This paper establishes models of the VRV & fresh air conditioning system and the primary return air conditioning system by using the software of Airpak, to simulate the temperature field and velocity field distribution of indoor air flow under two conditions in summer, and then to evaluate indoor thermal comfort and air quality by adopting the indexes like PMV-PPD and air age. Results show that both the wind speed of two schemes can meet the requirements of comfort air conditioning, without obvious sense of blowing for people. Compared with the VRV & fresh air conditioning system, the primary return air conditioning system has smaller air flow disturbance, smaller temperature fluctuation in respiratory area, and better indoor air quality with timely delivered fresh air.

For the domestic BIM engineering quantitystatistics, due to the insufficient localization of the BIM technology system, there are problems existed in the actual project includingpooraccuracy, insufficient timeliness and inadequateapplicability. In some projects, the BIM application and engineering quantitystatistics even act a dual-track system, which result in duplication of labor and waste of resources. Taking the demonstration project as an example, this paper analyzes the challenges and difficulties in the engineering quantitystatistics. The paper starts from the project application requirements, referencesinternational standards, and proposes an innovative technical route of BIM-based engineering quantitystatistics with a technical solution for localization of component coding and attribute information. The studies in this paper provides new ideas for the rapid generation of engineering quantity statistics based on BIM.