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.

This study is focused to airflow and heat transfer analyses in an air-cooled room. Three-dimensional numerical results of a rectangular room considering three different inlet configurations are presented. The study was carried out considering turbulent flow and the radiative exchange between the walls. A vertical wall receives a constant heat flux, and the opposite wall is maintained at a uniform and constant temperature; the remaining walls are adiabatic. The air inlet velocity was 0.5 m/s and the emissivity of the walls was considered as 0.8. The mathematical model was solved numerically with Computational Fluid Dynamics software. The temperature fields, flow patterns, heat transfer coefficients, and temperature distribution effectiveness are presented and discussed. It was found that the heat transfer due to the radiative effect is around 50% for the three cases studied; besides, the heat transfer coefficients and temperature distribution effectiveness are highly dependent on the inlet position.

The thermal performance of economical housing located in hot climates remains a pending subject, especially in emerging economies. A cellular concrete mixture was designed, considering its thermophysical properties, to apply the new material into building envelopes. The proposed materials have low density and thermal conductivity to be used as a nonstructural lightweight construction element. From the design stage, a series of wall systems based on cellular concrete was proposed. Whereas in the second phase, the materials were analyzed to obtain the potential energy savings using dynamic simulations. It is foreseen that the energy consumption in buildings located in these climates will continue to increase critically due to the temperature increase associated with climate change. The temperatures predicted mean vote (PMV), electric energy consumption, and CO₂ emissions were calculated for three IPCC scenarios. These results will help to identify the impact of climate change on the energy use of the houses built under these weather conditions. The results show that if the conventional concrete blocks continue to be used, the air conditioning energy requirements will increase to 49% for 2030 and 61% by 2050. The proposed cellular concrete could reduce energy consumption between 15% and 28%, and these saving rates would remain in the future. The results indicate that it is necessary to drive the adoption of lightweight materials, so the impact of energy use on climate change can be reduced.

The experimental and numerical results of the heat transfer and airflow by turbulent mixed convection in a ventilated cavity are presented. The experimental setup was built to use air as the heat transfer fluid. One vertical wall receives a uniform and constant heat flux, whereas the opposite wall is maintained at constant temperature. The remaining walls are thermally insulated. The experimental temperature profiles were obtained for different heat fluxes and air inlet velocities. Five different turbulence models were used to obtain the numerical results. The comparison between experimental and numerical temperatures indicates that the standard k–ε turbulence model presents a better agreement, with maximum percentage differences between 2.0% and 3.0%. The heat transfer coefficient had values between 2.2 and 3.4 W/m² K, and it increases with the Rayleigh number and the Reynolds number. The experimental and numerical convective heat transfer coefficient predictions are closer for the higher Reynolds number (inlet air velocity of 0.5 m/s). The effects of varying the Rayleigh and Reynolds number on flow patterns and temperature fields were analyzed numerically.

The building sector is considered a key area for sustainable development, due to the potential to reduce greenhouse gas emissions in the numerous economic activities that this sector involves. A low-cost lightweight cementitious composite consisting in perlite mortar was fabricated and evaluated. The thermal conductivity and heat capacity of the proposed composite were tested in the laboratory. The lightweight composite was integrated into a prototypical house and its thermal performance was tested for two different arid climates during a typical meteorological year. A techno-economic analysis of this integration was carried out, which showed the lightweight system integration could reduce the energy demand up to 10.3% due to the decreased use of heating and cooling systems. The CO₂ emissions associated with electricity and gas use on cooling and heating systems could be reduced up to 10.9%.