Preliminary characterization of a dual-source passive building cooling system based on loop thermosyphon

Abstract

Passive cooling technique is an efficient way to avoid the high energy consumption of conventional air conditioner in heat dissipation of industrial buildings, in which loop thermosyphon has shown an attractive application prospect. But the normal loop thermosyphon cooler only relies on the air source heat exchange, and an obvious performance degradation will occur when the ambient temperature is high. In this paper, a new scheme combining sky radiative cooling and direct evaporative cooling for the passive condenser heat dissipation of loop thermosyphon is put forward. The characteristics of this dual-source passive building cooling system is simulative investigated. The effects of ambient temperature, ambient relative humidity, indoor air temperature, evaporator air velocity, and solar radiation intensity are discussed in detail to determine its thermal characteristics. The system exhibits a relatively stable heat exchange capacity of 398.3 ∼ 505.6 W at various outdoor boundary conditions and a preferable cooling performance under high ambient temperature in comparison with conventional air source loop thermosyphon cooler. The thermal analyses show that coupling of sky radiative cooling and direct evaporative cooling with a loop thermosyphon enables high cooling capability in normal working conditions to accomplish indoor thermal comfort. Results demonstrate effectiveness of the proposed system on achieving reliable, sustainable, and efficient passive cooling for industrial buildings.