DE3111469A1 - Multi-stage compression cold-vapour machine with heat accumulator - Google Patents

Abstract

A two-stage or multi-stage compression refrigerating installation is described, the characterising feature of which is the arrangement of a heat accumulator in the heat transmission between the individual stages. This heat accumulator, which is arranged between evaporator and condenser of the individual stages, can preferably also be a latent-heat accumulator which makes possible a stabilisation and optimisation of the operation by approximately constant temperature of the heat transmission. Even the temporally delayed setting in operation of its stages is brought about by the heat accumulation.

Description

Prof. Dr.-Ing I Hermann "Schwind *" "80/13598-Hf Small Floraweg 34 /.

4600 Dortmund 50

Dr.-Ing. Dieter Wolff
Offenburger Strasse 6

7030 Boeblingen

Multi-stage compression cold steam engine with heat storage

The invention relates to a multi-stage compression cold steam engine, the substantially different pressure levels from at least two refrigerant circuits and at least one medium-pressure heat exchanger connecting the individual circuits with integrated heat storage, preferably with a latent heat storage.

The following explanations relate to a two-step process. This essentially consists of one an evaporator, a throttle valve and a compressor containing low-pressure circuit and a condenser, a throttle valve and a compressor containing high pressure circuit, and one of the two circuits connecting, medium-pressure heat exchanger with integrated heat storage.

Such machines are either in a cascade connection or with intermediate expansion in the connecting the two circuits Heat exchanger operated. In the first case, two different refrigerants can be used, with im Heat exchanger accepted a temperature difference must become. In the second case, both circuits are operated with the same refrigerant, creating an intermediate expansion becomes possible with direct heat transfer in the heat exchanger.

3111463

Depending on the technical design or performance of the two circuits, the Heat exchanger a medium pressure eir., Which is between the operating pressures of the evaporator in the low pressure circuit and the condenser is in the high pressure circuit. For example, according to the magazine "Kältetechnik", 13th year, booklet 6/1961, pp. 210 to 216, it is known that the operation of the overall system is optimal when the operating pressure in that heat exchanger is in a certain relationship to the operating pressures in the two circuits. In practical operation this is the optimum pressure but rarely achievable, since mostly the heat supply to the evaporator and / or the heat dissipation from the condenser fluctuates considerably due to the given operating conditions, which gives the overall system a discontinuous appearance from the outside Operating behavior is imposed.

The object of the invention is therefore to improve the machine of the type specified at the outset so that it operates stably can be and also larger temporal shifts between the heat accumulation in the evaporator and the heat dissipation bridged in the capacitor.

This object is achieved with the characterizing feature of claim 1, because the heat accumulator installed in the connecting heat exchanger and, if necessary, according to claims 2 and 3 in heat pump operation or refrigeration system operation in the condenser and evaporator store heat in the event that the low-pressure circuit on the heat exchanger more Delivering heat than is being taken from the high-pressure circuit and vice versa. Depending on the design of the heat store, the two circuits can be operated separately Lich time; that is, one circuit is in operation while the other is at a standstill. This enables a more flexible mode of operation, which ultimately improves the overall economy. A favorable utilization of the low tariff power supply for driving the two compressors can also have an effect here.

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For heat storage are suitable next Einphasenspeichern preferred latent memories in which the high latent heat of the phase change is solid / liquid or liquid / solid utilized and where for economical operation and thermodynamically optimal storage temperature you ¹ Ch selecting an appropriately suitable storage medium can be specified. Thus, claims 4 bLs 7 characterize the design of the heat storage.

Finally, claims 8 and 9 indicate that the figure of merit of the overall system by switching on a heat exchanger in each circuit is significantly increased can be.

The invention is based on the drawings with several Embodiments explained; Fig. 1 shows a conventional two-stage compression

Cold steam machine with cascade connection and Fig. 2 one such with intermediate expansion in the the heat that connects the two circuits

carrier;

3 shows a heat accumulator according to the invention in connecting heat exchangers in a machine according to FIGS
Fig. 4 with a machine according to Fig. 2;

heat storage according to the invention also in the evaporator and condenser in a machine according to. Fig. 1 and

in a machine according to Fig. 2; 7 shows a machine according to the invention with additional Heat exchanger in the high-pressure or low-pressure circuit,

8 shows a heat accumulator according to the invention in the heat exchanger of a machine according to FIGS. 6 or 7 and 9 shows a heat accumulator according to the invention in the heat exchanger of a condenser or evaporator Machine according to Fig. 5.

Fig. 4th Fig. 5 Fig. 6th Fig. 7th

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1 and 2 show the current state of the art. The two-stage compression steam engine shown in Fig. 1 has a low-pressure circuit in which an evaporator 1 is arranged between a throttle valve 4 and a compressor 2, and also a high-pressure circuit in which a condenser 6 is arranged between a throttle valve 7 and a compressor 5 . A heat exchanger 3 under medium pressure connects these two circuits indirectly.
10

According to the two-stage compression cold steam engine shown in FIG the two circuits with the connecting heat exchanger 3 are directly coupled.

According to Fig. 3 is at a gem..Fig. 1 trained machine a heat accumulator 8, preferably a latent heat accumulator, is attached in the heat exchanger 3, and accordingly 4 with a machine designed according to FIG.

5 and 6 show the attachment of an additional Heat accumulator 9 or 9a in a machine designed according to FIG. 1 or according to FIG. 2 in the condenser 6 for operation the machine z. B. as a heat pump, or in the evaporator 1 to operate the machine z. B. as a refrigeration system.

7 finally shows a two-stage compression cold steam engine according to the invention whose total capacity figure by attaching a heat exchanger 10 resp. 11 can be increased significantly in the low-pressure or high-pressure circuit. The heat exchanger 10 is between Evaporator 1 and low pressure compressor 2 arranged and on its other side between the under a medium pressure standing heat exchanger 3 and the throttle valve 4 switched. The heat exchanger 11, however, is between the condenser 6 and a throttle valve 7 leading to a medium pressure heat exchanger 3 and arranged connected on its other side between the heat exchanger 10 and the compressor 2 of the low-pressure circuit.

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According to FIGS. 8 and 9, the heat accumulator according to the invention is 8 or 9, 9a with the one under medium pressure Heat exchanger 3 or the condenser 6 or the evaporator 1 assembled. In its housing 22 is within an outer tube 16, an inner tube 17 attached coaxially and the cavity formed between them by transverse Ring plates 12 divided; Between these there is a heat storage mass 13, 7, preferably a latent storage mass.

The heat exchanger 3 shown in Fig. 8 with heat storage 8 is used in the machines according to FIGS. Of the four pipe sockets of the housing 22 is the nozzle 19 mü the pressure side of the compressor 2, the

1 [j connection 20 with the suction side of the compressor 5 and the connection 21 with the inlet side of the valve 4 connected.

The heat exchanger with heat accumulator shown in FIG. 9 8 is used in a machine as shown in FIGS. If the housing 22 with a heat accumulator 8 for the medium pressure heat exchanger 3 according to Fig. 3 and 5 equipped, so, of the two pipe sockets of the housing 22, the socket 18 with the outlet side of the valve is again and the nozzle 1S is connected to the suction side of the compressor 5. In this case, the housing 22 and the enclosed Space-penetrating inner tube 17 is with its nozzle 20 with the pressure side of the compressor 2 and with his Connection piece 21 connected to the inlet side of valve 4. If this housing 22 is provided with a heat accumulator 9 or 9a for the condenser 6 or the evaporator 1 according to Fig. 5, 6 and 7, the connector 18 with the valve 7 or the valve 4 and the connector 19 with the pressure side of the compressor 5 or connected to the suction side of the compressor 2. The 5 nozzles 20 and 21 are on one external heat sink or connected to a heat source.

Claims (9)

Patent claims: Multi-stage compression steam engine, essentially consisting of at least two refrigerant circuits, with one compressor and one throttle valve in each circuit and one evaporator in the low-pressure circuit and a condenser in the high pressure circuit, as well as at least one, the circuits connecting, Medium pressure heat exchanger for direct or indirect heat transfer characterized, that a heat accumulator (8) is mounted in the heat exchangers (3) under medium pressure (Fig. 3, 4). 2. Machine according to claim 1, characterized in that that for operation as a heat pump, the condenser (6) arranged in the high pressure circuit also has a heat accumulator 20 (9). 3. Machine according to claim 1, characterized in that that for operation as a refrigeration system, the evaporator (1) arranged in the low-pressure circuit also has a heat accumulator (9a). * K · W 4. Machine according to one of claims 1 to 3, characterized in that that at least some of the heat accumulators (8, 9, 9a) are designed to be identical to one another. 5 5. Machine according to claim 4,
characterized, that heat accumulators are designed as latent accumulators. 6. Machine according to claim 5,
characterized, that each heat accumulator (8, 9, 9a) with the medium-pressure heat exchanger (3) or the Condenser (6) or the evaporator (1) is assembled, wherein in the enclosed space of a housing (22) with four connecting pieces (18,19, 20,21) an outer tube (16) with a coaxial inner tube (17) attached and the cavity between the outer and inner tubes is divided by transverse ring plates (12), between which there is a heat storage mass (13) (Fig. 8, 9). 7. Machine according to claim 6,
characterized, that the inner tube (17) penetrates the housing (22), its enclosed space and in two nozzles (20, 21) passes (Fig. 9). 8. Machine according to one of claims 1 to 7, characterized in that that in the low pressure circuit between the evaporator (1) and the low pressure compressor (2) a heat exchanger (10) is arranged, on its other side between the medium-pressure heat exchanger (3) and connected to the throttle valve (4) of the evaporator (1) (Fig. 7). ν: - · - :: ■ 311U63 9. Machine according to one of claims 1 to 8, characterized in that that in the high-pressure circuit between the condenser (6) and a medium-pressure heat exchanger (3) leading throttle valve (7) a heat exchanger (11) is arranged on its other Side is connected between the heat exchanger (10) and the compressor (2) of the low-pressure circuit (Fig. 7).