EP4617572A1

EP4617572A1 - Air conditioning system of an indoor environment of a building

Info

Publication number: EP4617572A1
Application number: EP25161918.5A
Authority: EP
Inventors: Cristian ZAMBRELLI; Alberto Benecchi; Cristina BRONZONI
Original assignee: Immergas SpA
Current assignee: Immergas SpA
Priority date: 2024-03-12
Filing date: 2025-03-05
Publication date: 2025-09-17

Abstract

An air-conditioning plant (100) for an internal environment of a building, comprising:
a hydronic system (110) comprising a primary water circuit (30);
an air-conditioning system (120);
a hybrid system (130), in turn comprising:
- a boiler (131) operatively associated with the hydronic system (110), said primary circuit (30) having extension partly through said boiler (131);
- a heat pump (132) operatively associated with the air-conditioning system (120);
- a control unit (133) configured to enable the exclusive operation of the boiler (131) or of the heat pump (132) or the combined operation of the boiler (131) and the heat pump (132).

Description

The present invention relates to an air-conditioning plant for an internal environment of a building. In particular, the air-conditioning plant is of the mixed air/water type and exploits the use of a hybrid system with boiler and heat pump.
As is known, in recent years hybrid systems have been introduced on the air-conditioning market which allow the use of at least two generators, typically boiler and air/water heat pump, which allow an improvement in the efficiency of the heating system and, sometimes, also the possibility of using the water system for summer air-conditioning.
Hybrid systems are widely used on water systems with radiators, which have the greatest efficiency with high temperatures of the heating fluid, but this limits the operation of the heat pump, which has its maximum efficiency with low fluid temperatures, when the external temperatures are higher than 0 °C so as to guarantee an adequate efficiency relative to the boiler generator.
Radiant floor systems, combined with a hybrid system, solve the problem of the air/water heat pump efficiency, since they work with low setpoint temperatures of the delivery fluid, but are characterised by a high inertia that makes the programming of different environment sets on several time slots less effective.
On both systems there would not be a possibility of carrying out the summer air-conditioning phase without a system modification such as the insertion of fan coils on the radiator systems or the insertion of a dehumidifier on floor systems.
Fan coil systems are an intermediate solution, but hardly used in homes due to noise and non-optimal comfort.
In this context, the technical task underlying the present invention is to propose an air-conditioning plant for an internal environment of a building which obviates the drawbacks in the prior art as described above.
In particular, the object of the present invention is to provide an air-conditioning plant, in which the heat pump has a lower use limitation relative to the known solutions.
Another object of the present invention is to propose an air-conditioning plant which is versatile and efficient.
The stated technical task and specified objects are substantially achieved by an air-conditioning plant for an internal environment of a building comprising the technical characteristics disclosed in one or more of the appended claims.
Further characteristics and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of a preferred but non-exclusive embodiment of an air-conditioning plant for an internal environment of a building, as shown in the attached drawings, in which:

Figure 1 shows an air-conditioning plant for an internal environment of a building, according to the present invention, in a schematic view;
Figure 2 shows a first integrative embodiment of the air-conditioning plant of Figure 1, in a schematic view;
Figure 3 shows a second integrative embodiment of the air-conditioning plant of Figure 1, in a schematic view;
Figure 4 shows a schematic circuit view of the heat pump of the air-conditioning plant of Figure 2 or 3;
Figure 5 shows a schematic circuit view of the hydronic system of the air-conditioning plant of Figure 2.

With reference to the figures, number 1 denotes an air-conditioning plant for an internal environment of a building. The air-conditioning plant is in particular of the mixed air-water type.
The air-conditioning plant 100 comprises a hydronic system 110 and an air-conditioning system 120. That is, the air-conditioning plant 100 is a hybrid multi-split air-water plant.
As is known, the hydronic system is capable of distributing thermal and/or cooling energy, using water as a thermal convection fluid.
The air-conditioning plant 100 comprises a hybrid system 130. The hybrid system 130 comprises a boiler 131 and a heat pump 132. In particular, the two devices cooperate for the operation of the air-conditioning plant 100. The boiler 131 is operatively associated with the hydronic system 110. The hydronic system 110 comprises a primary water circuit 30 which partly extends through the boiler 131 so that the water therein is heated to then be sent to terminals of the hydronic system 110. In particular, the primary circuit 30 includes a delivery duct 32 for the hot water to terminals of the hydronic system and a return duct 31 of the water from the terminals.
The boiler 131 comprises components of known type, therefore not described in detail. By way of explanation, the boiler 131 comprises a burner in which a combustion occurs which generates combustion fumes, a fan to supply ambient air to the burner, at least one portion of the fuel gas supply pipe to the burner and a heat exchanger crossed by the primary water circuit 30. In the heat exchanger, the heat exchange occurs between the fumes produced by the burner and the water of the primary circuit 30.
Appropriately, the boiler 131 comprises a combustion fumes outlet.
In more detail of the primary water circuit 30, the water returns from the terminals of the hydronic system 110 through the return duct 31 and passes through the boiler 131 in which it is heated. At this point, the heated water leaves the boiler 131 through a delivery duct 32, moving towards the terminals of the hydronic system. The terminals can be for example radiators or a floor system.
The heat pump 132 is operatively associated with the air-conditioning system 120. As is known, the heat pump 132 can operate in heating mode or in cooling mode.
In this case, the heat pump is said to be in air/air mode. In fact, it exchanges heat between the external air and the internal air to be air-conditioned by means of a refrigerant fluid. If operating in heating mode, it extracts heat from the external air and heats the air of the internal environment; if operating in cooling mode, it extracts heat from the air of the internal environment and transfers heat to the external air.
The heat pump 132 comprises components of known type, therefore not described in detail. By way of explanation, the heat pump 132 comprises a refrigerant fluid circuit 11. Such a circuit 11 passes through a first heat exchanger 12, a compressor 13, a second heat exchanger 14 and a throttling valve 15 (isoenthalpic, in the embodiment shown it is an electronic expansion valve EEV).
The first heat exchanger 12 exchanges heat with the outside, in particular with the external air, instead the second heat exchanger 14 exchanges heat with the air of the internal environment.
In heating mode, the refrigerant fluid evaporates in the first heat exchanger 12, passing from the liquid phase to the gaseous phase. The first heat exchanger 12 is generally indicated as an "evaporator". Hereinafter, the term evaporator 12 is thus used to indicate the first heat exchanger 12.
From such an evaporator 12, the refrigerant fluid is sent from a compressor 13 to a second heat exchanger 14, in which the refrigerant fluid condenses, passing from the gaseous state to the liquid state, transferring heat to the air of the internal environment. The second heat exchanger 14 is generally indicated as a "condenser". Hereinafter, the term condenser 14 is thus used to indicate the second heat exchanger 14. In summary, the compressor 13 has the function of circulating the refrigerant fluid in the circuit 11, sucking it from the evaporator 12 in the form of gas and compressing it so as to convey it to the condenser 14, at high pressure. Any type of compressor 13 which involves volumetric compression can be used.
The refrigerant fluid circuit 11 also has a throttling valve 15, which determines the necessary and sufficient pressure drop to maintain the pressure of the refrigerant fluid at the desired values of the evaporator 12 and the condenser 14.
Vice versa in cooling mode.
The hybrid system 130 comprises a control unit 133 configured to enable the exclusive operation of the boiler 131 or of the heat pump 132 or the combined operation of the boiler 131 and the heat pump 132.
In the preferred embodiment, the control unit 133 is controlled by means of an interface on the boiler 131.
In particular, the selection can take place on the basis of one or more predetermined criteria, which are known to a person skilled in the art. For example, one or more adjustment algorithms can be used.
In particular, the control unit 133 is configured to select one or both of the generators to be activated on the basis of an energy and/or economic convenience algorithm.
In addition or alternatively, a verification of the correct and rapid full operation of the system can take place by managing the modulation of the two generators.
In particular, the control unit 133 is configured to impose the target temperatures of the delivery of the generators.
The selection logic is therefore strongly dependent on the environment to be air-conditioned and the surrounding conditions. In any case, it is among the logic that the person skilled in the art knows and uses in common practice.
In an embodiment, the hydronic system 110 comprises a storage tank 70. Preferably, the heat pump 132 is also operatively associated with the tank 70 to heat the water contained therein.
Preferably, the heat pump 132 is configurable at least in a first operating condition, in which it is operatively active on the air-conditioning system 120, and a second operating condition, in which it is operatively active on the hydronic system 110, in particular on the tank 70.
In the first condition, the heat pump 132 has an air/air type operation. In the second condition, the heat pump 132 has an air/water type operation. Preferably, the control unit 133 is configured to enable the operation of the heat pump 132 in the first condition or in the second condition.
Preferably, the heat pump 132 is also configurable in a third operating condition, in which it is operatively active on both systems 110, 120. That is, in the second operating mode, the heat pump 132 operates on both the air-conditioning system 120 and on the hydronic system 110, in particular on the tank 70.
Preferably, the control unit 133 is configured to enable the operation of the heat pump 132 in the first condition or in the second condition or in the third condition.
In this embodiment, the refrigerant circuit 11 comprises at least a first-type branch 11a, 11b and a second-type branch 11c arranged in parallel. The first-type branch 11a, 11b is operatively associated with the air-conditioning system 120, while the second-type branch 11c is operatively associated with the hydronic system 110, in particular with the tank 70. Preferably, the control unit 133 is configured to enable the exclusive operation of the first-type branch 11a, 11b (i.e., use the heat pump 132 exclusively for the air-conditioning system 120, first operating condition) or of the second-type branch 11c (i.e., use the heat pump 132 exclusively for the hydronic system 110, in particular the tank 70, second operating mode). Preferably, it can enable the combined operation of the two types of branches 11a, 11b, 11c (i.e., use the heat pump 132 for both systems 110, 120, third operating mode).
That is, the control unit 133 is configured to enable the operation of the first-type branch 11a, 11b and/or the second-type branch 11c.
In the embodiment shown, there are three branches 11a, 11b, 11c, in particular divided into two first-type branches 11a, 11b and one second-type branch 11c. Such a choice is purely arbitrary and can be modified according to the specific needs of the plant.
In the embodiment shown, the branch 11a, 11b, 11c associated with the tank 70 extends partly through the tank 70. Alternatively, it externally laps or passes near the tank 70.
Preferably, the second exchanger 14 is total.
Preferably, each branch 11a, 11b, 11c has a second exchanger 14 thereof. Preferably, each branch 11a, 11b, 11c has a throttling valve 15 thereof.
In accordance with an embodiment, shown in Figure 2, the tank 70 is arranged along the primary water circuit 30, in particular on the return branch in the boiler 131. The tank 70 has an inlet 71 for the water to be heated (cold water) and an outlet 72 for the heated water (hot water).
In the preferred embodiment, the tank 70 is integrated inside the boiler 131.
Preferably, a three-way valve 33 is arranged along the primary water circuit 30. The valve 33 has an inlet 33a for the water heated by the boiler, a first outlet 33b for the delivery of the heating water and a second outlet 33c communicating with a fourth heat exchanger 34. The operation of the three-way valve 33 is of the exclusive type. That is, the first outlet 33b and the second outlet 33c are alternatively enabled and cannot be crossed by water at the same time: the water entering the valve 33 is sent to either the heating system or to the exchanger 34 for producing DHW. In said fourth heat exchanger 34, the hot water transfers heat to a domestic water circuit 80. The exiting cold water is sent to the primary circuit 30 upstream of the tank 70 to be heated again. That is, the tank 70 is in series with the return of the water of the primary circuit 30 from the terminals.
In this embodiment, after the passage in the boiler 131 the hot water encounters the three-way valve 33: the water can be sent to either the delivery duct 32 of the plant by means of the first outlet 33b or to the fourth heat exchanger 34, where domestic hot water is produced, by means of the second outlet 33c.
With the hybrid system 130 of this embodiment, all the prerogatives of the previous system are maintained and, in addition, it is possible to have an increase in performance since the heat pump contributes to preheating the water stored in the tank 70, working in air/water mode. Preheating, when working on the domestic side, ensures a faster supply of domestic hot water with a higher efficiency than known solutions, given by the use of a heat pump for the heating and temperature maintenance phase of the storage. Another advantage is that of being able to produce domestic hot water also with the heat pump 132, increasing the efficiency of the domestic hot water production system and avoiding frequent ignitions of the boiler 131 for small withdrawals.
In accordance with an alternative embodiment, shown in Figure 3, the storage tank 70 is arranged along a domestic water circuit 80. In particular, the domestic water circuit 80 is distinct from the primary circuit 30, that is, there is no heat exchange between water of the primary circuit 30 and water of the domestic water circuit 80 for the production of DHW, as instead occurs in the previously described embodiment, of Figure 2. In this case, the tank 70 is used exclusively for producing domestic hot water.
In this embodiment, the boiler 131 and the heat pump 132 configured in the second operating condition (i.e., in air-water mode) are both operatively active on the tank 70 for heating the water contained therein. Preferably, the control unit 133 is configured to enable the exclusive and alternative operation of the boiler 131 or heat pump 132 on the tank 70. Preferably, the air-conditioning plant 100 comprises means for detecting (not shown) the temperature of the water inside the tank 70. The control unit 133 is configured to enable the exclusive and alternative operation of the boiler 131 or heat pump 132 on the basis of the detected temperature. In particular, the control unit 133 is configured to:

if the detected temperature value is comprised within a first range, enable the exclusive operation of the heat pump 132 (in particular, in the second operating condition);
if the detected temperature value is comprised within a second range, enable the exclusive operation of the boiler 131.

The second range is at least partly, but preferably totally, greater than the first range.
This allows a hybrid heating of the domestic storage which improves the performance of the entire plant. In fact, the heat pump 132 is used for the heating phase at medium temperatures, increasing the efficiency thereof, while for heating at high temperatures it is managed through the use of the boiler 131.
In the preferred embodiment, the tank 70 is integrated inside the boiler 131.
The invention achieves important advantages.
The proposed hybrid system allows to combine the efficiency of a heat pump in air/air mode, which can therefore be used in integration even on radiator systems without inefficiency, and the maintenance of comfort in heating, given by the hydronic system.
In low temperature radiant systems, this type of mixed hybrid system greatly improves the rapid operational start-up speed of the radiant system, allowing the latter to be used as if it were a radiator system with several programming time slots of the environment set. So much so that a system shut-down is allowed, which is generally not performed due to inertia problems.
Finally, the possibility of cooling using the heat pump in air/air mode is provided, always by means of control from the boiler interface.
In addition, the possibility of selecting different operating modes of the heat pump increases the versatility and efficiency of the plant. In particular, the possibility of using the heat pump in air/water mode as well as air/air. The embodiment of Figure 2 maintains all the prerogatives of the basic hybrid system, with the addition of the possibility of increasing performance on the domestic side since the heat pump contributes to preheating the water stored in the storage. In this case, the heat pump works in air/water mode. Preheating, when working on the domestic side, ensures a faster supply of domestic hot water, as already occurs in some boilers, but with a higher efficiency given the use of the heat pump for the heating and temperature maintenance phase of the storage.
Furthermore, the possibility of operating the pump in the two operating modes ensures a high level of environmental comfort: this would not be possible with the full-air system alone, going to work on the preheating of the plant return.
Furthermore, another advantage is given by the positioning of the preheating storage in series with the return of the water system; this layout allows the heat pump to work with lower temperatures than those used in direct supply, increasing its individual performance and consequently of the plant. Furthermore, the boiler will add only the portion of energy necessary for the integration on the plant.
The embodiment of Figure 3 allows a hybrid heating of a domestic storage, i.e., exclusively used for the production of domestic hot water. In this case, the domestic storage is heated in a hybrid manner by the heat pump in air/water mode and by the boiler, while the part related to environmental comfort is managed as in the basic hybrid system (boiler for hydronic system and air/air heat pump for air-conditioning system).
In particular, the heat pump is used for the heating phase up to medium temperatures, increasing the efficiency thereof, while the heating at high temperatures is managed through the boiler. Another peculiarity of the hybrid system of this embodiment is the possibility of managing the load on the basis of need. In fact, by monitoring the temperature inside the storage, it is possible to determine an instantaneous use factor which is used for the selection of the generator to be used for heating the fluid inside the domestic storage.

Claims

An air-conditioning plant (100) for an internal environment of a building, comprising:
a hydronic system (110) comprising a primary water circuit (30);

an air-conditioning system (120);

a hybrid system (130), in turn comprising:
- a boiler (131) operatively associated with the hydronic system (110), said primary circuit (30) having extension partly through said boiler (131);

- a heat pump (132) operatively associated with the air-conditioning system (120);

- a control unit (133) configured to enable the exclusive operation of the boiler (131) or of the heat pump (132) or the combined operation of the boiler (131) and the heat pump (132).
The air-conditioning plant (100) according to claim 1, wherein the hydronic system (110) comprises a storage tank (70), said heat pump (132) also being associated with said tank (70) of the hydronic system (110).
The air-conditioning plant (100) according to claim 2, wherein said heat pump (132) can be configured in at least:
- a first operating condition, in which it is operatively active on the air-conditioning system (120);

- a second operating condition, in which it is operatively active on the hydronic system (110) to heat water in the tank (70).
The air-conditioning plant (100) according to claim 2 or 3, wherein the heat pump (132) comprises a refrigerant fluid circuit (11), said circuit (11) comprising at least a first-type branch (11a, 11b) and at least a second-type branch (11c) arranged in parallel, said at least a first-type branch (11a, 11b) being operatively associated with the air-conditioning system (120), said at least a second-type branch (11c) being operatively associated with the hydronic system (110).
The air-conditioning plant (100) according to claim 4, wherein the control unit (133) is configured to enable the operation of the first-type branch (11a, 11b) and/or the second-type branch (11c).
The air-conditioning plant (100) according to any one of claims 2 to 4, wherein the tank (70) is arranged along the primary circuit (30), said hydronic system (110) comprising a three-way valve (33) arranged along the primary circuit (30) downstream of the boiler (131), said three-way valve (33) having an inlet (33a) for the water heated by the boiler (131), a first outlet (33b) for sending water towards terminals of the hydronic system (110) and a second outlet (33c) communicating with a fourth heat exchanger (34), said first outlet (33b) and said second outlet (33c) being alternatively selectable, a heat exchange with a domestic hot water circuit (80) occurring in said heat exchanger (34).
The air-conditioning plant (100) according to any one of claims 2 to 4, wherein the tank (70) is arranged along a domestic hot water circuit (80), said boiler (131) and said heat pump (132) configured in the second operating condition both being operatively active on the tank (70) for heating the water contained therein.
The air-conditioning plant (100) according to claim 7, wherein the control unit (133) is configured to enable the exclusive and alternative operation of the boiler (131) or heat pump (132) on the tank (70).
The air-conditioning plant (100) according to claim 7 or 8, comprising means for detecting the temperature of the water inside the tank (70), said control unit (133) being configured to enable the exclusive and alternative operation of the boiler (131) or heat pump (132) on the basis of the detected temperature.
The air-conditioning plant (100) according to claim 9, wherein the control unit (133) is configured to:
if the detected temperature value is comprised within a first range, enable the exclusive operation of the heat pump (132);

if the detected temperature value is comprised within a second range, at least partially greater than the first range, enable the exclusive operation of the boiler (131).