The Impact of an Extensive Usage of Controlled Natural Ventilation in the Residential Sector on Large-Scale Energy Systems

The energy situation in the world is becoming alarming. The demand of electricity continues to grow whereas the means of production remain limited. In addition, the electricity generation in the world is mostly based on fossil fuels such as coal, oil and natural gas. Only a small share of the total generation is based on renewable energy.

As it is well-known, the combustion of fossil fuels produces gases – named greenhouse gases –which enhance the climate change on Earth. Therefore, the use of low-carbon technologies such as renewable energy is necessary in order to counter these emissions to the atmosphere.

On the other hand, the efficiency of the end-use energy consumption is also fundamental to decrease the electricity production thus to lower the emission of greenhouse gases. Thereby, the building sector is a very important target because it consumes approximately one quarter of the total annual energy in the world. Of this energy consumption, one of the highest energy-consuming activities within the buildings is concerning cooling. Technologies such as mechanical ventilation and air-conditioning are very used to achieve a certain thermal comfort within the building when there are periods of overheating.

The present thesis deals with the use of a non-consuming technology named natural ventilation. With natural ventilation, under the right outdoor conditions, it is possible to decrease the use of mechanical ventilation or air-conditioning therefore achieving an end-use efficiency which can be reflected in the reduction of the electricity production.

The objective of the thesis is to show realistic benefits of utilizing natural ventilation at an extensive manner onto large-scale scenarios such as a national scenario by using a model of natural ventilation developed here. To do so, a building simulation program and an energy systems analysis model are used as tools.

The residential sectors of Denmark – temperate conditions – and Mexico – warm conditions – are used as case studies. In both scenarios, potential energy savings are assessed after using natural ventilation. Thereafter, environmental and economic benefits are estimated.

The environmental benefits are reflected into two main outputs. The first one is the greenhouse gases mitigation when fossil-fuel-based electricity generation is being held. The second one is the potential non-utilization of water reservoirs used to hydro power generation when a dry season occurs.

It is also found that controlled natural ventilation is a passive cooling technique suitable for an extensive use within the residential sector – among other cooling methods such as shading systems and building color – due to its wide scope of climate conditions, feasibility of implementation, high affordability and low maintenance requirements.

And although the results are dependent on the natural variations of the outdoor conditions, features such as the building design and the occupants’ behavior are indispensable to drive the best strategy of natural ventilation in every particular case of new or existing building in order to optimize the energy saving by avoiding consuming methods.