WO2008017431A1

WO2008017431A1 - Heat pump

Info

Publication number: WO2008017431A1
Application number: PCT/EP2007/006902
Authority: WO
Inventors: Edmund F. Nagel
Original assignee: Delunamagma Industries Gmbh
Priority date: 2006-08-10
Filing date: 2007-08-03
Publication date: 2008-02-14

Abstract

The invention describes a heat pump that can be used for example as a heating installation or as a cooling installation. The heat pump includes an evaporator (2), in which a fluid is continuously evaporated at low pressure, taking up heat from the environment, and a condenser (6), in which the fluid is continually condensed at high pressure, releasing heat to the environment. The pressure levels required for the condenser and the evaporator are generated by a vapour jet pump (16) with externally heated Laval blowing nozzle (14).

Description

heat pump

The present invention relates to a heat pump with an evaporator in which a fluid is continuously evaporated at low pressure while absorbing heat from the environment and a condenser in which the fluid is continuously condensed at high pressure with heat release to the environment.

Such a heat pump has several uses: when the condenser is located within a room and the evaporator is outside, the fluid that is usually used for liquefied gas carries heat from outside the room to within. The heat pump in this case serves as a heating system for the room. On the other hand, when the evaporator is disposed inside a room and the condenser is outside, the fluid, which in this case is also called a refrigerant, transports heat from within the room to outside. The heat pump is used in this case as a cooling system (also called "chiller") for the room.

The published patent application DE 3200436 A1 shows by way of example that injectors / ejectors can only be used to assist in discontinuously operated absorption heat pumps. But even in continuous compressor heat pumps, the steam jet pump can only be used for support.

It is known from the published patent application DE 10317875 A1 that ejectors for supporting a refrigeration system compressor can form a low initial pressure. In the Laval friction nozzle, the motive steam condenses during expansion and even ice crystals are formed. In heat pump technology the injector / ejector is therefore used only as a pressure booster, but not as the sole pressure generator.

The object of the invention is to replace the conventional compressor of a heat pump, as used for example in a heating or cooling system, by an injector / ejector, which can provide the required pressures alone, ie without a downstream compressor.

The object is achieved by a heat pump according to claim 1. Further developments of the invention are specified in the subclaims.

This requires the use of an externally heated Laval nozzle. This has been described in detail in all its functions in the Austrian patent applications A 412/2005, A 608/2005, A 1660/2005 and A 1984/2005.

By heating the propulsion jet, in particular during the expansion in the motive nozzle, substantially higher outlet velocities are achieved at the motive nozzle, and the motive vapor is, above all, completely gaseous at the outlet. Thus, the required pressure levels are generated exclusively by the steam jet.

Preferably, the propulsion jet in the Laval propulsion nozzle consists of the fluid used in the heat pump. The propellant is taken up in a liquid after the condenser in a bypass and fed via a pressure pump of the heated Laval nozzle. The pressure pump generates pressures of preferably well above 100 bar, but it does not deliver gas, but only the liquid fluid whose volume is much smaller than in the gaseous state.

DU / SV / 31 0707 The heat supplied to the heated steam jet pump from the outside can, for example, be waste heat from an internal combustion engine. The required heat is supplied to the steam blast from a heat exchanger on the exhaust via thermal connections to the evaporator / steam superheater and the Laval -reibdüse.

Of course, other heat sources can be used as an internal combustion engine. These heat sources may consist of solar heat, heat from the combustion of a combustible fuel in a burner, process heat, etc. This application can be used, for example, for camping refrigerators, solar air conditioners, etc. or for heat pumps for domestic heating, when the primary heat source on the evaporator exceptionally alone is no longer sufficient, the primary heat source, for example, air and the additional heating is a wood heating. The heat can be supplied via a heat exchanger to the gas, before entering the heat exchanger to the motive nozzle and the pre-evaporator. Of course, it is also possible to provide a direct thermal connection from the additional heat source to the heat exchangers of the motive nozzle and the evaporator / superheater.

Preferably, the divergent portion of the Laval drive nozzle is at a shallower angle than 2 °, and the total driving jet is split into a plurality of discrete, juxtaposed smaller Laval drive nozzles. As a result, an enlargement of the heat exchange surface of the propellant gas to the heat exchange surface of the Laval-Treibdüsen inside is achieved. A conventional motive nozzle would have in the ratio of available Δt a heat transfer surface several hundred times too small to the propellant gas.

In the evaporator / superheater the liquid influent refrigerant is vaporized by supplying heat from the outside and subsequently over-

DL7 / SV / 310707 hitzt. The overheating of the motive steam in the steam superheater saves heat exchange surface in the Laval friction nozzle.

Due to the supersonic velocity of the motive steam, the heat exchange surface in the Laval motive nozzle must be designed to be absolutely rectilinear, while the evaporator / superheater with its subsonic flow velocity of the propellant medium can advantageously be applied in an arbitrarily baffle manner.

The fluid, and thus each equally the motive steam of the injector / ejector, may consist of a CFC gas, CO2 or any other vaporizable fluid. The pressures to be generated by the heated injector / ejector depend on the evaporator / superheater used and the desired temperature gradient.

In one variant, the steam jet pump can also be designed only as an injector for overpressure generation or, in a further variant, also be used only as an ejector for generating negative pressure. The use as an injector or ejector, or a mixed operation, is dependent on the fluid and its evaporation / condensation temperature and on the available and desired temperatures.

Further features and advantages of the invention will become apparent from the description of embodiments with reference to the accompanying drawings.

1 is a schematic diagram of a heat pump operating as a cooling system according to a first embodiment of the present invention.

Fig. 2 is a schematic sectional view of a Laval nozzle.

DL7 / SV / 310707 FIG. 3 is a schematic sectional view of a vapor jet pump having two Laval driving nozzles. FIG.

4 is a schematic diagram of a heat pump operating as a cooling system according to a modification of the first embodiment.

5 is a schematic diagram of a heat pump operating as a heating system according to a second embodiment of the present invention.

First, with reference to Fig.1. a first embodiment of the present invention is described, in which the heat pump serves as a cooling system or chiller.

In a room 1 to be cooled, there is an evaporator 2 with a heat exchanger. The evaporator 2 is connected via an intake 3 with a mixing tube 4, which in turn is connected via a Überströmstutzen Ü 5 with a condenser 6 with heat exchanger. From the condenser 6, a liquefied gas line 7 leads to a liquid gas collecting basin 8. From the liquid gas collecting basin 8, a liquefied gas line 9 leads via a throttle 10 back to the evaporator 2. Thus, a closed circuit is formed, in which a fluid acting as a refrigerant can circulate ,

In operation, the fluid is continuously vaporized in the evaporator 2 at low pressure while absorbing heat from the environment and continuously condensed in the condenser 6 at high pressure with heat release to the environment. As a result, heat is removed from the room to be cooled 1 to the environment, and the space to be cooled 1 is cooled.

From the liquid gas collecting basin 8, a further liquefied gas line 11 leads via a liquid gas pump 12 to an evaporator.

DI7 / SVI31.07.07 fer / superheater 13. Connected to the evaporator / superheater 13 is a La Valve friction nozzle 14, which opens into the mixing tube 4 via a drive nozzle outlet 15. The evaporator / superheater 13, the Laval friction nozzle 14 and the mixing tube 4 form a steam jet pump 16, which generates the required pressure levels for the condenser 6 and the evaporator 2 during operation.

For this purpose, the steam jet pump 16 further includes a heat exchanger 17 which is connected in each case via a thermally conductive connection 18, 19 with the evaporator / superheater 13 and with the Laval-Treibdüse 14.

In the present embodiment, the heat exchanger 17 is connected to the exhaust 20 of an internal combustion engine 21 of an automobile.

In operation, a part of the waste heat of the internal combustion engine 21, which is passed through the heat exchanger 17 and the thermally conductive compounds 18, 19 to the evaporator / superheater 13 and the Laval -reibdüse 14 is sufficient even at the lowest engine utilization, for example, a car air conditioning fully to operate. This waste heat evaporates the liquid refrigerant in the evaporator / superheater 13, and above all, it heats the refrigerant during expansion in the Laval friction nozzle 14.

In Fig. 2, a Laval driving nozzle 14 is shown in section. It has a convergent blowing nozzle part 22 and a divergent blowing nozzle part 23. By flattening the pitch angle 24 of the divergent motive nozzle part 23, an extension of the Laval friction nozzle 14 takes place. With this extension of the divergent motive nozzle part 23, an increase in the heat exchange surface of the motive steam to the motive nozzle 19 anher. A conventional Laval nozzle has a surface area that could never transfer the required amount of heat.

OL7 / SV / 310707 As a rule, the heat exchange surface generally has to make up about 100 times more than a conventional Laval nozzle.

In Fig. 3, a further measure for increasing the heat exchange surface is shown. The total gas flow of the motive nozzle is divided among a plurality of small motive nozzles 14. In the figure, two blowing nozzles 14 are shown by way of example, however, three or more blowing nozzles 14 may be used. As a result, depending on the number of these small blowing nozzles, the surface is considerably enlarged while the passage cross-section of the individual blowing nozzles remains the same.

Of the liquid gas pump 12, which is driven by a (not shown) electric motor, the fluid is supplied to the evaporator / superheater 13, usually well above 100 bar. Due to the heat supplied to the evaporator / superheater 13, the fluid evaporates and becomes gaseous. In the evaporator / superheater 13, the gas still flows at subsonic speed, but reaches after the convergent nozzle portion 23 of the Laval nozzle 14 and the narrowest point in this nozzle in the divergent nozzle portion 24 of the Laval-Treibdüse 14 supersonic speed. From then on, the gas flow must no longer be diffracted in the straight flow direction. Otherwise there would be very bad enthalpy jumps.

By heating the Laval frictional nozzle 14, cooling of the refrigerant during supersonic expansion is avoided. In conventional Laval propelling nozzles, the motive steam condenses extremely badly during expansion and even forms ice crystals. As a result, conventional steam jet pumps achieve only very poor efficiencies and could previously at best be used as supporters of the compressor in refrigeration technology.

In the steam jet pump 16 according to the present embodiment, the heated refrigerant propelling jet is opposite to the

DL7 / SW31.07.07 conventional steam jet pump at a much higher speed and hot out of the Laval-Treibdüse 14 and is completely gaseous. So he has a much higher kinetic energy in the form of velocity of accelerated gas molecules. Due to the heating, however, the molecules are also really gaseous and do not condense into liquid as in conventional Laval nozzles or even solidify into ice crystals.

The subsequent pumping of the refrigerant in the injector mixing tube 4 is therefore very efficient. In the mixing tube 4, the blowing molecules collide many times with the delivery molecules. In the elastic shock kinetic energy of the driving molecules is transferred to the conveyor molecules.

However, a considerable proportion of the kinetic energy inherent in the driving molecules is also converted into heat. This heat leads to a heating of the gas, which depending on the gas mixing ratio between propellant and conveying gas, the propellant pressure used, etc, can reach> 100 ⁰ C. In compression shocks, the speed of the propellant gas mixture in the mixing tube 4 decreases to subsonic speed, and vice versa, the pressure rises to levels that could previously be achieved only with the compressors. The device according to the invention thus replaces the compressor completely.

The impulse transfer in the elastic shock of gaseous propellant molecules to the gaseous pump molecules succeeds to the same extent better, as a higher velocity of the propellant molecules is available and as the propellant medium proportionally gaseous. It is important to know that condensed motive steam or motive steam which has solidified into ice crystals does not in fact exert any pumping action on the gaseous pumping medium.

OU / SV / 31.07.07 The completely gaseous and hot propulsion jet of the steam jet pump 16 achieves a multiple of impacts on the pump medium compared to the partially already condensed motive steam of a conventional steam jet pump.

In the condenser 6, the gas releases its remaining heat to approximately the temperature value of the environment and condenses due to the reduced temperature and the prevailing overpressure. Now, the so liquefied gas flows partly as a propulsion jet for the steam jet pump 16 to the feed pump 12 and the other part via a throttle 10 to the evaporator. 2

In the throttle 10, the pressure of the LPG is greatly lowered. That's why it starts to boil and evaporates. The required heat of vaporization is removed from the environment in the evaporator 2. The heat transfer medium of the environment can be air, groundwater or the room to be cooled.

After the evaporator has now absorbed heat from the environment (use as a heating system) or has withdrawn heat to the room to be cooled (use as a cooling system), the vaporized so then gas flows into the mixing tube 4, from where the described continuous process proceeds again ,

When used in the car, the heated steam jet pump 16 is operated by the available waste as waste heat of the exhaust 20. As the only moving part, the cooling system has a liquid gas pump 12, which consumes only a few percent of the energy consumed by a comparable compressor chiller.

A modification of the first embodiment is shown in FIG. In this modification, the heat is used to heat the

DL7 / SV / 31.07.07 Laval nozzle 14 is not generated by an internal combustion engine of an automobile, but by a burner 25th

Alternatively, instead of an internal combustion engine or a burner, another heat source may also be used, e.g. a solar system, process heat, etc. This variety of possible heat sources also creates a variety of applicability of the invention. Such devices serve as, for example, camping refrigerator or as air conditioning, which is powered by solar heat. In sunny countries, for example, a sunlit roof may be used to generate the heat required to operate the air conditioning system of the underlying building via a solar panel.

The heat pump described in the first embodiment and its modification, which serves as a refrigerator or chiller, can also be used as a heating system when the condenser 6 is accommodated in a space to be heated.

Fig. 5 shows a heat pump that can be used as a heating system and equally as a cooling system, according to a second embodiment of the present invention. Components whose structure and function correspond to those of the first embodiment are identified by the same reference numerals.

The heat pump according to the second embodiment differs from that of the first embodiment in that the condensed and heated gas exiting the mixing tube 4 is not supplied to the condenser 6 via the spill port 5 but via a gas line 26. This gas line 26 is thermal conductive connections 27, 28 are connected to the evaporator / superheater 13 and to the Laval drive nozzle 14.

DI7 / SV / 31 0707 Thus, heat is supplied to the evaporator / superheater 13 and the Laval friction nozzle 14 from the hot gas, which is supplied from the mixing tube 4 through the gas line 26 to the condenser 6. About an additional heater 29, 26 more heat can be supplied to the gas in the gas line.

The heat supplied to the heated steam jet pump from the outside arises during the compression of the gas in the mixing tube of the injector. Heat that is generated in the injector, so for the most part in an internal heat cycle the pre-evaporator and especially the Laval -reibdüse recycled. The result is thus the effect that the Laval friction nozzle can generate pressures like a conventional compressor.

DL7 / SV / 31.07.07

Claims

PATENT CLAIMS

A heat pump having an evaporator (2) in which a fluid is continuously evaporated at a low pressure with heat absorption from the environment, and a condenser (6) in which the fluid is continuously condensed at high pressure with heat release to the environment, thereby characterized in that the required pressure levels for the condenser and the evaporator by a steam jet pump (16) are generated with externally heated Laval-Treibdüse (14).

2. Heat pump according to claim 1, characterized in that the steam jet of the heated Laval-Treibdüse (14) from the

Fluid of the heat pump is formed.

3. Heat pump according to claim 1, characterized in that the heat pump is a cooling system and the steam jet of the heated Laval-Treibdüse (14) is formed from the refrigerant of the cooling system.

4. Heat pump according to claim 3, characterized in that the refrigerant and the motive steam of the injector / ejector

(16) consist of a CFC gas or CO ₂ .

5. Heat pump according to claim 1, characterized in that the heat pump is a heating system and the steam jet of the heated Laval -Treibdüse (14) is formed from the consisting of liquid gas fluid heating system.

6. Heat pump according to claim 5, characterized in that the motive steam of the steam jet pump (16) and the conveying medium of the mixing tube (4) consist of CO ₂ .

DI7 / SW310707

7. Heat pump according to one of claims 1 to 6, characterized in that the driving medium for the steam jet pump (16) is received in a bypass to the condenser (6) and fed via a pressure pump (12) of the steam jet pump.

8. Heat pump according to one of claims 1 to 7, characterized in that the steam jet pump (16) contains an evaporator / superheater (13), in which the liquid flowing fluid evaporates by supplying heat from the outside and is subsequently overheated Ü.

9. Heat pump according to one of claims 1 to 8, characterized in that the steam drive the required heat from a heat exchanger (17) via thermal connections (18, 19) to an evaporator / superheater (13) and the Laval -reibdüse (14) is supplied.

10. Heat pump according to one of claims 1 to 9, characterized in that the steam jet pump (16) externally supplied heat, for example, waste heat of an internal combustion engine (21).

11. Heat pump according to one of claims 1 to 9, characterized in that an evaporator / superheater (13) and the La val- drive nozzle (14) via thermal connections (27, 28) by heat from compressed gas, which in the mixing tube ( 4) is formed, heated.

12. Heat pump according to claim 11, characterized in that an additional heater (29) for heating the in the mixing tube (4) resulting compressed gas is provided.

DL7 / SV / 310707

13. Heat pump according to one of claims 1 to 12, characterized in that alternatively or additionally heat sources are used which consist of solar heat, heat from the combustion of a combustible fuel in a burner (25), process heat, or the like.

14. Heat pump according to one of claims 1 to 13, characterized in that the divergent part of the lava1-driving nozzle (14) has a shallower angle (24) than 2 °

15. Heat pump according to one of claims 1 to 14, characterized in that the total driving jet to a plurality of individual, parallel juxtaposed, smaller Laval-Treibdüsen

(14).

16. Heat pump according to one of claims 1 to 15, characterized in that the steam jet pump (16) is used in a variant only as an injector for positive pressure generation or in another variant only as an ejector for generating negative pressure.

OL7 / SVB1.07.07