Patent Application
20210372638
The invention relates broadly to forced air heating, ventilation and air conditioning (HVAC) systems, and more particularly relates to an air to air heating system and method that rely upon carbon nano tubes (CNTs), manufactured through chemical vapor deposition (CVD) process, and preferably including MgSO4 or MgO, to generate heat in lieu of conventional resistance heater coils, resulting in and efficiency increase of 2.6 to 3.4 times that of conventional HVAC systems, which rely on conventional heater coils.
Many HVAC systems include a heat pump. Simply, a heat pump uses a refrigeration cycle to move heat energy from a first environment to a second environment. The device is called a “heat pump” because the temperature of the first environment is lower than the temperature of the second environment, and so the natural direction of heat transfer would be from the second environment to the first environment. The heat pump reverses this natural flow of heat by “pumping the heat energy from a colder, first environment to a warmer, second environment. As long as there is at least some energy in the first environment, and an appropriate heat transfer fluid is selected, it is possible to transfer heat against the natural direction of heat transfer.
The advantage of using a heat pump is that it allows a heating system to rely upon and consume less energy from an external energy source to perform the heat transfer process than would be used to directly heat the first environment. For example, if electricity is used to operate a heat pump to heat a first space, and the alternative is to heat the space with an efficient electrical heater, then the heating system comprising the heat pump will typically consume less energy to directly heat the space than with a conventional heating system using a conventional electrical heater. A heat pump can be an attractive source of heating and cooling an indoor environmental space where the outdoor temperature does not reach extreme lows in the winter, and where the cost of electrical energy (used to operate a compressor and a fan in the heat pump) is not too high. For that matter, when the cost of electricity becomes very high, then heating with natural gas may be a more economical alternative. However, where natural gas is not available (for example, in a rural or a remote setting), then a heat pump is an attractive source of environmental heating and cooling even where the cost of electricity is relatively high.
Heat pumps are typically configured to operate in one of two modes: a summer mode and a winter mode. (These modes are alternately, and respectively, known as “cooling mode” and “heating mode”.) In the winter mode, the heat pump moves energy from a source of energy to an indoor environment, such as a residence or a commercial building. In the summer mode, the heat pump moves energy from the indoor environment to another location. Many heat pumps are configured to be able to switch from one mode to the other. Thus, the heat pump can act to heat an indoor environment in the winter and cool the same indoor environment in the summer.
Known sources of energy that can be accessed by the heat pump for winter mode include solar heat, ground or earth heat, ambient air, water (such as a river), and waste heat. Waste heat is more common in an industrial environment where heat from commercial processes (such as incineration) can be accessed. If the heat pump is to be used in the summer mode, then the objective becomes locating a destination to which heat from the indoor environment can be transferred. Obviously, for winter mode it is preferable to locate a source of energy having a large amount of available energy, such as solar energy. For summer mode, it is preferable to identify a location to which the indoor heat can be pumped which is relatively cool and will thus accept a large amount of heat. If the heat pump is configured to switch between modes, then it is preferable to locate a source that can provide heat for the winter mode yet accept heat in the summer mode. The most common source is to use the outside ambient (or atmospheric) air. In this case, the heat pump is known as an air-to-air heat pump since it moves heat between the air in the indoor environment and the air in the outdoor atmosphere.
U.S. Pat. No. 6,615,602 to Wilkinson, for example, discloses a heat pump with supplemental heat source. The heat pump includes a compressor, indoor heat exchanger, outdoor heat exchanger, outdoor thermal expansion valve and an auxiliary heat exchanger. An auxiliary fluid line and an auxiliary fluid pump circulate an auxiliary heat transfer fluid through the auxiliary fluid line, where the auxiliary heat exchanger exchanges heat between the refrigerant fluid and the auxiliary heat transfer fluid. The auxiliary fluid line is in thermal energy communication with a primary source of auxiliary heat. Preferably, the primary source of auxiliary heat is a fluid contained within a septic tank or like fluid storage space or volume available.
Also known are carbon nanotubes (CNTs). Carbon nanotube (CNT) are tubular structure made of carbon atoms, having diameter of nanometer order but length in micrometers. CNTs are many-fold stronger than steel, harder than diamond, display electrical conductivity higher than copper, and thermal conductivity higher than diamond, etc. CNTs have been found to possess a number of extraordinary properties, offering new capabilities and performance beyond the possibilities of heretofore known materials. For technological applications, especially in electronics, the prospects of carbon nanotubes are further enhanced by excellent thermal properties.
CNTs are stable at up to 2800° C. in vacuum and 750° C. in air, comparable to the 600° C. to 1,000° C. melting range of metal wires in microchips. More impressively, CNTs also display some of the best thermal conductivity. Single-walled carbon nanotubes exhibit a heat-transmission rate ranging from 1750 to 5800 W·m-1·K-1, and multiwalled carbon nanotubes show a rate of 3000 W·m-1·K-1. This is similar to, or better than, the best quality diamond's heat transfer rate of 3320 W·m-1·K-1, and up to a factor of 15 higher than the 385 W·m-1·K-1 of copper, one of the better heat conductors commonly used in current electronics. Thus, carbon nanotubes could support much denser (i.e. faster) circuits than the present edge of microprocessor technology.
Chemical vapor deposition (CVD) is the most popular method of producing CNT's nowadays. In this process, thermal decomposition of a hydrocarbon vapor is achieved in the presence of a metal catalyst. Hence, it is also known as thermal CVD or catalytic CVD (to distinguish it from many other kinds of CVD used for various purposes).
Traditional heating products are known to be inefficient and costly to run, comparatively, and require a significant amount of time to radiate sufficient heat for the space heated thereby to reach the desired level of comfort. This is because traditional heating products heat via convection, which works by heating the air around you. But an addition of CNT sheets to commonly deployed carbon fiber composite structures increases conductivity by an order of magnitude, and a 3-5 time increase in stiffness over aluminum core along with outstanding near-zero coefficient of thermal expansion (CTE) performance—all with reduced weight and improved mechanical damping.
In addition, CNT heating elements offer a high-efficiency heating solution without the limitations of conventional materials which require elements to be heated to very high temperatures to allow effective heating at a distance. CNT heating elements are manufactured via chemical vapor deposition into the final product format, eliminating the need for binders or secondary processing steps. They are composed of bundled CNTs hundreds of microns thick and millimeters long. CNT heating elements utilize far infrared energy (FIR), which as a result, imparts warmth more quickly than heating elements formed without.
The present invention overcomes the shortcomings of the prior art.
In an embodiment, the invention provides a thermo-electric heating assembly for forced air, residential and commercial heating, ventilation and air conditioning (HVAC) systems. The heating assembly comprises a housing, a controller and a plurality of carbon nanotube (CNT) heating elements, arranged in the housing. The controller is adapted to respond to a signal received by the controller indicating a need for heat by powering the carbon nanotube (CNT) heating elements at a controlled electrical power level for a controlled period, commensurate with the indicated need for heat.
Each of the plurality of CNT heating elements comprises: an upper metallic heat dispersion vein/radiator; a first composite containment vessel; a first layer of 3D CNT graphene film consisting of 2 separate strips of 3D CNT graphene films; a second composite containment vessel; and a lower metallic heat dispersing vein/radiator. The CNT heating elements may further comprise a third composite containment vessel and a layer of MgSO4 or MgO is arranged between the third composite containment vessel and the lower metallic heat dispersing vein/radiator. Preferably, the first and second composite containment vessels are formed from high-temperature resistant, electrically non-conductive, and highly heat conductive prepregs.
In an embodiment, the invention provides a kit for replacing a heating assembly positioned in a plenum, or proximate a plenum, of a forced air, residential and commercial heating, ventilation and air conditioning (HVAC) system. The kit comprises a thermo-electric heating assembly and wires, connected at one end to the thermo-electric heating assembly, for connecting at another end to a control panel of the HVAC system. The thermo-electric heating assembly comprises a housing, a controller and a plurality of carbon nanotube (CNT) heating elements, arranged in the housing. The controller is adapted to respond to a signal received by the controller indicating a need for heat by powering the carbon nanotube (CNT) heating elements at a controlled electrical power level for a controlled period, commensurate with the indicated need for heat.
The inventive thermo electric heating assemblies for forced air, residential and commercial HVAC systems furnaces, powered by CVD-derived carbon nanotubes (CNTs), may be included in new constructions, but is particularly suited to retrofitting into existing HVAC systems, replacing the heating coils therein. Replacing auxiliary electrical resistance heaters, known as “strip heaters,” with an inventive heating assembly with realize a drastic reduction in energy consumption, compared to 6 existing commonly used heating systems.
Essentially, the inventive heating assembly provides a very efficient way of production and is superior in design and economy as a producer of heat compared to nichrome/kanthal heater elements, natural/propane gas, conventional electrically powered metallic heating elements, Boiler and Geothermal Heat pump systems.
For that matter, because of the characterizes associated with CNT's, the inventive heating assemblies formed therewith are physically stronger and much more durable and reliable than current heating elements. This greatly increases service life and reduces maintenance. And the energy savings defines products created with the inventive heating assemblies green technology. CNT technology is environmentally friendly; no greenhouse gases are released in either their production or use, nor with their use produce significant carbon monoxide or carbon-fluoro-carbon gasses.
With the above and other objects in view, this invention consists of the combination and arrangement of parts more fully described and illustrated in the accompanying drawings and more particularly pointed out in the claims, it being understood that changes may be made in the form, size, proportions and minor details of construction without departing from the intent of the design or sacrificing any of the advantages of the invention.
The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The example embodiments are presented in such detail as to clearly communicate the invention and are designed to make such embodiments obvious to a person of ordinary skill in the art. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention, as defined by the appended claims.
The return air duct directs non-conditioned ambient temperature air through the air-filter from the interior of the house, initiated from the blower, which pulls filtered air through the A-frame/evaporator coil and pushes it through the 3D CNT heating assembly thus forcing the conditioned and heated air into the plenum and from there, through the entire interior residential space. That is, air from the lower/2nd compartment passes through the upper/1st compartment 3D CNT heating assembly 130, is heated therein and dispersed to its final destination. This simple design, and steps for heating and delivering air in reliance upon the inventive structural arrangement, eliminate the need to use a more costly refrigeration cycle to move heat energy from a first environment (exterior) to a second environment (interior), i.e., a heat pump.
Such an inventive system also eliminates a need to supplement the heat pump therein with emergency heat strips, thus lowering the manufacturing costs, operating costs, maintenance costs and need for added equipment costs such as humidifiers. In the case where a retrofit would be more practical, energy reduction is achieved according to the invention by simply removing the existing emergency heating strips (as the case may be) and disabling the reversing valve in the heating portion of the conventional heat pump and inserting an inventive 3D CNT Heating assembly, such as heating assembly 130 into the cavity vacated by the Emergency Heating Strips. In the retrofit, the existing wiring and control panel may be utilized without concern for current overload as the 3D CNT heating assembly uses 72% less current than the emergency heating strips. This reduction along with an added 72% reduction in energy consumption from the Heat Pump delivers a substantial reduction in energy consumption.
It should be noted that these improvements were achieved without the added layer of MgSO4 or MgO to the 3D CNT heating assembly, such as in the alternative embodiment heating assembly depicted in
The CNT heating assembly 130 is depicted in detail in
The embodiment depicted in
Leveraging the MgSO4 135h would take the efficiency savings from 72% to 89% compared to a standard heat pump. Table I below is a comparison of heat storage methods and materials that are relevant to the invention.
The assembly process of the CNT graphene heating element 134 (
This sub-assembly is next placed between metallic mandrels and cooked per the composite manufacturer's requirements. Once cooked, the sub-assembly is hermitically sealed. As such, along with ensuring no contaminates have been introduced, the heating element assemblies are expected to have very long life cycles. The final step is to sandwich the composite prepreg sub-assembly between the upper metallic heat dispersion vein/radiator 135a and the lower metallic heat dispersion vein/radiator 135g completing the 3D CNT graphene heating element 134. Once complete, the assembly process can be executed per instructions provided in
The process of forming the graphene heating element 136 is substantially similar to that of graphene heating element 134, except for the additional step or act of adding a layer of MgSO4 or MgO 135h, followed by another layer of composite prepreg 135b, as described in
Resistance (R) of 3D CNT film: determined by l/w where l=length and w=width Example: a sheet of 3D CNT film is 10″×1″;
R=10/1=10 and Predicted Temp C°@100V=(Ai*IP1)+IP2
100V/10R=I or I=10
Predicted Temp C°=(Ai*IP1)+IP2=((10/1)*IP1)+IPz=IP3 C°
In conclusion the 3D CNT graphene film 135f can be configured to control the exact Volts and Amps desired to achieve a specific temperature. A controller would be configured that would regulate/deliver this exact amount of Voltage and Amperage. In this example it would be 100V and 10 amps or 1000 watts.
The person of ordinary skill in the art should recognize that if a 2nd layer of 3D CNT graphene film 135f were laid out in parallel with a sheet of composite containment vessel 135b between/separating the layers of 3D CNT graphene film the configuration would now change to length/width as 10/2. As should be clear, the length is not affected because the 3D CNT graphene film is connected together by an equal set of copper wires and busses. Only the width is impacted, which would lower the resistance to 10/2 or 5. The same formula would apply but with a different resistance and a different value for Ai, thus changing the results. In the case of the prototype described, applicants have 11 sets of 134, 136 assemblies, which would change w (width) by 11 times, l (length) would remain the same. Ultimately the possibilities are infinite depending on the desired result.
While the exemplary embodiment of the CNT heating elements reflect an upper metallic heat dispersion vein/radiator, a first composite containment vessel, a first layer of 3D CNT graphene film consisting of 2 separate strips of 3D CNT graphene films, a second composite containment vessel; and a lower metallic heat dispersing vein/radiator, the invention is not limited thereto. Any number of CNT heating elements may further comprise additional composite containment vessel and respective layers of MgSO4 or MgO is arranged above and/or below the additional composite containment vessels. Preferably, the first and second composite containment vessels are formed from high-temperature resistant, electrically non-conductive, and highly heat conductive prepregs.
Retrofit
In the common occurrence where an existing residential heating system is well within the life cycle of the heating assembly therein, the inventive heating assembly 130 may easily be retrofitted into the current system, implementing savings over the existing system. The first step is to remove the current standard resistance heater coils also known as “strip heaters.” In place thereof, the 3D CNT heating assembly 130 is arranged in the cavity vacated by the standard resistance heater coils. If the 3D CNT heating assembly 130 does not fit into the existing vacant cavity, a sheet metal transition plenum can be fabricated by the installer and attached to the air handler assembly shown in
Next the reversing valve in the heating portion of the heat pump is deactivated, and the 3D CNT heating assembly 130 is connected to the controller panel on the air handler assembly (
As will be evident to persons skilled in the art, the foregoing detailed description and figures are presented as examples of the invention, and that variations are contemplated that do not depart from the fair scope of the teachings and descriptions set forth in this disclosure. The foregoing is not intended to limit what has been invented, except to the extent that the following claims so limit that.
