The results presented in the figure 3 support the idea that if we consider that all building design variables (orientation, materials, SOF, TOF, technology, etc) are maintained constant and only the location of buildings in the city are modify; the emissions related to the energy consumption vary

significantly too. It is especially during winter’s month. During winter the heat island effect results in minor energy consumption and, in consequence decreases the emissions generation. This could be thought as a beneficial effect, but it is important remember, that associated with this phenomena there are other environmental problems, as it was explained in the introduction.

4. Conclusions

Until now, in the study area, the values of HDD and CDD calculated for the bioclimatic zoning not have been taking into account the effect of the city’s configuration over the local climate. The results of this study show that, take into account the microclimatic effect produced by the city’s configuration is of particular importance, because within this area it is concentrated the greater building and demographic growth; and it represent the 70% of power demand of the province.

It is observed that the magnitude of the error committed when misestimating the effect of the city on the energy consumption, represents one underestimation of roughly a mean 9% of cooling requirements reaching values of 43% in december, while in the case of the heating period the values calculated exceed in as much a 50% of the real downtown’s demand. Almost, this demonstrates the importance of the urban morphology not only in the energy behavior of buildings but also in their environmental impact. At the same time, the problem is that a new building will modify the environment where it will be inserted; generating microclimate modifications. These modifications will affect at the same time the immediate environment of the building, and the whole microclimatic behavior of the city.

At this point the question is to know how the city’s growth must be planned in order to minimize the environmental impact. On the study area especially, since the 90’s, a disperse growth of the urban population towards peripheral areas is observed, resulting in a population growth of 2.2 % in the central area, while in the peripheral districts this value fluctuates between 26.16 and 40.09 %[6]. The changing value of the soil’s use is the result of the lack of governmental policies to preserve the balance of the activity systems and the oasis environment and the real-estate speculation, which is constantly motivated by the constant urban population growth, and consequently stimulating the tendency towards spatial urban expansion. The rapid increase in population in the last decade combined with the changing consumption patterns and life styles, are resulting in land and climate degradation of this arid environment. Therefore, quantifying the

microclimatic effects of urban design decisions implemented in a city is information of key importance to assess its energetic and environmental sustainability.

Figure 3. Kg of CO2 emitted by each additional MJ consumed for heating and cooling urban and rural areas

because the heat island effect.

References

[1] Sailor, D. J., Munoz, J. R. (1997) Sensitivity of electricity and natural gas consumption to climate in the USA — Methodology and results for eight states. Energy 22, 987-998.

[2] Correa, E. N (2006). Tesis Doctoral. Isla de Calor Urbana. El Caso del Area Metropolitana de Mendoza. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Argentina.

[3] Akbari H., Davis S., Dorsano S. Huang J. And Winert S. (1992). “Cooling our Communities”. US Environmental Protection Agency, Office of Policy Analysis, Climate Change Division.

[4] Oke, T. R (2004). “Initial Guidance To Obtain Representative Meteorological Observations At Urban Sites”. Iom Report, Td In Press, World Meteorological Organization, Geneva.

[5] Erbs, D. G., Klein S. A. and Bechman W. A. (1983). “Estimation of degree days and ambient temperature data from monthly average temperatures”. ASHARE journal, 25 (6): 60-65.

[6] Alvarez, A (2000). “La Redefinition Territorial del Area Metropolitana de Mendoza en el Contexto de los actuates procesos de transformation”. Revista GeoNotas. Vol 4. N°4. Departamento de Geografia — Universidade Estadual de Maringa.