Installation and method for the production of cold and/or heat

Abstract

An installation for the production of cold and/or heat has a driving and a receiving machine. The driving machine has means for circulating a working fluid G.sub.M, an evaporator E.sub.M, at least one transfer cylinder CT.sub.M that contains a transfer liquid LT in a lower part and the working fluid G.sub.M liquid and/or vapor form above the transfer liquid, a condenser C.sub.M, at least one device BS.sub.M for separating the liquid and vapor phases of the working fluid G.sub.M, and a device for compressing the working fluid G.sub.M to the liquid state. The receiving machine has means for circulating a working fluid G.sub.R, a condenser C.sub.R, at least one device BS.sub.R for compressing or expanding and separating the liquid and vapor phases of the working fluid G.sub.R, optionally a pressure reducer D.sub.R, an evaporator E.sub.R, and at least one transfer cylinder CT.sub.R that contains the transfer liquid LT in a lower portion and the working fluid G.sub.R in liquid and/or vapor form above the transfer liquid; the transfer cylinders CT.sub.R and CT.sub.M are connected by at least one pipe that can be blocked by actuators and in which only the transfer liquid LT can circulate.

Claims

1. A trithermal or quadrithermal installation for the production of cold and/or heat, comprising a driving machine and a receiving machine, wherein: a) the driving machine comprises pipes and actuators for causing a working fluid to circulate and also, in the order of circulation of said working fluid: an evaporator; at least one transfer cylinder that contains a transfer liquid in a lower portion and the working fluid in liquid and/or vapor form above the transfer liquid; a condenser; at least one device for separating the liquid and vapor phases of the working fluid; a device for pressurizing the working fluid in the liquid state; b) the receiving machine comprises pipes and actuators for causing a working fluid to circulate and also, in the order of circulation of said working fluid: a condenser; at least one device for pressurizing or expanding and separating the liquid and vapor phases of the working fluid; an evaporator; at least one transfer cylinder that contains the transfer liquid in a lower portion and the working fluid in liquid and/or vapor form above the transfer liquid; and c) the transfer cylinders and are connected by at least one pipe that may be blocked by actuators and in which only the transfer liquid may circulate.

2. An installation according to claim 1, wherein any working fluid, designated as and the transfer liquid are chosen so that the working fluid is weakly soluble, preferably insoluble, in the transfer liquid, the working fluid does not react with the transfer liquid, and the working fluid in the liquid state is less dense than the transfer liquid.

3. An installation according to claim 2, wherein the transfer liquid and the working fluid are isolated from each other by isolating means that do not prevent the exchange of work between the transfer cylinders and.

4. An installation according to claim 3, wherein said isolating means includes a flexible membrane disposed between the working fluid and the transfer liquid or a float that has an intermediate density between that of the working fluid in the liquid state and that of the transfer liquid.

5. An installation according to claim 1, wherein said driving machine has a single transfer cylinder and said receiving machine has a single transfer cylinder.

6. An installation according to claim 1, wherein said driving machine has two transfer cylinders and said receiving machine has two transfer cylinder.

7. An installation according to claim 6, wherein said installation further comprises two separate pressurization devices for the driving machine and two separate pressurization devices for the receiving machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention can be best understood through the following description and accompanying drawings, wherein:

(2) FIGS. 1a and 1b are theoretical temperature diagrams, in accordance with one embodiment;

(3) FIG. 2a-2c each show a transfer cylinder, in accordance with one embodiment;

(4) FIG. 3 is a plot of liquid/vapor equilibrium curves, in accordance with one embodiment;

(5) FIG. 4 shows a transfer cylinder, in accordance with one embodiment:

(6) FIG. 5 shows an installation with a single CT.sub.M/CT.sub.R component, in accordance with one embodiment;

(7) FIGS. 6a and 6b are Mollier diagrams plotting the logarithm LnP of the pressure as a function of h, in accordance with one embodiment;

(8) FIGS. 6c and 6d are Clausius-Clapeyron diagrams which plot LnP as a function of (1/T), in accordance with one embodiment;

(9) FIG. 7 shows an installation with two elements, each with a transfer cylinder CT.sub.M and a transfer cylinder CT.sub.R, in accordance with one embodiment;

(10) FIG. 8a plots the transformation 1.sub.m.fwdarw.2 of the working fluid G.sub.R contained in the transfer cylinder CT.sub.R, in accordance with one embodiment;

(11) FIG. 8b plots the transformation c.sub.m.fwdarw.d of the working fluid G.sub.M contained in the transfer cylinder CT.sub.M, in accordance with one embodiment;

(12) FIG. 9a shows a driving machine, in accordance with one embodiment;

(13) FIG. 9b is a Mollier diagram for a UG variant, in accordance with one embodiment;

(14) FIG. 10a shows a receiving machine, in accordance with one embodiment;

(15) FIG. 10b is a Mollier diagram for a UG variant, in accordance with one embodiment;

(16) FIGS. 10c and 10d is a Mollier diagram for a ULG variant, in accordance with one embodiment;

(17) FIG. 11a is a plot of the cycles undergone in the driving machine and the receiving machine plotted diagrammatically in FIG. 8 showing pressure P as a function of the enthalpy h per unit mass for HFC R-134a, in accordance with one embodiment;

(18) FIG. 11b is a plot of the cycles undergone in the driving machine and the receiving machine plotted diagrammatically in FIG. 8 showing pressure P as a function of the enthalpy h per unit mass for HFC R-236fa, in accordance with one embodiment.

DETAILED DESCRIPTION

(19) FIG. 2a shows a transfer cylinder CT containing a transfer liquid LT and a working fluid G.sub.T that are not miscible, the liquid LT be more dense than the working fluid G.sub.T in the liquid state. The pipe 1 allows exit or entry of the transfer liquid, the pipes 2 and 3 allow entry and exit of the working fluid G.sub.T, and there is a thermally-insulative coating 4.

(20) FIG. 2b shows a transfer cylinder in which the transfer liquid LT and the condenser C.sub.T are separated by a flexible membrane 5 fastened to the upper part of the cylinder, for example by a clamp 6.

(21) FIG. 2c shows a transfer cylinder in which the liquid LT and the working fluid G.sub.T are separated by a float 7.

(22) The transfer liquid LT is chosen from liquids that have a low saturated vapor pressure at the operating temperature of the installation in order, in the absence of any separator membrane as described above, to avoid limitations caused by the diffusion of vapor from the working fluid G.sub.T through the vapor of the liquid LT in the condenser or the evaporator. Subject to compatibility with the working fluid G.sub.T as referred to above, and by way of non-exhaustive example, the liquid LT may be water or a mineral or synthetic oil, preferably having a low viscosity.

(23) The working fluid G.sub.T undergoes transformations in a thermodynamic range of temperature and pressure that is preferably compatible with liquid/vapor equilibrium, i.e. between the melting point and the critical temperature. However, during the modified Carnot cycle, some of these transformations may occur in whole or in part in the domain of the subcooled liquid or the superheated vapor or in the supercritical domain. A working fluid is preferably chosen from pure bodies and azeotropic mixtures in order to have a monovariant relation between temperature and pressure at liquid/vapor equilibrium. However, an installation of the invention may equally operate with a non-azeotropic solution as the working fluid.

(24) The working fluid G.sub.T may be water, CO.sub.2, or NH.sub.3, for example. The working fluid may further be chosen from alcohols having 1 to 6 carbon atoms, alkanes having 1 to 18 (more particularly 1 to 8) carbon atoms, chlorofluoroalkanes preferably having 1 to 15 (more particularly 1 to 10) carbon atoms, and partially or totally fluorinated, or chlorinated alkanes preferably having 1 to 15 (more particularly 1 to 10) carbon atoms. There may be mentioned in particular 1,1,1,2-tetrafluoroethane, propane, isobutane, n-butane, cyclobutane, and n-pentane. FIG. 3 plots the liquid/vapor equilibrium curves for a few of the above-mentioned working fluids G.sub.T. The saturated vapor pressure P (in bar) is plotted on a logarithmic scale up the ordinate axis as a function of the temperature T (in C.) plotted along the abscissa axis.

(25) The working fluids G.sub.R and G.sub.M and the transfer liquid LT are generally chosen first as a function of the temperatures of the available heat sources and heat sinks in the machine, together with the maximum and minimum saturated vapor pressures required, then as a function of other criteria such as in particular toxicity, impact on the environment, chemical stability, and cost.

(26) The working fluid G.sub.T in the transfer cylinder CT.sub.M or CT.sub.R may be in the two-phase liquid/vapor mixture state at the end of the adiabatic expansion step (modified dithermal Carnot driving cycle) or adiabatic compression step (modified dithermal Carnot receiving cycle). The liquid phase of the working fluid G.sub.T may then accumulate at the interface between the working fluid G.sub.T and the liquid LT. If the vapor content of the working fluid C.sub.T is high (typically in the range 0.95 to 1) in the transfer cylinder CT.sub.M or CT.sub.R before connecting said enclosure to the respective condenser C.sub.M or C.sub.R, total elimination of the liquid phase of the working fluid G.sub.T in these enclosures may be envisaged. Such elimination may be effected by maintaining the temperature of the working fluid G.sub.T in the transfer cylinder CT.sub.M or CT.sub.R at the ends of the steps of establishing communication between the transfer cylinder CT.sub.M or CT.sub.R and their respective condensers to a value above that of the working fluid G.sub.T in the liquid state in said condensers, so that there is no working fluid G.sub.T in the transfer cylinder CT.sub.M or CT.sub.R at this time.

(27) In one particular embodiment, the installation comprises means for exchange of heat between firstly the heat sources and the heat sinks that are at different temperatures and secondly the evaporators, the condensers, and where appropriate the working fluid G.sub.T in the transfer cylinders CT.sub.M and CT.sub.R, so as to eliminate all risk of condensation of the working fluid G.sub.M in the transfer cylinder CT.sub.M or the working fluid G.sub.R in the transfer cylinder CT.sub.R. FIG. 4 shows one embodiment of a transfer cylinder that allows exchange of heat. Said cylinder comprises a double envelope 8 in which a heat-exchange fluid may circulate, with an inlet 9 and an outlet 10 for said heat-exchange fluid.

(28) In the present text, a component comprising a transfer cylinder CT.sub.M and a transfer cylinder CT.sub.R is referred to as a CT.sub.M/CT.sub.R component.

(29) In a first embodiment corresponding to a basic configuration, an installation of the present invention comprises a single CT.sub.M/CT.sub.R component.

(30) In a second embodiment, an installation comprises two CT.sub.M/CT.sub.R components CT.sub.M/CT.sub.R and CT.sub.R/CT.sub.R.

(31) In a third embodiment, an installation comprises two components CT.sub.M/CT.sub.R and CT.sub.M/CT.sub.R, two separate pressurization devices BS.sub.M1 and BS.sub.M2 for the driving machine, and two separate pressurization devices BS.sub.R1 and BS.sub.R2 for the receiving machine.

(32) FIG. 5 shows an example of an installation conforming to the basic configuration of the first embodiment (designated U0), i.e. comprising a single CT.sub.M/CT.sub.R component. In this example: the driving machine comprises a hydraulic pump PH for circulating the fluid in the liquid state; an evaporator E.sub.M connected to a heat source at the temperature T.sub.hM; a transfer cylinder CT.sub.M containing in a lower portion a transfer liquid LT and in an upper portion the driving working fluid G.sub.M; a condenser C.sub.M; a separator bottle BS.sub.M that recovers the condensates; solenoid valves EV.sub.c and EV.sub.d on the pipes between the transfer cylinder CT.sub.M and the evaporator E.sub.M and the condenser C.sub.M, respectively; a solenoid valve EV.sub.a between the separator bottle BS.sub.M and the hydraulic pump PH; the receiving machine comprises: an evaporator E.sub.R; a transfer cylinder CT.sub.R containing in a lower portion the same transfer liquid LT and in an upper portion the receiving working fluid G.sub.R; a condenser C.sub.R; a separator bottle BS.sub.R that recovers the condensates and also has an evaporator function at the temperature T.sub.hR; a liquid pressure reducer D; solenoid valves EV.sub.1 and EV.sub.2 on the pipes between the transfer cylinder CT.sub.R and the evaporator E.sub.R and the condenser C.sub.R, respectively; and a solenoid valve EV.sub.3 between separator bottle BS.sub.R and the pressure reducer D; and the driving machine and the receiving machine are connected by a pipe connected to the lower portions of the transfer cylinders CT.sub.R and of CT.sub.M that may be blocked by the valve EV.sub.T.

(33) In the FIG. 5 embodiment that corresponds to the basic configuration U0, each of the transfer cylinders shown is thermally insulated from the external environment and corresponds to FIG. 2a. It could be replaced by a cylinder maintained at a temperature sufficient to prevent condensation of the working fluid G.sub.M (or G.sub.R) in the transfer cylinder CT.sub.M (or CT.sub.R) in the form shown in FIG. 4.

(34) The thermodynamic cycles undergone by the receiving working fluid G.sub.R and the driving working fluid G.sub.M in the variant U0 of the installation are shown in the Mollier diagram (FIGS. 6a and 6b, respectively), which plots the logarithm LnP of the pressure as a function of h (the enthalpy per unit mass of the fluid), and in the Clausius-Clapeyron diagram (FIGS. 5c and 6d), which plots LnP as a function of (1/T). The relative position of the equilibrium straight line segments for the working fluid G.sub.M in the Clausius-Clapeyron diagram differ according to whether the operating mode of the trithermal or quadrithermal installation is HT driving/LT receiving (FIG. 5c) or HT receiving/LT driving (FIG. 5d).

(35) An operating cycle of an installation as shown in FIG. 5 consists of four successive stages beginning at times t.sub., t.sub., t.sub., and t.sub. and that are described below in the context of the HT driving/LT receiving operating mode. A cycle is described for operation under steady conditions. Unless otherwise indicated, the solenoid valves are closed.

(36) Stage (Between Time t.sub. and t.sub.)

(37) At the moment immediately preceding time t.sub., the level of the transfer liquid LT is low (B) in the transfer cylinder CT.sub.R and high (H) in the transfer cylinder CT.sub.M and the saturated vapor pressure of the receiving and driving working fluids is low and equal to P.sub.b in both cylinders. The configuration of the installation shown diagrammatically in FIG. 5 corresponds to this moment of the cycle.

(38) At time t.sub., the valve EV.sub.2 is opened to establish communication between the cylinder CT.sub.R, the condenser C.sub.R, and the separator bottle BS.sub.R, in which the vapor pressure of the receiving working fluid G.sub.R is P.sub.h. The pressure in the transfer cylinder CT.sub.R is then imposed rapidly by the liquid-vapor equilibrium of the working fluid G.sub.R in the separator bottle BS.sub.R, which is then exercising the immersed evaporator function. The heat necessary to evaporate she working fluid G.sub.R in the separator bottle BS.sub.R is supplied at the temperature T.sub.hR. Between times t.sub. and t.sub., the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation 1.fwdarw.2 shown in FIGS. 6a and 6c.

(39) Stage (Between Times t.sub. and t.sub.)

(40) At time t.sub., i.e. when the pressure of the working fluid G.sub.R in the transfer cylinder CT.sub.R reaches the value P.sub.h , the valve EV.sub.2 is left open and at the same time the solenoid valves EV.sub.a, EV.sub.c, EV.sub.T are opened and the pump PH is started. The consequences of this are:

(41) In the driving circuit: The liquid working fluid G.sub.M is aspirated into the separator bottle BS.sub.M and propelled by the pump into the evaporator E.sub.M, where it evaporates, taking heat from the hot source at the temperature T.sub.hM. The flow rate at which the working fluid G.sub.M enters the evaporator is equal to the saturated vapor outlet flow rate, with the result that this evaporator remains filled at all times and retains a constant heat exchange efficiency. Since the saturated vapor of the working fluid G.sub.M occupies a greater volume than the working fluid G.sub.M in the liquid state, the transfer liquid in the transfer cylinder CT.sub.M is propelled downwards. During this stage , the working fluid G.sub.M undergoes the transformations a a.fwdarw.b.fwdarw.b.sub.l.fwdarw.c plotted in FIGS. 6b and 6c. The heat necessary to heat the subcooled liquid (transformation b.fwdarw.b.sub.l) and then to evaporate the working fluid G.sub.M (transformation b.sub.l.fwdarw.c) is supplied by a heat source at the high temperature T.sub.hM. A small quantity of work W.sup.ab is consumed by the pump for the transformation a.fwdarw.b while a greater quantity of work W.sub.h is transferred during the transformation b.sub.l.fwdarw.c to the receiving circuit via the transfer liquid LT exercising the liquid piston function.

(42) In the receiving circuit: The transfer liquid LT in the transfer cylinder CT.sub.R is discharged at the high level (H), the saturated vapor of the working fluid G.sub.R condenses in the condenser C.sub.R, and the condensates accumulate in the separator bottle BS.sub.R. During this stage the working fluid G.sub.R undergoes the transformation 2.fwdarw.2.sub.1.fwdarw.3 plotted in FIGS. 6a and 6c. The condensation heat of the working fluid G.sub.R is delivered at the temperature T.sub.hR. There may be very slight or even no subcooling of the working fluid G.sub.R. If there is no subcooling, the points 2.sub.1 and 3 in FIG. 6a coincide.
Stage (Between Times t.sub. and t.sub.)

(43) At time t.sub., the valves EV.sub.a, EV.sub.c, and EV.sub.T are closed and the valve EV.sub.d is opened. The vapor pressure of the driving working fluid G.sub.M falls rapidly from the value P.sub.h to the value P.sub.b imposed by the liquid-vapor equilibrium in the condenser C.sub.M. The condensation heat is evacuated at the temperature t.sub.bM and the condensates of the working fluid G.sub.M accumulate in the separator bottle BS.sub.M. Between times t.sub. and t.sub., the working fluid G.sub.M contained in the transfer cylinder CT.sub.M undergoes the transformation c.fwdarw.d shown in FIGS. 6b and 6c.

(44) Stage (Between Times t.sub. and t.sub.)

(45) At time t.sub., i.e. when the pressure of the working fluid G.sub.M in the transfer cylinder CT.sub.M reaches the value P.sub.b, the valve EV.sub.2 is closed, the valve EV.sub.d is left open, and at the same time the solenoid values EV.sub.1, EV.sub.3, and EV.sub.T are opened. The consequences of this are:

(46) In the receiving circuit: The liquid working fluid G.sub.R is aspirated into the separator bottle BS.sub.R, expanded isenthalpically via the pressure reducer D (consisting of a capillary or a needle valve) and introduced in two-phase form into the evaporator E.sub.R, where it finally evaporates. The saturated vapor of the working fluid G.sub.R produced propels downward (B) the transfer liquid in the cylinder CT.sub.R. During this stage the fluid G.sub.R undergoes the transformations 3.fwdarw.4.fwdarw.1 plotted in FIGS. 6a and 6c. The heat necessary to evaporate the working fluid G.sub.R is taken at the low temperature T.sub.bR. Work W.sub.b is transferred during the transformation 4.fwdarw.1 to the receiving circuit via the transfer liquid LT.

(47) In the driving circuit: The transfer liquid LT in the transfer cylinder CT.sub.M is propelled upward (H), the saturated vapor of the working fluid G.sub.M condenses in the condenser C.sub.M, and the condensates accumulate in the separator bottle BS.sub.M. During this stage the working fluid G.sub.M undergoes the transformation d.fwdarw.a plotted in FIGS. 6b and 6c. The condensation heat of the working fluid G.sub.M is delivered at the temperature T.sub.bM. At the end of this stage, the installation is again in the state of the cycle.

(48) The heart of the invention consists of the stages and in the device for transferring work between the driving cycle and the receiving cycle via the transfer liquid LT exercising the liquid piston function.

(49) The various thermodynamic transformations undergone by the working fluids G.sub.R and G.sub.M and the levels of the transfer liquid LT are summarized in Table 1. The states of the actuators (the solenoid valves and a clutch of the pump PH) are summarized in Table 2, in which an X signifies that the corresponding solenoid valve is open or that the clutch of the pump PH is engaged.

(50) TABLE-US-00001 TABLE 1 LT level Step Transformations Location CT.sub.R CT.sub.M 1 .fwdarw. 2 BS.sub.R + C.sub.R + CT.sub.R B H a .fwdarw. b .fwdarw. b.sub.l .fwdarw. c E.sub.M + CT.sub.M H.fwdarw.B 2 .fwdarw. 2.sub.l .fwdarw. 3 BS.sub.R + C.sub.R + CT.sub.R B.fwdarw.H c .fwdarw. d CT.sub.M H B 3 .fwdarw. 4.fwdarw. 1 E.sub.R + CT.sub.R H.fwdarw.B d .fwdarw. a CT.sub.M + C.sub.M B.fwdarw.H

(51) TABLE-US-00002 TABLE 2 Step EV.sub.1 EV.sub.2 EV.sub.3 EV.sub.a EV.sub.c EV.sub.d EV.sub.T PH x x x x x x x x x x x x

(52) In the basic configuration (U0) shown in FIG. 5, the production of cold at the temperature T.sub.bR occurs only during the stage while the consumption of heat at the temperature T.sub.hM occurs only during the stage . Similarly, condensation in the two condensers is intermittent. Compared to these principal stages, the intermediate stages and have a shorter duration. The intermittent nature of the connection of the evaporators and condensers to the remainder of the driving or receiving circuit is problematic in that it induces notable variations in temperature (and therefore in pressure) in these components when they are isolated from the mass point of view (zero flow rate of the working fluid G.sub.M or G.sub.R) whilst remaining connected with the heat-exchange fluids at the temperature T.sub.hM or T.sub.bR. Compared to the ideal case in which the temperature of all components of the driving and receiving circuits would be stable, these fluctuations induce irreversibilities and therefore reduce the overall coefficient of performance of the trithermal or quadrithermal installation. It is nevertheless possible to attenuate these temperature fluctuations by using a second implementation of the method of the invention in an installation that comprises two CT.sub.M/CT.sub.R components CT.sub.M/CT.sub.R and CT.sub.M/CT.sub.R with modified Carnot cycles in phase opposition. Generally speaking, this second implementation improves the coefficients COP and COA relative to the variant U0 of the basic configuration shown in FIG. 5.

(53) An installation that comprises two components CT.sub.M/CT.sub.R and CT.sub.M/CT.sub.R and that function in accordance with modified. Carnot cycles in phase opposition, subject to the addition of further components, further enables various types of energy recovery: in a variant UL, energy is recovered by a receiving machine from a driving machine via the transfer liquid LT; in a variant UG, energy is recovered by the driving machine or the receiving machine via the gas phase (respectively the working fluid G.sub.M or the working fluid G.sub.R); in a variant ULG, which constitutes a combination of the variants CL and UG, energy is recovered via the transfer liquid and via the gas phase.

(54) In these three variants, energy recovery increases the coefficients COP and COA of the trithermal or quadrithermal installation.

(55) FIG. 7 shows an installation using the second implementation, i.e. comprising two elements, each comprising a transfer cylinder CT.sub.M and a transfer cylinder CT.sub.R, which elements make it possible to use the basic variant U0-OP with cycles in phase opposition, or the variant UL. In an installation according to FIG. 7: the receiving circuit comprises: a hydraulic pump PH for circulating the fluid in the liquid state; an evaporator E.sub.M connected to a heat source at the temperature T.sub.hM (not shown); two transfer cylinders CT.sub.M and CT.sub.M each containing in a lower portion the transfer liquid LT and in an upper portion the driving working fluid G.sub.M; a condenser C.sub.M connected to a heat sink at the temperature T.sub.bM (not shown); a separator bottle BS.sub.M that recovers the condensates; solenoid valves EV.sub.c and EV.sub.c on the pipes between the evaporator E.sub.M and the transfer cylinders CT.sub.M and C.sub.M, respectively; solenoid valves EV.sub.d and EV.sub.d on the pipes between the condenser C.sub.M and the transfer cylinders CT.sub.M and CT.sub.M, respectively; solenoid valves EV.sub.c and EV.sub.c on the pipes between the evaporator E.sub.M and the transfer cylinders CT.sub.M and CT.sub.M, respectively; and a solenoid valve EV.sub.a between the separator bottle BS.sub.M and the evaporator E.sub.M; the receiving circuit comprises: an evaporator E.sub.R connected to a heat source at the temperature T.sub.bR (not shown) two transfer cylinders CT.sub.R and CT.sub.R each containing in a lower portion the transfer liquid LT and in an upper portion the driving working fluid G.sub.R; a condenser C.sub.R connected to a heat sink at the temperature T.sub.hR (not shown); a separator bottle BS.sub.R that recovers the condensates and also exercises the evaporator function at the temperature T.sub.hR; a liquid pressure reducer D; solenoid valves EV.sub.1 and EV.sub.1 on the pipes between the evaporator E.sub.R and the transfer cylinders CT.sub.R and CT.sub.R, respectively; solenoid valves EV.sub.2 and EV.sub.2 on the nines between the condenser C.sub.R and the transfer cylinders CT.sub.R and CT.sub.R, respectively; and a solenoid valve EV.sub.3 between the separator bottle BS.sub.R and the evaporator E.sub.R; and the receiving circuit and the driving circuit are connected by pipes connected to the lower portion of the transfer cylinders CT.sub.R, CT.sub.R, CT.sub.M, and CT.sub.M via the valves EV.sub.R, EV.sub.R, EV.sub.M, EV.sub.M, and EV.sub.L, respectively, for selectively establishing communication between any two transfer cylinders.

(56) In the FIG. 7 embodiment, each of the transfer cylinders shown is thermally insulated from the environment and corresponds to FIG. 2a. It could be replaced by a cylinder maintained at a sufficient temperature to prevent condensation of the working fluid G.sub.M (or G.sub.R) in the transfer cylinder CT.sub.M (or CT.sub.R), of the form shown in FIG. 4.

(57) The installation shown in FIG. 7 comprises a driving machine and a receiving machine operating in accordance with two cycles in phase opposition.

(58) The first cycle employs the transfer cylinders CT.sub.M and CT.sub.R and the associated solenoid valves. The cycle in phase opposition with the first cycle employs the transfer cylinders CT.sub.M and CT.sub.R and the associated solenoid valves. The other components (evaporators, condensers, separator bottles, hydraulic pump or pump and pressure reducer) are common to both cycles.

(59) The variant U0-OP may be implemented in an installation as shown in FIG. 7 in which the valve EV.sub.L is closed or in a similar installation including neither the valve EV.sub.L nor the corresponding pipe. Its operation is not described here.

(60) The variant UL, which necessarily operates with two cycles in phase opposition, further improves the coefficients COP and COA for a minimum increase in the complexity of the installation (merely adding the solenoid valve EV.sub.L) to enable the variant. U0-OP. The operating cycle of the variant CL of the installation according to FIG. 7 consists of six successive stages starting at times t.sub., t.sub., t.sub., t.sub., t.sub., and t.sub..

(61) The chronology of the steps is shown in Table 3. The transformations undergone by the working fluid G.sub.R or G.sub.M are simultaneous for each step and successive from one step to the next. At the end of the step , the state is the same as at the beginning of the step . The cycles 1-1.sub.m-2-2.sub.1-3-4-1 undergone by the working fluid G.sub.R and a-b-b.sub.l-c-c.sub.m-d-a undergone by the working fluid G.sub.M are plotted in the Mollier diagrams of FIGS. 8a and 8b, respectively. Most of the transformations undergone by the working fluids G.sub.R and G.sub.M remain identical to those of the basic installation shown in FIG. 5. The essential difference in this variant UL is that work is transferred during the steps of partial depressurization of the working fluid G.sub.M to bring about partial pressurization of the working fluid G.sub.R, i.e. during the steps and .

(62) Table 4 indicates for each step (with an X) if the valves are open and if the pump PH is operating.

(63) Step (Between Times t.sub. and t.sub.)

(64) At the moment immediately preceding t.sub., she level of the transfer liquid LT is low (B) in the transfer cylinder CT.sub.R, high (H) in the transfer cylinders CT.sub.R and CT.sub.M, and intermediate (I) in the transfer cylinder CT.sub.M. Furthermore, the saturated vapor pressure of the receiving and driving working fluids are respectively low (P.sub.b) and high (P.sub.h) in the two transfer cylinders CT.sub.R and CT.sub.M. The configuration of the installation shown diagrammatically in FIG. 7 corresponds to this moment of the cycle.

(65) At time t.sub., the valves EV.sub.R, EV.sub.M, and EV.sub.L are opened, which establishes communication between the transfer cylinder CT.sub.R and the transfer cylinder CT.sub.M via the transfer liquid. All the other solenoid valves being closed, the vapor pressure of the receiving working fluid G.sub.R is in equilibrium with that of the driving working fluid G.sub.M. The value of this intermediate pressure P.sub.m is calculated via an energy balance for the closed system consisting of the two transfer cylinders CT.sub.R and CT.sub.M allowing for the state equation of the working fluids G.sub.R and G.sub.M. During this step the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation 1.fwdarw.1.sub.m while the working fluid G.sub.M contained in the transfer cylinder CT.sub.M undergoes the transformation c.fwdarw.c.sub.m (FIG. 8). Work W.sub.L is transferred via the transfer liquid from the transfer cylinder CT.sub.M to the transfer cylinder CT.sub.R. The level of the transfer liquid LT in the transfer cylinder CT.sub.R increases to an intermediate level (between the levels B and H) and the level of the transfer liquid LT in the transfer cylinder CT.sub.M decreases to the threshold B.

(66) Step

(67) At time t.sub. the solenoid valves open in the preceding step are closed; the transfer cylinders CT.sub.R and CT.sub.M are then isolated from each other.

(68) At time t, the valve EV.sub.2 is opened, which establishes communication between the transfer cylinder CT.sub.R, the condenser C.sub.R, and the separator bottle BS.sub.R in which the vapor pressure of the receiving working fluid G.sub.R is equal to P.sub.h. The pressure in the transfer cylinder CT.sub.R is then rapidly imposed by the liquid-vapor equilibrium of the working fluid G.sub.R in the separator bottle BS.sub.R, which is then exercising the immersed evaporator function. The heat necessary to evaporate the working fluid G.sub.R in the separator bottle BS.sub.R is supplied at the temperature T.sub.hR. During this step, the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation 1.sub.m.fwdarw.2 plotted in FIG. 8a.

(69) At time t.sub., the valve EV.sub.d is also opened. The vapor pressure of the driving working fluid G.sub.M in the transfer cylinder CT.sub.M, which was equal to P.sub.m, falls rapidly to the value P.sub.b imposed by the liquid-vapor equilibrium in the condenser C.sub.M. The condensation heat is evacuated at the temperature T.sub.bM and the condensate of the working fluid G.sub.M accumulates in the separator bottle BS.sub.M. During this step, the working fluid G.sub.M contained in the transfer cylinder CT.sub.M undergoes the transformation c.sub.m.fwdarw.d plotted in FIG. 8b.

(70) Step

(71) At time t.sub., i.e. when the pressure of the working fluid G.sub.R in the transfer cylinder CT.sub.R reaches the value P.sub.h and the pressure of the working fluid G.sub.M in the transfer cylinder CT.sub.M reaches the value P.sub.b, the solenoid valves EV.sub.2 and EV.sub.d are left open, the solenoid valves EV.sub.R, EV.sub.M, EV.sub.R, EV.sub.M, EV.sub.a, EV.sub.c, EV.sub.3, and EV.sub.1 are opened, and the pump PH is started. The consequences of this are:

(72) In the driving machine; In the transfer cylinder pair CT.sub.M/CT.sub.R: the liquid working fluid G.sub.M is aspirated into the separator bottle BS.sub.M, and propelled via the pump PH into the evaporator E.sub.M, where it evaporates taking heat from the hot source at the temperature T.sub.hM. The flow rate at which the working fluid G.sub.M is introduced into the evaporator is equal to the saturated vapor outlet flow rate, with the result that this evaporator always remains filled and retains a constant efficiency for the thermal exchange. The saturated vapors of the working fluid G.sub.M occupying a greater volume than the liquid working fluid G.sub.M, the transfer liquid in the transfer cylinder CT.sub.M is propelled from the level H to the level I. During this stage the working fluid G.sub.M undergoes the transformations a.fwdarw.b.fwdarw.b.sub.l.fwdarw.c plotted in FIG. 8b. The heat necessary to heat the subocoled liquid (transformation b.fwdarw.b.sub.l) and then to evaporate the working fluid G.sub.M (transformation b.sub.l.fwdarw.c) is supplied by a hot source at the high temperature T.sub.hM. A small amount of work W.sub.ab is consumed by the pump for the transformation a.fwdarw.b while a greater quantity of work W.sub.h is transferred during the transformation b.sub.l.fwdarw.c to the receiving machine via the transfer liquid LT exercising the liquid piston function. In the transfer cylinder pair CT.sub.M/CT.sub.R: the transfer liquid entering the transfer cylinder CT.sub.M (from the transfer cylinder CT.sub.R) is raised from level T to level H. The vapor of the working fluid G.sub.M is propelled into the condenser C.sub.M, where it condenses, and the condensate accumulates in the separator bottle BS.sub.M. In the as space common to the combination (CT.sub.M+C.sub.M+BS.sub.M) the working fluid G.sub.M undergoes the transformation d.fwdarw.a plotted in FIG. 8b. The heat given off by the condensation of the working fluid G.sub.M is delivered to the cold sink at the temperature T.sub.bM. An amount of work W.sub.b less than the amount of work. W.sub.h is transferred during this transformation d.fwdarw.a from the receiving machine to the driving machine via the transfer liquid LT exercising the liquid piston function.

(73) In the receiving machine: In the transfer cylinder pair CT.sub.M/CT.sub.R: the transfer liquid LT in the transfer cylinder CT.sub.R is propelled from the level I to the level H, the saturated vapor of the working fluid G.sub.R condenses in the condenser C.sub.R, and the condensate accumulates in the separator bottle BS.sub.R. The working fluid G.sub.R undergoes the transformation d.fwdarw.a plotted in FIG. 8a. The heat given off by the condensation of the working fluid G.sub.R is delivered at the temperature T.sub.hR. There may be very little or even no subcooling of the working fluid G.sub.R. In which situation the points 2.sub.1 and 3 in FIG. 8a coincide. In the transfer cylinder pair CT.sub.M/CT.sub.R: the receiving working fluid G.sub.R in the subcooled (or saturated) liquid state flows from the separator bottle BS.sub.R to the evaporator E.sub.R via the pressure reducer D; it undergoes the transformation 3.fwdarw.4 plotted in FIG. 8a. In the evaporator E.sub.R, the working fluid G.sub.M evaporates (transformation 4.fwdarw.1, FIG. 8a) and the saturated vapor of the working fluid G.sub.R propels the transfer liquid LT in the transfer cylinder CT.sub.R from the level H to the level I to the cylinder CT.sub.M.

(74) At the end of this step , the trithermal or quadrithermal installation has completed a half-cycle. The second half-cycle is symmetrical to the first with both the transfer cylinders CT.sub.M and CT.sub.M interchanged and also the transfer cylinders CT.sub.R and CT.sub.R interchanged.

(75) Step

(76) This step is equivalent, to the stage described above (same transformations c.fwdarw.c.sub.m and 1.fwdarw.1.sub.m), but this time it is the transfer cylinders CT.sub.M and CT.sub.R that are connected (by opening the solenoid valves EV.sub.R and EV.sub.M instead of the valves EV.sub.R and EV.sub.M) and the transfer liquid LT level variations in these transfer cylinders are respectively I.fwdarw.B and B.fwdarw.I.

(77) Step

(78) This step is equivalent to the step described above (same transformations c.sub.m.fwdarw.d and 1.fwdarw.2), but the transfer cylinders concerned are CT.sub.R and CT.sub.M (which implies opening the solenoid valves EV.sub.2 and EV.sub.d instead of the valves EV.sub.2 and EV.sub.d).

(79) Step

(80) This step is equivalent to the step described above. The transformations of the working fluids G.sub.M and G.sub.R are the same, but interchanging both the transfer cylinders CT.sub.M and CT.sub.M, and also the transfer cylinders CT.sub.R and CT.sub.R. The variations in the level of transfer liquid LT in these transfer cylinders and which solenoid valves are open are indicated in Tables 3 and 4.

(81) TABLE-US-00003 TABLE 3 LT level variations Step Transformations Location CT.sub.R CT.sub.R CT.sub.M CT.sub.M c .fwdarw. c.sub.m CT.sub.M I .fwdarw. 1 .fwdarw. 1.sub.m CT.sub.R B.fwdarw. I c.sub.m .fwdarw. d CT.sub.M + C.sub.M + BS.sub.M 1.sub.m .fwdarw. 2 CT.sub.R + C.sub.R + BS.sub.R d .fwdarw. a CT.sub.M + C.sub.M B .fwdarw. a .fwdarw. b PH b .fwdarw. b.sub.l .fwdarw. c CT.sub.M + E.sub.M H .fwdarw. 2 .fwdarw. 2.sub.l .fwdarw. 3 CT.sub.R + C.sub.R + I .fwdarw. BS.sub.R 3 .fwdarw. 4 D 4 .fwdarw. 1 CT.sub.R + E.sub.R H .fwdarw. c .fwdarw. c.sub.m CT.sub.M I .fwdarw. 1 .fwdarw. 1.sub.m CT.sub.R B .fwdarw. c.sub.m .fwdarw. d CT.sub.M + C.sub.M + BS.sub.M 1.sub.m .fwdarw. 2 CT.sub.R + C.sub.R + BS.sub.R d .fwdarw. a CT.sub.M + C.sub.M B .fwdarw.H a .fwdarw. b PH b .fwdarw. b.sub.l .fwdarw. c CT.sub.M + E.sub.M H .fwdarw. 2 .fwdarw. 2.sub.l .fwdarw. 3 CT.sub.R + C.sub.R + I .fwdarw. BS.sub.R 3 .fwdarw. 4 D 4 .fwdarw. 1 CT.sub.R + E.sub.R H .fwdarw.

(82) TABLE-US-00004 TABLE 4 Solenoid valves open or pump PH running Step 1 1 2 2 3 a c c d d R R M M L PH X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

(83) In a third embodiment of the invention, the device comprises two CT.sub.M/CT.sub.R components and the separator bottles BS of the driving and receiving cycles are duplicated. This variant enables not only partial recovery of energy between the driving machine and the receiving machine during the depressurization/pressurization stage (said transfer being enabled by the presence of the two transfer cylinder CT.sub.M/transfer cylinder CT.sub.R components), but also additional limitation of some irreversibilities. This advantage is obtained by avoiding excessive subcooling of the liquid transfer fluid G.sub.M before its introduction into the evaporator E.sub.M at high temperature and by aiming for an expansion of the liquid transfer fluid G.sub.R closer to the isentropic transformation than the isenthalpic transformation. The variant UG enables internal energy recovery (U) within the driving or receiving circuits via the gas phase of the working fluid (respectively G.sub.M or G.sub.R). The variant. ULG combines the variants UL and UG.

(84) An installation corresponding to the third embodiment and enabling the variant UG or the variant. ULG comprises a driving machine as shown in FIG. 9a and a receiving machine as shown in FIG. 10a, the two machines being connected via the transfer liquid. LT.

(85) The cycles undergone by the working fluids G.sub.M and G.sub.R are plotted in the Mother diagrams of FIGS. 9b and 10b for the variant UG and FIGS. 10c and 10d for the variant ULG, respectively.

(86) A driving machine according to FIG. 9a comprises: a pump PH for circulating the fluid in the liquid state; an evaporator E.sub.M connected to a heat source T.sub.hM (not shown); two transfer cylinders CT.sub.M and CT.sub.M each containing in a lower portion the transfer liquid PT and in an upper portion the driving working fluid G.sub.M; a bifurcation Tee TB.sub.M; a condenser C.sub.M connected to a heat sink at the temperature T.sub.bM (not shown); a first separator bottle BS.sub.M1 at a temperature close to (below) that of the heat sink at the temperature T.sub.bM; a second separator bottle BS.sub.M2 thermally insulated from the environment; solenoid valves EV.sub.C and EV.sub.C on the pipes between the evaporator E.sub.M and the transfer cylinders CT.sub.M and CT.sub.M, respectively; solenoid valves EV.sub.d and EV.sub.d on the pipes connected to the common branch of the Tee TB.sub.M and the transfer cylinders CT.sub.M and CT.sub.M, respectively, the other two branches of said Tee being connected to the condenser C.sub.M and the second separator bottle BS.sub.M2; a solenoid valve EV.sub.f between one branch of the Tee TB.sub.M and the condenser C.sub.M; a solenoid valve EV.sub.e between the other branch of the Tee TB.sub.M and the separator bottle BS.sub.M2; a solenoid valve EV.sub.a between the separator bottles BS.sub.M1, and BS.sub.M2; and a solenoid valve EV.sub.b between the separator bottle BS.sub.M2 and the evaporator E.sub.M.

(87) A receiving machine according to FIG. 10a comprises: an evaporator E.sub.R connected to a heat source at the temperature T.sub.bR (not shown) a bifurcation Tee TB.sub.R; two transfer cylinders CT.sub.R and CT.sub.R each containing in a lower portion the transfer liquid LT and in an upper portion the receiving working fluid G.sub.R; a condenser C.sub.R connected to a heat sink at the temperature T.sub.hR (not shown); a first separator bottle BS.sub.R1 chat is at a temperature close to that of the condenser C.sub.R by virtue of heat exchange with the heat sink/source at the temperature T.sub.hR; a second separator bottle BS.sub.R2 thermally insulated from the environment; solenoid valves EV.sub.1 and EV.sub.1 on the pipes connected to the common branch of the Tee TB.sub.R and to the transfer cylinders CT.sub.R and CT.sub.R, respectively, the other two branches of said Tee being connected to the evaporator E.sub.R and to the second separator bottle BS.sub.R2; solenoid valves EV.sub.2 and EV.sub.2 on the pipes between the condenser C.sub.R and the transfer cylinders CT.sub.R and CT.sub.R, respectively; a solenoid valve EV.sub.3 between the separator bottles BS.sub.R1 and BS.sub.R2; a solenoid valve EV.sub.4 between the separator bottle BS.sub.R2 and the evaporator E.sub.R; a solenoid valve EV.sub.5 between a branch of the Tee TB.sub.R and the separator bottle BS.sub.R2; and a solenoid valve EV.sub.6 between the evaporator E.sub.R and a branch of the Tee TB.sub.R.

(88) The receiving circuit and the driving circuit are connected by pipes connected to the lower portions of the transfer cylinders CT.sub.R, CT.sub.R, CT.sub.M, and CT.sub.M by the valves EV.sub.R, EV.sub.R, EV.sub.M, and EV.sub.M, respectively. The solenoid valve EV.sub.L enables selective communication between one of the transfer cylinders CT.sub.M or CT.sub.M and one of the transfer cylinders CT.sub.R or CT.sub.R.

(89) To implement the variant UG, the solenoid valve EV.sub.L and the pipe on which it is installed are not necessary. If they exist in the installation, the solenoid valve EV.sub.L is closed.

(90) In the embodiment of FIGS. 9 and 10, each transfer cylinder shown is thermally insulated from the environment and corresponds to FIG. 2a. It could be replaced by a transfer cylinder maintained at a temperature sufficient to prevent condensation of the working fluid G.sub.M (or G.sub.R) in the transfer cylinder CT.sub.M (or CT.sub.R), in the form shown in FIG. 4.

(91) The operating cycle of an installation according to the variant UG shown in FIGS. 9a and 10a consists of six successive stages starting at times t.sub., t.sub., t.sub., t.sub., t.sub., and t.sub..

(92) The chronology of the steps is shown in Table 5. The transformations undergone by the working fluid G.sub.R or G.sub.M are simultaneous for each step and successive from one step to the next. At the end of the step , the state is the same as at the beginning of the step . The cycles 1-1.sub.1-2-3-3.sub.i-4-1 undergone by the working fluid G.sub.R and a-a.sub.j-b-b.sub.l-c-c.sub.j-d-a undergone by the working fluid G.sub.M are plotted in the Mollier diagrams of FIGS. 10b and 9b, respectively. Most of the transformations undergone by the working fluids G.sub.R and G.sub.M remain identical to those of the basic installation (variant U0, FIG. 5). The essential difference in this variant UG is that internal energy is recovered during the steps of partial pressure drop of the working fluids G.sub.M and G.sub.R in order to bring about partial pressurization of the working fluids G.sub.M and G.sub.M, respectively, during the steps and .

(93) Table 6 indicates for each step (with an X) if the valves are open and if the pump PH is operating.

(94) At the moment immediately preceding time t.sub., the level of the transfer liquid LT is low (B) in the transfer cylinders CT.sub.R and CT.sub.M and high (H) in the transfer cylinders CT.sub.R and CT.sub.M. Moreover, the saturated vapor pressure of the receiving working fluid G.sub.R and the driving working fluid G.sub.M is low (P.sub.b) in the transfer cylinders CT.sub.R and CT.sub.M and high (P.sub.h) in the transfer cylinders CT.sub.R and CT.sub.M. The separator bottles BS.sub.R2 and BS.sub.M2 respectively contain the working fluids G.sub.R and G.sub.M in the saturated liquid state and at the same high pressure P.sub.h. The configuration of the installation shown diagrammatically in FIGS. 9a and 10a corresponds to this moment of the cycle.

(95) TABLE-US-00005 TABLE 5 LT level variations Step Transformations Location CT.sub.R CT.sub.R CT.sub.M CT.sub.M a .fwdarw. a.sub.j BS.sub.M2 c .fwdarw. c.sub.j CT.sub.M 1 .fwdarw. 1.sub.i CT.sub.R 3 .fwdarw. 3.sub.i BS.sub.R2 a.sub.j .fwdarw. b.fwdarw.b.sub.l PH + E.sub.M c.sub.j .fwdarw. d CT.sub.M + C.sub.M + BS 1.sub.i .fwdarw. 2 CT.sub.R + C.sub.R + BS.sub.R 3.sub.i .fwdarw. 4 EV.sub.4 (b.fwdarw.) b.sub.l .fwdarw. c E.sub.M + CT.sub.M H d .fwdarw. a CT.sub.M + C.sub.M+ B 2 .fwdarw. 3 CT.sub.R + C.sub.R + BS.sub.R B .fwdarw. 4 .fwdarw. 1 E.sub.R + CT.sub.R H a .fwdarw. a.sub.j BS.sub.M2 c .fwdarw. c.sub.j CT.sub.M 1 .fwdarw. 1.sub.i CT.sub.R 3 .fwdarw.3.sub.i BS.sub.R2 a.sub.j .fwdarw. b.fwdarw. b.sub.l PH + E.sub.M c.sub.j .fwdarw. d CT.sub.M + C.sub.M + BS.sub.M 1.sub.i .fwdarw. 2 CT.sub.R + C.sub.R + BS 3.sub.i .fwdarw. 4 EV.sub.4 (b.fwdarw.) b.sub.l .fwdarw. c E.sub.M + CT.sub.M H d .fwdarw.a CT.sub.M + C.sub.M+ B .fwdarw. 2 .fwdarw. 3 CT.sub.R + C.sub.R + BS B .fwdarw. 4 .fwdarw. 1 E.sub.R + CT.sub.R H .fwdarw.

(96) TABLE-US-00006 TABLE 6 Ste 1 1 2 2 3 4 5 6 a b c c d d e f R M P X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
Step (Between Times t and t)

(97) In the driving circuit: At time t.sub., the solenoid valves EV.sub.d and EV.sub.e are opened to establish communication between the transfer cylinder CT.sub.M and the separator bottle BS.sub.M2. The working fluid G.sub.M undergoes the transformation a.fwdarw.a.sub.j in the separator bottle BS.sub.M2 and the transformation c.fwdarw.c.sub.j in the transfer cylinder CT.sub.M. The high-pressure saturated vapor from the transfer cylinder CT.sub.M is partly condensed in the separator bottle BS.sub.M2, increasing the pressure therein and the temperature of the working fluid G.sub.M. The final pressure P.sub.j is calculated from an internal energy conservation balance for the closed adiabatic system consisting of these two components (BS.sub.M2 and CT.sub.M), taking into account the state equation (P versus V, T) and the liquid-vapor equilibrium of the working fluid G.sub.M. The reduction in internal energy (U.sub.cU.sub.cj) is compensated by the increase (U.sub.ajU.sub.a). These two internal variations are denoted W.sub.GM (=U.sub.cU.sub.cj=U.sub.ajU.sub.a) in FIG. 9b although this is not an exchange of work between the transfer cylinder CT.sub.M and the separator bottle BS.sub.M2.

(98) In the receiving circuit: Simultaneously (at time t.sub.), the solenoid valves EV.sub.1 and EV.sub.5 are opened, which establishes communication between the transfer cylinder CT.sub.R and the separator bottle BS.sub.R2. The working fluid G.sub.R undergoes the transformation 3.fwdarw.3.sub.i in the separator bottle BS.sub.R2 and the transformation 1.fwdarw.1.sub.i in the transfer cylinder CT.sub.R. A portion of the liquid evaporates in the separator bottle BS.sub.R2, which has the two-fold consequence of reducing its temperature and increasing the pressure in the transfer cylinder CT.sub.R. The final pressure P.sub.i is calculated in the same way as the pressure P.sub.j, but with liquid-vapor equilibrium of the working fluid G.sub.R. In the same way, the two internal energy variations (U.sub.3U.sub.3i) and (U.sub.1iU.sub.1) are denoted W.sub.GR for convenience in FIG. 10b, although this is not an exchange of work between the separator bottle BS.sub.R2 and the transfer cylinder CT.sub.R.
Step

(99) In the driving circuit: At time t.sub., the above solenoid valves are closed, except for the solenoid valve EV.sub.d. The solenoid valve EV.sub.b is opened and the pump PH is actuated to establish communication between the separator bottle BS.sub.M2 and the evaporator E.sub.M. The working fluid G.sub.M in the saturated liquid state is introduced into the evaporator and undergoes the transformation a.sub.j.fwdarw.b in the pump PH and then the transformation b.fwdarw.b.sub.l in the evaporator E.sub.M.

(100) Simultaneously (at time t.sub.), the solenoid valve EV.sub.f is opened, which establishes communication between the transfer cylinder CT.sub.M and the condenser C.sub.M. The vapor pressure of the driving working fluid G.sub.M, which was equal to P.sub.j, falls rapidly to the value P.sub.b imposed by the liquid-vapor equilibrium in the condenser C.sub.M. The condensation heat is evacuated at the temperature T.sub.bM and the condensates of the working fluid G.sub.M accumulate in the separator bottle BS.sub.M1. Between times t.sub. and t.sub., the working fluid GM contained in the transfer cylinder CT.sub.M undergoes the transformation c.sub.j.fwdarw.d.

(101) In the receiving circuit: At the same time t.sub. the solenoid valve EV.sub.4 is opened, which establishes communication between the separator bottle BS.sub.R2 and the evaporator E.sub.R. The working fluid G.sub.R in the saturated liquid state undergoes the isenthalpic transformation 3.sub.i.fwdarw.4 before being introduced into the evaporator E.sub.R. Simultaneously (at time t.sub.), the solenoid valve EV.sub.2 is opened, which establishes communication between the transfer cylinder CT.sub.R, the condenser C.sub.R, and the separator bottle BS.sub.R1. The vapor pressure of the receiving working fluid G.sub.R, which was equal to P.sub.i in the transfer cylinder CT.sub.R, increases rapidly to the value P.sub.h imposed by the liquid/vapor equilibrium in the separator bottle BS.sub.R1 exercising the evaporator function. The evaporation heat is at the temperature T.sub.hR and the level of the liquid working fluid G.sub.R contained in the separator bottle BS.sub.R1 decreases during this step. Between times t.sub. and t.sub., the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation 1.sub.i.fwdarw.2.
Step

(102) The solenoid valves previously open are kept open, except for the valves EV.sub.4 and EV.sub.b, and the pump PH is stopped.

(103) At time t.sub., the solenoid valves EV.sub.1, EV.sub.3, EV.sub.6, EV.sub.a, EV.sub.c, EV.sub.R, EV.sub.R, EV.sub.M, and EV.sub.M are also opened. This step constitutes the main step of this half-cycle, because it is that during which useful exchanges of heat occur between the trithermal or quadrithermal installation and the exterior environment.

(104) Opening both the solenoid valves EV.sub.c, EV.sub.M, and EV.sub.R (with the valve EV.sub.2 already open) and also EV.sub.1, EV.sub.6, EV.sub.R, and EV.sub.M (with the valves EV.sub.d and EV.sub.f already open) has the following consequences:

(105) In the driving circuit M:

(106) Because of the opening of the solenoid valve EV.sub.a, the working fluid G.sub.M in the saturated liquid state that has accumulated in the first separator bottle BS.sub.M1 flows under gravity into the second separator bottle BS.sub.M2. The consequences of this are as follows: In the pair CT.sub.M/CT.sub.R: the liquid working fluid G.sub.M coming from the separator bottle BS.sub.M2 is heated if the transformation b.fwdarw.b.sub.l has not completely finished at the end of the previous step) and is evaporated in the evaporator E.sub.M (transformation b.sub.l.fwdarw.c). The saturated vapor of the working fluid G.sub.M produced propels the transfer liquid in the transfer cylinder CT.sub.M from the high level to the low level. The heat necessary for de-subcooling (transformation b.fwdarw.b.sub.l) and then evaporating (transformation b.sub.l.fwdarw.c) the working fluid G.sub.M is supplied by the heat source at the high temperature T.sub.hM. Work W.sub.h is transferred during the transformation b.sub.l.fwdarw.c to the receiving circuit. In the pair CT.sub.M/CT.sub.R: the transfer liquid coming from the transfer cylinder CT.sub.R is propelled in the low-level transfer cylinder CT.sub.M from the low level to the high level; this corresponds to a transfer of work W.sub.b (less than the work W.sub.h in absolute value) from the receiving circuit to the driving circuit.

(107) The saturated vapor of the working fluid G.sub.M is condensed (transformation d.fwdarw.a) in the condenser C.sub.M and the condensate passes through the separator bottle BS.sub.M1, after which it accumulates in the separator bottle BS.sub.M2 the valve EV.sub.a being open). The condensation heat of the working fluid G.sub.M is delivered at the temperature T.sub.bM.

(108) In the receiving circuit R:

(109) Because of the opening of the solenoid valve EV.sub.3, the working fluid G.sub.R in the saturated liquid state that has accumulated in the first separator bottle BS.sub.R1 flows under gravity into the second separator bottle BS.sub.R2. The consequences of this are as follows: In the pair CT.sub.M/CT.sub.R: the transfer liquid coming from the transfer cylinder CT.sub.M is propelled in the transfer cylinder CT.sub.R from the low level to the high level. The saturated vapor of the working fluid G.sub.R is condensed in the condenser C.sub.R, and the condensate accumulates in the separator bottle BS.sub.R1 (transformation 2.fwdarw.3). The condensation heat of the working fluid G.sub.R is delivered at the temperature T.sub.hR. In the pair CT.sub.M/CT.sub.R: the working fluid G.sub.R evaporates in the evaporator E.sub.R (transformation 4.fwdarw.1). The saturated vapor of the working fluid G.sub.R produced propels the transfer liquid in the transfer cylinder CT.sub.R from the high level to the low level. The heat necessary to evaporate the working fluid G.sub.R is taken at the low temperature T.sub.bR.

(110) The steps of the second half-cycle are symmetrical to those of the first half-cycle with the only modification being simply to interchange both the transfer cylinders CT.sub.M and CT.sub.M and also the transfer cylinders CT.sub.R and CT.sub.R (see Tables 5 and 6).

(111) The operating cycle of an installation according to FIGS. 9a and 10a in the variant ULG consists of eight successive stages starting at times t.sub., t.sub., t.sub., t.sub., t.sub., t.sub., t.sub., and t.sub..

(112) The chronology of the steps with the transformations under one by the working fluids G.sub.M or G.sub.M is set out in Table 7. At the end of the step the state is the same as at the start of the step . The cycles 1-1.sub.l-1.sub.m-2-3-3.sub.i-4-1 undergone by the working fluid G.sub.R and a-a.sub.j-b-b.sub.l-c-c.sub.j-c.sub.m-d-a undergone by the working fluid G.sub.M are plotted in the Mollier diagrams of FIGS. 10c and 10d, respectively. The transformations undergone by the working fluids G.sub.R and G.sub.M are a combination of those undergone in the variants UL and UG of the installation diagrammatically shown in FIGS. 9a and 10a.

(113) Table 8 indicates for each step (with an X) if the valves are open and if the pump PH is operating.

(114) At the moment immediately preceding time t.sub., the level of the transfer liquid LT is low (B) in the transfer cylinder CT.sub.R, intermediate (I) in the transfer cylinder CT.sub.M, and high (H) in the transfer cylinders CT.sub.R and CT.sub.M. What is more, the saturated vapor pressure of the receiving working fluid G.sub.R and the driving working fluid G.sub.M is low (P.sub.b) in the cylinders CT.sub.R and CT.sub.M and high (P.sub.h) in the transfer cylinders CT.sub.R and CT.sub.M. Finally, the separator bottles BS.sub.R2 and BS.sub.M2 contain the working fluids G.sub.R and G.sub.M, respectively, in the saturated liquid state and at the same high pressure P.sub.h.

(115) TABLE-US-00007 TABLE 7 LT level variations Steps Transformations Location CT.sub.R CT.sub.R CT.sub.M CT.sub.M a .fwdarw. a.sub.j BS.sub.M2 c .fwdarw. c.sub.j CT.sub.M 1 .fwdarw. 1.sub.i CT.sub.R 3 .fwdarw. 3.sub.i BS.sub.R2 c.sub.j .fwdarw. c.sub.m CT.sub.M I .fwdarw. 1.sub.i .fwdarw. 1.sub.m CT.sub.R B .fwdarw. a.sub.j .fwdarw. b.fwdarw. b.sub.l PH + E.sub.M c.sub.m .fwdarw. d CT.sub.M + C.sub.M + BS.sub.M1 1.sub.m .fwdarw. 2 CT.sub.R + C.sub.R + BS.sub.R1 3.sub.i .fwdarw. 4 EV.sub.4 (b.fwdarw.) b.sub.l .fwdarw. c E.sub.M + CT.sub.M H .fwdarw. d .fwdarw. a CT.sub.M + C.sub.M + B .fwdarw. BS.sub.M1 2 .fwdarw. 3 CT.sub.R + C.sub.R + BS.sub.R1 I .fwdarw. 4 .fwdarw. 1 E.sub.R + CT.sub.R H .fwdarw. a .fwdarw. a.sub.j BS.sub.M2 c .fwdarw. c.sub.j CT.sub.M 1 .fwdarw. 1.sub.i CT.sub.R 3 .fwdarw. 3.sub.i BS.sub.R2 c.sub.j .fwdarw. c.sub.m CT.sub.M I .fwdarw. 1.sub.i .fwdarw. 1.sub.m CT.sub.R B .fwdarw. a.sub.j .fwdarw. b.fwdarw. b.sub.l PH + E.sub.M c.sub.j .fwdarw. d CT.sub.M + C.sub.M + BS.sub.M1 1.sub.i .fwdarw. 2 CT.sub.R + C.sub.R + BS.sub.R1 3.sub.i .fwdarw. 4 EV.sub.4 (b.fwdarw.) b.sub.l .fwdarw.c E.sub.M + CT.sub.M H .fwdarw. d .fwdarw.a CT.sub.M + C.sub.M + B .fwdarw. BS.sub.M1 2 .fwdarw. 3 CT.sub.R + C.sub.R + I .fwdarw. BS.sub.R1 4 .fwdarw. 1 E.sub.R + CT.sub.R H .fwdarw.

(116) TABLE-US-00008 TABLE 8 St 1 1 2 2 3 4 5 6 a b c c d d e f R M L PH X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
Step (Between Times t and t)

(117) In the driving circuit: At time t.sub., the solenoid valves EV.sub.d and EV.sub.e are opened, which establishes communication between the transfer cylinder CT.sub.M and the separator bottle BS.sub.M2. The working fluid G.sub.M undergoes the transformation a.fwdarw.a.sub.j in the separator bottle BS.sub.M2 and the transformation c.fwdarw.c.sub.j in the transfer cylinder CT.sub.M. The high-pressure saturated vapor coming from the transfer cylinder CT.sub.M is partly condensed in the separator bottle BS.sub.M2, increasing the pressure therein and the temperature of the working fluid G.sub.M. The final pressure P.sub.j is calculated from an internal energy conservation balance for the closed adiabatic system consisting of these two components (BS.sub.M2 and CT.sub.M) and taking into account the state equation (P versus V, T) and the liquid-vapor equilibrium of the working fluid G.sub.M. The reduction of internal energy (U.sub.cU.sub.cj) is compensated by the increase (U.sub.ajU.sub.a). These two internal variations are denoted W.sub.GM (=U.sub.cU.sub.cj=U.sub.ajU.sub.a) in FIG. 10d, although this is not an exchange of work between the transfer cylinder CT.sub.M and the separator bottle BS.sub.M2.

(118) In the receiving circuit: Simultaneously (at time t.sub.), the solenoid valves EV.sub.1 and EV.sub.5 are opened, which establishes communication between the transfer cylinder CT.sub.R and the separator bottle BS.sub.R2. The working fluid G.sub.R undergoes the transformation 3.fwdarw.3.sub.i in the separator bottle BS.sub.R2 and the transformation 1.fwdarw.1.sub.i in the transfer cylinder CT.sub.R. A portion of the liquid evaporates in the separator bottle BS.sub.R2, which has the two-fold consequence of reducing its temperature and increasing the pressure in the transfer cylinder CT.sub.R. The final pressure P.sub.i is calculated in the same way as the pressure P.sub.j, but with liquid-vapor equilibrium of the working fluid G.sub.R. In the same way, the two variations in internal energy (U.sub.3U.sub.3i) and (U.sub.1iU.sub.1) are denoted W.sub.GR in FIG. 10c although this is not an exchange of work between the separator bottle BS.sub.R2 and the transfer cylinder CT.sub.R.
Step

(119) At time t.sub., the valves EV.sub.R, EV.sub.M, and EV.sub.L are opened, which establishes communication via the transfer liquid between the transfer cylinder CT.sub.R and the transfer cylinder CT.sub.M. All the other solenoid valves being closed, the vapor pressure of the receiving working fluid G.sub.R is in equilibrium with that of the driving working fluid G.sub.M. The value of this intermediate pressure P.sub.m is calculated by an energy balance or the closed system consisting of the two transfer cylinders CT.sub.R and CT.sub.M, taking into account the state equation of the working fluids G.sub.R and G.sub.M. During this step, the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation li.fwdarw.lm and the working fluid G.sub.M contained in the cylinder CT.sub.M undergoes the transformation cj.fwdarw.cm (FIG. 10c-10d). Work W.sub.L is transferred via the transfer liquid from the transfer cylinder CT.sub.M to the transfer cylinder CT.sub.R. The level of the transfer liquid LT in the transfer cylinder CT.sub.R increases to an intermediate level I and the level of the transfer liquid LT in the transfer cylinder CT.sub.M decreases to the threshold B.

(120) Step

(121) In the driving circuit: At time t.sub. the above solenoid valves are closed, the solenoid valve EV.sub.b is opened, and the pump PH is actuated, which establishes communication between the separator bottle BS.sub.m2 and the evaporator E.sub.M. The working fluid G.sub.M in the saturated liquid state is introduced into the evaporator and undergoes the transformation a.sub.j.fwdarw.b in the pump PH and then the transformation b.fwdarw.b.sub.l in the evaporator E.sub.M.

(122) Simultaneously (at time t.sub.) the solenoid valves EV.sub.d and EV.sub.f are opened, which establishes communication between the transfer cylinder CT.sub.M and the condenser C.sub.M. The vapor pressure of the driving working fluid G.sub.M, which was equal to P.sub.m, falls rapidly to the value P.sub.b imposed by the liquid-vapor equilibrium in the condenser C.sub.M. The condensation heat is evacuated at the temperature T.sub.bM and the condensate of the working fluid G.sub.M accumulates in the separator bottle BS.sub.M1. Between times t.sub. and t.sub., the working fluid G.sub.M contained in the transfer cylinder CT.sub.M undergoes the transformation c.sub.m.fwdarw.d.

(123) In the receiving circuit: At the same time t.sub. the solenoid valve EV.sub.4 is opened, which establishes communication between the separator bottle BS.sub.R2 and the evaporator E.sub.R. The working fluid G.sub.R in the saturated liquid state undergoes the isenthalpic transformation 3.sub.i.fwdarw.4 before being introduced into the evaporator E.sub.R.

(124) Simultaneously (at time t.sub.), the solenoid valve EV.sub.2 is opened, which establishes communication between the transfer cylinder CT.sub.R, the condenser C.sub.R, and the separator bottle BS.sub.R1. The vapor pressure of the receiving working fluid G.sub.R, which was equal to P.sub.m in the transfer cylinder CT.sub.R, increases rapidly to the value P.sub.h imposed by the liquid-vapor equilibrium in the separator bottle BS.sub.R1 exercising the evaporator function. The evaporation heat is at temperature T.sub.hR and the level of liquid working fluid G.sub.R contained in the separator bottle BS.sub.R1 decreases during this step. Between times t.sub. and t.sub., the working fluid G.sub.R contained in the transfer cylinder CT.sub.R undergoes the transformation 1.sub.m.fwdarw.2.

(125) Step

(126) The solenoid valves previously open, except for the valves EV.sub.4 and EV.sub.b, are kept open and the pump PH is stopped.

(127) At time t.sub., the solenoid valves EV.sub.1, EV.sub.3, EV.sub.6, EV.sub.a, EV.sub.c, EV.sub.R, EV.sub.R, EV.sub.M, and EV.sub.M are also opened. This step constitutes the main step of this half-cycle, because it is during this step that useful exchanges of heat occur between the modified trithermal or quadrithermal Carnot machine and the exterior environment.

(128) Opening both the solenoid valves EV.sub.c, EV.sub.M, and EV.sub.R, (with the valve EV.sub.2 already open) and also EV.sub.1, EV.sub.R, and EV.sub.M (with the valves EV.sub.d and EV.sub.f already open) has the following consequences:

(129) In the driving circuit:

(130) Because of the opening of the solenoid valve EV.sub.a, the working fluid G.sub.M in the saturated liquid state that has accumulated in the first separator bottle BS.sub.M1 flows under gravity into the second separator bottle BS.sub.M2. The consequences of this are as follows: In the pair CT.sub.M/CT.sub.R: the liquid working fluid G.sub.M coming from the separator bottle BS.sub.M2 is heated if the transformation (b.fwdarw.b.sub.l) has not completely finished at the end of the previous step and is evaporated in the evaporator E.sub.M (transformation (b.sub.l.fwdarw.c). The saturated vapor of the working fluid G.sub.M produced propels the transfer liquid in the transfer cylinder CT.sub.M from the high level H to the intermediate level I. The heat necessary to de-subcool (transformation b.fwdarw.b.sub.l) and then to evaporate (transformation b.sub.l.fwdarw.c) the working fluid G.sub.M is supplied by the heat source at the high temperature T.sub.hM. Work W.sub.h is transferred during the transformation b.sub.l.fwdarw.c to the receiving circuit. In the pair CT.sub.M/CT.sub.R: the transfer liquid coming from the transfer cylinder CT.sub.R is propelled in the transfer cylinder CT.sub.M from the low level to the high level; this corresponds to a transfer of work W.sub.b (less than the work W.sub.h in absolute value) from the receiving circuit to the driving circuit.

(131) The saturated vapor of the working fluid G.sub.M is condensed (transformation d.fwdarw.a) in the condenser C.sub.M and the condensate passes through the separator bottle BS.sub.M1, after which it accumulates in the separator bottle BS.sub.M2 (the valve EV.sub.a being open). The condensation heat of the working fluid G.sub.M is delivered at the temperature T.sub.bM.

(132) In the receiving circuit R:

(133) Because of the opening of the solenoid valve EV.sub.3, the working fluid G.sub.R in the saturated liquid state that has accumulated in the first separator bottle BS.sub.R1 flows under gravity into the second separator bottle BS.sub.R2. The consequences of this are as follows: In the pair CT.sub.M/CT.sub.R: the transfer liquid coming from the transfer cylinder CT.sub.M is propelled in the transfer cylinder CT.sub.R from the intermediate level I to the high level H. The saturated vapors of the working fluid G.sub.R are condensed in the condenser C.sub.R (transformation 2.fwdarw.3) and the condensate passes through the separator bottle BS.sub.R1 and then accumulates in the separator bottle BS.sub.R2 (the valve EV.sub.3 being open). The condensation heat of the working fluid G.sub.R is delivered at the temperature T.sub.hR. In the pair CT.sub.M/CT.sub.R: the working fluid G.sub.R evaporates in the evaporator E.sub.R (transformation 4.fwdarw.1). The saturated vapor of the working fluid G.sub.R produced propels the transfer liquid in the transfer cylinder CT.sub.R from the high level to the low level. The heat necessary to evaporate the working fluid G.sub.R is taken at the low temperature T.sub.bR.

(134) The steps of the second half-cycle are symmetrical to those of the first half-cycle with the only modification being simply to interchange both the transfer cylinders CT.sub.M and CT.sub.M and also the transfer cylinders CT.sub.R and CT.sub.R (see Tables 7 and 8).

(135) The uses of an installation of the present invention depend in particular on the temperature of the heat sources and the heat sinks available and whether the operating mode adopted is HT driving/LT receiving or LT driving/HT receiving.

(136) In the HT driving/LT receiving operating mode represented diagrammatically in FIG. 1a, the temperature T.sub.hM of the hot source of the driving machine is above the temperature T.sub.hR of the heat sink of the receiving machine. In this first situation, the target applications are the production of cold at the temperature T.sub.bR lower than ambient temperature and/or the production of heat (with a coefficient of amplification COA.sub.3, the ratio of the heat delivered, at the temperatures T.sub.hR and T.sub.bM to the heat consumed at the temperature T.sub.hM, greater than 1) at the temperatures T.sub.hR and T.sub.bM above ambient temperature, which temperatures T.sub.hR and T.sub.bM may be the same. By way of illustration, subject to consumption of heat at the temperature T.sub.hM, this first operating mode enables freezing, refrigeration, habitation air-conditioning and/or heating functions.

(137) In the LT driving/HT receiving operating mode represented diagrammatically in FIG. 1b, the temperature T.sub.hM is below the temperature T.sub.hR. In this second situation, the target application is the production of heat at the temperature T.sub.hR above those of the two heat sources at the temperatures T.sub.bR and T.sub.hM (which may be the same, as represented in FIG. 1b), but this time with a coefficient of amplification (the ratio of the heat delivered at the temperature T.sub.hR to the heat consumed at the temperatures T.sub.bR and T.sub.hM) less than unity. This second operating mode thus exploits waste heat at medium temperatures.

(138) For each of these two operating modes, the installation may operate in accordance with the variants U0, U0-OP, UL, UG, and ULG described above.

(139) Examples of possible uses of installations of the present invention are described in more detail below by way of illustration only. The invention is not limited to these examples, however.

Example 1

Use of the Invention to Cool a Habitat Using Heat Supplied by Flat Solar Panels

(140) In this application, the method operates in the HT driving/LT receiving mode. By way of working fluids, 1,1,1,3,3,3-hexafluoropropane (HFC R236fa) may be used for the driving working fluid and tetrafluoroethane (HFC R-134a) for the receiving working fluid. These two working fluids are not harmful to the ozone layer, non-inflammable, non-toxic, and produced on an industrial scale.

(141) The temperature T.sub.hM (produced by the plane solar panels) is equal to 65 C.

(142) The temperature T.sub.bR required for the production of cold in the evaporator E.sub.R is set at 12 C. This temperature is compatible with the use of a cooling floor in the habitat with recommended entry of the heatexchange fluid at a temperature of approximately 18 C.

(143) With these constraints and given the liquid/vapor equilibrium of these working fluids (see FIG. 3), the high pressure P.sub.h and the low pressure P.sub.b (see FIGS. 6abc, 8ab, 10bcd) and the temperatures T.sub.bM and T.sub.hR may be deduced: Pressures P.sub.h=3.69 bar, P.sub.b=4.43 bar, i.e. pressures that are neither too low, which would penalize the transfer of vapor of the working fluid G.sub.R or G.sub.M, nor too high, which would compromise the safety of the installation; Temperatures T.sub.bM=40.3 C., T.sub.hR=34.3 C., i.e. temperatures above an average summer ambient temperature enabling evacuation to the exterior environment of the heat given off by the condensers C.sub.R and C.sub.M.

(144) A quadrithermal Carnot machine operating between these temperatures T.sub.hM, T.sub.bM, T.sub.bR, T.sub.hR would have an ideal coefficient of performance (COP.sub.c4) equal to 0.93.

(145) The performance of the machine has been compared to that of the variants UO, UL, and ULG of the quadrithermal installation of the invention operating under the conditions defined above. The coefficients of performance of the installation operating under steady conditions, determined for the three variants by means of an energy balance, are as follows: COP.sub.4(U0)=0.025; COP.sub.4(UL)=0.56; COP.sub.4(ULG)=0.34.

(146) The coefficient of performance of the variant U0 is clearly inadequate and the variant U0-OP gives only a slight improvement.

(147) The coefficient of performance of the variant UL is highly satisfactory. Relative to the Carnot maximum COP, an exceptional efficiency (COP.sub.4(UL)/COP.sub.C460%) is obtained compared to the current state of the art, where as a general rule this ratio33%. The description of the cycles undergone in the driving machine and the receiving machine plotted diagrammatically in FIG. 8 is plotted accurately for this application in FIGS. 11a and 11b, which show the pressure P (in megapascals (MPa)) as a function of the enthalpy h per unit mass (in kilojoules per kilogram (kJ/kg)) for HFC R-134a (FIG. 11a) and for HFC R-236fa (FIG. 11b).

(148) Note that the isentropic expansion c.fwdarw.c.sub.m ends with the fluid R236fa in the superheated vapor domain, which is favorable, in contrast to the situation plotted in FIG. 8b.

Example 2

(149) For an application identical to that of example 1, the performance was compared of two installations conforming to the variant ULG and two installations conforming to the variant UL, with in each of the variants one of the installations operating under the conditions of Example 1 and the other under different conditions set cut in the table below.

(150) TABLE-US-00009 Example 1 Example 2 G.sub.M 1,1,1,3,3,3- n-pentane hexafluoropropane G.sub.R tetrafluoroethane isobutane Hot source 65 C. 94.2 C. T.sub.hM COP.sub.4 ULG 0.34 0.51 COP.sub.4 UL 0.56 0.36

(151) Thus using isobutane as the receiving working fluid and n-pentane as the driving working fluid, with the same objective of producing cold at 12 C. but having a hot source at 94.2 C. (T.sub.hm), the coefficients of performance of the variants UL and ULG become COP.sub.4 (UL)=0.36 and COP.sub.4(ULG)=0.51, respectively, which result has to be compared with the maximum coefficient of performance, which would be COP.sub.c4=0.89 under the conditions of Example 2. It is thus apparent that, under the conditions of Example 2, the variant ULG performs best, although it is more complex.

Example 3

(152) The objective here is habitat heating using heat supplied by plane solar panels as primary heat and amplifying it by means of an installation operating in the HT driving/LT receiving mode. The fluids adopted are the same as in Example 1, i.e. HFC R-236fa for the driving working fluid and HFC R-134a for the receiving working fluid.

(153) The thermodynamic constraints are identical to those of Example 1, namely: the temperature T.sub.hM (produced by the plane solar panels) is equal to 65 C.; the temperature T.sub.bR of the R134a in the evaporator E.sub.R is set at 12 C., which temperature is compatible with extraction of geothermal heat in winter outside the house to be heated.

(154) With these constraints and given the liquid/vapor equilibrium of these working fluids as shown in FIG. 3, the other temperature and pressure conditions are identical to those of Example 1, namely: high pressure P.sub.h=8.69 bar, low pressure P.sub.b=4.43 bar; temperatures of release of heat in the condensers C.sub.R and C.sub.M T.sub.bM=40.3 C. and T.sub.hR=34.3 C., which are temperatures compatible with supply of heat within the habitat by means of underfloor heating.

(155) A quadrithermal Carnot machine operating between the same temperatures T.sub.hM, T.sub.bM, T.sub.bR, T.sub.hR would have an ideal coefficient of amplification COA.sub.c4=1.93.

(156) The coefficient of amplification of the quadrithermal installation operating under steady conditions in the variant UL that offers the best performance under these conditions has COA.sub.4(UL)=1.56.

(157) For this application, the ratio COA.sub.4(UL)/COA.sub.c4 is even better (80%).

(158) Thus using a reversible heat pump of this kind, the same installation of the invention may exercise the functions of cooling in summer (Examples 1 and 2) and (with amplification) heating in winter (the present Example 3) with excellent performance in terms of COP and COA compared to the current state of the art.

Example 4

Exploitation of Waste Heat

(159) In this application the aim is to use a trithermal installation of the invention operating in the HT receiving/LT driving mode to exploit waste heat (i.e. lost heat) at a temperature of 105 C., i.e. T.sub.hM=T.sub.bR=105 C. The working fluids used are HC n-pentane for the driving working fluid and water for the receiving working fluid.

(160) With this constraint, and given the liquid/vapor equilibrium of these fluids (see FIG. 3), the following other temperatures and pressures are obtained: high pressure P.sub.h 6.62 bar and low pressure P.sub.b=1.21 bar; waste heat temperature in the condenser C.sub.M: T.sub.bM 41.3 C., compatible with evacuation to the outside air even in summer; temperature at which heat is supplied to the condenser C.sub.R: T.sub.hR=162.7 C., much higher than the waste heat temperature (105 C.) and thus susceptible to exploitation.

(161) A trithermal Carnot machine operating between the same temperatures T.sub.hM(=T.sub.hR), T.sub.bM, and T.sub.hR would have an ideal coefficient of amplification COA.sub.c3=0.605.

(162) The coefficient of amplification of the trithermal installation operating under steady conditions in the variant UL is COA.sub.3(UL)=0.292.

(163) For this application, the ratio COA.sub.3(UL)/COAC.sub.3 is also very good (48%). Moreover, there is no standard heat pump (using mechanical compression of vapor), which in the current state of the art makes it possible to produce a rise in temperature to this level.