METHOD OF A THERMODYNAMIC SYSTEM

Description

[0001] The present invention relates to a method for a thermodynamic system for heating and air conditioning a building, and for producing domestic hot water.

[0002] In a building, the most energy-intensive systems are heating and cooling, as well as domestic hot water production (DHW). To reduce energy consumption and pollutant emissions, thermodynamic systems, known as heat pumps, are used. These systems recover heat energy from one source and redistribute it to another through the circulation of a refrigerant, as illustrated in document EP0151493.

[0003] The refrigerant circuit includes a compressor compressing the gaseous fluid, then a condenser forming a heat exchanger allowing an exothermic phase change to pass into the liquid phase, then an expansion valve, and finally an evaporator forming a heat exchanger allowing an endothermic phase change to pass into the gaseous phase.

[0004] It is known to create a dual-service system using water as a heat transfer fluid for heating, and possibly for cooling. In this case, there is a heat transfer fluid circuit including an electric circulator, passing through the condenser to recover the released heat, and then distributing it via a three-way valve to a heat exchanger for heating the building, or for heating a domestic hot water tank.

[0005] This dual-service system requires a heating water loop, which adds constraints and costs, and results in heat and electrical losses due to the use of the circulator. Furthermore, air conditioning is limited, with high inertia in switching between heating and cooling functions, due to the volume of heat transfer fluid.

[0006] Another known system directly uses the refrigerant which passes successively to the building's heating exchanger and then to the hot water tank's heating exchanger, forming condensers arranged in series that recover the heat from this fluid.

[0007] However, this system does not offer air conditioning capabilities and is very inflexible due to the two heat exchangers in series. In particular, excessive use of the building's heating system would leave too little energy in the fluid entering the hot water tank, potentially cooling it.

[0008] In addition to this system, it is known to add two valves to the refrigerant circuit, arranged in parallel downstream of the compressor. One valve directs the refrigerant to the hot water tank, which acts as a first condenser, and alternatively, the other valve directs the refrigerant to the building's heating exchanger, which acts as a second condenser. The return lines from the hot water tank and the heating exchanger are combined and fed upstream of the expansion valve.

[0009] Domestic hot water or building heating can be produced alternately. However, when used for cooling for air conditioning, the hot water tank's heat exchanger cannot be isolated or drained, making building air conditioning impossible.

[0010] In addition to this system, it is known to add a heat transfer fluid circuit with a circulator, passing through the hot water tank to heat it. However, this heat transfer fluid circuit with its circulator adds complexity and increases thermal and electrical energy losses.

[0011] The present invention aims in particular to avoid these drawbacks of the prior art.

[0012] The invention relates to a method for a system as described in claim 1. Preferred modes of the invention are described in the dependent claims.

[0013] The invention will be better understood and other features and advantages will become more apparent upon reading the following description, given by way of example, with reference to the accompanying drawings in which: there figure 1 is a diagram of an unclaimed thermodynamic system intended to illustrate the invention, arranged for operation in building heating; the figure 2 is a diagram of this thermodynamic system arranged for operation in heating the hot water tank; the figure 3 is a diagram of this thermodynamic system designed for air conditioning the building; the figures 4a, 4b et 4c They demonstrate the operation of the two three-way valves in this system's circuit, corresponding respectively to building heating, hot water tank heating, and building air conditioning. figure 5 presents three successive stages of draining an internal heat exchanger by natural transfer, with the upper part showing a passage from the hot water heat exchanger to the building heat exchanger, and the lower part conversely from the building heat exchanger to the hot water heat exchanger; and the figure 6 presents three successive stages of emptying an internal exchanger by forced pumping, showing in the upper part a passage from the hot water exchanger to the building exchanger, and in the lower part the reverse from the building exchanger to the hot water exchanger.

[0014] There figure 1 presents a refrigeration fluid circuit comprising a first part 2 including a heat exchanger for exchange with an external environment of the building, such as air or water, or with any other sources such as waste heat, hereafter referred to as the exchanger with an external environment 12. The first part 2 is connected by a first gas line pipe 6 and a second liquid line pipe 8 to a second internal part of a building 4.

[0015] The first part 2 comprises successively, starting from the second pipe 8, a pressure regulator 10 capable of working in both directions of circulation, the exchanger with an external environment 12, and a compressor device 14 capable of working in both directions of circulation.

[0016] The compressor device 14 includes a piloted four-way valve 18 inserted in the first pipeline 6, comprising two ways connected to the two interrupted sides of this first pipeline, and two other ways connected to a compressor 16 working in a single direction.

[0017] One position of the four-way valve 18 connects the inlet of the compressor 16 to the exchanger with an external environment 12 and the outlet to the building 4, to circulate the fluid from this exchanger to the building, conversely the other position of this valve connects the inlet of the compressor to the building and the outlet of the exchanger with an external environment to circulate the fluid in the other direction.

[0018] In the second part 4 the first pipe 6 arrives at a first pilot-operated three-way valve 20, to connect this pipe alternately or simultaneously to one end of an internal heat exchanger for heating or air conditioning of the building 22, and to an internal heat exchanger of a hot water tank 24. The second pipe 8 arrives at a second pilot-operated three-way valve 26, to connect this pipe alternately to the other end of the heating and air conditioning exchanger 22, or of the tank exchanger 24, or to close these two ends.

[0019] In this way, apart from the case of forced pumping of the fluid from a first exchanger to the second exchanger, by simultaneously controlling the two three-way valves 20, 26 which are motorized, the two pipes 6, 8 are connected only on the heating and air conditioning exchanger 22 or on the tank exchanger 24, to make one or the other work alternately, with a refrigerant that can circulate in both directions.

[0020] THE figures 1 And 4a present a building heating operation, the four-way valve 18 being arranged so that the compressor 16 takes the fluid in gaseous phase from the exchanger with an external environment 12, and sends it under pressure into the first pipe 6.

[0021] The two three-way valves 20 and 26 are arranged so that the gaseous fluid then passes only through the heating and cooling heat exchanger 22, where it condenses, releasing heat into the building. The liquid fluid then returns via the second pipe 8 to the expansion valve 10, which reduces its pressure to allow evaporation in the heat exchanger with an external environment 12.

[0022] THE figures 2 And 4b exhibit a similar operation in domestic hot water heating, the two three-way valves 20, 26 being arranged so that the fluid coming from the first pipe 6 passes only through the heat exchanger of the tank 24.

[0023] For these two previous operations, economical and simple heating of the building or hot water is obtained by taking calories from the evaporator formed by the exchanger with an external environment 12, which are redistributed directly by the refrigerant with good efficiency, towards the building or the hot water tank.

[0024] THE figures 3 et 4c exhibit a cooling operation of building 4. The three-way valves 20, 26 are arranged to connect the two pipes 6, 8 only to the heating and air conditioning exchanger 22. The four-way valve 18 is arranged so that the compressor 16 takes the fluid from the first gas line pipe 6 and by extension from the heating and air conditioning exchanger 22, and pumps it to the exchanger with an outside environment 12.

[0025] For this circuit, with also good efficiency, we obtain a condensation of the fluid in vapor phase under pressure in the exchanger with an external environment 12, which evacuates its heat, and after the expansion valve 10 an evaporation of the fluid in liquid phase at low pressure in the heating and air conditioning exchanger 22 which absorbs heat by cooling this building.

[0026] These different operating modes require complete isolation of the internal heat exchanger 22 or 24 when it is not in use, with the two motorized three-way valves 20 and 26 completely closing this heat exchanger. They also require, in the event of a changeover, the transfer of sufficient fluid into the internal heat exchanger 22 or 24, which is becoming active, by draining the refrigerant from the heat exchanger that is becoming inactive.

[0027] There figure 5 presents a first method of drainage by natural transfer. The upper part shows a use which transfers the fluid from the hot water tank exchanger 24 to the heating and air conditioning exchanger 22.

[0028] The first diagram of the upper part shows an initial operating position with the tank exchanger 24, the two three-way valves 20, 26 are open towards this exchanger and closed towards the heating and air conditioning exchanger 22. The compressor 16 is activated if it is initially deactivated, to increase the condensation temperature in the tank exchanger 24.

[0029] This heating, monitored by means of a temperature probe or a pressure sensor, or any other means allowing control of the pressure, is stopped when the desired condensation temperature is considered sufficient to create a positive pressure difference between the exchanger of the tank 24 and the exchanger with an external environment 12.

[0030] The second diagram in the upper section shows a subsequent step where the compressor is stopped.

[0031] The fluid evaporated in the heat exchanger of the tank 24 moves rapidly towards the heat exchanger with an external environment 12 at a cooler temperature, where it condenses. Additional energy from an independent heating system 42, particularly an electric one, can also be used to supplement the heat transfer.

[0032] Once the transfer is complete after a few minutes, we proceed to the next step shown in the third diagram of the upper part, where we switch the two three-way valves 20, 26 to close the tank exchanger 24 and open the heating and air conditioning exchanger 22. We can then proceed with heating or air conditioning the building, by circulating the fluid which is initially entirely in the exchanger with an outside environment 12.

[0033] The lower part shows a transferred use of the heating and air conditioning exchanger 22 to the hot water tank exchanger 24, which is done in a similar way to that shown above by reversing the roles of these two exchangers.

[0034] The first diagram of the lower part shows an initial operating position with the heating and air conditioning exchanger 22, the two three-way valves 20, 26 are open towards this exchanger and closed towards the tank exchanger 24. The compressor 16 is activated if it is initially deactivated, to increase the condensation temperature in the heating and air conditioning exchanger 22.

[0035] This heating, monitored by means of a temperature probe or a pressure sensor, or any other means allowing control of the pressure, is stopped when the desired condensation temperature is considered sufficient to create a positive pressure difference between the heating and air conditioning exchanger 22 and the exchanger with an external environment 12.

[0036] The second diagram in the lower section shows a subsequent stage where the compressor 16 is stopped. The fluid, evaporated in the heating and cooling heat exchanger 22 by the heat input, moves rapidly towards the heat exchanger with an external environment 12 at a cooler temperature, where it condenses. Additional electrical energy for heating can also be used to further facilitate the transfer.

[0037] Once the transfer is complete, after a few minutes we move on to the next step shown in the third diagram of the lower part, where we switch the two three-way valves 20, 26 to close the heating and air conditioning exchanger 22 and open the tank exchanger 24.

[0038] There figure 6 presents a second method of emptying by forced pumping, used in cases where the natural transfer method is not sufficient to ensure complete transfer.

[0039] The upper part shows a transferred use from the hot water tank exchanger 24 to the heating and air conditioning exchanger 22, and the lower part a transferred use in the other direction.

[0040] The first diagram of the upper section shows an initial operating position with the tank heat exchanger 24 open, the two three-way valves 20 and 26 open towards this heat exchanger, and closed towards the heating and air conditioning heat exchanger 22. The first diagram of the lower section shows a reversed initial position, with the heating and air conditioning heat exchanger 22 open and the tank heat exchanger 24 closed. The compressor 16 is stopped, or remains running if the air conditioning is already active.

[0041] The second common diagram for the upper and lower parts shows a complete closure of the two ways of the second three-way valve 26 directed towards the internal exchangers 22, 24, in order to isolate them from each other, and a complete opening of the first three-way valve 20 towards the two internal exchangers 22, 24. After the positioning of the four-way valve 18, a draw is then made by the compressor 16 working in suction from these internal exchangers 22, 24. The low-pressure fluid vaporizes, to be discharged towards the exchanger with an external medium 12 where it condenses in order to be stored.

[0042] A pressure sensor 40 or a temperature probe, or any other means of controlling pressure, disposed between the two three-way valves 20, 26, for example between the tank exchanger 24 and the second three-way valve 26, makes it possible to measure the drop in pressure in the circuit of the two internal exchangers 22, 24, and to check for a sufficiently low pressure indicating sufficient evaporation, that all the fluid has passed through the exchanger with an external medium 12.

[0043] The third diagram of each upper or lower part shows a final position, where the two three-way valves 20, 26 have been operated in order to respectively activate the heating and air conditioning exchanger 22 or the tank exchanger 24 by isolating the other.

[0044] The invention makes it possible to achieve directly with a refrigerant fluid, without going through a heat transfer fluid, and without a circulator of the latter fluid which would consume electricity, all possible combinations of heating or cooling of the building, and heating of domestic hot water.

Claims

1. A method for a thermodynamic system for heating and air-conditioning of a building, and for domestic hot water production, comprising: - a refrigerant circuit, - a compressor device (14) including a controlled four-way valve (18) inserted in a line (6) of said circuit, comprising two ports connected to both sides of said line (6), and two other ports connected to a compressor (16) operating in a single direction, - an expansion valve (10), - an outdoor heat exchanger (12), - a heating and air-conditioning heat exchanger (22) of the building, and - a hot-water tank heat exchanger (24), the system including, in a loop, successively the expansion valve (10) operable in both flow directions, the outdoor heat exchanger (12), the compressor device (14) operable in both flow directions, and a group of heat exchangers comprising the heating and air-conditioning heat exchanger (22) and the hot-water tank heat exchanger (24) disposed in parallel, characterized in that this group includes a first three-way valve at the inlet (20) and a second three-way valve at the outlet (26), able to alternately place in the circuit the heating and air-conditioning heat exchanger (22) or the hot-water tank heat exchanger (24), said service change method, by natural transfer of the refrigerant from the hot-water tank heat exchanger (24) to the heating and air-conditioning heat exchanger (22), being further configured such that, starting from an initial operating position with the tank heat exchanger (24), both three-way valves (20, 26) are open toward this heat exchanger and closed toward the heating and air-conditioning heat exchanger (22), and the compressor (16) is operating so as to increase the condensation temperature in the tank heat exchanger (24), the heating being monitored thanks to a temperature probe or a pressure sensor, or any other means for controlling pressure, and the heating being stopped when the desired condensation temperature is deemed sufficient to create a positive pressure difference between the tank heat exchanger (24) and the outdoor heat exchanger (12), such that the vaporized refrigerant in the tank heat exchanger (24) quickly moves toward the outdoor heat exchanger (12), which has a lower temperature, where it condenses, then, in a second step, the two three-way valves (20, 26) are switched to close the tank heat exchanger (24) and open the heating and air-conditioning heat exchanger (22).

2. The method according to claim 1, characterized in that each three-way valve (20, 26) is capable of independently closing each port directed toward the heating and air-conditioning heat exchanger (22) of the building or the hot-water tank heat exchanger (24).

3. The method according to any one of the preceding claims, characterized in that the heating and air-conditioning heat exchanger (22) or the tank heat exchanger (24) includes an auxiliary heating means (42).

4. The method according to any one of the preceding claims, characterized in that the heating and air-conditioning heat exchanger (22) or the tank heat exchanger (24) includes a means for controlling pressure, such as a pressure sensor or a temperature sensor (40).