## 3 Methodology
During the HVAC off time, the ventilation setting is increased to simulate the effect of opening windows. The ventilation has an upper limit on the outdoor temperature of 32 \({}^{\circ}\)C and a lower limit on indoor temperature of 18 \({}^{\circ}\)C, simulating people closing their windows in hot or cold weather. The infiltration rate was set at 2 ach for the whole run period. The infiltration value initially referred to other researchers' studies and the Building Energy Code, and was fine-tuned in the validation run [36; 51]. EnergyPlus allows the simulation of the selected passive cooling techniques by adding geometry, changing materials or altering parameter setting. The reference value is based on the common practice in Hong Kong and original construction. The recommended value and test range of passive cooling techniques are based on the findings in the literature review. The material properties for the insulation and glazing are directly extracted from the built-in libraries of EnergyPlus, which are based on the American Society of Heating, Refrigerating and Air-Condition Engineering (ASHRAE) handbooks. SavE OM29 has a melting point of 29 \({}^{\circ}\)C and may be more suitable for use in Hong Kong. The data regarding its properties are extracted from the manufacturers' specification of the selected PCM [50]. The inputs for passive cooling techniques are shown in Table 4.  
In total, 22 sets of simulations were conducted to compare the annual energy performance and reveal the continuous performance characteristics of the techniques. For each set, at least one verification run was conducted, in which the EnergyPlus inputs, warning messages, simulated model, and the hourly result data were checked to ensure that the simulation is reasonable and matches real-world characteristics and other researchers' findings. The simulation timestep was set to three minutes. The weather data for Hong Kong was taken from the EnergyPlus website. It was developed from typical annual weather data by Dr [PERSON] and [PERSON] of the City University of Hong Kong. The solar radiation was measured at 22.32 N, 114.17 E, 65 m above mean sea level. The data are originally presented in a spreadsheet in International Weather for Energy Calculations (IWEC) format [52]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Categories** & **Variable** & **Baseline Value** & **Test Value** & **Rationale** \\ \hline Geometry & Building Orientation & 0\({}^{\circ}\) & 30\({}^{\circ}\), 45\({}^{\circ}\), 60\({}^{\circ}\) & \begin{tabular}{c} Change building axis angle for \\ different self-shading effect \\ \end{tabular} \\ \hline  & PCM & - & \begin{tabular}{c} SavE OM29 \\ (melt at 29 \({}^{\circ}\)C) \\ \end{tabular} & \begin{tabular}{c} Apply PCM to the innermost layer \\ of the exterior wall \\ Add insulation with different \\ thickness at the innermost layer of \\ exterior wall \\ \end{tabular} \\ Envelope & & - & \begin{tabular}{c} LoE 6 mm, \\ LoE Spec Sel 6 mm \\ \end{tabular} & \begin{tabular}{c} Change to high-performance \\ glazing, LoE Spec Sel is with even \\ higher performance \\ \end{tabular} \\  & \begin{tabular}{c} Window-to-wall \\ ratio (WWR) \\ \end{tabular} & 17.9\% & 14.3\% & \begin{tabular}{c} Reduce the window size by half for \\ conditioned zones to reduce WWR \\ \end{tabular} \\ \hline Solar Shading & \begin{tabular}{c} OPF (Fixed overhang) \\ SPF (Fixed side fin) \\ \end{tabular} & 0.3 & 0.5, 1.0 & \begin{tabular}{c} Increase the length of the overhang \\ over windows to reduce solar gain \\ Add side fin on both sides of \\ windows to reduce solar gain \\ \end{tabular} \\ \hline Ventilation & \
\begin{tabular}{c} Infiltration \\ \end{tabular} & 2.0 ach & 0.3 ach, 0.6 ach &
\begin{tabular}{c} Reduce the modelled infiltration \\ rate to the test value \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Passive cooling techniques simulation inputs in EnergyPlus v8.8.0.