducing the energy consumption of cooling equipment having at least one evaporator (E), a compressor (K) in its circuit. a condenser (C) and a liquid collecting tank (G) are carried out in such a way that the refrigerant from the liquid collection vessel (G) is in a liquid state. or in two fluid tanks connected in parallel, the vapor released in the charged fluid reservoir (1) is aspirated with a piston compressor (D) and returned to the condenser (C) and compressor (K) section in the liquid container (1), thereby cooling the refrigerant to the evaporator. cooled to or near the temperature of the cooled refrigerant on the equilibration vessel (5) and / or the known liquid separator tank and / or the metering valve (A) before the evaporator (E). In another aspect, the present invention provides an apparatus for reducing energy consumption in cooling installations, preferably a method according to claim 1, wherein at least one (E), compressor (K), condenser (C), and fluid collection tank (G) is provided in a cooling stream thereof in such a manner that at least one (or two parallel) fluid reservoirs (1) having a fluid space (1b) and a vapor space. Figure 7 -1-

Description

In another aspect, the invention provides apparatus for reducing energy consumption in refrigeration equipment, preferably for the process of claim 1, wherein the refrigeration circuit comprises at least one (E), a compressor (K), a condenser (C), and a fluid collection vessel (G). at least one (or two parallel connected) liquid containers (1) having a liquid space (lb) and a vapor space

The scope of the description is 16 pages. Figure 7

EN 201141 Β (la) and the steam compartment (la) on the suction nozzle of a piston compressor (D) and the discharge nozzle of the piston compressor (D) in the section of the refrigerant circuit between the condenser (C) and the compressor (K), ), is connected to the refrigeration circuit in front of the evaporator (E) via an equalization vessel (5) and / or a fluid separator vessel and / or a metering valve (A). (Figure 1)

-2HU 201141 Β

The present invention relates to a method and apparatus for compressor refrigeration equipment. By applying the invention, the energy consumption of the cooling circuits comprising at least one compressor, a condenser, a liquid collection tank and an evaporator can be reduced.

As is known in the art, compressor refrigeration equipment used today generally utilizes vapor refrigerant. The refrigerant is able to absorb heat without evaporation by evaporation and condensation without heat change. The boiling point or evaporation temperature of a given medium depends only on the pressure. By reducing the pressure, the boiling (saturation) temperature is reduced. In refrigerators, this rule is used to cool the refrigerant fluid to the heat of evaporation (evaporation) temperature.

Depending on the degree of cooling desired, compressor refrigeration units have evolved over time. We can get a good overview of these, for example. József Villányi: A Practical Guide to Refrigerators (Technical Publisher, 1963, Budapest).

Whatever the design of the known refrigeration equipment, they have in common that the liquid refrigerant at a temperature above the evaporation temperature cools to the evaporation temperature through the throttle without loss of enthalpy. This process causes loss of energy.

It is therefore an object of the present invention to provide a method and apparatus for significantly reducing the aforementioned energy loss. The present invention is based on the discovery that, when the refrigerant leaving the condenser and its associated fluid collection tank is introduced into another, preferably lying, container, the refrigerant fluid, that the vapors generated during the compressor suction stroke are conveyed to the condenser at the compressor stroke or after reaching a suction pressure lower than the intermediate pressure in a two-stage refrigeration unit, to the pressure line of the lower stage compressor. This way of cooling the liquid requires less energy than is necessary for the original choke process,

The invention thus provides a method for reducing energy consumption in refrigeration equipment having a refrigerant circuit comprising at least one evaporator, a compressor, a condenser and a liquid collection vessel, the process being performed by liquidating the refrigerant from the collection vessel in a liquid state parallel to each other. venting the vapor released in the charged fluid reservoir with a piston compressor and returning it to the section between the condenser and the compressor, thereby cooling the refrigerant to or near the evaporation temperature, and then cooling the refrigerant in the equalization tank and / or or through a metering valve to the refrigerant circuit before the evaporator.

In a preferred embodiment of the process according to the invention, the liquid refrigerant is introduced alternately into two parallel-connected tanks, and while steam is drawn from one of the liquid tanks, the cooled refrigerant is introduced into the refrigerant circuit from the other.

The invention also provides an apparatus for reducing energy consumption in refrigeration equipment, preferably

The method of claim 1, wherein the refrigerant circuit comprises at least one evaporator, compressor, condenser and fluid collection vessel, and is configured to have at least one or two fluidly connected fluid containers having a liquid space and a vapor space, and a vapor space on the suction nozzle of a piston compressor, and the discharge nozzle of the piston compressor in the section of the cooling circuit between the condenser and the compressor, and the fluid space is connected through a balancing tank and / or liquid separating tank and / or metering valve.

In a preferred embodiment of the apparatus according to the invention, the liquid container is in a lying position.

In another preferred embodiment of the apparatus according to the invention, the piston compressor suction nozzle is connected to a section of the refrigerant circuit between the compressor and the evaporator through a by-pass with a non-return valve.

A third preferred embodiment of the apparatus according to the invention is that an inlet closure is provided in the conduit for supplying the liquid space of the liquid reservoir and an outlet closure is provided in the conduit for discharging the liquid space.

A fourth preferred embodiment of the apparatus according to the invention is one in which a vapor drain closure is inserted between the vapor space of the liquid container and the suction nozzle of the piston compressor.

In a fifth preferred embodiment of the apparatus according to the invention, the fluid reservoir is connected to the cooling circuit through a balancing tank and a metering valve.

A sixth preferred embodiment of the device according to the invention is that a pump is inserted in a bypass branch between the balancing tank and the metering valve.

A seventh preferred embodiment of the apparatus according to the invention is one in which the fluid space of the fluid reservoir is connected to a fluid separating vessel via a drain closure or dispensing valve.

Finally, a preferred embodiment of the device according to the invention is one in which the discharge port of the piston compressor is connected to the condenser via a half-closing non-return valve and, secondly, to an output of the lower stage compressor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in more detail by reference to the accompanying drawings, in which: Fig. 1 is a schematic diagram of the simplest arrangement of the apparatus according to the invention; Figure 2 / a is a diagram of the cooling circuit,

HU 201141 Β a 3-7. Figures 3 to 5 show some variations of the apparatus according to the invention.

The apparatus schematically shown in Figure 1 is a simple single stage refrigeration unit, in which a circuit consisting of a condenser C, a fluid collection vessel G, an evaporator E and a compressor K is supplemented with a liquid container 1, an expansion vessel 5 and a metering valve A.

The vapor space 1 / a of the liquid container 1 is connected to a suction nozzle of a piston compressor via a vapor discharge closure 2 and the discharge port of a piston compressor D to a pressure line in the cooling circuit between the compressor K and the condenser C.

The liquid space I / b of the liquid reservoir 1 is connected via an inlet closure 3 to the liquid collection reservoir G and through an outlet closure 4 to the equalization reservoir 5.

Fig. 1 shows further assemblies, the function of which will be described after describing the process.

The state changes of the refrigerant circulating in the apparatus are shown in the diagram lg p-h in Fig. 1 / a. The refrigerant undergoes the following state change during the process:

After opening the inlet closure 3, the liquid container 1 is filled and the inlet closure 3 is then closed. Meanwhile, the steam drain closure 2 and the drain closure 4 are closed. The vapor drain plug 2 is then opened and, under the suction action of the piston compressor D, the pressure in the tank 1 is reduced from the initial p to p ₀ . The refrigerant fluid status indicators are read in sections III - IIP of the lower limit curve according to the instantaneous suction pressure ps. The compression work of the exhaust vapor with varying suction pressure p> can be calculated as shown in Fig. 1 / a.

In fact, the piston compressor D expands the refrigerant enclosed in the liquid container 1 from p to p ₀ . however, due to the large number of vapor portions (corresponding to the displacement volume), the differential pressure change can be replaced by a throttle. If we consider isentropic pressure reduction on the lower boundary curve, we would obtain a slightly more favorable result.

Let the initial amount of refrigerant in the container 1 be 1 kg. Theoretical compression energy requirement for cooling 1 kg of refrigerant initially to ΙΠ to IIP:

n

Σ W = Σ mr, · xí · Wi (kJ) i = l

Realistically, if the indicated efficiency is a function of the pressure ratio:

η; _π = 1 - 0.04 -

Pi η 1

Σ Wind = Σ - mr, · x, · Wj (kJ) i = l ηίη

Refrigerant remaining at p ₀ (temperature t ₀ ):

n mf = 1 - Σ mn · xí (kg) i = l

Theoretical power requirement of compressor K with cooling capacity q ₀ :

Wk = mf W _n = mf (hu - w) (kJ)

Real Energy Requirements:

W _k

W _ki = - (kJ) η in

K compressor cooling capacity:

qo = mf · r ₀

Theoretical specific cooling capacity:

qo ε = mf · W _n + ε W

The indicated qo _{£ i} -. Mf · W _n + S Wind

Let the chiller be characterized by:

refrigerant: R 717 (ammonia) condensation temperature: t = 35 ° C evaporation temperature: t ₀ = - 15 ° C

The specific calculation gives the following result: W = 18.88 kJ

Wind = 21.84 kJ

Wk = 212.74 kJ

Wki = 276.28 kJ ε = 4.69

8i = 3.65

Figure 2 is a diagram of a commonly used (prior art) refrigeration unit. This differs from the conventional design by the fact that there is a fluid separation tank L between the throttle valve F and the evaporator E to which a suction nozzle of a piston compressor D is connected. The energy requirement for cooling the liquid can thus be calculated separately. The discharge port of the reciprocating compressor D is connected to the discharge line of the refrigerant circuit between compressor K and capacitor C. Thus, the vapor produced by the throttling is compressed by a piston compressor D independent of compressor K. The state changes of the refrigerant are shown in the lg p - h diagram in Fig. 2 / a.

Based on Figure 2 / a and with the characteristics of the refrigeration unit specified above, the following values are obtained:

HU 201141 Β mf = 0.824 kg m _g = 0.176 kg

W _k = 256.62 kJ Wki = 333.27 kJ f = 4.21 fi = 3.24

Comparing the results obtained for the two types of chillers, the following can be determined.

According to the invention, the energy requirement for cooling the refrigerant is theoretically:

ZW = 18.88 kJ with conventional equipment, theoretically: m _g Wk = 0.176 · 256.62 = 45.165 kJ

The ratio of the two values is:

ZW 18.88

- = - = 0.418 (41.8%) m _g Wk 45.165

Energy demand in reality: according to the invention

ZWind = 21.84 kJ with conventional equipment:

1

- · m _g · W _k = - · 45.165 = 58.66 kJ ηϊη 0.77

The ratio of the two values is:

ZWind 21.84

- - = - = 0.372 (37.2%)

58.66

- · m _g Wk ηΐη

Thus, the process according to the invention requires only 37.2% of the energy required for conventional refrigeration to cool the refrigerant between 35 and 15 ° C.

Energy savings for the whole circuit:

ε - ef 4.69-4.21

Δε = - 100 --- 100 = 11.4%

E 4.21

In reality:

εί - εη 3.65 - 3.24

Δει = - 100 = - 100 = 12.65% εη 3.24

The percentage of energy savings in total energy consumption is also very high.

The dotted line in Figure 1 is essential for the practice of the invention, but additional fittings are required for actual implementation.

Safe operation of the cooling circuit requires that the fluid level of each fluid storage element is at least minimally guaranteed. Therefore, the liquid collection vessel G is provided with a liquid level indicator 13, and the equalization tank 5 is provided with a liquid level indicator 14. The liquid level indicators 13 and 14 are configured to detect only a minimal level of liquid and are also useful for influencing instantaneous fluid flow.

For reasons of technology, both the maximum and the minimum of the liquid level must be limited at the liquid container 1. Therefore, the liquid level sensor 10 is coupled to a lower liquid level indicator 11 and an upper liquid level indicator 12 as well. It is also important to sense the pressure conditions that occur during the process. Therefore, a Ni pressure switch is arranged between the common point of the liquid container 1 and the steam drain closure 2 and the inlet of the condenser C, and a Ni pressure switch between said common point and the inlet of the compressor K.

The common point of the evaporator N and the compressor K is connected via a non-return valve 6 to the intake manifold of the piston compressor D. The non-return valve 6 is mounted so that it opens towards the reciprocating compressor D.

Between the balancing tank 5 and the dispensing valve A, a valve 9 is mounted, in parallel with a ski pump and a bypass branch with a bypass valve 7.

The process of the present invention, the energy relations of which have been described above, is accomplished by the apparatus described as follows:

The liquid refrigerant exiting the fluid collector G is introduced into the liquid container 1 by opening the inlet closure 3. When the liquid level in the liquid container 1 reaches the upper level, the transducer 12 of the liquid level indicator 10 instructs to close the inlet closure 3. The upper level of the liquid level must be set in such a way that no liquid can be drawn through the vapor drain plug 2.

In the filled liquid container 1, the liquid refrigerant evaporates. The vapor generated is introduced from the vapor chamber la through the vapor barrier opening 2 which has been opened in the meantime to the piston compressor.

The D piston compressor runs continuously. The steam outlet closure 2 is opened by the pressure switch Ni due to the difference between the compression pressure p _{and the} suction pressure p _s .

The continuous operation of the piston compressor D is made possible by being connected in parallel with the compressor K via the non-return valve 6. Otherwise, the device would be functional without this parallel connection. In this case, it should be ensured that the piston compressor D is started simultaneously with the opening of the steam outlet 2.

As the piston compressor D draws steam from the liquid container 1, the liquid refrigerant remaining in the liquid container 1 cools. Steam extraction is continued until the refrigerant is cooled to or near the evaporation temperature. The closer we get to the evaporation temperature, the more energy savings can be achieved.

When the cooling of the liquid refrigerant in the liquid container 1 is completed, the difference between _s suction pressure p _s and po

-5UK 20114! Switch Β instructs to close the steam drain closure 2 and open the drain closure 4. The cooled liquid refrigerant flows through the drain closure 4 into the equalization tank 5 and from there through the metering valve A to the evaporator E. so it is returned to the normal cooling stream.

When the liquid container 1 is empty, the transducer 11 of the fluid level indicator 10 instructs to close the drain closure 4 and to open the inlet closure 3. This will restart the process of the invention.

If the design of the chiller is such that it is difficult for the refrigerant to reach the evaporator E from the expansion tank 5, the Si pump may be incorporated into the system. The bypass valve 7 can be used to change the delivery capacity of the Ski pump.

The cooling circuit shown in Fig. 3 is an example of the possibility of connecting a forced-circulation (pump) chiller to the apparatus of the present invention.

In the apparatus of the present invention consisting of a liquid container 1 having a vapor space la and a liquid space lb, a steam outlet closure 2, an inlet closure 3 and a reciprocating compressor D, the liquid circulation function L liquid separator tank 15 liquid level sensor 16 is limited to 17 liquid level indicator using AVL equalizing volume and cooled between the volume of the cooled liquid tank 1 V _l = V av relationship must exist.

Liquid dosing in the liquid separator tank L is performed intermittently such that when the liquid in it is reduced to a minimum level, the liquid level indicator 17 of the liquid level sensor 15 instructs to open the drain closure 4. When the liquid space 1b of the liquid container 1 has been emptied, the liquid level indicator 11 of the liquid level sensor 10 instructs to close the drain closure 4 and to open the inlet closure 3. From here, the process continues in the familiar way.

The liquid level indicator 16 of the liquid level sensor 15 intervenes in the filling process of the liquid separator tank L only and instructs it to close the drain closure 4 when the liquid level of the liquid separator tank L exceeds the maximum level.

It should be noted here that the elements (pressure switches, fluid level indicators, measuring points, etc.) that are obviously required for the construction of the equipment are not shown in Figure 3 and will not be shown in the following figures, since their application is obvious to those skilled in the art. are not necessary for further understanding of the invention.

Figure 4 shows a schematic of a two-stage refrigerator. The lower stage of the cooling circuit consists of the Ki compressors and the upper stage of the Ku compressors. The arrangement is such that useful cooling is only in the lower stage. The intercooler H is connected in a known manner between the Ki and Ku compressors. the fluid level of which is controlled by the FM level control valve.

Because of these two stages, a non-return valve 19 must be inserted between the discharge port of the piston compressor and the condenser C, and an automatic closure 18 between the discharge port and the compressor Ki. Their task is to ensure the orderly functioning of the conventional cooling circuit.

The elements according to the invention are incorporated in the same manner and the process is the same as described above. The method is further completed by opening the automatic closure 18 when the pressure of the liquid container 1 drops below the intermediate pressure pi.

Figure 5 is a schematic diagram of an apparatus designed to further develop the above two-stage refrigeration unit.

In order to carry out the process according to the invention, liquid tanks 1 and 21 are arranged in parallel. The vapor space la of the liquid reservoir 1 is connected to the piston compressor D via the vapor discharge closure 2 and the vapor space 21 of the liquid reservoir 21 through the vapor outlet closure 22.

Liquid space lb of the liquid container 1, respectively. the liquid space 21b of the fluid reservoir 21 is shown in FIGS. through the inlet closure 23 to the fluid collection container G, the 4 and 4 respectively. through the 24 drain closures the FM? is connected to a level control valve. The fluid level of the intercooler H is controlled by the level control valve FMi.

The process of the invention may be carried out alternately with the liquid reservoirs 1 and 21 so that while the vapor is withdrawn from one of the reservoirs, the cooled liquid refrigerant can be drained off and the liquid reservoir refilled. Due to the alternating operation of the liquid tanks 1 and 21, there is no need for an equalization tank connected to them.

It is also possible to incorporate the apparatus according to the invention in the two-stage circuit so that both the lower and upper stages are cooled. A diagram of such a refrigerator is shown in Figure 6.

The liquid space 1b of the lower stage fluid reservoir 1 is connected via the inlet closure 3, and the liquid space 25b of the upper stage fluid reservoir 25 is connected to the fluid collection reservoir G.

Similarly, the condenser C is connected to the piston compressor D1 for suction of steam generated in the liquid container 1 through the non-return valve 19 and the piston compressor Dn for the suction of steam generated in the liquid container 25.

The fluid reservoir (1) is connected to the metering valve (Ai) through the drain closure (4) and the expansion vessel (5) and to the suction port (Di) of the piston compressor (2) via the vapor vent closure (2).

Similarly, the fluid reservoir 25 is connected via the vapor drain closure 26 to the suction port of the piston compressor Dh and through the vent closure 28 and expansion vessel 29 to the upper stage metering valve An and the level control valve Fm.

The piston compressor Di is connected to the compressor Ki through a non-return valve 6, and the piston compressor Dn is connected in parallel with the compressor Ku through a non-return valve 20.

HU 201141 Β

The operation of both the liquid reservoirs 1 and 25 is the same as described above, so that no further description is required.

The two-stage chiller can also be constructed as shown in Fig. 7 so that the lower stage operates only on the intermediate chiller H of the upper stage. Here, the lower stage fluid reservoir 1 is filled from the upper stage balancing tank 29, and the pressure port of the piston compressor Di, together with the pressure line of the compressor Ki, is connected to the intercooler H. The cooling system operates as it has been known so far, so no further description is required.

Claims (11)

PATENT CLAIMS A method for reducing energy consumption in refrigeration units having at least one evaporator (E), a compressor (K), a condenser (C), and a fluid collection vessel (G) in a cycle, characterized in that the refrigerant is discharged from the fluid collection vessel (1). G) in a liquid state is introduced into one or two parallel fluid tanks (1, 21, 25), the vapor released in the filled liquid tank (1, 21, 25) is sucked out by a piston compressor (D) and recycled to the condenser (C) and K), the coolant being cooled to or near the evaporation temperature in the fluid reservoir (1, 21, 25), and then the cooled coolant in an equalization reservoir (5, 29) and / or in a liquid separator (L) and / or metering valve known per se (A) is introduced into the cooling circuit before the evaporator (E). Method according to Claim 1, characterized in that the liquid refrigerant is introduced alternately into the two parallel-connected tanks (1,21), and while the vapor is withdrawn from one of the liquid tanks, the cooled refrigerant is introduced from the other. refrigeration cycle. Apparatus for reducing energy consumption in refrigeration equipment, preferably for the process of claim 1, comprising at least one evaporator (E), a compressor (K), a condenser (C) and a fluid collection vessel (G) in the refrigeration circuit. at least one or two fluid tanks (1, 21, 25b) having a fluid compartment (1b, 21b, 25b) and a vapor compartment (1a, 21a, 25a) and the steam compartment (1a, 21a, 25a) and a piston compressor (1); D) the suction nozzle and the piston compressor (D) the discharge nozzle in the section of the refrigerant circuit between the condenser (C) and the compressor (K), while the fluid space (lb, 21b, 25b) on an equalization tank (5, 29) j and / or is connected to the refrigerant circuit through the liquid separator tank (L) and / or the metering valve (A) before the evaporator (E). Apparatus according to claim 3, characterized in that the liquid container (1, 21, 25) is in a lying position. 0 Apparatus according to claim 3 or 4, characterized in that the suction nozzle of the reciprocating compressor (D) is connected via a by-pass with a one-way non-return valve (6) to the refrigerant circuit, the compressor (K) 5 and the evaporator (E). ). 6. Apparatus according to any one of claims 1 to 6, characterized in that a fluid closure (3, 23, 27) is provided in the conduit for supplying the liquid space (1b, 21b, 25b) of the liquid container (1, 21, 25b), A drain closure (4, 24, 28) is provided in the discharge line 20 (1b, 21b, 25b). 7. Apparatus according to any one of claims 1 to 4, characterized in that a vapor discharge closure (2, 22, 26) is inserted between the vapor space (1a, 21a, 25a) of the liquid container (1, 21a, 25a) and the suction port of the piston compressor (D). 8. Referring to FIGS. Apparatus according to any one of claims 1 to 5, characterized in that the fluid reservoir (1, 25) is connected to the cooling circuit through a balancing vessel (5, 29) and a metering valve (A1, An). 9. a 3-7. Apparatus according to any one of claims 1 to 3, characterized in that in a by-pass branch between the balancing tank (5) and the metering valve (A) 35 one pump (Ski) is connected. 10. Apparatus according to any one of claims 1 to 3, characterized in that the liquid space (1b) of the liquid container (1) is a liquid separator through a drain closure (4) or a metering valve. It is connected to 40 tanks (L). 11. A 3-10. Apparatus according to any one of claims 1 to 4, characterized in that the discharge port of the piston compressor (D) is on one side closed to the condenser via a non-return valve (19) 45 (C) connected, on the other hand, is connected to the output of the lower stage compressor (Off) through an automatic closing element (18).