IELTS Reading Table Completion

Public buildings in warm regions are increasingly being designed to reduce the need for mechanical air conditioning. Architects call these methods passive cooling because they lower indoor temperatures without relying mainly on powered machines. The approach is not new: older houses in many climates used courtyards, thick walls and shaded openings long before electric cooling became common. One method is cross-ventilation. When windows or vents are placed on opposite sides of a room, moving air can carry heat away from occupants and surfaces. This works best when designers study the direction of prevailing winds before deciding where openings should go. If the openings face the wrong direction, the room may still feel still and humid. Another method is thermal mass. Materials such as stone, concrete and brick can absorb heat during the day and release it slowly at night. In schools and libraries, this can make indoor temperatures more stable, especially where nights are cooler than afternoons. However, thermal mass is less useful if the building cannot release stored heat after sunset. Shading is also important. Deep roof edges, external screens and trees can block direct sunlight before it reaches windows. External shade is usually more effective than curtains because it stops heat before it enters the glass. The best shading design depends on the sun's angle, which changes with season and time of day. Passive cooling is not a complete replacement for all mechanical systems. Hospitals, laboratories and data rooms may still need precise temperature control. But in many public buildings, passive methods can reduce energy demand and make indoor spaces more comfortable during ordinary use.