## 3 Case Study  
The case study for this research was a lecture room in the east Teaching Building of Dalian Minzu University. The goal was to validate the effectiveness and efficiency of the proposed BIM based building design method. The room had an area of 126.36 mq and was located at the northeast of the building on the second floor. The distance from the floor to roof was 4.5 m; the ceiling height was 3.5 m. There were 8 windows in the east wall, one narrow window in the north wall, and two doors in the south wall. The narrow window in the north wall was mainly aesthetic, and as such, was not considered during the design optimization process. Figure 2 shows the room's outline. There were a total of 20 lights in the room. Table 1 shows the detailed information about the initial design. To facilitate the application of the proposed design method, it was assumed that all the building materials were purchased in Liaoning Province. The building's lifetime was calculated as 50 years. The BIM software used in this study for the simulations was Ecotect Analysis 2011 (Autodesk Inc., San Rafael, Calif., the USA, 2011). The software established a 3D building information model, with the location and climate information. The workday schedule was set as 6:00 to 18:00. When calculating the total annual energy for the room, the year was set as 365 days, with no holidays during the year. In the lighting performance simulation module, the analysis grid was set at a height of 750 mm above the floor, with 496 uniformly distributed points. The standard illumination at the workplace was 500 lux; as such, the artificial light operation time was be calculated based on \(\overline{DA}\)500, and the lights were controlled manually. The city of Dalian in Liaoning Province of China, has a warm temperate continental monsoon climate. Therefore, both heating and cooling were required. In this case, a water-cooled chiller with \begin{table}
\begin{tabular}{c c} \hline \hline
**Design Factor** & **Variable Description** \\ \hline Window-to-wall ratio & 0.19 \\ \hline Glazing type & 6 mm double clear float glass with 6 mm air gap \\ \hline Wall type & 300 mm reinforced concrete wall + 50 mm EPS board \\  & +30 mm cement and sand (1:3) screed + 10 mm plaster \\ \hline Artificial light type & T8 fluorescent light, 30W \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Initial design of the case. Figure 2: Outline of the lecture room. a COP of 4.7 was used. The indoor design temperature was set at 26 \({}^{\circ}\)C in the summer and 18 \({}^{\circ}\)C in the winter, without night setback or setup. Additional study design details were as follows. Based on the charging standard of electricity in Dalian, the electricity tariff was set at 0.8 CNY/kWh. The real interest rate was counted to be \(-\)6.45%, based on the inflation rate. The maximum construction cost and the maximum LCC were set at CNY V50,000 and CNY V15,000,000, respectively, based on interviews with project owners and project managers. After a series of lighting performance and thermal performance simulations, simulation outputs were used to estimate the annual energy demand. This result was entered into the building design optimization system. Key parameters were set as follows: The cognitive parameter (c1) and social parameter (c2) were both set at 1.49445; the minimum inertia weight (wi) was 0.4; the maximum inertia weight (wa) was 0.9; the population size (N) was 50; the maximum iteration number (maxit) was 100; the maximum repository size (Anum) was 50; the grid inflation parameter (\(\alpha\)) was 0.01; the leader selection pressure parameter (\(\beta\)) was 10; and the grid sum per dimension (gridnum) was 50. Table 2 presents detailed information about the decision variables; these were also important design factors. Energy intensities of the materials were collected from [46] and determined based on [47; 48; 49; 50; 51]. After the iterations were completed, a Pareto frontier was generated (see Figure 3). Table 3 provides detailed information about the optimal designs.