Personal protective equipment and personal cooling garments to reduce heat-related stress and injuries

Use of appropriate personal protective equipment is essential for healthcare workers when dealing with patients who have tested positive or are suspected of having Covid-19. Personal protective equipment is uncomfortable at best. In hot countries (like India) or in a hot place of work, its wearers are at a high risk of heat-related illnesses. Once in personal protective equipment a healthcare worker can remain in it for at least 6 h at a stretch. In summer when it is hot and humid, personal protective equipment can cause wearer dehydration, heat exhaustion or heat fatigue. In a severe form, this can result in heat stroke and a collapse while on duty. Preventive measures are needed to protect healthcare workers. This review aims to highlight the efficacy and applicability of personal cooling garments.

A Statistical Study to Evaluate the Performance of Liquid Cooling Garments Considering Thermal Comfort

Liquid cooling garments (LCGs) are considered feasible cooling equipment to protect individuals from hyperthermia and heat-related illness when working in extremely hot and stressful environments. So far, the goals for the optimization design of LCGs are mostly from the perspective of enhancing its efficiency and working time. However, thermal comfort is the key factor that is often not considered. In fact, many situations may cause discomfort. For example, the inlet temperature of the liquid-cooling vest changes constantly resulting in the change of thermal states of the human body. So, it is very significative to develop a method to evaluate the performance of LCGs considering thermal comfort. In this paper, an uncomfortable time ratio was proposed to evaluate the performance of LCGs considering thermal comfort. A series of tests were conducted by a modified thermal manikin method to evaluate the thermal properties. According to the analyses, the duration working time was 82.77 min, while the uncomfortable time ratio was too large, up to 57.6%. It showed that the thermal comfort should be considered when optimizing the performance of LCGs. The influences of different parameters such as volume of ice, flowrate, inlet temperature on the performance of LCGs were investigated through orthogonal experimental design. The statistical analysis illustrated that the influence of the volume of ice on the uncomfortable time ratio is greater than that of flowrate and ambient temperature. It is concluded that this method is useful for the control and design of LCGs considering thermal comfort.

A Statistical Study to Evaluate the Performance of Liquid Cooling Garments Considering Thermal Comfort

Liquid cooling garments (LCGs) are considered a feasible cooling equipment to protect individuals from hyperthermia and heat-related illness when working in extremely hot and stressful environments. So far, the goals for optimization design of LCGs are mostly from the perspective of enhancing its efficiency and duration working time. However, thermal comfort is the key factor which is often not considered. In fact, there are many situations that may cause discomfort. For example, as the ice melts, the inlet temperature of the liquid cooling vest changes constantly resulting in the change of thermal states of the human body, which lead to discomfort of human. So, it is very significative to develop a method to evaluate the performance of LCGs considering thermal comfort. In this paper, an uncomfortable time ratio was proposed to evaluate the performance of LCGs considering thermal comfort. It defined the proportion of uncomfortable time including overcooling and overheating in the entire working time. Series of tests were conducted by a modified thermal manikin method to evaluate the thermal properties. According to the analyses, the duration working time was 82.77 min, while the uncomfortable time ratio was too large, up to 57.6 %. It showed that the requirement of comfort should be considered when optimizing the performance of LCGs. The influences of different parameters such as the volume of ice, flowrate, inlet temperature on the performance of LCGs were investigated through orthogonal experimental design. The statistical analysis illustrated that the influence of the volume of ice on the uncomfortable time ratio is greater than that of flowrate and ambient temperature. It is concluded that this method is useful for the control and design of LCGs considering thermal comfort.

Comparison of heat transfer coefficient for different fabrics by vapor-compression system

The selection of a suitable fabric layer is an important aspect in the development of a cooling garment. One of the essential ingredients in selecting fabric for cooling garments is high heat transfer coefficient. In this study five different type of knitting fabrics with similar woven pattern were selected. The fabrics were attached to a vapor-compression system which is one of the most important systems in cooling garments. Heat transfer coefficient was calculated for each fabric for three different refrigerator flow rates. The most efficient fabric for applying in cooling garments was determined from the point of heat transfer coefficient.

Modeling the performance of a PCM cooling vest considering its side effects

Purpose – The purpose of this paper is to identify and evaluate the potential cooling contribution provided by a phase change material cooling vest as part of the total heat exchange mechanism of the body and take in to account the negative side effects of wearing the cooling garments. Design/methodology/approach – In this study, the three-part system of body-garment-environment has been simulated through the finite element method and the problem of heat exchange between these three parts has been solved with the help of computer modeling. Findings – The results of this modeling showed that a large percentage of the cooling efficiency of cooling vest was neutralized by the negative effects of the vest that are weight, lack of breathability, and the effects on the thermal conductivity of the skin. Therefore, the net efficiency of the cooling vests resulted in a lower decrease in skin temperature compared to the state that the negative side effects were not included in the model. Originality/value – Cooling power obtained with the help of cooling garments have been studied in previous studies using either human tests or manikins. But, what has been addressed less in previous studies relates to the negative effects of such equipment on the comfort of body, along with their cooling effect. So it is the first time witch the effect of side effects of such equipments are studied. Also modeling the real performance of cooling garments have not been done yet.