WO1992018815A1

WO1992018815A1 - Method and device for tapping and converting thermal energy

Info

Publication number: WO1992018815A1
Application number: PCT/FR1992/000325
Authority: WO
Inventors: Richard Pulvar
Original assignee: Richard Pulvar
Priority date: 1991-04-12
Filing date: 1992-04-13
Publication date: 1992-10-29
Also published as: FR2675245A1; AU1685992A

Abstract

A device for tapping and converting thermal energy. A method and a device are provided for tapping thermal energy from any source or deposit regardless of its temperature, wherein a refrigerating device for absorbing calories from without is combined with a motor device for converting the calories into work, and a device for recycling the calories through electromagnetic radiation. Since the device requires no external cold source, its thermodynamic efficiency is therefore 1, and calories can be tapped even from low-temperature deposits. Said device is designed particularly for tapping latent ocean energy and other energy sources with a thermodynamic efficiency of 1.

Description

PROCESS AND DEVICE FOR OPERATING AND

TRANSFORMATION OF THERMAL ENERGY

The present invention relates to the exploitation and transformation of thermal energy from any source or any deposit, whatever its temperature level.

The invention relates both to the method and to the devices. Four immediate fields of exploitation arise.

1 - Exploitation and transformation of the latent energy contained in any deposit, such as the considerable latent caloric energy contained in the water of the oceans, lakes and rivers.

2 - Exploitation of so-called diluted energy, such as solar energy with a theoretical thermodynamic efficiency close to unity.

3 - Exploitation of so-called degraded energy, such as the calories given up at the cold source by the cooling circuits of thermal machines and installations, whether conventional or nuclear. This dissipated energy usually represents the largest part of the energy consumed by these installations.

4 - Realization of devices integrating from the start the recovery of the calories given up to the cold source, in order to design machines and thermal installations whose theoretical thermodynamic efficiency would be close to unity.

Carnot's principle indicates that a machine operating on a thermodynamic cycle necessarily yields energy to a cold source. This energy transferred to the cold source defines the thermodynamic efficiency of the installation, and in most cases, between 60 and 101 of the energy supplied to an installation goes into pure loss thus to the cold source.

Carnot's principle, on the other hand, indicates that heat spontaneously passes from a warm environment to a cold environment. Conversely, the passage of calories from a cold environment to a warm environment (refrigerant cycle) requires the consumption of work provided by an external device. In the case of thermal exploitation of this energy, the operation can be profitable, such as heat pumps. In the case where this energy must be exploited in a form other than thermal energy, the work necessary for the forced circulation of calories from the cold source to the hot source at the same absolute value with the output close than that which can be developed by those calories. It was therefore impossible to recover the energy transferred to the cold source in a profitable manner. On the other hand the latent caloric energy contained in many deposits could not be exploited for lack of a cold source allowing kinetics of calories. In the case of thermal energy from the seas, one trick was to use the temperature difference between surface water and deep water. The problem is thus brought back to a classic thermodynamic cycle of very low efficiency

(about 0.071), so there is not really exploitation of the latent energy.

In existing thermodynamic machines operating according to a cycle whether it is open or closed, the various exchanges of calories are essentially carried out by conduction, using a fluid traversing the cycle. In conduction, the transfer of calories actually corresponds to the transfer of kinetic energy of the particles. There is a slowing down of the particles of the hot medium and reduction of their kinetic energy, for the benefit of an acceleration of the particles of the cold medium and increase of their kinetic energy. We understand that a particle of a given speed cannot accelerate a particle of higher speed. The transfer can therefore take place naturally only from a particle of given speed to a particle of Lower speed, from hot to cold. This is the essential condition of all existing thermodynamic machines.

The process which is the subject of the invention is characterized in that it overcomes the condition of the single passage of calories from hot to cold. The process which is the subject of the invention is characterized by the fact that it operates by the combination of a direct thermodynamic cycle (motor) and an inverted thermodynamic cycle

(refrigerant). The principle consists in extracting the caloric energy from any source or any deposit using the refrigerant cycle, and to exploit it using the engine cycle. The difficulty consists in "revalorizing" the calories thus drawn, that is to say bringing them to a temperature level such that they can be exploited by the engine cycle.

The method obj and the invention is characterized in that the revalorization of calories is done by radiation and not by conduction in order to get rid of the conditions of kinetic energy transfer.

The device which is the subject of the invention is characterized in that it comprises a "exchanger-concentrator" of radiation; In this concentrator exchanger the calories are brought by conduction to an emitter (which can constitute the cold source of a thermodynamic machine). The transmitter radiates in an enclosure or has been evacuated. The emitted electromagnetic radiation is then concentrated either:

- using an optical system in the manner of concentrators of solar radiation.

- using a thermal diode system allowing the accumulation of radiation in the enclosure. The concentrated heat flux is absorbed by a receiver (which can constitute the hot source of a thermodynamic machine). The absorption of this concentrated flux causes the receiver to have a temperature higher than that of the transmitter. The calories are then removed by conduction.

The device which is the subject of the invention is characterized in that it allows a transfer of calories from a given temperature level to a higher temperature level, and this without the need for work from an external device.

According to one provision of the invention, the calories given up at the cold source of the engine cycle are revalued in the same way. The system therefore does not require to operate the existence of a cold source proper or it would transfer energy to the external system.

It follows that the process and the devices that are the subject of the invention are characterized in that, not requiring a cold source, they allow the exploitation of any source or source of caloric energy whatever its temperature level. . On the other hand not yielding any calories to the external system, the theoretical thermodynamic yield is equal to 1. All the calories drawn being exploited. - Figure 1 is shown in a clapeyron diagram

a possible example of a combination of engine and coolant cycles.

- Figure 2 is the diagram of an installation operating according to the cycle of Figure 1.

- Figures 3 and 4 show possible examples of optical concentrators.

- Figure 5 shows the block diagram of a concentrator with thermal diode effect.

- Figure 6 shows an example of a thermal diode effect concentrator.

- Figure 7 shows an example of installation operating according to the cycle of Figure 1 applied to the exploitation of the latent energy of a fluid deposit.

- Figure 8 shows an example of installation operating according to the cycle of Figure 1 applied to the exploitation of solar energy.

- Figure 9 shows an example of installation operating according to the cycle of Figure 1 applied to the exploitation of degraded energy of the cooling circuits.

- Figures 10, 11, 12 show recovery devices integrated with energy production devices. 1st Application: exploitation of latent energy.

Figure 1 shows the cycle of one of the possible solutions. It is a closed phase (gas) system in which the engine and refrigerant cycles are combined so as to be traversed by the same fluid. The advantage of this combination is both mechanical and thermodynamic. The compression work of the refrigerant cycle and the engine cycle is done continuously on the same isentropic curve. Similarly, the calories from the refrigerant cycle and the cold source from the engine cycle are transferred continuously on the same isobaric curve. All of the calories transferred are recycled. The thermodynamic efficiency of the system is therefore 1. This combined cycle allows the realization of a simple installation according to the diagram in FIG. 2 which constitutes one of the possible solutions.

Calories are taken from the deposit by an absorber A in which a fluid (freon for example) circulates at a temperature lower than that of the deposit. The exchange is therefore made by conduction. The fluid is then compressed by the compressor C. It receives the infrared radiation concentrated in the receiver R of the exchanger-concentrator EC; A

first expansion takes place in the Tl turbine. At the emitter E of the exchanger EC, the fluid yields to the nearest yield, an amount of calories equivalent to that which it had absorbed in R. A second expansion takes place in the turbine T2, before entering the absorber A for a new cycle in accordance with Figure 1 the cycle breaks down as follows:

- from 1 to 2 adiabatic compression in compressor C

- from 2 to 3 isobaric reheating in the R receptor

- from 3 to 4 adiabatic expansion in the turbine T1

- from 4 to 5 isobaric cooling in the transmitter E

- from 5 to 6 adiabatic expansion in the T2 turbine

- from 6 to 1 isobaric heating in absorber A

The balance of powers is established as follows: Let Cp be the specific heat at constant fluid pressure

considered.

Cv the specific heat at constant volume of the fluid

considered.

Is

Let rp1 be the outlet pressure / inlet pressure ratio of C rp2 the inlet pressure / outlet pressure ratio of T1 rp3 the inlet pressure / outlet pressure ratio of T2 The logical operating condition is

rp1 = rp 2 × rP3 so as to form a cycle

Motor cycle

Power absorbed at the receiver:

Power ceded to the transmitter:

Power developed by the engine cycle

Refrigerant cycle

Power absorbed at the exchanger:

Power ceded to the transmitter:

Power consumed by the refrigeration cycle

Combined cycle

Total power transferred to the transmitter

Usable power

e developed

The balance of the powers of the compressor and the turbines produces an excess which can be used in a U receiving machine (generator, pump, PTO or other ...)

The useful power corresponds to the caloric power taken from the deposit. This balance corresponds to the theoretical power available and does not take into account the different yields.

The architecture shown is the simplest, it offers the coupling of all the motor or receiver members on the same shaft. It is however possible to operate them separately or linked together by speed reducing or multiplying members. In the case where the deposit is a mass of eσu a pump as shown in Figure 7 could be coupled to the motor shaft.

The revalorization of calories is done thanks to the exchanger-concentrator. All typeide optical concentrators such as those used for solar energy can be applied here.

The difficulty consists in ensuring that all of the radiation emitted is reflected towards the receiver, and that there is indeed concentration. In addition, the different reflections are not without loss, it is better to reduce the number.

FIG. 3 represents, according to a provision of the invention, one of the possible solutions of optical concentration. It is a compound anicone set. The emitter E radiates in a parabola P which distributes the radiation in a compound parabolic concentrator (CP.C.) on one or more stages, the last being closed by a reflector in developing circle (DC). The concentration factor C is equal to the ratio of the emitter E and the receiver R.

FIG. 4 represents, according to a provision of the invention, a type of concentrator which can be used.

It is an airtight enclosure in which a vacuum has been created, and or radiates an emitter E towards a receiver R.

The reflective interior surface constitutes the optical system itself. The concentrator curve is a function of the normally equal diameters of the emitter and the receiver, and the distance between these 2 foci. They are constructed according to the wire method similar to the construction of an ellipse, and constitute a so-called ideal anicone concentrator which transmits the totality of the radiation emitted from E towards a focal point of equivalent diameter in R. The receiver R consists of a first envelope with a diameter greater than the diameter of E so that there is intersection between the radii from E and the surface of the envelope. This first envelope is made of transparent infrared materials such as chalcogenide glass.

The refractive index of this envelope is such that the refracted rays are concentrated towards the interior envelope which constitutes the receiver itself. The concentration ratio C is equal to the ratio of the diameters of the emitter and the receiver.

Part of the radiation absorbed in R is re-emitted in the direction of E, and in the case where the emitting and receiving surfaces are not of the same nature, it occurs with the phenomenon of concentration by thermal diode effect as described in the type of next concentrator.

Figure 5 shows the block diagram of the concentrator with thermal diode effect.

According to the invention, the principle consists in using the absorption and reflexion characteristics of the emitting and receiving surfaces to cause in the enclosure an effect of concentration of the heat flux. Let us consider the emitter E, on one side it is in contact with the fluid which is at the temperature TF ₁ and on the other side II radiates in the enclosure. It receives from the receiver radiation of a flow son _c its thermal equilibrium is thus established.

- The fluid communicates the temperature TE by conduction

- Radiated flux

= stephan constant

total emission factor at TE temperature

- Reflected flow

= total reflection factor at temperature TE

- Total flow emitted ∅ _E = ∅ _R + ∅ _RFE

- Absorbed power of the fluid = P _FE

- Absorbed power of radiation ∅ _c from R

P _AE = ∅ _AE S _E

with S _E = surface of the transmitter.

- Total emitted power P _E = ∅ _E SE

at equilibrium we have P _E + P _FE + P _AE = O

Let us consider the receiver R, it receives from the transmitter E the total flux ∅ _{E from} which it absorbs a part ∅ _A , and reflects a part ∅ _RFA . The absorbed flux ∅ _A causes the temperature T _A and a retransmission ∅ _RE towards the transmitter.

- Total flow received ∅ _E

- Absorbed flux ∅ _A = α _A ∅ _E

with α _A = total absorption factor at temperature T _A

Reflected flow

with

= total reflection factor at temperature T _A

Reissued flow ∅ _RE = δε _A T _A ⁴

with ε _A = total emission factor at temperature T _A Power transmitted to the fluid P FA

Power consumption P _A = ∅ _A S _A1

with S _A1 = entry surface of R = S _E

Power reduction P _RE = ∅ _RE S _A1

at equilibrium or a P _A + P _FA + P _RE = O

We identify the power P _FA transmitted by the receiver to the action of a flux ∅ _U which would be transmitted by the surface S _A2 of the receiver output.

so we have ∅ _A = ∅ _RE + ∅ _U ∅ _RE = ∅ _A - ∅ _U

we arrive after calculations at the expression

we obviously have the maximum temperature for ∅ _U = O which

leads to expression

from which we conclude:

- For a perfectly identical transmitter and receiver, there is no concentration, so it is necessary to play on the characteristics of the emitting and receiving surfaces.

more

- The surface S _E must be, the emitter and the least absorbent possible ε _E high α _E low.

- The surface S _A1 must be the most absorbent and the least emitting possible α _A high ε _A low.

In the absence of any use of power at S _A2 (∅ _U = O) if ε _A tends towards O, T _A tends towards + ∞

there is therefore a natural circulation of calories from a temperature transmitter T _E to a temperature receiver T _A > T _E

Independence of the heat flow used in the installation and which passes through the exchanger, a flux is constantly exchanged

of between E and R. It is largely reflected on the surface E

(high) and therefore does not significantly modify the temperature T _E of E. It is largely absorbed in R and contributes to raising the temperature T _A of R before being re-emitted at high temperature (ε _A low).

Of course, as the useful power at the output of R increases, the temperature T _A will drop. We define β as being the ratio of the useful flux on the radiated flux.

As an example, consider an emitting surface α _E = 0.25 and ε _E = 0.9

a receiving surface

α _A = 0.98 and ε _A = 0.19

the maximum concentration factor (∅ _U = 0) would be

By taking β = 0.5 ∅ _U = 0.5 ∅ _R we have

Figure 6 shows a diode effect concentrator. It essentially consists of two concentric tubes:

the emitter E and the receiver R separated by a very small space in which the vacuum is created. Outside of E in a cabrifuged enclosure circulates the fluid which yields its calories to E at the temperature T _F1 inside R circulates the fluid which receives the calories from R at the temperature T _F2 . The inner diameters of E and the outer diameters of R being very close, we can consider S _E = S _A1 . The exchange surface S _A2 is a function of the concentration factor chosen so that ∅ _U × S _A2 = PE

FIG. 7 represents an example of installation according to the invention, operating according to the cycle defined in FIG. 1 applied to the exploitation of the latent energy of a deposit

fluid. A pump allows the circulation of fluid from the deposit in an exchanger.

2nd Application: Exploitation of solar energy.

The system as shown in Figure 8 works according to the cycle defined in figure 1. The absorber consists of the insolator or the hearth of a conventional solar installation. In addition to the high thermodynamic efficiency, the method has the advantage of allowing the use of a sensor at low temperature, so as to limit losses by retransmission of infrared, and allowing easy capture of direct incident infrared. or diffuse.

3rd Application: Heat recovery by the cooling circuits of machines and thermal installations.

The system as shown in FIG. 9 operates according to the cycle defined in FIG. 1. The absorber A consists of an exchanger in which the cooling fluid of the machine or of the installation circulates. Such a correctly dimensioned system makes it possible to recover, in addition to the calories transferred to the cold source, part of the latent energy contained in the fluid itself.

4th Application: Realization of devices integrating from the start the recovery of calories from the cold source.

The systems shown in Figures 10 and 11 operate according to the cycle defined in Figure 1. This is the case of operation using a closed circuit such as a nuclear power plant. The absorber consists of the exchanger between the primary and secondary circuits (Figure 10) or between the secondary and tertiary circuits (Figure 11).

The system shown in Figure 12 works according to the cycle defined in Figure 1. It concerns machines or installations using an open cycle, such as all combustion machines (engines, boilers, etc.) an additional compressor and turbine are required to the combustion gas circuit.

The absorber consists of an exchanger preferably located downstream of the turbine of the combustion gas circuit. The architecture shown proposes the coupling of all the transmitting or receiving members on the same shaft, but they can either be separated or linked together by speed reducing or multiplying members.

Claims

1 / Process for exploiting and transforming the thermal energy of a deposit or any source characcterized by the use of a special thermodynamic cycle. 2 / A method according to claim 1 characterized in that the special cycle is a cycle resulting from the combination of a normal engine cycle (Brayton cycle) and an inverted cycle (refrigerant cycle) so that:

a - The compression phases of the engine cycle and the reverse cycle (refrigerant) are done during the same phase of the combined cycle. b - The heat transfer phases of the engine cycle and the reverse cycle (refrigerant) take place during the same phase of the combined cycle.

3 / A method according to claims 1 and 2 characterized in that the successive phases of the cycle are: 1 to 2 Adiabatic compression

2 to 3 Isobaric heating

3 to 4 Adiabatic relaxation

4 to 5 Isobaric cooling

5 to 6 Adiabatic relaxation

6 to 1 Isobaric heating

The combined cycle therefore includes S sources including 2 sources of absorption of calories from the outside, 1 source of transfer of calories to the outside.

4 / A method according to claims 1, 2, 3, characterized in that the totality of the calories supplied to the system during the isobaric heating from 2 to 3 comes from the totality of the calories yielded by the system during the isobaric cooling from 4 to 5 .

There is therefore "recycling" of all the calories transferred by the system to the outside, and equality of the quantities of heat exchanged from 2 to 3 and from 4 to 5.

5 / A method according to claims 2, 3, 4 characterized in that the calories released by the system being fully recycled, the theoretical thermodynamic yield of the process is equal to 1. 6 / A method according to claims 2, 3, 4 characterized in that the heat absorption source constituted by the isobaric heating phase from 2 to 3, and the heat transfer source constituted by the isobaric cooling phase from 4 to 5 exchanging all of their calories exclusively, there remains only one real source of heat exchanging with the outside, that of isobaric heating from 6 to 1.

7 / A method according to claims 2, 3, 4, 6 characterized in that requiring only one source of heat exchange with the outside, that of absorption of calories during the isobaric heating phase from 6 to 1, it allows the exploitation of thermal energy from any source or deposit, in particular the thermal energy of lakes, rivers and oceans, and this without the need to search for a cooler source than the deposit for give up calories. 8 / A method according to claims 4, 5 characterized in that the recycling of calories takes place by radiation of energy by a surface in a vacuum chamber, and absorption of this radiation by another surface.

9 / A method according to claims 4, 5, 8 characterized by a passage of calories from a surface of a given temperature to a surface of higher temperature using an optical system of radiation concentration.

10 / A method according to claims 4, 5, 8 characterized by a passage of calories from a surface of a given temperature to a surface of higher temperature using a thermal diode system.

11 / A method according to claims 4, 5, 8, 10 characterized in that the thermal diode consists of 2 surfaces, a transmitter, a receiver which radiate through a vacuum enclosure.

12 / A method according to claims 4, 5, 8, 10, 11 characterized in that the two surfaces are treated so as to obtain: - For the emitting surface, a low absorption coefficient and a high emission coefficient.

- For the receiving surface, a high absorption coefficient, and a low emission coefficient,

compared to their reciprocal radiations.

13 / Device for exploiting and transforming the thermal energy of a deposit or any source characterized in that its operation is governed by the method according to claim 1.

14 / Apparatus according to claim 13 characterized in that it comprises a heat exchanger-concentrator, consisting of a sealed enclosure in which the vacuum has been made, and in which are installed, an exchanger-emitter and an exchanger-receiver.

This exchanger-concentrator allows the circulation of calories from the transmitter at a given temperature T _E to the receiver at a temperature T _A such that T _A > T _E.

15 / Device according to claim 14 characterized in that the hermetic vacuum enclosure constitutes an optical system concentrating radiation.

16 / Apparatus according to claims 14, 15 characterized in that the receiver is constituted by a tubular casing made of material transparent to infrared radiation concentric with another tubular casing of smaller diameter made of material absorbing infra-red radiation.

17 / Apparatus according to claim 14 characterized in that. exchanger-concentrator constitutes a thermal diode in which:

- The emitting surface has a low absorption coefficient and a high emission coefficient.

- The receiving surface has a high absorption coefficient and a low emission coefficient,

compared to their reciprocal radiation. 18 / Apparatus according to claim 13 characterized in that the calories are drawn from the source or from the deposit by an absorber made of a material which is a good conductor of heat inside which the heat transfer fluid circulates at a temperature lower than that of the source or of the deposit, and this, during the refrigerating part of the thermodynamic cycle carried out by the fluid.

19 / Device according to claims 13, 14, 17, 18 characterized in that it comprises:

a - An absorber according to claim 18.

b - A compressor with one or more stages.

c - An exchanger-concentrator.

d - A first floor or first group of floors. turbines.

e - A second stage or second group of turbine stages.

f - A circuit for circulation of the heat transfer fluid.

g - Circulation of the fluid in the exchanger-concentrator between the first and second turbine stages or between the first and second group of turbines.

20 / Apparatus according to claims 13 and 19 characterized in that the different motor and receiver members are directly connected by the same shaft.

21 / Device according to claims 13 and 19 characterized in that the various motor and receiver members are connected to each other by means of speed reducing or multiplying members.

22 / Device according to claims 13 and 19 characterized in that the absorber constitutes the insulator or the hearth of a conventional solar installation.

23 / Device according to claims 13 and 19 characterized in that the absorber consists of an exchanger in which circulates on one side the fluid from the source or deposit, on the other the heat transfer fluid of the device. 24 / Device according to claims 13 and 19 characterized in that the caloric source consists of the gases of a combustion machine using an open cycle.

25 / Apparatus according to claims 13, 19, 24 characterized in that the combustion machine is an integral part of the device which has for this an additional compressor and turbine.