Exergy and carbon dioxide emission analysis for energy bus systems

Develops a general exergy and carbon dioxide emission analysis model for the natural water energy bus system (EBS), cooling tower EBS and single building cooling system. Taking a commercial building in Shanghai as an example, dynamically analyses hourly exergy and carbon dioxide emission of the three systems by means of TRNSYS software. The result shows that the descending order according to the exergy loss per unit refrigeration output is the single building cooling system, cooling tower EBS and natural water EBS with the respective value of 0.304, 0.266 and 0.185. In accordance with carbon dioxide emission per unit refrigeration output, the single building cooling system is the largest, the cooling tower EBS the second and the natural water EBS the smallest, with the value being 0.254, 0.215 and 0.189 kg/(kW·h) respectively. Compared with single building cooling system, the two EBSs have obvious superiority in exergy efficiency and carbon dioxide emission.