HVAC equipment and use of a three-way valve

Abstract

A HVAC device (1) is proposed, designed to transfer heat to or extract heat from a heat transfer fluid circulating in a heat transfer circuit (6). The HVAC device (1) has a housing (2) in which an expansion vessel (3) is arranged to compensate for volume fluctuations of the heat transfer fluid in the heat transfer circuit (6). A three-way valve (12) is connected to the heat transfer circuit (6) via a first port (14), to the expansion vessel (3) via a second port (15), and to a drain (13) via a third port (16). The three-way valve (12) can assume a first setting position (25) in which the first port (14) and second port (15) are connected and the third port (16) is closed, and a second setting position (26) in which the first port (14) is closed and the second port (15) and third port (16) are connected.Furthermore, the use of a three-way valve (12) is described. The invention enables significantly simplified maintenance and disassembly of an internal expansion vessel (3) of an HVAC device (1).

Description

[0001] The invention relates to an HVAC device and the use of a three-way valve.

[0002] The term "HVAC" stands for "Heating, Ventilation, and Air Conditioning," which refers to heating, ventilation, and air conditioning systems, such as heating systems. These systems can be connected to a heat transfer circuit, supplying or extracting heat from it. A heat transfer fluid, such as heating water or brine, circulates within this circuit, circulated by a pump. To compensate for temperature-related volume changes of the heat transfer fluid in the connected circuit, the HVAC system includes an expansion vessel. This expansion vessel is often integrated into the housing of an HVAC unit, also known as an internal expansion vessel.

[0003] Maintenance is necessary during the operation of an expansion vessel. In particular, the pressure of the gas volume contained within the expansion vessel must be regularly checked and adjusted. This requires measuring the pressure inside the expansion vessel, which usually necessitates opening an outlet. Opening the outlet of an internal expansion vessel is often complex, requiring the closure of a valve to the heat transfer circuit before opening the outlet. Furthermore, expansion vessels are subject to wear and tear, for example, due to age-related failure, and must be removed for replacement. This requires disconnecting the expansion vessel from the heat transfer circuit and then draining it. The necessary valves for this must be integrated into the HVAC unit and be accessible for installation work.The space required for valves and their accessibility contradicts the goal of a compact design. Furthermore, dismantling an internal expansion vessel is time-consuming, especially under the confined working conditions inside the HVAC unit's housing.

[0004] It is therefore an object of the invention to at least partially alleviate or solve the problems described with reference to the prior art. In particular, an HVAC unit and the use of a three-way valve are to be provided that enable the simple disassembly of an internal expansion vessel from an HVAC unit. Sources of error during disassembly work are also to be eliminated. Last but not least, the invention is intended to enable a compact design of the HVAC unit.

[0005] These problems are solved by the features of the independent claims. Further advantageous embodiments of the solution proposed here are specified in the independent claims. It should be noted that the features listed in the dependent claims can be combined with one another in any technologically meaningful way and define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, which also presents further preferred embodiments of the invention.

[0006] This is achieved using an HVAC unit designed to transfer heat to or extract heat from a (liquid) heat transfer fluid circulating in a connected or already connected heat transfer circuit. The HVAC unit comprises a housing and an expansion vessel located within the housing to compensate for volume fluctuations of the heat transfer fluid in the heat transfer circuit. The expansion vessel is connected via a three-way valve with a first port that can be connected to or is connected to the heat transfer circuit, a second port that is connected to the expansion vessel, and a third port that is connected to or is connected to a drain. The three-way valve is configured to selectively open or close the system.Alternatively, a first setting position in which the first and second ports are fluid-conducting and open, and the third port is closed, or a second setting position in which the first port is closed and the second and third ports are fluid-conducting and open.

[0007] An HVAC system can be any type of HVAC system, for example, one designed to change the temperature and / or humidity of a building or of one or more rooms within a building. An HVAC system can be a device, a fixture, and / or a component, or a combination thereof, that can provide the user with a solution tailored to one or more of the following tasks: • Heating • Ventilation • Air conditioning (cooling) • Hot water preparation • Electricity production • Energy management.

[0008] The HVAC system can be configured for heating or cooling. For example, the HVAC system can include a heating appliance, such as a gas-fired boiler. This boiler can be configured to draw in a mass flow of combustion air using a conveying device, such as a fan. A mass flow of fuel gas, corresponding to a predetermined combustion air-to-air ratio, can be added to this combustion air via a gas valve. The resulting combustion mixture is then fed to a burner and combusted. The heat generated during combustion can be transferred via a heat exchanger to the heat transfer medium (heating water) circulating in the heat transfer circuit and thus supplied to consumers such as radiators or underfloor heating systems.

[0009] The HVAC system can also include a heat pump. The heat pump can be designed to extract heat from an ambient medium, such as ambient air, the ground, or groundwater, and make it available for use. For this purpose, the heat pump can include a refrigeration cycle. This cycle circulates a refrigerant that undergoes a phase change in a compressor and a condenser to transfer heat. To control the phase change, the refrigeration cycle can also include a compressor and an expansion valve. The heat pump can have an indoor unit located inside the building being served and an outdoor unit located outside the building. Alternatively, the heat pump can also be a so-called monobloc unit, consisting of only one HVAC device. The heat pump can also function as an air conditioner that operates a refrigeration cycle to cool a room or building.

[0010] The HVAC system can be a modulating system, adjusting its output, particularly continuously, to meet heating or cooling demands. Depending on the required output, a mechanical component, such as a fan in a heating unit, one or more fans in the outdoor unit of a heat pump for heat exchange with ambient air, or a compressor in the refrigeration circuit of a heat pump, is typically operated at different speeds. Operating at varying output levels can result in different operating states.

[0011] The HVAC unit includes, in particular, a (single) internal expansion vessel, preferably designed separately or specifically for this purpose. This vessel is thus integrated into the housing of the HVAC unit. In other words, the HVAC unit has exactly one housing, in which the expansion vessel is included or enclosed.

[0012] An expansion vessel, also known as an expansion tank or pressure equalization tank, is designed to accommodate the volume fluctuations of a fluid in a hydraulic system, such as a connected heat transfer circuit, caused by temperature variations between a minimum and maximum temperature. Without an expansion vessel, for example, in a heating circuit heated by a boiler, the expanding fluid would escape through a pressure relief valve and would need to be refilled. Without a pressure relief valve, the pressure in the pipes and lines of the heating circuit would rise to such an extent that damage to the pipes, lines, or other components of the heating circuit would be likely.

[0013] Preferably, a diaphragm expansion vessel is used, in which a flexible diaphragm, for example made of rubber, separates a liquid volume from a gas volume. Nitrogen or ambient air is frequently used as the gas. The flexible diaphragm allows the liquid volume to increase while simultaneously reducing the compressed gas volume. The pre-charge pressure of the diaphragm expansion vessel can be set by adjusting the pressure of the gas within the gas volume. This pre-charge pressure must be checked and adjusted regularly to ensure the proper functioning of the heat transfer circuit. For this purpose, expansion vessels usually have a gas valve through which gas volume can be added or removed. Furthermore, an expansion vessel typically has exactly one connection for linking to a heat transfer circuit.

[0014] To adjust the pre-charge pressure of the expansion vessel, the connection to the heat transfer circuit is usually used, and the resulting pressure is measured. For this, the expansion vessel must be disconnected from the heat transfer circuit and emptied. The pre-charge pressure can then be adjusted using a pressure gauge and the gas valve.

[0015] Furthermore, the flexible diaphragm is subject to wear and tear. Once it becomes brittle due to age and a connection exists between the gas and liquid volumes, the expansion vessel can no longer fulfill its function and must be replaced. For this, it must be disconnected from the heat transfer circuit, and then the liquid it contains (the heat transfer fluid) must be drained. Therefore, this solution is particularly suitable for expansion vessels that require more maintenance.

[0016] The HVAC device presented here can significantly simplify maintenance work on, or even the replacement of, an expansion vessel. The three-way valve simply needs to be moved from the first to the second position. The first position connects the heat transfer circuit to the expansion vessel and is therefore the setting for normal operation of the HVAC system. In the second position, the first port of the three-way valve, connecting to the heat transfer circuit, is closed, and the second port is connected to the third port, connecting the expansion vessel to the outlet. Therefore, the second position is suitable for maintenance work, such as adjusting the pressure of the gas volume, or for removing the expansion vessel.This makes it particularly advantageous to separate the expansion vessel from the heat transfer circuit and simultaneously connect the expansion vessel to an outlet with just one adjustment movement.

[0017] In this invention, an outlet represents a connection to a building drain. HVAC devices often already have such a connection, for example to allow condensate that occurs during operation to drain away.

[0018] The three-way valve can be any three-way valve that has at least two adjustment positions, wherein in a first adjustment position the first and second ports of the three-way valve are connected and the third port is closed, and in a second adjustment position in which the first port is closed and the second and third ports are connected.

[0019] According to one embodiment, the three-way valve can have a cylindrical valve body. The cylinder has a circular base. The first, second, and third ports are arranged on a surface of the cylinder. A valve insert rests against this surface and can be rotated on it to set a position. The first and second positions are thus assigned to a rotational position of the valve insert. The valve insert includes openings that can open the first, second, and / or third port at a predetermined rotational position of the valve insert. In particular, the first and second ports can have a nearly identical angle with the center of the circular base of the valve body as the second and third ports.The angle corresponds to the rotational movement required to move from the first setting position to the second setting position and vice versa. The angle can be, for example, 90 degrees.

[0020] According to one embodiment, the three-way valve can be arranged adjacent to a pressure relief valve of the (connected) heat transfer circuit. In particular, the three-way valve can be connected to the pressure relief valve. The pressure relief valve is designed to open the heat transfer circuit above a permissible system pressure in order to prevent damage to the heat transfer circuit.

[0021] According to one embodiment, the (connected) heat transfer circuit can include a supply and a return line, and the first connection of the three-way valve can be hydraulically connected to the return line.

[0022] In particular, the use of a three-way valve is proposed to improve the serviceability of an HVAC unit's internal expansion vessel in a connected heat transfer circuit. The three-way valve comprises a first port connected to a heat transfer circuit, a second port connected to an expansion vessel, and a third port connected to a drain. It can assume two adjustable positions: a first position connecting the first and second ports and closing the third port, and a second position closing the first port and connecting the second and third ports.

[0023] The details, features, and designs discussed in connection with the HVAC unit may also occur in a use proposed here, and vice versa. In this respect, the features relating to the heating unit can also be used to characterize its use, and vice versa.

[0024] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described. Where a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or some of the multiple components, but this is not mandatory.

[0025] This invention presents a heating device and a three-way valve application that at least partially solve the problems described with reference to the prior art. In particular, the heating device and its application significantly simplify maintenance work on an internal expansion vessel of an HVAC unit, including its disassembly and assembly. Furthermore, the invention can reduce the number of valves required within the HVAC system, thereby facilitating a more compact design.

[0026] Furthermore, the invention is very well suited for retrofitting existing heating appliances and can often be implemented by simply inserting a three-way valve with the above-mentioned properties into the integration of the expansion vessel.

[0027] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other components and findings from the present description. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1: an HVAC device suggested here, Fig. 2: a three-way valve, Fig. 3: the three-way valve in the first setting position, and Fig. 4: the three-way valve in the second setting position.

[0028] Fig. Figure 1 shows an exemplary and schematic HVAC unit 1. This unit comprises a heat generator 23, which is connected to a heat transfer circuit 6 and can transfer heat to the heat transfer circuit 6 via a heat exchanger. The heat transfer circuit 6 has a supply line 4 and a return line 5, through which consumers such as radiators or underfloor heating systems can be connected to the HVAC unit 1. The heat transfer medium circulates in the heat transfer circuit 6 in a circulation direction 24, driven by a circulation pump 11. A heat exchanger 9 is arranged between the supply line 4 and the return line 5. It is designed to transfer heat from the heat transfer circuit 6 to a volume flow of potable or service water, which can be supplied to the heat exchanger 9 via a cold water inlet 7 and withdrawn via a hot water outlet 8.The HVAC unit 1 can switch from heating to hot water operation via a motor-driven hot water valve 10, which is designed as a three-way valve. An expansion vessel 3 is also connected to the return line 5 of the heat transfer circuit 6 via a three-way valve 12. The three-way valve 12 has three ports: a first port 14 is connected to the return line 5, a second port 15 to the expansion vessel 3, and a third port 16 to a drain 13. The expansion vessel 3 includes a gas valve 27, which allows the pre-charge pressure of the expansion vessel 3 to be set by connecting a pressure measuring device. The HVAC unit 1 has a housing 2 in which all components of the HVAC unit 1 are arranged, including the expansion vessel 3 as an internal expansion vessel.

[0029] Fig. Figure 2 shows an example of the three-way valve 12, which is connected to the heat transfer circuit 6 via a pressure relief valve 17 at its first port 14. The three-way valve 12 has an adjusting device 18 with which an adjustment position of the three-way valve 12 can be set. The adjusting device 18 can be rotated to set an adjustment position.

[0030] Fig. Figure 3 shows a sectional view of the three-way valve 12. The three-way valve 12 has a cylindrical valve body 19, in the outer surface of which the first port 14, the second port 15, and the third port 16 are arranged. A valve insert 20 can perform a rotary movement 21 about the center point of the circle of the base of the cylindrical shape of the valve body 19, thereby setting an adjustment position. The valve insert 20 can be mechanically connected to the adjusting means 18, such that a rotation of the adjusting means 18 causes a rotary movement 21 of the valve insert 20. In the Fig. In position 3, the first setting 25 on the three-way valve 12 is set, whereby openings 22 of the valve insert 20 open and connect the first port 14 and the second port 15, while the third port 16 is closed. The first setting 25 is therefore suitable for the normal operation of the HVAC unit 1, since the expansion vessel 3 is connected to the heat transfer circuit 6 and the drain 13 is closed.

[0031] The Fig. Figure 4 shows the representation of the three-way valve 12. Fig.3, however, in the second setting position 26, the second port 15 and the third port 16, and thus the expansion vessel 3 with the drain 13, are connected via the openings 22 in the valve insert 20, and the first port 14 is closed. The second setting position 26 is therefore suitable for setting the pressure of a gas volume in the expansion vessel 3 or also for removing the expansion vessel 3 from the housing 2 of the HVAC device 1. Reference symbol list 1 HVAC unit 2 cases 3 Expansion vessel 4 preliminary run 5 Return 6 Heat transfer cycle 7 Cold water inlet 8 Hot water outlet 9 Heat exchangers for hot water supply 10 Hot water valve 11 Circulation pump 12 Three-way valve 13 Procedure 14 first connection 15 second connection 16 third connection 17 Pressure relief valve 18 Adjustment devices 19 valve bodies 20 valve insert 21 Rotational movement 22 Opening 23 heat generators 24 Direction of rotation 25 first setting position 26 second setting position 27 Gas valve

Claims

[1] HVAC device (1) configured to transfer heat to or extract heat from a heat transfer medium circulating in a heat transfer circuit (6), comprising a housing (2) in which an expansion vessel (3) is arranged to compensate for volume fluctuations of the heat transfer medium in the heat transfer circuit (6), and comprising a three-way valve (12) with a first port (14) connectable to the heat transfer circuit (6), a second port (15) connected to the expansion vessel (3), and a third port (16) connectable or executable to a drain (13), wherein the three-way valve (12) has a first setting position (25) in which the first port (14) and second port (15) are connected and open and the third port (16) is closed, and a second setting position (26),in which the first connection (14) is closed and the second connection (15) and third connection (16) are connected and open. [2] HVAC device (1) according to claim 1, wherein the expansion vessel (3) is a diaphragm expansion vessel. [3] HVAC device (1) according to any of the preceding claims, wherein the HVAC device (1) comprises a gas heater and / or a heat pump. [4] HVAC device (1) according to one of the preceding claims, wherein the three-way valve (12) has a cylindrical valve body (19) and first port (14), second port (15) and third port (16) are arranged in a cylindrical surface and a valve insert (20) rests against the cylindrical surface and is rotatable sliding on the cylindrical surface to set an adjustment position. [5] Device comprising at least one HVAC device (1) according to one of the preceding claims and a heat transfer circuit (6), wherein the three-way valve (12) is arranged adjacent to a pressure relief valve (17) of the heat transfer circuit (6). [6] Device comprising at least one HVAC device (1) according to one of the preceding claims and a heat transfer circuit (6), wherein the heat transfer circuit (6) has a supply (4) and a return (5) and the first port (14) of the three-way valve (12) is hydraulically connected to the return (5).

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