ABSTRACT
Thermoelectric modules can find practical application in clothing with a cooling function. A personal cooling system using Peltier modules integrated with clothing was developed and tested with the participation of a person. A dedicated electronic controller was designed that enabled the power or temperature to be controlled and recorded. In the research, the influence of heat sinks and the method of controlling the operation of the module on the cooling efficiency was assessed. The research was aimed at selecting the operating mode of the controller and choosing the arrangement of modules comparing cooling efficiency. The research showed that by selection of appropriate controlling mode, the electric power used can be reduced while keeping the cooling efficiency at the same level. The location of Peltier modules in places where they can tightly adhere to the body increases their performance.
ABSTRACT
The article presents a methodology developed for the evaluation of biomechanical energy harvesting systems that permits avoiding long-duration outdoor tests while providing realistic input signals and preserving uniform conditions across repeated tests. It consists of two stages: transducer output signal recording and power conversion and storage system measurements. The proposed approach was applied to assess the usefulness of a commercial electromagnetic transducer for supplying a Global Positioning System (GPS) receiver used as an active component of a smart clothing dedicated for mountain rescuers. Electrical power yield measurements have been presented together with ergonomic tests results. They all involved diverse physical activities performed by mountain rescuers that simulated their true operations, but were conducted in a training room for the sake of standardization. By providing reliable data on the transducer's performance under realistic use conditions, the proposed evaluation procedure revealed that the true energy yield was much smaller not only with respect to the manufacturer's assertions, but also substantially lower than what was expected based on an independent review which used unrealistic and non-uniform excitations. On the other hand, ergonomics ratings given by potential end users were very high, which demonstrates that the evaluated transducer can still be useful for supplying active cloth components with a lower power demand. The study also revealed that transducer location and orientation strongly affect its performance, which must be taken into account at the first stage of the evaluation procedure. Moreover, physical activity type and conditions (such as motion speed and ground tilt) influence the output power and should be carefully considered when composing a typical case scenario for the second stage.
