Electromagnetic energy heating system

A heating system for hot water and conditioned air uses electromagnetic energy created by one or more magnetrons operated by high voltage transformers. The heating system includes oil cooled transformers and magnetrons. Using radiators in the form of heat exchangers, heat recovered from the transformers and magnetrons is dissipated directly into the path of the return air and the air handler blower. The magnetron heating system includes a coiled conduit sized to allow complete heating of the fluid flowing therethrough. The conduit has a conical shape to allow upper magnetrons to heat the outside of the conduit and lower magnetrons to heat the inside of the conduit.

BACKGROUND OF THE INVENTION

The present invention relates in general to an electromagnetic energy heating system adapted for residential, commercial, and industrial applications. More particular, by way of example, the present invention relates to the use of microwave energy created by one or more magnetrons as a heat source for heating fluids to an elevated temperature for heat exchange applications.

Electromagnetic energy such as in the form of microwaves generated by a magnetron have been known for use in heating systems having various designs. By way of example, United States Pub. No. 2005/0139594 discloses the application of a magnetron in a water heater or boiler. U.S. Pat. No. 4,956,534 discloses the application of a magnetron in a heat exchanger having a frustoconical shape. See also U.S. Pat. No. 6,858,824 which discloses a microwave domestic hot water and radiant heating system.

The present invention provides a heating system using electromagnetic energy generated from one or more magnetrons in a manner heretofor unknown, which is described in the following detailed description.

BRIEF SUMMARY OF THE INVENTION

The present invention is generally directed to an electromagnetic energy heating system using one or more transformer operated magnetrons for generating microwave energy to produce economical and energy saving heat. For example, the system can be figured to use microwave energy to provide domestic hot water, as well as to heat a building, structure or other space to be conditioned in residential, commercial, and industrial applications.

In accordance with one embodiment of the present invention, there is disclosed an electromagnetic energy heating system, comprising: a housing forming an internal chamber in communication with an inlet and an outlet; a fluid heating unit within the chamber for heating a fluid therein; a magnetron for creating electromagnetic energy in communication with the heat exchange for heating the fluid therein; a transformer operably connected to the magnetron for the operation thereof; and a cooling system comprising a first circulation system for circulating cooling fluid between the magnetron and a magnetron heat exchanger, and a second circulating system for circulating cooling fluid between the transformer and a transformer heat exchanger.

In accordance with a further embodiment of the present invention there is disclosed an electromagnetic energy heating system comprising; a housing forming an internal chamber; a heating unit having a fluid therein formed from a coiled conduit having a conical shape within the chamber, the coiled conduit having an exterior surface area and an interior surface area, the coiled conduit including an upper end having a diameter smaller than a diameter of a lower end of the coiled conduit, the lower end having an opening in communication with the interior surface area of the coiled conduit; a first magnetron for creating electromagnetic energy directed toward the exterior surface area of the coiled conduit for heating the fluid therein; and a second magnetron for creating electromagnetic energy directed toward the interior surface area of the coiled conduit for heating the fluid therein.

In accordance with still another embodiment of the present invention there is disclosed an electromagnetic energy heating system, comprising: a housing forming an internal chamber in communication with an air inlet and an air outlet; a fluid heating unit within the chamber for heating a fluid therein; a system within the chamber operable for generating electromagnetic energy for heating fluid within the heating unit, the system creating heat within the chamber while generating electromagnetic energy; and an air passageway defined within the chamber between the air inlet and the air outlet in communication with the system; wherein air received through the air inlet and discharged through the air outlet is conditioned within the chamber by the heat created by the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In describing the preferred embodiments of the invention illustrated in the drawings, specific terminology will be used for the sake of clarity. However, the invention is not intended to be limited to the specific terms so used, and it is to be understood that each specific term includes all equivalence that operate in a similar manner to accomplish a similar purpose.

Referring now toFIG. 1, wherein like reference numerals represent like elements, there is shown an electromagnetic energy heating system in accordance with one embodiment of the present invention generally designated by the reference numeral100. The heating system100includes a housing102or cabinet constructed to contain the operative components, assemblies, sub-assemblies, systems, and subsystems as to be described hereinafter. The housing is constructed to include a discharge air outlet104and a return air inlet106as shown inFIG. 9. Although the air outlet104is illustrated arranged at the top of the housing102, and the air inlet106is arranged on a side panel of the housing, other arrangements of the outlet and inlet are contemplated pursuant to the present invention.

In addition, the housing102may include a removable service panel108to provide access to the interior of the housing for servicing the components, assemblies, sub-assemblies, systems and sub-systems therein. The service panel108may be provided with a key lock to prevent access to the interior of the housing by unauthorized individuals. A control panel110having a microprocessor for the operation of the heating system100may be provided on one of the side panels of the housing102. The operation of the heating system100may be controlled manually or programed by the control panel110, or remotely through a wireless connection to the control panel such as the Internet or through another wired or nonwired network.

The housing102, in accordance with the preferred embodiment, is substantially sealed except for the air outlet104and air inlet106. That is, the heating system100communicates with the surrounding environment substantially through the air outlet104and air inlet106. In this regard, the housing106provides a substantially enclosed environment sealed from the surrounding environment where the heating system is placed.

As will be understood from a further description of the heating system100, the use of electromagnetic energy created by magnetrons does not produce any toxic exhaust or combustion flue gases that require venting to the atmosphere. Therefore, there are no combustion flue ducts as conventionally found in gas or oil burning systems. For this reason, the heating system100can be placed anywhere within any open or closed area to be occupied without concern of contamination of the breathable air. The absence of combustion flue ducts provides the heating system100with a degree of portability for use not only in permanent installations, but in temporary installations such as portable localized heating systems where temporary conditioned heated air is required, for example, at work sights and the like.

The heart of the heating system102is a magnetron heating system112as shown inFIG. 2in accordance with one embodiment of the present invention. The magnetron heating system112includes a housing114defining an internal chamber116as shown through a cut out portion of the housing for illustration purposes. The housing114may be cylindrical in shape formed from a double wall construction having an air gap therebetween. The air gap provides radio frequency shielding from the electromagnetic energy created by the magnetrons, as well as thermal insulation. In the preferred embodiment, the housing114is constructed from stainless steel or other suitable materials.

A microwave transparent heating unit118is arranged within the internal chamber116of the housing114. The heating unit118in the preferred embodiment is constructed from an elongated conduit such as tubing120formed into a conical shape by coiling having a smaller diameter at its upper end and a larger diameter at its lower end or vise versa. The coiled tubing120provides an exposed exterior surface area as shown inFIG. 2, and an exposed interior surface area within the internal space formed by the coiled tubing (not shown). The coiled tubing120provides a continuous fluid flow path from its lower end to its upper end extending along the length of the internal chamber116. A tubing support122may be provided coupled to the coiled tubing120to maintain the tubing in its coiled conical shape. Although the heating unit118has been described in accordance with the preferred embodiment as having a conical shape, it is to be understood that other shapes such as cylindrical, oval, polygonal, and the like can be adopted for use in the magnetron heating system112of the present invention.

In accordance with one embodiment, the tubing120may be constructed from Teflon having an inside diameter of about 0.375 inches, although larger and smaller inside diameters are contemplated depending upon the size of the magnetron heating system112and its intended application. The preferred diameter of the tubular120allows complete heating of the tubing by exposure of its exterior and anterior surface areas to the electromagnetic energy generated by the magnetrons. In addition to Teflon, the tubing120can be constructed of glass or other microwave transparent materials. The advantage of Teflon versus other material is that Teflon has a high dielectric strength which makes it invisible to microwaves. Other advantages are the relatively low absorption of water by Teflon, which maintains its dielectric strength all the time, as well as having a relatively low thermal conductivity. This allows the heat generated by the electromagnetic energy to remain in the fluid flowing through the heating unit118.

The heating unit118is in fluid communication with a liquid to air heat exchanger124by a fluid supply conduit126coupled to the upper end of the tubing120and a fluid return conduit128coupled to the lower end of the tubing. A circulatory pump130is provided within the return conduit128for circulating fluid between the microwave heating unit118and the liquid to air heat exchanger124. The liquid to air heat exchanger124is constructed from a housing132having a plurality of interdigitated fluid conduits134. One section of interdigitated conduits134is shown outside of the housing132for illustration purposes only. It is to be understood that the interdigitated conduits134are preferably contained within the housing132. The microwave heating unit118and the liquid to air heat exchange124, via the supply and return conduits126,128form a closed fluid loop for the fluid being heated within the internal chamber116as the fluid flows through the tubing120.

An expansion tank136is in fluid communication with the closed loop to accommodate expansion and contraction of fluid therein during the heating and cooling cycles of the magnetron heating system112. The fluid within the magnetron heating system112may be any number of fluids, preferably nontoxic, such as water and the like. In the preferred embodiment, glycol can be used as the heating medium. The expansion tank136is in fluid communication with the supply conduit126and a pressure relief cap138.

The fluid flowing through the tubing120within the internal chamber116is heated by a magnetron system generating electromagnetic energy in the form of microwaves. In the preferred embodiment, a pair of waveguides140,142are coupled to the upper end of the housing114and a pair of waveguides144,146are coupled to the lower end of the housing114. A magnetron148is received within a housing150coupled to the end of each of the waveguides140,142,144,146. The waveguides direct the electromagnetic energy in the form of microwaves from the magnetrons148to the internal chamber116within the housing114at either the upper end or the lower end thereof. More particularly, the upper magnetrons148direct microwave energy through the upper waveguides140,142to the external surface area of the heating unit118within the internal chamber116. On the other hand, the lower magnetrons148direct microwave energy through the lower waveguides144,146to the interior surface area of the heating unit118within the internal chamber116. By directing microwaves to both the exterior and interior surface areas of the coiled tubing120forming the heating unit118, heating of the fluid therein is more efficient by allowing absorption of electromagnetic energy over substantially the entire surface area of the tubing120.

The present invention, in the preferred embodiment, has been described as being provided with a pair of upper and lower magnetrons148. However, it is to be understood that the present invention may incorporate only a single upper magnetron148and a single lower magnetron for heating the fluid flowing through the tubing120. Further, it is also contemplated that only one magnetron148can be incorporated into the magnetron heating system112of the present invention, arranged either at the upper or lower end of the microwave heating unit118. Typical, magnetrons are available ranging from 600 watts to 3000 watts in capacity. The size and number of magnetrons will be determined by the size of the space to be heated using the heating system100when conditioning a volume of air in a room or the like. By way of example, it is contemplated that a 1500 to 2000 square foot facility will incorporate four magnetrons, each of 1000 watts, arranged as illustrated and described inFIG. 2. Likewise, the use of the heating system100for heating hot water will incorporate magnetrons of varied capacity and number depending upon the hot water demands of the application.

Each of the magnetrons148are electrically coupled to a transformer152such as shown inFIG. 6. Referring toFIG. 6, the transformers152are preferably submerged in a cooling fluid contained within a transformer cooling tank154having a fluid inlet156and a fluid outlet158. Each transformer152is electrically connected to a magnetron148via high voltage and line voltage terminals160. Each tank154is filled with a cooling fluid such as mineral oil and the like. In the preferred embodiment as thus far described, a pair of transformers152for the upper magnetrons148will be submerged in a mineral oil bath within a single tank154. Likewise, a pair of transformers152operably coupled to the lower magnetrons148will be submerged in a mineral oil bath within a single tank154. However, it is contemplated that each of the transformers152may be immersed in separate cooling fluid tanks, or more than two transformers may be provided within a single tank.

By way of one example, each transformer is a high voltage transformer, 240V/60 Hz class 220 transformer. In a preferred embodiment, each transformer includes a thermal cutout in thermal contact with the transformer windings. This provides a safety feature in case of an oil cooling failure. The windings are also made to a higher heat standard than normal microwave transformers. In use, the upper and lower magnetrons148are pulsed using a half-wave voltage doubler. The upper magnetrons148are fired by the first half-wave of the line voltage and the lower magnetrons are fired by the second half-wave. This fires the magnetrons alternatively as opposed to simultaneously.

Heat is generated within the housing102of the heating system100during operation of the magnetrons148and transformers152. For the efficient operation of the heating system100, it is preferred that the magnetrons148and transformers152be cooled, and that the heat be recovered for use in the heating system100. For this purpose, the heating system100includes a magnetron and transformer fluid cooling and heat recovery system162as shown inFIG. 3. The cooling and heat recovery system162can be broken down into a magnetron fluid cooling system164as shown inFIG. 4and a transformer fluid cooling system166as shown inFIG. 5.

Referring toFIGS. 3 and 4, the magnetron cooling system164includes a heat exchanger168, a circulation pump170, an optional expansion tank172and miscellaneous tubing174connecting the aforementioned components. The housings150for the upper magnetrons148are ganged together by tubing175. Likewise, the housings150for the lower magnetrons148are ganged together by tubing175. The pump170is operative for recirculating the cooling fluid such as mineral oil, glycol and the like contained within the housings150for the magnetrons148through the heat exchanger168. The expansion tank172is in fluid communication via tubing176to the tubing174adjacent the heat exchanger168. The magnetron cooling system164enables the recovery of heat generated by the magnetrons148via the heat exchanger168as to be described.

The transformer cooling system166includes the transformer tanks154, pump178, heat exchanger180, an expansion tank172and tubing182interconnecting the components in fluid communication with each other. Tubing184couples the cooling fluid within one of the transformer tanks154to the expansion tank172. The heat generated by the transformers152within the tanks154may be recovered by circulating the cooling fluid through the heat exchanger180as to be described. In the preferred embodiment, the transformers152are maintained at an operational temperature of about 210 degrees Fahrenheit by emersion within the cooling fluid within the tanks154. The magnetron heating system112and cooling and heating recovery system162is arranged within the housing102as shown inFIGS. 7 and 8.

Referring now toFIGS. 7 and 8, there will be described the assembly of the thus far described components within the housing102of the heating system100. The air inlet106may be provided with one or more controlled baffles186or dampers for regulating the volume of return air flow into the heating system100. A blower188has side air intakes190and an upwardly directed discharge opening192. The magnetron cooling heat exchanger168is positioned opposing the air inlet106for heat recovery of the heat generated by the magnetrons during operation of the magnetron heating system112. The transformer cooling heat exchanger180is arranged in the airflow path of the discharge opening192of the blower188for likewise heat recovery. The liquid to air heat exchange124is arranged underlying air outlet104. The magnetron heating system112and transformer tanks154are located generally within the interior of the housing102. As previously described, the housing102is preferably sealed but for the air outlet104and air inlet106.

Return air is pulled through the air inlet106by the blower188. The incoming air is circulated within the interior of the housing102picking up any internal heat from the magnetron heating system112and/or transformer tanks154. The returning air is first conditioned by picking up heat from the magnetron heat exchanger168, and thereafter, recovering heat from the transformer heat exchanger180. The internally conditioned return air passed through the liquid to air heat exchanger124and is discharged through the air outlet104. By the use of the magnetron heat exchanger168and transformer heat exchanger180, the heat from operation of the transformers and magnetrons are dissipated directly into the path of the return air. The recovered heat from the aforementioned heat exchangers is directed into the airflow of the forced air through the air outlet104by means of the blower188. The heating system100utilizes all consequential heat generated by the system components.

Referring toFIGS. 9 and 10, another embodiment of the present invention is described incorporating a forced air regeneration system. One principal of forced air regeneration is to return a portion of the outlet hot air through the return air inlet106using temperature controlled baffles or dampers. This approach decreases the time required to preheat the heating system100to operating temperature. In addition, it allows the heating system to maintain a higher temperature at the air outlet104during operation by approximately 10 degrees Fahrenheit or higher in accordance with one embodiment.

The forced air regeneration system includes a regenerative heat recovery duct194. The duct194includes a return air inlet196having an opening controlled by the dampers186via a servo control unit198. The duct194is mounted to the housing102with air inlet196arranged in alignment with air inlet106for controlling the return air to the heating system100. The duct194has an air inlet200arranged at its upper end in communication with the interior of the housing102and an air outlet202also in communication with the interior of the housing via air inlet106. Regenerative heat directed into the air inlet200from within the housing102passes through the duct194and is discharged into the cold air return by air outlet202. As previously described, the cold air return through the air inlets106,196is controlled by the temperature controlled dampers186.

The heat regeneration system described above thus directs a portion of the outlet heat back to the cold air return. This system uses the butterfly dampers186in the cold air return which are controlled by heat sensors located in the cooling and/or returned liquid from the liquid to air heat exchanger124. When the system requires more preheated air, the dampers186restrict cold air return to draw more heated air into the system. This system yields approximately a 10 degree Fahrenheit increase in outlet temperature. This will maintain an outlet temperature of about 150 degrees Fahrenheit with a liquid to air heat exchanger124temperature of about 140 degrees Fahrenheit.

By combining the magnetron heating system112and the cooling and heat recovery systems162in a sealed housing102, this provides a heat retention system which allows the heating system100to operate using minimum power. The heating system100is controlled by a microprocessor that constantly monitors all operating parameters of the heating system to maximize efficiency under all conditions. In operation, the heat recovery system directs the heat removed by the magnetron cooling system164and transformer cooling system166into the warm airflow of the heating system100, prior to the liquid to air heat exchanger124. This process recovers approximately 95 percent of the power lost to heat.

The heat retention system, which includes the magnetron cooling system164and the transformer cooling system166, is maintained at approximately 200 degrees Fahrenheit during operation. Upon restart at the next heating cycle, the oil within the heat retention system will be at least approximately 180 degrees Fahrenheit. The maintained heat is immediately directed back into the warm airflow of the heating system100. This provides rapid return to operating temperature at the next start up.

The overall effect of the heating system100in accordance with the present invention is increased efficiency and comfort control of the heated area. This can be achieved by incorporating a number of the above described features of the present invention.