EP4365503A1

EP4365503A1 - A heat pump with a bladeless fan heat exchanger

Info

Publication number: EP4365503A1
Application number: EP23202106.3A
Authority: EP
Inventors: Marco Molteni; Roberto Alessandrelli
Original assignee: Ariston SpA
Current assignee: Ariston SpA
Priority date: 2022-11-07
Filing date: 2023-10-06
Publication date: 2024-05-08
Also published as: CN117989751A

Abstract

A heat exchanger (100) in an external unit of a heat pump (1), comprises a heat exchange unit (102), an air conveyor (105) operable to convey an air flow through an air channel system (104) of the heat exchange unit (102), wherein the air conveyor (105) comprises a conveying channel (106) with an annular outlet slot (108), a driving air fan (109) for sucking a driving air flow (110) into the conveying channel (106) and expelling the driving air flow (110) from the conveying channel (106), through the annular outlet slot 108, in the form of an annular air blade so as to generate an aerodynamic depression which takes in a driven air flow (113) with a higher flow rate than the flow rate of the driving air flow (110), wherein the outlet slot (108) is arranged at the heat exchange unit (102), so that at least the driven air flow (113) crosses the air channel system (104).

Description

The invention relates to a heat exchanger, for example in a heat pump, for example for heating and/or cooling air and/or water, for example in a plant for heating and/or cooling rooms and/or water.
A heat pump comprises a circuit for the circulation of a refrigerant fluid, an evaporator (consisting of a first heat exchanger) placed in the circuit, a compressor placed in the circuit downstream of the evaporator, a condenser (consisting of a second heat exchanger) placed in the circuit downstream of the compressor, and an expansion valve placed in the circuit downstream of the condenser and upstream of the evaporator. The indications "downstream" and "upstream" refer to the circulation direction of the refrigerant fluid in at least one operating mode. The compressor is operable to suck in the refrigerant fluid in the gaseous phase and at low pressure from the evaporator, compress the refrigerant fluid, and push it into the condenser. Inside the condenser, the compressed refrigerant fluid releases heat and condensation at high pressure. After the exit from the condenser, the refrigerant fluid passes through the expansion valve which decompresses it, bringing the refrigerant fluid to a depressurized liquid phase with a possibly lower amount of gaseous phase. Still due to the suction effect of the compressor, the depressurized liquid refrigerant fluid is conveyed into the evaporator where the refrigerant fluid absorbs heat and evaporates at low pressure, before being sucked in and compressed again by the compressor.
The refrigerant fluid changes state inside the evaporator, switching from liquid to gaseous by absorbing heat, and inside the condenser, switching from gaseous to liquid by yielding heat. The space where the evaporator is located is thus cooled, whereas the space where the condenser is located is heated.
It is further known to connect the compressor in the circuit by the interposition of a (four-way) switching valve which allows inverting the compression and circulation direction of the refrigerant fluid and thus switching the first heat exchanger from evaporator to condenser and the second heat exchanger from condenser to evaporator, allowing both cooling and heating the spaces in which the first and second heat exchangers are located.
Known heat pumps, described above, can be used in a heating mode, e.g., in winter months, taking heat from the external air and bringing heat into a building.
In this case, the refrigerant fluid crosses the expansion valve and becomes a liquid-vapor mixture at low pressure, then enters into the evaporator, placed outside, where it absorbs heat until it becomes vapor at low temperature, which vapor is then sucked in and compressed by the compressor with the consequent temperature increase, and the hot and compressed vapor is pushed from the compressor outlet into the condenser, where it yields heat, e.g., to a water circuit for heating an indoor environment, and changes phase again from gas to liquid releasing the liquefaction heat. The liquid refrigerant fluid returns to the expansion valve and the cycle is repeated.
By inverting the cooling cycle, e.g., through the (four-way) switching valve, the same heat pump can be used in a cooling mode, e.g., in the summer months, where the refrigerant fluid evaporates in the internal heat exchanger and condenses in the external heat exchanger.
The heat exchange conditions between air and refrigerant fluid, in both an outdoor and indoor environment, greatly affect both the energy efficiency of the heat pump and the external and internal structural configurations of the heat exchangers and, therefore, of the external and internal units of the heating and/or cooling systems.
In the prior art it is known to provide an axial fan for moving an air flow through the air-refrigerant fluid heat exchanger, for example a surface heat exchanger, e.g., finned, which allows a heat exchange between the air flow and the refrigerant fluid through the surfaces that separate the two fluids.
Axial fans, in the context of heat exchanger applications, generate an axial air flow component, a radial air flow component, and a tangential air flow component.
The air flow component useful for the heat exchange generated by an axial fan is only the axial component, since it contributes to the air flow rate value, while the radial and tangential flow components do not contribute to the air flow rate nor to the heat exchange of the air-refrigerant fluid exchanger.
The magnitude of the radial and tangential components of the air flow depends, as a first approximation, on the rotation speed and geometry of the fan. Only under idealized conditions, which are not actually achievable, the air velocity in the fan suction region is equal to the axial velocity component of the air downstream of the fan.
Considering a positioning of the fan downstream of the heat exchange unit (heat exchange assembly understood as the set of ducts and heat exchange surfaces crossed by the two or more fluid flows involved in the heat exchange), even the vector of the air flow in the suction phase is not ideally axial, but disturbed by the heat exchange unit itself and by other structural components necessary, for example, for the stable and safe assembly of the fan itself.
A similar situation also occurs downstream of the fan due to the presence of a protective grille (necessary to protect the fan blades from external influences and to protect users from the risk of injury caused by the rotating blades). The protective grille also affects the flow generated by the axial blade fan, making it further uneven and increasing the non-axial components thereof. The work done by the fan to generate the non-axial flow components (and which do not contribute to the flow rate and heat transfer) is a source of unnecessary operating costs, as well as undesired noise and vibrations.
The geometry of the axial fan and the need for a protective grille further are a source of undesirable sizing and aesthetic constraints.
Moreover, in very humid environmental conditions or in the case of accumulation of moisture when defrosting the evaporator heat exchanger of a heat pump during winter operation, the fan blades can accumulate a layer of ice and frost resulting in the risk of blocking the rotation of the heat exchanger air fan impeller.
Therefore, it is the object of the present invention to provide an improved heat exchanger and heat pump having features such as to overcome at least some of the disadvantages of the prior art.
Within the scope of the general purpose, it is a particular object of the invention to provide an improved heat exchanger and heat pump having features such as to reduce the structural constraints and safety measures required by rotary blade fans, as well as to reduce the resistance to the air flow through the heat exchange unit.
It is a further particular object of the invention to provide a heat exchanger and a heat pump having features such as to make the air flow through the heat exchange unit more uniform and, possibly, less noisy.
It is a further particular object of the invention to provide a heat exchanger and a heat pump having features such as to generate an air flow through the heat exchange unit having small radial and tangential flow components as compared to the prior art.
It is a further particular object of the invention to provide a heat exchanger and a heat pump having features such as to generate an air flow through the heat exchange unit having an increased flow rate with the same electric power absorbed by the air conveyor.
It is a further particular object of the invention to provide a heat exchanger and a heat pump having a simplified structure.
It is an even further object of the invention to overcome the risk of freezing the fan resulting in risk of blocking the rotation of the impeller of the air fan.
These and other objects are achieved by a heat exchanger, in particular a heat pump, according to claim 1. The dependent claims relate to advantageous and preferred embodiments.
According to an aspect of the invention, a heat exchanger, in particular for a heat pump, comprises:

a support structure,
a heat exchange unit connected to the support structure and having a fluid channel system and an air channel system in heat exchange communication with the fluid channel system,
an air conveyor connected to the support structure and operable to convey an air flow through the air channel system of the heat exchange unit, where the air conveyor comprises:
a tubular conveying channel extending from an inlet opening to an annular outlet slot (not necessarily circular),
a driving air fan placed in the conveying channel and operable to suck in a driving air flow through the inlet opening into the conveying channel and expel the driving air flow from the conveying channel, through the annular outlet slot, in the form of an annular air blade (not necessarily circular) in a driving flow direction,
optionally, an annular guide surface with a continuous convex curvature, formed downstream along the entire annular outlet slot,

so as to generate a depression due to the aerodynamic and/or Coand
effect, which takes in a driven air flow with a higher flow rate than the driving air flow, in a driven flow direction,
where the annular outlet slot and, if provided, the annular guide surface are arranged at the heat exchange unit, so that at least the driven air flow crosses the air channel system, where the driving air fan is arranged outside and at a distance from the driven air flow and the heat exchanger has no impellers with blades at the driven air flow.

The suggested configuration allows the generation of a driven air flow due to the ejector effect and the Coand
effect which is more uniform than the air flows generated by a bladed fan in the heat exchangers of the prior art and which also obviates the presence of rotating blades at the heat exchange unit.
Depending on the position of the annular outlet slot upstream or downstream of the heat exchange unit, the air flow useful for heat exchange only consists of the driven air flow (position of the annular outlet slot downstream) or the sum of the driving and driven air flows (position of the annular outlet slot upstream).
The absence of the fan with rotating blades at the heat exchange unit, and thus within the air flow directly involved in the heat exchange, reduces the structural constraints of the heat exchanger and the necessary safety measures.
In particular, it is possible to reduce or completely eliminate the resistance to the flow due to the very narrow safety grilles of the prior art and to the support structure of the fans of the prior art.
Due to the absence of rotating blades in the generated air flow, the air flow itself has much smaller or almost absent radial and tangential components.
Due to the greater directional uniformity of the air flow generated and by virtue of the multiplication effect of the flow rate, with the same electrical power absorbed by the conveyor, both the flow rate of air useful for the heat exchange and the energy efficiency of the heat exchanger, in terms of lower electrical energy consumption of the conveyor with the same flow rate of air generated, are increased.
The absence of an impeller with rotating blades at the heat exchange unit also allows enlarging the heat exchange unit with the same dimensions as the external housing and simplifying the entire structure of the heat exchanger.
Moreover, the heat exchanger configuration according to the invention obviates the risk of freezing the fan blades resulting in the risk of operational interruptions due to freezing.
According to a further aspect of the invention, a heat pump comprises:

a circuit for circulating a refrigerant fluid,
a first heat exchanger placed in the circuit and forming an evaporator,
a compressor placed in the circuit downstream of the first heat exchanger,
a second heat exchanger placed in the circuit downstream of the compressor and forming a condenser,
an expansion device placed in the circuit downstream of the second heat exchanger,
an electronic control system controlling the compressor, the expansion device, the first heat exchanger, and the second heat exchanger,
where:
- the compressor is operable to suck in the refrigerant fluid in the gaseous phase and at low pressure from the evaporator, compress the refrigerant fluid, and push it into the condenser,
- in the condenser, the compressed refrigerant fluid releases heat and condenses at high pressure,
- after leaving the condenser, the refrigerant fluid passes through the expansion device which depressurizes it,
- the refrigerant fluid depressurized by the expansion device enters into the evaporator where it absorbs heat and evaporates at low pressure, before being sucked in and compressed again by the compressor,

The advantages described with reference to the heat exchanger also similarly apply to the heat pump. Further synergistic advantages concern greater freedom in designing the structure and dimensioning the external unit of the heat pump, as well as greater freedom in choosing the shape, structure, and aesthetics of the internal and external units of the heat pump.
With particular advantage, the heat exchanger according to the invention can be implemented in an external unit of the heat pump.

Brief description of the drawings

In order to better understand the invention and appreciate the advantages thereof, some non-limiting embodiments thereof will be described below with reference to the accompanying drawings, in which:

figures 1, 2, 3, 4 are perspective views of external units of heat pumps with a heat exchanger according to embodiments of the invention,
figures 5, 6, 7 are diagrammatic perspective views of an air conveyor of the heat exchanger according to embodiments,
figure 7A is a diagrammatic sectional view taken along the section plane 7A-7A in figure 7,
figure 8 is an exploded perspective view of an external unit of a heat pump, comprising a heat exchanger according to an embodiment,
figures 9, 10, 11 are a perspective view (figure 9), a side view (figure 10) and an exploded view (figure 11) of an external unit of a heat pump, comprising a heat exchanger according to an embodiment,
figures 12, 13, 14, 15, 16, 17 are diagrammatic views of external or internal units of heat pumps having a heat exchanger according to embodiments of the invention,
figure 18 shows a heat pump according to an embodiment of the invention,
figure 19 shows a heat pump according to a further embodiment,
figures 20, 21, 22 show an air entrainment effect depending on the absence (figure 20), presence (figure 21), and presence with divergent convex curvature (figure 22) of a guide surface.

Description of embodiments of the heat exchanger 100

With reference to the figures, a heat exchanger 100, in particular for a heat pump 1, comprises:

a support structure 101,
a heat exchange unit 102 connected to the support structure 101 and having a fluid channel system 103 and an air channel system 104 in heat exchange communication with the fluid channel system 103,
an air conveyor 105 connected to the support structure 101 and operable to convey an air flow through the air channel system 104 of the heat exchange unit 102,

air conveyor

a tubular conveying channel 106 extending from an inlet opening 107 to an annular outlet slot 108 (not necessarily circular),
a driving air fan 109 placed in the conveying channel 106 and operable to suck in a driving air flow 110 through the inlet opening 107 into the conveying channel 106 and expel the driving air flow 110 from the conveying channel 106, through the annular outlet slot 108, in the form of an annular air blade (not necessarily circular) in a driving flow direction 111,
optionally, an annular guide surface 112 (not necessarily circular) with convex continuous curvature, formed downstream of the annular outlet slot 108 (in the direction of the driving air flow 111) and along the entire annular extension of the annular outlet slot 108, so as to generate a depression due to the aerodynamic and/or Coand
effect, which takes in a driven air flow 113 with a greater flow rate than the driving air flow 110 in a driven air flow direction 114,

where the outlet slot 108 and, if provided, the guide surface 112 are arranged at the heat exchange unit 102, so that at least the driven air flow 113 crosses the air channel system 104,
where the driving air fan 109 is arranged outside and at a distance from the driven air flow 113 and the heat exchanger 100 has no impellers with blades at the driven air flow 113.

According to an embodiment, the annular outlet slot 108 and the guide surface 112 are formed together in a single tubular closed-loop structure 115 (not necessarily circular) mounted to the support structure 101.
According to an embodiment, the guide surface 112 is formed by, or forms, a peripheral edge 116 of an external housing 117 of the heat exchanger 100 delimiting an air outlet opening 118 of the external housing 117.
According to embodiments, the annular outlet slot 108 and/or the tubular closed-loop structure 115 has a circular shape ( figures 1 , 8) or oval shape ( figure 2 ) or polygonal shape, e.g., rectangular or square ( figure 4 ), preferably with rounded corners. This allows adapting the sectional shape of the air flow, at least at the heat exchange unit 102, to the shape of the heat exchange unit 102 itself, and adapting the external dimensions of the heat exchange unit 102 to the space conditions of the housing 117 of the heat exchanger 100.
According to an embodiment, the conveying channel 106 is configured to expel the driving air flow 110 with a substantially uniform, i.e., constant, flow rate along the annular outlet slot 108. This is particularly advantageous in the case of a circular outlet slot 108.
According to an alternative embodiment, the conveying channel 106 is configured to expel the driving air flow 110 with a non-uniform flow rate, i.e., not constant, along the annular outlet slot 108. This allows compensating for potential non-uniformity of the driven air flow 113 in the case of a non-circular shape of the outlet slot 108.
A local slowdown of the driving air flow 110, for example at corners or regions of the outlet slot 108 with a small radius of curvature (which can be achieved by targeted shaping of the inner section of the conveying channel 106), reduces the local divergence trend of driven air flow 113.
Otherwise, a local increase in flow rate, for example at corners or regions of the outlet slot 108 with a small radius of curvature (which can be achieved by shaping the inner section of the conveying channel 106 in a targeted manner), ensures the presence of a sufficient amount of driven air for the heat exchange even at the margins of the overall dimensions of the heat exchange unit 102.
Advantageously, the annular outlet slot 108 and/or the tubular closed-loop structure 115 extend in a single conveyor plane 119, ( figures 5, 6, 7 , 8 ) substantially orthogonal to the driven flow direction 114.
According to embodiments, the air conveyor 105 can comprise two or more of said annular outlet slots 108 and/or two or more of the tubular closed-loop structures 115 ( figures 3, 4 , 5, 6 ) associated with the same heat exchange unit 102 or with one of a plurality of said heat exchange units 102, respectively. This allows optimizing the shape of a "composite" total flow section while using a shape with possibly regular and even curvature, for example a circular or oval shape, of the annular outlet slot 108 and the guide surface 112, advantageous with reference to the uniformity of the driven air flow 113.
According to an embodiment, the conveying channel 106 comprises an annular portion (not necessarily circular) 120 forming the annular outlet slot 108, a fan seat 121 accommodating (at least a part of) the driving air fan 109, and a linear portion 122 (curved or straight) connected between the fan seat 121 and the annular portion 120 ( figures 7 , 8).
According to a further embodiment, the conveying channel 106 comprises a multiple (e.g., double) annular portion (not necessarily circular) 120, 120 forming the multiple annular outlet slots 108, 108' (e.g., double), a fan seat 121 accommodating (at least a part of) the driving air fan 109, and a single linear portion 120 (curved or straight) connected between the fan seat 121 and the multiple, e.g. double, annular portions 120, 120' ( figure 6 ).
According to a further embodiment, the conveying channel 106 comprises a multiple (e.g., double) annular portion (not necessarily circular) 120, 120' forming multiple, e.g., double, annular outlet slots 108, 108', a plurality of, e.g., two, distinct fan seats 121, 121' each accommodating (at least a part of) one of a plurality of (e.g., two) driving air fans 109, 109' and a plurality of, e.g., two, distinct linear portions 120, 120' (curved or straight), each connected between one of the fan seats 121, 121' and one of the multiple annular portions 120, 120'), respectively ( figure 5 ).
The different configurations of the conveying channel 106 allow optimized use of the spaces available inside the housing 117 of the heat exchanger 100 or of the heat pump 1 to which it is integrated.
According to an embodiment, the annular outlet slot 108 is arranged (only) upstream of the heat exchange unit 102, seen in the direction of the driven air flow 113.
According to an alternative embodiment, the annular outlet slot 108 is arranged (only) downstream of the heat exchange unit 102, seen in the direction of the driven air flow 113.
According to a still further embodiment, a first outlet slot of the one or more annular outlet slots 108 of the one or more air conveyors 105 is arranged upstream of the heat exchange unit 102, and a second slot of the one or more annular outlet slots 108 of the one or more air conveyors 105 is arranged downstream of the heat exchange unit 102, seen in a driven air flow direction 113. This allows obtaining a very high flow rate.
According to an embodiment which is not preferred but still falls within the scope of the invention, in the complete absence of the guide surface 112, the driven air flow 113 is generated due to the ejector effect, shown in figure 20 .
According to an embodiment which is not preferred but still falls within the scope of the invention, in the presence of a guide surface 112 with a straight section in the direction of the driving air flow 110, the driven air flow 113 is generated by the Coand
effect in combination with the ejector effect, shown in figure 21 .
According to a further, preferred, embodiment, in the presence of a guide surface 112 with a convex section gradually diverging in the direction of the driving air flow 110, the driven air flow 113 is generated by an amplified Coand
effect in combination with the ejector effect, shown in figure 22 .
The choice and definition of the precise shape of the guide surface 112 takes place in a known way, through numerical experimentation (simulation) and practical experimentation (testing), by applying aerodynamic design criteria of the wings of airplanes known per se. Therefore the method of designing the guide surface 112 is not the subject matter of the invention.
According to an embodiment, the air conveyor 105 comprises a heating device 123, for example an electric resistance, for example arranged upstream of or at the annular outlet slot 108, in order to be able to free the air annular outlet slot 108 and/or the guide surface 112 from deposits of ice or frost.
This is particularly advantageous in external units of heat pumps 1, with the air conveyor 104 placed downstream of the heat exchange unit 102, when defrosting the heat exchange unit 102 during winter operation. In fact, the moisture from the defrosting of the heat exchange unit 102 could otherwise deposit and freeze at the outlet slot 108 and/or the guide surface 112.
According to an embodiment, the inlet opening 107 can be in communication with an opening formed in the support structure 101 and/or in the outer housing 117.
According to an embodiment, the heat exchanger 100 either lacks a protective grille at the driven air flow 113 or forms a protective grille 124 with gaps being wider than a human finger.
Description of embodiments of the heat pump 1
According to an embodiment ( figure 18 ) a heat pump 1 comprises:

a circuit 2 for circulating a refrigerant fluid,
a first heat exchanger 3 placed in the circuit 2 and forming an evaporator 4,
a compressor 5 placed in the circuit 2 downstream of the first heat exchanger 3,
a second heat exchanger 6 placed in the circuit 2 downstream of the compressor 5 and forming a condenser 7,
an expansion device 8 placed in the circuit 2 downstream of the second heat exchanger 6,
an electronic control system 9 controlling the compressor 5, the expansion device 8, the first heat exchanger 3, and the second heat exchanger 6,

the compressor 5 is operable to suck in the refrigerant fluid in the gaseous phase and at low pressure from the evaporator 4, compress the refrigerant fluid, and push it into the condenser 7,
in the condenser 7, the compressed refrigerant fluid releases heat and condenses at high pressure,
after leaving the condenser 7, the refrigerant fluid passes through the expansion device 8 which depressurizes it,
the refrigerant fluid depressurized by the expansion device 8 enters into the evaporator 4 where it absorbs heat and evaporates at low pressure, before being sucked in and compressed again by the compressor 5,

heat exchanger

According to an embodiment, the heat pump 1 comprises an external unit 14 intended to be positioned outdoors, an internal unit 15 intended to be positioned inside a building and connected to a user/application 35, for example a heating/cooling system with a primary water circuit 16.
Preferably, the first heat exchanger 3 is a heat exchanger 100 according to the invention.
Preferably, the second heat exchanger 6 is a heat exchanger 100 according to the invention.
The external unit 14 comprises (inside a housing which can coincide with the external housing 117 of the heat exchanger 100):

the first heat exchanger 3 provided with an external air temperature sensor 18 and a refrigerant fluid temperature sensor 19,
the compressor 5 with a temperature sensor 20 for the refrigerant fluid on the suction side of the compressor 5, and with a temperature sensor 21 for the refrigerant fluid on the delivery side of the compressor 5,
a refrigerant fluid storage vessel 13 arranged on the suction side of the compressor 5,
a high pressure switch 22 arranged on the delivery side of the compressor 5,
the switching/reversing valve 12,
(connection attachment) tubes 23 of circuit 2,
the expansion device 8 with one or more electric expansion valves,
a refrigerant temperature sensor 24 placed in the circuit 2 between the expansion device 8 and the second heat exchanger 6.

The internal unit 15 comprises (inside a housing):

the second heat exchanger 6 which exchanges heat between the circuit 2 of the refrigerant fluid and the primary water circuit 16,
a water pump 25 in the primary water circuit 16 upstream of the second heat exchanger 6,
a flow rate sensor (flowmeter) 26, e.g., on the inlet side of the water pump 25,
a water return temperature sensor 27, e.g., on the inlet side of the water pump 25,
an expansion vessel 28 of the water connected to the primary water circuit 16, e.g., on the inlet side of the water pump 25,
a water filter 29 connected to the primary water circuit 16, e.g., upstream of the water pump 25 and/or upstream of the water expansion vessel 28,
a water delivery temperature sensor 30 (LWT = Leaving Water Temperature) at the outlet of the second heat exchanger 6,
a backup electric heater 31 connected in the primary water circuit 16, preferably downstream of the second heat exchanger 6, to an associated temperature sensor 32, for the water at the outlet of the backup electric heater 31, and
(connection attachments of) tubes 33 of circuit 2, and
(connection attachments of) tubes 34 of the primary water circuit.

The user/application 35 comprises a part of the primary water circuit 16 and a water vessel 36 and/or a plurality of heaters or radiators 36 for heating and cooling.
According to an embodiment, the external unit 14 of the heat pump 1 comprises an external housing, which coincides with the external housing 117 of the heat exchanger 100, and an internal separation partition 10, which separates a heat exchange compartment 11 from a compressor compartment 17, where:

the heat exchange compartment 11 accommodates the heat exchange unit 102, and
the compressor compartment 17 accommodates the compressor 5.

annular outlet slot

guide surface

heat exchange compartment

According to an embodiment, the entire air conveyor 105 is positioned in the heat exchange compartment 11 ( figures 8 , 13 , 14, 16 ). This allows utilizing spaces, for example in corners, currently unoccupied, in order to generate the air flow.
According to an alternative embodiment, the conveying channel 106 extends from the compressor compartment 17 into the heat exchange compartment 11 and the driving air fan 109, 109' is positioned in the compressor compartment 17 ( figures 9 , 11 , 12 , 15, 17 ). This allows utilizing the entire heat exchange compartment 11, even in the extension thereof in the direction of the air flow, for the heat exchange function and utilizing currently unused spaces of the compressor compartment 17 to generate the driving air flow 110.
According to an embodiment, the inlet opening 107 of the air conveyor 105 can be in communication with the compressor 5 for cooling the compressor 5.
According to an embodiment, the compressor compartment 17 is laterally near the heat exchange compartment 11 ( figures 8 , 11 , 12, 13 ).
According to an embodiment, the compressor compartment 17 is positioned below the heat exchange compartment 11 ( figures 14, 15).
According to an embodiment, the compressor compartment 17 is positioned above the heat exchange compartment 11 ( figures 16, 17).
According to an embodiment, the driven air flow 113 is substantially vertical, preferably upwards ( figures 9 , 11), or less preferably downwards.
According to an embodiment, the driven air flow 113 is substantially horizontal ( figure 8 ).
According to an embodiment, the compressor compartment 17 also accommodates the temperature sensor 20 for the refrigerant fluid on the suction side of the compressor 5, and the temperature sensor 21 for the refrigerant fluid on the delivery side of the compressor 5, the storage vessel 13 for refrigerant fluid arranged on the suction side of the compressor 5, the switching/reversing valve 12, the expansion device 8, and the refrigerant temperature sensor 24 located in the circuit 2 between the expansion device 8 and the second heat exchanger 6.

List of reference numerals in the figures

heat pump 1
circuit 2
first heat exchanger 3
evaporator 4
a compressor 5
second heat exchanger 6
condenser 7,
expansion device 8
electronic control system 9
internal separation partition 10
heat exchange compartment 11
switching/reversing valve 12
storage vessel 13
external unit 14
internal unit 15
primary water circuit 16
compressor compartment 17
external air temperature sensor 18
temperature sensor 19 for the refrigerant fluid in the first heat exchanger,
temperature sensor 20 for the refrigerant fluid on the suction side of the compressor 5
temperature sensor 21 for the refrigerant fluid on the delivery side of the compressor 5
high pressure switch 22
(connection attachments of) tubes 23 of the refrigerant circuit 2
refrigerant temperature sensor 24
water pump 25
water flow rate sensor 26
water temperature sensor 27
water expansion vessel 28
water filter 29
water delivery temperature sensor 30
backup electric heater 31
temperature sensor 32 for the water at the outlet of the electric heater (connection attachments of) tubes 33 of the refrigerant circuit 2 (connection attachments of the) tubes 34 of the primary water circuit user 35
water vessels/radiators 36
heat exchanger 100
support structure 101
heat exchange unit 102
fluid channel system 103
air channel system 104
air conveyor 105
conveying channel 106
inlet opening 107
outlet slot 108
driving air fan 109, 109'
driving air flow 110
driving flow direction 111
guide surface 112
driven air flow 113
driven flow direction 114
tubular closed-loop structure 115
peripheral edge portion 116
external housing 117
air outlet opening 118 of the housing
conveyor plane 119
annular portion 120, 120' of the conveying channel
fan seat 121, 121'
linear portion 122, 122'
heating device 123
protective grille 124

Claims

A heat pump (1) comprising:
- a circuit (2) for circulating a refrigerant fluid,

- a first heat exchanger (3) placed in the circuit (2) and forming an evaporator (4),

- a compressor (5) placed in the circuit (2) downstream of the first heat exchanger (3),

- a second heat exchanger (6) placed in the circuit (2) downstream of the compressor (5) and forming a condenser (7),

- an expansion device (8) placed in the circuit (2) downstream of the second heat exchanger (6),

- an electronic control system (9) controlling the compressor (5), the expansion device (8), the first heat exchanger (3), and the second heat exchanger (6),
wherein:
- the compressor (5) is operable to suck the refrigerant fluid in the gaseous phase and at low pressure from the evaporator (4), compress the refrigerant fluid, and push it into the condenser (7),

- in the condenser (7), the compressed refrigerant fluid releases heat and condenses at high pressure,

- after leaving the condenser (7), the refrigerant fluid passes through the expansion device (8) which depressurizes it,

- the refrigerant fluid depressurized by the expansion device (8) enters in the evaporator (4) where it absorbs heat and evaporates at low pressure, before being sucked and compressed again by the compressor (5),

wherein the heat pump (1) comprises an external unit (14) intended to be positioned in an external environment, an internal unit (15) intended to be positioned inside a building,

wherein at least one of the first (3) and second (4) heat exchangers is a heat exchanger (100) integrated in the external unit (14),

wherein said heat exchanger (100) integrated in the external unit (14) comprises:
- a support structure (101),

- a heat exchange unit (102) connected to the support structure (101) and having a fluid channel system (103) and an air channel system (104) in heat exchange communication with the fluid channel system (103),

- an air conveyor (105) connected to the support structure (101) and operable to convey an air flow through the air channel system (104) of the heat exchange unit (102), wherein the air conveyor (105) comprises:

- a tubular conveying channel (106) extending from an inlet opening (107) to an annular outlet slot (108),

- a driving air fan (109) placed in the conveying channel (106) and operable to suck a driving air flow (110) through the inlet opening (107) into the conveying channel (106) and expel the driving air flow (110) from the conveying channel (106), through the annular outlet slot (108), in the form of an annular air blade in a driving flow direction (111),

so as to generate an aerodynamic depression which sucks a driven air flow (113) with a higher flow rate than the flow rate of the driving air flow (110), in a driven flow direction (114),

wherein the outlet slot (108) is arranged at the heat exchange unit (102), so that at least the driven air flow (113) crosses the air channel system (104),

wherein the driving air fan (109) is arranged outside and at a distance from the driven air flow (113) and the heat exchanger (100) has no impellers with blades at the driven air flow (113).
A heat pump (1) according to claim 1, wherein said heat exchanger (100) comprises an annular guide surface (112) with convex continuous curvature, formed downstream of the annular outlet slot (108) in the direction of the driving air flow (111) and along the entire annular extension of the annular outlet slot (108), so as to generate a depression also due to the Coand
effect, which sucks the driven air flow (113).
A heat pump (1) according to claim 2, wherein the annular outlet slot (108) and the guide surface (112) are formed together in a single tubular closed-loop structure (115) mounted to the support structure (101).
A heat pump (1) according to claim 2 or 3, wherein the guide surface (112) is formed by - or forms - a peripheral edge (116) of an external housing (117) of the heat exchanger (100) delimiting an air outlet opening (118) of the external housing (117).
A heat pump (1) according to one of the preceding claims, wherein the annular outlet slot (108) and/or the tubular closed-loop structure (115) has a circular or oval shape or polygonal shape with rounded edges.
A heat pump (1) according to one of the preceding claims, wherein the annular outlet slot (108) and/or the tubular closed-loop structure (115) extend in a single conveyor plane (119) orthogonal to the driven flow direction (114).
A heat pump (1) according to one of the preceding claims, wherein the air conveyor (105) comprises two or more of said annular outlet slots (108) associated with the same heat exchange unit (102) or with one of a plurality of said heat exchange units (102), respectively.
A heat pump (1) according to one of the preceding claims, wherein the conveying channel (106) comprises an annular portion (120) forming the annular outlet slot (108), a fan seat (121) accommodating at least a part of the driving air fan (109), and a linear portion (122) connected between the fan seat (121) and the annular portion (120).
A heat pump (1) according to one of the preceding claims, wherein the conveying channel (106) comprises a multiple or double annular portion (120, 120') forming multiple or double annular outlet slots (108, 108'), a fan seat (121) accommodating at least a part of the driving air fan (109), and a single linear portion (120) connected between the fan seat (121) and the multiple or double annular portions (120, 120').
A heat pump (1) according to one of claims 1 to 8, wherein the conveying channel (106) comprises a multiple annular portion (120, 120') forming multiple annular outlet slots (108, 108'), a plurality of distinct fan seats (121, 121') each accommodating at least a part of one of a plurality of driving air fans (109, 109') and a plurality of distinct linear portions (120, 120'), respectively, each connected between one of the fan seats (121, 121') and one of the annular portions (120, 120'), respectively.
A heat pump (1) according to any one of the preceding claims, wherein the annular outlet slot (108) is arranged upstream of the heat exchange unit (102), seen in the driven flow direction (114), or wherein the annular outlet slot (108) is arranged downstream of the heat exchange unit (102), seen in the driven flow direction (114).
A heat pump (1) according to any one of the preceding claims, wherein the air conveyor (105) comprises a heating device (123) configured to defrost the annular outlet slot (108).
A heat pump (1) according to any one of the preceding claims, wherein said heat exchanger (100) has no protective grille at the driven air flow (113).
A heat pump (1) according to any one of the preceding claims, wherein the external unit (14) comprises an external housing, which coincides with an external housing (117) of the heat exchanger (100), and an internal separation partition (10), which separates a heat exchange compartment (11) containing the heat exchange unit (102) from the compressor compartment (17) housing the compressor (5),
wherein the annular outlet slot (108) is positioned at the heat exchange compartment (11).
A heat pump (1) according to claim 14, wherein the entire air conveyor (105) is positioned in the heat exchange compartment (1 1),or
wherein the conveying channel (106) extends from the compressor compartment (17) into the heat exchange compartment (11) and the driving air fan (109, 109') is positioned in the compressor compartment (17).
A heat pump (1) according to any one of the preceding claims, wherein the inlet opening (107) of the air conveyor (105) is or can be switched, in communication with the compressor (5) for at least temporarily cooling the compressor (5) and at least temporarily heating the driving air flow (110) upstream of the annular outlet slot (108).