**CAPITAL CITIES ELEVATION COMPARISON**

**Figure 2.** Comparison of Mexican capital cities elevations, and the relationship of elevation with cold and warm climates. The coldest climates are located on mountains and at high elevations, whereas the warmest climates are located at low elevations close to sea level.

> For constructing a building energy model (BEM) and a verification/certification model, a simplified and more practical climatic zoning is needed. A similar climatic zoning design procedure was followed by Bai and Wang for defining climatic zoning in China. They used building simulation to analyze the potential impact of re-assignment of cities to new thermal climate zones based on public building energy consumption and recent meteorological data..The defects of current climate zones were identified and new updated zones were defined [19]. For each climatic zone, several reference and nominal values were considered for their entry in the software calculations (average temperatures, average humidity, winter and summer severity, etc.) Therefore, we decided to design a new zoning based on thermal demands. For the proposed classification, several housing models that are common in the majority of Mexican cities were studied. Three models were selected: economic house, medium-level house, and apartment block. The three models were selected from the web-page catalogue of a real estate broker affiliated with INFONAVIT [20]. These models were chosen because of their constant replications in all the Mexican states. For the energy simulation, Open Studio software with the extension SGSAVE was used. SGSAVE is a complement developed by the Spanish energy testing software developer EFINOVATIC [21]. Since 2018, it has served as an official verification tool of the energy requirements of the Spanish building normative. Using the Energy Plus simulation engine (with local parameters and building geometry), the software conducts an energy simulation, providing an analytic report of different environmental results [22].

> Using this software, the project continued with simulations for each house model. The simulation output the energy demands for heating and cooling for each housing type (expressed in kWh/m2). The simulation period considered for the results was one year.

The Energy Plus Weather File (EPW) file or weather data file of capital cities [23] was used of each of the 32 states of the country, including the nation's capital city (Mexico City). Different simulations were performed by changing the position of the principal façade oriented to the four cardinal points (north, south, east, and west) for each house type. For a new simulation, we also considered the use of three different window-to-wall ratios: 10%, 30%, and 60% of openings (Figure 3).

**Figure 3.** Cooling and heating comparison for each of the housing model types, showing that medium-level housing registered the highest cooling demands in all climates. Economic houses registered the highest heating demands; however, scaling the results, the heating demands are lower (70 kWh/m2 for the highest value) than the cooling demands (125 kWh/m2 for the highest value).

Adding all the procedures, 384 simulations were conducted for both the heating and cooling demands for each house type. Once all the energy demand results were compiled, the four possible orientations were averaged for each capital city and each house type. The next step was averaging all the energy demands for all the capital cities, obtaining a mean value for heating demand and other for cooling demand. For the last step, an average value of all the energy demand for the three housing types was generated, obtaining final energy demand values for each capital city. The next step was attaining normalized values by scaling all cities' values for the collection of a unique scale of comparable values. We normalized the values by calculating an average value from all cities' values. This global mean value was assigned a numeric value of 1. So all cities' values were scaled in comparison with this numeric value. This procedure resulted in a scale ranging from 1 to 3 for three winter severities and a from V to Z for five summer severities. The final scale included a total of ten climatic zones, displayed on Figure 4 map.

The ten climatic zones were divided in three groups. The first group corresponds to cold and temperate climates, containing V1, V2, and V3 zones. The V zones contain the majority of the national territory, except for Estado de Mexico, which has the coldest climatic conditions in the country. This group has a temperature range of 0 to 21 ◦C 73% of the time [24]. The next group corresponds to warm and tropical climates, containing W1, W2, and X1 zones. The W and X zones are located in states next to the Pacific Ocean (Michoacán and Colima), and Yucatan Peninsula. This group presents a temperature range from 21 to 27 ◦C 40% of the time, and from 27 to 38 ◦C the other 40% of the time [24]. The last group corresponds to arid and desert climates, containing Y1, Y2, Z1, and Z2 zones. The Y zones are located in the northern coastal states (Baja California Sur, Baja California Norte, Sinaloa and Tamaulipas, and Sonora) and Nuevo León. This group presents a temperature range from 27 to 38 ◦C 50% of the time, and temperatures higher than 39 ◦C the 10–20% of the time [24].

**Figure 4.** Climatic zoning designed for the proposed verification method using winter and summer severities for analysis and comparison.
