In many smart textile development studies, sensors and electro-conductive yarns have been widely investigated and used as essential components, especially in the fields of medicine, sport, work wear, and special applications. Wearable sensors provide a means to monitor the wearer’s health through physiological measurements in a natural setting or are used to detect potential hazards and alert users and/or caretakers. The aim of the research is to develop a prototype of wearable electronics that consists of high-performance clothing with an integrated energy harvesting system for converting the mechanical energy of human movements into electrical energy. Within the framework of the research, a system for determining human physiological and/or environmental parameters and transmitting data was developed and integrated into clothing modified with sol–gel technology for indoor and outdoor use. Although the created flat inductive elements of the energy harvesting system retain their performance during the hydrothermal treatment process, at the same time, the other elements of the smart clothing system (especially electro-conductive yarns) rapidly lose their electrical conductivity. The modified knitwear provided a longer time between washing cycles to protect the embedded wearable electronics, and the impact of surface modification with sol–gel on wearing comfort was evaluated.

An energy-independent wearable electronic system is being researched, where the energy required for its operation is obtained from human body movements and heat flow. The system power source consists of an electromagnetic motion energy harvester (mass up to 70 g, peak power reaching 38 mW depending on the intensity of movement), a thermoelectric harvester (mass 112 g, peak power up to 3 mW), power converters and a storage capacitor. The functional part of the system consists of a temperature and humidity sensors and a wireless data transmission module, while the energy-aware power management and the main function control is accomplished by a microcontroller, maintaining a safe input voltage range by adjusting the average consumption of the device. Only off-the-shelf components that provide greater configurability and could utilize a broader harvested voltage range were used. This study demonstrates that using a common energy storage element provides an energy flow stabilization effect that reduces the overall power instability, which can be a limiting factor for a single energy harvester system. The prototype was tested in controlled environment by walking on a treadmill and provided the necessary amount of energy for a sustained system operation even during motion pauses. Electrical energy storage efficiency of the system averaged at 17 %, with a peak efficiency reaching 21 %.

A combined human motion and heat energy harvesting system are under investigation. Main parts of the developed human motion energy harvester are flat, spiral-shaped inductors. Voltage pulses in such flat inductors can be induced during the motion of a permanent magnet along its surface. Due to the flat structure, inductors can be completely integrated into the parts of the clothes, and it is not necessary to allocate extra place for movement of the magnet as in usual electromagnetic harvesters. Prototypes of the clothing with integrated proposed electromagnetic human motion energy harvester are created and tested. Voltage of generated impulses is shown to be high enough to be effectively rectified with commercially available diodes and ready to be stored; however, efficiency depends on properties of controlling circuit. In order to increase the sustainability of the energy source and its stability, an option for combining a motion energy harvester with a human body heat energy harvester is also considered. Thermoelectric generator that harvests electricity from waste heat of human body is presented, and generated voltage and power are compared at different activity levels and ambient temperatures. Power generated with thermoelectric generator located on lower leg reached up to 35 mW with peak voltages reaching 2 V at certain conditions. A possible power management set-up and its efficiency are discussed.

Thermoelectric cooling is a prospective technology that has a lot of advantages; however, its main drawback is its low efficiency compared to other technologies. A lot of scientific research is aimed at the improvement of the efficiency of thermoelectric cooling, including the development of new thermoelectric materials, innovative structures, and better power management strategies. The present work further explores a self-developed recuperative power management approach, which takes advantage of the thermoelectric element’s ability to work as an electrical generator. This study relied on the thermal–electrical analogy method to develop a model that is capable of describing the impact of recuperation on the cooling performance while preserving the simplest configuration possible. The influence of different variables was estimated by three suggested quantities for evaluating the gains, losses, and rationality of the recuperative approach. A recovery of up to 10% of the electrical energy supplied to the thermoelectric element was observed experimentally. The ratio between the recovered energy and induced heat losses did not exceed a factor of 0.9. It is concluded that the recuperation process is reasonable only in the case of unavoidable interruption of the cooling process when average-performance thermoelectric elements are used.