## 1 Introduction  
The problem of thermal load in the work environment due to the exposure to a hot microclimate still persists for a significant number of people and is expected to increase significantly with climate change [1]. Construction workers are one of the groups experiencing this problem due to their work outdoors, often in full sun. It is worth mentioning that 2022 was the warmest year on record for a large part of Europe [2]. According to the analysis conducted by [PERSON] et al. [3], as many as 61,672 deaths in Europe between 30 May and 4 September that year were related to heat. Therefore, it is recommended that construction companies provide additional solutions that will support workers' thermoregulation. From a technical point of view, preventing excessive thermal load while working outdoors is particularly problematic. In this case, in order to guarantee cooling effectiveness without negatively affecting ergonomics, the use of a personal cooling system seems to be the only possible solution. There are several cooling mechanisms that, when integrated with clothing, can significantly reduce a worker's thermal load. In particular, non-electric and electric cooling can be distinguished [4]. There are several methods currently available to provide personal cooling [5; 6]; however, considering the recent technological revolution that has led to Industry 4.0, including Construction 4.0 [7], particular attention should be paid to electronic solutions that enable their integration within Internet-of-Things architectures in the work environment (a construction site, in this case). A promising direction in this field is the application of thermoelectric modules (TEMs) whose operation is based on the Peltier effect [8]. The temperature difference created between the two sides of these TEMs can be used for either cooling or heating [9]. Since the cooling intensity of TEMs is adjusted through their electric supply power, their control by electronic devices is simple, direct, and efficient, without the need for any intermediate stages of energy conversion. The use of moving mechanical parts can be avoided, reducing the system weight and size and minimizing energy consumption, as well as increasing product reliability and service life. Supply voltages may be as small as just a few volts, making them safe for use in clothing and easily supplied from low-voltage energy storage devices, such as powerbanks. Recently, TEMs have been offered as flexible items, making their integration with clothing easy without compromising the ergonomic properties of the latter [10; 11; 12]. This feature is particularly important when TEMs are implemented into protective clothing as it makes it possible to avoid loose or protruding elements that could easily get caught, e.g., by operating tools or machines. In addition, TEMs are considered to be an environment-friendly alternative to other cooling technologies, which is an additional advantage considering the climate crisis [13]. In spite of the great potential of TEMs in personal cooling, there have been only a few solutions using this technology so far. Moreover, scientific reports related to the application of flexible TEMs mainly come from recent years, which additionally confirms the novelty of this research direction. One of the wearable thermoelectric devices for personal cooling was presented by [PERSON] et al. [12]. They proposed a vest and a band intended for use directly on the body. Using the developed devices, a temperature reduction of 5 \({}^{\circ}\)C was achieved, depending on the physical activity performed. A T-shirt with flexible TEMs and heat sinks containing phase-change materials was proposed by [PERSON] et al. [14]. The authors confirmed the cooling capability of the developed clothing in tests carried out in 23 \({}^{\circ}\)C and 32 \({}^{\circ}\)C using a thermal-imaging camera. The reduction in skin temperature underneath the TEM reached over 8 \({}^{\circ}\)C. Moreover, a reduction in skin temperature next to the TEM was also observed.