Infrared water heater

Water heaters are disclosed having first and second fluid conduits, where the second fluid conduit is fluidly coupled to and disposed about at least a portion of the first conduit. One or more heating device, and preferably an infrared light source, can be disposed between the first and second conduits, such that water flowing within the conduits can be heated by the heating device.

FIELD OF THE INVENTION

The field of the invention is water heaters.

BACKGROUND

In the United States, water heaters traditionally have a tank configured to hold a quantity of heated water. Tanked water heaters are advantageous in that they can provide a relatively large volume of hot water from a relatively tow level energy source, but they are inefficient in that they maintain a supply of hot water even when such water is not being used. Such water heaters are also problematic in that they can therefore “run out of hot water” from time to time. Still further such traditional tank heaters can pose a danger of explosion if the relief valve fails due to limestone, calcium or other deposits.

One solution is to use a tankless water heater that heats water on demand. Tankless water heaters are known that use resistance heating, and heating via infrared radiation. An exemplary embodiment of an infrared (IR) water heater is described in U.S. Pat. No. 4,510,890 to Cowan, which uses IR radiation to cause combustion of an air/gas mixture that can be used to heat water in a tank. Such a configuration is disadvantageous because the IR radiation is used to combust the mixture, rather than heat the water directly. That leads to inefficiencies, and moreover the combustion of the mixture is a potential danger.

Cowan and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

Another known infrared water heater device is described in EPO patent no. 279767 to Ripka, et al. However, the Ripka heater is disadvantageous as it utilizes a portion of the heat produced as a space heater rather than concentrate the infrared radiation on the piping. U.S. Pat. No. 5,685,997 to LoPresti discusses a plasma oscillator water heater that uses a hollow chamber to heat water outside of the chamber, but such heater is impractical for residential needs, and fails to utilize an infrared light source. Still further devices are described in U.S. pat. pub. no. 2011/0058797 to Servidio (publ. Mar. 2011) and U.S. pat. publ. no. 2012/0080422 to Chung et al. (Publ. Apr. 2012), each of which suffers from one or more disadvantages.

It is also known for a water heater to use the sun as its source of heating energy. For example, U.S. patent appl. no. 2010/0192944 to Gruber discusses a solar water heater and distiller device having multiple lenses arranged on the external wall through which IR radiation can pass. In another design, U.S. Pat. No. 4,334,522 to Dukess discusses a spherical solar energy device through which IR radiation from the sun can pass and be directed onto an inner member's surface. These solar water heaters each suffer from one or more disadvantages including, for example, a dependency upon solar energy and an inefficient use of IR radiation.

Thus, there is still a need for improved water heaters having multiple fluid conduits that are disposed about one or more heating devices.

SUMMARY OF THE INVENTION

The inventive subject matter provides apparatus, systems and methods in which one can heat water using infrared radiation or other heating devices. In especially preferred embodiments, a water heating device can include first and second fluid conduits that are fluidly coupled, where the second fluid conduit can be disposed about at least a portion of the first fluid conduit. A heating device, which preferably comprises an infrared light source, can be disposed between the first and second fluid conduits, such that water flowing within the first and second conduits can be heated by the radiation from the heating device.

In other contemplated embodiments, a water heating device can include a housing having a top, a bottom, and at least one side wall, which collectively define a heating chamber. An infrared light source configured to produce infrared radiation can be disposed within the heating chamber. A coiled conduit can be disposed within the heating chamber at least partially about the first infrared light source such that at least eighty percent, and more preferably ninety percent, of the infrared radiation directly impinges upon the first coiled pipe.

DETAILED DESCRIPTION

One should appreciate that the disclosed techniques provide many advantageous technical effects including reducing the required energy and time necessary to heat water relative to traditional water heaters, while preventing contact of the heating device with water to thereby reduce and preferably eliminate the risk of shortages, as well as fouling, in the water heater.

InFIGS. 1A-1D, a water heater100is shown having an inlet conduit102and an outlet conduit104. The water heater100further comprises a housing106, which preferably covers a heating device within the water heater100and prevents unauthorized or unintentional access to the internal components of the water heater100. Water heater100can include a valve114configured to regulate the flow of water exiting conduit104. Any commercially suitable valve could be used including, for example, gate valves, ball valves, solenoid valves, and check valves.

The water heater100can optionally include a thermostat108and thermometer110, which can display a temperature of water exiting water heater100. Of course, it is also contemplated that the temperature at which the water is heated by water heater100could be remotely controlled via a wired or wireless network. In some embodiments, the power supplied to the water heater100can be varied depending upon the temperature of the water feed through the inlet conduit102, the flow rate of the water through the water heater100, and the desired temperature of the water exiting water heater100.

In some contemplated embodiments, the water feed can comprise water from a city water line. In other embodiments, the water feed can comprise at least some heated water that is recirculated to water heater100.

Although water heater100is shown having a plug112capable of receiving a line voltage, it is also contemplated that water heater100could receive power from alternative sources including, for example, photovoltaic cells, a natural gas line, a battery, a generator, and any commercially suitable power source(s) and combinations thereof.

Water heater100can be sized and dimensioned for various uses including, for example, residential, commercial, and industrial uses. For example, it is contemplated that a water heater for residential uses could be sized and dimensioned such that the housing106has a volume of no more than 1 m3. Of course, the specific size and dimension of the water heater100will depend upon the amount of water to be heated in a given period of time.

FIG. 1Billustrates a vertical cross-section of the water heater100shown inFIG. 1A. Water can enter water heater100via inlet conduit102, which is fluidly coupled to a first fluid conduit120where the water can be preheated. Of course, in alternative embodiments, inlet conduit102and the first fluid conduit120could be a single piece. As shown best inFIG. 1C, the inlet conduit102and the first fluid conduit120can be coupled, and leaks can be prevented using an O-ring or other seal122, which is tightened in place via washer124and bolt126, although any commercially suitable fastener(s) could be used.

The first fluid conduit120is preferably coupled to a second fluid conduit132via junction136, and the second fluid conduit132can be fluidly coupled to outlet conduit104. In this manner, water can enter the inlet conduit102and be preheated, and then be fed through the first fluid conduit120, junction136, and the second fluid conduit132where the water is further heated before exiting water heater100via outlet conduit104. Of course, it is also contemplated that water could flow through water heater in the opposite direction. In other alternative embodiments, some or all of conduits120,132,136,102,104can be a single piece rather than separate individual components coupled together.

Water heater100can include heating device134, which preferably comprises one or more infrared bulbs or other infrared light sources. Preferred infrared heaters are configured to produce infrared radiation at a wavelength of between 1400 nm to 3300 nm. However, the specific wavelength of the radiation produced can vary, and could even include infrayellow or infrawhite radiation, for example. As shown inFIG. 1C, it is especially preferred that heating device134comprises an infrared heating coil that is at least partially disposed about the first fluid conduit120. The infrared heating coil preferably comprises a stainless steel coil, although other metals, metal composites, and/or commercially suitable material(s) could alternatively be used. In such embodiments, as water flows through the first fluid conduit120, the water can be heated by the infrared radiation impinging upon the first fluid conduit120. However, any commercially suitable heating device could be used including, for example, resistance heaters, microwave heaters, and induction heaters.

Heating device134is preferably mounted to at least one of the first fluid conduit120and inner housing130via a ceramic mounting140, although any commercially suitable material(s) could be used.

It is contemplated that the coiled fluid conduit132can include a plurality of stacked pipe segments. It is especially preferred that the spacing between adjacent pipe segments is less than 3 cm, although spacing greater or equal to 3 cm are also contemplated. The coiled fluid conduit132preferably comprises copper, although any commercially suitable material(s) could be used including, for example, steel and other metals and metal composites. In especially preferred embodiments, the coiled fluid conduit132is disposed about heating device134such that at least eighty percent, and more preferably, at least eighty-five percent, of the infrared radiation directly impinges upon the coiled fluid conduit132. Such an arrangement advantageously allows the conduit132to absorb a large amount of heat produced by the heating device134, such that the water flowing through conduit132can quickly be heated without a significant heating delay.

In some contemplated embodiments, the coiled fluid conduit132can include first, second, and third conduit segments, and the heating device134can include first, second, and third filament segments. In such embodiments, it is especially preferred that the first conduit segment and the first light filament be disposed at substantially the same “level” or height within the inner housing130. In this manner, radiation emitted by each of the filament segments can be absorbed by the conduit segments.

After flowing through the first fluid conduit120, water can then pass through the second fluid conduit132, which preferably comprises a coiled conduit that can be disposed about at least a portion of the heating device134. As water passes through the second fluid conduit132, the water can be further heated. The coiled conduit132significantly increases the surface area of the conduit132exposed to radiation from the heating device134, and thereby increases the amount of time the water is exposed to heat energy from the heating device134while in the water heater100. It is especially preferred that adjacent coils of the coiled conduit132abut one another, such that a primary heat shield can be formed about heating device134to thereby trap heat within the volume defined by conduit132.

Contrary to prior art devices, the heating device134can be disposed between the first and second fluid conduits120,132, such that the radiation or other heat energy from the heating device134can be absorbed by both the first and second fluid conduits120,132. This advantageously reduces the required output and energy requirement of the heating device134due to the close proximity of both the first and second fluid conduits120,132.

It is contemplated in such an arrangement that water entering the water heater100at a temperature of about 60° F. (15.6° C.) could be heated to a temperature of about 100-120° F. (37.8-48,9° C.) as it travels through and exits from the water heater100. This advantageously allows the water to be quickly heated on-demand as it travels through the water heater100, while using only a fraction of the energy required by conventional water heaters. In some contemplated embodiments, the water heater requires 1 KW of energy or less.

Water heater100can further include an inner housing130that preferably encloses the first fluid conduit120, the second fluid conduit132and heating device134. The inner and outer housings130,106can be composed of any commercially-suitable material(s) including, for example, stainless steel and other metals, metal composites, and any combination thereof. As shown inFIG. 1D, water heater100can include a top106A, bottom106B, and at least one side wall106C, which can collectively define housing106.

Thus, water can be initially heated as it travels through the first fluid conduit120, and can be further heated as it travels through the second fluid conduit132. In this manner, water received by the water heater100could be heated to a temperature of 80° F. (26.67 degree Celsius) or greater when the water exits the water heater100. Depending upon the specific water temperature required or desired, the flow rate of the water could be increased or decreased as necessary to achieve the desired temperature. In addition, it is contemplated that the water heater100could include a second inner housing (not shown) comprising a second heating device and fluids conduit(s), such that the heated water from second fluid conduit132can flow into the second inner housing and be further heated by the second heating device. Although the conduits and other components within the second chamber could be arranged identically to those within inner housing130, it is alternatively contemplated that the second inner housing could comprise a different arrangement and/or have different components than that within the inner housing130.

It is further contemplated that the water heater100could comprise a second heating device (not shown) that is disposed within the inner housing130. For example, the second heating device could be disposed within or about at least a portion of the first fluid conduit120, or elsewhere within the inner housing130. The second heating device could comprise any commercially suitable heating device including, for example, an infrared heater, a resistance heater, and an induction heater.

Water heater100can further include a pressure switch or other monitor, such that a pressure within the outlet conduit104can be monitored. If the pressure increases above a predetermined threshold, it is contemplated that power or other energy to the water heater100could be slut off to prevent risk of an explosion. Although not shown, it is also contemplated that water heater100could include a pressure relief valve.

By having water first flow in one direction through inner housing130and then flow in the opposite direction, the overall size of the inner housing130and the water heater100can advantageously be minimized.

Conduits120and132each preferably comprises copper because of its conductive properties, although any commercially suitable metals or metal composites or other non-insulative material(s) could be used. It is further contemplated that conduits102,104and136could comprise stainless steel or any other commercially suitable material(s). In some contemplated embodiments, conduits102,104and136could be insulated to prevent heat loss.

In an exemplary embodiment, the heating device134could require 4 KW of energy to heat water having an initial temperature of 12° C. and flowing through the water heater100at a rate of approximately 70 ml/s to a temperature of approximately 32° C. when the water exits the water heater100. In such embodiment, it is contemplated that the temperature of the water exiting the water heater100could be increased by (a) decreasing the flow rate of the water through the water heater100, (b) fluidly coupling inner housing130to a second inner housing having a second heating device, or (c) adding a second heating device within conduit120, for example. It is also contemplated that by reducing the flow rate of the water in the above example to approximately 40 ml/s, the temperature of the water exiting the water heater100could be increased to approximately 47° C.

FIGS. 2A-2Billustrate another embodiment of a water heater200. It is contemplated that a temperature of the water at outlet conduit204can be between 25° C. to 160° C., and more preferably between 70° C. to 130° C. In this manner, a temperature gradient between the feed water at inlet conduit202and the heated water at outlet conduit204can be at least 10° C., more preferably, at least 15° C., at least 20° C., and at least 40° C., and still more preferably at least 60° C., and even at least 80° C. With respect to the remaining numerals in each ofFIGS. 2A-2B, the same considerations for like components with like numerals ofFIG. 1Bapply.

InFIG. 3, a coiled conduit332is shown having a series of coiled segments333, which abut adjacent segments to form a primary heat shield.FIGS. 4A-4Billustrates an alternative embodiment of the first fluid conduit420having multiple fluid passages421within the conduit420.

FIGS. 5A-5Cillustrate a fluid conduit520having a second heating device560disposed within the fluid conduit520. The second heating device560could be spaced apart from a surface of the conduit520via spacers562. In this manner, water can be exposed to additional heat energy as it flows through the conduit520. The second heating device560preferably comprises an induction heating device, which advantageously reduces the possibility of a short due to water contacting an electrical circuit of the heating device560. However, it is alternatively contemplated that the second heating device560could comprise a resistance heater, an infrared heater, or any other commercially suitable heating device.

InFIG. 6, a horizontal cross-section of another embodiment of a water heater600is shown having a housing630, in which an inner fluid conduit620and an outer fluid conduit632can be disposed. Although shown having a cylindrical cross-section, housing630could comprise any commercially suitable shape such as a square, rectangle, oval, and so forth. The outer fluid conduit632can be disposed about at least a portion of the inner fluid conduit620, and is preferably a coiled conduit to thereby increase the surface area of the conduit exposed to heating device634.

Heating device634is preferably disposed between the inner and outer fluid conduits620,632, which reduces the distance between the heating element(s) of device634and the fluid conduits620,632and thereby increases the efficiency of the water heater600. Although shown as comprising four infrared bulbs635, it is contemplated that heating device634could comprise fewer or a greater number of infrared bulbs depending upon the desired temperature of the water, the rate at which the water is to be heated, the size of the water heater600, and so forth. Alternatively, heating device634could comprise a coiled filament configured to produce infrared radiation, or any other commercially suitable heating element.

The bulbs635are preferably configured to produce infrared radiation having a predominant wavelength of between 2500 to 3500 nm and more preferably of between 2700 to 3300 nm. All suitable infrared light sources are contemplated, including especially tubular bulbs, such as the Sylvania® 59934 special stranded LDS Base 3,000 K clear infrared double ended quartz halogen (1200T3Q/IR/CL/HT 144V). Another suitable choice is a Philips® 312678 1,000 watt 235 volt T3 Z Base 2,450K clear reflector industrial infrared quartz halogen (13713Z/98 1000W 235V).

In especially preferred embodiments, the coiled fluid conduit632is disposed about the infrared bulbs635such that at least eighty percent, and preferably at least eighty-five percent, and more preferably at least ninety percent, of the infrared radiation directly impinges upon the inner and outer fluid conduits620,632.

FIG. 7illustrates a horizontal cross-section of yet another embodiment of a water heater700. Water heater700can include a housing730, in which an inner fluid conduit720, a heating device734, and an outer fluid conduit732can be disposed. Preferably, the heating device734comprises a coiled filament configured to produce infrared radiation and thereby heat the neighboring inner and outer fluid conduits720,732. By disposing the heating device between the inner and outer fluid conduits720,732, the fluid conduits are advantageously exposed to nearly all of the infrared radiation produced by the heating device734.

The outer conduit732can comprise a series of parallel conduits disposed about the heating device734and substantially parallel to the inner conduit720, through which water can flow back and forth through the chamber into and out from the page as shown inFIG. 7). In other embodiments, the outer conduit could comprise a coiled conduit such as that shown inFIG. 6.