US20010018964A1 - Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger - Google Patents
Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger Download PDFInfo
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- US20010018964A1 US20010018964A1 US09/812,972 US81297201A US2001018964A1 US 20010018964 A1 US20010018964 A1 US 20010018964A1 US 81297201 A US81297201 A US 81297201A US 2001018964 A1 US2001018964 A1 US 2001018964A1
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- air
- airstream
- regenerative heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
- F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
- F24F3/1411—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification by absorbing or adsorbing water, e.g. using an hygroscopic desiccant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F12/00—Use of energy recovery systems in air conditioning, ventilation or screening
- F24F12/001—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air
- F24F12/006—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air using an air-to-air heat exchanger
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D17/00—Regenerative heat-exchange apparatus in which a stationary intermediate heat-transfer medium or body is contacted successively by each heat-exchange medium, e.g. using granular particles
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J2217/00—Intercepting solids
- F23J2217/10—Intercepting solids by filters
- F23J2217/103—Intercepting solids by filters ultrafine [HEPA]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
- F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
- F24F2003/1458—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification using regenerators
- F24F2003/1464—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification using regenerators using rotating regenerators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/10—Rotary wheel
- F24F2203/1012—Details of the casing or cover
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/10—Rotary wheel
- F24F2203/104—Heat exchanger wheel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/10—Rotary wheel
- F24F2203/1068—Rotary wheel comprising one rotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/10—Rotary wheel
- F24F2203/108—Rotary wheel comprising rotor parts shaped in sector form
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2203/00—Devices or apparatus used for air treatment
- F24F2203/10—Rotary wheel
- F24F2203/1084—Rotary wheel comprising two flow rotor segments
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/56—Heat recovery units
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Filtering Materials (AREA)
Abstract
A heat recovery ventilator includes four rectangular regenerative heat exchangers, two blowers, a rotating air switch all disposed in a compact rectangular housing. The regenerative heat exchangers are made of a pleated HEPA filter material. The HEPA filter material captures at least 99.97% of particles having a diameter greater than 0.3 microns. Alternatively, the HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure. The regenerative heat exchangers are stationary with stationary seals between the outside and inside climate. One of the blowers blows a stale airstream out through the heat exchangers; the other blower blows a fresh airstream in through the heat exchangers. The rotating air switch operates in conjunction with the two blowers producing the necessary flow reversal through each regenerative heat exchanger to allow heat and moisture exchange between the stale airstream and the fresh airstream. The rotating air switch is completely on the inside climate side of the regenerative heat exchangers preventing freeze up in cold weather. The rotating air switch uses clearance seals.
Description
- This is a continuation application of U.S. application Ser. No. 09/082,171 filed May 20, 1998, which is a continuation-in-part of U.S. application Ser. No. 08/893,833 filed Jul. 11, 1997.
- Not Applicable
- This invention relates generally to heat transfer devices and air filtration devices, and in particular to heat exchangers, ventilators, and enthalpy exchangers along with air filters. The invention is particularly well-suited for air-to-air regenerative heat exchangers utilizing high efficiency particulate air (HEPA) filter material as the regenerative heat exchanger.
- Many individuals suffer from respiratory disorders, including allergies and asthma. In recent decades, scientists have known that poor quality indoor air seriously impacts human health. (American Lung Association, Washington, D.C. 20036, “Residential Air cleaning Devices: Types, Effectiveness and Health Impact”, 1997) Reduction of indoor pollution helps alleviate the suffering of these individuals. Efforts to reduce indoor air pollution have been directed to three areas: ventilation, air cleaning and source control. The problem of providing adequate indoor ventilation is well known.
- Modern energy efficient construction employs air “tight” structures to restrict infiltration of outside air. Lack of infiltration or natural ventilation has resulted in inadequate indoor ventilation. Standard 62-1989 of American Society of Heating, Refrigeration, and Air conditioning Engineers Inc. (ASHRAE), Atlanta, Ga., states, “When infiltration and natural ventilation are insufficient to meet ventilation air requirements, mechanical ventilation shall be provided. The use of energy recovery ventilation systems should be considered for energy conservation purposes in meeting ventilation requirements.” (Sec. 5.1.) Standard 62-1989 suggests 0.35 air changes per hour of continuous fresh air for living areas, but not less than 15 Cubic Feet per Minute (CFM) per person based on design occupancy. For a 2500 square-foot home, this equates to about 120 CFM.
- Bringing outside air into a structure for ventilation purpose can be problematic and expensive. Utilizing gas or electric heat to preheat separate ventilation air in winter is inefficient. For example, if the outside air is 20° C. colder than indoors, approximately 1.2 kW of heat is required to preheat the 120 CFM of required ventilation for a 2500 square-foot home. Use of a heat recovery ventilator is by far the most efficient way to ventilate, exchanging as much as 85% of the heat from warm (inside) exhaust air with the cool fresh air. In summer, use of a heat recovery ventilator also reduces air-conditioning load by exchanging cool dry exhaust air with warm humid fresh air. An “enthalpy” exchanger has been found to be particularly effective in humid climates.
- Some prior art air-to-air heat exchanger technology for home use utilize a cross-flow heat exchanger core, e.g., Lifebreath™ heat recovery ventilator by Nutech Energy Systems, Inc. of London, Ontario, Canada; TherMax TW Model room ventilators made by Thermax Energy Recycling Ventilation Systems, Division of Kooltronic, Inc. of Hopewell, New Jersey; NewAire™ air-to-air heat exchange ventilators made by Altech Energy of Madison, Wis.; U.S. Pat. No. 4,512,392 (Van Ee et al.) and U.S. Pat. No. 5,273,105 (Drake). A disadvantage of these devices is low heat exchanger effectiveness. The best theoretical effectiveness is approximately 70% for a cross-flow core. Practically, these devices only achieve a fraction of that effectiveness.
- Other prior art technology includes the use of a rotary heat recovery, wheel, e.g., Honeywell “Perfect Window” System energy recovery ventilator, available from Honeywell, Inc. of Golden Valley, Minn. This device employs a rotating regenerative wheel, as well as a fresh air filter and a room air filter. Two types of rotary heat recovery wheels may be used-a desiccant wheel to transfer moisture and also dry heat, or a sensible wheel to transfer only dry heat. (However, as is known in the art, the sensible wheel will transfer moisture when the air drops below the dew point temperature as the air passes through the regenerative wheel.) An advantage of this technology is that high heat exchanger effectiveness is possible. A disadvantage is that it requires an additional moving part, i.e., the regenerative wheel. This regenerative wheel (rotary heat recovery wheel) is approximately 16 inches in diameter for one model. It rotates at about 30 RPM. On one side of the wheel there is outside air. On the other side, there is indoor air. A brush seal is used around the rim of the wheel, and in freezing conditions, warm moist air flowing past the seal will condense and freeze forming frost. If the frost melts, it may migrate to the rim of the wheel and refreeze which can cause the wheel to freeze up. To prevent wheel freeze up, an electric preheater on the incoming air is used to warm the air to 5° F. (−15° C.).
- Yet other prior art technology which uses fixed, rotating or reciprocating heat exchanging beds or some method of periodically changing the airflow direction includes U.S. Pat. No. 3,978,912 (Penney et al.); U.S. Pat. No. 4,049,404 (Johnson); U.S. Pat. No. 4,391,321 (Thunberg); U.S. Pat. No. 4,493,366 (Ekman); U.S. Pat. No. 4,589,476 (Berner); U.S. Pat. No. 4,665,805 (Ekman); U.S. Pat. No. 4,688,626 (Tengesdal); U.S. Pat. No. 4,744,409 (Berner); U.S. Pat. No. 4,754,806 (Astle); U.S. Pat. No. 4,815,522 (Thunberg); U.S. Pat. No. 4,952,283 (Besik); U.S. Pat. No. 5,002,116 (Hoagland et al.); U.S. Pat. No. 5,050,667 (Berner et al.); U.S. Pat. No. 5,375,649 (Nilsen et al.) and D. A. Reay, “Heat Recovery Systems” (E. & F. N. Spoon, London, UK, 1979, pp. 17-35).
- Another problem with bringing in ventilation air concerns the quality of the fresh air introduced into the room or structure. In many places, allergens, such as, pollen or mold spores, and/or other particulates, such as, soot from vehicle exhaust or emissions from industrial sites, exist in the outside fresh air through much of the year. Thus source control of air-borne pollutants, e.g., controlling the source of the allergens and/or particulates from the incoming fresh air, is important. Filtering these allergens and/or particulates out of the incoming fresh ventilation air is important for individuals subject to respiratory diseases, including severe allergy sufferers or asthma sufferers.
- Filtering of the indoor air and trapping of pollutants, particulates and/or allergens generated in the indoor air is also important, since these too can create further respiratory distress. The indoor air generated pollutants, include, but are not limited to, cigarette smoke, pipe smoke, cigar smoke, smoke from the fireplace, organic pollutants, such as gasses from building materials, e.g. particle board, plywood, rugs, paints, varnishes, adhesives, or from cleaning supplies, personal care items, room deodorants, as well as other gases, such as radon, combustion products produced by unvented cooking and heating appliances, and particulates or allergens, such as, but not limited to, animal dander, dust mites, their feces and body parts, insect body parts, indoor molds and fungus, bacteria and viruses, etc.
- Air cleaning devices which remove pollutants, allergens and particulates of a certain sizes are shown in the disclosure in the American Lung Association, Washington, D.C. 20036, “Residential Air cleaning Devices: Types, Effectiveness and Health Impact, pages 9-16, 1997, the disclosure of which is hereby incorporated by reference. This publication discloses that air cleaning devices can be tabletop/console units, portable room air cleaners or central filtration units. The air cleaning devices use mechanical filters, electronic filters, hybrid filters (mechanical/electrostatic) filters, gas phase filters or ozone generators. The mechanical filter is typically a flat filter, a pleated filter, or a High Efficiency Particulate Air filter, having the acronym HEPA.
- Use of a pleated filter is also known in the medical airway ventilator art for use as a heat and moisture exchanger, see, PALL™ HME BB100F, PALL BIOMEDICAL, INC., Fajaido, PR. Here a maximum 24 hour usage is recommended. The filter is alleged to have “greater than 99.999% Bacterial/Viral removal Efficiency.”
- The HEPA filter technology is a known technology, see U.S. Pat. No. 4,629,482 to Davis and U.S. Pat. No. 4,685,944 to Allen et al. The “A” in the acronym HEPA is alternatively referred to as air, aerosol or arrestor. Thus a HEPA filter could be referred to as a “High Efficiency Particle Air” filter, a “High Efficiency Particle Aerosol” filter or a “High Efficiency Particle Arrestor” filter. The materials used for HEPA filters are typically glass fiber, glass-asbestos fiber, or other equivalent inorganic material and may include an organic binder material. The description of the HEPA filter unit, filter properties and testing are disclosed in the publications “Underwriters Laboratories, Inc., “Test Performance of High Efficiency Particulate Air Filter Units”, UL 586 (1977), pp. 5-9, International Atomic Energy Agency, Vienna (IAEA), 1970, “Air Filters for Use at Nuclear Facilities, Technical Report Series No. 122, pp. 16-42, the disclosures of which are hereby incorporated by reference. The disclosure of accordian type, V-shaped pleated HEPA filter, having closely spaced pleats and surrounded by a rectangular frame or casing on one or both edges is known. (see, IAEA Rept. 122 (supra), pp.16-17, and US Army Corps of Engineers, USACERL Technical Report (TR) FE-95/10, “Air Cleaning Systems and Indoor Air Quality: A Review”, pp 69-70, 1995).
- In the conventional HEPA filter art, the filter(filter unit)/filter material is typically defined by the testing standards used in the filter's certification. Interestingly, the testing standards are not identical testing methods. For example, the terms “true” HEPA and “ASHRAE” HEPA are commonly used in the HEPA filter art. The definition of each of these types of HEPA filters is governed by a different measurement standard. As used throughout herein, “true” HEPA filter and “true” HEPA filter material means a high efficiency particle air filter(filter material) which removes at least 99.97% of 0.3 micron dioctylphthalate (DOP) particles as measured by MIL-STD282, Method 102.9.1, May 28, 1956 (Military Standard Filter Units, Protective Clothing, Gas-Mask Components and Related Products: Performance-Test Methods, U.S. Government Printing Office, Washington, D.C., pp.33-38 and FIG. 9), the disclosure of which is hereby incorporated by reference. In the art, the particle removal referred to in MIL-STD-282 Method 102.9.1, May 28, 1956, or equivalent federal standards, is frequently shortened to “removal” or “capture” of “99.97% of all 0.3 micron particles” or “particles having a particle diameter of 0.3 microns” or “remove 99.97% of airborne particulate matter of 0.3 microns or greater”, or “remove a minimum of 99.97% of the particles having a size of 0.3 microns or greater” (see, U.S. Pat. Nos. 4,629,482 and 4,685,944). This convention is also used herein throughout, when referring to the true HEPA filter. As used therein throughout, “ASHRAE” HEPA filter and “ASHRAE” HEPA filter material means a high efficiency particle air filter (filter material) rated at least 85% (e.g. 85% or higher) Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, including appendix A, Gravimetric and Dust-Spot Procedures for Testing Air-Cleaning Devices Used in General Ventilation for Removing Particulate Matter”, hereinafter “Dust-Spot Procedure”, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, Ga., (pages 1-32) the disclosure of which is hereby incorporated by reference. Since the measurement testing methods differ (e.g., “DOP test procedure of MIL-
STD 282” versus “Dust-Spot Procedure” for particle removal efficiency ), it is difficult to do a direct comparison of filter efficiency of the two types of HEPA filters/filter materials. However, Table 3 of USACERL TR FE-95/10 (supra), page 24, the disclosure of which is hereby incorporated by reference, shows that an approximate rating of 80% to 98% ASHRAE Dust-Spot Test (Dust-Spot Efficiency Percentage) filter generally removes 35% to 80% of 0.3 micron DOP particles. - The use of these different standards, as well as equivalent standards and/or differing standards and specifications are known in the HEPA filter manufacturing art, for example HEPA filters (filter units) commercially available from HEPA Corporation of Anaheim, CA meet various standards and specifications, such as, Fed. Std. 209, U.L. 900 class 1 and 2, Mil-F-51068, ASHRAE 52-76, MIL. STD. 282, U.L. 586 and IES-RP-CC-001-86.
- Of particular interest is the HEPA filter unit commercially available as “3282 media” from Columbus Industries, Ashville, Ohio. This HEPA filter unit uses a HEPA grade mini-pleat material (media) made of glass micro fiber, e.g., submicron glass fibers with some synthetic fiber. This HEPA filter material captures 99.97% of all particles of 0.3 micron in diameter passing through it. The media has been tested by the manufacturer and is true HEPA up to approximately 7 feet per minute (FPM) media velocity. The traversely pleated (accordion style pleating) material is surrounded on four sides of its periphery with a chipboard frame. The V-spaced pleated sides, the top and the bottom of the filter unit are glued to a frame side, thus ensuring sealing around the frame perimeter. The frame has a frame opening on each of two opposed sides exposing the edges of the pleats. The mini-pleating is created by scoring the strip of HEPA filter material at specific size intervals, applying a glue bead separator on both sides of the strip at the location of the scoring, and accumulating the HEPA filter material, e.g., stacking the pleats into a finished accordian style. The use of the glue bead separator allows the pleating of the filter material to remain at a fixed pleat density, e.g., pleats per inch, once the glue cools and solidifies.
- Where an air cleaning device is used within a room, it acts to clean the air by removing particulates, pollutants and allergens. When the air cleaning device intercepts fresh air bearing particulates, pollutants and allergens, prior to dispersal into the room, it filters the fresh air of these materials, providing source control of the particulates, pollutants and allergens. This important function prevents mixing of the particulate, pollutants and allergens introduced in the fresh air with the indoor air.
- The HEPA filter is also known to be useful in the removal of radioactive or biologically hazardous materials particles from contaminated air before this air is exhausted to the atmosphere, see, U.S. Pat, No. 4,685,944, issued to Allan et. al. The HEPA filter material traps the particles in the airstream passing through the HEPA filter. The flow of air through this filter is unidirectional, thus large dust particles trapped on the HEPA filter easily impede the unidirectional air flow, causing the HEPA filter to plug up, requiring filter replacement.
- Most of the present air ventilation/heat recovery technology are large, heavy, bulky devices which are expensive, difficult to install, and complex, sometimes requiring preheating incoming cold air. Whereas the, standard console HEPA air cleaning devices utilizing a HEPA filter therein, such as, the HONEYWELL HEPA/CPZ™ air cleaner and the HONEYWELL ENVIRACAIRE™ air cleaner with HEPA filters, are small portable devices, which filter only the indoor air in the room. These HONEYWELL™ console air cleaning devices are commercially available, for example, from Allergy Asthma Technology Ltd., Morton Grove, Ill. These small portable devices, likewise only have unidirectional flow, with the attendant problem of buildup of large dust particles impeding the unidirectional flow through the HEPA filter.
- As, used herein this application, “HEPA” filter and/or “HEPA” filter material includes the true HEPA filter and/or true HEPA filter material (or a filter and/or filter material tested by methods equivalent to MIL-STD-282, Method 102.9.1), as well as, the ASHRAE HEPA filter and/or ASHRAE HEPA filter material (or a filter and/or filter material tested by methods equivalent to ASHRAE Standard 52.1-1992).
- Typically, to provide the air cleaning, source control and ventilation at least two units/devices are needed. This becomes expensive in terms of costs of the devices and maintance of the devices. Thus what is needed is a low cost device which provides incoming ventilation air which is both HEPA filtered and HEPA conditioned by heat and moisture exchange. Not withstanding the many known practical design problems for air-to-air heat exchangers with air filtration, the art has not responded to date with the production of a compact, lighter weight, air-to-air heat recovery ventilator using a regenerative heat exchanger made of pleated HEPA filter material and not requiring any heater to heat incoming air to avoid freeze-up problems in the heat recovery ventilator, and also not requiring complex rotating seals in the regenerative heat exchanger between an indoor climate and an outdoor climate.
- The present invention provides an integrated heat recovery ventilator HEPA filter utilizing air-to-air regenerative heat exchangers made of pleated HEPA filter material and utilizing a fully rotating air switch. The heat recovery ventilator comprises four rectangular regenerative heat exchangers, two blowers, a rotating air switch all disposed in a compact rectangular housing. The regenerative heat exchangers are made of a pleated HEPA filter material. The HEPA filter (HEPA filter material) captures at least 99.97% of particles having a particle diameter of 0.3 microns. Alternatively the HEPA filter (HEPA filter material) is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure. The regenerative heat exchangers preferably have a pleat density of 6 pleats per inch. The regenerative heat exchangers are stationary with stationary seals between the outside and inside climate. One of the blowers blows a stale airstream out through the heat exchangers; the other blower blows the fresh airstream in through the heat exchangers. The rotating air switch operates in conjunction with the two blowers producing the necessary flow reversal through each regenerative heat exchanger to allow heat and moisture exchange between the stale airstream and the fresh airstream. The rotating air switch is disposed completely on the inside (indoor) climate side of the regenerative heat exchangers preventing freeze up in cold weather. The rotating air switch uses clearance seals. The system of the present invention provides a high performance, low cost, compact, lighter weight air-to-air heat recovery ventilator using a regenerative heat exchanger made of a pleated HEPA filter material and does not require any heater to heat incoming air and provides filtered incoming air as well as filtered outgoing air.
- The present invention utilizes a pleated HEPA filter material as the regenerative heat exchanger and advantageously provides high quality ventilation air which is both filtered and conditioned by heat and moisture exchange.
- It is an advantage of the present invention to provide a self cleaning regenerative heat exchanger, where the reciprocating airflow through the regenerative heat exchangers prevents the buildup of large dust particles in the HEPA filter material in the regenerative heat exchangers.
- It is another advantage of the present invention that the air flow balance is maintained as the HEPA filter material loads with particulates, allergens and/or pollutants. The flow imbalance is also advantageously maintained as the filters load. This imbalance can positively pressurize a leaky room with the HEPA filtered air creating a clean room effect.
- It is still another advantage of the present invention that the present invention is much more effective in cleaning the air in a room of external particulates, such as, pollen spores, diesel soot, etc., than using a standard console HEPA filter air cleaning device in the room. A tight room with the present invention delivering both filtered and heat and moisture exchange ventillation air is much cleaner (e.g., the indoor air in that room is cleaner), than a leaky room utilizing a standard console HEPA air cleaning device, providing filtration alone, to clean the indoor air in the leaky room. The term “tight room”, herein throughout, means a room having an air leakage of less than 0.1 air exchanges per hour (ACH) into the room. The term, “leaky room”, herein throughout, means a room with an air leakage of greater than 0.35 ACH or 15 cubic feet per minute (CFM) of air change per room occupant into the room. With the present invention, the room can be completely sealed from the outside, except for the ample supply of HEPA filtered and conditioned fresh air from the ventilator itself. In this instance, the indoor concentration of an external airborne particulate will be no greater than 0.03% of the outdoor level using true HEPA filters.
- It is yet another advantage that the present invention is more economical to produce, purchase and maintain.
- The foregoing, and other advantages of the present invention, are realized in one aspect thereof in a heat recovery ventilator for use in ventilating a room, or the like, having means for venting a stale airstream of an indoor climate to the outside air, means for supplying a fresh airstream from the outside air of an outside climate, at least two stationary regenerative heat exchangers made of pleated HEPA filter material and a rotating air switch for transferring the stale airstream to the regenerative heat exchangers from the means for venting the stale airstream of the indoor climate and for transferring the fresh airstream of the outside climate from the regenerative heat exchangers to the means for supplying a fresh airstream from the outside air of the outside climate, the rotating air switch being rotatably mounted and comprising a first circular side plate having an air flow opening therein, a second circular side plate having a pair of air flow openings with the second plate spaced apart and disposed opposed and parallel to the first side plate, and a single manifold. The manifold extends from the air flow opening in the first side plate to one of the pair of the air flow openings in the second side plate. The manifold encloses the air opening in the first side plate and one of the pair of air flow openings in the second side plate and forms a passage way for moving the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate. The other opening in the second side plate forms a stale air passageway for transferring the stale airstream from the means for venting the stale airstream of the indoor climate to the regenerative heat exchangers, such that air flows in opposite directions through the same regenerative heat exchanger. The air switch is isolated from the outside climate by the regenerative heat exchangers. The heat recovery ventilator further comprises a plurality of noncontacting clearance seals with one of the noncontacting clearance seals disposed between the first circular plate of the rotating air switch and both the means for venting the stale airstream and the means for transferring the fresh airstream, and the remaining noncontacting clearance seals disposed between the second circular plate and the stationary regenerative heat exchangers. There are four regenerative heat exchangers. The pleated HEPA filter material has a pleat density of 6 pleats per inch. The HEPA filter material captures at least 99.97% of particles having a diameter of 0.3 microns. Alternatively, the HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
- In yet another aspect, the invention is a heat recovery ventilator for use in a room or the like, comprising a housing, two blowers, at least two stationary regenerative heat exchangers made of a pleated HEPA filter material, a shaft, a single rotating air switch, mounted on the shaft, a motor for driving the blowers and the shaft, with one of the blowers for forcing a stale airstream out of the room and the other of the blowers for forcing a fresh airstream into the room. The air switch, in use, alternately imparts the stale airstream from one blower to a regenerative heat exchanger, then imparts the fresh airstream to that same heat exchanger and through the other blower, when the air switch rotates in a 180° turn. The rotating air switch of the heat recovery ventilator air switch has a first side plate having an opening and having a center shaft aperture, a second side plate having two openings spaced from each other, and a center shaft aperture, a single manifold extending from the first side plate to the second side plate, wherein the manifold connects the opening of first side plate with one of the openings in said second side plate forming a fresh air passageway, and a shaft receiving portion extending from the first side plate to the second side plate; wherein the rotating switch is disposed upon the shaft. The shaft is disposed in the shaft receiving portion. The HEPA filter material captures at least 99.97% of particles having a diameter of 0.3 microns. Alternatively, the HEPA filter material is rated at least 85% Dust-Spot Efficiency Percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
- In use, the fresh airstream flows from the regenerative heat exchangers through the fresh air passageway and is forced out by the other blower. The second opening of the second side plate along with a portion of the manifold and a portion of the shaft receiving portion form a stale air passageway from the one blower to the regenerative heat exchangers, for transferring the stale airstream to the regenerative heat exchangers. The housing of the aforementioned heat recovery ventilator has first compartment containing the one blower, a second compartment containing the other blower, a third compartment containing the rotating air switch, and a fourth compartment containing the regenerative heat exchangers. The first compartment has a plurality of openings therein for forcing the stale airstream to flow into the housing and through the blower. The second compartment has a plurality of openings therein for permitting the fresh airstream to exit the housing and to enter the room. The fourth compartment has a plurality of openings therein for forcing the stale airstream out of the fourth compartment and for allowing the fresh airstream to be drawn into the fourth compartment.
- The first compartment is next to the second compartment and shares a common blower bulkhead. The third compartment is adjacent to both the first compartment and the second compartment and shares a common motor bulkhead with the first compartment and the second compartment. The motor bulkhead has a first opening into the first compartment and a second opening into the second compartment. The fourth compartment is spaced from the first and second compartments and is adjacent to the third compartment. The fourth compartment shares a common regenerator bulkhead with the third compartment. The regenerator bulkhead has an opening therein. The rotating air switch is disposed in the third compartment with one end of the rotating air switch adjacent the opening in the regenerator bulkhead and the other end of the rotating air switch adjacent the opening in the motor bulkhead between the second and third compartments.
- In yet another aspect, the invention provides a method of providing indoor ventilation, air filtration and air pollution source control using a heat recovery ventilator having stationary rectangular regenerative heat exchangers, a manifold for accepting the regenerative heat exchangers, two blowers, one rotating air switch, a motor for driving the blower and air switch, all disposed in a housing, the housing having stale air openings for allowing a stale airstream to enter the housing and fresh air openings for allowing a filtered fresh airstream to exit from the housing. The method comprising the steps of: (a) selecting at least two stationary rectangular regenerative heat exchangers made of a pleated HEPA filter material, (b) disposing the stationary rectangular regenerative heat exchangers in the manifold, (c) forcing a stale airstream from an indoor climate into the housing, (d) blowing the stale airstream into the rotating air switch, (e) transporting the stale airstream from the rotating air switch into the stationary rectangular regenerative heat exchangers, (f) simultaneously exchanging heat and moisture from the stale airstream onto the regenerative heat exchangers, filtering the stale airstream, and forcing the filtered stale airstream to flow out of the housing, (g) forcing a fresh airstream into the housing and through the same regenerative heat exchangers, (h) exchanging heat and moisture on the regenerative heat exchanger into the fresh airstream and simultaneously filtering the fresh airstream, (i) forcing the filtered fresh airstream, which is heated and moisturized, into the rotating air switch and through the fresh air blower, and (j) forcing the filtered fresh airstream which is heated and moisturized out of the housing and into the indoor climate. The rotating air switch used in the present method includes a first side plate having an opening and having a center shaft aperture, a second side plate having two openings spaced from each other, and a center shaft aperture, a shaft receiving portion extends from the first side plate to the second side plate and connects the center shaft apertures, a single manifold extends from the first side plate to the second side plate. The manifold connects the first side plate opening with one of the openings in the second side plate and forms a fresh air passageway there between, while the other opening of the second side plate along with a portion of the manifold and a portion of the shaft receiving portion form a stale air passageway from the first blower to the regenerative heat exchanger. The method further comprises in step (d) blowing the stale airstream into the stale air passageway, in step (e) transporting the stale airstream from the stale air passageway in the rotating air switch into the stationary regenerative heat exchangers, and in step (i) forcing the filtered fresh airstream into the fresh air passageway in the rotating air switch and through the fresh air blower. The selecting step(a) includes selecting the pleated HEPA filter material wherein the HEPA filter material captures at least 99.97% of particles having a diameter of 0.3 microns. Alternatively the selecting step (a) includes selecting the pleated HEPA filter material wherein the HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
- In yet still another aspect, the present invention provides a method of providing indoor ventillation, air filtration and air pollution source control using a heat recovery ventilator having means for venting a stale airstream of an indoor climate to the outside air, means for supplying a fresh airstream from the outside air of an outside climate, and a regenerative heat exchanger. The method comprises the steps of: (a) selecting a regenerative heat exchanger of a pleated HEPA filter material, (b) positioning the regenerative heat exchanger in a stationary position to intercept a fresh air stream and to intercept a stale air stream; (c) venting the stale airstream from an indoor climate into the ventilator and into the regenerative heat exchanger with the means for venting the stale airstream of an indoor climate to the outside air; (d) simultaneously exchanging heat and moisture from the stale airstream onto the regenerative heat exchanger, filtering the stale air stream, and forcing the filtered stale airstream to flow out of the ventilator, (e) supplying fresh air into the ventilator and through the same regenerative heat exchanger with the means for supplying the fresh air stream from the outside air of an outside climate, (f) exchanging heat and moisture on the regenerative heat exchanger into the fresh airstream and simultaneously filtering the fresh airstream, and (g) forcing the fresh filtered airstream, which is heated and moisturized, out of the ventilator and into the indoor climate. The selecting step (a) includes selecting the pleated HEPA filter material wherein the HEPA filter material captures at least 99.97% of particles having a diameter of 0.3 microns. Alternatively, the selecting step (a) includes selecting the HEPA filter material, wherein the HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
- In yet a still further aspect, the present invention provides a convertible device which converts between a heat recovery ventilator providing filtered, heat and moisture conditioned air and an air filtration device providing filtered air. The convertible device comprises means for venting a stale airstream of an indoor climate to the outside air; means for supplying a fresh airstream from the outside air of an outside climate; at least two stationary regenerative heat exchangers made of a pleated HEPA filter material; and an air switch for transferring the stale airstream to the regenerative heat exchangers from the means for venting the stale airstream of the indoor climate and for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate. The air switch is rotatably mounted; wherein, the air switch is rotated when the convertible device is operated as a heat recovery ventilator and the air switch remains stationary when the convertible device is operated as an air filtration device. The HEPA filter material captures at least 99.97% of particles having a diameter of 0.3 microns. The HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
- Other advantages and a fuller appreciation of the specific attributes of this invention will be gained upon an examination of the following drawings, detailed description of preferred embodiments, and appended claims. It is expressly understood that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention.
- The preferred exemplary embodiment of the present invention will hereinafter be described in conjunction with the appended drawing wherein like designations refer to like elements throughout:
- FIG. 1 is a perspective view of a first embodiment of heat recovery ventilator of the present invention, seen from within the room of the structure, and with phantom lines showing the present invention positioned in a window, opening to the outdoor climate;
- FIG. 2 is a partially exploded view of the device of FIG. 1 rotated 180°;
- FIG. 3 is an enlarged perspective view of the lower casing and assembled compartments of FIG. 2 from the opposite direction with the regenerative heat exchangers and filter stops removed from the regenerator manifolds;
- FIG. 4 is an exploded enlarged perspective view of the bulkheads of the present invention;
- FIG. 5 is an enlarged perspective view of the rotating air switch of the present invention as seen from one side;
- FIG. 6 is a view of the rotating air switch of FIG. 5, as seen from the other side;
- FIG. 7 is a top schematic view of the device of FIG. 1 illustrating the interior of the four compartments comprising the present invention, with upper casing top wall, a portion of the exterior cover, and a portion of the sealing material removed and with the pleated folds of the regenerative heat exchanger shown schematically in hidden line;
- FIG. 8 is a front view of the exterior side of the present invention with the exterior cover removed and with the regenerative heat exchangers, filter stops and sealing material removed, illustrating the travel of the rotating air switch through the regenerator manifolds;
- FIGS.9A-9D are, respectively, a perspective view, a rear view with the filter frame partially broken away to show the pleating of the HEPA filter material (the front view being a mirror image thereof), a bottom plan view (the top plan view being a mirror image thereof), and right side view (the left side view being a mirror image thereof) of the most preferred prior art pleated HEPA filter material heat exchanger for use in the device of FIG. 1, the pleats are shown in partial view on the bottom plan view;
- FIG. 9E is a perspective view of the preferred prior art pleated HEPA filter material without the frame around it, showing the accordian fashion pleating;
- FIG. 9F is a perspective view of a prior art pleated HEPA filter material heat exchanger for use in the device of FIG. 1, the heat exchanger being made without the glue beads as shown in FIG. 9A;
- FIG. 10 is a partial view of the preferred prior art HEPA filter material used in the preferred pleated HEPA regenerative heat exchanger of FIG. 9 before the HEPA filter material is pleated;
- FIG. 11 is a view of the exterior side, oriented as in FIG. 8 showing the arrangement of the stationary regenerative heat exchangers and filter stops, when the exterior cover and the sealing material are removed;
- FIG. 12A is an exploded enlarged view of the rotating air switch of FIG. 5;
- FIG. 12B is an exploded enlarged view of the rotating air switch of FIG. 5 illustrating an alternative pie shaped manifold;
- FIGS.13A-13D are schematic perspective views for the embodiment of FIG. 1 illustrating the fresh air flow and the stale air flow through the regenerator bulkheads containing the regenerative heat exchangers as the rotating air switch travels in a 360° full rotation, beginning with the position of the rotating air switch as shown in FIG. 8, with the regenerative heat exchangers, filter stops, sealing material and the exterior cover removed; and
- FIG. 14 is a partially exploded view of the present invention of FIG. 1 made with a plurality of compressible seals and made without filter stops and without a gasket.
- The present invention relates broadly to regenerative air-to-air heat exchangers, regenerative air-to-air enthalpy exchangers, and HEPA filters. The invention is particularly well-suited for air-to-air regenerative heat exchangers utilizing high efficiency particulate air (HEPA) filter material as the regenerative heat exchanger. Applicants' copending application U.S. application Ser. No. 08/893,833 filed Jul. 11, 1997, discloses an integrated heat recovery ventilator (HRV) using regenerative heat exchangers and a separate HEPA filter assembly disposed in an interior cover. Also disclosed in that application is an integrated heat recovery ventilator utilizing regenerative heat exchangers without the separate HEPA filter assembly and without the interior cover. Applicants disclose that other regenerative heat exchangers may be used in the invention of U.S. application Ser. No. 08/893,833, Page 30, lines 6-15, which disclosure, Applicants hereby incorporate by reference.
- This present application discloses a new embodiment of the HRV without the separate HEPA filter assembly in the interior cover and without the interior cover, but utilizing a pleated HEPA filter material regenerative heat exchanger. FIGS.1-13D and FIG. 14 illustrate an integrated heat recovery ventilator (HRV) 100″ of the present invention using a pleated HEPA filter material
regenerative heat exchanger 102″. -
HRV 100″ is particularly well-suited for use in small to medium sized building structures such as homes, apartments, condominiums, restaurants, taverns, small shops, and rooms thereof, etc. It is particularly well suited for home heath care applications where the individual(s) dwelling in the building structure are suffering from respiratory problems and who may be suffering from lungs diseases, asthma or allergies. TheHRV 100″ is also suitable for the hospital isolation ward where both the outgoing air and the incoming air must be filtered. - The general construction of
HRV 100″ preferably utilizes four identically dimensioned and constructed HEPA filter materialregenerative heat exchangers 102″, respectively 102″A, 102″B, 102″C, 102″D. Theregenerative heat exchangers 102″A-102″D each have aheat exchange matrix 104″A-104″D, respectively. Eachheat exchange matrix 104″A-104″D is made of a pleated HEPA filter material which is a heat exchanger material in which heat and moisture exchange occurs. HEPA filter material and the pleated HEPA filter construction is well known prior art as has been discussed in detail in the background of the invention. Although the present invention will work with any type of HEPA filter, the ASHRAE HEPA represents the lower range of the preferred quality of HEPA filters and HEPA filter materials for the present invention. The true HEPA is the most preferred HEPA filter and most preferred HEPA filter material for the present invention. As is known in the prior art, and shown in FIGS. 9A-9F and 10, a band (strip) 101 ofHEPA filter material 103 is folded upon itself in accordion fashion, forming a plurality of uniform dimensionedpleats 105 to form afilter pack 107. Eachpleat 105 has a pleat edge (or fold line) 105′. Thefilter pack 107 of pleated HEPA filter material is fastened, preferably glued into a rectangularperipheral frame 109, forming each of the HEPA filter materialregenerative heat exchangers 102″, which may be any one ofregenerative heat exchangers 102″A-102″D. - The
frame 109 can be made of cardboard, chipboard, plastic or other lightweight materials, as is known in the art. As best shown in FIGS. 9E and 10, one or more glue beads 111 (a small band of glue material) may be disposed on one side or both sides of theband 101. Theband 101 is accordion pleated, folded upon itself. As the glue beads 111 solidify, they form spacers 113 betweenadjacent pleats 105, giving additional rigidity to thefilter pack 107. Alternatively, as shown in FIG. 9F, the glue beads 111 may be omitted and theband 101 accordion pleated and glued into the rectangularperipheral frame 109 formingregenerative heat exchanger 102″. In FIGS. 9A-9D, and 9F, thepleats 105 are shown in a vertical orientation; alternatively, thepleats 105 may be disposed in a horizontal orientation. The HEPA filter material of the present invention includes, but is not limited to, the true HEPA filter material, the ASRAE HEPA filter material, as well as, their equivalents. The present invention preferably uses HEPA filter (HEPA filter material) rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure. The present invention most preferably utilizes a HEPA filter (HEPA filter material) which captures 99.97% of all particles of 0.3 microns in diameter which pass through it. - Referring to FIG. 2, the
regenerative heat exchangers 102″A-102″D, each also have a respective outside side or face 106″A-106″D, formed by the plurality of pleat edges 105′, which face the outside climate, e.g., the outside outdoor fresh air, and a respective opposite inside side or face 108″A-108″D, formed by the plurality of opposite pleat edges 105′, facing the inside (indoor) climate, e.g., the indoor stale air of a room. Theregenerative heat exchangers 102″A-102″D are stationary with a stationary seal(s) 354 between theoutside climate side 106″A-106″D and insideclimate side 108″A-108″D. -
HRV 100″ includes twoblowers blower 112 blows stale air out of the structure through theregenerative heat exchangers 102″A-102″D. Blower 114 blows fresh outdoor air in through theregenerative heat exchangers 102″A-102″D. Since theregenerative heat exchangers 102″A-102″D are “regenerative”, stale air flows out of any one of them for a finite period of time when the flow is reversed and fresh air flows in the opposite direction. This flow pattern is also said to be “reciprocating”. In this way, heat and moisture in the stale air, which is deposited on theheat exchange matrix 104″A-104″D, is imparted to the cold dry fresh air. - Also since the material of the
heat exchanger matrix 104″A-104″D is a HEPA filter material, the fresh air bearing allergens, particulates and pollutants is filtered through theregenerative heat exchangers 102″A-102″D, bringing fresh filtered air into theHRV 100″ and discharging filtered stale air out of theHRV 100″. This is especially useful in the hospital isolation ward where both the outgoing stale air and the incoming fresh air must be filtered. It is also very beneficial in home health care applications for individuals suffering from respiratory illnesses, asthma or allergies. Thus source control, as well as ventilation, are advantageously achieved without the need for a separate HEPA filter on the HRV as disclosed in applicants' application Ser. No. 08/893,833 or for a standard console HEPA filter air cleaning device. As the stale air flows through the HEPA filter material in theregenerative heat exchanger 102″A-102″D certain indoor pollutants, allergens and particulates are trapped in the filter, thereby cleaning the indoor air. The filter loads with very small particles. It is believed that the fine dust particles and other very small particles are captured by the HEPA filter material and held onto it by van der Waal forces. - Also the reciprocating flow provides self cleaning action of the
regenerative heat exchanger 102″A-102″D. The reciprocating flow prevents build up of large dust particles, which typically impede airflow in a standard unidirectional air flow device, such as a standard console HEPA air cleaning device. In unidirectional air flow devices, it is not uncommon for users of the devices to extend the life of the HEPA filter by vacuuming the larger dust particles off the HEPA filter. Alternatively, some devices have a pre-filter element fabricated of a less expensive material than HEPA filter material. The pre-filter element is used to trap these larger dust particles, before the air is conducted into the HEPA filter. Advantageously, the reciprocating flow allows the HEPA filter materialregenerative heat exchangers 102″A-102″D to last longer because the HEPA filter material is not being loaded with the larger particles. This advantage means no pre-filter is needed, as is sometimes needed on standard console HEPA air cleaning devices and that less maintenance is required to keep theHRV 100″ operational over an extended period of time. - Thus the present invention is more economical to build (manufacture), purchase and operate. This is because separate HEPA filters (or other air cleaning devices) to post-clean the ventillation air of pollen, mold spores, etc., in addition to the regenerative heat exchangers are not required, and because the HEPA filter material
regenerative heat exchangers 102″A-102″D of the present invention last longer because they do not plug up (load) as easily with large dust particles because of the reciprocating flow. - In addition, air flow balance is advantageously maintained between the fresh air stream and the stale air stream as the HEPA filter material
regenerative heat exchangers 102″A-102″D of the present invention load. This maintance of air flow balance occurs because resistance to the air flow should be independent of air flow direction, as the HEPA filter material of theregenerative heat exchangers 102″A-102″D load with particles. - Air flow imbalance is also maintained as the HEPA material
regenerative heat exchangers 102″A-102″D of the present invention load. Air flow imbalance is caused by one of the two aforementioned airstreams. having a larger flow resistance, or one of the twoblowers HRV 100″ through which stale air enters into theHRV 100″. The entrance of stale air into theHRV 100″ will be described later, when the operation of theHRV 100″ is explained. - A separate
rotating air switch 116 operating in conjunction withblowers blower 112 is a stale air blower andblower 114 is a fresh air blower. A conventional commerciallyavailable gear motor 117 drives therotating air switch 116. Thegear motor 117 is an assembly combining both a conventional electric motor (not shown) and a gear box (not shown). Therotating air switch 116 is located completely on the inside (indoor)climate side 108″A-108″D of theregenerative heat exchangers 102″A-102″D and thus isolated from the outside climate. Advantageously, this unique location of therotating air switch 116, plus the use ofregenerative heat exchangers 102″A-102″D in theHRV 100″ prevents the possibility of freeze-up of therotating air switch 116 in cold weather. Also, the rotatingair switch 116 preferably uses noncontacting clearance seals 118, 119, thus there is no wear problem. A conventionalelectric motor 120 is used to operate theblowers HRV 100″. Suitable conventionalelectrical components 121 are used to convey electrical power to the device. A compact rectangular cover orhousing 122 encloses the rectangularregenerative heat exchangers 102″A-102″D, the stationary seal(s) 354, thestale air blower 112, thefresh air blower 114, the rotatingair switch 116, thegear motor 117, the clearance seals 118, 119, and theelectrical motor 120. - Reference is now made specifically to FIG. 1, wherein the integrated
heat recovery ventilator 100″ is shown mounted in awindow opening 124 in a room of astructure 126. Thewindow opening 124 and room ofstructure 126 are illustrated in phantom lines. FIG. 1 showsHRV 100″ of the present invention as viewed from the interior of the room in which the invention is used. As used herein, “interior” refers to that side of theHRV 100″ which typically faces the interior (indoor side) of the structure being ventilated, and outside or “exterior” refers to that side of theHRV 100″ which typically faces the outside of thestructure 126 being ventilated (outdoor climate).HRV 100″ may be mounted in awindow 124 or through an opening in an exterior wall (not shown) of a room of astructure 126. - Also the
HRV 100″ may be removed from thewindow 124, and placed in the room of thestructure 126 and used as a standard console HEPA filter air cleaning device as will be explained later. - As best shown in FIGS. 1 and 2, the
rectangular housing 122 ofHRV 100″ has three housing portions: anupper casing 130, alower casing 132, and an “exterior”cover 136 which are fastened together. -
Upper casing 130 has a generally rectangulartop wall 138 and three downwardly dependingside walls Side walls Side walls side wall 141 extending betweenside walls Top openings 150 are disposed on thetop wall 138 of theupper casing 130.Side openings 152 are disposed on theside wall 140 near thetop openings 150. Anupper casing window 154 is disposed inside wall 141.Window 154 is sealed with aclear plastic piece 156. - The
lower casing 132 has abottom wall 160 and threeside walls bottom wall 160. Theside walls ledge 168. Alip 169 extends upwardly from theledge 168.Side walls side wall 164 extending between them and generally perpendicular to them.Side walls upper casing 130 to rest on theledge 168 above each and abut againstlip 169.Openings 170 are suitably arranged on theside walls lip 169 aboveside walls upper casing 130 to thelower casing 132 usingconventional fasteners 172, such as hardware screws. As is best shown in FIG. 3,side openings 174 are disposed in theside wall 162. The mounting of theHRV 100″ in an opening or thewindow 124 in the room of thestructure 126 must allow theside openings top openings 150 to be physically inside thestructure 126. Preferablyopenings -
Openings 175 are disposed inside wall 164 nearside wall 166.Proximate openings 175. is alower casing window 177 which is sealed with aclear plastic piece 179. Thewindow 154 is disposed directly above thewindow 177 when theupper casing 130 is attached to thelower casing 132. Preferablyopenings 175 are louvered openings with alouver 175′ directed upwardly to channel air toward the ceiling of a room in which thedevice HRV 100″ is used. When thedevice HRV 100″ is operated without an automatic frost protection or a defrost cycle, one may check for any frost or dirt build-up occurring on theregenerative heat exchangers 102″A-102″D by viewing them throughwindows windows HRV 100″ is working properly. - The
lower casing 132 contains thestale air blower 112, thefresh air blower 114, themotor 120 for controllingblowers air switch 116, thegear motor 117, conventional electronics for driving the gear motor (not shown), miscellaneous wiring for themotors blowers air switch 116, amotor bulkhead 176, aregenerator bulkhead 178, ablower bulkhead 180, a plurality ofregenerator manifolds 182A-182D and an equal number ofregenerative heat exchangers 102″A-102″D. - As shown in FIG. 3, the
lower casing 132 is divided into four large compartment sections. Afirst section 181 and asecond section 183 are created by the arrangement of theblower bulkhead 180 and themotor bulkhead 176. Theblower bulkhead 180 is disposed between thefresh air blower 114 and thestale air blower 112 and serves to isolate each blower from the other. Themotor 120 and means for driving thegear motor 117 are suitably adjacent to thefresh air blower 114 and on the same side of theblower bulkhead 180 as thefresh air blower 114. Themotor bulkhead 176 is disposed generally parallel toside wall 164 and in contact withblower bulkhead 180. Thus, thefirst compartment section 181 contains thefresh air blower 114,motor 120, and means for driving the gear motor, and thesecond section 183 contains thestale air blower 112. Themotor bulkhead 176 has a largecircular opening 184 adjacent to and almost abutting aside plate 260 of therotating switch 116 and a separatestale air opening 186 for communicating with thestale air blower 112. Thecircular opening 184 is disposed to communicate with thefresh air blower 114. Abaffle 187 sealingly connectsstale air blower 112 tostale air opening 186 in themotor bulkhead 176.Circular opening 184 is preferably smaller in diameter than diameter ofside plate 260. - The
regenerator bulkhead 178 is spaced from themotor bulkhead 176 and is oriented generally parallel to it forming athird compartment section 191. Thethird compartment section 191 is sufficiently dimensioned to permit the interposition of therotating air switch 116 betweenmotor bulkhead 176 and theregenerator bulkhead 178. Theregenerator bulkhead 178 has a largecircular opening 188 adjacent to and almost abutting anopposite side plate 262 of therotating air switch 116.Circular opening 188 is preferably smaller in diameter than diameter ofside plate 262.Circular openings side plates gear motor 117 for driving therotating air switch 116 is also disposed in thethird section 191. - A
fourth compartment section 193 defines the space occupied by theregenerator manifolds 182A-182D on the side of theregenerator bulkhead 178 opposite therotary air switch 116. The interrelation of these elements of theHRV 100″, will be discussed after the discussion of theexterior cover 136. - The
motor bulkhead 176, theregenerator bulkhead 178, and theblower bulkhead 180 are suitably dimensioned to contact thetop wall 138 when theupper casing 130 is fastened to thelower casing 132. Preferably, themotor bulkhead 176 and theregenerator bulkhead 178 each haveflanges top wall 138 when theupper casing 130 andlower casing 132 are fastened. - The final part of the
housing 122 ofHRV 100″ is theexterior cover 136, as best shown in FIG. 2. Theexterior cover 136 has a generallyrectangular surface 206 having a plurality ofopenings 208 for air flow therein. Preferablyopenings 208 are louvered having a downwardly directedlouver 208′ to prevent rain and snow from entering theexterior cover 136. Theexterior cover surface 206 has fouredges rectangular sides stationary seal 354 is acompressible sealing material 355, having a plurality ofopenings 356 therein, which is inserted in theexterior cover 136. Theexterior cover 136 is suitably dimensioned to fit over the adjoinedupper casing 130 andlower casing 132. Thesides side walls upper casing 130 each havesuitable openings 226 to permitopenings 226 to align when theHRV 100″ is assembled.Suitable fasteners 228 may be threaded through theopenings 226 to fasten theexterior cover 136 to the joinedupper casing 130 andlower casing 132. Thesefasteners 228, include but are not limited to, hardware screws. - As best shown in FIGS.1-3 and 7, when the three portions of the
housing 122 forHRV 100″ are fully assembled, the housing forms four compartments. Afirst compartment 230 is formed by upper casingtop wall 138, uppercasing side wall 140, uppercasing side wall 141, lowercasing bottom wall 160, lower casing upwardlyside walls motor bulkhead 176, andblower bulkhead 180. Thefirst compartment 230 contains thestale air blower 112. Theopenings openings HRV 100″, one can create air flow imbalance between the fresh air stream and the stale air stream which can positively pressurize a leaky room to achieve a clean room effect. A clean room effect herein throughout means a room in which all the air entering the room passes through a HEPA filter. - A
second compartment 232 is formed by the upper casingtop wall 138, uppercasing side walls blower bulkhead 180,motor bulkhead 176, lowercasing side walls casing bottom wall 160. Thissecond compartment 232 contains thefresh air blower 114,motor 120, and means for driving theair switch 116 with thegear motor 117. Theopenings 175 insidewall 164 provide fresh filtered air flow out of this compartment.Covered windows - A
third compartment 234 is formed by the upper casingtop wall 138, uppercasing side walls casing bottom wall 160, lowercasing side walls motor bulkhead 176, andregenerator bulkhead 178. Thisthird compartment 234 contains the rotatingair switch 116 and thegear motor 117. - A
fourth compartment 236 is formed byregenerator bulkhead 178, upper casingtop wall 138, uppercasing side walls casing bottom wall 160, lowercasing side walls exterior cover 136. The forth compartment contains theregenerator manifolds 182A-182D and theregenerative heat exchangers 102″A-102″D and the sealingmaterial 354. Theopenings 208 inexterior cover 136 and theopenings 356 in theseal material 354 permit fresh air flow into theregenerative heat exchangers 102″A-102″D and stale air to flow out of theregenerative heat exchangers 102″A-102″D. - The air flow is generally balanced as the
regenerative heat exchangers 102″A-102″D load with pollutants, allergens and particulates. - As is known in the art, conventional electrical switches and wiring (not shown) are used in the
HRV 100″. TheHRV 100″ has a continuously variable blower (high speed/low speed)switch 242 which also serves as an on-off switch for both theblower motor 120 and thegear motor 117, which drives therotating air switch 116. Hereinafter theswitch 242 is also referred to as the on-off switch 242. Another switch, agear motor switch 244, with its associated conventional wiring (not shown) is optional and is used to just turn off and on thegear motor 117. When thegear motor switch 244 is present on the device, theHRV 100″ may be operated as a convertible device, permitting theHRV 100″ to be operated as a standard HEPA filter air filtration device, or as standard console HEPA air filtration device to filter indoor room air. The presence of thegear motor switch 244 enables one to use theHRV 100″ as a convertible device. The use of the optionalgear motor switch 244 will be explained subsequently and in respect to Examples 2 & 3. - A conventional
electrical cord 246 with aplug 248 provides electricity to operate themotors HRV 100″ when theHRV 100″ is energized with electricity. Automatic defrost can be added to theHRV 100″ by placing a thermometer (not shown) to sense outside temperature. When the outside temperature gets low enough, appropriate conventional electronics can be used to turn thegear motor 117 on and off continuously, such that therotating air switch 116 rotates half a turn (e.g., 180°); stops for a period of time; rotates half a turn in the same direction, (e.g., 180°); stops; etc. This reduces the effectiveness of the heat exchange which, in turn, reduces the temperature at which frost sets in. As outside temperature decreases, the period of time, during which thegear motor 117 stops, can be increased. - The present invention is operated in the following way. The electrical cord is plugged into a conventional electrical outlet. The on-
off switch 242 is activated. This activates themotor 120.Gear motor 117 is also activated at this time. Stale air enters theHRV 100″ through theside openings top openings 150 of thehousing 122 and is drawn into thefirst compartment 230 by thestale air blower 112. Thus, the stale air from the indoor climate of thestructure 126 is forced into thehousing 122 and forms a stale airstream. - The
fresh air blower 114 and thestale air blower 112 are driven by thesingle motor 120. Thestale air blower 112 blows the stale air through theopening 186 in themotor bulkhead 176 into thethird compartment 234, e.g., the space between themotor bulkhead 176 and theregenerator bulkhead 178. The stale airstream flows into therotating air switch 116. Therotating air switch 116 transports the stale airstream from thethird compartment 234 into the stationaryregenerative heat exchangers 102″A-102″D in thefourth compartment 236. - The rotating
air switch 116, as best shown in FIGS. 5, 6, 12A and 12B is comprised of two circular side plates and a manifold extending there between. The two circular side plates are amotor side plate 260 and aregenerator side plate 262. Preferably, themotor side plate 260 and theregenerator side plate 262 are identical in circular dimension and spaced parallel to each other. In the preferred embodiment, themotor side plate 260 is dimensioned to be larger than thecircular opening 184 in themotor bulkhead 176. Likewise, theregenerator side plate 262 is dimensioned to be larger than thecircular opening 188 in theregenerator bulkhead 178. Themotor side plate 260 and theregenerator side plate 262 are approximately 8% larger in diameter than the correspondingcircular opening respective bulkheads motor side plate 260 and theregenerator side plate 262 each have outer diameters of about 7 inches; where as, thecircular openings circular openings side plates circular openings clearance seal 118 is a small air gap between themotor side plate 260 and thebulkhead 176. Theclearance seal 119 is a small air gap between theregenerator side plate 262 and thebulkhead 178. Thus, thebulkheads respective side plates rotating air switch 116. In the preferred embodiment, thebulkheads housing 122 and therotating air switch 116 is slipped between thebulkheads Side plate 260 is adjacent to and in almost abutting relationship withbulkhead 176. The clearance seals 118, 119 are air gaps of approximately 0.015 inches and prevent full contact of theside plates respective bulkheads Side plate 262 is adjacent to and in almost abutting relationship withbulkhead 178. - The rotating
air switch 116, may be mounted in theHRV 100″ in an alternate manner as may be appreciated by those skilled in the art. In this alternative mounting schema all other aspects of theHRV 100″ are identical, except as described subsequently. In this alternative mounting schema, themotor side plate 260 is dimensioned to fit within thecircular opening 184 in themotor bulkhead 176 to allow rotation of therotating air switch 116 within theopening 184. Theregenerator side plate 262 is dimensioned to fit within thecircular opening 188 in theregenerator bulkhead 178 to allow rotation of therotating air switch 116 within theopening 188. The clearance seals, 118, 119 are preferably noncontacting clearance seals, e.g, air gaps. In this embodiment noncontacting clearance seals 118, 119 are rim seals, e.g. small gaps between the circumference of the circular openings, 188,184 and therespective side plate clearance seal 118 between theopening 184 and themotor side plate 260 prevents scraping of therotating air switch 116 against thecircular opening 184 while sealing air flow. Theclearance seal 119 between theopening 188 and theregenerator side plate 262 prevents scraping of therotating air switch 116 against thecircular opening 188 while sealing air flow. In this alternative mounting schema, aside plate rotating air switch 116 is placed into the correspondingopenings bulkhead other bulkhead other opening other side plate rotating air switch 116. The clearance seals (rim seals) 118, 119 are air gaps of approximately 0.015 inches and prevent full contact of theside plates respective bulkheads - In either way of mounting the
rotating air switch 116, themotor side plate 260 has a single air switch motorside plate opening 270. Preferably motor side plate opening 270 is a quarter circle (e.g., subtends an angle of approximately 90°), pie shaped opening. As is used herein throughout, “pie shaped” refers to a shape bounded on two sides by concentric circular arcs of different radii and bounded on the other two sides by radial lines. Theregenerator side plate 262 has two air switch regeneratorside plate openings side plate openings circular side plates side plate openings 272. As best shown in FIGS. 5, 6, 12A and 12B, the manifold 276 has four major sides. These major sides are ashaft side portion 277, anopposite portion 278, afirst side portion 279 and asecond side portion 280. Thefirst side portion 279 extends between theportion 277 andopposite portion 278. Thesecond side portion 280 is disposed shaft side oppositeportion 279 and connectsportion 277 andportion 278. Preferably, as best shown in FIG. 12A, theshaft side portion 277 is a small planar portion extending betweenfirst side portion 279 andsecond side portion 280. Oppositeportion 279 is a large circular arc portion smaller in outer radius than theside plates - Alternatively, as best shown in FIG. 12B, the manifold276 is pie shaped. Thus the
shaft side portion 277 is a small circular arc curved portion extending betweenfirst side portion 279 andsecond side portion 280, and theopposite portion 278 is a large circular arc portion concentric with theshaft side portion 277. Oppositeportion 278 is smaller in outer radius thanside plates - As shown in FIGS. 5, 6,12A and 12B, the
manifold portions rotating air switch 116, collectively form a fresh air passageway in the rotating air switch. - As best illustrated in FIGS. 12A and 12B, the three
portions circular arc portion 278 is also made of sheet metal and has a pair of sides or tabs 288 (partially shown in phantom lines). Thesides 288 are suitably bent and shaped so that they may be fastened to thefirst side portion 279 and to thesecond side portion 280. Thebent sides 288 provide additional strength to therotating air switch 116. Thesides 288 are preferably welded toside portions rotating air switch 116 is injection molded or cast, thetabs 288 are optional. - Each
side plate motor side plate 260 hascenter aperture 281; theregenerator side plate 262 hascenter aperture 282. The rotating air switch further has twobraces motor side plate 260 to theregenerator side plate 262. Thebraces side plates braces elongated rectangles 285 with anangled bend 286 running the length of therectangle 285. Thebend 286 preferably adds additional strength to each of thebraces sides braces sides opening 274. - The rotating air switch further has a
shaft receiving portion 287 extending from themotor side plate 260 to theregenerator side plate 262 and centered on thecenter apertures Center aperture 281 andcenter aperture 282 are centered with respect to each other and spaced in a generally parallel spaced relationship to each other. Theshaft side portion 277 ofmanifold 276 is adjacent to and preferably in contacting, e.g., abutting, relationship withshaft receiving portion 287. Ends ofshaft receiving portion 287 are preferably spot welded toside plates - The rotating
air switch 116 is mounted on ashaft 289, as is best shown in FIG. 7.Shaft 289 passes through thecenter apertures respective side plate shaft receiving portion 287. Therotating air switch 116 is driven in a conventional manner by thesmall gear motor 117 using convention means, e.g., through atiming belt 290 and twopulleys motor side plate 262 has asecond aperture 295 therein. Thesecond aperture 295 is suitably dimensioned for accepting a set screw (not shown) which is attached topulley 294. A hole (not shown) is drilled or tapped into thepulley 294 to accept the set screw. In this manner thepulley 294 is locked with therotating air switch 116. - The
gear motor 117 turnspulley 292 which drivestiming belt 290 which, in turn, drivespulley 294, forcing it to turn. Sincepulley 294 and therotating air switch 116 are locked and centered about thecommon shaft 289, the rotatingair switch 116 is forced to rotate. In operation theshaft 289 permits therotating air switch 116 full 360° continuous rotation. This arrangement advantageously simplifies the operation of the HRV as compared to the prior art devices utilizing periodic acute angled back/forth rotation. - The stale airstream, which is forced into the
third compartment 234 between the twobulkheads stale air blower 112, can only exit that region through the rotating air switch side plate opening 274, e.g., the opening not covered by themanifold 276. Effectively, a stale air passageway is created by the first andsecond side portions shaft receiving portion 287, and themotor side plate 260 andregenerative side plate 262. The stale airstream then flows through a portion of theopening 188 in theregenerator bulkhead 178 and into thefourth compartment 236, containing theregenerative heat exchangers 102″A-102″D. - The
regenerator bulkhead 178 has aninterior side 296 facing themotor bulkhead 176 and an oppositeexterior side 300 facing theregenerative heat exchangers 102″A-102″D. On theexterior side 300 of theregenerator bulkhead 178, there are four bulkheads which together with the casing andregenerator bulkhead 178 form the fourregenerator manifolds 182A-182D for holding theregenerative heat exchangers 102″A-102″D. There is preferably ahorizontal regenerator bulkhead 302; a centervertical bulkhead 304; a leftvertical bulkhead 306 and a rightvertical bulkhead 308. Fourrectangular manifolds 182A-182D with the same dimensions are thus formed, with thetop wall 138 of theupper casing 130 forming top walls of two of the regenerator manifolds (182A-182B) and thebottom wall 160 of thelower casing 132 forming bottom walls of the remaining two regenerator manifolds (182C-182D). Each of theregenerator manifolds 182A-182D has anidentical manifold width 312, anidentical manifold height 314 and anidentical manifold depth 316. Each of theregenerator manifolds 182A-182D hasvertical edges 309 corresponding to portions of thevertical bulkheads exterior cover 136 when therectangular housing 122 of theHRV 100″ is assembled. - Preferably a
filter stop 317 is slid onto eachvertical edge 309. Each identically dimensionedfilter stop 317 is preferably a generally “V”shaped rectangular member having avertex 319 and twosides 321 extending from thevertex 319. A generallyperpendicular lip 323 extends from eachside 321 of the “V”. Thevertex 319 of the “V” is slightly curved to accommodate a thickness of one of theedges 309. Thesides 321 of the filter stop 317 are spaced from each other at a distance sufficient to snugly engage against a respectivevertical bulkhead lips 323 are spaced at a distance from thevertex 319 of the “V” to correspond to the regenerativeheat exchanger depth 356. Thelips 323 from adjacent pairs of filter stops 317 function to limit the travel of the regenerative heat exchanger in the regenerator manifold. Preferably thefilter stop 317 is made of a lightweight flexible metal; most preferably filterstop 317 is made of 0.020 inch thick aluminum sheeting. - The four rectangular
regenerative heat exchangers 102″A-102″D are placed in the respectiverectangular regenerator manifolds 182A-182D. The travel of each of theregenerative heat exchangers 102″A-102″D toward theregenerator bulkhead 178 is limited by thelips 323 of adjacent pairs of filter stops 317. Theregenerative heat exchangers 102″A-102″D are identically dimensioned and constructed. FIGS. 9A-9D illustrate the detailed structure of a most preferred prior art pleated HEPA filter material regenerative heat exchanger labeled as 102″, which may be anyone ofregenerative heat exchangers 102″A-102″D. Alternatively, theregenerative heat exchangers 102″ shown in FIG. 9F may be used in the present invention and placed inmanifolds 182A-182D. These structures of the pleated HEPA filter materialregenerative heat exchanger 102″ (with and without the glue bead 111) have been previously described herein. - The preferred pleat density for the
regenerative heat exchanger 102″ (with or without the glue bead 111) is 6 or more pleats per inch, however a pleat density of 5 pleats per inch may be used. The upper range of the pleat density is a function of the thickness of the filter material (media), the depth of the pleating and whether or not a glue bead is used in providing rigidity to the filter. The pleat density is important because the total cross sectional area of filter material is proportional to the pleat density. The HEPA filter material has a high resistance to air flow, hence, a large cross sectional area is important for reasonable flow. The pleat density of 6 pleats per inch advantageously provides a cross section area of nearly 789 square inches of HEPA filter material per heat exchanger when constructed according to Example 1. - Each of the
regenerative heat exchangers 102″A-102″D has aheat exchanger width 350 and aheat exchanger height 352, and aheat exchanger depth 357, which are somewhat less than corresponding dimensions for themanifold width 312,manifold height 314, andmanifold depth 316.Stationary seals 354 are used with theregenerative heat exchanger 102″, to force air flow to go through theregenerative heat exchanger 102″ and not around. An example of preferredcompressible sealing material 355 of thestationary seal 354 is thecompressible foam gasket 355 having the plurality ofopenings 356 therethrough. Thefoam gasket 355 is suitably dimensioned to fit within theexterior cover 136. Thefoam gasket 355 is preferably a closed cell foam, commercially available from McMaster-Carr Supply Company, Chicago, Illinois, as FOAM-SEAL™ polyvinyl chloride(PVC) foam or insulmide polyimide foam. Thefoam gasket 355 is preferably cut of a sheet of ¼ inch to {fraction (3/16)} inch thick closed cell foam.Openings 356 are cut in thefoam gasket 355. Eachopening 356 in thefoam gasket 355 is suitably dimensioned to align withframe openings 110 on theregenerative heat exchangers 102″ when theregenerative heat exchangers 102″A-102″D are loaded into themanifolds 182A-182D and thehousing 122 is assembled. For the HEPAfilter heat exchanger 102″A-102″D, it is important to seal off air flow leaking around the filter in the regenerator manifold. Thefoam gasket 355 is placed inside theexterior cover 136. When theexterior cover 136, theupper casing 130 and thelower casing 132 are fastened together, thefoam gasket 355 is compressed, thereby sealing air flow around eachfilter 102″A-102″D. Thegasket 355 is preferably made of commercially available {fraction (3/16)} inch thick polyvinyl (PVC) foam sheeting. - Alternatively, as best shown in FIG. 14,
HRV 100″ may be constructed without the filter stops 317 and without thefoam gasket 355. In this aspect ofHRV 100″, thestationary seal 354 includes a plurality ofcompressible seals 354′, preferably woolen felt pads, placed in theregenerator manifolds 182A-182D next to theregenerative heat exchangers 102″A-102″ in the manner disclosed in U.S. patent application Ser. No. 08/893,833, which disclosure, applicants hereby incorporate by reference. In this equivalent method of sealing,seals 354′ seal off air flow leaking around afilter 102″ when thefilter 102″ is placed in a regenerator manifold 182″. All other aspects of this aspect of the present invention are as described herein throughout. - In either way of using stationary seal(s)354, the
regenerative heat exchanger 102″ has theheat exchanger depth 357 which is sufficiently less than thedepth 316 of the rectangular manifold 182. This difference in depth dimensions provides that a sufficientair distribution plenum 360 is formed between theinside climate side 108″ of theregenerative heat exchanger 102″ and theregenerator bulkhead 178. The volume of theplenum 360 is significantly less than a volume of air contained in theregenerative heat exchanger 102″. Preferably, the volume ofplenum 360 is 10% to 20% of the volume of the air contained in the preferredregenerative heat exchanger 102″. - The volume of air contained in the
regenerative heat exchanger 102″ of the most preferred embodiment of pleated HEPA filter material is easily calculated. The air volume betweenadjacent pleats 105 is a solid triangular shaped volume approximated by a triangular crosssectional area 450 between a pair ofadjacent pleats 105, and then multiplied by aheight 452 of thepleat 105. All the air volumes are summed to approximate the volume of air in theregenerative heat exchanger 102″. Where the glue bead 111 is present, the volume taken by the bead is approximated and subtracted from the aforementioned sum of all the air volumes. If theair plenum volume 360 is too large, then there is a dead volume generated, reducing the flow through theregenerative heat exchangers 102″A-102″D. - To continue explaining the workings of the
HRV 100″, thefresh air blower 114 draws air from aplenum 366 formed by thesecond compartment 232 and themotor side plate 260 of therotating air switch 116. Thisplenum 366 has a volume approximately corresponding to the volume of the second compartment minus the volumes of theblower 114 andmotor 120. The only opening is theopening 270 in themotor side plate 260. Hence, fresh air is drawn throughopening 270. This opening is connected to theopening 272 of the regenerator side plate 262-by themanifold 276 of therotating air switch 116. Thus, simultaneously a fresh airstream is drawn (forced) in throughopening 272 of theregenerator side plate 262 while the stale airstream is blown out throughopening 274. - As best shown in FIG. 8, the
horizontal regenerator bulkhead 302 and the centervertical bulkhead 304 divide thecircular opening 188 in theregenerator bulkhead 178 into four 90° quadrants (368, 370, 372, 374). Each quadrant is an opening into one of the fourregenerator manifolds 182A-182D. Thusquadrant 368 opens intoregenerator manifold 182A.Quadrant 370 opens intoregenerator manifold 182B.Quadrant 372 opens intoregenerator manifold 182D.Quadrant 374 opens intoregenerator manifold 182C. As therotating air switch 116 turns, each quadrant is exposed to thefresh air opening 272 of theregenerator side plate 262, then to thestale air opening 274, then to thefresh air opening 272, and so on. - The flow of the stale air out of the
regenerative heat exchangers 102″A-102″D and the flow of the fresh air into theregenerative heat exchangers 102″A-102″D is illustrated schematically in FIGS. 13A-13D. Theregenerative heat exchangers 102″A-102″D,stationary seals 354 andexterior cover 136 have been removed to best illustrate the travel of therotating air switch 116 with respect to the regenerator manifolds 182A182D. The arrows illustrate the air flow as will be discussed subsequently. FIG. 13A shows the rotating air switch in the position shown in FIG. 8. In actual operation, theregenerative heat exchangers 102″A-102″D, and the filter stops 317 (if used) are in place in theregenerator manifolds 182A-182D; the stationary seal(s) 354 is/are in place and theexterior cover 136 is attached as is shown in FIG. 1. - As best shown in FIG. 13A, for the
rotating air switch 116 in the position shown with thebulkhead 304 bisecting theopening 274 and also bisecting theopening 272, (e.g., the position shown in FIG. 8) fresh air is drawn in through the lower tworegenerator manifolds 182C-182D while stale air is blown out through the upper tworegenerator manifolds - Referring now to FIG. 13B, assuming a clockwise rotation, a quarter turn (i.e., 90°) of the
rotating air switch 116 from the one shown in FIG. 13A, the right two regenerator manifolds (182B, 182D) receive an outward flow of stale air while the two leftmost regenerator manifolds (182A, 182C) receive an inward flow of fresh air. - Referring now to FIG. 13C, a half turn (i.e., 180°) of the
rotating air switch 116 position as from the one shown in FIG. 13A, the lower two regenerator manifolds (182C, 182D) receive an outward flow of stale air while the upper two regenerator manifolds (182A, 182B) receive an inward flow of fresh air. Thus in a 180 degree turn there is a reciprocating air flow in a regenerator bed. - Referring now to FIG. 13D, for a three quarters (i.e., 270°) of a turn of the rotating air switch position from the one shown in FIG. 13A, the left two regenerator manifolds (182A, 182C) receive an outward flow of stale air while the right two regenerator manifolds (182B, 182D) receive an inward flow of fresh air.
- In this way, each
regenerator manifold 182A-182D, and eachregenerative heat exchanger 102″A-102″D, respectively, contained therein, receives a reciprocating flow of stale air flowing outward to the outside climate, followed by fresh air flowing inward to the inside climate. Heat and moisture (if any) are thus transferred from the outwardly flowing stale air to the inwardly flowing fresh air by theregenerator matrix 104″. Since theregenerative heat exchangers 102″A-102″D are made of a pleated HEPA filter material, the inward flow of fresh air passing through the regenerative heat exchangers is not only provided with heat and moisture, but is also filtered. Likewise the outwardly flowing stale air, in addition to releasing heat and moisture on theheat exchange matrix 104″A-104″D, is also filtered as it passes through theregenerative heat exchangers 102″A102″D. - The
HRV 100″ uses a number of clearance seals which are noncontacting, e.g., they are air gaps. As previously described, there is aclearance seal 118 between themotor side plate 260 of therotating air switch 116 and themotor bulkhead 176. There is aclearance seal 119 between theregenerator side plate 262 of the rotating air switch and theregenerator bulkhead 178. - Furthermore, there are two face clearance seals between the
horizontal regenerator bulkhead 302, and theregenerator side plate 262 and also two face clearance seals between the centervertical regenerator bulkhead 304 and theregenerator side plate 262. These four noncontacting clearance seals 380, 382, 384 and 386 are best shown on FIG. 8 and are preferably air gaps of approximately 0.015 inches, but may suitably range from 0.005 inches to 0.035 inches.Clearance seal 380 is between the top portion ofvertical bulkhead 304 andside plate 262 forming an air leakage path betweenregenerator manifold Clearance seal 384 is between the bottom portion ofvertical bulkhead 304 andside plate 262 forming an air leakage path between regenerator manifold 182C and 182D.Clearance seal 382 is between the right portion ofhorizontal bulkhead 302 andside plate 262 forming an air leakage path between regenerator manifold 182B and 182D.Clearance seal 386 is between the left portion ofhorizontal bulkhead 302 andside plate 262 forming an air leakage path betweenregenerator manifold stale air blower 112 and negatively pressurized air entering thefresh air blower 114. Hence, all clearance seal leakage causes stale air to enter the fresh airstream entering thefresh air blower 114 without entering theregenerative heat exchangers 102″A-102″D. This has the effect of reducing the ventilation rate, however there is no effect on the level of filtration. Advantageously, the clearance seal leakage of clearance seals 118, 119, 380, 382, 384, and 386 does not reduce heat recovery, nor filtration efficiency. In contrast, much of the seal leakage in the prior art rotating wheel regenerator has the effect of reducing heat recovery. Indeed, if a rotating regenerator wheel were made of HEPA filter material, the seal leakage would cause ventillation air to bypass the HEPA filter, thereby defeating the HEPA filtration. - As best shown in FIGS.1-16D, for the
HRV 100″, the fresh filtered airstream is driven by thefresh air blower 114 out throughopenings 175 and enters the room directly. The filtered stale air stream exits throughopenings 208 in theexterior cover 136. - The invention may be modified. Although the present invention preferably utilizes four
regenerator manifolds 182A-182D and four stationaryregenerative heat exchangers 102″A-102″D, the number of regenerator manifolds and regenerative heat exchangers can be different than four. Two can be used, for example, by simply removing the centervertical bulkhead 304. In this case, there will be part of the time when stale airstream flows directly to thefresh air blower 114. This is known in the art as flow “short-circuiting”. The amount of time that this occurs can be reduced by reducing the angle of the preferred pie shapedopenings openings rotating air switch 116 having approximately 90° angled pie shapedopenings openings regenerative heat exchangers 102″A-102″D and is most desirable because it provides minimal air pressure drop. - Instead of a
separate gear motor 117 to operate therotating air switch 116, power can be taken from theelectric blower motor 120. This reduces cost of constructing theHRV 100″ and operating theHRV 100″ but, makes it more difficult to stop the rotation of therotating switch 116 while theblowers - The clearance seals118, 119 around the rotating
air switch 116 may be replaced by tighter contact seals, as is known in the art, since flow through the clearance seals causes some stale air to return to the fresh airstream. - The
housing 122,bulkheads air switch 116 of theHRV 100″ of the present invention can be fabricated of sheet metal, using conventional metal fabricating techniques. Alternatively they made be made of plastics, such as, but not limited to PVC, using suitable plastic molding techniques. Commercially available components are used for the blowers, blower motor, switches, gear motor, pulleys, timing belt, electrical wire and electrical outlet materials used in the construction of theHRV 100″. - Also, providing the device of the present invention with the additional optional gear motor switch244 (which is used to just turn off and on the gear motor) and its associated wiring makes the device of the present invention a convertible device, e.g., convertible between operating as a heat recovery ventilator (which provides air filtration, as well as, heat and moisture exchange) and operating as only a console air cleaning/filtration device. Thus the convertible device eliminates the need for two separate devices. The operation of
HRV 100″ has been explained in detail above as to how both filtration and heat and moisture exchange of the air occurs when therotating air switch 116 is operating, e.g, turning. TheHRV 100″ can be operated as a console HEPA air cleaning device by not operating therotating air switch 116, e.g. turning offgear motor 117 usingswitch 244, but, leaving the blowers operating. This may be done in two ways. If the device is left in thewindow frame 124 at this time, it acts as a source control filtering incoming fresh air and filtering outgoing stale air. Here therotating air switch 116 will no longer rotate but instead will be in a stationary or fixed position relative to any of theregenerative heat exchangers 102″A-102″D. A fresh air stream will flow into theHRV 100″ through theopenings 208 in theexterior cover 136, pass through one or more of the pleated HEPA filter materialregenerative heat exchangers 102″A-102″D and be filtered from outdoor particulates, allergens and/or pollutants. At this point source control of pollutant, allergens and particles from the outside fresh air occurs The filtered fresh air then enters into theopening 272 in theair switch 116. The filtered fresh air is then transported to thesecond compartment 232 where the fresh filtered air is forced out of thehousing 122 throughopenings 175 as previously described. Meanwhile, at the same time stale air entersopenings housing 122, and is moved through theblower 112 in thefirst compartment 230 into thethird compartment 234 and into theair switch 116. It is transported from theair switch 116 into thefourth compartment 236 where it passes through one or more of the pleated HEPA filter materialregenerative heat exchangers 102″A-102″D where the stale indoor air is filtered. The filtered stale air then flows out of theopenings 208 in theexterior cover 136 of thehousing 122. Since theopenings air switch 116 are approximately 90° apart, differentregenerative heat exchangers 102″A-102″D are used for the fresh air stream and for the stale air stream. - There is a second way the present invention can be used as an air cleaning device, when the rotating air switch is not operating, and
additional switch 244 and its associated wiring is present on the device. Here thedevice HRV 100″ is removed from thewindow frame 124 and placed within the room of the structure and operated as a stand alone console HEPA air cleaning device. It operates as just previously described but instead of a fresh air stream entering the device throughopenings 208 inexterior cover 136, it is stale room air that enters the device. The stale room air also entersopenings air switch 116 is turned off (e.g., not rotating), the heat and moisture is not exchanged between the respective airstreams, but the air is filtered, as it passes through the HEPA filter material. - The present invention is further explained by the following examples which should not be construed by way of limiting the scope of the present invention.
- An HRV was constructed according to the disclosure above using sheet metal for the housing, all bulkheads, baffle and rotating air switch, using commercially available components for the blowers, blower motor, switches, electrical cord, plug, wiring, gear motor, pulleys and timing belt, and using a plurality of
compressible seals 354′ which were felt wool pads, placed around each rectangular heat exchanger, as shown in FIG. 14. The blower used was a DAYTON™ low profile blower, stock number 4C826 commercially available in the GRAINGER 1997 CATALOG(NO.388), of W.W.Grainger, Inc., Palatine Ill. The gear motor used was a HURST™ instrument motors unit, commercially available from the aforementioned GRAINGER 1997 CATALOG, stock number 6Z540. The HRV had a continuously variable blower switch which also served as the on-off switch for both the blower and the gear motor which drove the rotating air switch. There was an additional on-off switch for the gear motor which allowed the gear motor to be turned off while the blower remained on. - The rectangular regenerative heat exchanger HEPA filter beds were purchased from Columbus Industries, Inc. of Ashville, Ohio. This pleated HEPA filter material was listed as “3282 media at 6 pleats per inch with a 1 inch glue spacing”. The HEPA filter material was about 0.015±0.001 inches thick.
- The rectangular regenerative heat exchangers HEPA filters/regenerator beds made by Columbus Industries, Inc. were made by transversely accordian pleating a strip of HEPA filter material having 1″ inch glue bead spacings on the strip to form a HEPA filter unit having V-shaped pleats. The HEPA filter unit was glued along the four sides of the periphery of the HEPA filter unit into a chipboard frame. The dimensions of the assembled regenerative heat exchanger was about 2.81 inches high (pleat height) by about 6.4 inches wide by about 2.9 inches deep (pleat depth) with a frequency of 6 pleats per inch. Thus there were about 38 pleat edges across the 6.4 inch width. The frame opening was about 5⅝ inches by about 2.5 inches. The thickness of the chipboard used in the chipboard frame was about 0.020 inches. Each glue bead was about {fraction (1/16)} inch high by about {fraction (1/16)} inch thick. The glue beads contacted each other except for about 0.2 inches from the pleat folds. The pleats were approximately parallel for much of the pleat depth. (The pleat depth of the regenerative heat exchanger is the depth in the air flow direction.) Thus the spacing from adjacent pleat edge to adjacent pleat edge was about 0.050 inches. The period of time of rotation of the rotating air switch was 6 seconds for a 360° turn. The HRV was placed in a window opening.
- The HRV had the following measured performance characteristics with the blower on “high”:
- Maximum power requirement: 85 W
- Maximum ventilation rate: 40 CFM
- Effectiveness (sensible): 75%
- The housing dimensions of the HRV were (depth×width×height): 13″×16″×7½″
- The ventilation rate of 40 CFM was sufficient to provide 0.2 of an air change per hour for a 1500 square-foot residence. When the device was run with the HEPA filter regenerative filter heat exchanger material, it provided over 2.5 filtered air changes per hour for a 10-foot-by-12-foot bedroom with an 8 foot ceiling. This provided excellent air quality for an allergy or asthma sufferer for healthy sleeping.
- The sensible heat recovery effectiveness of 75% was excellent. When the outside temperature was 40° F. less that the inside temperature, the heat loss was only about 126 W. The blower motor in the second compartment was placed so that its heat returned to the structure. This positive heat is not counted in the loss of 126 W.
- The HRV made according to Example 1 was operated as a standard console HEPA filter air filtration device to filter indoor room air. The HRV was left in the window, but the gear motor was turned off, while the blowers remained on. Thus the air switch, no longer rotated, but remained in a stationary position. When this occurred, there was balanced flow filtered ventillation without heat recovery. The balanced air flow rate was about 40 CFM. There are times when this is desirable, for example, on a cool summer night with a hot building. In this mode of operation the HRV also performed the function of source control, filtering outdoor air of pollutants, particulates, and/or allergens.
- The HRV made according to Example 1 was operated as a standard console HEPA air filtration device to filter indoor room air. The HRV was removed from the window and placed within a room of a structure. The gear motor was turned off while the blowers were turned onto high. When this occurred, there was balanced flow filtered air flow without heat recovery. The flow rate when using the HRV as a console HEPA filter air filtration device was about 80 CFM. This air flow is about twice as great as in Example 1.
- While the present invention has now been described and exemplified with some specificity, those skilled in the at will appreciate the various modifications, including variations, additions, and omissions, that may be made in what has been described. Accordingly, it is intended that these modifications also be encompassed by the present invention and that the scope of the present invention be limited solely by the broadest interpretation that lawfully can be accorded the appended claims.
Claims (24)
1. A heat recovery ventilator for use in ventilating a room, or the like, comprising:
means for venting a stale airstream of an indoor climate to the outside air;
means for supplying a fresh airstream from the outside air of an outside climate;
at least two stationary regenerative heat exchangers made of a pleated HEPA filter material; and
a rotating air switch for transferring the stale airstream to the regenerative heat exchangers from the means for venting the stale airstream of the indoor climate and for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate, said rotating air switch being rotatably mounted and including:
(a) a first circular side plate having an air flow opening therein,
(b) a second circular side plate having a pair of air flow openings, said second plate spaced apart and disposed opposed and parallel to said first plate, and
(c) a single manifold extending from said air flow opening in said first side plate to one of said pair of said air flow openings in said second side plate, said manifold enclosing said air flow opening in said first side plate and said one of said air flow openings in said second side plate and forming a fresh air passage way for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate, said other opening in said second side plate forming a stale air passageway for transferring the stale airstream from the means for venting the stale airstream of the indoor climate to the regenerative heat exchangers; and wherein air flows in opposite directions through the same regenerative heat exchanger.
2. The heat recovery ventilator of , wherein said air switch is isolated from the outside climate by said regenerative heat exchangers.
claim 1
3. The heat recovery ventilator of , further comprising a plurality of noncontacting clearance seals, one said noncontacting clearance seal disposed between said first circular plate of said rotating air switch and both the means for venting the stale airstream of the indoor climate and the means for transferring the fresh airstream from the outside air of the outside climate, and said remaining noncontacting clearance seals disposed between said second circular plate and said stationary regenerative heat exchangers.
claim 1
4. The heat recovery ventilator of , further comprising four regenerative heat exchangers.
claim 1
5. The heat recovery ventilator of , wherein said pleated HEPA filter material has a pleat density of 6 pleats per inch.
claim 1
6. The heat recovery ventilator of , wherein said HEPA filter material captures at least 99.97% of particles having a diameter greater than 0.3 microns.
claim 1
7. The heat recovery ventilator of , wherein said HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
claim 1
8. A heat recovery ventilator for use in a room or the like, comprising a housing, two blowers, at least two stationary regenerative heat exchangers made of a pleated HEPA filter material, a shaft, a single rotating air switch mounted on said shaft, a motor for driving said blowers and said shaft, one of said blowers for forcing a stale airstream out of the room; the other of said blowers for forcing a fresh airstream into the room, said air switch, in use, alternately imparting the stale airstream from one said blower to a regenerative heat exchanger, then imparting the fresh airstream to that same heat exchanger and through said other blower, when said air switch rotates in a 180° turn.
9. The heat recovery ventilator of , wherein said rotating air switch has:
claim 8
(a) a first side plate having an opening and having a center shaft aperture,
(b) a second side plate having two openings spaced from each other, and a center shaft aperture,
(c) a single manifold extending from said first side plate to said second side plate, wherein said manifold connects said opening of said first side plate with one of said openings in said second side plate forming a fresh air passageway, and
(d) a shaft receiving portion extending from said first side plate to said second side plate;
wherein said rotating switch is disposed upon said shaft, said shaft disposed in said shaft receiving portion, and wherein, in use, the fresh airstream flows from said regenerative heat exchangers through said fresh air passageway and is forced out by said other blower, and wherein said other opening of said second side plate along with a portion of the manifold and a portion of the shaft receiving portion form a stale air passageway from said one blower to said regenerative heat exchangers, for transferring the stale airstream to said regenerative heat exchangers.
10. The heat recovery ventilator of , wherein said housing has:
claim 8
(a) first compartment containing said one blower, said first compartment having a plurality of openings therein for forcing the stale airstream to flow into said housing and through said one blower,
(b) a second compartment containing said other blower and said motor, said second compartment having a plurality of openings therein for permitting the fresh airstream to exit the housing and to enter the room,
(c) a third compartment containing said rotating air switch, and
(d) a fourth compartment containing said regenerative heat exchangers, said fourth compartment having a plurality of openings therein for forcing the stale airstream out of said fourth compartment and for allowing the fresh airstream to be drawn into said fourth compartment.
11. The heat recovery ventilator of , wherein
claim 10
(a) said first compartment is next to said second compartment and shares a common blower bulkhead,
(b) said third compartment is adjacent to both said first compartment and said second compartment and shares a common motor bulkhead with said first compartment and said second compartment, said motor bulkhead having a first opening into said first compartment and a second opening into said second compartment, and
(c) said fourth compartment is spaced from said first and second compartments and is adjacent to said third compartment, said fourth compartment sharing a common regenerator bulkhead with said third compartment, said regenerator bulkhead having an opening therein, said rotating air switch disposed in said third compartment with one end of said rotating air switch adjacent the opening in the regenerator bulkhead and the other end of said rotating air switch adjacent to the opening in the motor bulkhead between the second and third compartments.
12. The heat recovery ventilator of , wherein said HEPA filter material captures at least 99.97% of particles having a diameter greater than 0.3 microns.
claim 6
13. The heat recovery ventilator of , wherein said HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
claim 6
14. A method of providing indoor ventilation, air filtration and source control using a heat recovery ventilator having stationary rectangular regenerative heat exchangers, a manifold for accepting the stationary rectangular regenerative heat exchangers, two blowers, one rotating air switch, a motor for driving the blower and air switch, all disposed in a housing, the housing having stale air openings for allowing a stale airstream to enter the housing and fresh air openings for allowing filtered fresh air to exit from said housing; the method comprising the steps of:
(a) selecting the rectangular regenerative heat exchangers made of a pleated HEPA filter material;
(b) disposing said stationary rectangular regenerative heat exchangers in the manifold;
(c) forcing a stale airstream from an indoor climate into the housing,
(d) blowing the stale airstream into the rotating air switch,
(e) transporting the stale airstream from the rotating air switch into the stationary rectangular regenerative heat exchangers,
(f) simultaneously exchanging heat and moisture from the stale airstream onto the regenerative heat exchangers, filtering the stale air stream, and forcing the filtered stale airstream to flow out of the housing,
(g) forcing a fresh air stream into the housing and through the same regenerative heat exchangers,
(h) exchanging heat and moisture on the regenerative heat exchangers into the fresh airstream and simultaneously filtering the fresh airstream,
(i) forcing the filtered fresh airstream, which is heated and moisturized, into the rotating air switch and through the fresh air blower, and
(j) forcing the filtered fresh airstream, which is heated and moisturized, out of the housing and into the indoor climate.
15. The method of , wherein the rotating air switch includes:
claim 14
(a) a first side plate having an opening and having a center shaft aperture,
(b) a second side plate having two openings spaced from each other, and a center shaft aperture,
(c) a shaft receiving portion extending from said first side plate to said second side plate and connecting said center shaft apertures,
(d) a single manifold extending from said first side plate to said second side plate, said manifold connecting said opening of said first side plate with one of said openings in said second side plate and forming a fresh air passageway there between, said other of said openings of said second side plate along with a portion of said manifold and a portion of said shaft receiving portion forming a stale air passageway from said first blower to said regenerative heat exchanger,
and wherein the method further comprises in step (d) blowing the stale airstream into the stale air passageway, in step (e) transporting the stale airstream from the stale air passageway in the rotating air switch into the stationary regenerative heat exchangers, and in step (i) forcing the filtered fresh airstream into the fresh air passageway in the rotating air switch and through the fresh air blower.
16. The method of , wherein said step of selecting said regenerative heat exchangers made of said HEPA filter material includes selecting said HEPA filter material which captures at least 99.97% of particles having a diameter greater than 0.3 microns.
claim 14
17. The method of , wherein said step of selecting said regenerative heat exchangers made of said HEPA filter material includes selecting HEPA filter material rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
claim 14
18. A method of providing indoor ventillation, air filtration and air pollution source control using a heat recovery ventilator having means for venting a stale airstream of an indoor climate to the outside air, means for supplying a fresh airstream from the outside air of an outside climate, and a regenerative heat exchanger, the method comprising the steps of:
(a) selecting a regenerative heat exchanger of a pleated HEPA filter material;
(b) positioning said regenerative heat exchanger in a stationary position to intercept a fresh air stream and to intercept a stale air stream;
(c) venting the stale airstream from an indoor climate into the ventilator and into said regenerative heat exchanger with the means for venting the stale airstream of an indoor climate to the outside air;
(d) simultaneously exchanging heat and moisture from the stale airstream onto said regenerative heat exchanger, filtering the stale air stream, and forcing the filtered stale airstream to flow out of the ventilator,
(e) supplying fresh air into the ventilator and through the same regenerative heat exchanger with the means for supplying the fresh air stream from the outside air of an outside climate,
(f) exchanging heat and moisture on the regenerative heat exchanger into the fresh airstream and simultaneously filtering the fresh airstream, and
(g) forcing the fresh filtered airstream, which is heated and moisturized, out of the ventilator and into the indoor climate.
19. The method of , wherein said selecting step includes selecting said regenerative heat exchanger of said pleated HEPA filter material wherein said HEPA filter material captures at least 99.97% of particles having a diameter greater than 0.3 microns.
claim 18
20. The method of , wherein said selecting step includes selecting said regenerative heat exchanger of said pleated HEPA filter material wherein said HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
claim 18
21. A convertible device which converts between a heat recovery ventilator providing filtered, heat and moisture conditioned air and an air filtration device providing filtered air alone, said convertible device comprising:
means for venting a stale airstream of an indoor climate to the outside air;
means for supplying a fresh airstream from the outside air of an outside climate;
at least two stationary regenerative heat exchangers made of a pleated HEPA filter material;
an air switch for transferring the stale airstream to the regenerative heat exchangers from the means for venting the stale airstream of the indoor climate and for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate, said air switch being rotatably mounted; and
means for controlling rotation of the air switch between a stationary and a rotating configuration;
wherein, said air switch is rotated when said convertible device is operated as a heat recovery ventilator providing filtered, heat and moisture conditioned air and wherein said air switch remains stationary when said convertible device is operated as an air filtration device providing filtered air alone.
22. The heat convertible device of , wherein said HEPA filter material captures at least 99.97% of particles having a diameter greater than 0.3 microns.
claim 21
23. The heat convertible device of , wherein said HEPA filter material is rated at least 85% Dust-Spot Efficiency percentage as measured by ASHRAE Standard 52.1-1992, Dust-Spot Procedure.
claim 21
24. A heat recovery ventilator for use in ventilating a room, or the like, comprising means for venting a stale airstream of an indoor climate to the outside air, means for supplying a fresh airstream from the outside air of an outside climate, at least two stationary regenerative heat exchangers and a rotating air switch for transferring the stale airstream to the regenerative heat exchangers from the means for venting the stale airstream of the indoor climate and for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate, said rotating air switch being rotatably mounted and including:
(a) a first circular side plate having an air flow opening therein,
(b) a second circular side plate having a pair of air flow openings, said second plate spaced apart and disposed opposed and parallel to said first plate, and
(c) a single manifold extending from said air flow opening in said first side plate to one of said pair of said air flow openings in said second side plate, said manifold enclosing said air flow opening in said first side plate and said one of said air flow openings in said second side plate and forming a fresh air passage way for transferring the fresh airstream from the regenerative heat exchangers to the means for supplying the fresh airstream from the outside air of the outside climate, said other opening in said second side plate forming a stale air passageway for transferring the stale airstream from the means for venting the stale airstream of the indoor climate to the regenerative heat exchangers; and wherein air flows in opposite directions through the same regenerative heat exchanger.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US09/812,972 US20010018964A1 (en) | 1997-07-11 | 2001-03-19 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/893,833 US6257317B1 (en) | 1997-07-11 | 1997-07-11 | Integrated heat recovery ventilator-hepa filter |
US09/082,171 US6289974B1 (en) | 1997-07-11 | 1998-05-20 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
US09/812,972 US20010018964A1 (en) | 1997-07-11 | 2001-03-19 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
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US09/082,171 Continuation US6289974B1 (en) | 1997-07-11 | 1998-05-20 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
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US20010018964A1 true US20010018964A1 (en) | 2001-09-06 |
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US09/812,972 Abandoned US20010018964A1 (en) | 1997-07-11 | 2001-03-19 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
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US09/082,171 Expired - Fee Related US6289974B1 (en) | 1997-07-11 | 1998-05-20 | Integrated heat recovery ventilator HEPA filter using a HEPA filter material regenerative heat exchanger |
Country Status (3)
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US (2) | US6289974B1 (en) |
CA (1) | CA2294335A1 (en) |
WO (1) | WO1999060307A1 (en) |
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- 1999-05-19 CA CA002294335A patent/CA2294335A1/en not_active Abandoned
-
2001
- 2001-03-19 US US09/812,972 patent/US20010018964A1/en not_active Abandoned
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US3047272A (en) * | 1958-02-21 | 1962-07-31 | Combustion Eng | Heat exchanger |
US4685944A (en) * | 1982-06-09 | 1987-08-11 | Flanders Filters, Inc. | High efficiency particulate air filter |
US4688626A (en) * | 1984-06-28 | 1987-08-25 | Paul Tengesdal | Ventilator unit |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
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EP1548374A1 (en) * | 2002-08-05 | 2005-06-29 | Daikin Industries, Ltd. | Air conditioner |
EP1548374A4 (en) * | 2002-08-05 | 2008-02-13 | Daikin Ind Ltd | Air conditioner |
US20070091571A1 (en) * | 2005-10-25 | 2007-04-26 | Malone Christopher G | Heat exchanger with fins configured to retain a fan |
EP1987295A2 (en) * | 2006-02-20 | 2008-11-05 | LG Electronics Inc. | Air conditioning system and control method thereof |
EP1987295A4 (en) * | 2006-02-20 | 2012-03-14 | Lg Electronics Inc | Air conditioning system and control method thereof |
US9073061B2 (en) * | 2011-12-02 | 2015-07-07 | W. L. Gore & Associates, Inc. | Heat stabilized composite filter media and method of making the filter media |
US20140190656A1 (en) * | 2013-01-07 | 2014-07-10 | Carrier Corporation | Energy recovery ventilator |
US10041743B2 (en) * | 2013-01-07 | 2018-08-07 | Carrier Corporation | Energy recovery ventilator |
US10852071B2 (en) | 2013-01-07 | 2020-12-01 | Carrier Corporation | Method of operating an energy recovery system |
US20160041138A1 (en) * | 2014-08-11 | 2016-02-11 | Arizona Board Of Regents On Behalf Of Arizona State University | Methods for Monitoring Airborne Contaminants and Agents using Atmospheric Condensate |
US20170350607A1 (en) * | 2016-06-06 | 2017-12-07 | Delta Electronics, Inc. | Hybrid air conditioning apparatus |
CN108105978A (en) * | 2017-12-08 | 2018-06-01 | 珠海格力电器股份有限公司 | Wind deflector fixing structure and with its air conditioner |
EP4008977A1 (en) * | 2020-12-03 | 2022-06-08 | Wilms NV | Ventilation unit with casing |
BE1028853B1 (en) * | 2020-12-03 | 2022-07-05 | Wilms Nv | Ventilation unit with casing |
CN116518474A (en) * | 2023-05-26 | 2023-08-01 | 杭州捷瑞空气处理设备有限公司 | Energy-saving variable dehumidification capacity heat pump type runner dehumidification unit |
Also Published As
Publication number | Publication date |
---|---|
US6289974B1 (en) | 2001-09-18 |
CA2294335A1 (en) | 1999-11-25 |
WO1999060307A1 (en) | 1999-11-25 |
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Legal Events
Date | Code | Title | Description |
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STCB | Information on status: application discontinuation |
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