Embodiments of the invention are directed, in general, to oxidation technology for air purification systems and, more specifically, to a photocatalytic device that is adapted to be used with ductless heading and air conditioning systems.
Air-source heat pumps transfer heat between a building and the outside air. Heat pumps are popular because of their low cost and capability to do an excellent job of heating, cooling and dehumidifying. For homes without ducts, air-source heat pumps are available in a ductless version called a ductless mini-split heat pump that has two parts—an indoor unit and an outdoor unit. The mini-split products are typically super-efficient, energy star rated, and reliable. Both the indoor and outdoor units are basically silent. A mini-split heat pump provides a cost-effective, environmentally friendly, heating and cooling system.
A typical mini-split system is used to maintain indoor air quality. However, the primary function of most heating and air conditioning systems is to control the temperature and humidity of the air. Many indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical mini-split systems.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Often, an air cleaning device may be added to ducts in a heating and air conditioning systems to remove VOCs. Photocatalytic air cleaning devices are a common technique for indoor air purification and deodorization. A photocatalytic air cleaning device in a HVAC system is typically a duct-mounted device that comprises an ultraviolet lamp illuminating a photocatalytic filter to create free radicals that eliminate VOCs. Mini-split systems do not have ducts and, therefore, cannot use existing photocatalytic air cleaning devices.
In one embodiment, a photocatalytic device is adapted to be externally mounted on a mini-split system. The photocatalytic device may be mounted in any location that allows air flow to or from the mini-split to pass through the device. For example, the photocatalytic device may be mounted at an intake or supply vent or at an exhaust or return vent of a mini-split system.
In embodiments, the photocatalytic device comprises an ultraviolet light source and one or more catalyst substrates that are adapted to support a hydroxyl radical reaction with water vapor that results in hydro peroxides and hydroxyl ions. Such a photocatalytic device may be positioned at the intake of a mini-split system to clean the air space serviced by the heating and cooling system.
In other embodiments, the photocatalytic device may be adapted to be retrofitted to existing or installed mini-split systems.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The invention now will be described more fully hereinafter with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. One skilled in the art may be able to use the various embodiments of the invention.
Indoor unit 101 has an intake vent 109 that allows airflow to enter the unit and pass by or through heat exchanger 104. Exhaust vent 110 allows heated/cooled air to flow into the room for heating/cooling. In one embodiment, a photocatalytic device 111 is positioned near intake 109. Intake air flow passes through photocatalytic device 111, which may use ultraviolet light to significantly reduce the amount of microbials in the air space. This helps to reduce possible health problems associated with inhaling microbials. The ultraviolet light within photocatalytic device 111 is also beneficial in keeping the coils of heat exchange 104 free of mold, which increases system efficiency.
Ultraviolet (UV) light represents the frequency of light between 185 nanometers (nm) and 400 nm and is invisible to the naked eye. Within the UV spectrum lie three distinct bands of light: UV-A, UV-B, and UV-C. Longwave UV light (315 nm to 400 nm) or UV-A refers to what is commonly called “black light.” UV-B (280 nm to 315 nm) or midrange UV is the type of light that causes sunburn. Germicidal UV light (185 nm to 280 nm) or UV-C is effective in microbial control. Research has demonstrated that UV light between 254 nm and 265 nm is most efficient for microbial destruction. Germicidal lamps that produce the majority of their output in this range are the most effective in microbial control and destruction.
The photocatalytic structures 203 and 204 may be, for example, a hydrated catalytic matrix, such as a hydrated quad-metallic catalyst. When the ultraviolet light 202 impacts the photocatalytic structures 203 and 204, ozone is produced in the catalytic matrix. The catalyst supports a hydroxyl radical reaction with water vapor that results in hydro peroxides, hydroxyl ions, super oxide ions, passive negative ions hydroxides, and ozonide ions. These are highly reactive chemical species. The hydroxyl radicals are very strong oxidizers and will attack organic materials. This creates oxidation that helps to reduce odors, volatile organic compounds (VOCs), airborne viruses, bacteria, mold and other types of air pollution. The quad-metallic catalytic matrix may be comprised of Rhodium, Titanium, Silver and Copper for example. In other embodiments, other combinations of rare and noble metals may be used in a multi-metallic catalytic matrix.
Ultraviolet light source 202 may be, for example, a high-intensity, broad-spectrum ultraviolet bulb or tube. In other embodiments, the ultraviolet source may be a low pressure fluorescent quartz bulb or a medium pressure amalgam lamp. Ultraviolet light falls in the band of light between 185 nm and 400 nm. There are three distinct bands of light within the ultraviolet spectrum: UV-A, UV-B, and UV-C. Longwave UV light (315 nm to 400 nm), or UV-A, refers to what is commonly called “black light.” Midrange UV (280 nm to 315 nm), or UV-B, causes sunburn. Germicidal UV light (185 nm to 280 nm), or UV-C, is effective in microbial control. Research has demonstrated that the most efficient frequency for microbial destruction is between 254 nm and 265 nm within the UV-C band. Germicidal lamps that produce the majority of their output in this range will be the most effective in microbial control/destruction.
The curved reflectors 205 and 206 are positioned to reflect ultraviolet light from ultraviolet light source 202 to the internal face of photocatalytic structures 203 and 204. As a result, photocatalytic structures 203 and 204 receive both direct ultraviolet light from source 202 and reflected ultraviolet light from curved reflectors 205 and 206 as described in pending U.S. patent application Ser. No. 13/353,419, filed Jan. 19, 2012 and entitled “Photocatalytic Device with Curved Reflectors,” the disclosure of which is hereby incorporated by reference herein in its entirety. In one embodiment, reflectors 205 and 206 are curved in a manner that optimizes the distribution of ultraviolet light across the faces of photocatalytic structures 203 and 204. In other embodiments, bent reflectors may be preferable to curved reflectors 205 and 206. The size, shape and angle of such bent reflectors would be selected to optimize the uniform distribution of ultraviolet light across the surfaces of target structures 203 and 204. It will be understood that other convex shapes may also be used for the reflectors in other embodiments.
In operation, air flows through photocatalytic structure 203, past ultraviolet light source 202, then through photocatalytic structure 204. As the air exits photocatalytic structure 204, it is directed downward by shield 207 into the intake vent (not shown) of a mini-split system.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized that such equivalent constructions do not depart from the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
Number | Name | Date | Kind |
---|---|---|---|
2881854 | Uehre, Jr. | Apr 1959 | A |
4859329 | Fink | Aug 1989 | A |
5011609 | Fink | Apr 1991 | A |
5120435 | Fink | Jun 1992 | A |
5236585 | Fink | Aug 1993 | A |
5919422 | Yamanaka et al. | Jul 1999 | A |
6221314 | Bigelow | Apr 2001 | B1 |
6546883 | Fink et al. | Apr 2003 | B1 |
6752970 | Schwartz et al. | Jun 2004 | B2 |
6784440 | Fink et al. | Aug 2004 | B2 |
6849107 | Huffman | Feb 2005 | B1 |
6949228 | Ou Yang et al. | Sep 2005 | B2 |
6997185 | Han et al. | Feb 2006 | B2 |
7160566 | Fink et al. | Jan 2007 | B2 |
7635659 | Naganuma et al. | Dec 2009 | B2 |
7871518 | Ellis et al. | Jan 2011 | B2 |
7988923 | Fink et al. | Aug 2011 | B2 |
20030077211 | Schwartz et al. | Apr 2003 | A1 |
20030150708 | Fink | Aug 2003 | A1 |
20030230477 | Fink et al. | Dec 2003 | A1 |
20040016887 | Fink et al. | Jan 2004 | A1 |
20040056201 | Fink et al. | Mar 2004 | A1 |
20040156959 | Fink et al. | Aug 2004 | A1 |
20040197243 | Schwartz et al. | Oct 2004 | A1 |
20050163653 | Crawford et al. | Jul 2005 | A1 |
20050186124 | Fink et al. | Aug 2005 | A1 |
20050238551 | Snyder et al. | Oct 2005 | A1 |
20060144690 | Fink et al. | Jul 2006 | A1 |
20060163135 | Ellis et al. | Jul 2006 | A1 |
20060228275 | Rutman et al. | Oct 2006 | A1 |
20060266221 | Fink et al. | Nov 2006 | A1 |
20070000407 | Leong | Jan 2007 | A1 |
20070110860 | Fink et al. | May 2007 | A1 |
20090041617 | Lee | Feb 2009 | A1 |
20090183943 | Leistner et al. | Jul 2009 | A1 |
20090217690 | Silderhuis | Sep 2009 | A1 |
20110250125 | Fink et al. | Oct 2011 | A1 |
Number | Date | Country |
---|---|---|
2392106 | Aug 2000 | CN |
2922905 | Jul 2007 | CN |
101245939 | Aug 2008 | CN |
201135626 | Oct 2008 | CN |
20211178 | Nov 2002 | DE |
WO 2006134149 | Dec 2006 | WO |