Experimental study on the thermal performance of composite phase change ventilated roof

Abstract

With the improvement of people's living standards, building energy consumption presents a trend of the increasing year by year. The phase-change energy storage technology is applied in the building so that the building envelope has good thermal insulation ability, and thermal storage performance the energy consumption of the building heating and air conditioning system will be greatly reduced. A new ventilated roof composed with multiple phase change material (VR-MPCM) was proposed as the experimental room, and a room of the same size conventional ventilated roof (CVR) was set as the contrast room. The PCM panel of myristic acid and tetradecanol was installed outside the test room, and the PCM panel of lauric acid and tetradecanol was installed inside. Then three kinds of summer experiments were carried out: stage Ⅰ, natural cold storage; stage Ⅱ, the ventilation layer regularly opened cold storage; stage Ⅲ, the ventilation layer regularly turned on and composite cooling. The research results show that compared with the comprehensive outdoor air temperature, stage Ⅱ can reduce the peak temperature in the experimental room by 41.1-44.9%, the minimum indoor air temperature increased by 19.2-27.7%; stage Ⅲ can reduce the peak temperature in the experimental room by 43.2-47.0%, and increase the minimum indoor air temperature by 26.7-43.9%. At the same time, stage Ⅱ reduces the dissatisfaction rate of the indoor thermal environment (DR) by 15.5% and stage Ⅲ by 40.2%. Regional comparison indicated that both stage Ⅱ and stage Ⅲ can effectively reduce the outer surface of the roof and indoor air temperature in severe cold areas, and reduce the fluctuation range of indoor air temperature, which has obvious potential for energy saving. Among them, stage Ⅲ will make the indoor environment more comfortable.