DE3527438A1 - Heat engine for using environmental heat - Google Patents

Abstract

The invention relates to a heat engine for using environmental heat of uniform temperature, which is in a state of internal equilibrium such as, e.g., normal heat from air or water. Apart from directly driving vehicles, it is particularly suitable for relatively large stationary drives such as, e.g., for generating electrical energy in power stations. In order to be at all able to use heat of uniform temperature, i.e. without the presence of a natural thermal gradient with respect to a heat reservoir located outside the heat engine, according to the invention the heat engine is designed with a two-part gas circuit. In this case, the working medium of the one subcircuit is compressed via a two-stage compressor with intermediate cooling and fed to a binary nozzle, while the other part of the working medium (cold and uncompressed) is sucked in directly by the binary nozzle after previous absorption of heat from the environment and of the waste heat derived from the intermediate cooling. The mixed product which is obtained from the two components of working material from the two subcircuits in the binary nozzle and which has the new pressure (the mixed pressure) and the new temperature (the mixed temperature) is finally fed to an expansion machine (gas turbine), and fed again expanded and cooled to the environment (in the case of open operating mode) or to the heat exchanger (in the case of closed operating mode) for the purpose of renewed absorption of heat. Since before this the working gas ... Original abstract incomplete.

Description

Heat engine for the use of environmental heat

============================================== The invention concerns a heat engine for the use of ambient heat of uniform temperature, the is in inner equilibrium, such as B. normal air or water heat. In addition to driving vehicles, it is particularly suitable for larger stationary ones Systems such as B. to drive electr. Generators in power plants.

Such heat engines consist of a two-part working material cycle. They can be operated in an open or closed cycle process. At (over The atmosphere) open cycle becomes immediately atmospheric through the one partial circle Air is sucked in from the environment by means of a single or multi-stage compressor, compressed and fed to a two-fluid nozzle. The other partial circle is also atmospheric air - sucked in by means of the air compressed by the compressor. The mixed product obtained in this way from the two working substance components in the two-substance nozzle with the new pressure (the mixed pressure) and the new temperature (the mixed temperature) is finally via any expansion machine, preferably via a Gas turbine, relaxed and cooled, returned to the atmosphere. When closed In contrast to the open mode of operation, a circular process is also a heat exchanger used, over which the expanded and cooled working gas in the expansion machine first absorbs heat from the environment before it comes from the compressor and the two-substance nozzle sucked in again and entered into the cycle.

As a thermodynamic calculation now shows, this results despite the pressure and temperature drop present at the two-substance nozzle (= increase in propensity) from the mixed product of the two working substance components when relaxing over the Gas turbine a noticeably greater mechanical recovery work than to provide the compressed air for which an agent component was required on the compressor. It is thus - after a previous start-up by a starter motor - possible the to divert the mechanical work required for the operation of the compressor from the turbine (= Return work) and the remaining turbine work (= differential work) to the outside dissipate and use.

This differential work is the mechanical heat equivalent of that of Total heat absorbed outside (1st law of thermodynamics).

In an open cycle, this is the difference in heat from the atmospheric warmth of the air supplied from the outside and released again to the outside. In the closed cycle process, this is the one from the environment via the heat exchanger Heat absorbed and transferred to the working material, which is also used as differential heat occurs and in this operating case between the inlet and outlet on the heat exchanger is entered.

So here too, as with all previously known heat engine processes, during expansion, only part of the working material heat passed through the expansion machine (= Differential heat) converted into mechanical work. However, since the new working principle the working substance accumulating at the turbine outlet during the expansion via the Allowing the turbine to cool below the ambient temperature level is heat absorption from the environment (even at very low temperatures) possible, d. H. an existing one Any heat potential, balanced in itself, at any upper temperature level can be removed down to a very low lower temperature level, respectively. in mechanical Work to be implemented. This is possible because of the mixing pressure on the two-substance nozzle for every current ambient temperature level, always in the same size from Compressor is generated.

This property also makes the heat engine to operate as a "A refrigeration machine is suitable when you consider the heat absorption from one compared to the environment makes more or less closed heat reservoir and the gained from it mechanical work to the outside, to the "upper heat reservoir of the environment". This can be achieved e.g. B.

through direct transfer of the mechanical work (from the in the temperature of the lower-lying heat reservoir) by means of a working shaft or in the form of electr. Work by means of electr. Lines with previous setting of the mechanical work in electr. Energy.

Since in the present thermal power plant only energy in the form of mechanical or electrical work (not in the form of low-temperature waste heat) is dissipated to the outside and this is equivalent to the ambient heat supplied from the outside, according to the 1st law of thermodynamics, there is one defined for the thermal power plant Theoretically 100% thermal efficiency:: Differential work dissipated to the outside n | th = differential heat absorbed from the outside This thermal efficiency is independent of the machine work or machine output carried out in each case because the ratio of work and heat is theoretically always of the same size and is therefore one ".

However, in order to be able to make a statement about the quality of the existing thermal power plant with regard to its internal working conditions, one can, for example, compare the compressor work and the total turbine work gained and define a so-called work efficiency n | W "total turbine work output Wt total compressor work applied ~ Wk = (equation 2) or by only putting the useful work that can actually be released to the outside (= differential work # Wab) in relation to the compressor work Wk and thus a so-called "effective work efficiency iw" defines total turbine work - total compressor work total compressor work As will be shown on the basis of a practical exemplary embodiment, according to the definition according to Eq. 2 for such a thermal power plant with two-stage compression (according to Fig. 8) a so-called "working efficiency" of about n | W = Wt / Wk = 136%, and according to Eq. 3 a so-called "effective work efficiency" of qnw Wt / Wk - 1 = = 1.36 - 1 = 0.36 = Instead of the work Wt and Wk, the corresponding temperature differences JTt and alk could also be used in equations 2 and 3. The corresponding equations are given on page 9.

Such a thermal power plant works with a higher "work efficiency" respectively "Effective working efficiency", the more multi-stage the compressor system is is, the higher the pressure ratio when generating the mixing pressure at the two-substance nozzle was chosen, the more you move from the adiabatic to the isothermal compression and relaxation of the working substance passes over both at the compressor and at the turbine (which is practical however, in terms of performance, it is very limited in terms of performance in the direction of isothermal compression and relaxation is) and the more lossless and more complete you get in a multi-stage compressor system Waste heat (q) arising from the intercooling is transferred to the heat absorbed via the two-fluid nozzle can transfer colder working material content.

Such thermal power plants to use heat from one on the Temperature level of the surrounding, balanced heat reservoir not known until today.

With the heat engine cycle processes that are common today, with so-called "single-circuit process management", this is not even possible, since the necessary Heat emission respectively Waste heat from the expansion machine to the environment a second, outside the thermal power plant located, in its temperature lower lying heat reservoir makes it necessary and not without at least the same amount of work , e.g. B. by means of a refrigeration machine can be produced.

With the new working principle, with so-called "two-circuit process management", the waste heat (which arises here through intermediate cooling) does not have to go outside the Thermal power plant to be dissipated; Rather, it can be internally (and thus also usefully) on the second working substance, which is absorbed via the two-substance nozzle, without being compressed transferred because the material taken from the environment (in the case of an open cycle) or the working substance discharged from the turbine (in the case of a closed cycle) its temperature is lower than the proportion of working substance compressed by the compressor. This means that there is an independent heat transfer that occurs through intercooling Waste heat is drawn in via the two-substance nozzle without any special effort internal working substance possible (entropy law or 2nd law of thermodynamics).

The advantages achieved with the invention are in particular: that a practically inexhaustible, regenerative energy source of relatively high Energy density is permanently available and works absolutely without environmental pollution can. She is at all times (day and night, summer and winter) and in every place operable where either air, water or radiant heat is present. she can replace the previously used fossil and nuclear energy sources, as they is far superior in the long run, both ecologically and economically.

Two embodiments of the invention are shown in the drawings and are described in more detail below. Fig. 1 shows the basic diagram of the Thermal power plant with 2-stage compression and open cycle process as well as (hinted at) with a heat exchanger for a closed cycle process Fig. 2 that of Fig.1 associated temperature-entropy-diagr. (T, s diagram) for the 2-stage compressor system Fig. 3 the T, s diagram for the expansion machine belonging to Fig. 1 Fig. 4 the Pressure-volume diagram (P, v-Diagr.) for the 2-stage compressor system belonging to Fig.1 Fig. 5 shows the P, v diagram for the expansion machine Fig. 6, which belongs to Fig. 1 Embodiment with an open cycle according to the principle diagram according to Fig. 1 Fig. 7 shows an exemplary embodiment with a closed cycle process according to the principle diagram Fig.l Fig. 3 a schematic diagram of the thermal power plant and the openly operated cycle according to Fig. 1, but with different operating data.

Fig. 9 the same as Fig.8, but in a 3-stage design Fig.10 Working principle a previously common heat engine as evidence of the impossibility to Use of environmental heat Fig. 10.1, 10.2, 10.3 P, v diagrams for the working principle according to Fig.10.

Descriptions The basic circuit diagram of the thermal power plant is in Ab5.1 for a cycle operated openly via the atmosphere as well - indicated by dash-dotted lines - for a directly closed cycle (with a heat exchanger) shown. The thermal power plant consists of the two Compressors kl and k2 for two-stage compression, the intercooler, the Two-substance nozzle for receiving and mixing the from outside or via the heat exchanger sucked in supply air and bypass air respectively. Working substance gas, as well as one of the Two-substance nozzle downstream expansion machine, which with the present working material (air with open, helium or compressed air in the closed cycle process) a normal gas turbine can be. To keep the thermal power plant (gas turbine plus compressors) in operation set, it must first be "started" by means of a starter motor (not shown here) will.

To get as clear a picture as possible of the operating conditions The thermal power plant was to be obtained for various operating states that were as practical as possible calculated thermodynamically. The selected and calculated state values are entered at the corresponding point in Fig. 1. The associated T, s and P, v diagrams are shown separately for the compressors and the turbines. So shows Fig. 2 and 4 show the progression of the state with a 2-stage compression in the T, s and P, v diagram and Fig. 3 and 5, respectively, the corresponding progression of the state for the expansion machine. Gas turbine.

A 2-stage compression with intermediate cooling was chosen because In addition to using the intercooling waste heat, there is also a significant amount of compression work can save in the provision of the required printing potential and thus (compared to a single-stage compression) the thermal power plant with significantly greater efficiency, and can therefore operate more economically than systems with only single-stage compression. Such a saving in labor is shown in Figs. 2 and 4; it encloses the heat respectively Work surface 2-3-4- (4).

With Fig. 6 and 7 is the thermal power plant shown in Fig. 1 again shown, but here in a more practical representation and each separately Operation; Fig. 6 shows the open and Fig. 7 the closed mode of operation Heat exchanger.

The operating data for Fig. 6 are the same as for Fig. 1. The Plant according to Fig. 7, since it works with a closed cycle process, can significantly higher basic pressure (= final expansion pressure). This has compared to the open mode of operation has the great advantage that you can use the same working material throughput (and thus with the same output) the entire thermal power plant (machines, pipelines, Two-substance nozzle, etc.) dimensioned significantly smaller and thus more cost-effective can produce as openly operated systems at basic atmospheric pressure.

Fig. 8 also shows (as with Fig. 1) an openly operated thermal power plant shown, but calculated with different operating data.

As can be seen, the pressure ratios at K1 and K2 were increased to 1/5 (a pressure ratio of 1/3 was selected in Figs. 1, 6 and 7). The intermediate cooling in state point 3 for the 2nd compressor stage was also increased to 20 ° C, which in practice is due to the heat loss during intermediate cooling. Although this requires a higher drive work for the compressor K2 (from 152.7 kJ / kg to 163.9 kJ / kg), the increase in effective useful work as a result of the increase in the pressure ratios exceeds this additional work, so that overall a higher work efficiency is achieved became. The theoretically achievable "working efficiency" according to equation 2 thus results from the operating data shown in Fig. 8 and on which it is based and the so-called "effective work efficiency" according to equation 3 The above measure brought an increase of (36.6 - 31.6) = 5.

The practically achievable work efficiency should be after deduction of the mechanical friction losses in larger systems are 35 ° k.

A 3-stage compressor system would achieve approx. 80% (Fig.9).

For the calculation of the theoretical compression work for t kg of gas, the general working equation (p.98, Techn.

used, with the special gas constant for air with Ri = 287 kg K or 287 J was substituted into the equation.

kg K Since a mixing ratio of 1: 1 has been selected for the two-substance nozzle was, d. H. 1 kg of incoming and outgoing air from both branches of the working substance must be used To calculate the turbine work, the above equation is multiplied by a factor of 2 will. In the turbine are thus 2 kg working substance, the mixed product, translated into work performance.

In the case of a 3-stage version (Fig. 9), the equivalent of 3 kg is transferred.

The final temperatures were given using the general equation determined.

The mixing temperature at the two-substance nozzle was calculated using the general mixing equation for gases Since the mixed quantities (m1 = m2) and the specific heats (c1 = c2) are of the same size in the present case, the mixed temperature results in the simplified form of The polytropic factor n was used in all specified operating cases (compression and expansion via machines) with n = 1.3 in the equations.

The flow losses were determined by choosing one versus the suction pressure correspondingly increased final pressure at the turbine outlet is taken into account.

This was in agreement with the 1st and 2nd law of thermodynamics proven that it is tested by means of a so-called 'two-circuit heat engine process, according to the invention, is possible from a standing at the temperature level of the environment, to gain mechanical work in itself balanced heat reservoir and this to cool down accordingly. With the so-called "single-circuit heat engine processes" that are common today this is basically not possible: At best, you could only go up to the inlet temperature relax at ambient pressure and the work obtained would be most if only that of the compressor work used. A differential work that as useful work could be carried away would not occur (Fig.1O, lo.l-1 ^.}).

Calculations for the designs in Fig. 1-6 Calculations for the execution Fig. 7 Calculations for the execution Fig. 8 Calculations for the execution Fig. 9 (3-stage) Calculations for the execution Fig. Lq, 10.1, 10.2 and 10.3 Evidence for the impossibility of using environmental heat with the previously common working principle for heat engines. Maximum work with "single-circuit" mode of operation, 2-stage compression, without intermediate cooling:

Claims (5)

Heat engine for the use of environmental heat, in particular of air or water heat, characterized in that the heat engine aws consists of a two-circuit gas-working substance cycle, one of which is a partial gas cycle Passed through a compressor with intercooling and the second uncompressed with the first is coupled via a two-substance nozzle and that in the two-substance nozzle Mixed product obtained from both working substance sub-circles (with the new temperature and the new pressure) of an expansion machine - preferably a gas turbine - is supplied to the work performance. 2. Heat engine for the use of environmental heat according to claim 1, characterized in that the compressor is preferably designed in 2 or 3 stages and the heat to be dissipated during intermediate cooling is transferred to the two-fluid nozzle Colder working material gas sucked in uncompressed from the environment or the heat exchanger is transmitted. 3. Heat engine for using environmental heat according to claim 1 and- 2, characterized in that the two-part cycle process either via the The atmosphere is open or, via a heat exchanger, operated closed. 4. Heat engine for the use of environmental heat according to claims 1-3, characterized in that the heat engine operated as a "refrigeration machine" is, with the heat to be dissipated from the deeper heat reservoir directly in Form of mechanical work (wave work) or in the form of electrical work by means of electrical lines from the heat reservoir, which is lower in temperature is discharged to the environment (environment). 5. Heat engine for the use of environmental heat according to claims 1-3, characterized in that the operated closed by means of a heat exchanger single or multi-stage cycle with a working gas of high specific heat and high base pressure (expansion pressure) is operated and the environmental heat to be absorbed for stationary power plants (power plants) preferably from sea, lake or river water and is preferably taken from the atmospheric air for vehicle drives (absolutely pollutant-free power drives).