DE3515560A1 - Heat engine for using environmental heat, in particular atmospheric heat - Google Patents

Abstract

The invention relates to a heat engine for using inherently balanced environmental heat such as, e.g., normal atmospheric heat or heat from water. It is particularly suitable for relatively large stationary power plants (power stations). Such heat engines can be operated in a closed or open cycle. In the case of an open cycle (Fig. 1), atmospheric air is sucked in directly via a compressor, and the hot compressed air is fed to a binary alloy nozzle via which the air (likewise atmospheric) is sucked in. The mixed product obtained, which has the new pressure and the new temperature, is expanded by a turbine and fed back - expanded and cooled - into the atmosphere. As a thermodynamic calculation shows, the mechanical work obtained from the mixed product in the turbine is greater than the work required to provide the compressed air at the compressor. The difference between the two works (W3,4-W212, Fig.2) can be dissipated to the outside in a useful way; it is the mechanical thermal equivalent of the atmospheric heat (s4-s1, Fig.3) lost at the turbine output. In the closed cycle, the working material is a gas or vapour of high specific heat in conjunction with a relatively high basic pressure. The take-up of heat from the environment, e.g. from the atmosphere, the water or the earth, is absorbed by a heat exchanger, and released to the colder gas expanded by the turbine. The ... Original abstract incomplete. <IMAGE>

Description

Heat engine for the use of ambient heat,

in particular from air heat The invention relates to a heat engine to use balanced ambient heat, such as B. water, air or ground heat. It works without the presence of a natural thermal gradient and is particularly suitable for larger stationary power plants, e.g. B. to drive electr. Generators in power plants.

In such heat engines, it is necessary that the to be supplied Heat is supplied with the working substance itself - the actual energy carrier, mixed with the compressed working material already in the work process and the resulting mixed product (with the new temperature and pressure) for work performance is relaxed via a turbine. The difference from supplied Compressor work and output turbine work can be considered effective work to the outside profitably be given.

Such heat engines can be operated in a closed or open cycle process. In open operation, atmospheric air (= supply air) is sucked in directly from the environment via a compressor, the hot compressed air obtained is fed to a two-substance nozzle, through which atmospheric air (= auxiliary air) is also sucked in. The mixed product obtained in the two-fluid nozzle is then fed to a turbine, relaxed and cooled and fed back into the atmosphere as "exhaust air". In the closed mode of operation, the cycle with a suitable gas as the working medium, z. B. helium or air, can be carried out, the heat absorption isobar takes place via a heat exchanger. The fact that the Relaxation of the working substance in the turbine, if the ambient temperature falls below the temperature, heat can be absorbed via the heat exchanger.

In the open cycle process, the heat absorption is at ambient temperature given by the fact that the warmer supply air from the colder exhaust air locally from each other enter and exit the heat engine separately.

The mixing process of inlet and outlet occurring within the two-substance nozzle Incidental air causes a decrease in temperature and pressure (increase in entropy) at the Hot compressed air provided by the compressor, but the remaining mixed product with the new temperature and the new pressure is sufficient to use polytropic (better isothermal) expansion via the downstream turbine to gain more work, than is necessary to drive the compressor. The resulting difference work can be used beneficially to the outside - at the expense of the air heat of the mixed product will. As the calculation shows, the greater the difference work, the the higher you compress and the more you move from adiabatic to isothermal compression and relaxation passes over.

The most important advantages that can be achieved with the invention exist especially in the fact that a practically inexhaustible and absolutely environmentally friendly Renewable energy source is made available at any time and at operable at any location. The heat engine can be used to drive electr. Generators are used in power plants and the previous energy sources (fossil and nuclear fuels) gradually substitute.

Such power machines for the use of balanced air heat have not yet become known. Efforts to heat energy from air or water Obtaining (ambient heat) has existed since the dawn of mankind. It the shrewdest minds have dealt with it. The number of their suggestions goes into the millions, but they ignored the laws of nature, especially the The fact that one can only get another form of energy at the expense of one form of energy (Conservation of energy law, 1st HS), or that heat only comes from a warmer body a colder body can pass over and not the other way around (entropy law or 2nd HS of thermodynamics).

Four embodiments of the invention are shown in the drawings and are described in more detail below. Fig. 1 shows the principle circuit diagram with compressor, two-fluid nozzle and turbine in an open cycle process (via the atmosphere open) Fig. 2 the pressure-volume diagram (P, v-Diagr.) belonging to Fig. 1 with true-to-scale Recording for 1 kg of intake air and 1 kg of auxiliary air Fig. 5 that too Fig. 1 associated temperature-entropy diagram (T, s-Diagr.) Fig. 4 an exemplary embodiment according to the principle circuit diagram Fig. 1 Fig. 5 an embodiment as Fig. 4, however with a Laval nozzle used instead of the turbine and a downstream wind turbine or Pelton wheel Fig.5.1 A partial drawing for Fig. 5 Atb. 6 shows an embodiment with 2-stage compression and open cycle Fig. 7 an exemplary embodiment with single-stage compression and closed cycle process The working principle, according to Fig. 1, is simple. Atmospheric air is sucked in via the compressor, Polytropically compressed, fed to a two-fluid nozzle in which also atmospheric Air (= additional air) is sucked in and mixed with the compressed hot air. That The mixed product is produced at a correspondingly lower temperature (the mixed temperature tm) and reduced pressure (the mixed pressure pm) are fed directly to the turbine and Polytrop expands. The work gained is, according to Fig. 4 and 5, on the one hand fed directly to the compressor via a drive shaft, while the remaining Work (= differential work) is profitably passed on to the outside world. To this operating condition To achieve this, the compressor must first be "started".

In the embodiment according to Fig. 4, the relaxation of the Mixed product respectively. of the mixed working material via a normal gas turbine.

In the embodiment according to Fig. 5, the relaxation takes place via a Laval nozzle, in which the air jet is initially at high speed (in high kinetic energy) is implemented with simultaneous temperature reduction. Afterward the kinetic energy of the air jet is generated via a wind turbine (or Pelton wheel turbine) transformed into rotational energy, as indicated in Fig.5.1. Which of the two modes of operation is more advantageous, depends on the size of the operating pressure and the intended use away. Very high operating pressures can generally be more economical with a Laval nozzle (with less loss) than directly via a gas turbine or piston engine. Should the heat engine only be used for thrust purposes - like a rocket motor will, then the downstream wind turbine only needs to drive the compressor be measured. The differential work is then push work in this operational case (Use e.g. to drive vehicles).

Both operating modes as shown in Fig. 4 and 5 work without a heat exchanger. This means that the intake and bypass air can be taken in without any loss of temperature be used. The cooled, used exhaust air is immediately released back into the atmosphere fed; it can also be used for cooling purposes, e.g. B. in cold stores, continue to be used.

The operating mode according to Fig. 7 works with a heat exchanger. she has compared to the designs according to Figs. 4 and 5, the advantage that their basic pressure (clamping pressure) higher than that of the atmosphere can be provided, so that with the same air flow rates - and thus with the same performance - the compressor and the turbine with accordingly smaller dimensions can be made. However, it has the disadvantage that a relatively large heat exchanger must be used. With him you can next to the Air heat but also water heat, ground heat or solar heat (radiant energy) use. In particular, however, water heat (sea, lake or river water) can contribute relatively high and almost constant upper temperature can thus be used (also in cold seasons at approx. 40C »constant).

In order to improve the effective labor gain per kg of working material throughput, must be used with all versions with the highest possible mixing pressure. This can be achieved with a relatively large saving in labor when using several compressor stages provide with respective intermediate cooling. This saving in labor also increases the effective useful work (differential work), since correspondingly less work for the Compressors must be recirculated. With Fig. 6 is in principle such a design shown with 2 compressors. The intercooling, which is a Is equivalent to the dissipation of waste heat to the outside, takes place through the air itself, i. H. the Energy content (internal energy) is fully retained in the system (waste heat release on your own system!). Thus, the heat engine (with a closed cycle) only mechanical work (no waste heat) released to the outside.

This would be a further improvement in terms of energy density possible by adding an aerosol of high to the auxiliary air (with open operation) spec. Mixed in with heat, e.g. B. an H20 aerosol. The working material can be stored in this roller first isothermal and then adiabatic relaxation and thus the useful heat surface (in the T, s diagram) enlarge.

All four versions work at any ambient temperature level roughly equivalent, since the size of the temperature drop at the turbine outlet is independent is from the level of the inlet temperature. Because the size of this temperature difference is achieved solely through the relaxation of a pressure that is always of the same magnitude (Mixed pressure) generated.

This property opens up the possibility of ever lower expansion end temperatures to advance by continuously removing mechanical work from a limited heat reservoir (Application as "self-sufficient refrigeration machine", because it supplies its drive work itself and also gives off excess work (differential work) to the outside world). This attribute also makes their mode of operation, especially with a closed cycle process (Fig. 7), i.e. when using a heat exchanger, is more attractive because of the high heat gradient - to absorb ambient heat - is generated and thus the heat exchanger with correspondingly smaller heat surfaces can be carried out.

In order to demonstrate the functionality of the present invention, was the open cycle process for the single-stage version calculated thermodynamically. The underlying and determined condition values are entered in Fig. 1-3. The polytropic factor was used for the polytropic compression and relaxation of the air n = 1.3 chosen. There was an amount of air to be compressed of 1 kg and an amount of auxiliary air of 1 kg at each OOC and 1 bar (or 1.013 bar = 760 Torr).

Example The theoretical compression work for 1 kg of gas results in Nm J The special gas constant Ri for is 287 or 287 kg K kg K With the underlying state values T1 = 00C = 273 K, P1 = 1 bar, P2 = 10 bar, n = 1.3, the compression work to be applied is: and with isothermal compression to p2 10 = Ri. T1. ln = 287 Nm / kgK. 273. ln 1 = 180.4 kj / kg.

The compression temperature T2 results from to The mixing temperature tm, 3 results in general from Since the same masses (m1 = m2) and the same spec. If there is warming (c1 = c2) for the supply and bypass air, the mixed temperature is t1 + t2 0 + 191 tm, 3 = = = 95.5 # 95 ° C.

2 2 The mixing pressure results from the fact that there are equal mixed quantities, to p1 + P2 1 + 10 Pm, 3 = 2 = 2 = 5.5 bar.

With the mixed values tm, 3 = 95 ° C, pm, 3 = 5.5 bar, m3 = 2 kg air and p4 = 1.1 bar output pressure, a recovery work of = 2. -142 = -284 kJ / 2kg (total recovery work from 2 kg of air) With isothermal expansion, on the other hand, one would get a recovery work of p4 1.1 m3.4, is, 2kg = 2. Ri. T3. ln = 2. 287 Nm / kgK. 273. in p3 5.5 = 2 126.1 = 252.2 kJ / 2kg The work Wab that can be transferred to the outside results from the difference between the two work processes a) with polytropic operating mode Wab, poly = m3.4, poly, 2kg - m1, 2, poly, 1kg = 284 - 238 = 46 kj / 2kg = effective useful work b) with isothermal operation Wab, is m3.4, is, 2kg m1.2, is, 1kg 252.2 - 180.4 = 72 kJ / 2kg = effective useful work Since the isothermal mode of operation (compression and expansion) is difficult to achieve in practice, the polytropic mode of operation with its less favorable efficiency has to be accepted. From the theoretical gain in work, about 10% must be deducted for machine losses (flow and mechanical friction losses), so that the real usable work that can be removed results in about 40 kJ / 2kg.

The final expansion temperature T4 results from polytropic mode of operation The utility values at the turbine result from a) heat gradient: aT = 95.5 + 18.8 = 114.3 0C b) pressure gradient: #pp = 5.5 - 1.1 = 4.4 bar around the P, To be able to record the v-diagram to scale, the individual corner points with the volume must be known. The initial volume V1 for 1kg air at 0 ° C, 1 bar, results in 1 1 m³ V1 = = = 0.7734 0 3 kg 1.293 kg / m3 V3 results in the expansion via the two-substance nozzle to T2 273 + 191 m³ = V2 = 0.1316 = 0.1657 T3 273 + 95.5 kg and the mixed volume with 1 kg of auxiliary air (at the same temperature and at the same pressure) as m³ = 2. v3.1kg = 2. 0.1657 = 0.3314 ### These volume values, calculated from the pressure ratios, are entered in the P, v diagram, Fig. 2.

The volume can also (for control purposes) be determined from the temperature alone m³ v1 = 0.7734 kg (as determined above) v3 results from relaxation in the two-substance nozzle to T2 273 + 191 m³ v3.1kg = v2 T3 = 0.1320 # 273 + 95.5 = 0.1662kg, T3 273 + 95.5 kg and the mixing volume with 1 kg of additional air v3.2kg = 2. v3.1kg = 0.3324 m³.

2kg These volume values, determined from the temperature, agree with the volume values calculated from the pressure ratio, apart from slight calculation rounds.

This proves mathematically that it is now possible after all to construct a periodically working machine that does nothing more than Release of mechanical work and corresponding cooling of a heat reservoir 1) The contrary opinion held so far lacks any physical basis; only previous experience speaks in favor of it, because it has not yet been given to anyone the functionality of such a machine has been successfully demonstrated, neither in practice still theoretically.

1) What is meant is a heat reservoir of uniform temperature, which is in internal equilibrium, e.g. B. normal water or air heat.

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Claims (4)

Patent claims heat engine for the use of ambient heat, in particular from air heat, characterized in that that of the heat engine The heat to be supplied is supplied with the working substance containing the thermal energy itself is, with a two-fluid nozzle or similar. Establish with that already in the work process existing and compressed working material is immediately mixed with the new one Temperature and the new pressure (mixed temperature and mixed pressure) immediately above a gas turbine or a Laval nozzle with or without a connected wind turbine, is relaxed. 2. Heat engine for using ambient heat according to claim 1, characterized in that the cycle is operated open or closed is, with open operation, the atmospheric air directly from the environment sucked in, the heat via a heat exchanger when the operating mode is closed constant pressure (isobaric heat absorption) is absorbed from the outside and when open or closed mode of operation for each single or multi-stage version, intercooling (= Waste heat emission) through the working substance itself absorbed via the two-substance nozzle is made. 3. Heat engine for using ambient heat according to claim 1 and 2, characterized in that (for the purpose of increasing the energy density) when open Mode of operation of the atmospheric air sucked in via the two-substance nozzle an H20 aerosol is mixed in and a working medium (gas) with closed operation the highest possible specific heat at a relatively high base pressure is. 4. Heat engine for the use of ambient heat according to one of the Claims 1 to 3, characterized in that when the operating mode is closed (Fig. 7) and the heat engine draws the ambient heat from a limited heat reservoir is operated at the same time as an "autarkic refrigeration machine" and as an 8Kraftmaschine ".