Abstract:

To evaluate the insulation performance of sleeping bags during actual use in various low-temperatures, wind speeds and wind directions, and to improve the comfort of sleeping bag users, an experimental study on the thermal insulation performance of sleeping bags was conducted. The thermal insulation performance of mummy-style sleeping bags and envelope-style sleeping bags was evaluated using a low-temperature coupled environment chamber and "Newton" thermal manikin system. Thermal resistance parameters of the two types of sleeping bags under varying environmental temperatures (-20, -15, -10, and -5 ℃), wind speeds (1, 2, 3, 5, and 7 m/s), and wind directions (along the head, waist, and foot directions) were measured. The effects of a single low-temperature windless environment and a combined low-temperature windy environment on the thermal insulation performance of sleeping bags were studied. The experimental results show that in a single low-temperature windless environment, the thermal resistance value of the mummy sleeping bag changed more stably than that of the envelope sleeping bag, and the mummy sleeping bag has better thermal insulation performance. In a combined low-temperature windy environment, increasing the wind speed would reduce the thermal resistance of the air layer; and when the wind speed was 7 m/s, the thermal resistance of the air layer decreased by 50%. Wind direction along the head direction has the greatest impact on thermal resistance, with the total thermal resistance of the mummy sleeping bag decreasing by 42.8% and that of the envelope sleeping bag decreasing by 50.1%. Wind direction along the foot direction had the least impact on the thermal resistance value of the sleeping bag, with the total thermal resistance of the mummy sleeping bag decreasing by 23.1% and that of the envelope sleeping bag decreasing by 29.3%.When the wind speed along the head was 7 m/s, the air layer temperature at the feet of the mummy sleeping bag and the envelope sleeping bag dropped to the lowest, which were 21.83 and 26.54 ℃, respectively.

Key words: low-temperature composite environment, sleeping bag, thermal insulation performance, thermal manikin, wind speed and direction