Erhverfsakademiet LillebĂŚlt; Architectural Technologies & Construction Management.
Passive Thermal Comfort - Guidelines for passive solar heating.
June 22, 2018 Bjarki Arnarsson Coordinator: Asthon Funck
Bachelor Project.
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Table of contents Table of contents ...................................ii Introduction ....................................... iii Chapter one: Solar geometry ..........................2 Chapter two: Thermal comfort ........................10 Chapter three: Considerations for passive solar......26 Chapter four: A brief history .......................46 References ..........................................56
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Introduction Rationale I have always been highly interested in self-sufficiency and sustainability in building design. The idea that buildings can produce enough energy for themselves, eliminating the need for alternative non-renewable energy sources, should in my opinion be the goal for every building design. While writing my bachelors dissertation I stumbled upon the concept of Passive Solar Architecture. I had never heard of passive means of harnessing solar energy and the potential benefits of this sustainable architectural method fascinated me, I instantly wanted to learn more. I also realized, after bringing up the subject to my fellow students, that most of them had limited or no knowledge at all about Passive Solar Architecture. Affordable housing has always been an interest of mine as well. By adapting passive systems to building design, running cost of houses can be significantly reduced, which is a big part in making houses more affordable. That’s where the interest in topic came from, sustainability and reduced energy consumption. I had two main objectives for this assignment. First off, to increase and broaden my own knowledge regarding passive solar heating systems. Secondly, I wanted my future colleagues and fellow students to be able to do the same. I decided the best way to achieve those objectives simultaneously was to write a guide providing the basic necessary information regarding the subject of passive solar heating, increasing my own knowledge in the process and providing others with a simple way of learning about the subject. iii
Limitations Understanding passive solar system requires basic knowledge regarding the many factors that make up the systems. Therefore, I decided to focus on quality over quantity. Of course, that resulted in oversimplifying the science behind many of the subjects but is still accurate enough to understand the overall concept of the subject.
Solar Design Solar design, or solar architecture refers to buildings and systems that were designed, in one way or another, to utilize solar radiation for energy accumulation. The term solar design can be further divided into two separate categories, called “Active Solar” and “Passive Solar”: The former category, active solar, relies on mechanical assistance to collect and convert solar radiation into energy, thermal, electric or else. The latter category, passive solar, does not rely on mechanical assistance to produce energy from solar radiation. Passive solar systems rely more on a holistic approach and integrated design of the building envelope for energy production. The building envelope is defined by all the components that separate the interior from the exterior; external walls, ground floor slabs and the roof. Those elements are then designed to fulfil as many functions as possible. For example, in passive solar iv
systems, the purpose of an external wall is not only to hold up the roof and to provide shelter from the weather, but can also act as a heat collector, a heat storage unit and has the capability to redistribute gathered heat energy from the sun to other areas of the building. By adapting passive solar principals into buildings design the various building components can attribute to energy requirements while simultaneously satisfying both their architectural and structural features. Passive solar design is used for various purposes although the most common usage of passive solar systems is for space heating. Those systems are referred to as passive solar heating systems. That is precisely what this guide is intended to explain and aid in the understanding of. The following pages of this guide include an introduction into how the concept of passive solar heating works, various systems of passive solar heating along with an explanation of functionality for each system, their advantages and disadvantages, design considerations and recommendations, and finally a brief history of the passive solar design concept.
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Chapter one: Solar geometry
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The sun Earth Solar angles Sun path The greenhouse effect
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The sun Life on earth would not exist if it wasn’t for the sun. More specifically, life would not exist on earth if it wasn´t for the atmospheres ability to capture and utilize solar radiation to warm up the planet and keep it warm enough to sustain life. The sun itself acts like a fusion reactor where atoms are fused into heavier atoms. This takes place in the core of the sun, where the necessary temperature for atoms1 to fuse is around 14.000.000 °C. The solar radiation that hits the earth is however emitted from the sun’s surface where the temperature is much colder, about 5500 °C on average. The distance between the earth and sun is just right for solar radiation to maintain temperatures warm enough to sustain life on earth
Earth The earth orbits the sun as the sun travels seemingly endlessly through time and space. It does however not orbit the sun in a perfect circle, the orbital path is an ellipse (figure 1), meaning that the distance between the earth and the sun varies depending on earths position in the ellipse. The distance varies only 3.3 percent, enough to result in a minor annual variation in the intensity of the solar radiation hitting earth and its
Figure 1
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 1
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atmosphere. The effects are however minor, they slightly moderate the temperatures differences of both summers and winters in the northern hemisphere. Because the sun lies in the plane of earth’s orbit and is very far away, the solar radiation that reaches earth is always parallel to this plane (figure 2). Not only does the earth orbit the sun, it also spins around its own1 north to south axes while those axes remain fixed. The axis and the orbital plane are not perpendicular but tilted at 23,5° off the normal of the plane. Because of this, the sun rays hit the earth at angles that constantly change throughout the year (figure 3). Subsequently, the tilt affects the earth’s climate and weather system resulting in the four seasons; Summer, fall, winter and spring. That same tilt also has a major implication for solar design because of the different angels the sunlight hits the earth throughout the year.
Figure 2
There is one day out of the year with the least amount of sunlight that falls on earth, one day with the most amount of sunlight and two days out of the year where day and night are equal. The shortest day is on the 21st of December and is known as the Winter Solstice. The longest day is on the 21st of June, known as the Summer Solstice. On March 21st, both day and night are just as long, known as the Spring Equinox. Half a year later, both day and night are just as long for the second time during the year on September 21st, known as the Fall Equinox (figure 1). For the same reasons, the hours of sunlight vary from day to day, especially in the northern and southern hemispheres where the changes in sunlight hours per day are greater at the earths poles than they are at the equator.
Figure 3 Homeintheearth.com-
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Solar Angles Altitude and Azimuth angles determine the precise location of the sun in the sky from a fixed point (figure 4). The altitude angel, measured on a vertical plane, is the combination of time of day, time of year2 and the geographical latitude, they tell the height of the sun on the sky from the fixed point. The azimuth angle, measured on a horizontal plane, defines the sun’s angular position from true south. Combining the two angles, we can pin point the suns location in the sky at any given time of any given day. On the equinoxes of spring and fall, the sun is at 90° to the surface of the equator, which is the plane or 0°. Once in that position, one square metre of sunlight entering the atmosphere heats up on square meter of the ground. If the 90° sun angle is tilted by 30°, that same square meter will only receive 87% of sunlight. The lower the sun hangs in the sky, the less solar radiation the earth will receive by square metre. This is known as the “cosine law” (figure 5) and is a principal factor to solar design.
Figure 4
Figure 5 Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 2
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Sun path From a fixed point, the sun seems to rise in the east, swing south across the sky and set in the west. If we can imagine that fixed point in the middle of a dome, and that we can track the suns path by marking the dome every hour as the sun travels through the sky above us until it sets, then we have a sun path for every hour of that day (figure 7). That information is important to architects to assist in building design. The solar path on the sky varies from day to day but seems to be the same each day of the year. The highest sun path each year is during the summer solstice and the lowest sun path at winter solstice (figure 6). The average middle path are the spring and fall equinoxes. If we continue imagining the sky dome, there is also something called a “solar window� (figure 7). The part of the sky dome where the most powerful sunrays penetrate each day is known as the solar window, outside the solar window the solar radiation is weaker. The sun path also provides the angle of sunlight hitting the building each day throughout the year, allowing designers to design a building that can utilize the sunlight in specific ways at any given time of year. Luckily, figuring out a buildings sun path has been integrated into most 3D design programs aimed at building design, so all relevant information can be extracted from such programs since most buildings in modern times are designed in such 3D programs. Nevertheless, to use the sun path to our advantage, it’s better to understand the fundamental basis of how these things work. The solar science presented so far is oversimplified to say the least, yet the information is sufficient to understand
Figure 6 WaterUniversity.com -
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Figure 7 SolarFeeds.com - http://www.solarfeeds.com/solar-
the suns role in passive solar systems and how to design accordingly.
The Greenhouse effect. When solar radiation reaches earth’s atmosphere in the form of short wavelength radiation, the radiation is absorbed and retained in earths land masses,3 bodies of water and atmosphere. Earth’s atmosphere is essentially a mixture of diverse types of gasses, some of whom are greenhouse gases. Greenhouse gases are radiatively active, meaning they will absorb the short wavelength radiation and re-radiating4 the same radiation in to long wavelength radiation. The long wavelength radiation is then mostly trapped within the atmosphere because of the greenhouse gases, keeping the planet warm enough to sustain life (figure 8). Those series of events are what make up the natural phenomena which we call “The greenhouse effect”. Similar effects can be achieved on a much smaller scale, a house for example. In Figure 10, a section view of a typical Chinese greenhouse can be seen. The south facing roof is an aperture that allows sunlight into the whole building while the north facing wall and roof provide plain soil. Just like solar radiation gets trapped within the atmosphere, it gets trapped within the greenhouse, generating enough heat energy to grow plants all year long. However, what happens in a greenhouse is not the same thing that happens to earth on the larger scale. In
Figure 8
David Bergman (2012) Sustainable Design: A critical guide. Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 3 4
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the greenhouse, the heat energy is retained by the lack of airflow while earth gets its warmth purely from solar radiation trapped in the atmosphere and in the earth itself. Buildings in general can utilize the same principal design features as the greenhouse does to harness solar energy for heating (figure 9). That is the fundamental principal of passive solar heating, to allow solar radiation into a controlled environment and accumulating heat energy from it.
Figure 9 3m.com - http://www.3m.co.uk/intl/uk/3Mworldly-
Figure 10 9
Chapter two: Thermal comfort
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Thermal Mass The Three Main Systems Other passive solar heating systems
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Passive solar systems are primarily used for heating, ventilation and daylighting. Due to the holistic approach of the passive solar concept, the three usually work together in one way or another.5 Passive solar heating systems have at least two elements working together, a collector and storage: The collector, as the name indicates, collects the solar radiation. Usually the collector is a south facing glazed glass window capable of allowing solar radiation to penetrate one way but not the other, meaning that the window allows solar radiation into the space while simultaneously blocking it from getting back out of the space. The storage, again as the name indicated, is an element capable of absorbing the solar radiation and storing it for later use. Those elements are also known as “Thermal Masses�. A thermal mass is a dense material that has high heat conductivity as well, such as stone, concrete or bodies of water. However, a further elaborated system includes a few more steppes added to the process to essentially achieve the same outcome, the five components needed for the benefits to function to the best of their abilities are as follows: Aperture; is the opening which allows the solar radiation to enter the space, usually a glazed glass window although technically it could be anything that allows the sun to enter the room.
Figure 11
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Absorber; also referred to as the Collector, is an element with high heat conductivity capable of collecting the solar radiation and transferring it to heat energy. Could be any material that heats up when the sun shines on it. Thermal mass; also referred to as the storage, is the building component that stores the accumulated heat energy6 from the absorber. The thermal mass gathers the heat during the day, while the sun is shining, and emits the heat energy back into the air during the night, when the sun is not shining. Distributor; is the mechanism or system that distributes the gathered heat energy to other spaces of the building. This can be achieved by ventilation systems, natural or mechanical, among other methods. Controls; are all building elements and components that either block or provide access for the sunlight into the building, depending on which is preferred. A roofs overhang can for example allow the winter sun to shine into the space and block the summer sun from entering that same space. These same components are used for passive solar solutions in one way or another (figures 11 & 12), for daylighting, for natural ventilation and for thermal comfort. There are many passive solar solutions, most further described in the following chapters, that utilize these steps in diverse ways.
Figure 12
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David Bergman (2012) Sustainable Design: A critical guide.
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Thermal mass The thermal mass is the most vital component in passive solar systems aside from the sun of course. Thermal masses are capable of absorbing and storing7 solar radiation in the form of heat, temporarily trapped within the mass itself. When the sun is shining, the thermal mass absorbs the solar radiation and retains it in the form of heat. The thermal mass thickness and volume controls how much heat is gathered and when it is emitted. Therefore, there are several types of systems with various purposes that all rely on the potential properties of the thermal mass and solar radiation.
The three main systems Most of passive solar systems are used for the advantages of space heating (figure 13). The three most commonly used systems are a) Direct Gain, b) Trombe Wall and c) the Sunspace. Each system will be further elaborated on in the following sections.8 With a focus on explaining each system separately, the systems functionality, cost, advantages & disadvantages and general relevant information about each system.
Figure 13 David Bergman (2012) Sustainable Design: A critical guide. Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 7 8
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Direct-gain Direct gain systems are easily defined, they consist of a south facing aperture, a thermal mass floor and sometimes an absorber, depending on the material of the mass, concrete floors don’t need an absorber for example. Together they absorb, retain and emit the radiation in the form of heat. Essentially every south orientated window is in one way or another a direct gain system (figure 14). Simply by allowing sunshine into the building will influence internal temperatures. Therefore, this system is the most common passive solar heating system. The system is designed to mitigate diurnal temperature swings of the interior, keeping temperatures even during both day and night, preventing overcooling and overheating. Of the many systems, the direct gain system is capable of the most energy accumulation and is the most cost effective.8 The large south facing windows the system requires supports a better daylighting design as well. Therefore, these systems are ideal for schools, small offices and other similar buildings although they can very well be designed for dwellings as well. On the other hand, overabundance of light in buildings can be problematic. Thermal mass floors require the part of the floor that receives sunlight to be clear of any furniture, carpets and anything that would block the sun. If the thermal mass is designed incorrectly, there is a risk of overheating and when the system is the only source of heat, temperature swings of about 6°C on average must be tolerated.
Figure 15
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Trombe wall This system is also known as “Thermal-Storage wall system.” That term however, is not as accurate because not all thermal storage walls can be considered a Trombe wall. The “Trombe wall” system draws its name from the French professor Felix Trombe, who developed this technique in 1966. The Trombe wall is a type of an Indirect Gain system. Indirect gain systems are defined by the placement of the thermal mass between the sun and the heated area9. In this case, heat is transferred to the living space by conduction. Typically, the thermal mass in indirect gain systems is a wall, the mass absorbs solar radiation from one side and transmits heat on the other side.
Figure 15 Figure 16
The system consists of a glazed south facing window placed directly in front of, and quite close to, a vertical thermal mass wall (figures 15 & 16). This system is preferred when only the suns heat is desired but not the actual sunlight. The mass wall is coated or painted in dark heat in the narrow space between the wall and the window, which is absorbed by the mass. Usually, when Trombe wall systems are chosen, they are intended to collect heat during the day and to provide thermal comfort during the night. Therefore, the thermal mass is thicker, usually up to 30 cm. The walls thickness provides the desired result of collecting heat during
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 9
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Figure 87
the day and emitting heat during the night, having little or no effect on thermal comfort during the day. The Trombe wall system does, of course, have its advantages and disadvantages as well. Aside from being slightly more expensive, both daylight and views are limited because of the vertical position of the thermal mass. Therefore, the Trombe wall system10 is mostly used in combination with a direct gain system, it is seldomly used on its own. When combined with another system, such as direct gain, the Trombe wall can be placed between windows or as a parapet wall, underneath windows. The direct gain provides heat in the morning, thermal comfort during the day, daylight into the building and views of the exterior, while the Trombe wall provides heat and thermal comfort during the night. Considering the systems advantages, it can handle higher heating loads, provides higher temperature for thermal comfort and works well in conjunction with the direct gain system limiting lighting levels and for overall thermal comfort.
Sunspace A sunspace is essentially a greenhouse attached to the side of a building, designed to collect heat from solar radiation to warm up the building11 it is attached to. The space usually consists of large, south facing windows and a thermal mass. Aside from contributing to thermal 10 11
David Bergman (2012) Sustainable Design: A critical guide. David Bergman (2012) Sustainable Design: A critical guide.
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comfort, the sunspace can provide extra living space and acts as a thermal buffer for the main building. As can be seen in figure 17, sunspaces can be designed in 3 ways, attached to the building, Semi-enclosed or completely enclosed. Different from direct gain systems and the Trombe wall, the sunspace should be designed as a separate thermal zone. That way, temperatures can be allowed to swing more widely to provide more heat. Vents, doors, windows or any operable openings are placed in the separating wall between the sunspace and the house to control12 the airflow of warm air into the house. During the day, vents are kept open to allow airflow of warm air (figure 18) and during the night, vents are closed to retain the heat and the sunspace acts as a thermal buffer (figure 19), lessening heat loss from the main building.
Figure 17
The area of vents, doors and windows in the common wall should be at least and preferably more than 16% of the glazed area to allow heat flow effortlessly into the main building. Figure 18
The glazed area in the sunspace itself also needs operable windows or vents to prevent overheating and allow airflow to cool down the space. The vents or windows in the glazing should be two, one close to the ground and the other close to the ceiling, both of whom should be 8% of the glazed area. If mechanical fans are used for ventilating the sunspace, the vents can be designed smaller. The thermal mass can be placed both in the floor and in the common wall that separates the sunspace from the Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 12
Figure 19 18
building, all depending on the desired result of the sunspace. If the sunspace is designed primarily as a solar heat collector, the thermal mass is smaller so more of the heat ends up in the house. If the sunspace is designed to function as an extra living space as well (figure 20), the mass is thicker to lessen temperature swings in the sunspace. Placing a thermal mass in the common separating wall depends on the climate and the buildings location. If the climate is temperate, a thermal mass in the common wall helps to mitigate temperatures swings both in the sunspace and in the house. The thermal mass provides enough warmth to prevent the sunspace from freezing and provides thermal comfort to the main building simultaneously. In colder climates, the main purpose of the passive system is to provide and retain heat, it would be better to insulate the separating wall, so heat can be collected from the sunspace and heat loss can be efficiently prevented simultaneously. Since the sunspace is separated from the house and is seen as a secondary extra living space, the sunspace does not have to and should not be heated up by any other means than by solar radiation. Because of its design, the loss of energy would be higher than the amount of energy the sunspace can retain and provide, so heating up the sunspace with alternative energy resources would proof to be counter effective. Figure 20
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Other passive solar systems The three most common and arguably better systems have been described so far and in detail. There are however other less used systems, a few of them explained in the following paragraphs.
Indirect gain system In this system, solar radiation is used to heat up a building element that later heats up the space on the opposite side. For example, a sheet of glass in front of a brick wall will heat up both the space between the glass and the wall and the wall itself13, the wall absorbs solar radiation during the day and emits it into the space on the opposite side during the night. The right glazing allows solar radiation through the glass and into the building but does not allow the solar radiation to exit the same way it came in thus the radiation is mostly absorbed by the mass. A Trombe wall is an excellent example for Indirect gain systems. The “Roof pond system” and the “Roof radiant trap system”, explained in the following paragraphs, are both examples of indirect gain systems as well.
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David Bergman (2012) Sustainable Design: A critical guide.
Roof ponds The name of this system is confusing to say the least, it does not include an actual pond on the roof for heating. The system consists of dark coloured water containers, black plastic bags for example, located on the roof, then movable14 insulation closes the roof during the night, keeping the water warm. The water containers are held up by a metal deck roof, the sun shines on the water containers which heat up quickly and radiate heat down through the ceiling, providing warmth from above to the living area (figure 21). It’s an attractive system and seems simple to implement and use but in this case the disadvantages outweigh the advantages. The system requires a flat roof, which is a disadvantage for cold climates where snowfall is common and according to the cosine law, the flat roof will receive less solar radiation than a sloped roof, unless the house is built close to the equator but the tropical climate at the equator has no need for heating systems. No one has yet been able to design movable insulation panels for the roof. Water is heavy, so the static system would have to be better which is more expensive and then there is the possibility of leakage. Therefore, roof ponds are not a popular solar heating system and cannot really be recommended.
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects.
Figure 21
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Radiant roof trap The Radiant roof trap (figure 22) was developed by Professor B. Givoni, he saw the potential of the roof pond system while he also realized its flaws but was inspired by heating from above15. A slightly tilted south facing clerestory window in the roof allows solar radiation into the roof space which is absorbed by the black painted,14 or coated, concrete ceiling slab which emits heat efficiently to the living space below. The clerestory window is then equipped with a shutter to insulate the window during the night. The roof above the concrete slab is then properly insulated and airflow limited to counter effect heat loss and to aim the heat down into the living area.
Figure 22
Lightweight collecting walls Lightweight collecting wall (figure 23) system is unique from other systems because it does not have a thermal mass. The system consists of an aperture and an absorber15. This system is designed to benefit buildings that are occupied during the day and empty during the night, such as schools and office buildings. A low standing lightweight wall, with a dark coloured absorber facing the window, is placed close to south facing windows. The wall then has a gap between the lower edge
Figure 23
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of the wall and the floor. The air between the wall and the window heats up and rises while colder air replaces the warm air from the gap at the bottom, creating the means for circulation of heated air.
Rock bed Essentially rock beds are heat storage mediums, they are not a heating system on their own but an add-on to heating systems, passive or active. Rocks, or pebbles, are placed in an insulated container (figure 25) that is connected to the heat accumulation system16. Usually the heat energy is transferred to the rock bed by airflow, water can be used as well although air is preferable as they are simpler in operation, lower in first cost and lower maintenance costs.
Figure 24
Rock beds can be used efficiently for both short-term heat storage and long-term heat storage. The passive systems described up to this point are all classified with short-term heat storage. Short-term heat storage usually does not store heat for more than a day and is designed for daily functionality. Long-term heat storage is designed to collect and store heat during summer to be utilized in winter, sometimes referred to as seasonal storage. Temperatures in long-term heat storage rock beds are monitored to make sure their temperatures stay even and Figure 25 Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects 16
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warm while the heat is stored. In the colder months, when the heat is required it can be retrieved by simple airflow. This add-on to passive solar heating systems can be very advantageous for cloudy winter days to provide heat when passive systems don’t work due to lack of sunlight.
Isolated gain In isolated gain systems both collection and storage of solar radiation is thermally isolated from the building, that control the heat flow into the building17. Usually consisting of separate components and not necessarily a part of the building itself, allowing more flexibility in building design. The most common example of isolated gain systems is the convective loop system. (figure 28). Sunspaces that are completely isolated from the building they are attached to could also be classified as an isolated gain system. Solar chimneys (figure 27) are another example of isolated gain heating systems.
CLEAR.com - https://newlearn.info/packages/clear/thermal/buildings/passive_sys tem/passive_heating/isolated_gain.html - 22.06.18 17
Figure 26 24
Mixed use systems There is no requirement to choose only one system for space heating. The concept of passive solar relies on a holistic approach when it comes to building design, in most cases that includes a mixture of both passive and active systems. In some cases, a mixture of passive systems as well. Figures 27 and 29 show examples of a mixture Direct gain and Trombe wall.
Figure 27 Iklimnet.com - http://www.iklimnet.com/save/passive_solar_heating.html -
Figure 28
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Chapter three: Considerations for passive solar
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The Three Tier Approach Location Orientation Glazing Materials Floor plans Controls
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To determine whether passive solar design is a viable option for a buildings design or not, there are several factors to consider which will be further elaborated on in this chapter. Each of them relevant to achieve the best possible design solution. The following guide lines provide general information and considerations that should be kept in mind regarding all passive solar heating systems and mainly the three most common systems, Direct gain, Trombe wall and the Sunspace.
The three-tier approach Figure 30 Unfortunately, passive solar heating is not an exact science and it is difficult to meet the requirements for thermal comfort by relying only on passive systems alone, although in certain circumstances it can be achieved. Most buildings that integrate passive design solutions also integrate active measures to ensure that the desired results can be achieved. Buildings often rely on a mixture of both passive and active systems for their energy requirements, those buildings are said to have a “Mixed use� system. The three-tier approach (figures 30 & 31) is a tool for sustainable design strategies. The first step of the approach focuses on reducing the need for energy usage. The second step focuses on providing as much of the required energy as possible from passive and sustainable sources. The third step focuses on providing the rest of the required energy by other than passive means. The objective of the tool is to minimize energy consumption
Figure 31
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from non-renewable mechanical systems.
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In this case, the three-tier approach has been adopted for space heating of buildings; The first tier is “heat retention�, meaning the building envelope should be insulated sufficiently in accordance with the local climate to minimize heat loss to the furthest extent possible. The next tier, the next step of the process is integrating passive solar heating systems into the building design18, limiting the need for additional mechanically assisted space heaters. The third and last tier in the approach is mechanical heating added to achieve the minimum standards for thermal comfort, provided the first two tiers do not achieve the standards on their own. Usually the need for mechanical system has been lowered significantly by adapting building design to this approach. In the united states, passive solar heating systems have been recorded to provide anywhere from 60 – 80% of the heat required for thermal comfort. Of course, that percentage varies according to global location, but it does indicate how financially beneficial passive solar solutions can be.
Location Figure 32 Precise geographical location of the building is important knowledge to the Architects and designers, the Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 18
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location is what they need to figure out the sun path for the building. The plot, the layout of the land and the environment surrounding the plot are of importance as well (figure 32) and a thorough site analysis should always be made before the design phase of the building. There could be objects or buildings in the surrounding environment that will block sunlight for parts of the plot, the plot itself might be sloped in an inconvenient direction and an array of potential problems that can affect the buildings design, forcing architects to design around those potential problems. These are classic problems and not only applicable when it comes to solar design, all good architects and designers will, or should, analyse the plot to find the best possible spot for the building, considering all aspects of the plot and its surroundings.
Climate Having determined the buildings location, the climate zone of the building should be determined and especially the buildings local climate. The climate zone refers to the 4 major climates that divide the earth.
Figure 33
The Tropical zone, spanning 23.5° on each side of the equator. The Subtropics, spanning from 23.5° to 40° of the globe. The Temperate zone, spanning19 from 40° to 60°
Thomas Steiner, https://content.meteoblue.com/en/meteoscool/generalclimate-zones, Meteoblue.com 19
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of the globe. And finally, the cold zones; subpolar and polar zones, spanning from 60° to 90° of the globe (figure 33). Each climate zone will provide relevant information regarding external temperatures, weather throughout the year and other useful information necessary for architects and designers for the building design. The local climate of the area (figure 34) is just as important and often provides more accurate information regarding the weather, external diurnal temperatures, the surrounding nature and other relevant information. The local climate can, in some cases, change drastically from plot to plot and should be analysed individually for every single project. As an example, the building plot might be located on the southern side of a mountain that happens to be close to the ocean as well. The mountain then provides shelter from frosty winter winds blowing from the north. Simultaneously, the mountain gathers condensation from the ocean causing it to rain frequently in the area. Essentially, all information regarding the plot, it’s surroundings, the climate zone, the local climate in the area and other natural phenomena that might affect the building design in one way or another important for architects and designers to have before they start designing.
Figure 34
Orientation “Orientation is 80 percent of passive solar design,” – Doug Balcomb. 31
For the passive solar heating systems to function to the best of their ability, the glazing should face true south. This is the general rule of thumb regarding orientation. However, the passive systems will still work if the southern façade is orientated up to 45 degrees to either east or west from the true south orientation, but they won’t work as well as if they were orientated due true south. This is important to remember because a true south orientation is not always going to be a possibility due to the buildings location and the surrounding area in question. Like most rules, this one has it´s exceptions as well. In some cases, a true south orientation is not the best orientation. For example, if the building is occupied early in the day and empty in the afternoon and20 evening, like a kindergarten or an office building, then orientating the building 30 degrees due east of the true south orientation is better. The adjusted orientation then provides access to the morning sun and blocks access for the evening sun. This way, the passive solar system morning, when the building is occupied. In similar building which are mainly occupied in the morning and early in the day, a combination of systems might be the best option, heating can be achieved in the morning by a direct gain system and a Trombe wall system can be designed to prevent over heating in the afternoon and charge from the afternoon sun to provide heat during the night. Same principals regarding orientation apply for residential buildings or buildings that are mainly occupied in the afternoon, evening and night. For the purpose of having a better access to sunlight during the hours the building is occupied a slight adjustment to
Figure 35
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the buildings orientation of the southern faรงade by 10 degrees to the west will provide the desired result as long as providing a view of the sunset. Areas that experience morning fog or cloudy mornings also benefit from adjusting the orientation slightly west of south. The buildings surrounding area sometimes shade the buildings southern faรงade, be it trees or buildings on neighbouring plots or anything that will cast a shadow on the buildings southern faรงade. In those scenarios adjusting the southern orientation to either east or west to get away from the shadows is recommended.
Glazing There are two dominating factors to consider when it comes to selecting glazing for windows in passive solar heating systems. The glazing must allow as much of solar radiation as possible to shine into the building and should be insulated21 sufficiently to minimize heat loss. With those factors in mind, Clear glazing performs the best. With the ability to transmit about 90% of solar radiation into the building. Tinted glass, or heat20 absorbing glass, does not perform as well but is still capable of transmitting up to 80% of the radiation into the building. Reflective glazing cannot be considered a viable option where only about 50% of solar radiation transmits through and into the building.
Figure 36
21
David Bergman (2012) Sustainable Design: A critical guide.
33
The demand for thermal qualities of the glazing depend largely on the climate and external temperatures. Generally, as the climate grows colder, the better the thermal performance of the glazing needs to be. Single-pane glazing is mostly a part of history and only the most moderate climates can get away with using them. Insulated, or thermal-pane, glass has two panes with an air gap between the two (figure 37). The air has insulating qualities and significantly reduces heat loss compared to single-pane glazing. The insulated glass has become the minimum required glazing for houses in most of the world. To further enhance the thermal performance of the insulated glass, the air in the airgap can be replaced with other denser gases, such as argon or krypton, that have better insulating qualities than air. Those types of glazing are referred to simply as gas-filled glazing. Thermal performance can also be enhanced with triplepane glazing, gas-filled triple-pane glazing (figure 38), thermal-break glazing, low-emissivity glazing among other options. The is a cost issue with insulated glazing, the better the thermal performance of the glazing is, the more expensive the glazing becomes. So, for passive solar heating, the glazing should be clear and sufficiently insulating compared to climate.
Figure 37
Slope of Glazing To absorb the most sunlight, the glazing should ideally be sloped parallel the suns position in the sky during Figure 38
34
the winter solstice, presumably the coldest day of the year. If the suns position during the winter solstice shines at 23 degrees in the sky, the glazing should be sloped by 23 degrees. Although that’s ideal for absorbing the most of solar radiation as possible, sloping the windows does create more problems than it solves22. Therefore, vertical glazing is preferred. Vertical windows are less expensive, easier to fit with night time insulation, easier to shade both inside and outside and vertical windows have proven to collect more heat than sloped ones do when sunshine is reflected into the building by its surroundings.
Amount of glazing As previously discussed, passive solar systems are not an exact science. That is no exception when it comes to the topic of “The ratio of glazing compared to thermal mass�, or how large should the windows that shine on the thermal mass be in comparison to the volume of the thermal mass itself. Different systems have different values to the formula, simply because they function differently, some systems have guidelines or formulas that indicate values that are somewhat accurate.
Figure 39
General guidelines for direct gain systems, considering they have a thermal mass floor of roughly 10 cm are as follows; When south facing glazing is approximately 7% of a buildings total floor area, no additional thermal Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 22
35
mass is needed, the building elements already in place provide enough thermal23 mass properties for that much glazing. Furthermore, 45.5 m² of thermal mass flooring should be added for every 1 m² of glazing that is that is added, 5.5 m² in direct sunlight and the other 40 m² out of direct sunlight but on the same floor level. For Trombe wall system, most guidelines state that the glazing should cover as much of the thermal mass as possible and the space between the glazing and the absorbing mass should be no more than 5cm. For sunspaces the general guidelines state that if the sunspace is to be used as a secondary living area as well, the thermal mass should be thick enough to balance temperatures in the sunspace, if the sunspace is not designed as a secondary living area the mass should be thinner to achieve higher temperatures within the sunspace. Since the sunspace is designed as a separate thermal zone that can be connected or disconnected from the main building as the occupants pleases, overheating and overcooling in sunspaces is an issue that can easily be ignored without compromising thermal comfort in the main building. In colder climates the wall separating the sunspace and the living area should be insulated but in warmer climates the wall could be set up as a Trombe wall for additional night time warmth.
Figure 40 Green home building.com, http://www.greenhomebuilding.com/QandA/solarheat/mass.h tm, Ken Haggard. 23
36
Materials What defines a good thermal mass is the combination of three essential factors. Those factors are high materials density, high specific heat capacity and low thermal conductivity. The amount of heat a material can store in every kilogram of mass is referred to as the materials Specific heat capacity. The density of materials is determined by the weight of one cubic meter of said material. Thermal conductivity measures how fast heat travels through materials. The ideal thermal mass is high in density and heat capacity but low on thermal conductivity. The high density and heat capacity allow the mass to contain a lot of heat and the low thermal conductivity ensures that the mass retains and slowly emits the heat once the air temperature drops below the temperature of the mass. Judging by specific heat capacity, the capability to retain heat, water is the best material to use for thermal mass performances. Using water in the design of buildings proposes all sorts of other design issues that outweigh the positive space heating potential that water has. For constructing dwellings and infrastructures we would rather rely on dense, solid construction materials that can serve their structural purposes as well as being able to function as a thermal mass. Concrete is by far the most comfortable thermal mass material to use in the modern times, it has great thermal properties and is easy to implement into building design.
37
Size Because of the thermal masses potential to mitigate temperature swings during both day and night, one might think the more thermal mass you have, the better it is for thermal comfort. However, research and scientific observations indicate a different result, increasing thermal mass volume reduces temperature swings until a point is reached where adding to the masses volume has no real influence on the temperature swings. In some cases,24 if the mass has too much volume, its ability to mitigate heat is lost completely and the mass actively cools down the building instead. The thermal mass volume must be calculated and adapted to each individual building design although there are guide lines for both the ideal thickness and volume of thermal masses, depending on the thermal mass material, climate, diurnal temperatures and which passive solar system has been chosen. The average diurnal range of temperature on its own is a good indicator for quality of the thermal mass needed, shown in table 2. This should only be considered as a rule of thumb, of course every project should calculate specifically the mass needed for better results. High mass buildings are more applicable for passive solar systems space heating systems simply because of the masses ability to mitigate temperatures. Low mass wooden buildings should have less mass in their passive solar systems to counter over heating issues.
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 24
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Time lag The time lag is applicable in indirect gain systems, such as a Trombe wall, where radiation is absorbed on one side of the thermal mass and heat energy released on the other side of the mass. The time lag refers to the amount of time it takes the radiation25 to flow through the mass. In other words, how long it takes heat to travel from one side of the mass to the other. The mass will not emit warmth to the adjacent living area until the radiation has passed through it, heating up the whole mass, only then it starts to emit warmth to the other side. The time lag is directly associated and depends on the material chosen for the thermal mass, that materials heat conductivity and density, its thickness, exposure to air movement and air speed, temperature differences on each side of the mass and finally the surface materials on the mass itself, such as coating, colour and texture. Time lag for selected building materials can be viewed in table three. Buildings like the one in the figure 41 are often found in warmer climates. Structures with their sole opening facing south, allowing the sunshine to warm up the adobe thermal mass floors for night time warmth. Furthermore, the adobe walls keep the interior tempered during the day while absorbing solar radiation to emit for night time warmth, relying on the Time lag effect.
YourHome.gov.au, http://www.yourhome.gov.au/passivedesign/passive-solar-heating, Chris Reardon, Max Mosher, Dick Clarke. 25
Figure 41 39
Floor Plans When a building is designed with passive solar principals in mind, the southern faรงade will provide a lot of sunlight into the building. That opens the possibility to design the living spaces to take advantages of that fact (figure 42). A general guide line regarding a buildings floor plans is to design all living areas in the southern part and to place bedrooms, toilets, utility and other rooms in the northern part of the building. This way the living areas will have better access to sun and daylight26 while the other rooms, that do not have as much of daylight requirements, can be in the northern part. Kitchens placed in the south-west corner of the building will receive sunlight in the morning. The living room in the south-east corner will provide a view of the sunset and allow the evening sun into that area. Providing an area within buildings where individuals can stay indoors and enjoy the sunlight greatly improves the indoor climate of the building, which has been shown to benefit both the physical and mental health of the buildings occupants. A principal factor to keep in mind when designing buildings that take advantage of passive solar heating is to distribute the south-faced glazing proportionally through the different living areas within the building itself to counter heat loss and provide space heating for as much of the building as possible. The image to the left shows an example of a passive solar building that respects those principles. Figure 42 26
40
David Bergman (2012) Sustainable Design: A critical guide.
Controls Controls are best described by their objective, to allow solar radiation into a building when it is needed and to minimize it when it is not. The controls are either integrated as a part of the building itself or an added component, sometimes maneuverable.
Shading Passive solar heating is designed to function best during the colder months of the year. During the warmer months of the year system is likely to cause overheating, unless proper shading is provided during summer, either integrated into the building design or otherwise acquired. Shade providing devices are divided into two categories; Fixed exterior shading devices and movable shading devises. Orientation is the key to determining which shading devise works best for each side of the building (figure 43). On south facing facades a vertical overhang designed to allow the winter sun in while blocking the summer sun from entering. For east and west facing faรงades, the overhang is still a good option yet not as effective,
Figure 43 41
vertical elements in front of windows in combination with overhangs is better. Preferably east and west facing windows should not be used when27 proper shading is important, it would be better to face the windows either north or south if they must be used. The overhang is somewhat useless when it comes to north facing windows, the preferred shading option for that orientation are thin but long vertical fins, spanning the height of the window. In scenarios where there is little space for overhangs, horizontal louvres can work just as well, if they are designed correctly of course. Movable shading devises can be both mechanical or not, some automated to move and adjust their position on daily bases, designed to provide shade precisely where shade is needed each day. Of course, mechanical shading devises are more expensive, some tend to be noisy and they require more maintenance. Manually operable shading devises, that require only two simple adjustments per year, are sometimes just as effective, do not cost much, they aren’t noisy and require next to no maintenance.
Reflectors Reflectors are reflecting surfaces designed to reflect light in a specific direction. In this case, reflectors are placed outside of buildings to reflect more sunlight into the building and aid in the collection of solar radiation. The best reflectors are specular reflectors,
Figure 44
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 27
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they have a mirror like surface with high reflecting probabilities. In colder climates, where large windows sizes could compromise the thermal performance of a building, reflectors can be a great solution. Allowing designers to counter both winter heat loss and summer heat gain by minimizing the size28 of windows in the southern façade because the reflectors will provide the solar radiation lost to the windows size. The size and length of reflectors are determined by the position of the sun during the winter solstice, January 21 at 12 o’clock noon specifically. The suns position in the sky during the winter solstice should be able to shine just under the top of the window. If summer sun is not to be reflected into the building, the reflector should be tilted away from the window by an angle that roughly equals the latitude of the site, provided the reflectors cannot be removed.
Figure 45
Natural controls Deciduous trees, planted on a buildings south-west and south-east side, although should not be located directly
Figure 46
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 28
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to the south of windows29, can provide both shade and diffuse solar radiation in warm summer months while they allow the sun to shine into the building during colder winter months, after their leaves have fallen (figure 46). Coniferous, or evergreen, trees in the colder climates can provide shelter from the wind when planted close to and around the northern faรงade, depending on latitude, they can also provide shade from the high summer sun. Any bodies of water such as ponds or lakes located around the southern side of the building will act as a natural reflector of sunlight. Even frozen water, snow reradiates and reflects solar radiation in all directions.
Night insulation
Figure 47
Night insulation (figure 47) is another interesting control option when designing buildings with passive solar heating, especially in cold climates and is great for conservation of energy. The principal function of the method is to provide insulation for windows during the night, then28 retract and allow sunshine through the window in day time. The design of night time insulation is usually integrated with other possible functional abilities, such as shading or reflecting sunlight during daytime, making use of the control both day and night.
29
44
David Bergman (2012) Sustainable Design: A critical guide.
45
Chapter four: A brief history
46
China Ancient Greece Rome European revival America Modern Passive Solar
47
Before humanity started to rely on mechanical assistance to power up and keep their dwellings warm, we relied on our surrounding environment and our ability to manipulate several natural phenomena to keep our dwellings warm and pleasant. Looking back through human history, the existing archaeological evidence tells us that there are numerous ancient cultures that realized, along with having some basic understanding of orientation, material choice and human ingenuity, that they could use the sun to their benefit to both warm up and keep their dwellings temperate. Ancient Greece, the Roman empire, China and the Native Americans are a few of those cultures.
China
Figure 48 48
Archaeological evidence dating back roughly 6000 years show that Neolithic Chinese villages had the only opening to their dwellings facing south. Their dwelling at the time are considered to have been mud built huts with thatched roofs. It is speculated that this southern orientation of the huts entrance was intended to allow the low winter sun to shine into the huts to aid in their thermal performance. The evidence also suggests the thatched roofs traditionally have a large overhang that would have been capable of blocking the summer sun, keeping the huts cool during summer. Somewhere around 2000 years later, or around 4000 years ago, the principal of southern orientation began to show in urban planning in China. The Chinese urban planners made sure every major street of cities and towns ran from east to west. This straightforward design principal ensured every
dwelling an exposed southern façade that could be utilized for supplementary heating by passive solar design (figure 48). The principal became a tradition in China and can be seen in both ancient and more recent Chinese towns and cities.
Ancient Greece The Greeks designed their dwellings in a way where they allowed the sun to warm up their homes, much like the Chinese did.30 Archaeological evidence (figure 49) found in Greece dating back to the fifth century B.C shows that every dwelling, no matter the location, rural, in a town or city was designed around the passive solar architecture. Historical Greek scripture supports this evidence as well, for example in Aristotle’s notes, where builders where made sure to shelter the northern side of the house from the cold northern winter winds. Socrates also noted that houses that look towards the south can warm up the south oriented side of the building. Those are two very important aspects of passive solar architecture, sheltering the northern façade and allowing the sun into the building through southern exposures. They did however have a major problem with the method at the time, the heat that was gained was lost just as quickly because the windows were simply holes in the walls with no screen or glass what so ever to trap the heat inside, allowing the heat to escape almost as quickly as it was gained. Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects.
Figure 49
30
49
Rome It wasn´t until the Roman empire came along that the problem the Greek’s faced was solved, they were the first to use glass for their windows. In other words, they were able to trap the heat gained from sunshine inside their dwelling. Today we know this phenomenon as the Greenhouse Effect, which will be further elaborated on and explained in the following sections.
Figure 50
At the time of the Roman empire, this revelation was revolutionary, and the people found several ways of utilizing this method of energy accumulation. One of those and perhaps the most recognized one from the time of the Roman empire was the Heliocaminus (figure 50), sort of a sunroom or a sunspace. The word Heliocaminus literally translates to “solar furnace”.31 The structure was designed with thick walls and minimum openings in all directions but south, the southern façade had large window, designed to capture solar heat all day long. The Heliocaminus was used for many purposes, added to dwellings, allowing occupants to plant and produce vegetables and fruits all year long, providing an allyear-long food source. Perhaps the most recognised use of the structure was as a Roman bathhouse. Furthermore, the designed offered under floor natural ventilation by convective air flow. Unfortunately, the tradition and knowledge of constructing dwelling that utilized passive solar design principals was lost with the fall of the Roman empire and will not be seen in European history again for over a thousand years.
Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 31
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The European revival The next time passive solar design principles were used for dwellings in Europe was during the Renaissance but to a limited amount and never really got the attention they deserved. In 17th century Northern-Europe the principals of passive solar design saw a revival. When they were re-introduced to European society, this time for greenhouses but not for dwellings (figure 51). Those greenhouses were constructed for exotic plants brought back from newly discovered lands. The rich upper class developed an appetite for oranges and other warm climate fruits, therefore creating a need for more greenhouses to be built to grow the exotic foods.31 These greenhouses grew popular in Europe into the 18th century and some refer to that time as the “age of the greenhouse.” The rich upper class began to construct greenhouses that were connected to their dwellings, by doing so, several unexpected benefits were discovered. Aside from being able to grow exotic plants capable of producing fruits and vegetables at home, the design greatly contributed to thermal comfort, especially during the European winter, and it added to the buildings living space. It wasn’t until the 1920’s that passive solar designed dwellings became available for everyone in Europe, starting in Germany in an initiative to build affordable housing for the public, from there the techniques slowly but surely spread over Europe and the Western world. Figure 51
51
America In America, the Native Americans seem to have had a significant understanding of passive solar design concepts as well as the Europeans and Chinese. Semicircular, stepped, south facing villages were constructed in a way so each dwelling in the village had the potential to utilize the sun for thermal comfort (figure 53). Furthermore, the dwellings were constructed of massive materials capable of collecting and storing heat during the day for night time use. Much like the ancient Greeks, the Native-Americans did not have glass in their windows either. Figure 52
Figure 53
Colonial buildings in New England (figure 52) have been found that indicate that the culture of the time had some appreciation and understanding of passive solar principles.32 Saltbox houses had the southern façade of the building two story high and with a lot of windows to catch the sunlight while the northern façade was a onestory wall with a sloping roof to deflect chilly winter winds coming from the north. Aside from those two earlier examples, passive solar never really seemed to get a foothold in American culture until the late 1930’s when numerous architects started exploring the benefits and potential of passive solar principles and it seems to have happened out of necessity after the economic crisis of the early 1920’s. Jacobs House II by architect Frank Lloyd Wright is perhaps the most recognizable passive solar house designed in America during the 19th century and was one Norbert Lechner (2009) Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 32
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of a kind at the time when it was built. The house is also known as “The Solar Hemicycle”, because of its unique half-circle shape and the fact that its designed to capture every ray of sunshine. The houses inner circle, or the southern façade, covered with floor-to-ceiling windows while the northern façade, or the buildings outer circle is earth bermed, covering the ground floor completely, small north facing windows provide daylight on the upper level. Designed with the living area on the ground floor and sleeping quarters on the first floor. Furthermore, the garden inside the circle has been sunk into the ground to prevent shade to reach to the southern façade. Ground floor slab and northern exterior walls made from heavy mass natural materials that have high thermal mass qualities for the direct-gain system that provides thermal comfort to this extraordinary home (figures 54, 55 & 56). Figure 54
Modern Passive Solar When active solar techniques became more reliable, they were thought to be the most efficient method of harnessing solar radiation for energy usage. Later, they discovered that using active solar techniques for space heating was inefficient and33 added significantly to initial building cost. Instead, passive solar principles were re-introduced for space heating because32 they had little or no extra cost conflictions, required less maintenance and were more reliable because they had no
Figure 55
33
David Bergman (2012) Sustainable Design: A critical guide.
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mechanical parts. Therefore, passive solar solutions became the preferred space heating techniques. The usage of passive techniques became popular again when people started to care about the environment and around the same time as oil crises of the 1970’s. Since then the techniques have been increasing in popularity along with all ingenuity regarding our ability to harness solar power. Today it’s popular to see architectural design offices that
advertise
sustainability
and
energy
efficient
design solution as a part of their design goals. Passive techniques are in most cases included for their cost efficiency.
The
popularity
of
passive
solar
varies
between countries. Australia, for example, is at the forefront when it comes to developing a sustainable future in the construction industry with their focus on EnergyPlus
houses
constructions.
and
sustainable,
EnergyPlus
houses
energy
efficient
produce
an
overabundance of energy, enough to sustain themselves and to provide energy to the already existing power grid. The end-goal of EnergyPlus houses is to use the city itself for energy instead of relying on polluting fossil fuelled power plant. Passive solar design fits right into that concept as the best possibility for sustainable and energy efficient space heating.
Figure
54
56
55
References Table of figures FIGURE 1 WIKIPEDIA.COM HTTPS://EN.WIKIPEDIA.ORG/WIKI/EARTH%27S_ORBIT#/MEDIA/FILE: SEASONS1.SVG -22.06.18 4 FIGURE 2 HOMEINTHEEARTH.COMHTTP://WWW.HOMEINTHEEARTH.COM/TECH_NOTES/BASICS-OFEARTHSHELTERING/PASSIVE-SOLAR/ - 22.06.18 5 FIGURE 3 HOMEINTHEEARTH.COMHTTP://WWW.HOMEINTHEEARTH.COM/TECH_NOTES/BASICS-OFEARTHSHELTERING/PASSIVE-SOLAR/ - 22.06.18 5 FIGURE 4 ASTRONOMY21ST.BLOGSPOT.COMHTTP://ASTRONOMY21ST.BLOGSPOT.COM/2010/02/AZIMUTHALTITUDE.HTML - 22.06.18 5 FIGURE 4 ASTRONOMY21ST.BLOGSPOT.COMHTTP://ASTRONOMY21ST.BLOGSPOT.COM/2010/02/AZIMUTHALTITUDE.HTML - 22.06.18 6 FIGURE 5 OCEANOPTICS.COM HTTPS://OCEANOPTICS.COM/FAQ/RESPONSE-COSINE-CORRECTOR/ 22.06.18 6 FIGURE 6 WATERUNIVERSITY.COM HTTPS://WATERUNIVERSITY.TAMU.EDU/PLANTS/SUN-VS-SHADE/ 7 FIGURE 7 SOLARFEEDS.COM - HTTP://WWW.SOLARFEEDS.COM/SOLARSYSTEM-DESIGN-ON-THE-FALL-EQUINOX/ - 22.06.18 7 FIGURE 8 KATHYKIEFER.COM HTTPS://KATHYKIEFERBLOG.COM/TAG/WHAT-IS-THE-GREENHOUSEEFFECT/ - 22.06.18 8 FIGURE 9 QUORA.COM - HTTPS://WWW.QUORA.COM/WHAT-IS-THEBENEFIT-OF-CHINESE-GREENHOUSE-IN-TERMS-OF-TEMPERATUREAND-OTHER-PROPERTIES - 22.06.18 9 FIGURE 10 3M.COM - HTTP://WWW.3M.CO.UK/INTL/UK/3MWORLDLYWISE/CARBON-FOOTPRINT-GREENHOUSE-EFFECT-P1.HTM - 22.06.18 9 56
FIGURE 11 CLEANTECHSOLUTIONS.COM HTTPS://WWW.CLEANTECHLOOPS.COM/PASSIVE-SOLAR-DESIGN/ 22.06.18 12 FIGURE 12 NEWAVENUE.COM HTTPS://APP.NEWAVENUEHOMES.COM/ESTATE/PROJECT/664/# 22.06.18 13 FIGURE 13 TERRI MEYER BOAKE HTTPS://WWW.SLIDESHARE.NET/TBOAKE/SUSTAINABLE-DESIGNPART-THREE-THE-BASIC-PRINCIPLES-OF-PASSIVE-DESIGN - 22.06.18 14 FIGURE 14 MAKEOVER.NL - HTTPS://MAKEOVER.NL/INTERIEUR-DOE-HETZELF/INSPIRATIE-WARM-INTERIEUR - 22.06.18 15 FIGURE 15 VIVIENDASALUDABLE.ES HTTPS://WWW.VIVIENDASALUDABLE.ES/SOSTENIBILIDAD-MEDIOAMBIENTE/VIDA-ARQUITECTURA-SOSTENIBLE/MURO-TROMBE-ENTU-VIVIENDA - 22.06.18 16 FIGURE 16 VIVIENDASALUDABLE.ES HTTPS://WWW.VIVIENDASALUDABLE.ES/SOSTENIBILIDAD-MEDIOAMBIENTE/VIDA-ARQUITECTURA-SOSTENIBLE/MURO-TROMBE-ENTU-VIVIENDA - 22.06.18 16 FIGURE 17 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: SUSTAINABLE DESIGN METHODS FOR ARCHITECTS 18 FIGURE 18 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: 18 SUSTAINABLE DESIGN METHODS FOR ARCHITECTS FIGURE 19 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: 18 SUSTAINABLE DESIGN METHODS FOR ARCHITECTS FIGURE 20 STYLEJUICER.COM - HTTP://STYLEJUICER.COM/WPCONTENT/UPLOADS/2016/03/INTERIORS-CRUSH-PHOTOWERTVOLLFOTOGRAFIE-15.JPG - 22.06.18 19 FIGURE 21 SOLARMIRROR.COM HTTP://WWW.SOLARMIRROR.COM/FOM/FOMSERVE/CACHE/30.HTML - 22.06.18 21 FIGURE 22 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: SUSTAINABLE DESIGN METHODS FOR ARCHITECTS 22 FIGURE 23 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: SUSTAINABLE DESIGN METHODS FOR ARCHITECTS 22 57
FIGURE 24 THE PEI ARK CATALOGUE HTTPS://PEIARK.COM/2015/07/SECTION-OF-BARN-ROCKSTORAGEGREENHOUSE/ - 22.06.18 23 FIGURE 25 THE GREEN GREENHOUSE HTTPS://PEOPLE.UMASS.EDU/CAFFERY/GREENHOUSE/HEATSTORAGE .HTML - 22.06.18 23 FIGURE 26 PINTEREST.COM HTTPS://WWW.PINTEREST.CO.UK/PIN/310115124335597942/ 22.06.18 24 FIGURE 27 APPROPEDIA.ORG HTTP://WWW.APPROPEDIA.ORG/THERMOSIPHON - 22.06.18 25 FIGURE 28 IKLIMNET.COM HTTP://WWW.IKLIMNET.COM/SAVE/PASSIVE_SOLAR_HEATING.HTM L - 22.06.18 25 FIGURE 29 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: SUSTAINABLE DESIGN METHODS FOR ARCHITECTS 25 FIGURE 30 ENVIROARCH.COM - HTTP://ENVIROARCH.COM/DESIGNPHILOSOPHY/THREE-TIER-DESIGN-APPROACH/ - 22.06.18 28 FIGURE 31 NORBERT LECHNER (2009) HEATING, COOLING, LIGHTING: 28 SUSTAINABLE DESIGN METHODS FOR ARCHITECTS FIGURE 32 WORLDARCHITECTURE.COM HTTPS://WORLDARCHITECTURE.ORG/ARCHITECTUREPROJECTS/NVNF/HOUSEDM-BUILDING-PAGE.HTML - 22.06.18 29 FIGURE 33 BEATBUNNY.COM HTTP://WWW.BETABUNNY.COM/PREDATORS/IMAGES/WORLD_TEM PERATURE.GIF - 22.06.18 30 FIGURE 34 RESEARCHGATE.COM HTTPS://WWW.RESEARCHGATE.NET/PUBLICATION/320013467_INTR A_AND_INTER_%27LOCAL_CLIMATE_ZONE%27_VARIABILITY_OF_AIR _TEMPERATURE_AS_OBSERVED_BY_CROWDSOURCED_CITIZEN_WEA THER_STATIONS_IN_BERLIN_GERMANY – 22.06.18 31 FIGURE 35 CONCEPTHOME.COM HTTPS://WWW.CONCEPTHOME.COM/HOUSE-PLANS/HOUSE-PLANCH333/32/ - 22.06.18 32 FIGURE 36 NEWYOURKYIMBY.COM HTTPS://NEWYORKYIMBY.COM/2013/12/INTERVIEW-BKSKS-
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GEORGE-SCHIEFERDECKER-ON-ONEVANDAM.HTML?UTM_SOURCE=YIMBY+NEWS&UTM_CAMPAIGN=2C 38E91E7DYIMBY_NEWS7_20_2013&UTM_MEDIUM=EMAIL&UTM_TERM=0_D7 6C6A6290-2C38E91E7D-88313037 22.06.18 33 FIGURE 37 OAKLANDONLINE.CO.UK HTTP://WWW.OAKLANDONLINE.CO.UK/UPVC-WINDOWSDOORS/ENERGY-EFFICIENT-A-RATED-WINDOWS/ENERGYRATINGS.ASP - 22.06.18 34 FIGURE 38 OAKLANDONLINE.CO.UK HTTP://WWW.OAKLANDONLINE.CO.UK/UPVC-WINDOWSDOORS/ENERGY-EFFICIENT-A-RATED-WINDOWS/ENERGYRATINGS.ASP - 22.06.18 34 FIGURE 39 TUMBLR.COM - HTTP://OLDWORLDGRANGE.TUMBLR.COM/ 22.06.18 35 FIGURE 40 REFINERY29.COM HTTPS://WWW.REFINERY29.COM/2016/03/106802/ABBEYALMASSOV-GLASS-TREEHOUSE#SLIDE – 22.06.18 36 FIGURE 41 PINTEREST.COM 39 WWW.PINTEREST.DK/PIN/421086633889594285/ - 22.06.18 FIGURE 42 CONCEPT HOME - WWW.CONCEPTHOME.COM/HOUSE40 PLANS/SMALL-HOUSE-CH310/32/ 19.06.18 FIGURE 43 AUTODESK.COM HTTP://BLOGS.AUTODESK.COM/INSIGHT/MORE-FUN-WITH41 DYNAMO-FOR-BPA-AUTOMATIC-SHADING-DESIGN/ - 22.06.18 FIGURE 44 ESPACIEL.COM - HTTPS://ESPACIEL.COM/EN/HOME/942 REFLECTEUR-EXTERIEUR.HTML - 22.06.18 FIGURE 45 YKKAP.COM HTTPS://WWW.YKKAP.COM/COMMERCIAL/PRODUCT/SUN43 CONTROL/LUMINANCE/ - 22.06.18 FIGURE 46 TBOAKE.COM - HTTP://TBOAKE.COM/CARBONAIA/STRATEGIES1B.HTML - 22.06.18 43 FIGURE 47 PLATAFORMAARQUITECTURA.CL HTTPS://WWW.PLATAFORMAARQUITECTURA.CL/CL/780499/58VIVIENDAS-SOCIALES-EN-ANTIBES-ATELIER-PIROLLET59
ARCHITECTES/568AF2C1E58ECE62AE0003A9-58-SOCIAL-HOUSING-INANTIBES-ATELIER-PIROLLET-ARCHITECTES-PHOTO - 22.06.18 44 FIGURE 48 PINIMG.COM HTTPS://I.PINIMG.COM/564X/0C/BB/11/0CBB11D24FF82075A9581E 5E956A0239.JPG - 22.06.18 48 FIGURE 49 OUTSTANDINGPLACES.COM HTTP://WWW.OUTSTANDINGPLACES.COM/POST/46007844162/GRE ECE-PARTHENON - 22.06.18 49 FIGURE 50 ART.COM HTTP://WWW.OUTSTANDINGPLACES.COM/POST/46007844162/GREECE-PARTHENON - 22.06.18 50 FIGURE 51 WEHEARTIT.COM HTTPS://WEHEARTIT.COM/ENTRY/81049477 - 22.06.18 FIGURE 52 ALLPOSTERS.COM - HTTPS://WWW.ALLPOSTERS.COM/-
51
SP/RESTORATION-OF-PUEBLO-BONITO-ANCESTRAL-PUEBLOANANASAZI-SITE-IN-CHACO-CANYON-NEW-MEXICO-1250-ADPOSTERS_I9657896_.HTM?UPI=PIK2PH0&PODCONFIGID=8880731&S ORIGID=106522 – 22.06.18 52 FIGURE 53 HUGOHD.COM - HTTP://HUGOHD.COM/EDITOR/ - 22.06.18 52 FIGURE 54 WRIGHTCHAT.SAVEWRIGHT.ORG - HTTP://WRIGHTCHAT.SAVEWRIGHT.ORG/VIEWTOPIC.PHP?T=6334& VIEW=PREVIOUS&SID=2AF23FCA9ED928C393C332EAAF33D874 – 22.06.18 53 53 FIGURE 55 FIGURE 56 WIKIARQITECTURE.COM HTTP://EN.WIKIARQUITECTURA.COM/FILE:JACOBS_23.JPG – 22.06.18 54
60
Table of tables
The necessary information for calculating information presented in tables 1 and - https://www.engineeringtoolbox.com/
the 3.
Information from table 2 - YourHome.gov.au, http://www.yourhome.gov.au/passivedesign/passive-solar-heating, Chris Reardon, Max Mosher, Dick Clarke.
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