The Design of Building Envelope as a Tool For Achieving Environmental Design Goals

Abstract

This study discusses the building envelope from the environmental design point of view. The building envelope (or the building skin) is the external layer that wraps the building. It includes everything that separate the interior and the exterior of a building. It plays a great role in climatic control which has its direct effect on maintaining human comfort, and energy conservation. An energy-efficient building envelope decreases the need for energy consumed by appliances (like HVAC and lighting systems) through decreasing heat gains and accessing homogenous natural daylight and natural ventilation in addition to other functions. In addition to fulfilling these functions the envelope systems are integrated in the architectural design to serve for the building aesthetics.

The study discusses the title in three parts after a brief introduction that shows the environmental goals that the building envelope should help to achieve. Part I discusses "The Basics of Building Envelopes", Part II discusses the "Building Envelope Systems", and Part Ill discusses "Intelligent Building Envelopes".

t PARTI:" The Basics of Building Envelopes" This part discusses the basics that help understand the envelope systems that are discussed in Parts II and Ill.

The building envelope performs several functions, some are general and others are environmental functions. The envelope performs various general functions as it serves in the building aesthetics, controls physical access to the building and providing visual communications between the interior and the exterior. It also provides security, durability, and controls noise transmission. It can be act as a digital screen for multi• media uses.

The envelope performs environmental functions through climatic control (thermal control, natural ventilation and natural lighting), and energy conservation and production. Both environmental and general functions of the envelope are discussed in Chapter I Functions of Building Envelopes".

To control thermal transfer and natural ventilation through the envelope, it should first be clear how the natural phenomenon of heat transfer occurs. Heat transfers in three modes: conduction, convection and radiation. They usually act together in a combined mode. Each mode should be treated to control heat transfer. This is discussed in Chapter II "Principles of Heat Transfer".