CN213270338U

CN213270338U - Centrifugal fan and heating, ventilating, air conditioning and refrigerating system

Info

Publication number: CN213270338U
Application number: CN202022157496.7U
Authority: CN
Inventors: 陈学锋; 王帮玉; 王庆浩; 曹德彬
Original assignee: Trane Air Conditioning Systems China Co Ltd; Trane International Inc
Current assignee: Trane Air Conditioning Systems China Co Ltd; Trane International Inc
Priority date: 2020-09-27
Filing date: 2020-09-27
Publication date: 2021-05-25
Anticipated expiration: 2030-09-27

Abstract

A centrifugal fan and a heating, ventilating, air conditioning and refrigerating system are disclosed. The centrifugal fan includes a volute having an inner surface and a curved inlet shroud. The volute defines an air outlet. The curved inlet shroud defines an air inlet. The air inlet has an inlet airflow cross-sectional area that is substantially perpendicular to an outlet airflow cross-sectional area of the air outlet. The centrifugal fan further includes an impeller mounted for rotation within the volute about an axis of rotation. The impeller has a plurality of fan blades. The plurality of fan blades have an outer surface. The centrifugal fan further comprises a light source. The inner surface of the volute and the outer surface of the plurality of fan blades include a photocatalyst layer. The light source is configured to emit light onto the photocatalyst layer.

Description

Centrifugal fan and heating, ventilating, air conditioning and refrigerating system

Technical Field

The present disclosure relates generally to centrifugal fans/blowers for heating, ventilation, air conditioning, and refrigeration (HVACR) systems. More particularly, the present disclosure relates to systems and methods for configuring and controlling centrifugal fan/blowers having photocatalytic oxidation (PCO) and/or ultraviolet germicidal irradiation techniques to improve the efficiency and efficacy of air one-time filtration and/or sterilization for HVACR systems.

Background

Centrifugal fans (or blowers) are widely used to circulate air in residential and commercial HVACR systems. Motor driven centrifugal fans having a volute or scroll fan housing are particularly widely used where the fan housing is mounted in a cabinet that also contains an HVACR system of heat transfer equipment (e.g., refrigerant fluid heat exchanger or furnace heat exchanger, etc.).

The world is currently experiencing a global epidemic. The owners and operators of buildings (business, industry and residential) face different challenges with respect to the spread of pathogens (bacteria, fungi, protozoa, worms, viruses and/or infectious proteins such as prions) such as more complex building and space designs, increased population and population density, increased mobility of people around the world and general growth of the interconnections between people around the world, and the technologies associated with accommodating these complexities and growth. Owners and operators of buildings are turning to the policies, regulations and operations of buildings and using technologies to reduce/kill pathogens and keep air clean. Further solutions to overcome these challenges may benefit public health and safety.

SUMMERY OF THE UTILITY MODEL

Owners and operators (businesses, industries, and residences) of buildings are able to control the air movement, temperature, humidity, and air cleaning technology of air conditioning within their buildings. The problem with today's pandemics is that the science surrounding best practices to minimize the number of infections that can occur in the occupied space is still unknown and under investigation. Some studies have shown that there may be a portion of a particular population that is predisposed to a higher infection rate and/or a higher disease susceptibility, such as disease severity for COVID-19.

The present disclosure relates generally to centrifugal fans/blowers for HVACR systems. More particularly, the present disclosure relates to systems and methods for configuring and controlling centrifugal fan/blowers having photocatalytic oxidation and/or ultraviolet germicidal irradiation techniques to improve the efficiency and efficacy of air one-time filtration and/or sterilization for HVACR systems.

Embodiments disclosed herein may be used, for example, to control air-conditioned air spaces and lighting, to reduce or kill pathogens or microbes, to reduce susceptibility of residents to microbial infections, to reduce the effects of disease from microbes, and/or to reduce the spread of pathogens or microbes. Embodiments disclosed herein may provide health improvement in the presence of microorganisms, particulate matter, and other airborne matter that may be harmful to human (or other animal or plant) health.

A centrifugal fan for an HVACR system is disclosed. The centrifugal fan includes a volute having an inner surface and a curved inlet shroud. The volute defines an air outlet. The curved inlet shroud defines an air inlet. The air inlet has an inlet airflow cross-sectional area that is perpendicular to an outlet airflow cross-sectional area of the air outlet. The centrifugal fan further comprises an impeller mounted for rotation within the volute about an axis of rotation. The impeller has a plurality of fan blades. The plurality of fan blades have an outer surface. The centrifugal fan further comprises a light source. The inner surface of the volute and the outer surface of the plurality of fan blades include a photocatalyst layer. The light source is configured to emit light onto the photocatalyst layer.

A method of configuring a centrifugal fan for an HVACR system is disclosed. The centrifugal fan includes a volute having an inner surface and a curved inlet shroud. The volute defines an air outlet. The curved inlet shroud defines an air inlet. The air inlet has an inlet airflow cross-sectional area that is perpendicular to an outlet airflow cross-sectional area of the air outlet. The centrifugal fan further comprises an impeller mounted for rotation within the volute about an axis of rotation. The impeller has a plurality of fan blades. The plurality of fan blades have an outer surface. The centrifugal fan further comprises a light source. The method includes coating or sintering a photocatalyst layer on an inner surface of a volute and an outer surface of a plurality of fan blades. The method also includes emitting light by a light source onto the photocatalyst layer.

Drawings

Reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration embodiments in which the systems and methods described in this specification may be practiced.

Fig. 1 is a schematic diagram of a refrigeration circuit that may be implemented in an HVACR system, according to an embodiment.

Fig. 2 is a perspective view, partially in section, of an air handling unit of an HVACR system with a centrifugal fan, according to an embodiment shown.

Fig. 3 is a perspective view of a return box of an HVACR system with a light source shown according to an embodiment.

Fig. 4 is a table showing particle sizes according to an example.

Fig. 5 is a side view schematic of a centrifugal fan of an HVACR system according to an embodiment.

Fig. 6 is a perspective view of a voluteless centrifugal fan of an HVACR system according to an embodiment.

Fig. 7 shows a simulation result of light intensities of two light sources in the centrifugal fan according to the embodiment.

Fig. 8 shows simulation results of time and light dose required to inactivate viruses in a centrifugal fan according to an embodiment.

Fig. 9 shows the test results of the formaldehyde purification test according to the example.

10A-15E are perspective views of a centrifugal fan having light source(s) according to some embodiments.

16A-16D are schematic illustrations of a photocatalyst layer disposed on a surface of a centrifugal fan, according to some embodiments.

Like reference numerals refer to like parts throughout.

Detailed Description

The following definitions apply throughout this disclosure. As defined herein, the term "photocatalyst" may refer to a material that absorbs light to bring it to a higher energy level and provides that energy to a reactive species to undergo a chemical reaction. It is understood that in catalytic photolysis, light is absorbed by adsorbed species. In photo-catalytic, the photocatalytic activity depends on the catalyst's ability to generate electron-hole pairs that generate free radicals (e.g., hydroxyl radicals: OH) that are capable of undergoing secondary reactions. It should be understood by discovery, for example, with titanium dioxide (TiO)₂) Water electrolysis is carried out, so that practical application becomes possible. It should be understood that photons have a certain energy. When irradiated to certain substances (e.g. including TiO)₂The semiconductor of (1), an electron of an atom, after absorbing a certain energy, will transit from the valence band to the conduction band. There will be positively charged holes, i.e., photo-generated electrons and photo-generated holes. The positively charged holes combine with water molecules in the air to generate hydroxyl radicals having oxidizing and decomposing capabilities, while the negative electrons combine with oxygen in the air to form active oxygen. Because these electrons and holes have strong reducing and oxidizing properties, respectively, they can cause substances on the semiconductor to undergo redox reactions (e.g., to reduce/kill pathogens), thereby converting light energy into chemical energy. These substances are called photocatalysts.

As defined herein, the term "ultraviolet light" or "UV" may refer to a form of electromagnetic radiation having a wavelength ranging from 10nm or about 10nm to 400nm or about 400 nm. As defined herein, the term "UVA" may refer to UV in the wavelength range from 315nm or about 315nm to 400nm or about 400nm, the term "UVB" may refer to UV in the wavelength range from 280nm or about 280nm to 315nm or about 315nm, and the term "UVC" may refer to UV in the wavelength range from 100nm or about 100nm to 280nm or about 280 nm.

Specific embodiments of the present disclosure are described herein with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure, which can be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. In the present description and in the drawings, the same reference numerals indicate elements that may perform the same, similar or equivalent functions.

In addition, the present disclosure may be described herein in terms of functional block components, code manifests, selectable options, page displays, and various processing steps. It should be appreciated that such functional blocks may be realized by any number of hardware and/or software components configured to perform the specified functions. For example, the present disclosure may employ various integrated circuit components, e.g., memory elements, processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices.

The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the examples given herein. For example, the steps recited in any method claims may be executed in any order and are not limited to the order presented in the claims. Moreover, no element is essential to the practice of the disclosure unless specifically described as "critical" or "essential" herein.

Fig. 1 is a schematic diagram of a refrigerant circuit 100 according to an embodiment. The refrigerant circuit 100 generally includes a compressor 120, a condenser 140, an expansion device 160, and an evaporator 180. An "expansion device" as described herein may also be referred to as an expander. In an embodiment, the expander may be an expansion valve, an expansion plate, an expansion vessel, an orifice, or the like, or other such type of expansion mechanism. It should be understood that the expander may be any suitable type of expander known in the art for expanding a working fluid to reduce the pressure and temperature of the working fluid. In one embodiment, the evaporator 180 may be a microchannel heat exchanger. The refrigerant circuit 100 is an example and may be modified to include additional components. For example, in an embodiment, the refrigerant circuit 100 may include other components such as, but not limited to, an economizer heat exchanger, one or more flow control devices, a receiver tank, a dryer, a suction liquid heat exchanger, and the like.

The refrigerant circuit 100 may generally be applied to various systems that control environmental conditions (e.g., temperature, humidity, air quality, etc.) in a space (often referred to as a conditioned space). Examples of such systems include, but are not limited to, HVACR systems, transport refrigeration systems, and the like. In an embodiment, the HVACR system may be a rooftop unit or a heat pump air conditioning unit.

The compressor 120, condenser 140, expansion device 160, and evaporator 180 are fluidly connected. In an embodiment, the refrigerant circuit 100 may be configured as a cooling system (e.g., an air conditioning system) capable of operating in a cooling mode. In an embodiment, the refrigerant circuit 100 may be configured as a heat pump system that can operate in both a cooling mode and a heating/defrost mode. A centrifugal fan (not shown, described later) may be provided to the heat exchanger such as the condenser 140 and/or the evaporator 180.

It is understood, for example, that in U.S. patent nos. 7,591,633; 7,186,080, respectively; 7,108,478, respectively; 5,570,996; 5,558,499, respectively; 3,627,440, respectively; 3,307,776, respectively; 3,217,976, respectively; 2,981,461, respectively; 2,951,630, respectively; 2,798,658, respectively; 2,727,680, respectively; 3,221,983, respectively; and 1,862,523, the entire disclosures of which are incorporated herein by reference.

The refrigerant circuit 100 may operate according to generally known principles. The refrigerant loop 100 may be configured to heat and/or cool a liquid process fluid (e.g., a heat transfer fluid or medium (e.g., a liquid such as, but not limited to, water, etc.)), in which case the refrigerant loop 100 may generally represent a liquid chiller system. The refrigerant circuit 100 may alternatively be configured to heat and/or cool a gaseous process fluid (e.g., a heat transfer medium or fluid (e.g., a gas such as, but not limited to, air, etc.), in which case the refrigerant circuit 100 may generally represent an air conditioner and/or a heat pump.

In operation, the compressor 120 compresses a working fluid (e.g., a heat transfer fluid (e.g., a refrigerant, etc.)) from a relatively low pressure gas to a relatively high pressure gas. The relatively high pressure gas, which is discharged from the compressor 120 and flows through the condenser 140, is also at a relatively high temperature. In accordance with generally known principles, the working fluid flows through the condenser 140 and rejects heat to a process fluid (e.g., water, air, etc.), thereby cooling the working fluid. The cooled working fluid, now in a liquid state, flows to the expansion device 160. The expansion device 160 reduces the pressure of the working fluid. Thus, a part of the working fluid is converted into a gaseous state. The working fluid, now in a mixed liquid and gaseous state, flows to the evaporator 180. The working fluid flows through the evaporator 180 and absorbs heat from the process fluid (e.g., a heat transfer medium such as water, air, etc.), heating the working fluid and converting it to a gaseous state. The gaseous working fluid is then returned to the compressor 120. The above process continues while the heat transfer circuit is operating, for example, in a cooling mode (e.g., when the compressor 120 is started).

Fig. 2 is a perspective view, partially in section, illustrating an air handling unit 200 (air handler) of an HVACR system having a centrifugal fan 250, according to an embodiment.

The unit 200 includes a housing 260. In one embodiment, the enclosure 260 may be a generally rectangular cabinet having a first end wall defining an air inlet opening 270 (to allow air to flow into the interior space of the enclosure 260) and a second end wall defining an air outlet opening (not shown to allow air to flow out of the enclosure 260 via the air outlet (overlapping the air outlet opening) of the centrifugal fan 250, see, e.g., 660 in fig. 5). In fig. 2, a side wall of the housing 260 is cut away, and an inner space of the housing 260 is shown.

Unit 200 also includes a primary filter 210 and a secondary filter 220. In one embodiment, primary filter 210 and secondary filter 220 may be one filter. It should be understood that primary filter 210 and/or secondary filter 220 may be a porous device configured to remove impurities or solid particles from an air stream passing through the device.

In one embodiment, the outer surface(s) (e.g., the entire surface facing the gas flow and/or the entire surface opposite the surface facing the gas flow) of secondary filter 220 (and/or primary filter 210) may be covered (or coated or sintered) with, for example, a photocatalyst layer (see fig. 16A-16D). A light source (not shown, see fig. 10A-15A) may be added to the housing 260 to emit light onto a photocatalyst layer disposed on the outer surface of the filter through which air passes. This embodiment provides a solution to achieve photocatalytic oxidation and/or ultraviolet germicidal irradiation on the surface of the filter(s). In this embodiment, more space is required in the housing 260 (e.g., for placement of the light source) (and thus, the length of the housing may need to be increased, or the light source may occupy space in other components within the housing 260), an air pressure drop may occur on the outer surface of the filter (e.g., due to the addition of a photocatalyst layer into the filter, thereby increasing resistance to air), and/or a sealed mounting may be required (e.g., for the light source to prevent UV light, such as UVC light, from leaking out of the housing 260). In this embodiment, the efficiency and efficacy of the one-time filtration and/or sterilization of air may be optimal, as for example the outer surface(s) of the filter may cover the entire airflow through the filter.

Unit 200 also includes components (e.g., coiled tubing) 230. In one embodiment, the assembly 230 may be an air conditioning evaporator coil disposed in the air flow path from the air inlet opening 270 to the air outlet opening of the housing 260 (also the air outlet of the blower 250). It should be understood that the assembly 230 may be of different types, as the working fluid may be, for example, a refrigerant, water, or the like. For example, when the working fluid is a refrigerant, the assembly 230 may be an evaporator coil for cooling, and/or may be a condenser coil for heating. For example, when the working fluid is water, the assembly 230 may be a pipe through which cooling water passes for cooling, and may be a pipe through which hot water passes for heating.

The unit 200 also includes a humidifier 240, the humidifier 240 being configured to add moisture to the air to prevent drying, which may cause inflammation in many parts of the human body, or to increase the humidity in the air.

The unit 200 also includes a blower (or blower) 250. In one embodiment, the fan 250 may be a centrifugal fan having an electric drive motor (not shown) to drive the fan 250 (e.g., to drive a shaft of the fan 250, see fig. 11A, to rotate an impeller of the fan 250). It will be appreciated that a centrifugal fan is a mechanical device for moving air or other gas in a direction at an angle (e.g. perpendicular) to the air entering from the inlet of the fan towards the outlet of the fan. Centrifugal fans typically include a ducted housing for directing the exhaust air in a particular direction or through a heat sink. Centrifugal fans can increase the speed and volume of the airflow by means of a rotating impeller.

Fig. 3 is a perspective view illustrating a return box 300 of an HVACR system having a light source 320 according to an embodiment. The case 300 includes a housing 310. In fig. 3, the inner space of the casing 310 is shown as seen from the return air outlet of the casing 310.

The light source 320 includes a lamp 322 and a controller 321. In one embodiment, the controller 321 may be a control gear and/or a ballast. The lamp 322 may be the light source described in fig. 10A-15A. In one embodiment, the lamp 322 is covered by a housing 323 (e.g., made of metal mesh, sponge, etc.) having a photocatalyst layer (see fig. 16A-16D). A lamp 322 may be illuminated on the housing. This embodiment provides a solution (e.g., photocatalytic oxidation and/or ultraviolet germicidal irradiation) similar to that described in detail with respect to centrifugal fan 250. In this embodiment, the light source 320 is inserted into the inner space of the housing, is easy to install, is low in cost, and has low resistance to air flow. In this embodiment, the efficacy and/or efficiency of the disposable filtering and/or sterilization of the air may not be optimal because the entire airflow that is passing through the enclosure 300 may not be covered/contacted by the solution (e.g., photocatalytic oxidation and/or ultraviolet germicidal irradiation) provided by the housing of the lamps 322 and the lamps 322.

Fig. 4 is a table 400 illustrating particle sizes according to an embodiment. As shown in fig. 4, the size of the virus ranges from 0.01 microns or about 0.01 microns to 0.05 microns or about 0.05 microns, and the size of the droplet core (droplet core) ranges from 0.5 microns or about 0.5 microns to 5 microns or about 5 microns. Many high risk inhalable particles range in size from 0.01 microns or about 0.01 microns to 10 microns or about 10 microns. Particles having a size of 50 microns or more are typically visible to the naked eye. It is to be understood that computational fluid dynamics analysis results may demonstrate the efficiency of removing high risk inhalable particles (e.g., ranging in size from 0.01 microns or about 0.01 microns to 10 microns or about 10 microns). The difference in efficiency between the centrifugal and vortex air flows may indicate that the centrifugal air flow is more efficient in removing high risk inhalable particles than the vortex air flow. This difference in efficiency can be achieved by, for example, a centrifugal fan throwing high risk inhalable particles via an air flow onto the wall of the centrifugal fan, whereby the particles can fall out of the air, especially for small size inhalable particles.

Fig. 5 is a side view schematic of a centrifugal fan 600 of an HVACR system according to an embodiment. The centrifugal fan 600 includes a volute 610 having an inner surface and a curved inlet shroud 670. It should be understood that centrifugal fan 600 may be a direct drive fan or a pulley drive fan. It should also be appreciated that in an embodiment, the centrifugal fan 600 may be a volute-less fan without a volute 610 (see FIG. 6). The volute 610 defines an air outlet 660. The curved inlet shield 670 defines an air inlet 680. The air inlet 680 has an inlet airflow cross-sectional area that is substantially perpendicular to an outlet airflow cross-sectional area of the air outlet 660. In such embodiments, air or other gas may flow into the air inlet 680 (e.g., in a direction toward the paper) and then out of the air outlet 660 in a direction perpendicular to the direction of the air entering the air inlet 680 (e.g., toward the left side of the paper).

Centrifugal fan 600 further includes an impeller 620, the impeller 620 being mounted for rotation within volute 610 about an axis of rotation 695. Impeller 620 has a plurality of fan blades 625. The plurality of fan blades 625 have an outer surface.

Centrifugal fan 600 also includes a light source 640, where light source 640 is disposed at a first end of centrifugal fan 600 opposite a second end of centrifugal fan 600 where air outlet 660 is located. Centrifugal fan 600 includes a window 630 and a reflector 650 covering window 630. The light source 640 is surrounded by the window 630 and the reflector 650. It should be understood that window 630 is a portion of volute 610 such that the shape of volute 610 is unchanged. Centrifugal fan 600 includes a photocatalyst layer 690 disposed on the inner surface of volute 610 and the outer surface of impeller 620 (including the outer surface of the plurality of fan blades 625). It should be appreciated that although only a small number of fan blades 625 are shown in fig. 5, those skilled in the art will appreciate an impeller configuration that includes a full set of fan blades arranged around the circumference of the impeller 620. It should also be understood that in fig. 5, the photocatalyst layer 690 disposed on the outer surface of the impeller 620 is for illustrative purposes. In one embodiment, the photocatalyst layer 690 is disposed on an outer surface of the impeller 620 including an outer surface of the plurality of fan blades 625. For details of the embodiment of fig. 5, see also fig. 10A and 10B.

Fig. 5 illustrates how light (e.g., UVA, UVB, UVC, visible light, etc.) emitted from a light source 640 interacts with a photocatalyst layer 690 to remove/reduce pathogens from air. Embodiments provided herein may provide an efficient solution to provide a decontamination product with full airflow treatment to remove or reduce pathogens (viruses, bacteria, etc.) without creating an air pressure drop (i.e., without increasing airflow resistance), without changing the shape of the volute (and thus the characteristics of the centrifugal fan (e.g., airflow, noise, etc.), and without requiring additional space.

Fig. 6 is a perspective view of a voluteless centrifugal fan 500 of an HVACR system according to an embodiment. The fan 500 includes an impeller 510 having a plurality of fan blades 520. The blower 500 also includes a photocatalyst layer (not shown, see, e.g., 690 of FIG. 5) disposed on an outer surface of the impeller 510 (including the outer surface of the blades 520). In one embodiment, the photocatalyst layer may be on an interior surface of a fan section panel (not shown) of fan 500. A light source (not shown, see, e.g., 640 of fig. 5) may be positioned such that light emitted from the light source (e.g., UVA, UVB, UVC, visible light, etc.) may interact with and completely cover the photocatalyst layer, thereby removing/reducing pathogens from the air.

Fig. 7 shows simulation results 700 of light intensities of two light sources (e.g., two elongated lamps) in a centrifugal fan (e.g., a PCO centrifugal fan) according to an embodiment. In the simulation, two 10 watt UVC light sources were simulated. Each light source is similar to the light source of fig. 13A and 13B (described later, in which each light source extends in the length direction from one end of the light source to which a power supply is connected to the tip of the light source). In fig. 7, UVC light intensity is in units of microwatts per square centimeter.

Coordinates

730 and 740 represent the size (in millimeters) of the air outlet (e.g., substantially rectangular) of the centrifugal fan. Coordinate 750 represents light intensity. Along each elongated UVC lamp, the intensity (710 and 720) decreases (toward the tip of the lamp) or increases (away from the tip of the lamp) along the length of the lamp, as shown in fig. 7. It should be appreciated that figure 7 demonstrates the importance of the location of the light source(s) (and thus the resulting light intensity that inactivates the virus). Embodiments disclosed herein may achieve an optimal position (and thus light intensity) at a desired air coverage.

Fig. 8 shows simulation results 800 of time and light dose required to inactivate pathogens (e.g., viruses) in a centrifugal fan, according to an embodiment. In the simulation of fig. 8, an air flow rate of 500 cubic meters per hour or so is provided, and the size of the chamber (the inner space through which the air flow passes) of the centrifugal fan is 30 cubic meters or so. As shown in fig. 8, the minimum UVC dose to inactivate lipophilic viruses (all or almost all viruses) in a centrifugal fan is equal to or about 10,000 (microwatts seconds per square centimeter) and the minimum time to achieve the minimum UVC dose to inactivate viruses (all or almost all viruses) in a centrifugal fan is at or about 42 minutes. It should be appreciated that fig. 8 demonstrates the importance of the light intensity (and thus the position) of the light source(s) with respect to time. The greater the light intensity, the more virus inactivated in a given time. Embodiments disclosed herein may achieve optimal light intensity within a desired air coverage.

Table 1 shows the test results of noise and air flow variation in the centrifugal fan according to the embodiment. In table 1, the column "baseline" represents the baseline values (without any light source) for noise, input power (in watts), and airflow (in cubic meters per hour at 12 pascals). The column "1 lamp/fan" represents the values of noise, input power (in watts) and air flow (in cubic meters per hour at 12 pascals) relative to a reference value (with one light source). The column "2 lamps/fans" represents the values of noise, input power (in watts) and air flow (in cubic meters per hour at 12 pascals) relative to a reference value (with two light sources).

As shown in table 1, since one light source (for example, see the light sources in fig. 13A and 13B) is added to the centrifugal fan, noise in the centrifugal fan is increased by 1.2dB or about 1.2dB with respect to the reference value, and the airflow in the chamber of the centrifugal fan is reduced by 3% or about 3% with respect to the reference value (airflow is reduced because the light source occupies a space). Since two light sources (see, for example, the light sources in fig. 13A and 13B) are added to the centrifugal fan, the noise in the centrifugal fan increases by 1.3dB or about 1.3dB with respect to the reference value, and the airflow in the chamber of the centrifugal fan decreases by 8% or about 8% with respect to the reference value (airflow decreases because the light sources occupy space). Table 1 shows that embodiments disclosed herein do not significantly increase noise and/or reduce airflow, and that a user may select different configurations (e.g., one lamp or two lamps) based on the user's requirements (e.g., noise, airflow, light intensity, etc.).

Fan coil-2 fan	Reference line		1 Lamp/Fan	2 lamp/fan
					Noise dB (A)	33.4	34.6	34.7
Variation dB (A)	0	+1.2	+1.3
				Input power W	49.4	48.6	48.1
Air flow CMH @12Pa	625	604	575
				Variations in	0％	-3％	-8％

TABLE 1

Fig. 9 shows test results 910 of a formaldehyde cleanup test according to an embodiment. It should be understood that light (emitted from the light source) may be emitted at the photocatalyst layerTo react with the photocatalyst to generate hydroxyl radicals (which can oxidize biological particles in the air and convert volatile organic compounds to H₂O and CO₂To inactivate or kill pathogens). For example, UVC photons may react with a photocatalyst to generate hydroxyl radicals, which may oxidize airborne biological particles and/or convert volatile organic compounds to H₂O and CO₂. Line 912 shows the results of a photocatalytic oxidation plugged formaldehyde cleanup test in a delivery line (e.g., tank 300 of fig. 3). Line 914 shows the results of the photocatalytic oxidation formaldehyde purification test in a centrifugal fan. Figure 9 shows that the centrifugal fan configuration can achieve a greater formaldehyde reduction over the duct (duct) configuration for a given period of time.

10A-15E are perspective views of a centrifugal fan having light source(s) according to some embodiments. It should be understood that throughout this disclosure, one or more components having the same reference number in fig. 10A-15E are the same component or components, unless otherwise noted.

Fig. 10A and 10B are perspective views of a centrifugal fan 1000 having a light source(s) according to an embodiment. Fig. 10A is an end view of the centrifugal fan 1000, and fig. 10B is a side view of the centrifugal fan 1000.

The centrifugal fan 1000 includes a volute 1010 having an inner surface and a curved inlet shroud 1070. The volute 1010 defines an air outlet 1060. The curved inlet shield 1070 defines an air inlet 1080. The air inlet 1080 has an inlet airflow cross-sectional area that is substantially perpendicular to the outlet airflow cross-sectional area of the air outlet 1060.

Centrifugal fan 1000 further includes an impeller 1020, the impeller 620 being mounted for rotation within volute 1010 about an axis of rotation 1095. Impeller 1020 has a plurality of fan blades 1025. A plurality of fan blades 1025 have an outer surface. The plurality of fan blades 1025 are generally circumferentially spaced apart and generally project radially outward from, for example, axis 1095.

Centrifugal fan 1000 also includes a light source 1040, where light source 1040 is disposed at a first end of centrifugal fan 1000 opposite a second end (where air outlet 1060 is located) of centrifugal fan 1000. The centrifugal fan 1000 includes a window 1030 that allows light to pass through and a reflector 1050 that covers the window 1030 and reflects the light. The light source 1040 is surrounded by the window 1030 and the reflector 1050 and is configured to emit light. In an embodiment, the window 1030 may be part of the volute 1010 such that the shape of the volute 1010 is unchanged. Centrifugal fan 1000 includes a photocatalyst layer (not shown, see fig. 5) disposed on an inner surface of volute 1010 and an outer surface of impeller 1020 (including an outer surface of plurality of fan blades 1025). It should be appreciated that although a small number of fan blades 1025 are shown in FIG. 10B, those skilled in the art will appreciate an impeller structure that includes a full set of fan blades arranged around the circumference of the impeller 1020. In one embodiment, the photocatalyst layer is disposed on the entire (or nearly the entire) inner surface of the volute 1010 and the entire (or nearly the entire) outer surface of the impeller 1020 (including the entire (or nearly the entire) outer surface of the plurality of fan blades 1025).

In fig. 10B, because window 1030, light source 1040, and reflector 1050 are disposed at one end of centrifugal fan 1000, which is opposite the other end of centrifugal fan 1000 where air outlet 1060 is located, and because there is space between the plurality of fan blades 1025 and the plurality of fan blades 1025 are rotating at all times during operation, light source 1040 is able to emit light on the entire (or nearly entire) inner surface of light volute 1010 and on the entire (or nearly entire) outer surface of impeller 1020 (including the entire (or nearly entire) outer surface of the plurality of fan blades 1025). It should be appreciated that the reflector 1050 may be positioned to achieve a desired and/or required light coverage (on the photocatalyst layer) and/or to prevent light (e.g., UV light) leakage.

It should be understood that the light sources may be of the same type for the light sources described in all the figures herein. One light source may comprise at least one lamp (e.g., at least one mercury lamp or at least one LED lamp). A light source may also comprise at least one light emitting diode light source. The light source may be configured to emit UVA, UVB, UVC, and/or visible light. The light may be emitted, for example, as ultraviolet germicidal radiation, to inactivate or kill airborne pathogens (e.g., UVC light may directly kill airborne pathogens), or onto a photocatalyst layer to contact lightThe mediator reacts to generate hydroxyl radicals (which can oxidize airborne biological particles and convert volatile organic compounds to H₂O and CO₂To inactivate or kill pathogens). For example, UVC (e.g., having a wavelength of 254nm or about 254 nm) photons can damage cellular and viral RNA/DNA. The UVC photons may also react with a photocatalyst to generate hydroxyl radicals, which may oxidize airborne biological particles and/or convert volatile organic compounds to H₂O and CO₂。

In fig. 10A, the light source 1040, the window 1030, and the reflector 1050 extend from a first side 1011 of the volute 1010 to a second side 1012 of the volute 1010. In fig. 10A and 10B, a portion of the volute 1010 is replaced by the window 1030, but the shape of the volute 1010 is not changed. That is, the window 1030 is part of the volute 1010. Since the shape of the volute 1010 is not changed, the window 1030 does not change the noise and airflow in the chamber of the centrifugal fan 1000 (see table 1). In one embodiment, the window 1030 is made of a material (e.g., quartz glass) that has a high transmittance of light wavelengths for light emitted from the light source to allow UV light to pass through and enter the interior space of the volute 1010.

In one embodiment, reflector 1050 has a curved shape. The reflector 1050 may be made of polished aluminum or polished stainless steel or teflon to reflect light emitted from the light source 1040 back into the volute 1010 (e.g., to prevent light leakage).

In another embodiment, a set of light sources, windows, and reflectors may be disposed at position a (above the scroll 1010) and/or position B (at the bottom of the scroll 1010), respectively. Position a and position B are vertically aligned with the axis of rotation 1095.

The light source 1040 includes a controller 1041 (e.g., controlling an actuator and/or ballast) connected to an AC and/or DC power source 1042.

The embodiments disclosed herein do not affect the size and/or length and/or shape of the air handling unit (and/or centrifugal fan 1000), do not increase the air pressure drop (equal to or about 0Pa pressure drop), do not add additional resistance to the airflow, and provide optimal efficiency and efficiency because all (or nearly all) of the air passing through the air handling unit can pass through the centrifugal fan 1000 (e.g., through the impeller 1020 and through the interior space of the volute 1010) so that all (or nearly all) of the air can be treated (e.g., by the photocatalytic oxidation and/or ultraviolet germicidal irradiation solutions disclosed herein).

It will be appreciated that viruses (e.g. COVID-19 virus) typically reside in a droplet core, the size of which is 0.5 microns or about 0.5 microns to 5 microns or about 5 microns (see figure 4). The droplet nuclei can be separated by e.g. centrifugal force to the inner surface of a centrifugal fan according to patent application CN108786284A, the entire disclosure of which is incorporated herein by reference. The concentration of the droplet core can help improve the inactivation efficiency of light (e.g., UVC light) and photocatalysis (e.g., the solutions described herein).

Fig. 11A and 11B are perspective views of a centrifugal fan 1100 having light source(s) according to an embodiment. Fig. 11A is an end view of centrifugal fan 1100, and fig. 11B is a side view of centrifugal fan 1100. Fig. 11C and 11D are perspective views of a portion of an impeller with a baffle.

Centrifugal fan 1100 includes a shaft 1090, and shaft 1090 drives impeller 1020 in rotation (e.g., by a motor via shaft 1090). In one embodiment, shaft 1090 is aligned with axis of rotation 1095. The

light sources

1043, 1044 are disposed in an empty space inside the curved inlet shield 1070 (e.g., on the axis of rotation 1095 or at a location remote from the axis of rotation 1095). A support (1110, 1120) is provided on the volute 1010 to support the light source(s) 1043, 1044. In one embodiment, each light source(s) 1043, 1044 may have an H-shaped lamp. In one embodiment, the impeller 1020 may have a partition 1021. The light source 1044 extends from the first side 1011 of the volute 1010 towards the partition 1021, and an end of the light source 1044 is disposed near the partition 1021 (for better light coverage). The light source 1043 extends from the second side 1012 of the volute 1010 toward the partition 1021, and an end of the light source 1043 is disposed proximate the partition 1021 (for better light coverage). In one embodiment, the partition 1021 divides the chamber (1150 and 1160) of the impeller 1020 into two separate spaces. The partition 1021 may have a disc shape. Fig. 11C is a perspective view of a portion of the impeller 1020a with a partition 1021 a. The partition 1021a may have a disk shape and connect the hub 1180 of the impeller 1020a and the blade ring 1170. The impeller 1020a has a single suction inlet 1130, and a partition 1021a is on one side of the impeller 1020 a. Fig. 11D is a perspective view of a portion of an impeller 1020b having a partition 1021 b. The impeller 1020b has a double suction inlet 1140, and a partition 1021b is located in the middle of the impeller 1020 b.

Referring again to fig. 11A and 11B, the configuration of the light source(s) 1043, 1044 can provide direct light to the airflow and photocatalyst layer on the inner surface of the volute 1010 and the outer surface of the impeller 1020 (including the outer surface of the plurality of fan blades 1025).

Fig. 12A and 12B are perspective views of a centrifugal fan 1200 having light source(s) according to embodiments. Fig. 12A is an end view of centrifugal fan 1200, and fig. 12B is a side view of centrifugal fan 1200. In fig. 12A and 12B, each light source(s) 1045, 1046 may have an annular lamp that is aligned with the shape of the curved inlet shield 1070. In one embodiment, the

light sources

1045, 1046 are disposed near or at the

ends

1011, 1012 of the centrifugal fan 1100 near or over the curved inlet shield 1070.

Embodiments disclosed herein may provide the light source(s) 1045, 1046 as, for example, a fairing ring(s) for air inlet fairing at the air inlet 1080. Due to the shape and position of the light source(s) 1045, 1046, such embodiments do not increase the resistance to airflow and provide optimal aerodynamics. In such embodiments, due to the location of the light source(s) 1045, 1046, some of the light from the light source(s) 1045, 1046 may not be directly emitted on the airflow and photocatalyst layer on the inner surface of the volute 1010 and the outer surface of the impeller 1020 (including the outer surface of the plurality of fan blades 1025), and the power efficiency of the light may not be optimal.

Fig. 13A and 13B are perspective views of a centrifugal fan 1300 having light source(s) according to an embodiment. Fig. 13A is an end view of centrifugal fan 1300, and fig. 13B is a side view of centrifugal fan 1300.

In fig. 13A and 13B, the light source 1047 is inserted (e.g., through a hole opened on the volute 1010) into the volute 1010 and extends in a horizontal direction (substantially parallel to an upper wall of the volute 1010) toward the air outlet 1060. In one embodiment, the light source 1047 comprises an elongated lamp extending near or at the air outlet 1060. The light source 1047 is disposed above the impeller 1020 and closer to the upper wall of the volute 1010 (where the density of pathogens may be relatively high) than to the impeller 1020.

The embodiments disclosed herein provide a relatively close distance of light (from the light source 1047) to the upper wall of the volute 1010 (where the density of pathogens is relatively high) to directly remove/kill pathogens (i.e., kill pathogens with high efficiency), and to provide direct light from the light source 1047 onto a majority of the photocatalyst layer on the inner surface/wall of the volute 1010 and the outer surface of the impeller 1020 (including the outer surface of the plurality of fan blades 1025). It will be appreciated that such embodiments may not be optimal for aerodynamics, but provide a balanced solution with respect to efficiency of pathogen killing and aerodynamics.

Fig. 14A and 14B are perspective views of a centrifugal fan 1400 with light source(s) according to embodiments. Fig. 14A is an end view of centrifugal fan 1400, and fig. 14B is a side view of centrifugal fan 1400.

In fig. 14A and 14B, the volute 1010 includes a volute tongue 1013. The volute tongue 1013 is disposed proximate to the air outlet 1060. In one embodiment, the volute tongue 1013 has an arcuate shape for air rectification (to rectify airflow) to act as a reflector made of polished aluminum or polished stainless steel or polytetrafluoroethylene to reflect light emitted from the light source 1048 back into the volute 1010 (e.g., to prevent light leakage). In one embodiment, the volute 1013 provides at least a partial support for the light source 1048. The light source 1048 extends from a first side 1011 of the volute 1010 to a second side 1012 of the volute 1010. In one embodiment, the lower end of the air outlet 1060, the volute 1013, and the axis of rotation 1095 are substantially aligned with one another (e.g., horizontally). The embodiments disclosed herein may be optimized for aerodynamics.

15A-15E are perspective views of a centrifugal fan having light source(s) according to embodiments. FIG. 15A is a side view of an air handling unit 1500 including a centrifugal fan 1530. Cell 1500 includes an outlet opening 1520 and a coil 1510. In one embodiment, the coil 1510 comprises aluminum coil fins for blocking exit light (e.g., ultraviolet light). It should be appreciated that coil 1510 does not increase the air pressure drop. The cell 1500 also includes a barrier 1540 disposed at or near the return air inlet of the cell 1500. In one embodiment, barrier 1540 is a honeycomb aluminum barrier to block entrance light (e.g., ultraviolet light). It should be appreciated that the barrier 1540 causes little or no air pressure drop.

Fig. 15C is a view of the end 1502 of the cell 1500 facing the outlet opening 1520 with the coil 1510 visible. Tested, in fig. 15C, the UV intensity outside of the egress opening 1520 was equal to or about 0.0 microwatts per square centimeter. Fig. 15D is a perspective view of the top 1503 of the unit 1500 showing the coil 1510 and centrifugal fan(s) 1530. Fig. 15E is a view of the end 1504 of the cell 1500 facing the barrier 1540. Tested, in fig. 15E, the UV intensity outside of the barrier 1540 is equal to or about 0.0 microwatts per square centimeter. FIG. 15B is a view of the end 1501 of the cell 1500 without the barrier 1540. The UV intensity at this location (where the barrier 1540 is located in fig. 15E) was tested to be equal to or about 56.1 microwatts per square centimeter in fig. 15B.

Figures 16A-16D are schematic illustrations of a photocatalyst layer disposed on a surface of a centrifugal fan (which refers to, for example, an inner surface of a volute and/or an impeller including a fan blade, or an outer surface of a volute and/or a fan blade), according to some embodiments.

Fig. 16A shows primer layer 1620 disposed on the surface of the centrifugal fan. The primer material may be polyurethane, a passivating agent, or the like. In one embodiment, the surface of the centrifugal fan is made of plastic 1630. The photocatalyst layer 1610 may be titanium dioxide (TiO) disposed on the surface (top) of the primer layer 1620₂) And (3) a layer. In fig. 16B, the surface of the centrifugal fan is made of galvanized steel (1640Zn, 1650 steel, and 1660 Zn). It should be understood that primer layer 1620 is configured to hold photocatalyst layer 1610 on a surface (1630 or 1640-1660). The fan blades may be made of plastic orGalvanized steel, etc.

In one embodiment, a primer layer may be added to the surface (1630 or 1640) and TiO may be added at 10nm (particle size)₂Alcohol compound and 5nm (particle diameter) TiO₂Aqueous solutions (e.g., TiO with water)₂Powder). It should be understood that TiO₂The smaller the particle size, the better the air filtration/disinfection efficiency.

FIG. 16C shows a photocatalyst layer 1670 disposed on the surface of a centrifugal fan. In one embodiment, the surface is made of plastic 1680. Photocatalyst layer 1670 includes titanium dioxide (TiO) with titanium dioxide on polyurethane foam or metal foam₂) And (3) a layer. In fig. 16D, the surface of the centrifugal fan is made of galvanized steel (1690 zinc, 1691 steel and 1692 zinc). In one embodiment, foamed TiO may be added to the surface (1680 or 1690-1692)₂Layer (e.g. adding TiO on foam Nickel)₂Or adding TiO on polyurethane sponge₂). It should be understood that the foam may be TiO₂A layer (relatively thick) is applied to the surface of the volute. For impellers or fan blades, TiO is due to foam₂The layer is relatively thick and thus aerodynamics may not be optimal.

It is understood that the photocatalyst layer (1610-. It should also be appreciated that the sintering process may assist in sintering from, for example, TiO₂Removing unwanted material from the layer (1620, 1670) to make the TiO₂May be exposed to more air or may be more directly exposed to air.

It should also be understood that TiO₂Is low cost and can be used in combination with UV light (UVA, UVB and UVC; they have relatively short wavelength and high energy, can activate TiO₂And hole electron pairs can be generated to produce hydroxyl radicals). It is also understood that UVC can kill pathogens directly (without relying on a photocatalyst layer).

In one embodiment, the photocatalyst layer may comprise TiO₂Or ZnO or any other suitable material to work with the UV lamp(s). In another embodiment, the photocatalyst layer may include doped TiO₂Or graphitic carbonitride (e.g., g-C3N4) or any other suitable material to work with the visible light from the visible lamp(s) (e.g., LED to generate hydroxyl radicals). The photocatalyst layer may comprise a plurality of semiconductor materials, CdS, WO₃、SnO₂、Fe₂O₃、ZrO₂、PbS、SiO₂、ZnS、SrTiO₃And/or graphene-based photocatalysts, and the like.

It will be appreciated that in order to achieve maximum disinfection, a UVC (e.g., having a wavelength of 254nm or about 254nm in one embodiment) light source is preferred, which forms a combination of photocatalytic oxidation and ultraviolet germicidal irradiation. Ultraviolet light leakage may be controlled to levels below national standards (e.g., equal to or about 5 uW/cm)²)。

It should also be appreciated that UVA light sources are safer for humans. For example, the exposure limit of UVA (e.g., having a wavelength of 370nm or about 370nm to 380nm or about 380 nm) is 10,000 times or about 10,000 times the exposure limit of 254nm UVC. For example, UVA exposure limits at 8 hours at 254nm or about 254nm are 6.0mJ/cm²Or about 6.0mJ/cm²UVA exposure limit at 370nm or about 370nm wavelength of 3.2 x 10⁵ mJ/cm²Or about 3.2 x 10⁵mJ/cm²Or a UVA exposure limit of 5.7 x 10 at a wavelength of 385nm or about 385nm⁵ mJ/cm²Or about 5.7 x 10⁵mJ/cm². It should also be understood that doped TiO working with visible light sources₂Or g-C3N4 does not pose a safety risk to humans.

Embodiments disclosed herein may take advantage of the extensive contact between the airflow and the impeller blades and the inner wall of the volute, thereby increasing the efficiency of killing pathogens such as codv-19.

Self-cleaning, regeneration and superhydrophilicity tests have been performed on the photocatalyst layer. After e.g. UV light emitted on the photocatalyst layer, the photocatalyst layer shows super-hydrophilicity. With the movement of the water spray and the impeller, it is possible to easily performThe photocatalyst layer can be cleaned of dirt or can be self-cleaned, and the photocatalyst layer can be regenerated by spraying water. The photocatalyst layer does not need to be replaced or replaced for a long time. In the self-cleaning test, TiO₂Showing photoinduced superhydrophilicity. For example, for 10nm TiO with a contact angle of 60 ° or about 60 °₂The contact angle becomes 16 ° or about 16 ° after 30 minutes or about 30 minutes of UVC light irradiation. In the regeneration test, water spray can clean the photocatalyst layer and regenerate TiO from inactivation₂。

The method comprises the following steps:

it is to be understood that any of aspects 1-19, 20, and 21 may be combined with one another.

Aspect 1. A centrifugal fan for a heating, ventilation, air conditioning and refrigeration (HVACR) system, the centrifugal fan comprising:

a volute having an inner surface, the volute defining an air outlet, a curved inlet shroud defining an air inlet, and the air inlet having an inlet airflow cross-sectional area that is substantially perpendicular to an outlet airflow cross-sectional area of the air outlet;

an impeller mounted for rotation within the volute about an axis of rotation, the impeller having a plurality of fan blades, and the plurality of fan blades having an outer surface; and

a light source for emitting light from a light source,

wherein an inner surface of the volute and an outer surface of the plurality of fan blades include a photocatalyst layer,

wherein the light source is configured to emit light onto the photocatalyst layer.

Aspect 2. The centrifugal fan of aspect 1, the volute being made of plastic, the photocatalyst layer comprising: a primer layer disposed on an inner surface of the volute and an outer surface of the plurality of fan blades, and a titanium dioxide layer disposed on a surface of the primer layer.

Aspect 3. The centrifugal fan of aspect 1, the volute being made of galvanized steel, the photocatalyst layer comprising: a primer layer disposed on an inner surface of the volute and an outer surface of the plurality of fan blades, and a titanium dioxide layer disposed on a surface of the primer layer.

Aspect 4. The centrifugal fan of aspect 1, the volute being made of plastic, the photocatalyst layer comprising a titanium dioxide layer having titanium dioxide on polyurethane foam or metal foam, the titanium dioxide layer being disposed on an inner surface of the volute and an outer surface of the plurality of fan blades.

Aspect 5. The centrifugal fan of aspect 1, the volute being made of galvanized steel, the photocatalyst layer comprising a titanium dioxide layer having titanium dioxide on foamed polyurethane or foamed metal, the titanium dioxide layer being disposed on an inner surface of the volute and an outer surface of the plurality of fan blades.

Aspect 6. The centrifugal fan according to any one of aspects 1 to 5, wherein a photocatalyst layer is coated or sintered on an inner surface of the scroll casing and an outer surface of the plurality of fan blades.

Aspect 7. The centrifugal fan of any of aspects 1-6, wherein the light source is configured to emit UVA light.

Aspect 8. The centrifugal fan of any of aspects 1-6, wherein the light source is configured to emit UVC light.

Aspect 9. The centrifugal fan according to any one of aspects 1 to 7, wherein the light source is a mercury lamp.

Aspect 10. The centrifugal fan of any of aspects 1-6, wherein the light source is a light emitting diode light source.

Aspect 11. The centrifugal fan according to any of aspects 1-10, wherein the volute comprises a window that allows light to pass into the volute interior space, the centrifugal fan comprises a reflector covering the window, the reflector is configured to reflect light, and the light source is surrounded by the window and the reflector.

Aspect 12. The centrifugal fan of aspect 11, the window being made of quartz glass, the reflector being made of polished aluminum or polished stainless steel or polytetrafluoroethylene,

wherein the light source, window, and reflector extend from a first side of the volute to a second side of the volute.

Aspect 13. The centrifugal fan of any of aspects 1-10, wherein the light source is disposed inside a chamber of the centrifugal fan.

Aspect 14. The centrifugal fan of aspect 13, wherein the light source comprises a first light source and a second light source, the impeller comprises a baffle, the first light source extends from a first side of the volute toward the baffle, and the second light source extends from a second side of the volute toward the baffle.

Aspect 15. The centrifugal fan according to any of aspects 1-10, wherein the light source is annular and disposed on a side of the volute.

Aspect 16. The centrifugal fan according to any of aspects 1-10, wherein the light source comprises a first light source and a second light source, the first light source being annular and disposed at a first side of the volute, the second light source being annular and disposed at a second side of the volute.

Aspect 17. The centrifugal fan according to any one of aspects 1-10, wherein the light source is inserted into the volute in a direction toward an air outlet of the volute.

Aspect 18. The centrifugal fan of any of aspects 1-10, wherein the light source is disposed inside the volute and proximate to the air outlet, the light source extending from a first side of the volute to a second side of the volute.

Aspect 19. The centrifugal fan of aspect 18, wherein the volute comprises a reflector configured to reflect light, the light source being disposed on the reflector.

Aspect 20. A method of configuring a centrifugal fan of a heating, ventilation, air conditioning and refrigeration (HVACR) system, the centrifugal fan comprising a volute having an inner surface, the volute defining an air outlet, and a curved inlet shroud defining an air inlet, and the air inlet having an inlet airflow cross-sectional area that is substantially perpendicular to an outlet airflow cross-sectional area of the air outlet; an impeller mounted for rotation within the volute about an axis of rotation, the impeller having a plurality of fan blades, and the plurality of fan blades having an outer surface; and a light source for emitting light from the light source,

the method comprises the following steps:

coating or sintering a photocatalyst layer on an inner surface of the volute and an outer surface of the plurality of fan blades, an

Light is emitted by the light source onto the photocatalyst layer.

Aspect 21. A heating, ventilation, air conditioning and refrigeration (HVACR) system, the system comprising:

a compressor, a condenser, an expansion device, and an evaporator fluidly connected; and

a centrifugal fan for a condenser or evaporator, the centrifugal fan comprising:

an impeller mounted for rotation within the volute about an axis of rotation, the impeller having a plurality of fan blades, and the plurality of fan blades having an outer surface;

a light source for emitting light from a light source,

The terminology used in the description is for the purpose of describing particular embodiments and is not intended to be limiting. The terms "a", "an" and "the" are also inclusive of the plural form unless specifically stated otherwise. The terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.

With respect to the foregoing description, it will be understood that specific changes may be made in the form, size and arrangement of the components and construction materials employed without departing from the scope of the disclosure. It is intended that the specification and described embodiments be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A centrifugal fan, comprising:

a volute having an inner surface, the volute defining an air outlet, and a curved inlet shroud, the curved inlet shroud defining an air inlet, and the air inlet having an inlet airflow cross-sectional area that is perpendicular to an outlet airflow cross-sectional area of the air outlet;

a light source for emitting light from a light source,

2. The centrifugal fan as recited in claim 1, wherein the volute is made of plastic or galvanized steel, and the photocatalyst layer comprises: a primer layer disposed on an inner surface of the volute and an outer surface of the plurality of fan blades, and a titanium dioxide layer disposed on a surface of the primer layer.

3. The centrifugal fan of claim 1 wherein the volute is made of plastic or galvanized steel, and the photocatalyst layer comprises a titanium dioxide layer having titanium dioxide on polyurethane foam or metal foam, the titanium dioxide layer being disposed on an inner surface of the volute and an outer surface of the plurality of fan blades.

4. The centrifugal fan of claim 1, wherein a photocatalyst layer is coated or sintered on an inner surface of the volute and an outer surface of the plurality of fan blades.

5. The centrifugal fan of claim 1, wherein the light source is a mercury lamp.

6. The centrifugal fan of claim 1, wherein the light source is a light emitting diode light source.

7. The centrifugal fan of claim 1, wherein the volute comprises a window that allows light to pass into the volute interior space, the centrifugal fan comprises a reflector that covers the window, the reflector is configured to reflect light, and the light source is surrounded by the window and the reflector.

8. The centrifugal fan according to claim 7, wherein the window is made of quartz glass, the reflector is made of polished aluminum or polished stainless steel or polytetrafluoroethylene,

9. The centrifugal fan of claim 1, wherein the light source is disposed inside a chamber of the centrifugal fan.

10. The centrifugal fan of claim 9, wherein the light source comprises a first light source and a second light source, the impeller comprises a baffle, the first light source extends from a first side of the volute toward the baffle, and the second light source extends from a second side of the volute toward the baffle.

11. The centrifugal fan of claim 1 wherein the light source is annular and is disposed on a side of the volute.

12. The centrifugal fan of claim 1, wherein the light source comprises a first light source and a second light source, the first light source being annular and disposed at a first side of the volute, the second light source being annular and disposed at a second side of the volute.

13. The centrifugal fan of claim 1, wherein the light source is inserted into the volute in a direction toward an air outlet of the volute.

14. The centrifugal fan of claim 1 wherein the light source is disposed inside the volute and proximate to the air outlet, the light source extending from a first side of the volute to a second side of the volute.

15. The centrifugal fan of claim 14, wherein the volute comprises a reflector configured to reflect light, the light source being disposed on the reflector.

16. A heating, ventilation, air conditioning and refrigeration system, said system comprising:

a light source for emitting light from a light source,

wherein an inner surface of the volute and an outer surface of the plurality of fan blades include a photocatalyst layer thereon,