Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B1/00—Compression machines, plants or systems with non-reversible cycle
  • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B49/00—Arrangement or mounting of control or safety devices
  • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
  • F25B49/025—Motor control arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B13/00—Compression machines, plants or systems, with reversible cycle
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/04—Refrigeration circuit bypassing means
  • F25B2400/0401—Refrigeration circuit bypassing means for the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/07—Details of compressors or related parts
  • F25B2400/075—Details of compressors or related parts with parallel compressors
  • F25B2400/0751—Details of compressors or related parts with parallel compressors the compressors having different capacities
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/13—Economisers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2600/00—Control issues
  • F25B2600/02—Compressor control
  • F25B2600/025—Compressor control by controlling speed
  • F25B2600/0253—Compressor control by controlling speed with variable speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/15—Power, e.g. by voltage or current
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2115—Temperatures of a compressor or the drive means therefor
  • F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2115—Temperatures of a compressor or the drive means therefor
  • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2116—Temperatures of a condenser
  • F25B2700/21161—Temperatures of a condenser of the fluid heated by the condenser
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/21—Temperatures
  • F25B2700/2117—Temperatures of an evaporator
  • F25B2700/21171—Temperatures of an evaporator of the fluid cooled by the evaporator
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

• the invention relates to a heat exchange system and to a method of regulating the thermal power developed by such a heat exchange system.
• the invention relates to a heat exchange system adapted to perform heat exchange between outside air located outside a space and an internal medium flowing inside the space, said heat exchange system comprising:
• first and second heat exchangers for exchanging heat respectively with the outside air and the interior medium, said first and second heat exchangers each having an inlet and an outlet and forming one an evaporator and the other an condenser,
• a coolant circuit adapted to circulate a coolant between the evaporator and the condenser, said coolant circuit comprising a compression unit placed between the outlet of the evaporator and the inlet of the condenser, and a unit of expansion located between the condenser outlet and the inlet of the evaporator, - a control unit connected to the coolant circuit.
• the invention applies, in particular, to the regulation of a thermal power developed by the heat exchange system, in particular in an operation as a heat pump associated with a space or a building, to allow to maintain an instruction of temperature inside the space or the building by bringing to this space or this building a thermal power equivalent to the thermal losses (internal and external contributions deducted).
• a vapor compression air / water heat pump recovers heat from outside air at an outside temperature, and then transmits this heat to the space at a temperature of a heating water circuit.
• the compression unit has a constant capacity (constant suction flow)
• the thermal power of the cycle will decrease with the outside temperature (the density of the heat transfer fluid at the suction of the compression unit decreases, therefore, the mass flow rate of the coolant in the cycle decreases, and the thermal power carried by the heat transfer fluid of a cold source to which the evaporator draws heat to a hot well to which the condenser transfers the heat removed decreases).
• the calorific demand of the building and the heat production of the heat pump are therefore in opposition. If the heat pump is dimensioned to meet the needs at a given outdoor temperature, it will be more powerful at higher outdoor temperatures with, for cons, performance losses related to the cycling of the heat pump (on / off) and the surplus heat transported (exchanger losses, pressure losses).
• the known heat exchange systems do not, however, make it possible in a simple manner to precisely regulate the thermal power developed by the heat exchange system.
• the invention improves the situation.
• the invention proposes a heat exchange system adapted to perform heat exchanges between outside air located outside a space and an internal medium circulating inside of space, said heat exchange system comprising:
• first and second heat exchangers for exchanging heat respectively with the outside air and the interior medium, said first and second heat exchangers each having an inlet and an outlet and forming one an evaporator and the other an condenser, a coolant circuit adapted to circulate a coolant between the evaporator and the condenser, said coolant circuit comprising a compression unit placed between the outlet of the evaporator and the inlet of the condenser, and a unit of a detent placed between the outlet of the condenser and the inlet of the evaporator, said compression unit comprising at least first and second compression stages arranged in series, the first compression stage discharging the coolant in the second compression stage,
• the first compression stage comprises a plurality of fixed capacity compressors connected in parallel and has a step variable capacitance, said plurality of fixed capacity compressors having a plurality of different configurations defining the capacitance steps
• the second stage of compression comprises at least one variable capacity compressor and has a continuously variable capacity
• the control unit being adapted to regulate a thermal power developed by the heat exchange system from variations of the capacities of the first and second stages of compression , the control unit being adapted for:
• the heat exchange system according to the invention has a simple structure whose thermal power can be regulated precisely according to the heat demand of the space.
• the capacity of the first compression stage is chosen from a plurality of discrete capacitance values to reach a thermal power close to a target thermal power, and the capacity of the second compression stage is modulated to approach the target thermal power.
• the compression unit may comprise a bypass line connected in parallel with the first compression stage, the control unit being adapted to control:
• the heat exchange system may further comprise a subcooling exchanger located between the first and second heat exchangers, and an injection line connecting the second heat exchanger to a suction inlet.
• the control unit being adapted for, in multi-stage operation, circulating a first portion of the coolant from the outlet of the second heat exchanger forming the condenser to the suction inlet of the second compression stage by the injection pipe, and a second portion of the heat transfer fluid from the outlet of the second heat exchanger forming the condenser to the inlet of the first heat exchanger forming the evaporator .
• the heat exchange system may further comprise an air circuit and a water circuit to which the first and second heat exchangers are respectively associated, and wherein the control unit can be adapted. for measuring a water temperature in the water circuit and for determining a set water temperature in the water circuit, the control unit being adapted for successively and continuously:
• the control unit can then be adapted to measure an air temperature in the air circuit, the control unit being adapted to choose an initial capacity step of the first compression stage at least as a function of the temperature of the air. 'air. Furthermore, the control unit can be adapted to select an initial capacity of the second compression stage at least as a function of the capacity step of the first compression stage. In addition, the control unit is adapted to change the capacity step of the first compression stage if the capacity of the second compression stage is in a determined range.
• the heat exchange system may further comprise an air circuit and a water circuit to which the first and second heat exchangers are respectively associated, and wherein the control unit may be adapted to measure a water temperature in the water circuit and to determine a set water temperature in the water circuit, the control unit being adapted for successively and continuously:
• the control unit can then be adapted to measure an air temperature in the air circuit and to determine a target thermal power, the control unit being adapted to determine the plurality of capacitance couples as a function of the temperature. of air and the target thermal power.
• control unit may be adapted to limit the capacity of the second compression stage between a minimum capacity and a maximum capacity, said minimum and maximum capacities being chosen to maintain the first and second stages of compression in respective operating envelopes and to obtain a coefficient of performance greater than or equal to a determined minimum coefficient of performance.
• control unit can be adapted to vary the minimum and maximum capacities of the second compression stage according to the capacity step of the first compression stage.
• the control unit can be adapted to reduce the capacity of the second compression stage when a quantity representative of an operating state of the second compression stage reaches a critical value, in particular said quantity is chosen from a temperature measured at the output the second compression stage, a pressure measured at the output of the second compression stage, an electric current supplying the second compression stage and a compression ratio supported by the second compression stage.
• the invention proposes a method of regulating a thermal power developed by a heat exchange system, said method implementing a heat exchange system adapted to perform heat exchange between outside air located outside a space and an interior medium flowing inside the space, said heat exchange system comprising:
• first and second heat exchangers for exchanging heat respectively with the outside air and the interior medium, said first and second heat exchangers each having an inlet and an outlet and forming one an evaporator and the other an condenser,
• a coolant circuit adapted to circulate a coolant between the evaporator and the condenser, said coolant circuit comprising a compression unit placed between the outlet of the evaporator and the inlet of the condenser, and a unit of a detent placed between the outlet of the condenser and the inlet of the evaporator, said compression unit comprising at least first and second compression stages arranged in series, the first compression stage discharging the coolant in the second compression stage, the first compression stage comprising a plurality of fixed capacity compressors connected in parallel and having a pitch variable capacitance, said plurality of fixed capacity compressors having a plurality of different configurations defining the capacitance steps, and the second compression stage comprising at least one compressor with variable capacity and prese being a continuously variable capacitor,
• said regulating method providing for regulating the thermal power developed by the heat exchange system from variations in the capacities of the first and second compression stages, said regulation method providing for:
• the regulation method implements a heat exchange system as defined above.
• the compression unit may include a branch line connected in parallel with the first stage of compression.
• the control method can then provide for controlling:
• the heat exchange system may further comprise a subcooling exchanger located between the first and second heat exchangers, and an injection line connecting the first heat exchanger to a suction inlet. the second compression stage through the subcooling exchanger.
• the control method can then provide, in multi-stage operation, to circulate a first portion of the heat transfer fluid from the outlet of the first heat exchanger forming the condenser to the suction inlet of the second compression stage by the control pipe. injection, and a second portion of the heat transfer fluid from the outlet of the first heat exchanger forming the condenser to the inlet of the second heat exchanger forming the evaporator.
• the heat exchange system may further comprise an air circuit and a water circuit to which the first and second heat exchangers are respectively associated, the control method being able to provide:
• the control method can provide:
• the control method may provide for selecting an initial capacity of the second compression stage at least as a function of the capacity step of the first compression stage.
• the control method may provide for changing the capacity step of the first compression stage if the capacity of the second compression stage is in a determined range.
• the heat exchange system may further comprise an air circuit and a water circuit to which the first and second heat exchangers are respectively associated, the control method being able to provide:
• the control method can provide:
• control method may provide for limiting the capacity of the second compression stage between a minimum capacity and a maximum capacity, said minimum and maximum capacities being chosen to maintain the first and second compression stages in respective operating envelopes and to obtain a determined coefficient of performance.
• the control method may provide for varying the minimum and maximum capacities of the second compression stage according to the capacity step of the first compression stage.
• the control method can provide for reducing the capacity of the second compression stage when a quantity representative of an operating state of the second compression stage reaches a critical value, in particular said quantity is chosen from a temperature measured at the output of the second compression stage, a pressure measured at the output of the second compression stage, an electric current supplying the second compression stage and a compression ratio supported by the second compression stage.
• FIG. 1 is a schematic representation of a heat exchange system according to one embodiment of the invention, the heat exchange system comprising a two-stage compression unit, the compression unit comprising a first stage a stepwise variable compression device and a second continuously variable series compression stage, the heat exchange system operating in an air conditioner mode,
• FIG. 2 is a schematic representation of the heat exchange system of FIG. 1 operating in a heat pump mode
• FIG. 3 is a diagrammatic representation of four configurations of the first compression stage of the heat exchange system of FIG. 2, the configurations making it possible to obtain different thermal powers developed by the heat exchange system
• FIG. 4 is a graph schematically illustrating the evolution of the thermal power developed by each of the configurations of FIG. 3 as a function of an outside temperature located outside a space to be heated
• FIG. 5 is a diagram illustrating the steps of a first embodiment of a method for regulating the thermal power developed by the heat exchange system of FIG. 2, the regulation method providing for regulating the thermal power. by choosing a capacity step of the first compression stage and then varying the capacity of the second compression stage,
• FIG. 6 illustrates a step of selecting the initial configuration of the first compression stage in the control method of FIG. 5, the selection being made as a function of the outside temperature
• FIG. 7 illustrates a variant of the step of selecting the initial configuration of the first compression stage in the control method of FIG. 5, the selection being made from abacuses giving the initial configuration as a function of the temperature. outside, a target water temperature and a target thermal power,
• FIG. 8 is a diagram illustrating the steps of a second embodiment of the method of regulating the thermal power developed by the heat exchange system of FIG. 2, the regulation method providing for regulating the thermal power by choosing one of a plurality of capacitance couples each comprising one of the capacitance steps of the first compression stage and one of the capacitances of the second compression stage,
• FIG. 9 illustrates a torque selection step comprising the configuration of the first compression stage and the capacity of the second compression stage in the control method of FIG. 8, the selection being made from abacuses giving the torque in FIG. depending on the outside temperature, a set water temperature and a power indicator.
• FIGS. 1 and 2 show a heat exchange system 1 respectively for cooling and heating an internal medium, for example water, circulating in a space 2, such as a part of a dwelling, a technical room or other.
• a space 2 such as a part of a dwelling, a technical room or other.
• the internal environment could be other than water, including air.
• the heat exchange system 1 allows either to heat the water by drawing heat from outside air located outside the space 2 (cold source) and transferring to the water (hot source / hot well) the heat taken (Figure 2), either to cool the water by taking heat (cold source) and transferring to the outside air (hot source / hot well) the heat taken ( figure 1 ).
• the heat exchange system 1 comprises:
• first heat exchanger 5 selectively forming an evaporator or a condenser, intended to perform heat exchanges with the outside air, the first heat exchanger having a first end 6 and a second end which form one input E and the other an output S,
• a second heat exchanger 15 selectively forming an evaporator or a condenser, intended to perform heat exchanges with water, the second heat exchanger having a first end and a second end forming an inlet; E and the other an output S,
• a heat transfer fluid circuit connected to the first and second heat exchangers and adapted to circulate a heat transfer fluid, such as a refrigerant, between the first heat exchanger and the second heat exchanger.
• the heat transfer fluid circuit comprises a multi-stage compression unit 20 and an expansion unit 10.
• the compression unit 20 is bi-staged and comprises a first compression stage 21 and a second compression stage 22 arranged in series.
• the compression unit 20 could comprise more than two compression stages arranged in series.
• the first compression stage or low pressure (LP) compression stage 21 has a pitch variable capacitance, i.e., it has a plurality of discrete capacitance values each defining a capacitance step.
• the low pressure compression stage 21 comprises only several compressors with fixed capacity connected in parallel, and does not have a variable capacity compressor.
• the low pressure compression stage 21 comprises two first compressors or low pressure compressors (LP) 23a, 23b connected in parallel.
• the low-pressure compressors 23a, 23b respectively have different displacements.
• the low-pressure compressor 23b has a higher capacity than that of the low pressure compressor 23a.
• the low pressure compression stage 21 could comprise one or more two low pressure compressors 23 in parallel.
• the second compression stage or high pressure (HP) compression stage 22 has a continuously variable capacitance, i.e. it has a plurality of capacitance values in a determined range.
• the high pressure compression stage 22 comprises one or more variable speed compressors.
• the high pressure compression stage 22 is devoid of fixed capacity compressor and comprises a single second compressor or high pressure compressor (HP) 24.
• the high pressure compression stage 22 could comprise a plurality of high-pressure compressors 24 in parallel, at least one of which is of continuously variable capacity.
• Each of the low pressure compressors 23a, 23b and high pressure 24 has a suction inlet 25 and a discharge outlet 26.
• the suction inlets 25 of the low pressure compressors 23a, 23b are connected to a same suction line 27 and the discharge outlets 26 of the low pressure compressors 23a, 23b are connected to the same discharge line 28.
• the low pressure compressors 23a, 23b and high pressure 24 are arranged in series, that is to say that is, the delivery line 28 of the low-pressure compressors 23a, 23b is connected to the suction inlet 25 of the high-pressure compressor 24.
• suction line 27 low pressure compressors 23a, 23b are connected to the output S of the first and second heat exchangers 15 which form the evaporator, and the discharge outlet 26 of the high pressure compressor 24 e It is connected to the inlet E of the first 5 and second 15 heat exchangers which forms the condenser.
• the compression unit 20 comprises a bypass line January 1 provided with a valve 12 connected in parallel with the compression stage low pressure 21, with an upstream end connected upstream of the suction line 27 and a downstream end connected downstream of the discharge line 28 of the low pressure compressors 23a, 23b.
• the bypass line 1 1 bypasses the low pressure compression stage 21 to use only the high pressure compression stage 22 in the single-stage operation.
• a bypass line 3 provided with a valve 4 may also be provided in parallel with the high pressure compression stage 22, with an upstream end connected upstream of the suction inlet 25 and a connected downstream end. downstream of the discharge outlet 26 of the high-pressure compressor 24.
• This bypass line 3 has a role of protection against possible high pressures in the event of failure of the high-pressure compressor 24 while the low-pressure compressors 23a, 23b are in walk.
• the heat exchange system used in heat pump mode described below and according to the two-stage operation, operates according to an injection cycle with a subcooling exchanger 45 or economizer.
• the subcooling exchanger 45 is connected to the first end 6 of the first heat exchanger 5 and to the second end 17 of the second heat exchanger 15.
• the heat exchange system 1 further comprises a heat pipe.
• injection 46 connecting the second end 17 of the second heat exchanger 15 to the suction inlet 25 of the high pressure compressor 24 through the subcooling exchanger 45.
• a pressure regulator 47 is placed in the injection line 46, between the second heat exchanger 15 and the subcooling exchanger.
• a liquid receiver 48 may be provided. It is thus possible to cool the heat transfer fluid between the low pressure compression stage 21 and the high pressure compression stage 22 to limit the temperature at the discharge outlet 26 of the high pressure compression stage 22 and thereby achieve a higher condensing pressure.
• the cooling is carried out here by taking condensed heat transfer fluid at the outlet of the condenser and re-injecting it between the delivery line 28 of the low pressure compression stage 21 and the suction inlet 25 of the compression stage. 22.
• the invention is however not limited to a heat exchange system implementing an injection cycle with a subcooling exchanger and applies to a heat exchange system implementing, for example a total injection cycle, a partial injection cycle or a cascade cycle, the heat exchange system being adapted accordingly.
• the heat transfer fluid circuit also comprises a distribution circuit 40 for circulating the coolant from the compression unit 20 to the first heat exchanger 5 or from the compression unit 20 to the second heat exchanger 15 in order to ensure the reversibility or invertibility of the heat exchange system 1.
• the distribution circuit 40 comprises a compression loop 41 in which the low-pressure compressors 23a, 23b and high-pressure 24 are placed, and a four-way valve 42 connecting the compression loop 41 to the first 5 and second 15 heat exchangers. heat.
• the four-way valve 42 is adapted to circulate the heat transfer fluid from one of the first 5 and second 15 heat exchangers and entering the compression loop 41 to the suction line 27 of the low-pressure compressors 23a, 23b, and for distributing the heat transfer fluid from the discharge outlet 26 of the high pressure compressor 24 to the other heat exchanger 5, 15.
• the expansion unit 10 comprises an expansion valve connecting via one or more pipes the output of that of the first and second heat exchangers which forms the condenser and the inlet of the first and second heat exchangers which forms the evaporator.
• the heat exchange system 1 also comprises an air circuit 35 associated with the first heat exchanger 5 to achieve a heat exchange between the coolant and the outside air, and a water circuit 36 associated with the second heat exchanger 15 to achieve a heat exchange between the coolant and the water circulating inside the space 2.
• the air circuit 35 may comprise pipes, not shown, connected to an air intake and an air outlet, and a fan 39 adapted to circulate the air between the air inlet and the air outlet through the first heat exchanger 5.
• the water circuit 36 for example d a sanitary heating or floor heating installation may include pipes connected to a pumping system ensuring the circulation of water in the pipes.
• the heat exchange system 1 can operate in an air conditioner mode ( Figure 1) or in a heat pump mode ( Figure 2).
• a control of the heat exchange system 1 between the different modes is provided by a control unit connected to the coolant circuit.
• the control unit comprises for example an electronic microprocessor to which a temperature sensor adapted to measure an outside temperature (Text) of the outside air is connected.
• Other sensors or instruments Measurement of the control unit can be connected to the electronic microprocessor.
• the control unit may comprise a temperature probe adapted to measure an internal temperature (Tint) of the indoor air located inside the space 2, a temperature probe adapted to measure the temperature of water (Tw) in the water circuit 36.
• the control unit may also comprise a memory in which different data, and in particular a threshold temperature for the outside temperature and a set water temperature (Tw_c) for the circuit water 36 or, as will appear in the following description, abacuses or water laws, are stored.
• a threshold temperature for the outside temperature and a set water temperature (Tw_c) for the circuit water 36 or, as will appear in the following description, abacuses or water laws, are stored.
• the control of the heat exchange system 1 according to the air conditioner mode and the heat pump mode can be achieved according to the need for cooling or heating of the indoor environment.
• the need for cooling or heating can be determined in any suitable manner.
• an operator can choose the mode by acting directly on an input interface of the control unit.
• the control unit may include a thermostat measuring a temperature of the indoor environment and determining the mode of the heat exchange system 1 from a set temperature for the indoor environment.
• the control unit can determine the mode of the heat exchange system 1 from the outside temperature, in particular by means of a water law stored in the memory of the control unit. .
• the heat exchange system 1 when there is a need for cooling of the internal environment, the heat exchange system 1 is in air conditioner mode, shown in FIG. 1.
• the heat transfer fluid then circulates in a closed loop:
• the second heat exchanger 15 From the first end 16, forming the output S, the second heat exchanger 15 to the compression unit 20.
• the second heat exchanger 15 forms the evaporator removing heat to the interior and the first heat exchanger 5 forms the condenser transferring the heat to the outside air, so as to cool the internal environment.
• the heat exchange system 1 is in heat pump mode, shown in Figure 2.
• the heat transfer fluid then circulates in a closed loop:
• the first heat exchanger 5 forms the evaporator which draws heat from the outside air and the second heat exchanger 15 forms the heat transfer condenser, thereby heating the interior medium.
• the heat exchange system described above makes it possible in particular to ensure operation in heat pump mode in which a thermal power level can be adjusted by acting on the capacity step of the low pressure compression stage 21, the capacity of the continuously variable high pressure compression stage 22 being modulated to regulate the thermal power of the heat pump (around a value set by the capacity step of the low pressure compression stage 21).
• the compression unit 20 can deliver a higher or lower condensation pressure so as to regulate the power thermal system developed by the heat exchange system.
• the higher-capacity 23b low-pressure compressor operates in series with the high-pressure compressor 24 enabling the heat exchange system to develop a thermal power in a third range, greater than the first and second ranges, depending in particular on the speed of the high-pressure compressor 24 and an outside temperature of the outside air.
• the two low-pressure compressors 23a, 23b operate in series with the high-pressure compressor 24 enabling the heat exchange system to develop a thermal power in a fourth range, greater than the first, second and third ranges, depending in particular on the speed of the high pressure compressor 24 and an outside temperature of the outside air.
• a relative dimensioning of the low-pressure compressors 23a, 23b and high-pressure compressors 24 for the third two-stage operation offering an optimized coefficient of performance is:
• variable speed compressor 24 having a capacity ranging from X to 100%, with X less than 50%
• the control unit acts on the heat transfer fluid circuit so that a first portion of the heat transfer fluid circulates from the second end 17 (outlet) of the second heat exchanger 15 (condenser) to the suction inlet 25 of the high pressure compressor 24 through the injection pipe 46, and a second portion of the heat transfer fluid from the second end 17 (outlet ) of the second heat exchanger 15 (condenser) to the first end 6 (inlet) of the first heat exchanger 5 (evaporator).
• the heat exchange system then makes it possible to implement a control method that allows, for each capacity step of the first compression stage 21 defining a main power level (determined by the configuration of low pressure compressors 23a , 23b in operation), to benefit from a range of regulation of the thermal power of the heat pump, by acting on the speed of the high-pressure compressor 24. It is thus possible to regulate more finely the thermal power of the heat pump and reduce losses due to configuration changes and overpowering operation. On the other hand, the regulation process does not aim at maximizing the instantaneous coefficient of performance (COP) of the heat exchange system 1.
• COP instantaneous coefficient of performance
• a main control loop that manages the choice of low-pressure compressors 23a, 23b in operation, that is to say the choice of the configuration of the low-pressure compression stage 21, or the choice of the capacity step the low pressure compression stage 21, and
• step S1 A secondary control loop that regulates the speed of the high pressure compressor 24 to modulate the heat output level of the heat pump around the main level.
• the initial configuration of the low pressure compression stage 21 is selected (step S1).
• each configuration Config.1, Config.2, Config.3 and Config. 4 may then correspond to a defined external temperature range Text, for example respectively between 5 ° C and 15 ° C, between 0 ° C and 5 ° C, between -5 ° C and 0 ° C and -10 ° C and -5 ° C.
• the selection of the starting configuration is based on charts, shown in FIG. 7, or interpolation functions stored in the control unit and giving the starting configuration as a function of the temperature.
• Tw_c f (Text)
• the target thermal power to be delivered obtained in particular by a power law, depending on the outside temperature Text.
• the first available configuration of higher capacity can be selected.
• the configuration which presents the best instantaneous energetic efficiency at the considered point can be selected.
• the start-up configuration can possibly be modulated by the measurement / setpoint error on the water temperature Tw at startup.
• the initial speed of the high pressure compressor 24 is then selected (step S2).
• the selection of the initial speed is based on the configuration of the low-pressure compression stage 21 only (typically median value of the range of variation).
• the selection of the initial speed is made from charts or interpolation functions stored in the control unit and giving the initial speed of the high-pressure compressor 24 as a function of the configuration of the low-pressure compressors. 23a, 23b, the estimated thermal power and the external temperature Text (and possibly the set water temperature Tw_c).
• the selection of the initial speed is done in a mixed way, as a function of the configuration of the low-pressure compressors 23a, 23b for the two-stage operations, and as a function of the estimated thermal power and the outside temperature. (and possibly the set water temperature Tw_c) for single-stage operation.
• the compressors of the low pressure compression stage 21 are then actuated according to the initial configuration selected (step S3).
• step S4 It then enters the secondary control loop in which the speed of the high pressure compressor 24 is managed by a regulator of the control unit intended to reduce the difference between the measured water temperature Tw_mes fatee and the set water temperature Tw_c (step S4) .
• This deviation is determined by the absolute value of the difference between the measured water temperature Tw_mes fatee and the temperature setpoint water Tw_c (abs (Tw_measured-Tw_c)).
• the measured water temperature Tw_measured may be the water flow temperature (at the heat pump outlet), the water return temperature (at the heat pump inlet) or a combination of the two.
• the controller used can be a controller of PID, PI, fuzzy logic, state space, etc.
• the regulator has for input the error measurement / instruction, with generally the evolution of this error, possibly taking into account the external temperature Text and its evolution.
• the speed of the high pressure compressor 24 is preferably limited between a maximum speed or capacity and a minimum speed or capacity to guarantee the operation of the compressors in their respective operating envelopes and an instantaneous coefficient of performance (COP) greater than or equal to a minimum coefficient of performance determined and deemed acceptable.
• the terminals can be:
• the operating limits to measured operating conditions, such as the suction and discharge pressures of the low pressure compressors 23a, 23b and / or high pressure 24, the discharge temperatures of the low pressure compressors 23a , 23b and / or high pressure 24, intensity of the current in the compressors and the compression ratios supported by the low pressure and / or high pressure compressors.
• An additional level of regulation may be provided to reduce the speed of the high pressure compressor 24 when one of the above operating conditions reaches a critical value, and in particular when:
• the delivery temperature of the high-pressure compressor 24 approaches a maximum value (by acting on the setpoint of the secondary regulation loop),
• the current in the high-pressure compressor 24 approaches a maximum value (by acting on the setpoint of the secondary loop).
• the condensing pressure at the output of the high pressure compressor 24 approaches a maximum value (by acting on the setpoint of the main loop).
• the main control loop then acts on the main heat output level of the heat pump which is regulated so that the water temperature Tw in the water circuit 36 approaches the set water temperature Tw_c.
• the choice of the configuration of the low pressure compression stage 21 is managed by a simple loop which increments or decrements the configuration when the water temperature Tw exits a range Tw_c +/- ATw (steps S5 and S6, S7 and S8).
• the main control loop is preferably provided by a discrete output type PID controller, possibly with hysteresis and / or a minimum duration between two configuration changes.
• This controller may optionally include an operating point, that is to say a calculated estimated configuration (charts) as a function of the outside temperature, and, possibly, depending on the water loop setpoint temperature (law of water) and the thermal power to be delivered (power law).
• the PID controller modulates the estimated configuration according to the measurement / setpoint error on the water temperature Tw.
• the controller of the main control loop can manage the succession of configurations of the low pressure compression stage 21 to maintain the water temperature Tw in a range defined around the setpoint Tw_c, with hysteresis and / or a minimum duration between two configuration changes.
• step S5 when the speed of the high-pressure compressor 24 reaches a maximum speed Vmax and the measured water temperature Tw_mes fatee remains lower than the set water temperature Tw_c, to a certain extent ATw predefined, the next configuration of higher available capacity is selected (steps S5 and S6).
• step S7 and S8 the next configuration of lower capacity available is selected (steps S7 and S8).
• some configurations may not be available. For example, single-stage operation is not available when the overall compression ratio is too large to be supported by the single high pressure compressor 24.
• control method can be carried out continuously, continuously measuring the control variables such as the outdoor and water temperatures and successively performing the steps described above.
• This method is based on the knowledge of the complete functioning mapping of the heat pump, in the form of charts, shown in FIG. 9, or of interpolation functions stored in the control unit.
• the power demanded by the regulator from the heat pump is given by a capacity indicator I which varies continuously in the same direction as the thermal power supplied by the heat pump.
• This indicator I is translated, thanks to the complete mapping, into a pair comprising a capacity step corresponding to a configuration of the low-pressure compression stage 21, and a speed of the high-pressure compressor 24, the torque thus determined being applied to the heat pump.
• the regulator controls this indicator I to act on the thermal power of the heat pump.
• the controller used can be PID, PI, fuzzy logic, state space, etc.
• the controller controls the capacity indicator I to reduce the difference between the measured water temperature Tw_measured and the set water temperature Tw_c (abs (tw_measured-Tw_c)) (step S1 ').
• the regulator has as input the difference between the measured water temperature Tw_measured and the set water temperature Tw_c, with generally the evolution of this difference, possibly taking into account the external temperature Text and its evolution.
• the capacitance indicator I is then translated into a configuration choice of the low pressure compression stage 21 and a speed of the high pressure compressor 24, taking into account the outside temperature Text and the water temperature Tw (step S2 '). It is this step which is based on the detailed knowledge of the heat pump, whose operation mapping is represented by interpolation functions or charts ( Figure 9).
• the control unit determines the torques comprising the capacity step of the low-pressure compression stage 21 and the speed of the high-pressure compressor 24 available, that is, that is, compatible with the operating envelopes of the compressors and with a sufficient instantaneous coefficient of performance. Of the couples available, a couple is selected. If the configuration of the low pressure compression stage 21 in progress is available, it is selected. If the current configuration is no longer available, the next available configuration is selected. Optionally, an additional condition may impose a minimum time between two configuration changes.
• the low pressure compressors 23a, 23b are turned on or off according to the selected configuration (steps S3 'and S4'). On the other hand, if the selected configuration is not different from the current configuration, only the speed of the high pressure compressor 24 is changed to reach the selected speed.
• the step of selecting the torque comprising the capacity step of the low pressure compression stage 21 and the speed of the high pressure compressor 24 can be treated in several ways, in particular with or without hysteresis, with or without additional conditions over the duration minimum between two configuration changes, etc.
• the control method can be carried out continuously, continuously measuring the control variables such as the outdoor and water temperatures and successively performing the steps described above.

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• 2011
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