Abstract:Environmental conditions, such as air temperature and solar radiation, have a complex relationship with the energy requirements for heating and cooling of residential buildings. In this work, a comparative analysis of the insulation methods most commonly applied to low income single-family houses in Mexico is presented, in order to find the most energy-efficient combinations of methods for the various climates in this country. A common kind of building, small houses built with hollow cinder block walls and concrete slab roofs, was analyzed considering three insulation scenarios: walls only, roof only and both. We used dynamic simulation to evaluate energy consumption under the climate conditions found in several Mexican cities. From the energy consumption data and the cost of electricity in Mexico, we calculated net annual energy costs, including both annual energy savings and the annualized cost of the initial investment in better insulation. Results of this analysis show that insulating both roof and walls is most effective in cities with cold winters; insulating just the roof is best for temperate climates; and insulating walls (combined with high-albedo roofs) is most effective for cities with year-long warm weather.

Thermal building simulations were carried out for the climate conditions of 20 cities in México. We analyse the effects on energy consumption of variations in solar reflectance (SR), infrared emissivity (IE), and thermal insulation (TI) of a roof’s exterior surface. We quantify the maximum potential reduction in air conditioning annual electricity consumption and the most appropriate combination of optical properties to achieve this in every locality. We systematically varied the SR, IE, and TI of the exposed rooftop of a reference building. TI has the greatest energy-saving benefits when the optical properties of the roof are inadequate. The largest effects of SR and IE on energy consumption occur in countries with temperate climate dominated by energy requirements for cooling. In México, these cities are located in thermal zones 1 and 2, and it is within these zones that cool roof standards are recommended.

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