DE2812429A1 - Heat engine using air heat - comprises two cylinder machine giving adiabatic expansion followed by isothermal compression - Google Patents

Abstract

The heat engine uses air heat, comprising a two-cylinder piston machine in which the air undergoes a three-stage quasi-open process - adiabatic expansion, followed by isothermal compression and isobar heat absorption. To remove the waste heat released on isothermal compression a heat pump is inserted. This transfers this heat to the cold air leaving the machine, including the compression heat of the heat pump with a relatively small temp. drop.

Description

Heat engine for the use of air heat

The present heat engine converts the in the atmospheric Air stored solar or geothermal heat directly, d. H. without use a heat exchanger, into mechanical work. It is all the cheaper for the efficiency of the heat engine, the higher the temperature of the ambient air is. The air supplied to the machine leaves it at a relatively low temperature at ambient pressure. The difference in heat between the incoming and outgoing air can be converted into technical work (according to the mechanical heat equivalent).

Because the heat content of air at ambient pressure and temperature is relative is small, relatively large amounts of air have to be implemented in order to achieve high performance will. This requires relatively large cylinder volumes. Such a heat engine is therefore predominantly in static construction and operated enormously by large power plants (power plants) have to.

From the amount of air supplied to the machine at 1 m3 per second at 300 K. (= 270C) Air temperature can, for example, Practically (after deducting all losses) about 10 KW of mechanical power can still be obtained. With the work submission At the same time, cold air is released into the environment, which can also be used, z. ß. in cold stores to keep food fresh, etc.

There is practically unlimited amounts of air everywhere on earth sufficient temperature and at all times (day and night) is available and the Air leaves the machine in an environmentally friendly way, it can be called the "ideal power machine." of the future ".

With the mechanical energy obtained from it, for example (via generators) electrical energy and from it (through electrolysis) hydrogen gas be won. Hydrogen gas can still be used to produce powerful and operate absolutely environmentally friendly internal combustion engines (e.g. car engines). In this way, the entire energy supply could be obtained from the previous fuels Make (fossil and nuclear) completely independent and secure for all future.

Description The air runs through a three-part, quasi-open, Heat engine process in the order: adiabatic relaxation -> isothermal Compression -> isobaric heat absorption 0 The isothermal thickening The heat of compression qO to be dissipated is achieved by means of a heat pump (WP), which this heat (including the heat generated by the work of compression k am Compressor Kp of the heat pump arises) at a relatively small temperature gradient the discharged i subcooled (used) air at ambient pressure neither supplies Because the work required to operate the heat pump Wk Practical can be measured significantly smaller (theoretically 's vanishing small) than the mechanical work W, which is free rotating in the heat engine process, remains one positive differential work We left, which can be dissipated to the outside and used (W - Wk = + W) 0 Thus it is possible to bypass the 2nd law of thermodynamics, without violating the law of entropy.

According to Fig. 1, the eccentric arrives after opening valve V1 and starting disc (or crankshaft) E from the outside (by means of a starter motor) the air into the expansion cylinder Z1. Their amount should be V1 m3 and the temperature T1 ° C. Starting from this state 1 (P, v diagram and T, s diagram in Fig. 2 and 3) the air becomes adiabatic to one so low pressure -relaxed that it cools down to the desired temperature T2. Work must first be done against the higher ambient pressure Pu, which is represented by the area 1-a-20 Now the air of the must now lower Pressure P2 are brought to ambient pressure. To do this, you first transport the Air after opening valve V2 and corresponding piston displacements from the cylinder Z1 into cylinder Z2 (Fig. 1).

After closing the valve V2 compresses the gas BEZW. the air in cylinder Z2 starting from 2 isothermally to 3, whereby the heat of compression qO at the constant temperature T2 with theoretically vanishingly small (in practice "retatively" small) temperature gradient reversible (via the evaporator Vpf and condenser Ko of the heat pump) to the output of the compression cylinder Z2 with the temperature T3 and the pressure P3 = Pu is released to the environment (the valve V3 is a pressure relief valve and opens when ambient pressure is reached in cylinder Z2).

The higher external pressure P u on cylinder Z2 does a job, represented by area 3-a-2. Thus the difference represents area 1-2-3 represents the work W gained as a whole and at the same time the highest possible. the Used cold air expelled at the outlet with a temperature T3> T> Tß u. the ambient pressure p3 = pu now increases independently, d. H.

without an outer work wall, heat from the ambient air up to the Ambient temperature Tu = T1 is reached again. The initial state Pu, Tu (des via the atmosphere of the open cycle) is thus restored.

The maximum amount of work that can be gained from the warm air. atmospheric air results from the three-part engine process used (without deducting the workload for the heat pump) m = mass of the working substance c = specific heat of the working substance at constant pressure p Tu = T1 = temperature of the atmospheric air T2 = temperature of the air after expansion.

Using an example, it should be shown that even with appropriate Consideration of the existing losses from atmospheric air mechanical work is to be won.

Example How big is a) the theoretical, b) the practically obtainable Power from atmospheric air if 1 m3 of air per second of the heat engine and the following temperatures are used as a basis: Inlet temperature in the Cylinder Z1: Tu = T1 = 300 K (= 270C) Relaxation temperature in cylinder Z2: T2 = 170 K (= -1030C).

The temperature gradient to be created with the operation of the heat pump be chosen as T2 - T1 = (180 - 160) K = 20 ° C (Fig. 3).

Solution a) Theoretically (maximum) achievable power results from the above equation and the following underlying data for air: m = 1.225 Kg / s (> 1 m3 air per second), c = 1.004 KJ / Kg K (= specific heat for Louft p at 1 bar and 0 C) = 1.225. 1.004. 170 (+ - 1 - 0700) [KJ / s3 170 - = 210 (1.77 - 1 - ln 1.77) = 210 (0.77 - 0.57) = 210. 0.2 = 42 KJ / s = 42 KW = 57 PS b) The practically (minimal) achievable power is calculated as follows: Based on the theoretical area ratio (Fig. 3) With an existing loss of working area (due to polytropic operating mode and additional mechanical losses) for q of 50%, a real (indexed) working area ratio of W 'q' 0.5 is obtained. 3.25 = 1.625 ie after subtracting Wq qa 1 1 the mechanical work to be expended on the heat pump, for example 1 KWh, is now still (1.625 - 1) KWh = 0.625 KWh effectively available on the output shaft.

From the originally theoretically available useful heat of 3.25 KWh can practically only 9.625 = 0.192 19% 3.25 of the under a) calculated theoretical value can be obtained, i.e. Wmin = 0.19 W max Wmax = 0.19. 42 KJ / s = 8 KJ / s = 8 KW = 11 PS.

This shows that one can get out of the warmth of atmospheric Air can gain mechanical work.

L e r s e i t e

Claims (2)

Heat engine for the use of air heat, thereby characterized in that the air by means of a two-cylinder piston engine three-part, quasi-open engine process in the sequence: adiabatic Expansion -risothermal compression isobaric heat absorption, whereby for A heat pump eliminates the waste heat released during isothermal compression is used that this heat (including the compression heat of the heat pump) with a practically relatively small (theoretically "vanishingly small) temperature gradient to which the cold air leaving the machine is released. 2. Heat engine for the use of air heat as described and signed (further detailed claims reserved).