Today’s state-of-the-art caloric technologies, such as magnetocalorics, electrocalorics or elastocalorics, are based on the so called Active Caloric Regeneration (ACR) principle. The ACR is based on the reciprocating movement of the fluid through a porous caloric structure. Such system usually comprises a large amount of caloric material and a fairly complex hydraulic system, which is more suitable to be implemented in large cooling, refrigeration or heat pump devices. On the other hand, miniaturized electronics also produce vast amounts of heat that need to be efficiently managed. In this manner, an alternative research approach is emerging in the fields of caloric technologies. It involves new concepts of devices, which would apply so called thermal switches. The application of thermal switches could lead to drastic improvements in the heat transport from/to the caloric material and consequently to the miniaturization of caloric devices. An interesting domain, to look for thermal switch mechanisms, is microfluidics, which has enabled the development of integrated lab-on-chip devices. Although most microfluidic devices are based on a continuous flow of liquids in microchanells, there has been an increasing interest for the past couple of years in devices that rely on manipulation of discrete droplets using surface tension effects. One such technique is ElectroWetting On Dielectric (EWOD), which is based on wettability of liquids on a dielectric solid surface by varying the electrical potential. In this contribution we will present a new concept of caloric device which couples caloric effect and EWOD droplet actuation as thermal switch mechanism. We will show different potential designs of such devices and their operation. Furthermore, the materials and its properties which constitute the whole device will be discussed.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 16800795The aerosol deposition (AD) is a relatively new method for rapid deposition of thick films of a variety of functional materials at room temperature. The complete consolidation of functional films happens in AD due to the impacting of high velocity particles with the substrate. The AD method offers an excellent way of integrating different materials together, such as ceramics, metals, polymers and glasses. For that reason, the AD method opens up new solutions when designing various applications, for example in preparation and integration of caloric elements for new solid-state cooling devices. In this contribution, we will present a few examples of integrating different materials by utilizing the AD method. We will demonstrate how the AD method enables preparation of alumina surface coatings for the protection and the electrical isolation of caloric elements. In addition, the possibilities and prospects of integrating caloric materials on a variety of low-cost substrates will be considered. Furthermore, the electric and electrocaloric properties of prepared aerosol-deposited layers will be discussed.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 16800539Caloric cooling, heat pumping and refrigeration are considered as some of the most important alternatives to existing vapor-compression technologies. In the past two decades we have seen a substantial increase in the number of basic and applied research efforts to bring this technology to the market. Despite the fact that researchers have made substantial progress, there are many open, unsolved and strongly inter-related problems regarding the use of caloric materials, energy efficiency and the competitive costs of such potential future devices. An alternative solution, that overcomes some obstacles in heat transfer and fluid dynamics, and leads to future research frontiers in caloric refrigeration, is associated with the application of thermal diodes or thermal switches. These kinds of solutions can lead to very high frequencies of operation (the number of caloric thermodinamic cycle per unit of time), that is, above 25 Hz, and substantially improved compactness. Increased research efforts in this particular domain have been underway in the caloric research community since 2010.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 16373787The subject of the research was a numerical investigation of the operation of a new method of operation of magnetocaloric refrigeration devices for which the patent "Heat transfer method in the united structure of recuperation unit and the recuperation unit construction" was granted (COBISS.SI-ID 14214659). The new method of heat transfer within the porous structures of the magnetocaloric material offers efficient operation at significantly higher operating frequencies than the current state of the art. The current state of the art (active magnetic regeneration) shows efficient operation up to 5 Hz, while our patented method allows efficient operation above 20 Hz. Efficient operation at higher operating frequencies leads to a higher power density and consequently enables the miniaturization of the cooling devices themselves.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 17041179