EP3225922A1 - Cooling, air-conditioning or heating system - Google Patents

Abstract

The invention relates to a system for cooling, air conditioning or heating a building (1) comprising a circuit for modifying the temperature of said building (2) and a hot water heating circuit (3) equipped with a hot water tank (4), said system being based on the principle of the heat pump using air as an external source and having an external heat exchange unit (6) with an evaporator and an indoor unit having a condenser (8) for heating a secondary fluid circulating alternately in the temperature modification circuit (2) and the hot water heating circuit (3) where it provides heating of a tertiary fluid (13); ) feeding the balloon (4) through an exchanger (12) thermally connecting the secondary and tertiary fluids. The main characteristic of a system according to the invention is that it comprises an automatic control device allowing during defrosting operations of the evaporator carried out by a cycle reversal of the outdoor unit (6), to stop the circulation of the secondary fluid in the temperature modification circuit (2), and redirecting said secondary fluid to the exchanger (12) in order to maintain the secondary fluid at a certain temperature by means of a sampling of the energy heat required for said cycle in the hot water tank (4) via the condenser (8) of the indoor unit.

Description

The invention relates to a system for cooling, air conditioning or heating a building based on the principle of the heat pump and using outside air as a source of thermal energy. The system is of the type with separate heat exchange units in which, on the one hand, the compressor, the expansion device and the first exchanger in which the outside air circulates and, on the other hand, the second heat exchanger are distributed in two separate heat exchange units and at a distance from each other.

When such a system is installed for the purpose of cooling, air conditioning or heating a building (dwelling ...), one of the heat exchange units, called outdoor unit, is placed outside the building while the Another unit is placed inside the building.

Generally, this type of outdoor unit comprises an evaporator, an air inlet on a first face and an air outlet on a second face opposite to the first.

It is known that on heat pumps, the defrosting can be ensured by a cycle reversal by means of a 4-way valve on the refrigerant circuit. The said valve performs the permutation between the evaporator and the condenser of the refrigerant circuit. During this operation, energy must be supplied to the condenser which has turned into an evaporator.

Currently, the strategy for defrosting the evaporator of the outdoor unit is to reverse the refrigeration cycle and to take the defrosting energy in at least one hydraulic circuit of the heating network.

It is known that on the so-called 2-service devices providing both the heating function and the domestic hot water production function sequentially, a 3-way directional valve is used to switch the hydraulic circuits to the condenser. it can be irrigated by the heating circuit or sanitary circuit.

Usually, the tilting of a 3-way valve between the DHW circuit and the heating circuit (also ensuring the cooling and air conditioning functions) is used for this purpose. function, on the devices providing these two services. The implementation of 2 pumps can also provide the same function.

This strategy works well with an exchanger (condenser) which has a large volume of water, such as a coaxial exchanger in a buffer tank of the type described in the application. EP2080975 but, on the other hand, risks frost with low volume exchangers, such as plate heat exchangers and / or very low volume heating installations.

In the latter case, the hydraulic design of the installation must provide a system ensuring in all situations a circulation of the heating fluid and a minimum volume thereof.

A typical solution is to indicate a minimum water volume for the installation and if necessary to place a buffer tank on the return of the condenser. The operational safety of the device is also associated with a water flow control. The rules of the art also stipulate that a heating installation with a centralized regulator, which is for example the case of a heat pump system, must include at least one heat transmitter, usually a radiator, equipped with a heat pump. a non-thermostatic valve, which does not prevent the user from closing said valve but avoids its automatic closing by raising the air temperature of the room.

• Si le débit d'eau sur l'installation est faible ou nul, dans le cas par exemple d'une vanne thermostatique et de robinets fermés, il existe un risque de gel de l'échangeur (condenseur) lors du dégivrage. Le risque augmente sur des installations à faible volume d'eau. Ce risque est accentué en mi saison ou dans les habitations sensibles à l'ensoleillement ou par la présence d'appareils de chauffage individuels impliquant par exemple du bois : dans ce cas, en l'absence de besoin de chauffage des locaux, le basculement en dégivrage intervient souvent lors d'une charge sanitaire et le circuit de chauffage peut être complètement fermé.
• Lors d'une mise en route par temps froid, il donc est nécessaire de préchauffer la boucle de chauffage avec les appoints électrique afin de garantir la disponibilité de suffisamment d'énergie pour un éventuel dégivrage. Ceci est contraignant, mal vécu par l'installateur et source de gaspillage d'énergie.

This arrangement has some disadvantages:

• If the flow of water on the installation is low or zero, in the case for example of a thermostatic valve and closed valves, there is a risk of freezing of the exchanger (condenser) during defrosting. The risk increases on low volume installations. This risk is accentuated in mid-season or in houses sensitive to sunshine or by the presence of individual heaters involving for example wood: in this case, in the absence of the need for space heating, the switchover to defrosting often occurs during a sanitary load and the heating circuit can be completely closed.
• When starting up in cold weather, it is therefore necessary to preheat the heating loop with electrical connections to ensure the availability of sufficient energy for a possible defrost. This is restrictive, badly experienced by the installer and a source of energy waste.

A cooling, air conditioning or heating system according to the invention makes it possible to overcome the disadvantages noted in the state of the art, in particular by proposing to ensure the defrosting of the outdoor unit, whatever the geometry and the characteristics of the hydraulic environment of the condenser.

For the rest of the description, it is important to specify that the terms "defrosting the outdoor unit" and "defrosting the evaporator" are equivalent.

The subject of the invention is a system for cooling, conditioning or heating a building comprising a circuit for modifying the temperature of said building and a hot water heating circuit equipped with a hot water tank, said system being based on the principle of the heat pump using air as an external source and having an external heat exchange unit provided with an evaporator and an indoor unit having a condenser and for heating a secondary fluid flowing alternately in the cooling circuit. heating and the hot water heating circuit where it provides heating of a tertiary fluid supplying the balloon, through an exchanger thermally connecting the secondary and tertiary fluids.

The main characteristic of a system according to the invention is that it comprises an automatic control device allowing during defrosting operations of the evaporator carried out by a cycle reversal of the outdoor unit, to stop the circulation of the fluid. secondary circuit in the temperature modification circuit, and to redirect said secondary fluid to the exchanger to maintain the secondary fluid at a certain temperature by means of a heat energy withdrawal required for said cycle in the hot water tank via the condenser of the indoor unit. The circuit for modifying the temperature of the building may for example be constituted by a heating circuit, a cooling circuit or an air conditioning circuit. Depending on its use, the temperature modification circuit can either lower or increase the temperature of the building. Nevertheless, such a circuit for modifying the temperature is essentially used as a heating circuit in the context of the present invention.

The external heat exchange unit provides a heat exchange with the outside air and comprises at least one heat exchanger in the form of an evaporator. A system according to the invention is thus able to ensure a defrosting of this evaporator by taking a heat energy from the hot water tank via the condenser of the indoor unit. The defrosting of this evaporator is usually carried out by means of the condenser of the indoor unit connected to the temperature modification circuit, which presents risks of frost if it is too small. By using hot water stored in the flask, the condenser of the temperature change circuit is no longer exposed to freezing. However, it is not excluded that the temperature modification circuit may completely or partially substitute for the domestic hot water circuit for transiently providing the defrosting of the evaporator of the external heat exchange unit. . Indeed, the fact of ensuring the defrosting of the evaporator mainly with the hot water circulation circuit does not mean that this defrosting can not be performed with the temperature modification circuit during well identified periods. . Preferably, the temperature modification circuit is a hydraulic circuit. Preferably, a control unit controls the various streams of hot water present in the building, in particular to route the hot water stored in the flask to the condenser converted into an evaporator. Advantageously, the hot water circuit is a hot water circuit.

Preferably, a system according to the invention comprises a directional valve capable of managing the two circuits, the defrosting of the evaporator of the outdoor unit being performed in conjunction with the inversion of the refrigerating cycle, by a tilting of the valve to redirect the secondary fluid to the heat exchanger in communication with the tertiary fluid of the balloon, ensuring the permutation of hot sources of said cycle. In this way, when a need for defrosting the evaporator is detected, simultaneously with the cycle reversal of the outdoor unit, a control unit drives the valve to send hot water stored in the balloon. of sanitary water to the condenser of the circuit converted into an evaporator by the cycle inversion, in order to transmit to it the energy necessary for defrosting the evaporator of the outdoor unit, which operates as a condenser during defrosting. Advantageously, the hot water stored in the flask is sent to the condenser via an intermediate heat exchanger, such as a coil.

According to another preferred embodiment of a system according to the invention, said system comprises two separate pumps capable of managing the two circuits, the defrosting of the evaporator of the outdoor unit being performed together with the reversal of the refrigerating cycle by switching the pump of the temperature change circuit to the hot water circuit pump to redirect the secondary fluid to the heat exchanger in communication with the tertiary fluid of the balloon, ensuring the permutation of hot springs of said cycle.

Advantageously, a system according to the invention comprises means for controlling the temperature of the water stored in the balloon. In this way, the temperature of the water present in the flask can be adjusted to just what is necessary in relation to the needs of the moment, in terms of defrosting.

Another subject of the invention is a method for defrosting an evaporator of an outdoor unit of a system according to the invention.

• une étape de basculement des deux circuits vers le circuit d'eau chaude,
• une étape de dégivrage par inversion du cycle, de l'évaporateur de l'unité d'échange thermique extérieure avec l'énergie apportée au condenseur par l'eau chaude stockée dans le ballon.

The main characteristic of a system according to the invention is that it comprises the following steps,

• a step of tilting the two circuits to the hot water circuit,
• a defrosting step by inversion of the cycle, the evaporator of the external heat exchange unit with the energy supplied to the condenser by the hot water stored in the flask.

It should be noted that the switching of the two circuits to the hot water circuit can for example be achieved by means of a valve and / or pumps.

Advantageously, a method according to the invention comprises a step of controlling the temperature of the sanitary water stored in the balloon. This step of controlling the temperature of the domestic hot water stored in the flask is intended to verify that said water is well able to ensure the defrosting of the evaporator completely and satisfactorily. The control step may for example be carried out by means of measurements made with conventional temperature probes.

Preferably, a method according to the invention comprises a step of preliminary heating of the water present in the flask, if the temperature controlled in the flask is below a predetermined threshold value. Indeed, if the control step reveals that the temperature of the water is not sufficiently high, then a deicing method according to the invention implements a complementary step of heating the water to bring it to a sufficient temperature and allow it to ensure satisfactory defrosting of the evaporator.

Preferably, the preliminary heating step of the flask is carried out by means of an electrical resistance device. It is a simple heating means, proven and well controlled.

Advantageously, if the temperature controlled in the flask is lower than a predetermined threshold value, said method comprises a step of using the temperature modification circuit as a hot source. to defrost the evaporator of the outdoor unit. Indeed, if the conditions are not met at the hot water tank, then the temperature change circuit can be requested to temporarily provide defrosting of the evaporator, while waiting for the hot water tank to become operational.

Advantageously, the threshold temperature of the balloon is a function of at least one parameter to be chosen from among the characteristics of the external heat exchange unit, the capacity of the balloon and a condenser placed on the water circuit and the circuit for modifying the temperature. temperature. This threshold temperature is set taking into account the environment of the temperature and domestic hot water circuit, the structural and functional characteristics of the external heat exchange unit, the capacity of the tank and the characteristics the condenser of the indoor unit.

Another object of the invention is a building comprising a system according to the invention and allowing the implementation of a method according to the invention.

The main characteristic of a building according to the invention is that the defrosting step of the outdoor unit is carried out from a control unit which is able to select the temperature modification circuit or the control circuit. hot water to provide said defrost. Such a building thus has a dual possibility of defrosting the outdoor unit, one via the temperature modification circuit, the other via the hot water circuit. Advantageously, these two circuits can thus be used alternately, to ensure the same defrosting phase of the evaporator. According to another embodiment, one of the two circuits may be preferred to the other circuit to ensure the entire defrosting phase, as a function of economic parameters or for reasons of efficiency and efficiency. Indeed, in the case of a forecast of a strong need for hot water, it is the temperature change circuit that will be preferred to ensure the defrosting of the evaporator and thus preserve the hot water for its use original.

Advantageously, the selection of the circuit is a function of at least one parameter to be chosen from the temperature of the hot water, the temperature of the circuit for modifying the temperature, the heating rate, and the time slot of use of said circuit.

• Il rend moins sensible les pompes à chaleur à une mauvaise définition du réseau hydraulique qui risquerait d'entrainer une casse du condenseur par gel, par exemple en cas d'absence de soupape différentielle ou by-pass, ou de boucle ouverte sur un réseau avec radiateurs (têtes thermostatiques),
• Il garantit le débit d'eau et évite le gel de l'échangeur lors d'un dégivrage,
• S'il est placé sur un réseau à très faible volume d'eau, il est possible de trouver l'énergie du dégivrage dans le ballon d'eau chaude sanitaire,
• Sa mise en oeuvre peut être facilitée par temps froid au moyen d'une stratégie reposant sur un chauffage préliminaire du ballon d'eau chaude sanitaire, puis sur une autorisation de fonctionnement du module thermodynamique pour le chauffage, même si la température du circuit hydraulique de chauffage est basse. Il n'existe ainsi plus de risque de gel dans l'échangeur lors du dégivrage,
• Il évite un inconfort provoqué par la chute de température de départ en mode chauffage lors des dégivrages (particulièrement avec des générateurs à faible inertie ou de type ventilo-convecteurs en combinaison ou non avec des faibles volumes),
• Lors des périodes de production d'eau chaude sanitaire uniquement, par exemple à mi saison, il permet d'éviter d'envoyer dans le circuit de chauffage le volume d'eau à assez haute température de l'échangeur au moment du basculement de la vanne en mode dégivrage, et donc de provoquer des gênes utilisateurs pour des trains de chaleur dans les radiateurs alors qu'il n'y a pas de besoin chauffage,
• Il améliore l'efficacité de la production d'eau chaude sanitaire :
  • l'énergie contenue dans l'échangeur au moment du basculement de la vanne en mode dégivrage est envoyé dans le circuit de modification de la température et est donc perdue pour l'eau chaude sanitaire. Une partie est donc récupérable par le ballon. De plus, avec un échangeur incluant un ballon tampon (coaxial) et selon les conditions du circuit de chauffage, l'échangeur est refroidi plus que nécessaire par le flot de retour chauffage. On peut donc envisager de moduler le dégivrage entre 0 - 100 % sur l'eau chaude sanitaire ou le circuit de modification de la température afin de minimiser la consommation globale du système. Cette logique doit être associée à une sécurité du débit du circuit de modification de la température (basculement de la vanne sur l'eau chaude sanitaire).
• Les cycles de dégivrage sur ECS, accentueront la stratification du ballon et contribueront à l'amélioration de l'efficacité sur les relances.

A cooling, air conditioning or heating system according to the invention has the following advantages,

• It makes the heat pumps less sensitive to a poor definition of the hydraulic network which could cause a breakage of the gel condenser, for example in the absence of a differential or bypass valve, or open loop on a network with radiators (thermostatic heads),
• It guarantees the flow of water and avoids the freezing of the exchanger during a defrost,
• If it is placed on a network with a very small volume of water, it is possible to find the defrosting energy in the hot water tank,
• Its implementation can be facilitated in cold weather by means of a strategy based on a preliminary heating of the domestic hot water tank, then on an authorization of operation of the thermodynamic module for heating, even if the temperature of the hydraulic circuit of heating is low. There is no longer a risk of frost in the exchanger during defrosting,
• It avoids a discomfort caused by the fall of temperature of departure in heating mode during the defrostings (particularly with generators with low inertia or fan coil type in combination or not with low volumes),
• During periods of production of domestic hot water only, for example at mid-season, it makes it possible to avoid sending into the heating circuit the volume of water at relatively high temperature of the exchanger at the time of the changeover of the valve in defrost mode, and thus to cause inconvenience for heat trains in the radiators when there is no need heating,
• It improves the efficiency of domestic hot water production:
  • the energy contained in the exchanger at the time of the tilting of the valve in defrost mode is sent into the temperature modification circuit and is therefore lost for domestic hot water. Part is recoverable by the ball. In addition, with an exchanger including a buffer tank (coaxial) and according to the conditions of the heating circuit, the exchanger is cooled more than necessary by the heating return flow. We can therefore consider modulating the defrost between 0 - 100% on domestic hot water or temperature modification circuit to minimize the overall consumption of the system. This logic must be associated with a safety of the flow rate of the circuit for modifying the temperature (tilting of the valve on domestic hot water).
• The defrost cycles on DHW will accentuate the lamination of the balloon and will contribute to the improvement of the efficiency on the raises.

• La figure 1 est une vue schématique d'un bâtiment selon l'invention comprenant un système de dégivrage selon l'invention.

The following is a detailed description of a preferred embodiment of a building according to the invention as well as a deicing method according to the invention with reference to FIG. figure 1 .

• The figure 1 is a schematic view of a building according to the invention comprising a deicing system according to the invention.

Referring to the figure 1 a building 1 according to the invention comprises a cooling, air conditioning or heating system comprising a circuit in which a secondary fluid circulates, said circuit comprising a heating circuit 2 and a domestic hot water circuit 3 in communication with a heat exchanger 12 immersed in a flask 4 of domestic hot water, wherein circulates a tertiary fluid 13, said system being based on the principle of the heat pump, using air as an external source. The tertiary fluid 13 thus supplies the hot water flask 4 from a source that is an integral part of the building 1 water supply network. This heat pump also uses a thermodynamic cycle based on compression, condensation, the relaxation and evaporation of a fluid primary 11, such as for example R410A, and is intended to heat the secondary fluid of the heating circuit 2 and the hot water circuit 3 sanitary, and the tertiary fluid 13 of the balloon 4.

Such a system conventionally comprises a three-way valve capable of controlling the secondary fluid between the heating circuit 2 and the domestic hot water circuit 3 to the tertiary fluid 13 of the balloon 4. The building 1 comprises an exchange unit 6 external thermal device for ensuring a heat exchange with the outside air, said unit 6 comprising at least one heat exchanger in the form of an evaporator and a cycle reversal valve. Said building 1 also comprises an indoor unit having a condenser 8. The heating circuit 2 comprises the condenser 8 and is capable of supplying hot water with heating elements such as, for example, radiators 10 of the building 1. The evaporator of the external unit 6 being able to undergo ice accumulation phases during the different phases of operation of the cooling system, air conditioning or heating, must undergo defrosting phases to remain operational.

These defrosting phases were ensured until now by the condenser 8 of the indoor unit. However, it turned out that when said condenser 8 had a small volume, it could freeze or degrade the temperature in the heating circuit 2.

• une étape de contrôle de la température de l'eau stockée dans le ballon 4 afin de comparer ladite température à une température seuil prédéterminée. Cette étape peut consister en une étape de mesure de la température de l'eau stockée dans le ballon 4, au moyen de sondes de température conventionnelles. Si la température seuil n'est pas atteinte, une étape de préchauffage du ballon 4 peut être réalisée au moyen par exemple de résistances chauffantes 9 conventionnelles. Selon la logique choisie, une vérification des conditions de fonctionnement du circuit de chauffage 2 peut également avoir lieu afin d'autoriser le fonctionnement thermodynamique.
• une étape de détection d'un besoin en dégivrage de l'évaporateur de l'unité extérieure 6,
• une étape de dégivrage de l'évaporateur de l'unité extérieure 6 par une inversion de cycle de ladite unité extérieure 6. Lors de cette étape de dégivrage, la vanne 5 est pilotée par l'unité de commande de manière à arrêter la circulation du fluide secondaire dans le circuit de chauffage 2, et de rediriger ledit fluide secondaire vers l'échangeur 12 afin de maintenir le fluide secondaire à une certaine température au moyen d'un prélèvement de l'énergie calorifique nécessaire audit cycle dans le ballon 4 d'eau chaude via le condenseur 8 de l'unité interne. Suite à cet arrêt, la vanne 5 fait basculer le fluide secondaire vers le circuit 3 d'eau chaude sanitaire et envoie cette eau chaude vers le condenseur 8, conjointement à l'inversion du cycle frigorifique de l'unité extérieure 6. Ainsi, le dégivrage de l'unité extérieure est assuré par un prélèvement de l'énergie calorifique dans le ballon 4 d'eau chaude sanitaire,

A defrosting process of the outdoor unit according to the invention uses the condenser 8, the heat exchanger 12 and the hot water tank 4. It is assumed that such a method is controlled by a control unit. Such a method comprises the following steps,

• a step of controlling the temperature of the water stored in the flask 4 in order to compare said temperature with a predetermined threshold temperature. This step may consist of a step of measuring the temperature of the water stored in the flask 4, by means of conventional temperature probes. If the threshold temperature is not reached, a preheating step of the flask 4 can be carried out at for example conventional heating resistors 9. Depending on the logic chosen, a verification of the operating conditions of the heating circuit 2 can also take place in order to allow the thermodynamic operation.
• a step of detecting a defrosting requirement of the evaporator of the outdoor unit 6,
• a step of defrosting the evaporator of the outdoor unit 6 by a cycle reversal of said outdoor unit 6. During this deicing step, the valve 5 is controlled by the control unit so as to stop the circulation of the secondary fluid in the heating circuit 2, and to redirect said secondary fluid to the exchanger 12 in order to maintain the secondary fluid at a certain temperature by means of a sampling of the heat energy required for said cycle in the balloon 4 of hot water via the condenser 8 of the indoor unit. Following this stop, the valve 5 switches the secondary fluid to the circuit 3 of domestic hot water and sends the hot water to the condenser 8, together with the inversion of the refrigeration cycle of the outdoor unit 6. Thus, the defrosting of the outdoor unit is ensured by a removal of the heat energy in the hot water tank 4,

The defrosting process described above is exclusively carried out by the use at the hot source of the cooling circuit of the hot water stored in the tank 4. It should be noted that such a method is controlled by a suitable control unit. to take into account all the parameters inherent to the operation of the balloon 4, such as, for example, the temperature, pressure and volume of the water present in said balloon 4, as well as the parameters characterizing at a given moment, all the different constituent elements the heat pump, and in particular the outdoor unit 6. This control unit also makes it possible to control the valve 5 in order to operate the heating circuit 2 and / or the domestic hot water circuit 3.

Since the building 1 is equipped with a heating circuit 2 and a domestic hot water circuit 3, the defrosting of the outdoor unit 6 can be carried out by using as hot source indifferently said two circuits 2, 3. In this way, the two circuits 2, 3 can be used alternately over a given period, to ensure the same defrosting phase of the outdoor unit 6 on said period. According to another alternative of use of said circuits 2, 3, only one of said circuits 2, 3 is retained to ensure defrosting of the outdoor unit 6, the choice of said circuit 2, 3 being dictated by constraints, such as for example the forecast of a major sanitary use, a significant heating of the building 1, for example in cold weather.

Claims (12)

System for cooling, air conditioning or heating of a building (1) comprising a circuit for modifying the temperature of said building (2) and a hot water heating circuit (3) equipped with a balloon (4) of water said system being based on the principle of the heat pump using air as an external source and having an external heat exchange unit (6) with an evaporator and an indoor unit having a condenser (8) and to heat a secondary fluid circulating alternately in the temperature modification circuit (2) and the hot water heating circuit (3) where it provides heating of a tertiary fluid (13) supplying the balloon (4) , through an exchanger (12) thermally connecting the secondary and tertiary fluids, characterized in that it comprises an automatic control device for the defrosting operations of the evaporator carried out by an inversion of e cycle of the outdoor unit (6), stopping the circulation of the secondary fluid in the temperature change circuit (2), and redirecting said secondary fluid to the exchanger (12) to maintain the secondary fluid at a certain temperature by means of a sampling of the heat energy required for said cycle in the hot water tank (4) via the condenser (8) of the internal unit. System according to claim 1, characterized in that it comprises a directional valve (5) adapted to manage the two circuits (2, 3), and in that the defrosting of the evaporator of the outdoor unit (6) is performed in conjunction with the reversal of the refrigerating cycle, by a tilting of the valve (5) for redirecting the secondary fluid to the exchanger (12) in communication with the tertiary fluid (13) ensuring the permutation of hot sources of said cycle. System according to Claim 1, characterized in that it comprises two separate pumps capable of managing the two circuits (2, 3), and in that the defrosting of the evaporator of the outdoor unit (6) is carried out jointly with the inversion of the refrigerating cycle, by a changeover of the pump of the temperature modification circuit (2) to the hot water circuit pump (3) for redirecting the secondary fluid to the exchanger (12) in communication with the tertiary fluid (13) providing the permutation of the hot springs of said cycle. System according to any one of claims 1 to 3, characterized in that it comprises means for controlling the temperature of the water stored in the flask (4). Method for defrosting an evaporator of an outdoor unit (6) of a system according to any one of Claims 1 to 4, characterized in that it comprises the following steps, a step of switching the circuits (2, 3) towards the hot water circuit (3), - A cycle reversal defrosting step, the evaporator of the external heat exchange unit (6) with the energy supplied to the condenser (8) by the hot water stored in the balloon (4). Defrosting process according to claim 5, characterized in that it comprises a step of controlling the temperature of the water stored in the flask (4), Defrosting process according to claim 6, characterized in that it comprises a step of preliminary heating of the water present in the flask (4), if the temperature controlled in the flask (4) is lower than a predetermined threshold value. Defrosting process according to Claim 7, characterized in that the preliminary heating step of the flask (4) is carried out by means of an electrical resistance device (9). Defrosting process according to claim 8, characterized in that if the temperature controlled in the flask (4) is lower than a predetermined threshold value, said method comprises a step of using the temperature modification circuit (2) as a source hot to defrost the evaporator of the outdoor unit (6). Defrosting process according to any one of Claims 6 to 9, characterized in that the threshold temperature of the flask (4) is a function of at least one parameter to be chosen from the characteristics of the external heat exchange unit (6). ), the capacity of the balloon (4) and a condenser (8) placed on the water circuit (3) and the temperature modification circuit (2). Building (1) comprising a system according to any one of claims 1 to 4 for carrying out a method according to any one of claims 5 to 10, characterized in that the step of defrosting the outdoor unit (6) is made from a control unit which is adapted to select the temperature change circuit (2) or the hot water circuit (3) to provide said defrost. Building according to Claim 11, characterized in that the selection of the circuit (2, 3) is a function of at least one parameter to be chosen from the temperature of the hot water, the heating flow rate, the temperature of the circuit for modifying the the temperature (2) and the time slot of use of said circuit (2, 3).

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