Feasibility study of retrofitting VAV system to VAV-DOAS system for outdoor airflow requirement and distribution in multi-zone VAV system

In this paper, we will focus on the retrofit of the ventilation system setup on the premise of reserving the original VAV system. Therefore, a combination of the existing VAV system and the dedicated outdoor air system (VAV-DOAS) is discussed. Here, the VAV system handles the indoor temperature and humidity without outdoor air supply, while the DOAS handles the indoor air quality with full outdoor air supply. The feasibility and economic analysis of this combined system are discussed by comparing it with the conventional VAV system operated in the multiple spaces equation-based strategy (MSE-V). The experimental results indicate that the presented VAV-DOAS can save 16% and 21% of energy consumption under winter and summer conditions in Dalian, respectively. Furthermore, this paper presents an economic evaluation method that can effectively evaluate the economy of a VAV-DOAS system retrofitted from the VAV system with different air conditioning loads and outdoor airflow demands. The economic analysis result shows that the retrofit system is economically feasible while the system is designed to serve for more than 12 years.

Automated summary

This paper focuses on the retrofit of the ventilation system while reserving the original VAV system, discussing a combination of VAV system and dedicated outdoor air system (VAV-DOAS). Experimental results show that the presented VAV-DOAS can save energy consumption in winter and summer conditions in Dalian. Additionally, an economic evaluation method is proposed to assess the economy of retrofitting a VAV-DOAS system from the VAV system.