DE19605241A1 - Cooling system - Google Patents

Abstract

The cooling system has a heat exchanger through which passes a working medium, a liquid, made up of one or more substances and an expansion valve through which the medium passes into a separator. The separator divides the medium into a stream of vapour which passes into a Ranque and Hilsch vortex tube after passing through the heat exchanger, and a stream of boiling liquid . In the vortex tube the vapour flow is divided into a warm flow and a cold flow the hot flow passing through a cooler and then flowing through a return line and a control valve which mixes it with the cold flow. In the resulting wet vapour the liquid component is greater than it would be if directly pressure relieved in an adiabatic valve.

Description

The invention relates to a cooling system in which a flow of working fluid exothermic relaxation process is subjected.

Chillers and heat pumps are generally known those with compression, absorption or adsorption work technology. With these chillers or heat will pump relaxation elements such as chokes or Relief valves used. This is necessary to the temperature of one usually as a liquid  lying working material (also as work equipment records) under a certain, generally by the Lower the environment to a predetermined level.

Details of the known processes are shown in the following the basic literature explained in detail:

• - R. Plank, refrigeration manual, Springer, Berlin, 1936 ff.
• - H.L. von Cube, ed., Textbook of refrigeration technology, 2 vols, C.F. Müller, Karlsruhe, 1981.
• - Bäckström, Emblik, refrigeration technology, Verlag G. Braun, Karlsruhe, 3rd edition, 1974.
• - H.L. by Cube, F. Steimle, heat pumps VDI publishing house, Düsseldorf, 1978.
• - W. Niebergall, sorption chillers, manual der Kältetechnik, R. Plank (ed.), Vol. 7 Springer, Berlin, 1959.
• - G. Alefeld, R. Radermacher, Heat Conversion Systems, CRC Press, Boca Raton etc., 1994.

This state of the art is also referred to visibly all terms not explained here expressly referenced.

The relaxation process of the working fluid in the throttle runs adiabatically, isenthalpically and with loss of exer gie or with the production of entropy. The work fluid evaporates partially, so it is after Ent voltage in the cooled state is no longer complete, but only partially as a liquid for cold generation or for heat absorption available.

This is one of the main causes for that the performance figures of the chiller or Heat pump processes are generally much smaller than their theoretically maximum possible through the car values described are emergency barriers. For reduction  advantageous to pre-cool the working fluid. This is but generally only very limited, or without additional effort only up to the ambient temperature possible.

The invention is based on the task, the Lei performance figures of chillers and heat pumps to increase the relaxation process of the fluid Work equipment is further developed in the throttle that the liquid fraction ver after relaxation increases, the proportion of steam decreases, d. H. the enthalpy pie of the working fluid compared to its value in Entry condition before the throttle is reduced and thus the exergy losses during relaxation are reduced the.

An inventive solution to this problem is in Claim 1 specified. Advantageous training appendices are the subject of claims 2 to 6. The An sayings 7 and 8 relate to advantageous uses the system designed according to the invention.

According to the invention there is a thermal separation effect in a further developed vortex tube according to Ranque and Hilsch uses: This is a compressed, flui the, d. H. especially a liquid, a liquid vaporous or a vaporous working medium current with ambient temperature using the Ranque and Hilsch thermal separation effect exothermic, d. H. releasing heat to the environment, ent tense and cooled.

According to the invention, a Ranque and Hilsch through a separate hot-current cooler and  According to the invention, a Ranque and Hilsch through a separate hot-current cooler and Warm current feedback supplemented with regulating valve and with other procedural elements, namely Wär exchanger, expansion valve, separator and regulator valves, provided such that in the invention Plant a usually liquid, one or more Material-containing flow of working fluid, which kompri lubricated and at ambient temperature, exothermic, d. H. releasing heat to the environment, who relaxes that can, so that in the resulting wet steam the liquid is greater than with direct relaxation in an adiabatic choke.

In the case of heat pump systems, the heat given off can increase at least partially used as useful heat. At Refrigeration systems is reduced by reducing the steam content of the relaxed working fluid the cooling capacity of the Process enlarged.

The thermal separation effect during expansion compressed gases and vapors in vortex tubes Ranque and Hilsch has been in and of itself for many years known. With this effect, a vapor or gas flow under pressure drop into a warm gas flow and a Cold gas flow divided, the temperatures of each over or below the temperature of the input current. The following basic literature is pointed out:

• - G.J. Ranclue, "Experiences sur la detende gira toire avec production simultaneous d′un echappe ment d'air chaud and dlun echappement d′air froid ", Journal de physique et le radium, 4 (1933), No.7;  
• - R. Hilsch, "The expansion of gases in the centri fugal field as a cold process ", Z.f. Naturfor Schung, 1 (1946), 208-214.

An interesting technical application for cooling or Drying moist gases such as B. moist air is in

• - R.v. Linden, device for cooling a compressed gas stream, DE-PS 9 26 729

described.

This effect basically occurs in liquids also on, but is usually so small that it is practical has no meaning. If you want to cool the effect liquid flow or liquid use containing fluid stream must first be pure Working steam can be generated. This can be done by partial Expand and evaporate the fluid to be expanded happen, which is believed to be next ambient temperature.

The invention allows any fluid and kompri lubricated working materials in energy and process engineering exothermic, d. H. to relax while giving off heat. In order to is it z. B. possible, additional in heat pump processes gain heat or, in the case of cold processes, the Cooling capacity of the working fluid around the dispensed Increase heat. Both effects lead to increases the energetic performance figures of the processes that typically 5%, in special cases, approximately Cyclic processes with carbon dioxide (CO₂) as working tel, but can also be 10% -15% (see J.U. Keller, KI Climate, Cold, Heating, 21 (1993), 300-304.)  

The invention is hereinafter without limitation general inventive concept based on execution examples with reference to the drawing exempla risch described on the rest of the Revelation of all not explained in the text explicitly referenced details becomes. Show it:

Fig. 1 is a flow diagram of a thermal reactor system,

Fig. 2 is a flow diagram of the thermal reactor system of FIG. 1 with process data,

Figure 3 (p, h). A refrigerant diagram of the thermal restriction process,

Fig. 4 is an enthalpy current / temperature diagram of the thermal throttling process (H = hin, T).

Fig. 5 is a diagram of the cold thermal restriction process with R22 as working fluid,

Fig. 6 shows a longitudinal section through a cooling vortex tube,

Fig. 7 is a flow diagram of a thermal reactor with additional evaporation, and

Fig. 8 and 9, the circuit of a Ver executed paging system,

Fig. 1 shows a flow diagram of a thermal throttle system constructed according to the invention. The reference symbols used have the following meaning:

WT heat exchanger
D expansion valve or throttle
S phase separator
RV1, RV2, RV3 regulating valves
KWR cooling vortex tube
WK hot current cooler
WR hot current feedback
Working fluid flow (kg / s)
_D steam flow (kg / s)
_L mass flow of boiling liquids (kg, s)
(L, V) wet steam flow (kg / s)
heat output (watts)
Enthalpy current

With regard to the interconnection of the individual elements, reference is expressly made to the illustration in FIG. 1.

The working fluid flow is via the heat exchanger WT passed into the throttle D. The one in relaxing in the throttle D generated steam is always colder than the fluid supplied, i.e. H. the original liquid speed. Would the steam ent directly in a vortex tube spans, the temperature of the hot gas flow would only be un significantly above the temperature of the original river liquid flow, e.g. B. Ambient temperature! That's why the working steam in the vortex tube could be practically none Give off heat to the environment.

According to the invention, therefore, the steam flow _D separated from the residual liquid in the separator S is warmed as far as possible by the heat of the flowing liquid flow in a suitably designed heat exchanger WT, ie to a few degrees below ambient temperature! If the preheated steam flow is expanded in the cooling vortex tube KWR, the temperature of the warm gas stream _H forming near the wall of the vortex tube is, according to experience, clearly, ie about 30-40 ° C. above the ambient temperature. The hot gas stream can thus be cooled in a separate cooler WK, usually designed as a coil. The heat is via cooling fins of the Warmstromküh lers WK to a cooling medium, eg. B. water, or released into the ambient air. After cooling, the hot gas stream _H is reunited with the cold stream _{c also} generated in the vortex tube through the hot stream return with regulating valve RV2 in order to be combined with the liquid stream _L relaxed in a further regulating valve RV3 to form the wet steam stream (L, V).

Fig. 2 shows the system shown in Fig. 1, with process data being entered as an example at positions 3 to 9 .

The data given relate from top to bottom - as can also be seen from the box in FIG. 2 - in each case on the temperature, the pressure, the mass flow, the specific enthalpy and the vapor content of the working agent in the individual states.

The work equipment has when leaving the system a steam content of approx. 28% (mass fractions).

In the case of isenthalperic relaxation in a throttle of a conventional type, the steam content would be approximately 31-32%, as can be seen in FIG. 5. This figure shows the cold diagram of a realized thermal throttling process with the refrigerant R22. The status numbers refer to the states or digits shown in Fig. 2-4.

The enthalpy flow H of the fluid is in the system from  = 1500 W by giving up the heat output = 60 W.  - = 1440 W reduced.

Process data are given for the following places:
3 * state of entry of the working fluid,
4 outlet state of the fluid after cooling in the heat exchanger WT,
5 outlet state of the working fluid after throttle D,
5 ′ state of the boiling liquid in separator D,
5 ′ ′ state of saturated steam in the separator,
6 '' state of the working steam after heating or overheating in the heat exchanger WT,
7 state of the working steam after expansion and cooling in the cooling vortex tube,
8 state of relaxation of the boiling liquid after throttling to the final pressure,
9 Condition of the wet steam after combining the cool working steam ( 7 ) and the relaxed working liquid ( 8 ).

The process values specified are as follows against:

Working substance: R22,
Mass flow (L): 12 g / s,
Heat output: 60 W.

Also expressly referred to the values in FIG. 2 as a disclosure of the invention.

Fig. 7 shows an advantageous development of Ther modrossel. The flow diagram of a thermal throttling system with additional cooling of the hot current emerging from the hot air cooler WK is shown in the separator / evaporator (S, V) of the system. The original circuit according to FIG. 1 is also entered in broken lines.

The difference to the flow picture shown in Fig. 1 is that the hot gas stream _{H is} not directly combined with the cold stream _c after exiting the hot stream cooler WK. Rather, it only follows after the hot gas flow has passed a heat exchanger built into the separator S. There, the hot current _H gives off heat to the partially relaxed and pre-cooled liquid working fluid, which, since it was in a vapor-liquid equilibrium, did not heat up but also evaporated. As a result, the steam flow _{D is increased} compared to that of the circuit shown in FIG. 1. This also increases the warm gas flow _H and the heat ∼ _H emitted by it in the heat exchanger WK!
This circuit, in which the separator S acts at the same time as an evaporator (V), is particularly suitable for fluids and relaxation processes that occur in the vicinity of their critical state, that is to say at low values of the enthalpy of vaporization, such as, for. B. in carbon dioxide (CO₂), since then the increase in steam flow _D can be particularly large by the additional evaporation in the separator / evaporator.

In FIGS. 3 and 4 takes place in the thermal reactor of FIG. 1 exothermic relaxation process of the working medium fluid adopted is program in the Kältedia by Cv Linde (p, h, or ln (p / p₀), h) and in-enthalpy temperature -Diagram shown according to Linhoff (T, = h). The status numbers refer to the digits indicated in FIG. 2.

The boiling and dew lines of the working fluid are highlighted in bold in FIG. 3. The dashed lines indicate the heat exchanger WT of the system. In Fig. 4 are qualitatively the thermal separation that initially takes place in the cooling vortex tube, described by the hot steam state H and the cold steam state C (see also FIG. 6), and the heat output Q given off by cooling the hot steam in the hot steam cooler WK to the environment registered.

Fig. 6 shows a longitudinal section through a cooling vortex tube (KWR), (see also published application DE 43 45 137 A1 from June 29, 1995).

The cooling vortex tube is a vortex tube according to Ranque and Hilsch (RHWR), which is equipped with a hot-flow cooler (WK) provided with cooling fins ( 10 ), a hot-current return line (WR) and a regulating valve RV2. The vaporous working fluid enters through a letting channel ( 11 ) tangentially to the circular cross section of the vortex tube and is separated into a warm flow ( 12 ), state (H) and a cold flow ( 13 ), state (C), forming a swirl flow . The hot current ( 12 ) is cooled in the hot current cooler (WK) and gives off the heat output to a cooling medium or to the environment. Thereafter, the cooled hot stream is recombined with the cold stream 13 via a hot stream recirculation WR and a regulating valve RV2 and emerges as cooled steam or wet steam from the cooling vortex tube.

Fig. 8 shows the flowchart of a ge planned, designed and built thermal throttle system at the Institute for Fluid and Thermodynamics of the University of Siegen. As an experimental system, it is equipped with numerous measuring devices and can be operated, for example, on a refrigeration system with the refrigerant R22. In Fig. 8, the entire system is shown with the supply and discharge lines of the working fluid located in the center on the right in the picture. The usual symbols for the individual components are used, so that a complete description is dispensed with and reference is instead made to the illustration in FIG. 8.

Fig. 9 shows a section of the plant shown in FIG. 8, namely the connection of the cooling vortex tube KWR, the hot-flow cooler WK and the regulating valve RV2.

Above, the invention is based on execution examples without limitation of general inven has been described. Within this general inventive concept can due to above description from a specialist thermal chokes, d. H. Cooling systems without moving parts to exo thermal baths, d. H. heat-releasing relaxation compressed fluid working materials in energy and process engineering nik can be realized.

The system generally consists of a heat rope shear, a relief valve, a separator and a cooling vortex tube, d. H. one by a separate warm current cooler and a warm current return with Regulating valve supplemented vortex tube in particular Ranque and Hilsch. These elements are so together interconnected that a particular with surrounding temp ratur incoming stream of a compressed fluid, d. H. liquid, liquid vapor or mixed vaporous working medium exothermic, d. H. under heat Surrender to its surroundings, forming a river liquid-vapor mixture or a vapor relaxes becomes. The working medium can be a pure substance or a Be a mixture of substances.

The thermal choke can basically be used in all Pro instead of energy and process engineering Ordinary, adiabatic throttle or Ent voltage valves are used. For heat pumps and Refrigeration cycle processes leads to energy savings gen, d. H. to not inconsiderable increases in lei numbers.

Claims (12)

1. Cooling system, in which a flow of working fluid () is subjected to an exothermic relaxation process, that is to say with a heat output () transferred into a wet steam stream ((L, V)), with

• - a heat exchanger (WT) into which a working fluid flow (), which is generally liquid and contains one or more substances, enters,
• - a throttle (D) into which the flow of working fluid emerging from the heat exchanger enters,
• a separator (S) connected downstream of the throttle, which separates the flow of working medium into a vapor stream ( _D ) and a stream ( _L ) of boiling liquid,
• - A vortex tube (KWR), in particular according to Ranque and Hilsch, into which the steam flow occurs after passing through the heat exchanger (WT) and which divides the steam flow into a warm flow ( 12 ) and a cold flow ( 13 ),
• - a warm current cooler (WK), and
• - A warm current recirculation (WR) with regulating valve (RV2), which combines the cooled warm current with the cold current, so that in the resulting wet steam, the liquid component is greater than when directly relaxing in an adiabatic choke.

2. Cooling system according to claim 1, characterized in that the inflowing fluid, work equipment containing one or more substances stream (working fluid stream) in a compressed Liquid state or a boiling state, a Wet steam condition, a saturated steam condition or one superheated steam condition.   3. Cooling system according to claim 1 or 2, characterized in that the working fluid flow increases next isobarically cooled in the heat exchanger (WT) and in the throttle D is partially relaxed, so that it is in a liquid-vapor mixture is transferred. 4. Cooling system according to claim 3, characterized in that the liquid-steam mixture is separated under the influence of gravity in the separator S in the steam flow _D and the flow of boiling liquid _L. 5. Cooling system according to one of claims 1 to 4, characterized in that the initially cold steam flow ( _D ) after passing through the heat exchanger (WT) and the resulting heating by a regulating valve RV1 in the cooling vortex tube (KWR) in which it occurs further relaxed with the formation of a swirl flow and cooled by heat dissipation of the hot gas flow formed in the vortex tube in the hot flow cooler WK, and that the flow of boiling liquid m _{L is expanded} via a regulating valve RV3 and, after combining with the cooled steam flow mD, the system as a wet steam flow (L, V ) leaves. 6. Cooling system according to one of claims 1 to 5, characterized in that the ratio of the pressure drop p _D occurring in the throttle D to the pressure drop p occurring in the cooling vortex tube or in the regulating valve (RV3) is between 1 and 30. 7. Cooling system according to one of claims 1 to 6, characterized in that the mass ratio of the steam flow _D to the liquid flow _{L is} between 5% and 50%. 8. Cooling system according to one of claims 1 to 7, characterized in that the entry speed of the steam flow into the cooling vortex tube (KWR) at least 50% and at most 100% of the speed of sound in the entry state. 9. Cooling system according to one of claims 1 to 8, characterized in that the speed of the Swirl flow of the on the walls of the cooling vortex tube (KWR) expanding steam flow in the direction of the vertical Pipe axis upwards at least 10% and at most 60% of the speed of sound of the steam in the Entry state is. 10. Cooling system according to one of claims 1 to 9, characterized in that the hot gas stream ^H exiting the hot-stream cooler (WK) cooled additionally passed through a heat exchanger built into the separator (S) and only thereafter with the cold stream _c emerging from the cooling vortex tube combined via the regulating valve (RV2) and then fed to the liquid stream _L relaxed by the valve (RV3) ( FIG. 7). 11. Use of a cooling system or a cascade connection of such systems in a parallel or serial manner according to one of claims 1 to 10 in heat pumps and refrigeration machines with compression technology, absorption technology, adsorption technology or a combination of these techniques in a single-stage or multi-stage design for mono- or multivalent operation by replacement the adiabatic expansion valve or the adiabatic expansion nozzle through the cooling system ( 1 ). 12. Use of a cooling system or a cascade connection such systems in parallel or serial Way according to one of claims 1 to 10 in plants of Energy and process engineering for exothermic relaxation or cooling industrial brines and the like Working fluids as a replacement for one or more adiabatic Relief valves.