Digital-Twin-Based Evaluation of Nearly Zero-Energy Building for Existing Buildings Based on Scan-to-BIM

Table 2

Heat transfer coefficient of building envelope.

Number	Envelope element	U coefficient (W/m^2·K）	U coefficient (requirements for nZEBs [4, 40] (W/m^2·K）
1	East/west facade	0.5	0.2
2	South/north facade	1.9	1.2
3	Roof	0.42	0.2
4	Floor	1.39	0.4