DE3304729A1 - Process for the operation of a heat engine with a gaseous medium - Google Patents

Abstract

A very efficiently functioning process for the operation of a heat engine with a gaseous medium functions entirely in the superheated range in a cycle which comprises a large isobaric first section, an adiabatic or isothermic second section, a second large isobaric section and a fourth section, which also runs adiabatically or isothermally, the pressure differential between the two isobars being comparatively small and the temperature differences comparatively large, and the work obtained due to the volume expansion being converted isobarically into admission work in the heat engine.

Description

description

The invention relates to a method for operating a heat engine with a gaseous medium.

Steam engine Internal combustion piston engines, gas turbines and other heat engines work on the principle; that a medium is supplied with heat and this medium in the heat engine is relaxed to a lower temperature. The temperature gradient corresponds to the mechanical work gained. Remaining residual heat is dissipated. What these machines have in common is that the waste heat has a lower temperature level than the heat supplied and either not at all or only to a very small extent Part is fed back into the process.

The invention is based on the object of a method of operation to create a heat engine with a gaseous medium, through that the Waste heat losses minimized, the energy contained in the waste heat for operation the heat engine can be exploited and its efficiency is increased.

To solve this problem it is proposed that superheated fresh gas with a volume 1, a pressure P1 and a temperature T1 initially in a heat exchanger largely isobaric due to the countercurrent exhaust gas from the heat engine while increasing its volume to a value V2 to an intermediate temperature T2.

and then continues to be largely isobaric through the addition of external energy reheated to a final temperature T3 with an increase in volume to a value V3 is that the gas is then introduced into the heat engine and there converts the work gained by the volume expansion isobarically into inflow work and then expanded to an overheated exhaust gas state V4, P4, T4, that this exhaust gas then outside the heat engine and into the heat exchanger largely isobaric while reducing its volume to a value V5 in countercurrent to the fresh gas first until an intermediate temperature T5 is reached and then by after-cooling - as well as being largely isobaric until it is still overheated Temperature value T6 and a volume V6 heat is withdrawn and that the gas on it compressed into the fresh gas state V1, P1, T1 and then back into the heat exchanger is pushed.

In individual cases it can be advantageous that the after-cooling of the gas following its compression and before its countercurrent heating is made.

The core idea of the solution according to the invention is thus that most of the expected work from the expansion of the gas and only a little Part of its relaxation is obtained and in this way that contained in the exhaust gas Energy can be used optimally when using a direct current compressor and a direct current heat engine can increase the volume of the gas from V4 to V5 can be reduced without mechanical work.

An embodiment of the method according to the invention is given below explained with reference to the attached Molier h, p diagram.

The cycle runs through the diagram in a clockwise direction. It is important that the gaseous medium at no time a condensation area runs through, so remains in the overheated area at all times.

Furthermore, it is important that the still explained in detail Pressure differences comparatively small and the temperature differences also mentioned should be comparatively large.

The parameters of the state of the gas given below at the various Points in the diagram relate to a calculation example in which the working gas Hydrogen was used. It thus follows that the following state variables with regard to their absolute values are only to be considered as an example.

At the point of the diagram, fresh gas is in a state of V1 = 1872 dm3, P1- = 4.2 bar, T1 = 1910K before.

This fresh gas is on the diagram section 1 - 2 in a countercurrent heat exchanger isobarically converted into the state V2 = 2754 dm3, P2 = 4.2 bar, T2 = 2810K.

This is followed by isobaric reheating according to the diagram 2 - 3 to a glass condition V3 = 2806 dm3, P3 = 4.2 bar, T3 = 286.30K.

With this state, the gas is fed into the heat engine and there, according to the performance of the isobaric inflow work, approximately isothermal or adiabatic relaxed to the state V4 = 3757 dem3, T4 = 3.1 bar, T4 = 2830K. That the heat engine Exhaust gas leaving this state is now passed into the countercurrent heat exchanger and gives its heat to the opposite in accordance with the diagram section 4-5 flowing fresh gas (route 1 - 2). To enable this heat transfer; the exhaust gas must have a higher temperature at every point in the heat exchanger as the fresh gas. To achieve this, the aforementioned post-heating is along the diagram section 2 - 3 provided.

The exhaust gas leaves the heat exchanger with a state -V5 = 2562 dm3, P5 = 3.1 bar, T5 = 1930K. In terms of what is required for heat transfer Temperature difference and the subsequent compression of the gas as well as the resulting temperature increase of 2.50K is the exhaust gas before it enters initially set the compressor to a state V6 = 2503 dm3, P6 = 3.1 bar ,. T6 = 188.5 ° K post-cooled. In a compressor there is then a largely adiabatic or isothermal compression to the fresh gas state V1, P1, T1 instead.

Finally, it should be noted that both the post-cooling and the Post-heating of the gas not only as shown before point 6 and before point 3 can take place, but that both can take place either in the range 1 - 3 or 4 - 6 can be inserted.

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Claims (7)

Method for operating a heat engine with a gaseous one Medium A n p r ü c h e Method for operating a heat engine with a gaseous medium, characterized in that superheated fresh gas with a Volume V1, a pressure P1 and a temperature T1 initially in a heat exchanger largely isobaric due to the countercurrent exhaust gas from the heat engine while increasing its volume to a value V2 to an intermediate temperature T2 and then by supplying external energy continues to be largely isobaric to a final temperature T3 is reheated to a value V3 with an increase in volume, that the gas is then introduced into the heat engine and there by the volume expansion The work gained is converted isobarically into inflow work and then transferred to an overheated one Exhaust gas state V4, P4, T4 is relaxed, that this exhaust gas then outside the heat engine and largely isobaric in the heat exchanger while reducing its volume a value V5 in countercurrent to the fresh gas initially until an intermediate temperature is reached T5 and then by post-cooling and still largely isobaric up to one still overheated temperature value T6 and a volume V6 heat is withdrawn and that the gas is then compressed into the fresh gas state V1, Pl, T1 and then is pushed back into the heat exchanger. 2. The method according to claim 1, characterized in that the gas in the heat engine almost adiabatically following the isobaric inflow work is relaxed. 3. Method according to claim 1, characterized in that the gas in the heat engine almost isothermally following the isobaric inflow work is relaxed. 4. The method according to any one of claims 1 to 3, characterized by an initially approximately adiabatic compression of the gas to the fresh gas state and a subsequent, if possible, isobaric extension into the heat exchanger. 5. The method according to any one of claims 1 to 3, characterized by an initially approximately isothermal Compression of the gas on the Fresh gas state and a subsequent, if possible, isobaric expulsion into the heat exchanger. 6 ,. Method according to one of Claims 1 to 5, characterized in that that the post-cooling of the gas following its compression and before its im Countercurrent heating is carried out. 7. The method according to claim 1, characterized in that the movements the compressing and the heat engine are synchronously coupled in such a phase-shifted manner be that with the start of the expansion work of the compressor, the inflow work of Heat engine starts.