WO2020178645A1

WO2020178645A1 - Method of humidification of the air flowing in the system and device for humidification of the air stream

Info

Publication number: WO2020178645A1
Application number: PCT/IB2020/051056
Authority: WO
Inventors: Marek Prymon
Original assignee: Thessla Green Sp. Z O.O.
Priority date: 2019-03-04
Filing date: 2020-02-11
Publication date: 2020-09-10
Also published as: WO2020178645A8; PL241124B1; PL429142A1

Abstract

A method of humidification of air flowing in the system, characterized in that part of the air stream flowing through the duct is routed as a result of the pressure difference caused by a damming element or a conduit placed for this purpose in the duct and directed to the humidification device, where the water content in this part of air is increased; after which this humidified air stream is again introduced into the duct, where it is mixed with the remaining part of the air stream flowing through the duct and thus the humidity of the air flowing through the duct is increased. A device for humidification of air flowing in the system, equipped with components for generating water vapour or water mist and for introducing water vapour or water mist into the stream of air flowing in the system, as well as a system for controlling and replenishing water, characterized in that within the ducts of a ventilation or air-conditioning installation a humidity distributor (1) is installed, containing a damming element, preferably in the form of a Venturi tube, constituting a section of the restrictor (12) of the humidity distributor (1), constituting a uniform part consisting of, on the side of the incoming stream; the distributor inlet port (14), confuser inlet section (10), distributor confuser section (11), restrictor section (12), diffuser section (13), and distributor outlet port (15), whereas the ports (14) and (15) are connected to the system (38), through which a stream of air to be humidified flows. The humidity distributor (1) forces some air to flow through the bypass channel or air moisturize it and then mix it with the remaining air.

Description

Method of humidification of the air flowing in the system and device for humidification of the air stream

The subject of the invention is the method of humidification of air flowing in ventilation or air conditioning systems, with ducts of any shape.

The invention also applies to the device for the humidification of the air stream flowing in ventilation or air conditioning systems by increasing the relative humidity of the air stream, using components generating water vapour or water mist and for introducing water vapour or water mist into the air stream flowing in the system, as well as control and water replenishment systems in components generating water vapour or water mist.

Relative air humidity affects both the comfort of room users and the correctness of processes in industrial buildings, e.g. production or storage facilities. Depending on the purpose of the room and its temperature, the relative humidity should be between 40 ÷ 65%. Humidity is the water vapour content of the air. The maximum humidity, i.e. the maximum amount of water vapour contained in a certain amount of air is strongly related to the air temperature. The higher the air temperature, the more water vapour can be in it. Exceeding the maximum humidity (e.g. as a result of lowering the air temperature) causes condensation of water vapour.

In air humidification devices, which are used in air conditioning systems, the process of air humidification is carried out mainly in two ways, namely by means of water or water vapour. In both cases, humidification consists of dispersing water or water vapour in chambers or ducts, directly into the flow of air.

In air conditioning systems, the air is humidified by means of water vapour or water spray (mist). Water or water vapour is added to air centrally, using the humidification section (chamber) in the air conditioning unit, or through a duct device mounted downstream of the unit.

Water vapour humidification systems are most often used in air conditioning and ventilation, these systems are mainly used in the systems of hotels and office buildings. Recently, there is a growing demand for air humidification also in systems operating in single-family houses. Air humidification consists in supplying the previously generated water vapour to the ducts of ventilation and air conditioning systems by means of water vapour lances or supplying water to heated vapour lances, where it is electrically heated to boiling point and thus evaporated. These devices are qualified as duct humidifiers.

A German utility model description number DE 20200900600B reveals a device for humidification of an air stream flowing in a system duct. The basic version of the device is a humidity generator placed in a humidifier unit, which consists of a front part onto which a stream of air pumped in the system is directed. The front part has a conical shape to facilitate airflow around the humidifier unit. The next part of the humidifier unit is the middle part where the humidity generator is located and the rear part in the form of a hemisphere. The humidity generator in the form of a water vapour generator, which is divided into two chambers; the lower one is separated with a sealed wall from the upper one. The lower chamber contains oil and the electric heater submerged in it. The heated oil transfers the heat to the upper chamber which is filled with water. The water converted into water vapour is extracted from the humidification unit with a steam lance and is entrained by a high velocity air stream through the damming element of the humidification unit. The steam-humidified air flow is mixed with the flow that flows around the humidification unit in the lower and side parts not in contact with the steam lance which introduces humidity generated in the humidity generator. In another embodiment of the device for humidification of the air stream flowing in the installation duct, the humidity generator adheres to the outside of the duct housing, and the humidity in the form of steam is introduced into the duct with the steam lance.

The air humidifier according to patent EP 2950009 has a boiler heated by a heating element for the liquid that is evaporated and has a steam valve through which steam can be discharged from the boiler to the space where the air requiring humidification is located. In the area below the normal level of the evaporated liquid when the boiler in operation is filled with the liquid, the boiler is connected with a vertical pipe which contains a device for determining the liquid filling level in the form of a float switch. The height and diameter of the vertical pipe are so dimensioned that the pipe can take the volume displaced from the boiler, depending on the diameter of the boiler and the difference between the upper filling level and the lower filling level. The height and diameter of the vertical pipe are so dimensioned that static pressure can be generated to push out the steam produced in the boiler through the steam valve.

The method of control of the air humidification device with a boiler heated by the heating element to evaporate the liquid, which has a steam valve through which the steam can be discharged from the boiler to the space to be humidified and equipped with a device to determine the level of liquid filling, including the following stages:

- closing the steam valve when the liquid in the boiler reaches at least the set upper filling level,

- switching on the heating element and heating, resulting in steam pressure that displaces the liquid from the boiler to the vertical pipe,

- switching off the heating element as soon as the liquid level in the boiler falls below the preset lower filling level,

- determining the time between switching the heating element on and off and determination of the load on the air humidifier from the ratio of the time between switching the heating element on and off. In the standby mode, which is activated by the demand signal, the steam valve is open. The heating element is not only affected by the base load, but also by the heating load, which corresponds to the demand signal.

The demand signal determines what humidity should be present in the humidified space. Using a suitable sensor in the room, humidity is detected and steam is supplied until the desired humidity is reached. It is only when the desired humidity is reached in the room that further demand signals are no longer sent. The device then goes into standby mode again.

Traditional steam humidifiers have a number of disadvantages and inconveniences

- they require the installation of a steam lance in a rectangular ventilation duct,

- steam lances must not be installed in round ducts because of the possibility of direct contact of air with the wall of the ventilation duct with humidity close to the saturation line, which would lead to condensation and water leakage from the duct. This limitation is an obstacle to installation in single-family house systems, where such ducts are mainly used,

- they introduce pure water vapour into the ventilation duct, which means that a long straight section of the duct is needed to absorb the water vapour due to the high risk of condensation of water from the air on the duct walls (high dew point temperature),

- along the section equal to the absorption distance the ventilation duct must be watertight,

- introduction of steam into the ventilation duct requires an appropriate specific airflow in the duct - limited from below and above,

- blockage of the steam pipe that supplies steam from the cylinder to the lance can lead to a dangerous high pressure in the steam cylinder where the water vapour is generated.

The aim of the invention is to develop a method of humidification of air flowing in ventilation or air conditioning systems, with any shape of system ducts and limiting the introduction of water vapour into the system ducts.

The aim of the invention is also to develop a new device for humidification of an air stream by increasing the relative humidity of the air stream using humidification means and implementing the method being the subject of the invention.

The essence of the method of humidification of the air flowing in the system is to increase the content of water vapour in the stream of air flowing in the system, according to the invention, is characterized by the fact that in the duct in which the air flows, a local pressure difference is caused by the action of the damming element which is a part of the humidity distributor mounted on the path of the air stream. By reducing the pressure in the restrictor section of the humidity distributor, which is an element that dams part of the air from the increased pressure zone (upstream of the convergent pipe section), is extracted outside of the system and directed to the steam or water mist generator. The air flowing through the bypass circuit is humidified in the generator. The air is humidified to a higher degree than the required level of humidity. The air humidified in the chamber of a humidity generator is introduced into the low-pressure zone of the humidity distributor (the restrictor of the convergent section), which is a damming element. The air humidified in the humidity generator to a humidity level higher than the set point is mixed, in the reduced pressure zone and the diffuser, with a stream of air flowing through the damming element. The air velocity in the restrictor section is relatively high (2-4 times higher than in the duct) so that dry air flows in the initial section of the diffuser in the wall layer and then the humidified air mixes quickly with the air flowing through the duct. Humidity is measured at the point where the level of humidity is checked and compared with the assumed value of humidity and if it is lower than the measured value the humidification process is started. In the case of a steam humidifier, the intensity of the water boiling process is regulated by the power of the electric heater placed in the tank of the humidity generator. The method of humidification of the air flowing in the system according to the invention consists in humidification of part of the air flowing in the system and mixing it with dry air, limiting, in the case of a steam humidifier, the direct introduction of water vapour into the system.

The humidity distributor is a homogeneous element consisting, from the incoming stream side, of the distributor inlet port, the confuser inlet section, the distributor confuser section, the restrictor section, diffuser section and the distributor outlet port. The distributor's inlet and outlet ports are connected to the system through which the humidified air stream flows. In the inlet section of the confuser there is a dry air outlet port from the distributor connected to the duct for air to be humidified, which is connected to the dry air inlet port to the humidity generator. In the restrictor section of the humidity distributor there is a humidified air inlet port to the distributor connected to the humidified air duct, which is connected to the humidified air outlet port from the humidity generator. The dry air inlet port to the humidity generator and the humidified air outlet port from the humidity generator are installed in the housing of the humidity generator in such a way that there is a water table of the humidity generator between their axes. The humidity generator is equipped with a resistance heater, a water temperature sensor, a water level sensor, a water supply system consisting of a set of water filters and an osmotic membrane and a booster pump as well as fittings and pipes of the hydraulic system. The air humidification device is also equipped with an air flow sensor mounted in the inlet section of the confuser, a humidity sensor in the ventilation duct downstream of the humidity distributor and a leading humidity sensor placed in the room or in the exhaust duct of the ventilation system. The sensors for water temperature, water level, air flow measurement, humidity in the ventilation duct downstream of the humidity distributor and the leading humidity sensor are connected to the controller with a microcontroller. The controller with a microcontroller controls the operation of the valve of the system filling the tank of the humidity generator and the pump emptying the humidity generator and is connected to the control panel. Preferably, the humidity distributor in the form of a Venturi tube has a confuser zone of length equal to LI, a restrictor section equal in length to L2 and a diffuser zone equal to L3. The diameter of the distributor's inlet port is D and is identical to the distributor's outlet port diameter and corresponds to the diameter of the system for air humidification. The diameter of the restrictor section is d and the d/D ratio is between 0.4 and 0.7. The Ll/D ratio is between 0.5 and 0.75. The L2/D relationship is between 0.5 and 0.7 and the L3/D relationship is between 0.4 and 0.7.

Preferably, the humidity distributor in the form of a Venturi tube, is a homogeneous element made of a material with appropriate mechanical strength and high insulation. The humidity distributor is made of permanently connected fittings made of foamed polypropylene with a wall thickness of 50 mm.

Preferably, the dry air outlet port from the distributor and the humidified air inlet port to the distributor are pipes with diameters ranging from 20.0 - 45.0 mm, made of stainless steel and permanently connected to the humidity distributor. Both ports have ends in the distributor which are right-angle triangles in cross-section, in which the hypotenuse line of intersection is inclined from the leg being the diameter of the tube at an angle of 60° to 80°. The dry air outlet port from the distributor is facing the incoming air and the humidified air inlet port to the humidity distributor is facing the outgoing air.

Preferably, the height of part of the dry air outlet port from the distributor located in the inlet section of the confuser is such that the axis of the cross-sectional projection of the port opening onto a plane perpendicular to the direction of air flow in the system is at the height of 1/5 of the diameter D. The height of part of the humidified air inlet port to the distributor located in the restrictor section is such that the axis of the cross-sectional projection of the port opening onto a plane perpendicular to the direction of air flow in the system is at the height of 3/4 of the diameter d.

Preferably, the humidity generator is equipped with a piezoelectric element generating water mist, which humidifies the air flowing over the water surface of the humidity generator between the dry air inlet port to the humidity generator and the humidified air outlet port from the humidity generator installed in the housing of the humidity generator.

The preferable effects of the invention are the possibility of making and easy, effective and safe installation of the humidification system in existing and operated ventilation systems which do not have the air humidification part. The method of air humidification which is the subject of the invention, uses a steam humidifier and at the same time reduces the stream of water vapour entering directly into the duct and thus shortens the section of the duct necessary to absorb the steam because the air is humidified by mixing the air flowing through the duct with the humidified stream. In addition, the method is not sensitive to pressure in the duct, as is the case with classic humidifiers, because the steam is transported to the duct by a Venturi and not the pressure in the steam generator. The use of this method of humidification in the adiabatic ultrasonic humidifier eliminates the need for an additional fan for water mist transport, simplifying the design and significantly increasing reliability. The method according to the invention and an embodiment of the device for humidification of a stream of air flowing in a system implementing the invention method is shown in a drawing where Fig. 1 shows a schematic representation of a part of the device for humidification of a stream of air flowing in a system implementing the invention method, Fig. 2 shows a schematic representation of a device for humidification of a stream of air flowing in a system, while Fig. 3 shows a schematic representation of a humidity distributor constituting the basic part of the device for humidification of a stream of air according to the invention.

In the embodiment, the air humidifier (1) consists of a steam generator (2), a hydraulic system supplying the steam generator with water, a tap water treatment system consisting of water filters (21) and an osmotic membrane (22), a steam generator drainage system, a control system (36) enclosed in one 552 x 635 x 180 mm housing and a humidity distributor (3) connected to the steam generator (2) with pipes (4) and (5), 38 mm in diameter. The steam generator is a cuboidal tank welded from stainless steel, with 20 mm thick high- temperature insulation on the outer surface. In the steam generator there is a resistance heater (16) with the power of 2200 W, a water temperature sensor (17), a float system to control the water level in the tank (18). The mains water treatment station consists of two filters - primary and secondary and an osmotic membrane. A 32 mm diameter drain port (32) to connect the humidification device to the sewerage system is connected to the 4-way valve (31), which includes a pipe from the pump emptying the steam generator (26), a reverse osmosis waste water pipe (28), an overflow pipe (29) downstream of the ball valve (30). The humidity distributor (3) is made of 50 mm thick foamed polypropylene fittings. The 80 cm long flexible duct (5) that connects the humidified air outlet port pipe from the steam generator (9) with the air intake port to the humidity distributor (7), is made of plastic and is insulated with a 10 mm thick material to minimize condensation of water from the humidified air on the walls of the duct and heat loss. The 85 cm long flexible duct (4) that connects the air outlet port from the humidity distributor (6) with the air inlet port (8) to the steam generator (2), is made of plastic and is insulated with 10 mm thick material to minimize heat loss. The control system consists of an electronic board with a microcontroller (36) which receives the input signals from the relative humidity sensor (34) downstream of the humidity distributor (3), from the relative humidity sensor in the room (35), from the float system (18), from the airflow sensor in the ventilation duct (33), from the water temperature sensor (17) in the steam generator (2) and sends output signals to control the heater (16), to switch on/off the emptying pump (27), to switch on/off the electromagnetic filling valve (24) and to the control panel (37).

The humidity distributor (3) is located in the air supply line of the ventilation system (38). In the restrictor of the distributor (12), there is a local static pressure drop and a dynamic pressure rise. Due to the resulting static pressure difference between the outlet port (6) from the dispenser and the inlet port (7) to the dispenser, part of the air flowing through the ventilation system (38) flows out of the dispenser with the outlet port (6) connected to the steam generator by a duct (4) with the steam generator (2) with the inlet port (8) to the steam generator, then it flows through the steam generator (2) and the duct (5) connecting the outlet port (9) of the steam generator with the inlet port (7) of the humidity distributor enters the restrictor section (12) and then the diffuser (13) of the humidity distributor (2). The bypass flow is proportional to the air flow in the system. The value of relative humidity to be maintained in the room is set from the control panel (37). If the set humidity value is lower than the value measured by the room humidity sensor (35), the controller (36) starts the humidification process. In the humidification mode, the steam generator (2) is filled with treated water and the air flowing over the water table is humidified. The water temperature in the steam generator (2) is controlled, depending on the need for humidification, in the range from the water temperature in the mains water supply to the boiling point, and the ventilation air flowing through the bypass system is humidified in the steam generator to a relative humidity level higher than the set value. The air humidified in the steam generator (2) to a humidity level higher than the setpoint is introduced into the humidity distributor (3) and mixed with dry ventilation air in the diffuser (13) of the humidity distributor (3).

The water level is replenished by opening the filling solenoid valve (24) based on the float signal (16).

The method of humidification of air flowing in the system and the device for humidification of air flowing in the system according to the invention enables easy, effective and safe installation of the humidification system in existing operating ventilation systems which do not have the air humidification part. The method of humidification and the device have been tested under operating conditions, confirming their advantages and usefulness in industrial application of the invention.

List of designations r

utor

ributor he generator

steam generator

nsor

e

m duct downstream of the distributor

Claims

Patent claims

1. A method of humidification of air flowing in the system, characterized in that part of the air stream flowing through the duct is routed as a result of the pressure difference caused by a damming element or a conduit placed for this purpose in the duct and directed to the humidification device, where the water content in this part of air is increased; after which this humidified air stream is again introduced into the duct, where it is mixed with the remaining part of the air stream flowing through the duct and thus the humidity of the air flowing through the duct is increased.

2. A device for humidification of air flowing in the system, equipped with components for generating water vapour or water mist and for introducing water vapour or water mist into the stream of air flowing in the system, as well as a system for controlling and replenishing water, characterized in that within the ducts of a ventilation or air- conditioning installation a humidity distributor (1) is installed, containing a damming element, preferably in the form of a Venturi tube, constituting a section of the restrictor (12) of the humidity distributor (1), constituting a uniform part consisting of, on the side of the incoming stream; the distributor inlet port (14), confuser inlet section (10), distributor confuser section (11), restrictor section (12), diffuser section (IB), and distributor outlet port (15), whereas the ports (14) and (15) are connected to the system (38), through which a stream of air to be humidified flows, while in the inlet section of the confuser (10) there is a dry air outlet port from the distributor (6) connected to the duct for air to be humidified (4), which is connected to the dry air inlet port pipe to the humidity generator (8) and in the restrictor section (12) there is a humidified air inlet port to the distributor (7) connected to the humidified air duct (5), which is connected to the humidified air outlet port from the humidity generator (9) and the ports (8) and (9) are mounted in the humidity generator housing (2) in such a way that between their axes there is a water table of the humidity generator (2), which is equipped with a resistance heater (16), water temperature sensor (17), water level sensor (18), a water supply system consisting of a water filtration device (21) and an osmotic diaphragm (22) and a pump to increase the water pressure in the event of a too low value in the water mains (23) and the fittings and pipes of the hydraulic system, as well as a sensor for measuring the air flow (33) mounted in the inlet section of the confuser (10), humidity sensor in the ventilation duct downstream of the distributor (34) and the leading humidity sensor (35) placed in the room or in the outlet duct of the ventilation system, where sensors (17), (18), (33), (34) and (35) are connected to the controller with a microcontroller (36), which controls the operation of the valve (24) and the pump (27) and is connected to the control panel (37).

3. The device, according to claim 2, is characterized in that the humidity distributor (1), preferably in the form of a Venturi tube, has a confuser zone (11) equal in length to LI, a restrictor section (12) of length equal to L2 and a diffuser zone (13) equal in length to L3, whereas the diameter of the distributor's inlet port (14) is D and is identical to the diameter of the distributor's outlet port (15) and corresponds to the diameter of the ventilation system (38) while the diameter of the restrictor section (12) is d and the d/D ratio is between 0.4 and 0.7, while the Ll/D ratio is between 0,5 and 0,75, the L2/D ratio is between 0,5 and 0,7 and the L3/D ratio is between 0,4 and 0,7.

4. The device, according to claim 2 characterized in that the humidity distributor (1), preferably in the form of a Venturi tube, is a part made of a material of appropriate mechanical strength and high insulation properties, preferably made of combined fittings of foamed polypropylene with a wall thickness of 50 mm.

5. The device, according to claim 2, characterized in that the dry air outlet port from the distributor (6) and the humidified air inlet port to the distributor (7) are pipes with internal diameters in the range of 20.0 - 45.0 mm, preferably made of stainless steel, permanently connected to the humidity distributor (3) and terminated, in cross- section with right-angle triangles in which the hypotenuse line of intersection is inclined from the leg being the pipe diameter and at an angle between 25° and 80°, with the opening aiming respectively in the direction opposite to the incoming airflow in the case of the outlet port (6) and in the direction matching that of the airflow in the case of the inlet port (7), increasing the differential pressure value obtained in the humidity distributor (3).

6. The device according to claim 2 characterized in that the height of the part of the dry air outlet port from the distributor (6) located in the inlet section of the confuser (10) is such, that the axis of the cross-sectional projection of the port opening (6) onto the plane perpendicular to the direction of air flow in the system (38) is at a height of 1/5 of diameter D and the height of the part of the humidified air intake port to the distributor (7) located in the restrictor section (12) is such that the axis of the cross- sectional projection of the port opening (7) onto the plane perpendicular to the direction of air flow in the system (38) is at a height of 3/4 of diameter d.