EP4350230A1

EP4350230A1 - An air duct for a heat pump system

Info

Publication number: EP4350230A1
Application number: EP22199450.2A
Authority: EP
Inventors: Florian ANTOINE; Jean-François BOEHM; Arnaud Bichler
Original assignee: BDR Thermea Group BV
Current assignee: BDR Thermea Group BV
Priority date: 2022-10-04
Filing date: 2022-10-04
Publication date: 2024-04-10

Abstract

Providing an assembly for heating water in a building, in particular a heat pump system, wherein the assembly comprises a frame, a refrigerant component compartment, and a fan. The fan expelling any refrigerant gas from the refrigerant component compartment in case of a leakage of said refrigerant gas.

Description

The invention relates to an assembly for heating water in a building, in particular a heat pump system, wherein the assembly comprises a frame, a refrigerant component compartment, and a fan. The fan expelling any refrigerant gas from the refrigerant component compartment in case of a leakage of said refrigerant gas.
Heating of water in buildings, such as heating water of a central heating system or heating of water for domestic use, may be accomplished by means of a heat pump system. Such a heat pump system may either be a ground source heat pump (GSHP) system or an air source heat pump (ASHP) system. In a GSHP system, calories are exchanged between the ground, or ground water, and a fluid, the fluid in particular being air or water. The calories in the ground may be extracted by capturing calories in a water table or by circulating a water-based circuit in the ground. In an ASHP system calories are exchanged between the air and a fluid, in particular air or water.
A heat pump system typically comprises at least one first heat exchanger for capturing calories from a first source, at least one second heat exchanger for transferring captured calories to a second destination fluid, and a refrigerant loop between both heat exchangers to transport the captured calories from the at least one first heat exchanger to the at least one second heat exchanger. The at least one first and second heat exchangers together with the refrigerant loop form, at least a part of, a heat exchanging circuit.
The heat exchange achieved can be used to cool or heat the desired medium. Among the most commonly used circuits for a heat pump, the medium to be heated can be a heating water circuit and/or a sanitary water circuit.
With the advent of flammable refrigerants, components are preferably grouped in refrigerant components (including refrigerant pipes including brazing) and non-refrigerant components (e.g. hydraulics and electronics) where both groups are preferably separated for safety reasons. Furthermore, while leakage of any of the refrigerant components, including refrigerant pipes and brazing, is prevented as much as possible, there will always remain a slight chance of refrigerant leakage. As the refrigerant under regular room temperature and pressure is in a gaseous phase, this will create a fairly dense gas cloud within the heat pump system. With all sorts of electrical components within the heat pump system and the refrigerant being flammable, there is a risk of ignition and explosion of the refrigerant. Any such risk has to be mitigated.
It is therefore desired that any leaked refrigerant is expelled out of, and away from, the heat pump system as much and fast as possible. By expelling the refrigerant out and away from the heat pump system, the refrigerant in gaseous form will be further away from any ignition source within the heat pump system. Also, when the refrigerant is expelled into a larger space, the gas can naturally expand and become less dense. As a result of the lower density, the risk of ignition and explosion of the refrigerant would be further reduced. When the heat pump system is installed inside a building, the refrigerant could thus be expelled within a larger room or when properly ducted even towards the outside of the building.
The object of the invention is obtained by an assembly for heating water in a building, in particular a heat pump system, wherein the assembly comprises a frame, a refrigerant component compartment mounted on the inside of the frame, and a fan mounted on an outer panel of the frame and in fluid connection with the refrigerant compartment, wherein the refrigerant component compartment comprises a casing. The frame is an outer frame of the assembly. The frame holds a plurality of heat pump components. In an operational state, the frame comprises multiple panels on the outside to protect all the components situated within the frame and prevents users from accessing the heat pump components. Within the frame, a refrigerant component compartment is mounted which groups all the refrigerant components such as, amongst others, one or more heat exchangers, a compressor, an expansion valve and refrigerant piping comprising a refrigerant. The refrigerant component compartment separates the refrigerant components from any of the other components situated within the frame, in particular to separate potentially leaked flammable refrigerants and prevent the flammable refrigerant from reaching any of the other components. The refrigerant component compartment comprises one or more casing elements on at least one side to prevent any physical access to the refrigerant components after installment of the components. The casing elements may also reduce the chance of any potentially leaked refrigerant to flow from within the refrigerant components compartment to any of the other components situated within the frame. The fan mounted on the outer panel of the frame is in fluid connection with the refrigerant component compartment, meaning there is an air passage from the refrigerant component compartment to the fan. This may be an opening on at least one side of the refrigerant component compartment to which the fan is installed, or which is ducted towards the fan. Preferably, the fan is a brushless motor exhaust fan to ensure there is no electrical wiring within the fan that could potentially be an ignition source for the leaked refrigerant that passes through the fan. The fan may be operated and spinning continuously. Alternatively, the fan is only operated when a leakage is detected by means of a leakage detector situated within the refrigerant component compartment or by means of a combination of temperature and pressure sensors to detect a temperature and pressure drop within the system in comparison to normal operation. As such, any leaked refrigerant can be expelled and removed from within the refrigerant component compartment due to the air flow created by the fan, either operated continuously or upon detection of a leakage, and the object of the invention is thus achieved.
In an embodiment, the fan comprises a fastening surface which, when mounted to the frame, is orientated generally parallel to and in contact with the outer panel of the frame. The fastening surface may be a structural part of the fan, for example a portion of the surface surrounding the fan blades.
In an embodiment, the fan is mounted to the outer panel using a fan bracket wherein the fan bracket comprises a fastening surface which, when mounted to the frame, is orientated generally parallel to and in contact with the outer panel of the frame. The fan bracket is a separate surface or bracket in which the fan can be inserted. While a fan could be attached directly to a panel of the frame without the use of a fan bracket, the fastening surface can be increased by extending the contact area between the fan and the panel of the frame through the use of the fan bracket. Thus the tightness between the fan and the panel of the frame is increased. When using a separate bracket, the bracket may be attached to the panel of the frame prior to inserting the fan into the bracket.. This allows the use of standardized fans while the fan bracket can accommodate any size or shape necessary to properly mount to the frame. Furthermore, the fan bracket may act as a guide between the refrigerant component compartment and the outer side of the assembly.
In an embodiment, the fastening surface abuts the outer panel of the frame by at least 1,5 mm. This ensures that the contact area between the fastening surface and the outer panel of the frame is further increased and thus the tightness between the fan and the outer panel of the frame is increased. As such, the increased tightness improves the air flow due to a reduction of drop pressure and proper ducting, resulting in the reduction of the required fan speed which helps the improvement of the acoustic performance of the product as a whole. Furthermore, when an air duct is attached to the fan bracket, the increased tightness improves the safety of the system by preventing the passage of stale air along the edges of the fan bracket and into the installation site, thus ensuring the air travels along the path defined by the air duct.
In an embodiment, a seal is positioned between the fastening surface and the outer panel of the frame and/or between the refrigerant component compartment and the air duct. The seal further increases the air tightness between the fan and the outer panel of the frame. The seal may be one single seal or comprised out of multiple individual seals.
In an embodiment, the seal is integrated with the refrigerant component compartment. By integrating the seal with the refrigerant component compartment, the seal ensures air tightness between the refrigerant component compartment and the fastening surface and thus improving air tightness as a whole. The seal may by any kind of seal suitable to create said air tightness..
In an embodiment, the fastening surface comprises at least two fixing points to fasten the fan to the outer panel of the frame. The fastening surface can, in principle, be fixed to the outer frame using glue. In time, however, glue could come loose due to influences of heat and humidity. Using at least two fixing points allows a fixing means to protrude the fixing points and allow the fan being securely fastened to the outer panel of the frame. The fixing means may be, for instance, screws, rivets, clips, housing, hook or a combination thereof. Alternatively, the fixing means may be two or more guides protruding on the outer side of the outer frame for sliding and guiding the fan or fan bracket using the guides into a correct position without the use of screws or the like. Preferably, the fastening surface comprises at least three fixing points for improved stability of the fastening. The fixing means are preferably accessible from the outer side of the assembly. By having the fixing means on the outer side, the fan may be replaced without the need of opening the assembly. In particular, the fixing means are accessible from the side of the outer panel opposite of the refrigerant component compartment, allowing the compartment to be sealed the other side of the panel without the seal preventing the fan from being replaced, cleaned or mounted to the outer panel.
In an embodiment, the at least two fixing points are removable fixing means such as screws, nuts or couplings. While the fan can be securely fastened using, for instance, rivets, the fan should preferably be reversibly fastened to the outer panel of the frame.
When the fan needs to be replaced due to failure, a removable fixing means allow for quick and easy replacement of the fan without the need of, for instance, drilling rivets or the like. The removable fixing means are preferably accessible from the outer side of the assembly. By having the removable fixing means on the outer side, the fan may be replaced without the need of opening the assembly. In particular, the removable fixing means are accessible from the side of the outer panel opposite of the refrigerant component compartment, allowing the compartment to be sealed the other side of the panel without the seal preventing the fan from being replaced, cleaned or mounted to the outer panel.
In an embodiment, the fan or fan bracket comprises at least one guide surface. By proving a guide surface to the fan or fan bracket, the guide surface may act like a flange that may allow, for instance, a tube to be placed over the flange. This allows for an air duct to be securely mounted over the guide surface and to the fan.
In an embodiment, the at least one guide surface extends by at least 8 mm. When a longer air duct would be mounted over the guide surface and to the fan, the guide surface preferably extends by at least 8 mm to securely mount such a longer air duct.
In an embodiment, the at least one guide surface has a cross-sectional area of at least 500 mm2. This allows for sufficient air flow to pass through the guide surface and also allows for an air duct to be mounted with a similar cross-sectional area.
In an embodiment, an air duct is mounted to the at least one guide surface. The air duct allows for any leaked refrigerant being directed away from the assembly, into the direction the air duct is extending. The air duct may, for instance, be extended towards the outside of the assembly, in particular to the outside of a building to direct the leaked refrigerant outside of the building. The air duct may be any tube, pipe or channel suitable to be used as an air duct. The air duct may, also, extend towards the inside of the assembly to meet with the refrigerant component compartment, thus allowing a connection of said compartment connecting to the part of the air duct, or a separate air duct, extending towards the outside of the assembly.
In an embodiment, the lowest point of the air duct is situated less than 200 mm in height in relation to a compressor situated within the refrigerant component compartment. This is the distance between the lowest point of the opening in the air duct and the plate on which the compressor rests. If the compressor leaks, leaked refrigerant can only buildup up to 200 mm in height starting from the base of the assembly. This prevents the refrigerant component compartment from filling with refrigerant as any leaked refrigerant will naturally flow towards the lowest point if the air duct. Furthermore, any kind of electronics, that could potentially be an ignition point, situated in the same compartment could then be positioned well above this area to prevent ignition of the leaked refrigerant.
In an embodiment, the air duct has a cross-sectional area of at least 500 mm2. This allows for sufficient air flow to pass through the air duct.
In the figures, the subject-matter of the invention is schematically shown, wherein identical or similarly acting elements are usually provided with the same reference signs.

Figure 1: shows a schematic representation of an assembly according to the present invention.
Figure 2: shows a schematic representation of a fan according to an embodiment of the present invention.
Figure 3: shows a schematic representation of an assembly according to an embodiment of the present invention.

With reference to Figure 1, an assembly 1 is shown comprising a frame 2, a refrigerant component compartment 3 further comprising a casing 4, and a fan 5 sitting within fan bracket 6. The fan bracket 6 contacts the refrigerant component compartment 3 by abutting to its casing 4. Furthermore, the fan 5 comprises a fastening surface 7 with fixing points 8a, 8b and a guiding surface 8. The assembly 1 as shown also comprises several heat pump components, including refrigerant components shown within the refrigerant component compartment 3.
Figure 2 shows the fan 5 of assembly 1 in an exploded view. The fan 5 as shown has a fan bracket 6 comprising fastening surface 7. The fastening surface 7 comprises two fixing points 8a, 8b and the fan bracket 6 further comprises a guiding surface 9.
In Figure 3, the same assembly 1 is shown as in Figure 1. However, now an air duct 10 is also shown mounted over the guiding surface 9.

Reference Signs

1: assembly
2: frame
3: refrigerant component compartment
4: refrigerant component compartment casing
5: fan
6: fan bracket
7: fastening surface
8a, 8b: fixing points
9: guiding surface
10: air duct

Claims

An assembly (1) for heating water in a building, in particular a heat pump system, wherein the assembly (1) comprises:
- a frame (2);

- a refrigerant component compartment (3) mounted on the inside of the frame; and

- a fan (5) mounted on an outer panel of the frame (2) and in fluid connection with the refrigerant compartment (3);
wherein the refrigerant component compartment (3) comprises a casing (4).
The assembly (1) according to claim 1, wherein the fan (5) comprises a fastening surface (7) which, when mounted to the frame (2), is orientated generally parallel to and in contact with the outer panel of the frame (2).
The assembly (1) according to claim 1, wherein the fan (5) is mounted to the outer panel using a fan bracket (6) wherein the fan bracket (6) comprises a fastening surface (7) which, when mounted to the frame (2), is orientated generally parallel to and in contact with the outer panel of the frame (2).
The assembly (1) according to claim 2 or 3, wherein the fastening surface (7) abuts the outer panel of the frame (2) by at least 1,5 mm.
The assembly (1) according to claim 4, wherein a seal is positioned between the fastening surface (7) and the outer panel of the frame (2).
The assembly (1) according to claim 5, wherein the seal is integrated with the refrigerant component compartment (3).
The assembly (1) according to any of the claims 2 to 6, wherein the fastening surface (7) comprises at least two fixing points (8a, 8b) to fasten the fan (5) to the outer panel of the frame (2).
The assembly (1) according to claim 7, wherein the at least two fixing points (8a, 8b) are removable fixing means such as screws, nuts or couplings.
The assembly (1) according to any of the preceding claims, wherein the fan (5) or fan bracket (6) comprises at least one guide surface (9).
The assembly (1) according to claim 9, wherein the at least one guide surface (9) extends by at least 8 mm.
The assembly (1) according to claim 9 or 10, wherein the at least one guide surface (9) has a cross-sectional of at least 500 mm2.
The assembly (1) according to any of the preceding claims, wherein an air duct (10) is mounted to the at least one guide surface (9).
The assembly (1) according to claim 12, wherein the lowest point of the air duct (10) is situated less than 200 mm in height in relation to a compressor situated within the refrigerant component compartment (3).
The assembly (1) according to claim 12 or 13, wherein the air duct (10) has a cross-sectional area of at least 500 mm2.