solar chimney

Over the last few decades, there is a clear target for reducing energy needs in the building sector. The above objective can be achieved both by renovating the existing building stock and/or by constructing new buildings that will meet the characteristics of zero or nearly zero energy buildings. In order to construct or renovate a building into a zero or almost zero energy building, different passive, active and hybrid systems can be used. One such system is a solar air heater collector.

Because of the need of energy conservation and Business Continuity Planning (BCP), natural ventilation system, which basically does not use non-renewable energy, is attracting academic/practical attention. However, it is difficult to predict the natural ventilation performance even after completion of the building, because it is easily affected by unstable conditions, such as outdoor temperature and wind. The designing and controlling method of natural ventilation system is not yet sufficiently established.

This work presents the thermal behavior of a stand-alone experimental solar chimney during one year. The dimensions of the solar chimney are 5.60 m high, 1.0 m width, and 0.52 m depth. The absorber plate is made of a common reinforced concrete wall of 4.5 m high, 1.0 m width and 0.15 m depth. This system was designed and constructed in 2003, and it is located in the “Laboratorio de Ensayos Energéticos para Componentes de la Edificación (LECE)” at the “Plataforma Solar de Almería (PSA)” in Spain.

The performance of a passive heating system was evaluated as part of design works for the project of an office building. The passive heating system incorporates an array of buried pipes together with a solar chimney. The solar chimney collects solar energy, heating fresh air and pulling it from an array of buried pipes. The array of buried pipes was used as an open loop earth-to-air heat exchanger and air circulation inside pipes is due to the action of the solar chimney. We studied the heating fractions due to the solar chimney and to the buried pipes.

In Mediterranean regions, characterized by a hot and humid climate during summer, the exposure of facades and the position of opening windows are important parameters to enhance passive cooling in the building using buoyancy-driven airflow. An example is the double skin façade which is directly exposed to solar radiation.

Solar chimneys may provide enough ventilation to buildings when properly designed. Although many design tools, theoretical models and experimental studies have been reported, the impact of many design parameters such as the construction thickness, the thermal resistance of the walls, the absorptivity of the internal surfaces of the chimney, the thermal mass of the chimney and the type of glazing, is not well known. This paper aims to provide information on the optimum sizing of the above parameters.

Natural ventilation driven by a solar chimney attached to a single-room building is investigated experimentally with a small-scale model using a recently developed fine bubble technique. Parameters studied in the experiments are the cavity width of the solar chimney, the solar radiation intensity, the height of the solar chimney, the room inlet area and the solar chimney inlet area. Results showed that for given building geometry and inlet areas, there is an optimum cavity width at which a maximum ventilation flow rate can be achieved.

The results of numerical simulation on the effects of solar chimney and underground cooling system for ventilation and heating in the new building of Faculty of International Environmental Engineering Kitakyushu University, Japan are described. It was found interesting to see the air flow rates with and without the effects of wind during the cooling period and air temperature during the heating period due to the solar chimney.