Research

Below are five different articles based on research done on existing designs and patents found through the use of the web, and other media outlets.  These articles are written to show the uniqueness of our product as compared to those which currently exist physically and conceptually.  Each group member performed an analysis of existing designs and articles found, and their importance towards the design of our proposed prototype.  References for each article will be listed at the end of each segment in order of appearance in the article that precedes it.  

1)

    When researching for articles on thermoelectric materials, and cooling effects there was one article in particular that stood out.  The paper talked about the basics of thermoelectric materials and their abilities to heat or cool through a method of conduction.  The paper also talked about the problems and innovations with regards to heat transfer in thermoelectric materials.  Specifically, the article states that cooling, or heating, occurs because of differences in the coefficients known as Peltier coefficients.  These coefficients are what drives the temperature difference between the materials, and therefore cause a cooling effect.  The paper also talks about how the thermoelectric materials are non-competitive against other refrigerators such as those that are compressor based specifically.  Although this may be the case, the very nature of the coolers means that they can be developed with a compact design in mind.  With regards to our specific project, the fact that the cooler can be made compact allows for the perfect design for a stadium coaster design that does not impact space in the already tight fit that is stadium seating.  The paper also discusses the progress in thermoelectric materials, which goes on to state that Peltier cooling devices are almost based on Bi2Te3 [1].  This means that the materials are extremely costly, and a major design innovation towards the current project would be to reduce cost of materials.  One way this can be done is through “reducing both filling factor and thermoelement length” [1].  This is due to the material having two different geometries produce the same amount of electricity if the thermal and electrical resistances are the same.  

    Another article that was researched in regards to our current project was a patent on an existing design for a cup cooler made using thermoelectric materials.  It was shown by Cauchy [2] that the existing design and how it is big enough to hold the average sized drink.  The existing design also offered the ability to switch between heating and cooling the beverage.  This design will help with the development of our project as it offers a unique aspect of being able to keep beverages warm, as well as cool.  This would come in handy if the coaster were to be employed in a stadium setting where people have a slew of beverages that could range anywhere from beers to coffee, requiring both the ability to switch between hot and cold.  Taking this into consideration, the existing design of the cooler being developed can thus include some sort of method to switch between the two various methods of temperature driven gradients.  It was also shown by Cauchy [2] that the cooler has a depth to be able to support a temperature gradient through conduction on multiple sides of the beverage, not just the bottom of the container that the respective liquid is contained.  The patent also showed a convenient method of using a rocker switch to flip between the two different modes that the coaster can offer.  Below the rocker switch, there is an indicator light that shows whether there is an electrical current passing through the thermoelectric material thus meaning that the coaster is turned on and active.      All of these ideas can be taken and modified to better the development and design of our version of the coaster cooler using thermoelectric materials Patent US 2007/0033964 A1 is designed to cool beverages over a period of time. Its medium size frame favors larger beverage containers such as wine bottles etc. With the geometric shape of the device, it can only hold certain types of beverage containers. Therefore, an odd shape container would not fit in the cavity of the device. The inventor places great emphasis on alcoholic beverages like wine, which is required to be served cold to preserve its flavor. The device consists of six major sections, and one minor sub-assembly. The sub-assembly is unit 3 which consist of a power source, a small motor, and a drive member. Unit 4 is the outer cover in which is attached to unit 3. Inside of unit 4, sits unit 5. Unit 5 contains a bottle basket where it houses the beverage container. Unit 6 is the top item that enclose the device to maintain a constant temperature inside. Below, the different assemblies and sub-assemblies can be seen in figure 1.

[1] Tian, Z., Lee, S., and Chen, G., “A Comprehensive Review of Heat Transfer in Thermoelectric Materials and Devices.” [Online]. Available: https://arxiv.org/ftp/arxiv/papers/1401/1401.0749.pdf. [Accessed: 06-Feb-2018].

[2] Cauchy, C., and Miller, P., “Thermoelectric cup cooler/heater.” [Online]. Available: https://docs.google.com/viewer?url=patentimages.storage.googleapis.com/pdfs/USD500639.pdf. [Accessed: 06-Feb-2018].

2)

    The system is powered by batteries, as can be seen in figure 1. These batteries would then power the motor and spin the drive member. Attached to the drive member is the unit 5. The drive member rotates slowly inside a cooling space which consist of cooling constituents such as ice, cold water, or a cooling pad. The cooling space can be seen in figure 2 below (50).

    The article emphasizes on the different materials for thermal conduction, how materials interface, as well as high thermal conductivity materials. Heat transfer by conduction occurs when two objects at different temperature interface with each other, where heat flows from the warmer to the cooler of the objects, until both objects are at equilibrium. Examples of heat transfer by conduction are, the heat of an object from a hot plate, the operation of a heat exchanger, or even ice melting on a road way by resistance heating.

     For heat transfer by conduction to happen effectively, the materials that are interfacing with each other must have high thermal conductivity. They also have to maintain thermal contact at all times. This can be done by applying an adhesive called “thermal grease”. Thermal grease is a thermal compound that is used in high-performance electronic equipment in order to increase conductivity. This compound is placed between the mating surface of the two materials. High thermal conductivity materials are used for heating and cooling purposes, especially in the electronic industry. According to “Materials for thermal conduction” with circuit boards getting smaller but increasingly producing more power, the dissipation of heat is the main source of reliability, and performance. With the Over-heating problem lingering, the solution to this can be really expensive where conductors such as diamond, metal-matrix, and carbon-matrix [1] are being used in these microelectronic boards.

[1] Chung, D.D.L. “Materials for thermal conduction”. Applied Thermal Engineering Vol. # 21 NO. 16 (2001)https://www-sciencedirect-com.gate.lib.buffalo.edu/science/article/pii/S1359431101000424?via%3Dihub#!

[2] Huang, Kuo-Fu. “Beverage Cooling Device” Patent Application Publication, https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=2007033964A1&KC=A1&FT=D&ND=5&date=20070215&DB=EPODOC&locale=#

3)

    The article tackles harvesting residual thermal energy using phase change materials. The thermal energy storage is a placeholder that “host” residual energies gathered from hot or cold substances for further utilization. The mechanism is rather simple; it is based on the change of phase resultant from the increase in temperature. The article focuses on three main types of phase change material; the organic, inorganic and eutectic. The main advantage of using such materials lies in their chemical and thermal stability, usually being non-corrosive, recyclable and have little to none sub cooling, which means minimal waste. The thermoelectric cooling systems (Oftentimes called Peltier Cooler) are solid-state heat pumps. These type of coolers are based on the Peltier effect, discovered by Jean Peltier in 1834. The Peltier effect converts electrical energy into a temperature gradient. The method proposed is based on a paraffin grouped into active elements. The article shows that the PCM technology shows possibility of using PCMs in the active systems for heating, cooling and ventilation systems (HVAC).  After conducting various experiments, the yielded results were focused on the standard passive mode, the active cooling mode, and finally, the thermoelectric coolers powered by the photovoltaic system. Noting that the disadvantage of the thermoelectric coolers is producing a lot of waste heat on the other side of the thermocouples. The article denotes the possibility of re-using waste heat for heating or energy generation purposes. Finally, the article discusses the possibility of using power generated energy or waste heat in order to generate the electrical energy needed fort he thermocouples.

    A cooling coaster that holds and maintains cooler temperatures on various beverages. The coaster includes; a cup bottom and cylindrical sidewall and a sealing ring gasket integrally formed with the cylindrical sidewall. Normally, coasters operate by receiving and/or trapping condensation (Condensation forms on the exterior of the container) and preventing moisture from reaching the tabletop. Moreover, holders that maintain beverages cold include insulated cups, having thermally insulated walls. These holders maintain the beverage’s temperature (cold or hot, depending on the beverage and application) by preventing heat loss (insulation) on the liquid. However, such beverage coolers are of a height that covers up the label of the container. The device tackles the need of maintaining beverages cold, while not concealing the label of the beverage at hand, which can be also used as a coaster.  The invention provides a cooling coaster including a cup shaped body having a closed bottom and a cylindrical sidewall forming an opening at a top of the beverage. The device will also provide a supporting method that will hold the position of the beverage when placed on a tabletop or any other surface. The cooling coaster contains a shallow cup like body that has a place to place the beverage. The walls of the beverages are also well insulated, such that temperature loss is avoided.  All components are assembled into one piece such that handling and usage of the device is simplified. The coaster will also have a condensation control rim formed at the body to prevent liquid from reaching the tabletop.

[1] J. Skovajsa and M. Zálešák, “Thermoelectric cooling in combination with photovoltaics and thermal energy

storage” MATEC Web of Conferences, vol. 125, p. 02032, 2017.

[2] A. Mary, “Cooling Coaster for Beverage Containers” Patent: US 7712625 B2

4)

    The article and patent that intrigued my search regarded the use of thermoelectric generators. In particular, the journal article is about a solar thermoelectric generator while the patent is a generic thermoelectric generator capable of storing energy and converting it into a temperature difference. Solar power is incredibly interesting to our project as an anticipated application would be to utilize our product in large arenas and stadiums. Our product would be installed in a limited amount of luxury seating in order to increase appeal of those areas of the

venues. In order to power the coasters in an environmentally friendly facet a solar approach could be explored.  The journal article titled “Concentrated solar thermoelectric generators” conducts an in-depth analysis of solar thermoelectric generators, referred to as STEGs, and the optimization of materials to improve efficiency. STEGs offer an alternative to concentrated solar power and even operate at higher temperatures.  The ability to operate at higher temperatures as well as condense the entire energy collection process of our system is very enticing. Pushing the limits of a solar thermoelectric generator would not only raise the possible performance of our product but allow a venue to have more stadium coasters available to patrons. Also, the more compact our process can be the better our product will perform in the long run.

     The fact of the matter is that our products will need to be powered by some source of energy. If extra generators are going to be needed in order to power our equipment a solar powered energy source might as well be utilized.  The patent I selected is a simple thermoelectric generator. Within this particular thermoelectric generator semiconductor utilize the Peltier effect in order to generate an electrical current and in turn a temperature spike. They key in thermoelectric generators is the various efficiencies they operate on both the hot and cold sides. Utilizing a direct current is crucial in increasing the performance of your generator. Due to the Peltier effect, the configuration operates as a heat pump and cooler to the other side. An extremely important principle of a thermoelectric generator is contact pressure between the two materials. It is crucial to have an adequate amount of pressure in order to obtain abundant heat transfer in this process.

    When considering a physical model, it is important to consider cost, material efficiency, and contact pressure. These three characteristics are ideally going to determine the success of our model. As college students we have a limited budget however it is not very difficult to get cost-effective, quality thermoelectric material on Amazon and even eBay. Furthermore, the construction of our physical model is incredibly important as a maximum in contact pressure and surface area coverage will greatly affect the data collected in testing.  It will be interesting to see if solar could be utilized within our project. It is an intriguing alternative to traditional electricity and evidently grows the unique quality of our product.  However, if solar power cannot be utilized, a thermoelectric generator will still be very usable as well.

[1] Baranowski, Lauryn. “Concentrated solar thermoelectric generators” Energy Environ

Sci. Vol. #5. (2012) http://pubs.rsc.org.gate.lib.buffalo.edu/en/content/articlehtml/2012/ee/c2ee22248e

[2] Madalina Andreea, Stefan. Roland, Bauer. “Thermoelectric generator” TW201234687

(2012) https://worldwide.espacenet.com/publicationDetails/biblio?CC=TW&NR=201234687A&

KC=A&FT=D&ND=3&date=20120816&DB=EPODOC&locale=

5)

    This journal article provides a unique mathematical insight into the technology of Thermoelectric Cooling (TEC). Having a wide range of possible uses, this technology has become very prominent in the future of cooling devices.

    Still in its infancy however, TEC remains rather inefficient due to its elevated cost and low energy efficiency. The upsides, however, make this a technology worthy of continuing research. These advantages include high reliability and no moving parts. With regards to our project, the main advantages of TEC relate to it being very compact in size and the lack of requirement for a working fluid to transfer heat.

    A thermoelectric module consists of many thermocouples wired electrically in series and thermally in parallel. Semiconducting thermoelements within these thermocouples generate the Peltier-Seebeck effect with a voltage is applied through the material. This generates a hot and cold side within the module, whose effects can be amplified with the use of heat sinks attached to both sides. While many new thermoelectric materials have been in development over the past few decades, none are yet practical for large scale utilization, but their performance in smaller conditions make them of practical consideration for our design project.

    The author states many current applications for TEC exist in the civil market, including beverage can coolers. He also goes on to include that thermoelectric refrigeration devices are more ecological, quieter and have more precise control over temperature when compared to more conventional cooling systems. Many of the heat transfer equations and operational strategies presented in this journal will likely prove to be significant in the layout and design of our project. 

    Much of the information contained within the patent pertains directly to our intended design for our project and is related to the journal article previously mentioned. One of the first portions to stand out comes in sections 10-12 of the patent where it describes the heat radiating air ducts required to maintain temperature within the design. This is certainly of use to our project and was certainly an oversight in our initial design phase in MAE451.

    Sections 14-19 of this patent continue to describe the orientation of the Peltier model with respect to the cup holder and the air ducts present within this particular design. This is important to our design phase as the orientations presented here in this patent are vastly different from our initial design phase which will certainly require several adjustments.

    Despite this lack of knowledge in our initial design, we were not very far off from matching the overall operational ability of the system presented in this patent here. Many of the figures and descriptions can certainly be utilized to help further us in our design process. For example, the fan and heating duct as shown in figure 3 is quite similar to what we had envisioned with our initial product design, however I feel we vastly underestimated the amount of air that will need to be moved throughout the system for it to properly function. That being said, the information contained within this patent will certainly assist us in reaching our goal of a finished, working prototype.

[1] Zaho, Dongliang and Tan, Gang. “A review of thermoelectric cooling: Materials, modeling and applications.” Applied Thermal Engineering Vol. 66 Issue No. 1-2. pp. 15-24. DOI 10.1016/j.applthermaleng.2014.01.074. https://www-sciencedirect-com.gate.lib.buffalo.edu/science/article/pii/S1359431114000854?via%3Dihub.

[2] Oh, Man Ju. Kim, Jae Woong. Park, Jae Woo. 2016. “Cooling and heating cup holder.” US 2016/0137114A1.