Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption. This approach works either by preventing heat from entering the interior (heat gain prevention) or by removing heat from the building (natural cooling).
26-923: Eastgate Mall , or Eastgate Shopping Centre , or similar, may refer to: Eastgate Centre, Harare , Zimbabwe Eastgate Consumer Mall , formerly Eastgate Shopping Center, Indianapolis, Indiana, U.S. Eastgate Mall (Chattanooga) , Tennessee, U.S. Eastgate Mall (Cincinnati) , Ohio, U.S. Eastgate Mall over I-805 Bridge , San Diego County, California, U.S. Eastgate Shopping Centre (Basildon) , Essex, England Eastgate Shopping Centre (Bondi Junction) , New South Wales, Australia Eastgate Shopping Centre, Gloucester , England Eastgate Shopping Centre (Inverness) , Scotland Eastgate Shopping Centre, Johannesburg , South Africa Eastgate Square , Hamilton, Ontario, Canada Sherwood Park Mall , formerly Eastgate Mall, Sherwood Park, Alberta, Canada See also [ edit ] Eastgate (disambiguation) Topics referred to by
52-454: A cooling strategy for buildings, including improved comfort and a shift in peak energy load. Energy is most expensive during the day. By implementing night flushing, the usage of mechanical ventilation is reduced during the day, leading to energy and money savings. There are also a number of limitations to using night flushing, such as usability, security, reduced indoor air quality, humidity, and poor room acoustics. For natural night flushing,
78-485: A natural cooling strategy uses the physical properties of air to remove heat or provide cooling to occupants. In select cases, ventilation can be used to cool the building structure, which subsequently may serve as a heat sink. These two strategies are part of the ventilative cooling strategies. One specific application of natural ventilation is night flushing. Night flushing (also known as night ventilation, night cooling, night purging, or nocturnal convective cooling)
104-475: A sink through the day and absorbs heat gains from occupants, equipment, solar radiation, and conduction through walls, roofs, and ceilings. At night, when the outside air is cooler, the envelope is opened, allowing cooler air to pass through the building so the stored heat can be dissipated by convection. This process reduces the temperature of the indoor air and of the building's thermal mass, allowing convective, conductive, and radiant cooling to take place during
130-435: Is a deliberate move away from the "big glass block". Glass office blocks are typically expensive to maintain at a comfortable temperature, needing substantial heating in the winter and cooling in the summer. They tend to recycle air, in an attempt to keep the expensively conditioned atmosphere inside, leading to high levels of air pollution in the building. Artificial air-conditioning systems are high-maintenance, and Zimbabwe has
156-399: Is a passive or semi-passive cooling strategy that requires increased air movement at night to cool the structural elements of a building. A distinction may be made between free cooling to chill water and night flushing to cool down building thermal mass . To execute night flushing, one typically keeps the building envelope closed during the day. The building structure's thermal mass acts as
182-605: Is different from Wikidata All article disambiguation pages All disambiguation pages Eastgate Centre, Harare The Eastgate Centre is a shopping centre and office block in central Harare , Zimbabwe , designed by Mick Pearce . Designed to be ventilated and cooled by entirely natural means, it was probably the first building in the world to use natural cooling to this level of sophistication. It opened in 1996 on Robert Mugabe Avenue and Second Street, and provides 5,600 m² of retail space, 26,000 m² of office space and parking for 450 cars. The Eastgate Centre's design
208-496: The additional problem that the original system and most spare parts have to be imported, squandering foreign exchange reserves. Mick Pearce, the architect, therefore took an alternative approach. Because of its altitude, Harare has a temperate climate despite being in the tropics, and the typical daily temperature swing is 10 to 14 °C. This makes a mechanical or passive cooling system a viable alternative to artificial air-conditioning. Passive cooling works by storing heat in
234-468: The building due occupancy and equipment. It includes the following design techniques: The modulation and heat dissipation techniques rely on natural heat sinks to store and remove the internal heat gains. Examples of natural sinks are night sky, earth soil, and building mass. Therefore, passive cooling techniques that use heat sinks can act to either modulate heat gain with thermal mass or dissipate heat through natural cooling strategies. Ventilation as
260-411: The building. In loud city locations, the opening of windows can create poor acoustical conditions inside the building. In humid climates, night flushing can introduce humid air, typically above 90% relative humidity during the coolest part of the night. This moisture can accumulate in the building overnight leading to increased humidity during the day leading to comfort problems and even mold growth. In
286-537: The day and venting it at night as temperatures drop. Passively cooled, Eastgate uses only 10% of the energy needed by a similar conventionally cooled building. When actively cooled, the Centre consumes 35% less energy to maintain the same temperature as a conventionally cooled building. Eastgate is emulated by London's Portcullis House (2001), opposite the Palace of Westminster . The distinctive giant chimneys on which
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#1732801803383312-418: The day when the building is occupied. Night flushing is most effective in climates with a large diurnal swing, i.e. a large difference between the daily maximum and minimum outdoor temperature. For optimal performance, the nighttime outdoor air temperature should fall well below the daytime comfort zone limit of 22 °C (72 °F), and should have low absolute or specific humidity . In hot, humid climates
338-446: The dirunial temperature swing is typically small, and the nighttime humidity stays high. Night flushing has limited effectiveness and can introduce high humidity that causes problems and can lead to high energy costs if it is removed by active systems during the day. Thus, night flushing's effectiveness is limited to sufficiently dry climates. For the night flushing strategy to be effective at reducing indoor temperature and energy usage,
364-401: The effectiveness of the natural cooling process. Such applications are also called 'hybrid cooling systems'. The techniques for passive cooling can be grouped in two main categories: Protection from or prevention of heat gains encompasses all the design techniques that minimizes the impact of solar heat gains through the building's envelope and of internal heat gains that is generated inside
390-404: The natural environment, combined with the architectural design of building components (e.g. building envelope ), rather than mechanical systems to dissipate heat. Therefore, natural cooling depends not only on the architectural design of the building but on how the site's natural resources are used as heat sinks (i.e. everything that absorbs or dissipates heat). Examples of on-site heat sinks are
416-492: The power requirements for a conventional packaged unit air-conditioner. As for interior comfort, a study found that evaporative cooling reduced inside air temperature by 9.6 °C compared to outdoor temperature. An innovative passive system uses evaporating water to cool the roof so that a major portion of solar heat does not come inside. Ancient Egypt used evaporative cooling; for instance, reeds were hung in windows and were moistened with trickling water. Evaporation from
442-543: The process of manually opening and closing windows every day can be tiresome, especially in the presence of insect screens. This problem can be eased with automated windows or ventilation louvers, such as in the Manitoba Hydro Place . Natural night flushing also requires windows to be open at night when the building is most likely unoccupied, which can raise security issues. If outdoor air is polluted, night flushing can expose occupants to harmful conditions inside
468-462: The same term [REDACTED] This disambiguation page lists articles associated with the title Eastgate Mall . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Eastgate_Mall&oldid=1225777997 " Categories : Disambiguation pages Place name disambiguation pages Hidden categories: Short description
494-426: The soil and transpiration from plants also provides cooling; the water released from the plant evaporates. Gardens and potted plants are used to drive cooling, as in the hortus of a domus , the tsubo-niwa of a machiya , and so on. Earth coupling uses the moderate and consistent temperature of the soil to act as a heat sink to cool a building through conduction . This passive cooling strategy
520-405: The study of heat transfer , radiative cooling is the process by which a body loses heat by thermal radiation . As Planck's law describes, every physical body spontaneously and continuously emits electromagnetic radiation . This design relies on the evaporative process of water to cool the incoming air while simultaneously increasing the relative humidity. A saturated filter is placed at
546-526: The supply inlet so the natural process of evaporation can cool the supply air. Apart from the energy to drive the fans, water is the only other resource required to provide conditioning to indoor spaces. The effectiveness of evaporative cooling is largely dependent on the humidity of the outside air; dryer air produces more cooling. A study of field performance results in Kuwait revealed that power requirements for an evaporative cooler are approximately 75% less than
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#1732801803383572-727: The system relies are clearly visible. To work well, the building must be very carefully designed. After computer simulation and analysis, the engineering firm Ove Arup , gave Pearce a set of rules. They said that no direct sunlight must fall on the external walls at all and the north façade [direction of summer sun] window-to-wall area must not exceed 25%. They asked for a balance between artificial and external light to minimise energy consumption and heat gain. They said all windows must be sealed because of noise pollution and unpredictable wind pressures and temperatures, relying on ducted ventilation. Above all, windows must be light filters, controlling glare, noise and security. To help with this last,
598-443: The thermal mass must be sized sufficiently and distributed over a wide enough surface area to absorb the space's daily heat gains. Also, the total air change rate must be high enough to remove the internal heat gains from the space at night. There are three ways night flushing can be achieved in a building: These three strategies are part of the ventilative cooling strategies. There are numerous benefits to using night flushing as
624-576: The upper atmosphere (night sky), the outdoor air (wind), and the earth/soil. Passive cooling is an important tool for design of buildings for climate change adaptation – reducing dependency on energy-intensive air conditioning in warming environments. Passive cooling covers all natural processes and techniques of heat dissipation and modulation without the use of energy. Some authors consider that minor and simple mechanical systems (e.g. pumps and economizers) can be integrated in passive cooling techniques, as long they are used to enhance
650-490: The windows have adjustable blinds, but Pearce also used deep overhangs to keep direct sun off windows and walls. Deep eaves are a traditional solution in Africa, shading the walls completely from the high summer sun, while allowing the lower winter sun to warm the building in the morning. Further, passive cooling systems are particularly appropriate for this part of Africa because, long before humans thought of it, passive cooling
676-511: Was being used by the local termites . Termite mounds include flues which vent through the top and sides, and the mound itself is designed to catch the breeze. As the wind blows, hot air from the main chambers below ground is drawn out of the structure, helped by termites opening or blocking tunnels to control air flow. 17°49′52″S 31°03′11″E / 17.831°S 31.053°E / -17.831; 31.053 Passive cooling Natural cooling utilizes on-site energy, available from
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