Patent Application
20240044560
The present invention relates generally to a refrigeration or heat pump systems and its defrosting process. More specifically, a higher efficiency refrigeration & heat pump systems with on demand vibrational deicing technology.
The lead inventor, invented the direct contact ultrasonic drying at the time he worked at Oak Ridge National Laboratory (ORNL) and launched Ultrasonic Technology Solutions, a startup company, back in 2018. Ultrasonic Technology Solutions, an ORNL spinoff company specialized in the wide applications of ultrasonic transducers and other various vibrational technologies.
Unlike the conventional systems, the proposed advanced vibrational deicing process uses no or low heat for defrosting. Instead, it uses the micro vibrations imposed by vibrational mechanisms such as piezoelectric transducers to mechanically break ice from the heat exchanger almost instantaneously. The technology offers the potential of significant energy savings by eliminating the defrost cycle, improving the system demand responsiveness, sensing on-board frost thickness, reducing fan power, and subcooling the liquid refrigerant, as well as increasing the refrigeration cycle performance by reducing the temperature lift required between evaporator and the air. The technology will also significantly improve the product/food quality by minimizing or eliminating the temperature swing in the refrigeration & heat pump systems/freezer, retaining the quality of the stored frozen food, a major non-energy benefit.
A refrigeration or a heat pumping system is disclosed. The refrigeration system comprises a heat exchanger; one or more vibration systems attached to the heat exchanger;
an amplifier connected to one or more vibration systems; and a plurality of sensors attached to the heat exchanger.
In one embodiment, the present invention can include a motor vibration system.
In some embodiments, the present invention can include a magnetic vibration. system,
In some embodiments, the present invention can include a piezoelectric vibration,
In some other embodiments, the present invention can include a fin vibration system.
In yet some other embodiments, the present invention can include a hammer vibration.
All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.
As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art that the present disclosure has broad utility and application. As should be understood, any embodiment may incorporate only one or a plurality of the above-disclosed aspects of the disclosure and may further incorporate only one or a plurality of the above-disclosed features. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the embodiments of the present disclosure. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present disclosure.
Accordingly, while embodiments are described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present disclosure and are made merely for the purposes of providing a full and enabling disclosure. The detailed disclosure herein of one or more embodiments is not intended, nor is to be construed, to limit the scope of patent protection afforded in any claim of a patent issuing here from, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself. Accordingly, it is intended that the scope of patent protection is to be defined by the issued claim(s) rather than the description set forth herein.
Additionally, it is important to note that each term used herein refers to that which an ordinary artisan would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein—as understood by the ordinary artisan based on the contextual use of such term—differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the ordinary artisan should prevail.
Furthermore, it is important to note that, as used herein, “a” and “an” each generally denotes “at least one,” but does not exclude a plurality unless the contextual use dictates otherwise. When used herein to join a list of items, “or” denotes “at least one of the items,” but does not exclude a plurality of items of the list. Finally, when used herein to join a list of items, “and” denotes “all of the items of the list.”
A single-layer piezoelectric transducer, which can be as low in cost as a few cents when bought in bulk, can have an extremely small footprint, and be attached to thin sheets of metal like those used for evaporator fins. When powered by an alternating voltage at the resonance frequency of assembly, it can generate a powerful sub-micron vibration distributed along the sheet metal. When using many simplified assumptions, the wave propagation along the sheet metal (fins) can be estimated by the Bessel functions. These micro-vibrations can break the ice crystals. The ice debris formed in this process can be stored and used to precool the incoming water to the icemaker machine during the peak time, reducing both energies required for icemaking and making the system demand responsive.
According to a study done by NIST, icemaking can increase the refrigeration & heat pump systems energy consumption by 12-20%. The proposed technology not only reduces the defrosting energy but also reduces the icemaking energy requirements. In addition, the mechanical vibrational deicing enables the refrigeration & heat pump systems to be responsive to the grid signals (if/when available) and perform the deicing instantaneously during the low demand times. In commercial refrigeration applications, the mechanically removed ice can not only reduce the defrosting energy, but also the broken ice crystals can be used for refrigerant subcooling. Also, due to minimum or no thermal swing during the deicing process, the improved food storage quality is another non-energy benefit of the technology.
The resonance frequency of the piezo changes with loading amount (i.e. the higher the frost mass, m, the lower the resonance frequency, f→f˜√(k/m).) During the preliminary experiment, we have already seen a significant shift in the resonance frequency of the piezo (measured by an impedance analyzer) as frost built up on the metal sheet. Such critical information could make the defrosting process smarter and more demand responsive.
The third innovation involves our proprietary, low cost, high efficiency, flexible amplifier that has a very small footprint. The amplifier not only can power the piezoelectric transducers, but also it can be made to send unique pulses to the piezos and interpret the feedback. Based on the feedback from the piezos, it can understand the state of the piezoelectric transducers (i.e. frost loading on the piezo). This feature makes it very compatible with demand response and can be blended with artificial intelligence (AI) software. Under this patent, we have developed the hardware and platform that can do the deicing efficiently and provide signals associated with ice thickness, and all of this will be done on a microcontroller and platform that will be easily upgraded for those AI applications (if/when needed).
In one configuration, the technology may use other vibration generation mechanisms to introduce vibration to the heat exchanger or fins. These include and are not limited to high-speed motors with off-balance mass, stacks of piezoelectric elements, magnetic vibration generators or any variations of these.
As shown in the
In some embodiments, the sensors 30 can be communicatively connected to a user device. The user device can be a smart phone or other similar device that can display the control data.
The modal analysis conducted using a finite element method indicated that the lower modal resonance frequencies of various sections within the heat exchanger can range from 20 Hz to 10 kHz. In particular, when defrosting the heat exchanger fins, the required frequency may fall within the range of 30 Hz to 8 kHz. The higher modal resonance frequencies can be also used depending on the application.
In one configuration, the present invention may include a motor vibration system 20 which includes one or multiple motors with eccentric mass can be mounted on the rigid parts of the heat exchanger 60. When the combination of the RPM and when the eccentric mass is spun at a specific RPM, the force applied to the refrigeration & heat pump system 100 causes frost to break off of the fin surface.
In another embodiment, the present invention may include a magnetic vibration system 20 by which the vibration can be induced by a magnetic generator or speakers. These devices use magnetic fields to induce force to a ferrite material to apply alternating force on an object. These magnetic vibration systems 20 are well-suited for higher-frequency applications.
In another embodiment, the present invention may include a piezoelectric vibration system 20 by which piezoelectric transducers can induce vibration on the heat exchanger or the fins. When a single stack of piezo electric transducers is placed under the heat exchanger's mounting points or on the fixed side walls or directly on the fins, the generated frequency can be tuned to apply enough amplitude at a specific frequency to break ice crystals mechanically.
In another embodiment, the present invention may include a fin vibration system 40 by which the vibration on the fin can be applied by sliding flicker pins or brushes to gently penetrate between two adjacent fins so that when they move, like a guitar string. To eliminate the fin damage through this process, the fin and flicker material can be made of compatible material. For the full-size heat exchanger, this mechanism may include a wiper-type slider with an actuator activated at certain intervals.
In the last embodiment, the present invention may include a hammer vibration 20 system by which the vibration can be introduced by hitting an object to the side of the heat exchanger. This hammer-like mechanism can be motivated by a magnetic drive or piezoelectric drive system or motor driven. In this configuration, the applied impulse force is equal to a change in the momentum of an object divided by the duration of impact.
The amplifier portion 10 of the product may include a high-current AC voltage generator with current sensing operated by an intelligent controller. The vibration systems (20, 40, 50) can be driven at fixed AC voltage, with current measured. The operating frequency is varied to maximize this current, with the assumption that maximum current draw occurs at mechanical resonance.
The proposed technology is totally new in terms of how ice can be removed from the surface. Unlike the conventional passive solutions, our active non-thermal solution will utilize our recent discovery of micro-vibrational ice crystal breaking and apply it to the defrosting process. This active solution will significantly improve the efficiency and at the same time the demand responsiveness of the refrigeration cycles. Also, we propose to collect cold frost particles to sub-cool the refrigerant leaving the condenser.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63370611 | Aug 2022 | US |
