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Urban parks are an important component of urban public green space and a public place where a large number of urban residents choose to conduct outdoor activities. An important factor attracting people to visit and stay in urban parks is its outdoor thermal comfort, which is also an important criterion for evaluating the liability of the urban environment. In this study, through field meteorological monitoring and a questionnaire survey, outdoor thermal comfort of different types of landscape space in urban parks in Chengdu, China was studied in winter and summer. Result indicated that (1) different types of landscape spaces have different thermal comforts, (2) air temperature is the most important factor affecting outdoor thermal comfort; (3) because the thermal sensation judgment of outdoor thermal comfort research in Chengdu area, an ASHRAE seven-sites scale can be used; (4) the neutral temperature ranges of Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) in Chengdu in winter and summer were obtained through research; (5) and UTCI is the best index for evaluating outdoor thermal comfort in Chengdu. These findings provide theoretical benchmarks and technical references for urban planners and landscape designers to optimize outdoor thermal comfort in urban areas to establish a more comfortable and healthy living environment for urban residents.

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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 (PCM) 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? 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 (b) 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, PCM safety helmet (c) 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 (PCM) heat absorption cooling technology or fan cooling technology alone. The helmet (d) combines PCM 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 (d) is an optimal design model.

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