COMPOSITE DESIGN AND THERMAL COMFORT EVALUATION OF SAFETY HELMET WITH PHASE CHANGE MATERIALS COOLING

Higher temperature and humidity will adversely affect the thermal comfort of helmet users. In order to improve the comfort level of the helmet and obtain an optimal cooling helmet model, four kinds of helmet models were established by using phase change material, heat-absorbing cooling technology, and fan cooling technology. Through the air conditioning system, the working states of four kinds of helmet models in the thermal environment of 30 degrees C were simulated, and the thermal comfort of four kinds of helmet models was evaluated. The results show that: high temperature environment is an important factor affecting the cooling effect of fan helmet fan, Under high temperature environment, the helmet with fan cooling technology has a certain cooling effect in the early stage, but after 30 minutes, the cooling effect becomes worse and worse. Under high temperature environment, phase change materials safety helmet has a good cooling effect, but poor ventilation results in the excreted sweat clinging to the scalp and hair resulting in a poor user experience. There are defects in using phase change material heat absorption cooling technology or fan cooling technology alone. The helmet combines phase change material heat absorption cooling technology with fan cooling technology so that the cooling effect and internal thermal environment stability of the helmet are the best, and the thermal sensation of human body is the best. Therefore, the helmet is an optimal design model.