Person:
Alegría Cía, Patricia

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Alegría Cía

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Patricia

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Ingeniería

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ISC. Institute of Smart Cities

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0000-0003-1174-2037

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811965

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Now showing 1 - 3 of 3
  • PublicationOpen Access
    Experimental development of a novel thermoelectric generator without moving parts to harness shallow hot dry rock fields
    (Elsevier, 2022) Alegría Cía, Patricia; Catalán Ros, Leyre; Araiz Vega, Miguel; Rodríguez García, Antonio; Astrain Ulibarrena, David; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería
    Nowadays, geothermal energy in shallow hot dry rock fields is not exploited enough due to the high economic and environmental impact as well as the lack of scalability of the existing technologies. Here, thermoelectricity has a great future potential due to its robustness, absence of moving parts and modularity. However, the efficiency of a thermoelectric generator depends highly on the heat exchangers. In this work, a novel geothermal thermoelectric generator is experimentally developed, characterizing different configurations of biphasic heat exchangers to obtain low thermal resistances that allow the maximum efficiency in the thermoelectric modules. As a result, robust and passive heat exchangers were obtained with thermal resistances of 0.07 K/W and 0.4 K/W in the hot and cold sides, respectively. The geothermal thermoelectric generator was built with the most effective heat exchangers and was experimented under different temperature and convection conditions, generating 36 W (17 W by a prototype with 10 modules and 19 W by a prototype with 6 modules) for a temperature difference of 160 °C between the heat source and the environment. Furthermore, the experimental development showed that it is possible to increase electricity generation with a more compact generator, since a decrease in the number of modules from 10 to 6 increases the efficiency from 3.72% to 4.06%. With this research, the feasibility of a novel and robust geothermal thermoelectric generator whose working principle is phase change has been experimentally demonstrated, as well as the importance of compactness to maximize its efficiency and thus, power generation.
  • PublicationOpen Access
    Experimental development of a novel thermoelectric generator without moving parts to harness shallow hot dry rock fields
    (2021) Alegría Cía, Patricia; Rodríguez García, Antonio; Catalán Ros, Leyre; Astrain Ulibarrena, David; Araiz Vega, Miguel; Ingeniería; Institute of Smart Cities - ISC; Ingeniaritza
    Nowadays, geothermal energy in shallow hot dry rocks is not exploited enough due to the high economic and environmental impact as well as the lack of scalability of the existing technologies. Here, thermoelectricity has a great future potential due to its robustness, absence of moving parts and modularity. With this research, the feasibility of a novel and robust geothermal thermoelectric generator whose working principle is phase change has been experimentally demonstrated, as well as the importance of compactness to maximize its efficiency and thus, power generation.
  • PublicationOpen Access
    Field test of a geothermal thermoelectric generator without moving parts on the Hot Dry Rock field of Timanfaya National Park
    (Elsevier, 2023) Catalán Ros, Leyre; Alegría Cía, Patricia; Araiz Vega, Miguel; Astrain Ulibarrena, David; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    Although in the last years thermoelectric generators have arisen as a solution to boost geothermal power generation, tests on field are still scarce. The vast majority of the available studies focus on computational simulations or laboratory experiments, mainly with active heat exchangers that require pumps or fans, and, consequently, present moving parts and auxiliary consumption. The present paper demonstrates for the first time the suitability of a geothermal thermoelectric generator (GTEG) with passive phase change heat exchangers, and therefore, without moving parts nor auxiliary consumption, on the shallow Hot Dry Rock (HDR) field of Timanfaya National Park (Canary Islands, Spain), where 173 °C air anomalies can be found. The device has been in operation without maintenance for 2 years now, producing more than 520 kWh of energy. In terms of power generation, since the installed device is in turn composed of two prototypes with 10 and 6 thermoelectric modules, it has been confirmed that installing more modules leads to a lower generation per module, although total generation can be higher. In fact, the prototype with 10 thermoelectric modules generated a maximum of 20.9 W (2.09 W per module) with a temperature difference between sources of 158 °C, while the prototype with 6 thermoelectric modules obtained 16.67 W (2.78 W per module) under the same conditions. These results open the door for a large-scale exploitation thanks to the intrinsic advantages of modularity, reliability, robustness, and minimal environmental impact of the developed device.