International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 04 | Apr 2025
p-ISSN: 2395-0072
www.irjet.net
Review on Thermoelectric Energy powered wearables : A Sustainable Energy Approach A Comprehensive Analysis of Existing Technology, Design, Challenges, and Commercialization
Mr Aritra Banik1 1Student IInd Semester B-Tech (Electrical Engineering)
Dept. of Electrical Engineering, National Institute of Technology, Agartala , Tripura , India
---------------------------------------------------------------------***--------------------------------------------------------------------1.2 Body Heat: An Underutilized Resource Abstract - The rapid expansion of wearable IoT devices necessitates eco-friendly alternatives to conventional batteries. This study examines thermoelectric generators (TEGs) that harvest body heat via the Seebeck effect, leveraging advanced materials like Bi₂Te₃ nanocomposites and flexible organic thermoelectrics. Experimental results show that a 10 cm² flexible TEG yields 12–15 mWh/day under a 5°C thermal gradient, extending battery life by 30–50% when combined with hybrid solar-kinetic systems.
The human body dissipates 100–120 W of thermal energy daily, with skin surface flux ranging from 50–100 W/m² [3]. Thermoelectric generators (TEGs) leverage the Seebeck effect to convert this waste heat into electricity, offering a sustainable alternative to batteries. 1.3 Objective This project aims to analyze the efficiency of Thermoelectric Generators (TEGs) under thermal gradients of 1–10°C across various material configurations. It explores hybrid energy systems combining TEGs, solar cells, and piezoelectric harvesters, while also assessing market viability and identifying startup opportunities in sustainable, selfpowered IoT applications.
Key challenges include low power density (20–150 µW/cm²) and heat dissipation, mitigated through phase-change materials (PCMs) and AI-driven power optimization. Blackcoated TEG designs enhance heat absorption by 15–20%, while ergonomic forms ensure user comfort. The wearable IoT market, projected to reach $265.4 billion by 2030, presents significant opportunities, with 40% of devices likely adopting energy harvesting. Startups can target medical IoT (e.g., glucose monitors) and industrial safety (self-powered sensors) through modular designs and OEM partnerships.
2. Thermoelectric Energy Harvesting: Fundamentals 2.1 The Seebeck Effect The Seebeck voltage (V) generated across a TEG is proportional to the temperature gradient (ΔT): V=αΔT where: α = Seebeck coefficient (µV/K), material-dependent. ΔT = Temperature difference (K) between TEG’s hot and cold sides. CaseStudy:
This work bridges technical innovation with commercialization, offering a roadmap for sustainable, battery-free wearables. Future advancements in nano-TEGs and 6G integration could accelerate mainstream adoption, reducing e-waste and energy dependence. Key Words: IoT , TEGs , Seebeck effect , nanocomposites , thermoelectrics , PCMs , OEM 1. INTRODUCTION
A flexible TEG with α=220 μV/K and ΔT=5∘C generates: V=220×5 = 1.1 mv
1.1 The Evolution of Wearable IoT Wearable IoT devices have transitioned from niche fitness trackers to critical healthcare tools, enabling real-time monitoring of vital signs (ECG, SpO₂, glucose) and chronic disease management. By 2030, over 1.2 billion devices will be deployed globally, driven by aging populations and telehealth adoption [1]. However, reliance on lithium-ion batteries poses significant challenges: Limited Lifespan: Smartwatches require daily charging, disrupting continuous health monitoring. Environmental Impact: Only 5% of wearable batteries are recycled, contributing to 53.6 million tons of annual e- waste [2].
2.2 Power Output and Efficiency The maximum power (Pmax) generated by a TEG is governed by: Pmax=(αΔT)2/4R where R = Electrical resistance of the TEG. Example: For R=1.5 Ω , α=220 μV/K , α=220μV/K , and ΔT=5∘ : Pmax = (1.1 mV)2 / 4×1.5 Ω = 0.2μW Flexible Bi₂Te₃-PEDOT:PSS yields 80–100 µW/cm².
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