DE2246654A1 - METHOD AND DEVICE FOR COOLING LIQUID - Google Patents

Description

Method and device for cooling liquid

The invention relates to a method sum evaporation heat exchange, in which the water to be cooled is sprayed in such a way that it triggers a flow of air. mixing, heat exchange and partial evaporation of the water take effect. The invention particularly relates to a method according to which the water is repeated in a series of Steps is sprayed, with fresh air being introduced for the purpose of heat exchange in each individual step.

An evaporative heat exchanger is usually available to a certain extent Load or cooling conditions, which are determined after the device has been used, “These conditions determine according to the volume of the water to be cooled per unit of time, according to the extent or the temperature range during cooling of the water, and according to the absolute and relative temperatures of the air with regard to the temperatures of the air to be cooled Water.

In order to be able to withstand higher loads, conventional cooling towers can be enlarged or, alternatively, or

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In addition, increase the amount of air required for cooling with increasing energy input up to a certain size. at Injector cooling towers (as described in patent application P 21 32 356.8-13) is more adaptable by changes in the pressure of the sprayed water and as a result possible by changing the drive required for the water pumps.

In contrast, it was found according to the invention that with Cooling towers working with injectors are exposed to higher loads without increasing the size of the equipment and without increasing the drive for the water pumps would have to.

In an injector or injection cooling tower, in which the Was-8er itself is used to pump or suck the air, the air and water necessarily flow simultaneously; as a result, the initial temperature differences decrease between air and water when this mixture is passed through the cooling tower as a stream. Since the temperature differer.z has an effect on the efficiency of the system used for heat exchange, systems of this type are subject to the disadvantages of small temperature differences when the desired approach temperature is reached.

According to the invention, this effect of the small temperature difference in injector cooling towers can be reduced, if the water is subjected to a series of individual cooling stages and has the advantage of large initial or inlet differences the temperatures of air and water. Due to the significantly increased heat transfer due to the series connection of water versus air, the size of the required unit can be reduced considerably by one absorb comparable heat load without the pump drive would be increased.

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The invention is explained using an exemplary embodiment with reference to the accompanying drawings.

FIG. 1 is an isometric view of two injection cooling shrouds connected together in accordance with the invention;
and

Figure 2 is a "graph of the size of the injection systems against thermal loads for the purpose of illustrating the advantages of the method according to the invention compared to conventional methods.

In Figure 1 of the drawings, two evaporation cooling towers are included Injection shown. The details of the injection or injector towers according to FIG. 1 are given in patent application P 21 356.8-13 shown and explained. After the units have the same structure, the one on the left in FIG Unit named as the first unit or first stage for the purpose of simplified explanation, while the one on the right Unit is named as the second stage. Reference numbers of the second stage assigned to the same parts have the addition a.

Each unit of the individual stages has an air inlet Io, loa, a throttle 11, 14a and downstream of the throttle one Diffusion or relaxation area 12, 12a. A number of vapor separators are located outside the expansion area 13, 13a and also an air outlet provided with guide bodies 15 »15a 14, l4a. The air outlet directs the exiting air away of the unit directed outwards and upwards.

Water, from which heat is to be extracted, is generated with the help of a pump

16 of a heat load or heat dissipation to the collecting line

17 of the first used for the method according to the invention Level forwarded. The manifold 17 feeds a series of horizontally extending conduits 18 which extend across the mouth

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or the air inlet Io of the unit. Each of the individual lines 18 is provided with nozzles 19, which at a distance are attached along the pipe. The water, whose heat is to be withdrawn, is drawn into the with the help of these nozzles Throttle 11 sprayed. This has the consequence that air is bent inward from the surrounding atmosphere or outside air and is the source of air for the present system. The air and the water mix, with a certain proportion of the water evaporates. The air is discharged through the outlet 14 diverted, while the water collects in a sump 2o. This water is with the help of a pump 22 via a pipe 21 sucked off and pumped into the collecting line 17a of the second unit. The collecting line 17a feeds the lines 18a a, which are each comparable to nozzles 19a in one of the first unit Way are equipped. The heat exchange process the first stage is repeated within the second stage with the difference that the one exiting through the nozzles 19a Heat has already been withdrawn from the water during its passage through the first stage. The air source for the two units is, however, the same, so that from the nozzles 19 and 19a leaking water is exposed to the same air temperature. The water exiting from the second unit collects in a sump 2oa and 'is via a line 23 of the heat absorption fed.

For a better understanding of the mode of operation and the results of the multistage process according to the invention, the following referred to examples.

Example I.

It is assumed that 379 · οοο 1 per minute at a required Tenjperaturreduzierung of water of 51.6 ⁰ C to 36.3 ° C, that is corresponding to a reduction of 15.3 ° C. At the inlet (mouth of Io in accordance with Figure 1) is assume a humidity temperature of 22.2 ⁰ C. A single unit

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The design shown in Figure 1 would have a cross-sectional area of the throttle (reference number 11 in Figure 1) of about 749o m ² and 29oo BHP (brake horsepower = brake PS) with a degree of humidity of 26.3 ° C at the outlet to cope with such heat dissipation (Reference number 14 in Figure 1). Such a unit is very large and comparatively expensive to manufacture and maintain. Instead of such a single unit, the method according to the invention is carried out in stages, whereby the following considerable size reduction is achieved:

First stage

flow

Temperature decrease, throttle area or opening area energy

Air temperature Air temperature

379000 1

51.6 ° C to 36.3 ° C I404 m ²

I45o BHP (brake horsepower

= Brake -PS)

22.2 ⁰ C degree of humidity warmth at Io in Fig.l

Degree of moisture warmth at 14 in Fig.l

32.2 ^° C

Second step

flow

Temperature decrease, throttle area or opening area energy

Air temperature

Air temperature

379000 1

36.3 ° C to 29.4 ° CI, 404 m ²

145o BHP

22.2 ° C moisture warming

27.3 ⁰ C

grad at loa in Fig.l

Degree of moisture warmth at 14a in Fig.l

ty

The throttle area of the first stage of I4o4 m plus the throttle area of the second stage of I4o4 m ² is 2808 m ² . The throttle area of a single heat exchanger unit is less than the sum of the throttle areas of stages 1 and 2: 7491 - 2808 = 4683 m ² , in other words, one by the process and by the pre

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Direction according to the invention achieved size savings of 4683 m ² or 62 %.

It can be seen that the reduction in the required throttle cross section is more than 4645 m ² .

If the two stages are connected in series as shown in Figure 1 of the drawings, the energy is fed into the water at two positions. If half the energy required by a single large unit is entered at each of these locations, the result is the same. The BHP (brake horsepower) is a function of the pressure for any given flow (ltr). As a result, if half the pressure is applied to each of the two positions in series, then the sum will be the same (I45o BHP plus I45o BHP = 2900 BHP). As a result, there is no increase in energy (BHP) in the present example, but there is a saving in the throttle cross-section of 468J3 m, i.e. 62 %.

A second example is given below, using a much smaller water flow to reduce the flow rate the device and the method according to the invention can be achieved To make savings clear:

Example 2 Single unit

Current 379o 1

Temperature decrease 39 "4 ⁰ C to 29.4 ° C

Throttle area or opening area 33.4 m ²

Energy 41.2 BHP

Degree of humidity

at the inlet 25.5 ° C

Degree of humidity

at the outlet 28.2 ° C

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First stage

flow 3790 1 • 3o.8 ° C Temperature decrease 39.4 ° C to 32.7 ° C Throttle area 8.8 m ² 379o 1 energy 2o, 6 BHP 32.7 ° C to 29.4 ° C Degree of humidity 8.8 m ² at the inlet 25.5 ° C 2o, 6 BHP Degree of humidity at the outlet 25.5 ° C Second step flow 28.2 ° C Temperature decrease Throttle area energy Degree of humidity at the inlet Degree of humidity at the outlet

In this embodiment, a saving of 15 ₉ 8 m of the throttle cross-section or the throttle area, or of kl.2 % with the same energy (BHP) was achieved.

In order to further explain the effect of the method and the device according to the invention, reference is therefore made to FIG. 2. In Figure 2, the injector cooling by means of cooling towers is shown both for individual systems and for systems operating in stages; the physical size is shown along the ordinate, while the temperature range is shown on the abscissa. The recording is designed for a constant approach temperature. In order to understand FIG. 2 and the exemplary embodiments mentioned above, it should be pointed out that the expression "temperature range" denotes the area of cooling _{9 to} which the water is to be exposed. To the water from a temperature of 51.6 ° C

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Cooling down to 37.8 ° C is a temperature range ton 13.8 ° C necessary. The term "approach temperature" means the difference between the degree of moisture warmth of the 'a *' entering air (Figure 1, mouths Io and 'loa) opposite the' Temperature of the exiting water (Figure 1) in the swamps 2o and 2oa.

In FIG. 2, the ordinate shows an index of physical size. In the case of injector cooling towers, certain proportions are required; a practical index or value of the size is defined by the throttle cross-section or the throttle area, if a Venturi throttle is used. If water is sprayed into a pipe of uniform cross-section, then the area of this cross-section is a value or an index of the size. T. - Tg means the temperature range mentioned above, ie the difference between the water temperature at the beginning and the water temperature at the end. According to FIG. 1, ^T _A exists at point 16, while T _£ exists in the swamp 2oa.

In FIG. 2, the line labeled "single unit" shows the increase in physical size which is required for single-stage processes in order to achieve higher temperature ranges with the same flow and with the same conditions of approach temperatures. The line "Step procedure ^11" shows the total throttle size of the two units, which are operated in series with water and in parallel with air, assuming the same total energy input or BHP on which the individual unit was based. In this case, the sum of the throttle dimensions significantly smaller than the throttle size required for the individual unit to cope with the same loads or temperature reductions. Since the costs of cooling towers are essentially proportional to the size, a reduction in the throttle cross-section or the constriction area also means a reduction in manufacturing costs Manufacturing costs of 6o % can be achieved, according to Figure 1 and right

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Page of Figure 2 is to be regarded as essential. When injector cooling towers be operated in stages according to the invention at constant input energy, considerable Savings in manufacturing can be achieved.

However, if the drive or the energy input and consequently the operating costs become more important than the original costs of the cooling turner (ie there is less energy input available), the step-by-step method still offers advantages. This concept can be understood if one imagines that the line corresponding to the step process is rotated counterclockwise about its origin, as shown by the arrow in FIG. If the line corresponding to the step progression or step mode is rotated counterclockwise ₉ the energy input decreases.

As a result, through step-by-step operation, the drive or » Significant energy input compared to one of its units be reduced before the corresponding value of structural size of the gradual operation that of the operation with is the same as a single unit.

Although the drawings show two stages to cool the water in series, it is also within the scope of the invention to apply more than two procedural stages or corresponding units in order to meet certain working conditions »

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Claims (13)

September 22, 1972 224665 « Expectations Method for cooling liquid, characterized in that the liquid is in a limited area is sprayed, one end of which is open to a source of Qas, the moisture-warming degree of the gas is deeper than that of the sprayed liquid that the sprayed liquid is a gas flow from the gas source in the direction of the limited area induced to mix the gas with the liquid and around the liquid to partially evaporate that one then separates the gas from the liquid and the liquid at a first Temperature above the moisture degree of warmth of the separated gas collects that you then the liquid in sprayed another limited area, one end of which is open to a gas source, wherein the gas is a Has moisture warmth not higher than that of the gas from the first-mentioned gas source, so that the sprayed liquid flows into a gas stream from the gas source induces the wider limited area to mix the gas with the liquid and partially around the liquid to evaporate, that then the gas and the liquid are separated and that the liquid on a second Temperature above the moisture warmth of the separated gas, but below the first temperature is collected. 2. The method according to claim 1, characterized in that the liquid located at the second temperature continues is sprayed into one or more limited areas, each of which is open to a gas source Has the end, wherein the degree of moisture warmth of the gas is not higher than at the first-mentioned gas source. 3. A method for cooling water, characterized in that that the water is sprayed into a confined area, one end of which faces a source of atmospheric air Is open, with the air having a degree of moisture warmth 3ÜU8U / 03 16 BAD ORIGINAL - Io - which is less than that of the sprayed water, that one induces an air flow from the air source in the direction of the limited area by the spraying of the water in order to mix water and air and to partially evaporate the water, that one then exit the air leaves and collects the remaining water at a first temperature above the moisture degree of warmth of the exiting air, that the remaining water is sprayed into a further limited area ₃ one end of which is also open to the source of atmospheric air, the sprayed water being an air stream from the air source in Direction of the limited area induces to mix water and air and to partially evaporate the water, and that the water is then collected, having a second degree of moisture warmth above the temperature of the exiting air but below the first temperature. 4. The method according to claim 3, characterized in that the water located at the second temperature is then in one or more confined areas is sprayed, each area one against a source of atmospheric air Has opened end, the air having a moisture degree of warmth which is no higher than at the first-mentioned source. 5. The method according to claim 3 »characterized in that the energy of the sprayed water in the first limited area and the energy of the sprayed into the wider limited area Water are equal. 6. The method according to claim 3 _}, characterized in that the first and the further limited area have substantially the same size. 7. Device for cooling water in a multi-stage injector system, characterized in that the device _! ·! _ ■ 3098 U / 0-3-1 6 first (IH) and second (11a> injector cooling units, each of the units having an air line (lo _f 11, 12; loa, Ha ₉ 12a) through which the air can flow, that a liquid spray device (18, 19; 16a, 19a) liquid is sprayed into the air line to induce an existing air flow in the air line that a separating device (13, 13a) is provided downstream of the liquid spraying device in the air line to separate the liquid from the air leaving the air line ^ that below the Separating device a liquid sampler (2o, 2oa) is provided which collects the separated liquid, and that a device (21, 22) transports the liquid from the collecting device of one cooling unit to the liquid spraying device of the other cooling unit. Device according to Claim 7, characterized in that the device transporting the liquid comprises a pump (22) which pushes ^{the liquid under pressure 1} through the liquid spray device of the other cooling unit. 9. Apparatus according to claim 7, characterized in that the cooling unit is arranged to pass through the same Il Air source is applied. 10. Apparatus according to claim 7 »characterized in that the cooling units are essentially the same size and capacity exhibit. I ₁ 11. The device according to claim 7 »characterized in that the cooling units are aligned so that they are acted upon by a common fresh air source and the air drop off in a common area. 12. The device according to claim 7, characterized in that the device has one or more additional injection cooling - 12 - 309814/0316 units has that each additional unit with an air line is provided through which the air sweeps that a liquid spray device liquid into the air line injected to induce a flow of air in this, that a separator within the air line downstream the liquid spray device is arranged to separate liquid from the air exiting the line, that there is a collecting device for liquid below the separating device, which collects the separated liquid and that one device collects the liquid from the liquid collecting device of the two injector cooling units borrowed one or more additional items via a series assignment Cooling units. 13. The apparatus according to claim 12, characterized in that the cooling units are arranged geometrically so that they have a Have common fresh air source, while equipped with a common discharge area for the exiting air 3ÜÜRU / 0 316