EP3658835A1

EP3658835A1 - Refrigeration plant

Info

Publication number: EP3658835A1
Application number: EP18758929.6A
Authority: EP
Inventors: Thomas Vinard; Sébastien BUR; Jérôme Girard
Original assignee: Alpinov X
Current assignee: Alpinov X
Priority date: 2017-07-28
Filing date: 2018-07-25
Publication date: 2020-06-03
Also published as: FR3069624B1; US20210156603A1; JP2020535382A; AU2018307454B2; FR3069624A1; AU2018307454A1; EA039194B1; CN111094879B; CN111094879A; BR112020001728A2; BR112020001728B1; WO2019020940A1; JP7158476B2; KR102539042B1; KR20200047541A; CA3069841A1; US11747069B2; EA202090341A1

Abstract

The invention relates to a refrigeration plant (5) comprising: a first chamber (10) containing water in the liquid state (14) at a temperature below or equal to the temperature of the triple point of water or less than 10°C above the temperature of the triple point of water and water in the gaseous state (11) at a first pressure equal to the saturation vapour pressure of water in equilibrium with the pressure of the water in the liquid state (14); a second chamber (30) at a second pressure strictly greater than the first pressure by at least a factor of two; a compression device (32) connecting the first chamber to the second chamber; a condensation device (34) suitable for condensing water in the gaseous state in the second chamber into water in the liquid state; and a device (24) for extracting cold power in the first chamber.

Description

REFRIGERATING INSTALLATION

The present patent application claims the priority of the French patent application FR17 / 57207 which will be considered as an integral part of the present description.

Field

The present application relates to a refrigeration plant.

Presentation of the prior art

A refrigeration system can be used in many different applications.

An example of the use of a refrigeration installation relates to an air conditioning system, particularly in the context of a district cooling network or for a data center.

Another example of the use of a refrigeration installation concerns an artificial snow production system, for example for the snow-making of ski resorts in the case of light snowfall due to weather conditions or inherent to the geographical situation of the ski resorts. .

In general, for any thermomechanical energy converter, and especially for a refrigeration plant, the coefficient of performance (COP) is the ratio between the thermal power produced by the system (heat quantity hot Q _Q ^ OR amount of cold heat Q _re f) ^e t work provided to the system (work W). It is generally desirable that the COP be as high as possible, which reflects a good energy efficiency of the system and induces a low energy consumption, knowing that the energy consumption includes the power consumption of the system.

There are various types of refrigeration systems that can be used in particular artificial snow production systems. The first artificial snow production systems are systems open to ambient air, such as snow cannon or snow boom, and generally involve the spraying of a mixture of water and air which crystallizes at the same time. contact with ambient air. The air can come from a source of compressed air whose relaxation causes the formation of snow. A disadvantage of these systems is that they can only operate in reduced temperature and humidity ranges, generally at a temperature below -2 ° C and at a humidity greater than 30%. Second artificial snow production systems comprise open systems, as described in the patent application WO2012 / 104787. The power consumption of such snow production systems typically ranges from 20 kWh to 40 kWh per cubic meter of snow produced, which is lower than the second and third snow production systems. However, such production systems require the construction of cooling towers and therefore have a construction cost too high for large-scale operation.

Third artificial snow production systems include refrigerator-type closed systems including a compressor, a condenser, a pressure reducer and an evaporator. A disadvantage is that the COP is generally low, generally in the range of 2 to 4. In addition, the power consumption of such snow production systems can be high, for example from 40 kWh to 120 kWh per cubic meter of snow produced.

Fourth artificial snow production systems comprise closed systems employing cryogenic processes including in particular the formation of a mixture of water and a cryogenic gas, in particular nitrogen or carbon dioxide. Even though the COP of such a snow production system may be high, the energy required to produce the cryogenic fluid must be taken into account. As a result, the overall consumption of such snow-making systems can be greater than several hundred kWh per cubic meter of snow produced, resulting in an operating cost that is too high for large-scale operation and significant constraints. logistics.

It would be desirable to provide a cold production plant, particularly for an air conditioning system or for an artificial snow production system, having a high COP, especially greater than 6, preferably greater than 10, and whose electrical consumption is low, especially when the cooling plant is installed in a snow production system whose consumption is less than 5 kWh, preferably less than 3 kWh per cubic meter of snow produced. It would further be desirable for the refrigeration plant to be able to operate normally over a wide range of ambient temperatures, particularly at positive temperatures, and preferably up to 25 ° C or even up to 35 ° C. summary

Thus, an object of an embodiment is to overcome at least in part the disadvantages of refrigeration installations described above.

Another object of an embodiment is that the COP of the refrigeration plant is greater than 6, preferably greater than 10.

Another object of an embodiment is that the electrical consumption of the refrigerating plant is reduced, in particular, when the cooling plant is installed in a snow production system, less than 5 kWh per cubic meter of snow produced, preferably less than 3 kWh per cubic meter of snow produced.

Another object of one embodiment is that the refrigeration plant can operate at an ambient temperature of -30 ° C to + 25 ° C, preferably -30 ° C to + 35 ° C.

Another object of an embodiment is that the construction cost of the refrigeration plant is reduced.

Thus, an embodiment provides a refrigeration plant comprising:

a first chamber containing water in the liquid state at a temperature less than or equal to the temperature of the triple point of water or greater than the temperature of the triple point of water of less than 10 ° C, preferably less than 5 ° C, and water in the gaseous state at a first pressure equal, within 10%, to the saturation vapor pressure of the water in equilibrium with the pressure of the water at liquid state in the first chamber, in particular equal to 10%, at the saturation vapor pressure of the water at the temperature of the triple point of the water;

a second chamber at a second pressure which is strictly greater than the first pressure by at least a factor of two;

a compression device connecting the first enclosure to the second enclosure;

a condensation device housed partly in the second chamber and adapted to condense the water in the gaseous state in the second chamber with water in the liquid state; and

a cold power extraction device in the first enclosure.

According to one embodiment, the installation comprises a device for heating the water in the gaseous state in the first chamber intended to feed the compression device. According to one embodiment, the first chamber further contains water in the solid state at a temperature less than or equal to the temperature of the triple point of water.

According to one embodiment, the water circulates in a closed circuit in the installation.

According to one embodiment, the condensation device comprises a first heat exchanger outside the second enclosure and means for circulating a first heat transfer fluid around the second enclosure through the first heat exchanger.

According to one embodiment, the first coolant is the ambient air or water of a stream, a body of water or a body of water.

According to one embodiment, the second pressure in the second chamber is less than or equal to 10000 Pa (100 mbar), preferably less than or equal to 6000 Pa (60 mbar).

According to one embodiment, the cold power extraction device comprises a hydraulic circuit in which circulates a portion or all of the water in the liquid state present in the first chamber, the hydraulic circuit comprising a second heat exchanger located outside the first enclosure.

According to one embodiment, the cold power extraction device comprises a closed hydraulic circuit in which a second heat transfer fluid circulates, the hydraulic circuit comprising a second heat exchanger located outside the first enclosure and a third heat exchanger. heat disposed in the first enclosure.

According to one embodiment, the refrigerating installation comprises a third enclosure in which is located the second heat exchanger delivering the cold power to the end user, the third enclosure containing for example water in the solid state. According to one embodiment, the heating device comprises a source of infrared radiation and / or a source of microwave radiation.

According to one embodiment, the heating device is adapted to heat the water in the gaseous state in the first chamber intended to supply the compression device with at least 2 ° C., preferably at least 10 ° C. more preferably at least 20 ° C.

According to one embodiment, the compression device comprises at least one turbomachine type compressor, in particular a centrifugal compressor and / or an axial compressor.

According to one embodiment, the compression device comprises a succession of stages, each stage comprising a rotor and a stator.

According to one embodiment, the compression device is a Tesla compressor.

According to one embodiment, the compression device comprises a fixed compression ratio first compressor stage and a controllable compression ratio compressor second stage.

According to one embodiment, the refrigerating installation further comprises, in the first enclosure, a mechanical device for protecting the compression device against the admission of particles in the solid and / or liquid state.

According to one embodiment, the refrigerating installation comprises a liquid supply pipe in the liquid state in the first enclosure.

According to one embodiment, the condensation device comprises at least one nozzle for projecting water droplets in the liquid state in the second chamber.

According to one embodiment, the installation further comprises a system for regulating the pressure difference between the second enclosure and the first enclosure.

According to one embodiment, the control system comprises an expansion turbine configured to relax water in the gaseous state from the second chamber and discharge a mixture containing water in the gaseous state and water in the liquid state in the first chamber.

According to one embodiment, the first enclosure comprises at least one water reservoir in the liquid state and in which said mixture is discharged into the water in the liquid state contained in said reservoir.

One embodiment also provides an artificial snow production system comprising a refrigeration plant as defined above.

One embodiment also provides an air-conditioning system for industrial, collective and private installations comprising a refrigeration installation as defined above, especially in the context of a district cooling network or for a data center.

An embodiment also provides a method for producing cold comprising the steps of:

bringing liquid in the first chamber to a liquid at a temperature less than or equal to the temperature of the triple point of water or greater than the temperature of the triple point of water of less than 10 ° C, preferably less than 5 ° C, and form water in the gaseous state at a first pressure equal, within 10%, to the saturation vapor pressure of the water in equilibrium with the pressure of the water at the liquid state in the first chamber, in particular equal to 10% at the saturation vapor pressure of the water;

compressing water in the gaseous state of the first chamber to a second chamber at a second pressure strictly at the first pressure at least a factor of two;

condensing the water in the gaseous state in the second chamber with water in the liquid state; and

extract cold power into the first enclosure. According to one embodiment, the method further comprises the step of heating the water in the gaseous state in the first chamber intended to be compressed.

Brief description of the drawings

These and other features and advantages will be set forth in detail in the following description of particular embodiments in a non-limiting manner with reference to the accompanying drawings in which:

Figure 1 is a partial sectional and schematic view of an embodiment of a refrigeration plant;

Figures 2 to 4 show enthalpy pressure diagrams of water illustrating the operation of the refrigeration plant shown in Figure 1;

Figure 5 is a partial sectional and schematic view of a more detailed embodiment of a portion of the refrigeration plant of Figure 1;

Figures 6 and 7 are partial sectional and schematic views of more detailed embodiments of another part of the refrigeration plant of Figure 1;

Figure 8 is a partial sectional and schematic sectional view of another embodiment of a refrigeration plant;

Figure 9 is a partial sectional and schematic view of a more detailed embodiment of a portion of the refrigeration plant of Figure 8; and

Figure 10 is a partial sectional and schematic sectional view of another embodiment of a refrigeration plant.

detailed description

For the sake of clarity, the same elements have been designated by the same references in the various figures and, in addition, the various figures are not drawn to scale. In addition, only the elements useful for understanding the present description have been shown and are described. In particular, compressors and heat exchangers are well known to those skilled in the art and are not described in detail. In the following description, when reference is made to relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to qualifiers for orientation, such as the terms "horizontal", "vertical", etc., reference is made to the orientation of the figures or to a refrigeration plant in a normal position of use. In the remainder of the description, unless otherwise indicated, the terms "substantially", "about",

"approximately" and "of the order of" mean "to within 10%", preferably "to within 5%".

In the rest of the application, the term "water" is the chemical compound ¾ () which may be in the liquid, solid or gaseous state. In addition, the terms "water in the gaseous state" or "water vapor" are subsequently used interchangeably. In the remainder of the application, the expression "liquid water" or "water in the liquid state" is used to designate indifferently pure water in the liquid state or water in the liquid state corresponding to the solvent of an aqueous solution containing in addition at least one solute. In addition, in the following description, the expression "triple point of water" means "triple point of pure water".

Embodiments of refrigeration plants using water in the liquid state will now be described. It is clear that, in these embodiments, the water in the liquid state may correspond to the solvent of an aqueous solution, that is to say that additives may be added to the water in the state liquid.

FIG. 1 represents an embodiment of a refrigerating installation 5.

The refrigerating plant 5 comprises:

a first enclosure 10 at low pressure, gas-tight with respect to the external medium and thermally insulated relative to the external environment, the first enclosure 10 at low pressure containing, in operation, essentially water vapor 11;

a tank 12 containing liquid water 14, and, during stationary operation of the refrigeration plant 5, water in the solid state 15, the tank 12 being located in the first chamber 10 to low pressure and being open on the internal volume of the first enclosure 10 at low pressure;

a pipe 18 for supplying liquid water into the reservoir 12;

a protective element 20, housed in the first low-pressure enclosure 10, covering the free surface of the liquid water 14 and preventing splashing of liquid water from the reservoir 12;

at least one heater 22 of at least a portion of the water vapor in the first low pressure vessel 10;

a device 24 for extracting cold power in the reservoir 12, for example a solid state water recovery device connected to the reservoir 12;

a second chamber 30 at low pressure, gas-tight with respect to the external medium and thermally insulated relative to the external medium, the pressure in the second chamber 30 at low pressure being greater than the pressure in the first chamber 10 at low pressure;

a compressor 32, also called compression device, for example a turbocharger, a turbine or a Tesla compressor, connecting the first enclosure 10 at low pressure to the second chamber 30 at low pressure, receiving strictly the water vapor of the first low pressure chamber 10 providing compressed water vapor to the second low pressure chamber 30;

a condensation device 34, also called a condenser 34, adapted to liquefy the water vapor present in the second low-pressure chamber 30, the condenser 34 being partially housed in the second chamber 30 at low pressure and comprising for example a heat exchanger cooled by the ambient air, the condenser 34 comprising means, for example a fan 36, for circulating ambient air through The heat exchanger;

a pipe 38 for recovering the liquid water produced by the condenser 34; and

a processing module 40 connected to the heating device 22, to the compressor 32 and to the condenser 34 and adapted to control the heating device 22, the compressor 32 and the condenser 34.

When the refrigeration plant 5 operates in an open cycle, the liquid water 14 contained in the tank 12 may be water coming directly from the running water supply system, or fresh water, in particular water from a watercourse or water from a hillside reservoir. In the case where the refrigeration system 5 operates in a closed cycle, the pipe 38 may be connected to the pipe 18. The refrigeration system 5 may further comprise a system 42 for regulating the pressure difference between the second enclosure 30 at low pressure and the first enclosure 10 at low pressure. The system 42 may correspond to a controlled valve system, a capillary system, an expansion turbine system or an overflow system, and is adapted to maintain the pressure difference between the second low pressure vessel 30 and the first enclosure 10 at low pressure to a substantially constant value.

The processing module 40 may correspond to a dedicated circuit or may comprise a processor, for example a microprocessor or a microcontroller, adapted to execute instructions of a computer program stored in a memory. The refrigerating installation 5 may further comprise sensors, in particular temperature sensors, pressure sensors, level sensors, flow sensors, etc., not shown, connected to the processing module 40, in particular to the detection of the temperature and the pressure in the enclosures 10 and 30.

According to one embodiment, the compressor 32 is an axial compressor or a centrifugal compressor which provides a vapor flow substantially compressed along the axis of rotation of the compressor. The compressor comprises a succession of compression stage, each stage comprising a rotor and a stator. The rotor comprises vanes driven in rotation by a transmission shaft. The rotor accelerates the gas flow thanks to the energy transmitted by the compressor drive shaft. The stator includes fixed vanes. The stator transforms the kinetic energy of the gas flow into pressure via the shape of the stator.

The heater 22 is preferably a radiant heater comprising a source of electromagnetic radiation reaching the water vapor. The heating device 22 comprises, for example, a system for heating the water vapor by infrared or for example a system for heating the water vapor by microwave. According to one embodiment, the heating device 22 comprises both a source of infrared radiation and a source of radiation by microwave. Depending on the intended application, the heater 22 may not be present.

The dimensions of the refrigerating installation 5 depend on the intended application. The volume of the first chamber 10 at low pressure can be between 1 1 and several thousand cubic meters, in particular between 10 1 and 10000 1. The volume of the second chamber 30 at low pressure can be between 1 1 and a thousand cubic meters, especially between 1 1 and 10000 1. The volume of liquid water 14 in the reservoir 12 can be between 1 1 and several thousand cubic meters, in particular between 1 1 and 3000 m ^, in particular between 9 1 and 9999 1. The refrigeration system 5 comprises a primary vacuum pump, not shown, connected to the first low-pressure enclosure 10 and / or the second low-pressure enclosure 30.

FIG. 2 represents an enthalpy-pressure diagram of the water illustrating the operation of the refrigerating installation 5 at the beginning of its operation.

The points referenced A to G in FIG. 2 illustrate successive states through which water flowing in the refrigerating installation 5 passes.

The point A represents liquid water that will be introduced into the tank 12 through the pipe 18, for example to fill the tank 12 at the beginning of the operation of the installation 5. The pressure of the liquid water at point A is at a first pressure value and the temperature of the liquid water at point A is at a first temperature value. According to one embodiment, the first pressure value is greater than or equal to 0.1 MPa (1 bar), for example greater than or equal to 0.1 MPa (1 bar) and less than or equal to 10 MPa (100 bar) . According to one embodiment, the first temperature value is greater than or equal to 5 ° C, for example greater than or equal to 5 ° C and less than or equal to 10 ° C. The water supplied into the reservoir 12 comes, for example, from a water distribution network to which the refrigerating installation 5 is connected. The first temperature value can then correspond to the temperature of the water supplied by the distribution network. .

Once introduced into the reservoir 12, the pressure of the liquid water 14 decreases from the first pressure value to the pressure in the first low pressure vessel 10 which is at a second pressure value. This corresponds to the transition from point A to point B. In operation, the second pressure value is equal to the saturated vapor pressure of the liquid water 14 present in the reservoir 12. According to one embodiment, the second value of pressure in the first chamber 10 at low pressure is typically between 600 Pa (6 mbar) and 2500 Pa (25 mbar), preferably between 600 Pa (6 mbar) and 1500 Pa (15 mbar). By way of example, for water at 5 ° C., the pressure in the first low-pressure enclosure 10 may be 870 Pa (8.7 mbar). The temperature of the liquid water introduced into the reservoir 12 during the pressure drop remains substantially constant and equal to the first temperature value.

The temperature of the liquid water 14 in the reservoir 12 is at a second temperature value. At the beginning of the operation of the refrigerating plant 10, the second temperature value is substantially equal to the first temperature value so that the temperature of the water introduced into the reservoir 12 and whose pressure has decreased does not vary substantially.

There is evaporation of a portion of the liquid water 14 in the tank 12 which will bring the water from the first temperature value to the second temperature value. This corresponds to the transition from point B to point C. Since the pressure in the low pressure chamber 10 is equal to the saturation vapor pressure of the water at the second temperature value, the vaporization is a boiling of the liquid water 14 which comprises in particular the formation of bubbles 43 (see Figure 1) in the liquid water 14. It is then obtained, in the first chamber 10 at low pressure, water vapor at the second temperature value and at the second pressure value. The protection element 20 makes it possible to prevent splashes of liquid water from reaching the compressor 32 or liquid water from spilling out of the tank 12 during the boiling of the liquid water 14. L Protective element 12 may, in addition, make it possible to increase the exchange surface by including parts penetrating into the liquid water.

According to one embodiment, all or part of the water vapor in the first low-pressure enclosure 10 is heated by the heating device 22. The temperature of a portion of water vapor in the first enclosure 10 at low pressure then changes from the second temperature value to a third value temperature. According to one embodiment, the steam is pumped by the compressor 32 into the part of the first chamber 10 where it is heated. This corresponds to the transition from point C to point D. According to one embodiment, the third temperature value is greater than or equal to 0 ° C. and less than or equal to 100 ° C. Preferably, the third temperature value is greater than the second temperature value of at least 2 ° C, preferably at least 10 ° C, more preferably at least 20 ° C. The pressure of the water vapor during the heating step does not vary substantially and remains substantially equal to the second pressure value. The use of the heating device 22 by radiation makes it possible to heat all the water vapor which supplies the compressor 32. In fact, it would be difficult with a conduction or convection heating device to heat all the water vapor that supplies the compressor 32 due to the low pressure and consequently the density of material too low in the first chamber 10 at low pressure.

The water vapor heated to the third temperature value supplies the compressor 32 which delivers the compressed steam to the second low pressure vessel 30. This corresponds to the transition from the point D to the point E. According to one embodiment, the compression ratio of the compressor 32 is greater than or equal to 2 and for example less than or equal to 14. The pressure in the second enclosure 30 at low pressure is equal to a third pressure value greater than the second pressure value by at least a factor of 2. For example, the third pressure value is greater than or equal to 600 Pa (6 mbar) and less than or equal to at 10000 Pa (100 mbar), preferably less than or equal to 6000 Pa (60 mbar). By way of example, when the second pressure value is 870 Pa (8.7 mbar) and the compression ratio of the compressor 32 is equal to 2, the third pressure value is substantially equal to 1740 Pa (17 , 4 mbar). The compression of the water vapor by the compressor 32 causes a heating of the water vapor whose temperature changes from the third temperature value to a fourth temperature value, greater than the third temperature value.

The water vapor compressed in the chamber 30 at low pressure is cooled and then liquefied in liquid water cooled by the condenser 34. This corresponds to the transition from the point E to the point F and to the transition from the point F to the point G. water pressure during the cooling and liquefying step does not vary substantially and remains equal to the third pressure value. The temperature of the water varies from the fourth temperature value to a fifth temperature value strictly below the fourth temperature value. By way of example, for a third pressure value equal to 1740 Pa (17.4 mbar), the fifth temperature value may be equal to 15.3 ° C. The higher the compression ratio, the more it is possible to condense the water with high outside temperatures and the faster the condensation can be achieved.

The liquid water produced by the condenser 34 is discharged from the tank 30 at low pressure through the pipe 38. In the case of a closed cycle, the pipe 38 is connected to the pipe 18 so that the liquid water removed from the enclosure 30 is returned to the reservoir 12.

Condensation causes vacuum pumping, related to the difference in mass volume between the liquid water and the carbonated water (ratio of about 1600 to 200000 between the liquid and gaseous phases), which maintains a vacuum level in the chambers 10 and 30. The maintenance of the pressure difference between the low pressure chamber 30 and the low pressure chamber 10 is carried out by the processing module 40 which controls the heating device 22, the compressor 32, for this purpose. the condenser 34, the system 42 and possibly the primary vacuum pump.

The primary vacuum pump operates at the start of the refrigeration plant 5 until the pressure in the first low pressure vessel 10 reaches the saturation vapor pressure at the first temperature value. The pump The vacuum can then be stopped and the pressure in the chamber 10 is maintained by the depression generated at the condenser 34 and the mechanical work of the compressor 32. The vacuum pump can also participate, if necessary, in maintaining the pressure in the chamber. the first enclosure 10 at low pressure.

FIGS. 3 and 4 each represent an enthalpy-pressure diagram of the water illustrating the operation of the refrigeration plant 5 under steady state conditions respectively for an open cycle and for a closed cycle.

Under stationary conditions, the reservoir 12 is filled with liquid water 14. Additional water is supplied via line 18 into reservoir 12 to compensate for the losses of liquid water from reservoir 12, for example continuously or intermittently . In the case of an open cycle, the additional water is at point A (Figure 3). In the case of a closed cycle, the liquid water supplement comes from the condensates recovered in the chamber 30 and is therefore at point G.

During the evaporation of the liquid water 14 from the tank 12 described above, the heat required to produce water vapor is extracted from the liquid water 14 since the first low pressure enclosure 10 is thermally insulated by relative to the external environment. A cooling of the liquid water 14 in the reservoir 12 is thus obtained. This is shown in FIGS. 3 and 4 by an additional state represented by the point B 'in the succession of states followed by the water circulating in the atmosphere. In fact, when water is introduced into the tank 12 at the first temperature value and at the first pressure value for an open cycle (point A in FIG. 3) and at the fifth temperature value and third pressure value for a closed cycle

(point G in Figure 4), there is a decrease in the pressure of this water to the second pressure value, corresponding to the transition from point A to point B, and a decrease in the temperature of the water of the first temperature value at the second temperature value, strictly less than the first temperature value corresponding to the transition from point B to point B '.

The pressure in the first chamber 10 at low pressure decreases simultaneously with the decrease in the temperature of the liquid water 14 of the reservoir 12 to remain equal to the saturation vapor pressure at the temperature of the liquid water 14 in the reservoir 12. Maintaining the pressure in the chamber 10 at the saturation vapor pressure at the temperature of the liquid water 14 in the tank 12 is achieved by the processing module 40 which controls for this purpose the heating device 22, the compressor 32 and the condenser 34, the system 42 and possibly the primary vacuum pump.

According to one embodiment, the temperature of the liquid water 14 in the reservoir 12 decreases until reaching the temperature of the triple point of the water, which, for example, for a pressure of 611 Pa (6, 11 mbar) is 0.01 ° C. Ice crystals 15 are then formed in the reservoir 12, which corresponds to the transition between points B 'and B "in FIGS. 3 and 4. According to one embodiment, in stationary mode, the temperature of the water liquid 14 in the tank

12 remains substantially constant and equal to the temperature of the triple point of pure water and the pressure in the first chamber 10 at low pressure is substantially equal to the saturation vapor pressure at the temperature of the triple point of water. According to another embodiment, when means for mixing the water are provided or when appropriate additives are added to the water, in a steady state, the temperature of the liquid water 14 in the tank 12 remains substantially constant and equal to a temperature below the temperature of the triple point of pure water and the pressure in the first chamber 10 at low pressure is substantially equal to the saturation vapor pressure of the water in equilibrium with the pressure of the water at the liquid state at the temperature below the temperature of the triple point of the water. The water is then present in the first chamber 10 at low pressure simultaneously in the gaseous state, in the liquid state and in the the solid state. According to another embodiment, especially when the refrigerating plant is used in an air-conditioning system, the temperature of the liquid water 14 in the tank 12 decreases to a temperature greater than the temperature of the triple point of the water less than 10 ° C, preferably less than 5 ° C. The water is then present in the first chamber 10 at low pressure simultaneously in the gaseous state and in the liquid state.

In summary, the evaporation of a mass M _ev of water will contribute to cooling the mass M _] _-j_q of water remaining at the second temperature value, then to solidify a mass M _so] _ of water, possibly zero, which then turns into ice according to the following relation (1):

Me _V * L _ev = M _liq * C _p * ΔΘ + M _sol * L _sol (1) where L _ev is the latent heat of evaporation of water, Cp is the heat capacity of liquid water, ΔΘ is the difference between the first and second temperature values, and L _so] _ is the latent heat of solidification of the water.

In the case where water in the solid state is produced, at the end of the cycle, it is possible to have an ice mass M _so] according to the following relation (2):

Me _V * L _ev = M _sol * (C _p * ΔΘ + L _sol ) (2) The other transitions of states of water are the same as those previously described in relation to Figure 2. In particular, the heating step which corresponds to the transition between points C and D is intended to increase the temperature of the water vapor in the enclosure 10 at low pressure by at least 2 ° C, preferably at least 10 ° C preferably at least 20 ° C. In addition, when the temperature of the liquid water 14 in the reservoir 12 is reduced, the compression ratio of the compressor

32 may be adjusted to retain substantially the same third pressure value in the second low pressure vessel 30. For example, when the second pressure value in the first enclosure 10 at low pressure is 611 Pa (6.11 mbar), the compression ratio of the compressor 32 is for example equal to 3 and the third pressure value in the second chamber 30 at low pressure is 1830 Pa (18.3 mbar). By way of example, the fifth value of the temperature of the liquid water produced by the condenser 34 at 1830 Pa (18.3 mbar) is, for example, equal to 16.05 ° C. for an ambient temperature of approximately 6 ° C. C.

According to one embodiment, the cold power extraction device 24 removes the ice crystals 15 as they form in the tank 12. The subsequent use of the ice crystals depends on the intended application .

For an application for the production of artificial snow, the ice crystals are recovered to produce artificial snow. There may be provided a refrigeration system for lowering the temperature of the recovered ice and / or a pumping unit to evaporate the residual water and thereby cool and dry the ice. In addition, it is possible to provide a chopping and aeration device for the ice produced.

For an application for air conditioning or refrigeration and for the production of artificial snow, the ice crystals present in the tank 12 can act as a cold source.

The condenser 34 is adapted to liquefy the water vapor in the second chamber 30 at low pressure by a heat exchange between the water vapor in the second chamber 30 at low pressure and a refrigerant. According to one embodiment, the refrigerant is the air outside the refrigeration plant 5. The condenser 34 may comprise air stirring means, for example the fan coil 36 as shown in FIG. Figure 1, the air mixing is shown schematically by the arrow 44. Alternatively, the condenser 34 may comprise a venturi effect fan or a thermosiphon. According to another embodiment, the condenser 34 may comprise a heat exchanger group liquid-water vapor in the chamber 30 and a liquid-air or liquid / liquid exchanger group outside the chamber 30, the cooling fluid flowing between these two exchangers.

Advantageously, the condensation of the water in the enclosure 30 does not require the implementation of a refrigerating machine.

The production of liquid water by the condenser 34 can be carried out by using ambient air as soon as the ambient air temperature is below the desired fifth temperature value. In the example described above in which the condenser 34 produces liquid water at 16.05 ° C., the ambient air can be used as soon as its temperature is below 16 ° C., preferably below 6 ° C. for obtain a temperature difference of at least 10 ° C on the exchanger.

The maximum possible ambient air temperature allowing ambient air to be used as coolant by the condenser 34 is in particular fixed by the compression ratio of the compressor 32. With a compression ratio of 10, it can be envisaged a pressure saturating steam of 6000 Pa (60 mbar) in the second chamber 30 at low pressure and a fifth temperature value of 36 ° C, which can be obtained without difficulty as soon as the ambient air temperature is less than 30 ° C. Preferably, the refrigeration plant 5 can be used as soon as the ambient temperature is lower than 20 ° C for the production of artificial snow and less than 35 ° C for air conditioning.

According to one embodiment, the theoretical COP of the refrigeration plant 5 is of the order of 19 to 20.

Table I below shows, for an application to the production of artificial snow, and as a function of the ambient air temperature, the electrical consumption, expressed in kilowatts per cubic meter of snow produced, of the refrigerating plant 5 (INV) shown in FIG. 1, a snow gun type installation (AA1), a snow boom type installation (AA2), a low-evaporation installation (AA3). pressure between 0.01 MPa (100 mbar) and 0.02 MPa (200 mbar) and a refrigerator-type installation (AA4).

Table I

The electrical consumption per cubic meter of snow produced by the refrigerating plant 5 (INV) is much lower than that of refrigerator refrigeration units (AA4) and with low pressure evaporation between 0.01 MPa (100 mbar) and 0, 02 MPa (200 mbar) (AA3).

According to one embodiment, the liquid water supplied by the condenser 34 is not reused. According to another embodiment, the water supplied by the condenser 34 is reused for supplying the reservoir 12.

FIG. 5 is a partial schematic view of a more detailed embodiment of the low-pressure tank 10 of the refrigeration plant 5 of FIG. 1.

According to one embodiment, the protective element 20 comprises a membrane or a screen 46 covering the free surface of the liquid water 14. The membrane or the screen 46 is permeable to water vapor and substantially watertight. liquid water. The protective element 20 may further comprise elements immersed in liquid water 14, not shown, and which make it possible to regulate the generation of bubbles 43 during the boiling of the liquid water 14.

According to one embodiment, baffles 48 may be arranged in the part of the enclosure 10 in which the water vapor is heated by the heating device 22. The baffles 48 make it possible to lengthen the path of the steam. water until the inlet of the compressor 32 to obtain the heating of the steam to the desired temperature.

FIG. 6 is a sectional, partial and schematic view of a more detailed embodiment of the device 24 for recovering the solid state water of the refrigeration plant 5.

In the present embodiment, the device 24 is adapted to extract the water in the solid state of the reservoir 12. Such an embodiment is particularly suitable in the case where the refrigerating plant 5 is used for the production of snow artificial.

The device 24 may comprise a secondary enclosure 50 connected to the reservoir 12 by a low pipe 52 and a high pipe 54, located above the lower pipe 52. A pump 56 provided on the high pipe 54 is adapted to circulate the contents. from the reservoir 12 to the secondary enclosure 50 and a pump 58 provided on the lower pipe 52 is adapted to circulate the contents of the secondary enclosure 50 to the reservoir 12. The pressure in the secondary enclosure 50 may be higher than in the reservoir 12, for example equal to the atmospheric pressure, so that there is no boiling in the secondary enclosure 50. The ice crystals accumulate then over the liquid water 62 by settling in a floating cluster of ice 60. The device 24 comprises means 64 for extracting the ice crystals 60, comprising for example a worm or a bucket elevator.

FIG. 7 is a partial schematic cross-sectional view of another more detailed embodiment of the device 24. The device 24 may be part of an air-conditioning or refrigeration system, and may comprise a closed circuit in which circulates a refrigerant and comprising a first heat exchanger 66 disposed in the reservoir 12 and a second heat exchanger 68 located outside the enclosure 10. According to another embodiment, the first heat exchanger 66 does not is not present and the flowing liquid in the heat exchanger 68 corresponds to the liquid water 14 present in the reservoir 12.

FIG. 8 is a sectional, partial and schematic view of an embodiment of a refrigerating installation 70. The refrigerating installation 70 comprises all the elements of the refrigerating installation 5 represented in FIG. it further comprises means for maintaining the liquid water supercooled in the first enclosure 10 at low pressure. According to one embodiment, the means for maintaining the supercooled liquid water may comprise an agitator 72 adapted to stir the water in the liquid state in the first enclosure 10 at low pressure. The agitator 72 comprises, for example, a bar or a propeller rotated in water in the liquid state. According to another embodiment, the means for maintaining the supercooled liquid water may comprise at least one additive added. with water in the liquid state. This additive mixed with water, leads to a solution whose solidification temperature is below the solidification temperature of the water without additive.

In the present embodiment, the temperature of the liquid water 14 in the first low-pressure chamber 10 may be less than the temperature of the triple point of the water, and is for example at a temperature which may vary from -40 ° C. C. at -1 ° C., preferably from -20 ° C. to -1 ° C. The operation of the refrigeration system 70 is identical to the operation previously described for the refrigeration plant 5 except that the temperature of the liquid water in the first low-pressure chamber 10 may be lower than the temperature of the triple point of the refrigeration system. 'water.

FIG. 9 is a partial schematic sectional view of a more detailed embodiment of a portion of the refrigeration plant of FIG. 8, in which the device 24 for extracting cold power in the tank 12 to the structure shown in FIG. 7. The second heat exchanger 68 of the device 24 is located in an enclosure 80 containing the water in the liquid state 82 and is used to cool the water in the liquid state 82 to obtain, in the chamber 80, water in the solid state 84. The pressure in the enclosure 80 may advantageously be greater than the saturation vapor pressure of the water at the temperature of the triple point of the water, and be, for example, at atmospheric pressure. According to another embodiment, the first heat exchanger 66 is not present and the liquid circulating in the heat exchanger 68 corresponds to the liquid water 14 present in the reservoir 12.

FIG. 10 is a sectional, partial and schematic view of an embodiment of a refrigerating installation 90. The refrigerating installation 90 comprises all the elements of the refrigerating installation 5 represented in FIG. that the single tank 12 of the refrigeration plant 5 is replaced by N tanks 12] _ located in the first enclosure 10 at low pressure, N being an integer ranging from 1 to 100. The conduit 18 for water supply is connected to each tank 12] _12- ^. The use of several tanks 12 to 12 allows, in a simple way, to increase the surface of the liquid / vapor interface for the same volume of liquid water with respect to a single tank. In addition, the agitation of the liquid water, in particular by bubbling, is more effective when the liquid water height is reduced. In the present embodiment, the heater 22 is shown as an example within the inlet duct of the compressor 32 which opens into the first low pressure vessel 10.

In the present embodiment, the line 38 for recovering the liquid water produced by the condenser 34 is connected to the line 18 and the liquid water recovered via the line 38 is discharged into the tanks 12] _ to 12- ^ by means of a pump 92, for example a positive displacement pump. According to another embodiment, the pump 92 may not be present, the circulation of liquid water in the pipes 18 and 38 then resulting only the pressure difference between the speakers 10 and 30.

In the present embodiment, the condenser 34 comprises nozzles 94 for spraying liquid water into the second low pressure chamber 30 in the form of droplets 96, three nozzles 94 being represented by way of example in FIG. Cold droplets 96 promote the condensation of water vapor expelled into the second chamber 30 at low pressure by the compressor 32, by multiplying the steam / liquid interfaces promoting the adsorption of water vapor. The liquid water is collected in a tank 98, formed for example by the bottom of the second chamber 30 at low pressure. The pipe 38 recovers a portion of the liquid water present in the tank 98. The condenser 34 further comprises a hydraulic circuit 100 in which circulates a portion of the liquid water present in the tank 98, intended to supply the nozzles 94 in cooled water. The hydraulic circuit 100 comprises a pump 102 for circulating the liquid water and a heat exchanger 104 located outside the second enclosure 30 at low pressure, for example a heat exchanger cooled by the ambient air , the condenser 34 comprising means, for example the fan 36 described above, for circulating ambient air through the heat exchanger 104. Alternatively, the exchanger 104 can be cooled by another source , for example a stream. The liquid water expelled by the nozzles 94, which has been cooled by the exchanger 104, is for example at room temperature. According to one embodiment, the temperature of the droplets 96 at the outlet of the nozzles 94 is lower than the temperature of the liquid water which supplies the hydraulic circuit 100 with at least 10 ° C.

In the present embodiment, the system 42 for regulating the pressure difference between the second low-pressure enclosure 30 and the first low-pressure enclosure 10 comprises a pipe 106 connected to the second low-pressure enclosure 30 in the the enclosure 30 containing steam of water, the pipe 106 being equipped with a controllable flow control valve 108 and feeds an expansion turbine 110. The outlet of the turbine 110 is connected to a pipe 112 which feeds each tank 12] _ 12 ^. The turbine 110 receives water vapor at the pressure of the second low-pressure chamber 30, which is already cooled by the droplet condenser 34, and provides a two-phase mixture comprising liquid water and steam. water. The rotational speed of the turbine 110 is adjusted so that the discharged water vapor has the desired pressure. According to one embodiment, in the biphasic mixture at the outlet of the turbine 110, the liquid water has been cooled by expansion and the water vapor is substantially at the desired pressure in the first enclosure 10 at low pressure. The water vapor expelled through line 112 into each tank 12 may advantageously act as a stirrer for the liquid water present in tanks 12 to 12 and further promotes the cooling of the liquid water contained in the tanks 12] to 12- ^. The turbine 110 and the valve 108 can be controlled by the processing module 40, not shown in FIG.

In the present embodiment, the cold power extraction device 24 in the tanks 12 to 12 comprises a hydraulic circuit 114 connected to the tanks 12 through which a portion of the water present in the tanks circulates. tanks 12] _ to The hydraulic circuit 114 comprises a pump 116 for circulating the liquid water and a heat exchanger 118 located outside the first enclosure 10 at low pressure, for example a heat exchanger cooperating with a heat exchanger 120 of another hydraulic circuit 122 connected to a device 124 to cool. As shown in FIG. 10, the hydraulic circuit 114 can be connected to the pipe 18 for the delivery of the liquid water flowing in the hydraulic circuit 114 to the tanks 12] at 12 _N. In the present embodiment, the turbocharger 32 comprises two successive stages 130 and 132. The first stage 130 has a fixed compression ratio, for example equal to about 3, and the second stage 132 has a controllable variable compression ratio. The rotational speed of the second turbomachine 132 can be controlled by the processing module 40, not shown in FIG. 10. Preferably, each stage 130, 132 corresponds to a turbocharger. The first stage 130 makes it possible to control the flow rate of water vapor extracted from the first enclosure 10 at low pressure. The second stage 132 makes it possible to fix the pressure of the water vapor discharged into the second chamber 30 at low pressure.

In FIG. 10, there is furthermore a primary vacuum pump 134 connected to the first low-pressure enclosure 10 via a line 136 equipped with a controllable valve 138.

Particular embodiments have been described. Various variations and modifications will be apparent to those skilled in the art. In particular, although in the embodiments described above, the condenser 34 is a capacitor in which the water vapor is cooled and liquefied by the ambient air, other types of condenser 34 may be used, for example a condenser with liquid cooling.

Claims

A refrigeration plant (5; 70) comprising: a first vessel (10) containing water in the liquid state (14) at a temperature less than or equal to the temperature of the triple point of water or greater than temperature of the triple point of the water of less than 10 ° C, and water in the gaseous state (11) at a first pressure equal, within 10%, to the saturation vapor pressure of the water in equilibrium with the pressure of the water in the liquid state (14) in the first chamber;

a second chamber (30) at a second pressure that is strictly greater than the first pressure by at least a factor of two;

a compression device (32) connecting the first chamber to the second chamber adapted to provide a compression ratio greater than two;

a condensation device (34) partially housed in the second chamber and adapted to condense the water in the gaseous state in the second chamber with water in the liquid state; and

a device (24) for extracting cold power in the first enclosure.

2. Refrigeration installation according to claim 1, comprising a device (22) for heating water in the gaseous state in the first chamber (10) intended to feed the compression device (32).

3. Refrigeration plant according to claim 1 or 2, wherein the first chamber (10) further contains water in the solid state (15) at a temperature less than or equal to the temperature of the triple point of the water. .

4. Installation according to any one of claims 1 to 3, wherein the water flows in a closed circuit in one installation.

5. Refrigeration plant according to any one of claims 1 to 4, wherein the condensation device (34) comprises a first heat exchanger outside the second chamber (30) and means (36) for circulating a first heat transfer fluid through the first heat exchanger.

6. Refrigeration plant according to claim 5, wherein the first heat transfer fluid is the ambient air or water of a watercourse, a body of water and / or a body of water. .

7. Refrigeration plant according to any one of claims 1 to 6, wherein the second pressure in the second chamber (30) is less than or equal to 10000 Pa.

8. Refrigeration plant according to any one of claims 1 to 7, wherein the device (24) for extracting cold power comprises a hydraulic circuit in which circulates a portion or all of the water in the present liquid state. in the first chamber (10), the hydraulic circuit comprising a second heat exchanger (68) located outside the first enclosure.

9. Refrigeration installation according to any one of claims 1 to 7, wherein the device (24) of cold power extraction comprises a closed hydraulic circuit in which circulates a second heat transfer fluid, the hydraulic circuit comprising a second heat exchanger (68) located outside the first enclosure and a third heat exchanger (66) disposed in the first enclosure (10).

10. Refrigeration plant according to claim 8 or 9, comprising a third enclosure (80) in which is located the second heat exchanger (68) and containing water in the solid state (84).

11. Refrigeration plant according to any one of claims 1 to 10, wherein the heating device

(22) comprises a source of microwave radiation and / or a source of infrared radiation.

12. Refrigeration plant according to any one of claims 1 to 11, wherein the heating device (22) is adapted to heat at least 2 ° C water in the gaseous state. in the first enclosure (10) for supplying the compression device (32).

13. Refrigeration installation according to any one of claims 1 to 12, wherein the compression device (32) comprises at least one turbine engine type compressor.

14. Refrigeration installation according to any one of claims 1 to 13, wherein the compression device (32) comprises a succession of stages, each stage comprising a rotor and a stator.

15. Refrigerating plant according to any one of claims 1 to 14, wherein the compression device (32) is a Tesla compressor.

The refrigeration plant according to any one of claims 1 to 15, wherein the compression device (32) comprises a first fixed compression ratio compressor stage (130) and a second rate compressor stage (132). controllable compression.

17. Refrigeration plant according to any one of claims 1 to 16, further comprising, in the first chamber, a device (20) for protecting the compression device (32) against the admission of particles in the solid state. and / or liquid.

18. Refrigeration plant according to any one of claims 1 to 17, comprising a conduit (18) for supplying water in the liquid state (14) in the first chamber (10).

19. Installation according to any one of claims 1 to 18, wherein the condensation device (34) comprises at least one nozzle (94) for projecting droplets (96) of water in the liquid state in the second chamber (30).

20. Installation according to any one of claims 1 to 19, further comprising a system (42) for regulating the pressure difference between the second chamber (30) and the first chamber (10).

Apparatus according to claim 20, wherein the control system (42) comprises a turbine (110) detent device configured to release gaseous water from the second chamber (30) and discharge a mixture containing gaseous water and liquid water into the first chamber ( 10).

22. Installation according to claim 21, wherein the first chamber (10) comprises at least one reservoir (12; 121 to 12 _j ^) of water in the liquid state and in which said mixture is discharged into the water. the liquid state contained in said reservoir.

23. An air conditioning system for industrial installations comprising a refrigeration plant according to any one of claims 1 to 22.

24. Artificial snow production system comprising a refrigeration plant (5) according to any one of claims 1 to 22.

25. Process for producing cold comprising the following steps:

bringing water in the liquid state (14) to a first chamber (10) at a temperature less than or equal to the temperature of the triple point of the water or greater than the temperature of the triple point of the water less than from 10 ° C, and form water in the gaseous state at a first pressure equal to 10%, at the saturation vapor pressure of the water in equilibrium with the water pressure in the state liquid in the first chamber;

extract cold power into the first enclosure.

The method of claim 25, further comprising the step of heating the gaseous water in the first chamber to be compressed.