Patent Application
20190386195
NONE
This disclosure relates in general to liquid storage vessels and in particular to a liquid storage vessel configured to generate an electrical current.
Fluids are often stored in vessels configured to maintain a temperature differential between the fluid itself, and the ambient environment just outside the vessel. For example, it is desirable for hot coffee to be maintained at a temperature substantially above the ambient temperate outside the vessel, while iced coffee is generally maintained at a temperate substantially below the ambient temperate outside the vessel.
In general, a temperature differential is substantially maintained by configuring the vessel with an insulating material, or with an air gap, between an outer and inner surface of the vessel. However, since temperature equalization generally cannot be eliminated, it is generally considered a dead loss since it produces nothing of economic value or use.
Referring to
In view of the foregoing, it would be beneficial to take advantage of the temperature gradient between the fluid inside the vessel and the ambient environment outside the vessel, in order to generate electrical current, that may in turn, power an electrical circuit.
The invention relates, in one embodiment, to a vessel configured to generate an electrical current is disclosed. The vessel includes a reservoir configured to hold a liquid at about a first temperature, and a thermal electric module thermally coupled to the reservoir, wherein the thermal electric module is further configured to generate a first electric current. The vessel also includes a phase change material thermally coupled to the thermal electric module, the phase change material configured to absorb or release thermal energy. The vessel further includes and a temporary electrical energy storage unit electrically coupled to the thermal electric module. The vessel also includes a set of additional electric components electrically coupled to the temporary electrical energy storage unit.
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, and in which like reference numerals refer to similar elements, and in which:
The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention.
In general, the temperature of a fluid inside a vessel will tend to equalize with that of the ambient environment just outside the vessel, with the rate of equalization related to the thermal conductivity of the vessel walls. In general, this equalization is a dead loss since it does not tend to produce anything of value or use.
An electrical circuit including a TEM or thermoelectric module (also known as a thermoelectric generator) may be added to the vessel, further coupled to an energy storage medium, in order to power an electrical device, such as a light emitting diode.
However, since the amount of current generated by the TEM is relatively small, it is difficult to design a circuit configuration optimized for a very low current configuration
In an advantageous manner, an Enhanced Boost Converter may be integrated into the electrical circuit, such that the current draw of the overall circuit is minimized when engaged.
Referring to
Here, in accordance with the invention, a thermoelectric module is selected, consisting of an array of p-type 208 and n-type 210 semiconductor elements that are heavily doped with electrical carriers. In general, these elements are electrically connected in series via a set of copper conductors 206, 212, & 214, but thermally connected in parallel via a set of ceramic substrates 204 & 216, one on each side of the elements. Consequently, a Temperature differential between ceramic substrate 204 and ceramic substrate 216 causes a current to be created. In addition, the Temperature differential between 204 & 216 can be positive or negative.
In addition, in order to substantially maintain a temperature difference ceramic substrate 204 and ceramic substrate 216, a phase change material or PCM may be coupled to one surface of the TEM. In general, a PCM is a substance with a high heat of fusion which, melting and solidifying at a certain Temperature, is capable of storing and releasing large amounts of energy. Consequently, when a temperature differential between a fluid within a vessel, and the ambient temperature outside the vessel, is minimal, a greater temperature differential may still exist between ceramic substrate 204 and ceramic substrate 216, allowing a current to be generated.
Referring to
In an advantageous manner, TEM 322 is configured to be in thermal contact with both fluid 314 and PCM 320, generating an electrical current where there is a sufficient temperature differential between the two. In addition, the current may be directed to a circuit 318 to power any coupled electronic components, such as a set of diodes configured to illuminate a translucent cutout 313 of surface 306.
In one configuration, the illumination is facilitated with a light pipe configured with a set of LEDs (light-emitting diode). In general, a light pipe is an optical fiber or a solid transparent plastic rod for transmitting light from an LED to a user interface, here translucent cutout 313.
Referring to
Referring to
In an advantageous manner, thermal monitoring circuit 504 may include a thermistor, which is generally an electrical resistor whose resistance is directly affected by temperature. In a positive temperature coefficient (PTC) thermistor, resistance generally increases with increasing temperature. In a negative temperature coefficient (NTC) thermistor, resistance generally decreases with increasing temperature. Thermistors generally comprise a set of metallic oxides, pressed into a bead, disk, or cylindrical shape and then encapsulated with an impermeable material such as epoxy or glass.
The current invention is configured with a NTC thermistor, thermally coupled the outer surface of reservoir 310 (not shown), such that the temperature of the thermistor is substantially the same as that of a fluid inside reservoir 310.
The thermistor may then be powered by a small substantially constant current (thermistor current) whose voltage (thermistor voltage) is compared to a substantially fixed reference voltage using a low power comparator. In one embodiment, the thermistor current is preferably less than 700 nA. In another embodiment, the thermistor current is more preferably less than about 60 nA. In another embodiment, the thermistor current is less than about 5 nA.
When the thermistor voltage is substantially equal to the fixed reference voltage, a signal is transmitted to indicators circuit 512, which, in turn, may present to a user, visually indicia of the fluid temperature, such as a color or a set of colors. In one configuration, the visual indicia are presented through a light pipe.
In an alternate embodiment, the acoustic indicia are presented to a user.
In addition, in an advantageous manner, enhanced boost converter 517 may be used to step up the voltage (while stepping down current) from an input (supply) to an output (load). In general, an enhanced boost converter t is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element: a capacitor, inductor, or the two in combination.
In the current invention, as the voltage generated by TEM is generally very low, a boost converter may be used to charge the rechargeable battery 408 to a higher voltage and to use the stored energy at a later time. Operation of a boost converter requires turning on/off a switch. In our case a MOSFET switch is used for switching. Gate of a MOSFET acts like a capacitor and turning it ON and OFF requires charging and discharging the gate rapidly. To minimize the charge needed to operate this DC/DC converter, the control circuitry that operates the switch looks into the available charge at the input and toggles the switch according to the input voltage in a linear fashion. This input voltage in this case is the TEM voltage. As the TEM voltage drops, the control circuitry reduces the speed of the operation. When the input reaches zero, the switch stops working completely to minimize any charge waste.
The invention has been described with reference to various specific and illustrative embodiments. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.
Having disclosed exemplary embodiments and the best mode, modifications and variations may be made to the disclosed embodiments while remaining within the subject and spirit of the invention as defined by the following claims.
