Passive systems: Heating and cooling
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s t 1. Passive Heating Systems 4 Site orientation 6 Direct Solar Gain 8 Sun Space 10 Trombe Walls 12 2. Elbphilharmonie 14 3. Passive Cooling Systems 18 Ventilation 20 Night Flushing 22 Radiative Cooling 24 Evaporation Cooling 26 Earth Coupling 28 4. Council of Santa Catarina Office 30
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I E T V A I E S S H A P When looking to construct an efficient building, the architect must consider a building that breathes on its own. Each unit that makes up the building needs to accomplish a multitude of tasks, so as a whole, the individual units work together to create a system that minimizes the building’s impact on the environment. One way this can be accomplished is Passive Heating, a system that collects, stores, and
redistributes solar energy without the use of fans, pumps, or complex controllers.1 The reason it is called a passive system is because once it is in place, it does not require any machinery to operate it, thereby minimizing the workload of other systems like HVAC units. This system heavily relies on basic building elements like walls, floors, windows, and roofs, that act in a multifunctional way, taking on as many functions as possible. There are two main parts to the system, a collector which is most commonly glass that allows solar energy to permeate into the space, and an energy storage element, also called a thermal mass, that holds on to the solar energy and releases it back into the space.2
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6 https://www.zgf.com/project/kashiwa-no-ha-smart-city/
https://sustainabilityworkshop.autodesk.com/ buildings/massing-orientation-cooling
One of the first passive systems to look at would be site orientation. Something as basic as situating the building for optimal heat management could dramatically help airflow and heat circulation through a space. To take advantage of the sun’s energy when deciding a building’s orientation within a site, a ratio of surface area of the exterior to volume of the building is used. For the most heat absorption and least amount of heat loss, this ratio needs to be as small as possible. The result, a hemisphere or cube-like shape, can be altered depending on the climate, but the building’s longest axis should be
https://sustainabilityworkshop.autodesk.com/ buildings/massing-orientation-heating
oriented e a s t to west, with maximum exposure of the south wall.3 The climate of the site can also affect the building’s site orientation. For colder climates, reducing exposure of the north, east and west walls, and increasing the thickness of the west wall can minimize heat loss. Insulation can be used in conjunction with this system on the wall facing away from the sun’s path.4 This can be achieved many ways including through fiberglass insulation, spray insulation or better insulated windows. In warmer climates, the sun
position is more overhead, so a taller building with less surface area on the roof, and shaded windows can minimize heat gains. To have greater control over heat gains and minimize temperature swings, long narrow buildings should be situated east to west.5 The need for heat and light are usually at odds with each other, so balancing glazing with thermal masses is precarious. If favoring optimal direct gain, the best choice is to use large windows on the e a s t
wall a n d smaller windows with a thermal mass on the west wall.6 This will allow the sun in to heat the space, and the back wall will absorb the excess heat during the day. To minimize temperature swings, smaller windows should be used on the west wall to minimize direct gain in the afternoon, while larger windows face the east for direct gain during the sunrise.
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https://www.wbdg.org/resources/passive-solar-heating
This system focuses on the relationship of solar energy with the contents of a space. Solar energy enters the building through glazing, and then is absorbed by the building’s contents. Heat is lost quickly this way, so a thermal mass is needed to absorb energy throughout the day.7 This action is beneficial in two ways; first, during the day the sun heats the space for free while thermal masses absorb the heat and keep the building at a comfortable temperature for occupants. Later in the day, it releases the heat absorbed earlier
to continuously heat the space.8 Some techniques used to achieve this effect are clear stories, skylights, and reflectors. When clear stories are used specifically for this purpose, they allow solar energy farther into the space and into rooms that are walled off from spaces adjacent to the exterior. Skylights can be used in a similar manner as clear stories and when used with reflectors it can either concentrate and focus solar energy or deflect it to help prevent the building from overheating in the summer.9
http://www.greenspec.co.uk/building-design/direct-solar-gain/
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10 https://archinect.com/grimshaw/project/duke-university-west-campus-union-renovation
https://www.homepower.com/articles/home-efficiency/design-construction/ ask-experts-sunspace-sizing
Not too dissimilar from greenhouse technology, a sun space is an area designed to collect heat that can be directed to the main part of the building.10 The high exposure of this area causes dramatic temperature swings and as a result creates a seasonal indoor space that is most suited for lounging or limited movement. Solar energy enters the space through south facing glazing that sits on two planes, one angled and one vertical. The sun heats the air in the space to a temperature just above the normal comfort level. That heat can then be directed through the rest of the building through windows, vents and openings. These spaces usually don’t have blinds or curtains and their main function is to heat up, so as a result, they should not be
supplied w i t h additional heat or a cooling system.11 The sun space system is largely residential because of its impracticality for year round use and its naturally limiting programming. When used commercially, it is most frequently used in food service, but sometimes architects put a twist on this traditional idea to adapt it to fit their program. Seen on the left is a rendering from a renovation on Duke University’s campus. The sun space has been opened up to allow free movement even though it sacrifices the effectiveness of its original purpose.
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https://sustainabilityworkshop.autodesk.com/buildings/trombe-wall-and-attached-sunspace
Named after the founder of this technique, Felix Trombe, this passive system is similar to direct gain, but is more beneficial when less direct light is needed.12 A thick thermal mass is placed close to south facing glazing creating a heat envelope. During the day, the intense heat is absorbed by the thermal mass, not allowing any heat through to the interior on the other side of the wall. After hours of direct solar energy, the heat is intense enough to permeate the thermal mass and heat the interior through the rest of the day.13 The Trombe system is usually
modified and supplemented with another direct gain system to allow more direct gain during the day. For example, thinner walls can be used for buildings used only during the day and into early evening, and shorter Trombe walls allow more light in and release heat for a shorter period of time.14 Changing the material to water and using water tubes allows more light in while still maintaining the capability of having a full height wall. There is a multitude of ways this system can be modified through material selection, and each one has unique benefits: concrete, brick, stone, adobe, and water.15
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E I R N U E O M M R E A D H & L I G H O P Z B R EL HE “In order to make the new Philharmonic a genuinely public attraction, it is imperative to provide not only attractive architecture but also an attractive mix of urban uses. The building complex accommodates a philharmonic hall, a chamber music hall, restaurants, bars, a panorama terrace with views of Hamburg and the harbour, apartments, a hotel and parking
facilities. T h e s e varied uses are combined in one building as they are in a city. And like a city, the two contradictory and superimposed architectures of the Kaispeicher and the Philharmonic ensure exciting, varied spatial sequences: on the one hand, the original and archaic feel of the Kaispeicher marked by its relationship to the harbour; on the other, the sumptuous, elegant world of the Philharmonic. The Kaispeicher A, designed by Werner Kallmorgen, was constructed between 1963 and 1966 and used as a warehouse until close to the end of the last century. Originally built to bear
the weight of thousands of heavy bags of cocoa beans, it now lends its solid construction to supporting the new Philharmonic. The robust, almost aloof building provides a surprisingly ideal foundation for the new philharmonic hall. It seems to be part of the landscape and is not yet really part of the city, which has now finally pushed forward to this location. The harbour warehouses of the 19th century were designed to echo the vocabulary of the city’s historical façades: their windows, foundations, gables and various decorative elements are all in keeping with the architectural style of the time. Seen from the River Elbe, they were meant to blend in with the city’s skyline despite the fact that they were uninhabited storehouses that neither required nor invited the presence of light, air and sun.”
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With a building so monumental and centered around the community and user interaction, it was imperative that a focus on user comfort was a must. On the exterior, this building uses wind deflectors and insulated glass to protect the inhabitants from the harsh German winters. The wind deflectors are part of a glass screen system that acts as a modified trombe wall so that year round the building can remain comfortable with minimal interference from other manual cooling systems. The specialized glass is one of the many multifacited basic building elements and in addition to the double layer and wind sheild, it has a coating to minimize sun exposure. The building also boasts a sheilded plaza not too dissimilar from a sunspace system that pulls warmth from the sun to heat other spaces.
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E I L V I O S O S C A P Passive heating and cooling has been around for thousands of years way before the advent of mechanical heating cooling systems were invented. It is prevalent in many ancient cultures with many of them taking into consideration solar orientation, thermal mass and most importantly ventilation in there residential buildings. The first cultures to provide evidence to
solar architecture and urban planning methods were the Greeks and the Chinese. They oriented their buildings towards the South because they wanted to provide light and warmth from the sun.24 In addition Roman bathhouses had large south facing windows to do the same as the Greeks, for warmth and light, but they used it for ventilation of steam.25 Overtime solar design was largely abandoned in Europe after the Fall of Rome, but today the rise in solar and wind are on the rise.
Natural Ventilation also k passive ventilation is usin
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Stack Ventilation also known as “chimney effect� is an alternative to cross ventilation that relies on the buoyancy of warm air to rise and exit through openings located at ceiling height. Cool air replaces the hot air through outside openings carefully placed near the floor. This is commonly used in high-rise office buildings and other commercialized buildings.
Cross Ventilation relies on wind to pass through the building for the purpose of cooling for the occupants. Requires openings on two sides of the space called inlet and outlet. The sizing of the inlet and outlet is determined on the space and placement of the building, but the sizing of both the inlet and outlet need to be the same size to allow a suction for a breezes to travel through.17
The negatives about using cross or stack ventilation is the noise and air pollution. Noise is the biggest problem with ventilation because open windows can lead in unesitory sound. Areas of high acoustic noise, like near heavy traffic zones will lead to distraction in offices, hard to hear, and will bring unhealthy air into the building and cause harm to the employees. A second problem to cross and stack ventilation is air pollution. It can’t be detected, but still can be prevented by knowing the area around the building and filters in the space. Air pollution only affects the buildings in large cities or near local factories. Air pollution can cause long term effects on the occupants in the space with sensitivity to pollution and dust.
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Night Flushing in simple terms is that is produced at night and usin the space. There are three differe flushing natural, mechanical, and
s utilizing the cool air ng that air to ventilate ent ways of night d mixed-mode
NightFlushing in simple terms is utilizing the cool air that is produced at night and using that air to ventilate the space. There are three different ways of night flushing natural, mechanical, and mixed-mode.18 The first method of night flushing is natural night flushing is when you
physically o p e n windows at night, letting wind-driven or buoyancy-driven airflow to cool the space, and then in the morning you would close the windows so you seal in the cool air that was produced overnight. This uses no mechanical systems just man power and is easy to put into action. Plus depending on the windows in the given space, it’s free. This method is commonly used in small commercial offices and other low story buildings.19 Mechanical night flushing is forcing air mechanically through ventilation ducts at night at a high airflow rate and supplying air to the space during the day at a code-required minimum airflow rate to manage the buildings temperature. Commonly used in taller commercial buildings, but the building needs to be designed around the idea and it can be an added cost the project that
the builder might not want to pay for. The final method is mixed-mode night flushing, is through a combination of natural ventilation and mechanical ventilation, also known as mixedmode ventilation, by using fans to assist the natural nighttime airflow to cool spaces. This method uses both natural and mechanical night flushing, but makes it an option to on which one you want to use depending on the season.20 The negatives about using night flushing is usability, security, reduced indoor air quality, poor room acoustics, and unwanted pests. Night flushing may seem simple, but the usability and practicality isn’t. Usually night flushing needs to be thought out in the beginning phase of the project or it can be an added cost to upgrade the building to it, but it is simple to change update an older building to the new system. The biggest problem with night flushing is the security behind it. Leaving windows open in an empty office building at night can lead to unsafe conditions to theft. It can be prevented by bars and property fencing, but doesn’t insure safety. Another problem is that it can lead to a reduced in indoor air quality because the outdoor air can’t be filtered into the space like other systems can. Finally leaving open windows can lead to unwanted pests into the workspace like mice and bugs which won’t make your employee’s to happy.21
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element of a building usually the r for ventilation. There are two type cooling, direct and indirect.
st sun exposed roof and utilizing it es of radiative
Radiative Cooling is using the most sun exposed element of a building usually the roof and utilizing it for ventilation. There are two types of radiative cooling, direct and indirect. Direct radiant cooling uses the building’s roof which acts as a heat sink to absorb the daily internal loads. The roof acts as the best heat sink because it is the greatest surface exposed to the night sky. Radiate heat transfer with the night sky will remove heat from the building roof, thus cooling the building structure. A great example of direct radiant is a roof pond. A roof pond doesn’t mean a literal pond, but can just that the roof uses water, either plastic bags filled with water or an open pond, as the heat sink while a system of movable insulation panels regulate the mode of heating or cooling. During daytime the water on the roof is protected from the solar radiation and ambient air temperature by movable insulation, which allows it to serve as a heat sink and absorb the heat generated inside through the ceiling. At night, the panels are retracted to allow nocturnal radiation between the roof pond and the night sky which removes the heat from the building.
In winter, the process is reversed so that the roof pond is allowed to absorb solar radiation during the day and release it during the night into the space below to heat the space.22 Indirect radiant cooling is a heat transfer fluid that removes heat from the building structure through radiate heat transfer with the night sky. An example of that is the use of plenum. Plenum is used between the building roof and the radiator surface. Air is drawn into the building through the plenum, cooled from the radiator, and cools the mass of the building structure and during the day, the building mass acts as a heat sink.
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Evaporation Cooling is an air conditioning unit that runs on the wind to cool your home. Hot air enters a fan unit on top of your home and passes through a cooling pad that is soaked in water to cool the air through evaporation and then a fan forces the air into the space below. This is commonly used in coastal towns with high wind speeds that can popel the fans in the units.23
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Earth coupling uses the temperature of the soil to act as a heatsink to cool a building through conduction and is effective when earth temperatures are cooler than ambient air temperature. There’s two kinds of earth coupling direct and indirect.
Direct coupling also known as “earth sheltering” occurs when a building uses earth as a buffer for the walls. The earth acts as a heat sink and can effectively mitigate temperature extremes. Earth sheltering improves the performance of building envelopes by reducing heat losses and also reduces heat gains by limiting infiltration. Indirect coupling is when a building coupled with the earth by means of earth ducts. An earth duct is a buried tube that acts as a way air to travel through before entering the building. The supply air is cooled by conductive heat transfer between the tubes and surrounding soil. Earth ducts will not perform well as a source of cooling unless the soil temperature is lower than the desired room air temperature. Earth ducts typically require long tubes to cool the supply air to an appropriate temperature before entering the building. A fan is required to draw the air from the earth duct into the interior of the building. There’s many of factors that go into earth duct such as: duct length, the amount of bends in the tubes, thickness, depth, diameter, and air velocity.
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This office was placed into a competition that focused on sustainable design and how to use the location (Brazil) as a main source of energy and inspiration. The project came in first place for the use of creative solutions to simple problems. The main exploration of the project was to focuses on the topography and its potential visual axes.26 The program is distributed in two parts: the base, which includes the auditorium, plenary halls and chambers of courses, and the tower that houses the offices. The tower has only four supports, with spans of 20 meters in the longitudinal way and 10 meters in the transverse direction. Two steel beams with 30 meters structure the pavements’ slabs through metal rods every 5 meters. Facing the sea, the position of the elevators allows all users of the building to enjoy a privileged view. In Addition allows the building to be heated by the sun rays during the day and cools during the night.27 The building also take advantage of the use of a roof pond on the lower levels to cool the larger meeting spaces (lobby,
auditorium). They also use many mechanical windows for cross ventilation especially on the coast plus using evaporation cooling systems on the roof to utilize the wind from the ocean. To enhance the visuals to the sea and to the forest through the building, some modules go beyond the basic dimension of the tower, ranging from 1 to 2 meters in balance. These advances in the modules generate terraces on the upper floors, where it proposes to use a green cover to contribute to the thermal comfort of the building, and creating a pleasant work space.
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Artmann, N. “Climatic potential for passive cooling of buildings by night-time ventilation in Europe.” Applied Energy. August 24, 2006. Accessed January 17, 2018. http://www.sciencedirect.com/science/article/pii/ S0306261906000766?via%3Dihub. Gu, Min . “Radiative Cooling: Principles, Progress, and Potentials.” Radiative Cooling: Principles, Progress, and Potentials -Hossain - 2016 - Advanced Science - Wiley Online Library. February 4, 2016. Accessed January 17, 2018. http://onlinelibrary.wiley.com/doi/10.1002/advs.201500360/references. Gupta, Neha, and Gopal Tiwari. “Review of passive heating/cooling systems of buildings.” Energy Science and Engineering,September 14, 2016. Lechner, Norbert. Heating, cooling, lighting: sustainable design methods for architects. Hoboken (N.J.): J. Wiley & Sons, 2015. Lewis , J. “Night ventilation for building cooling in summer.” Solar Energy. March 31, 1999. Accessed January 17, 2018.http://www.sciencedirect.com/science/article/pii/S0038092X97000765. “Nature & Environment Learning Centre / Bureau SLA.” ArchDaily. December 20, 2015. Accessed January 15, 2018. https://www.archdaily.com/778961/nature-and-environment-learning-centre-bureau-sla. “Passive Design Strategies.” Autodesk Sustainability Workshop. Accessed January 15, 2018. https:// sustainabilityworkshop.autodesk.com/buildings/passive-design-strategies. Sharifi, Ayyoob. “Roof ponds as passive heating and cooling systems: A systematic review.” Applied Energy. September 30,2015. Accessed January 17, 2018. http://www.sciencedirect.com/science/article/ pii/S030626191501168X?via%3Dihub6191501168X-main.pdf%3F_tid=3605d208-fbb9-11e7-aed5- 00000aab0f6c&acdnat=1516216043_9f57ae93ada6977bc5e77048d64cbed6 Maheshwari, G.P. “Energy-saving potential of an indirect evaporative cooler.” ApplieDApril 03, 2001Accessed January 17, 2018. http://www.sciencedirect.com/science/article/pii/ S0306261900000660?via%3Dihub “The Memorabilia by Xenophon.” The Memorabilia : Book III : VIII by Xenophon @ Classic Reader. Accessed January 17, 2018. http://www.classicreader.com/book/1792/25/. Jordana , Sebastian . “Regional Council of Administration / AUM arquitetos.” ArchDaily. December 18, 2010. Accessed January 17, 2018. https://www.archdaily.com/97071/regional-council-of-administration-aum- arquitetos. “Elbphilharmonie Hamburg / Herzog & de Meuron.” ArchDaily. December 25, 2016. https://www.archdaily.com/802093/elbphilharmonie-hamburg-herzog-and-de-meuron.
Lechner, Norbert. Heating, cooling, lighting: sustainable design methods for architects. Hoboken (N.J.): J. Wiley & Sons, 2015: 146 Ibid., 147. “Passive Design Strategies.” Autodesk Sustainability Workshop. Accessed January 15, 2018. https://sustainabilityworkshop.autodesk.com/ buildings/passive-design-strategies. Ibid., Passive Heating- Massing. Ibid., Passive Heating- Massing. Ibid., Passive Heating- Massing. Lechner, Heating, 147. Gupta, Neha, and Gopal Tiwari. “Review of passive heating/cooling systems of buildings.” Energy Science and Engineering, September 14, 2016. “Passive Design Strategies.” Autodesk Sustainability Workshop. Accessed January 15, 2018. https://sustainabilityworkshop.autodesk.com/ buildings/passive-design-strategies. Lechner, Heating, 158. Ibid., 159. Ibid., 152. .”Passive Design Strategies.” Autodesk Sustainability Workshop. Accessed January 15, 2018. https://sustainabilityworkshop.autodesk.com/ buildings/passive-design-strategies. Lechner, Heating,154. “Passive Design Strategies.” Autodesk Sustainability Workshop. Accessed January 15, 2018. https://sustainabilityworkshop.autodesk.com/ buildings/passive-design-strategies. “Nature & Environment Learning Centre / Bureau SLA.” ArchDaily. December 20, 2015. Accessed January 15, 2018. https://www.archdaily. com/778961/nature-and-environment-learning-centre-bureau-sla. Gu, Min . “Radiative Cooling: Principles, Progress, and Potentials.” Radiative Cooling: Principles, Progress, and Potentials - Hossain - 2016 - Advanced Science - Wiley Online Library. February 4, 2016. Accessed January 17, 2018. http://onlinelibrary.wiley.com/doi/10.1002/ advs.201500360/references. Lewis , J. “Night ventilation for building cooling in summer.” Solar Energy. March 31, 1999. Accessed January 17, 2018. http://www. sciencedirect.com/science/article/pii/S0038092X97000765. Ibid., Ventilation Ibid., Ventilation Artmann, N. “Climatic potential for passive cooling of buildings by night-time ventilation in Europe.” Applied Energy. August 24, 2006. Accessed January 17, 2018. http://www.sciencedirect.com/science/article/pii/S0306261906000766?via%3Dihub. Sharifi, Ayyoob. “Roof ponds as passive heating and cooling systems: A systematic review.” Applied Energy. September 30, 2015. Accessed January 17, 2018. http://www.sciencedirect.com/science/article/pii/S030626191501168X?via%3Dihub6191501168X-main.pdf%3F_ tid=3605d208-fbb9-11e7-aed5-00000aab0f6c&acdnat=1516216043_9f57ae93ada6977bc5e77048d64cbed6 Maheshwari, G.P. “Energy-saving potential of an indirect evaporative cooler.” Applied Energy. April 03, 2001. Accessed January 17, 2018. http://www.sciencedirect.com/science/article/pii/S0306261900000660?via%3Dihub “The Memorabilia by Xenophon.” The Memorabilia : Book III : VIII by Xenophon @ Classic Reader. Accessed January 17, 2018. http://www. classicreader.com/book/1792/25/. Ibid., Socrates Jordana , Sebastian . “Regional Council of Administration / AUM arquitetos.” ArchDaily. December 18, 2010. Accessed January 17, 2018. https://www.archdaily.com/97071/regional-council-of-administration-aum-arquitetos. Ibid., Wind
Written By: Kirstyn Nocho and Hunter Faddis
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