Associate Professor, Università degli Studi di Trieste
Marco Manzan is Associate professor of Thermodynamics and Heat Transfer at the University of Trieste. He received his degree in Aeronautical Engineering at the Politecnico di Milano in 1989. Prof. Marco Manzan main research effort has been committed to the numerical analysis of heat transfer problems working on the following arguments: finite element method solution of thermal problems, conduction and convection coupling stability of numerical methods natural and forced convection problems.
The maintenance of healthy conditions in all seasons is a prerequisite for buildings in industrialized countries, however this is usually accomplished installing climatization plants which contribute in a steady manner to the constant increase of energy consumption and CO2 emissions. For this reason passive design systems are drawing great interest from researchers and designers since they can help reducing the loads and therefore the amount of energy required for maintaining predefined internal healthy conditions.
One key component for an energy conscious building is the façade since it separates the internal comfortable environment from the external ambient. Nowadays office buildings present extensive glazed areas in order to assure a good daylight distribution, but a drawback is that this design is responsible of high cooling loads, especially in Mediterranean area. In order to reduce this problem, Italian national codes require the compulsory installation of external shading devices or glazing systems with low solar gain coatings.
External shading devices can be fixed or moveable and each solution has its drawbacks and advantages, for example a fixed device has low maintenance cost, but can be optimized for a single season, on the other side a moveable device such as an external venetian blind, can be effective and also deployed to avoid glare problems but can became too obstructive for the view of the occupants towards the external environment. In this presentation an external fixed shading device is considered.
The geometry is optimized taking into account the overall energy consumption for building climatization and illumination. To avoid glare problems an internal venetian blind is considered too so the fixed shading devices influences the deployment of the moveable internal venetian blind. The external shading is optimized by taking into account the geometry such as length, height, and inclination angle, while two objectives to be minimized are considered, the overall primary energy consumption and the time of deployment of the internal venetian blinds. Two computers codes have been used: DAYSIM for computing daylight parameters and ESP-r for energy computation, while modeFRONTIER performs the synchronization between numerical codes while processing the optimization objectives.
For Daylight computation with shading devices two approaches have been followed, the former considers the geometry of the internal blind into the raytracing process performed by DAYSIM, while in the latter a simplified approach is used in which the effect of the internal blinds is recovered from the results of the unobstructed case. The full approach is time consuming and therefore an efficient FAST algorithm has been used in order to obtain the Pareto front, while for the simplified approach a genetic optimization has been also selected in order to compare different approaches. The results obtained show how the FAST algorithm is capable of identifying with accuracy the designs pertaining to the Pareto Front.