Investigation of a Novel Thermoelectric Cooler for Building/Infrastructure Application

Liu, Haowen

Abstract

With the enormous building/infrastructure construction in advanced and emerging economies, the energy demand and carbon emissions from building/infrasturcture continues to rise. Buildings/infrastructure construction sectors contributed to 30% of global energy consumption and 27% of total energy emissions. To align with the carbon net zero scenario, carbon footprint from building need to more than halve by 2030, which requiring significant efforts on adopting clean and efficient technologies applicable to all end-uses. For energy consumption of modern building, heating, ventilation, and air-conditioning (HVAC) system play a critical role, which accounts for 40% of total building consumption and 70% of landlord consumption.
Thermoelectric coolers (TECs) are highly dependable, scalable, and noiseless devices. Beyond their conventional use, TECs have been investigated for a wide range of applications, including waste heat energy harvesting, electronics cooling, wearable device technology, power generation, and more. Numerous researches have unveiled their substantial potential in both domestic and industrial sectors, particularly in distributed building air conditioning. However, the cooling/energy performance of the TECs faces challenges in terms of building structures embedding, which limits its application. In particular, the integrated structure of TEC makes it difficult to dissipate heat to outside of building.
To overcome these challenges, the proposed research aims to investigate a novel TEC air cooler which has a number of distinguished innovations: (1) First-of-its-kind trial in separating hot and cold ends enabling placement of one side of TEC to outside of the building and another side of TEC to inside of building, thus creating an increased temperature gradient between the ends and increased cooling capacity. Furthermore, separated TEC makes it possible to be integrated with the building façade. (2) Initiative optimization of the TEC geometries enables the enhanced energy performance and cooling capacity that makes the TEC more building applicable; (3) Pioneering full-day case studies of TEC performance illustrates the applicability and adaptation of the coolers across different climatic conditions of the world.
This thesis employs a fundamental approach that integrates both theoretical and experimental analyses. The methodology comprises an exhaustive literature review, a conceptual design phase, mathematical analysis, model development, validation, and an in-depth examination of performance and thermal characteristics for thermoelectric geometry optimization. Furthermore, the thesis includes a conceptual design phase, mathematical analysis, model development, experimental testing, model validation, performance analysis, and real-climatic condition case studies.
Trials on the separated configuration TEC indicate that the specialist TEC, when applying 10 K temperature difference and 5A of current, led to reduction in cooling capacity by 5.6% compared to the integrated TEC, varying from 7.13 W to 6.76 W. However, the TEC device height will be doubled. While sacrificing a small portion of cooling capacity, the TEC’s application scenarios have been significantly broadened. It is noteworthy that separated-TEC configuration exhibits excellent cooling power density. The cooling capacity per unit area could exceed 15 kW/m2 under high current (I=5A), even at low current (I=0.5A), it is up to 500 W/m2.
Geometry optimization of the TEC reveals that the proposed design excels in both cooling performance and thermal-mechanical characteristics. The study demonstrates that under specified conditions, the truncated cone-shaped module (g) exhibits a noteworthy improvement in cooling capacity. In comparison to a traditional TEC, the cooling capacity from 0.1429 W increases to 0.1557 W, when operating at a temperature difference of 50 K, marking an 8.9% enhancement. This translates to a rise in the overall TEC device's cooling capacity from 18.15 W to 19.78 W. Additionally, the 'g' module, characterized by its absence of corners or edges, effectively reduces the peak von Mises stress.
A number of case studies were undertaken. The results show that, by introducing the separated-configuration structure, the unit cooling capacity of TEC system increases from 16.66 W/m2 to 18.82 W/m2 by 13%, while the cooling surface temperature is reduced by 0.2 °C.
This research shows that the TEC geometry optimization and separated TEC configuration create an opportunity to allow the TEC to be well integrated into a building. The cooling performance of the TEC could be improved by establishing the optimal geometry and its proper connection and configuration.

Citation

Liu, H. Investigation of a Novel Thermoelectric Cooler for Building/Infrastructure Application. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4571246

• Thesis Type: Thesis
• Deposit Date: Mar 4, 2024
• Publicly Available Date: Mar 7, 2024
• Public URL: https://hull-repository.worktribe.com/output/4571246
• Additional Information: Energy & Environment Institute; University of Hull
• Award Date: Feb 27, 2024