Passive solar buildings aim to maintain interior thermal comfort throughout the sun's daily and annual cycles whilst reducing the requirement for active heating and cooling systems.^[1] Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... HVAC may also stand for High-voltage alternating current HVAC systems use ventilation air ducts installed throughout a building that supply conditioned air to a room through rectangular or round outlet vents, called diffusers; and ducts that remove air from return-air grilles Fire-resistance rated mechanical shaft with HVAC...

Passive solar building design revolves around a set of core physical environmental-and-scientific principles. Specific attention is directed to the site and location of the dwelling, the prevailing climate, design and construction, solar orientation, placement of glazing-and-shading elements, and incorporation of thermal mass. Whilst these considerations may be directed to any building, achieving an ideal solution requires careful integration of these principles. Modern refinements through computer modeling and application of other technology can achieve significant energy savings without necessarily sacrificing functionality or creative aesthetics.^[2][3] Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ...

Passive solar building design is only one part of thermally-efficient building design, which in turn is only one part of sustainable design. Although the terms are often used as synonyms, passive solar design does not include important factors such as ventilation, evaporative cooling, or life cycle analysis, unless these operate solely by the sun without mechanical systems. Sustainable design (also referred to as green design, eco-design, or design for environment) is the art of designing physical objects and the built environment to comply with the principles of economic, social, and ecological sustainability. ... Return inlet (left)Supply outlet (right). ... Evaporative cooling is a system in which latent heat of evaporation is used to carry heat away from an object to cool it. ... In the context of the energy industry, life cycle analysis refers to the holistic approach of including all tangible and perhaps some intangible costs of energy production from the initial project conception to the final step of returning the land to its original or next use state. ...

Passive solar building design is often a foundational element of a cost-effective zero energy building.^[4][5][6] Although a ZEB uses multiple passive solar building design concepts, a ZEB is usually not purely passive, having active mechanical renewable energy generation systems such as: wind turbine, photovoltaics, micro hydro, geothermal, and other emerging alternative energy sources. Similar or related terms: Near zero energy building, Zero energy house, Near zero energy house A zero energy building (ZEB) can be described as structure with a net energy consumption of zero over a typical year. ... This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... Photovoltaic tree in Styria, Austria Photovoltaics, or PV for short, is a solar power technology that uses solar cells or solar photovoltaic arrays to convert light from the sun directly into electricity. ... Micro Hydro is a term used for hydroelectric power installations that typically produce up to 100 kW of power. ... Geothermal may refer to: Geothermal (geology), heat that comes from within the Earth Geothermal desalination, the production of fresh water using heat energy extracted from underground rocks Geothermal heating, a method of heating and cooling a building using underground heat Geothermal power, electricity generated from naturally occurring geological heat sources...

Passive solar building design goals

• During the cool season: Control the admission or storage of 'free' solar thermal energy (heat) while minimizing heat losses through the building envelope.
• During the warm season: Slow heat gain, and exhaust undesired heat by cross-ventilation and convection currents
• During the moderately temperate Spring and Fall seasons: Provide controls that accommodate daily weather variations of sunshine, temperature and humidity.^[1]

Heat distribution between sections of the building may be controlled actively, or passively by taking advantage of the natural flow of heat(e.g. convection flow loops). For example, venting heat from an equator-facing solarium to warm the opposite (cold) side of the building in the winter. Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... Solar thermal energy is a technology for harnessing solar energy for practical applications from solar heating to electrical power generation. ... In regards to printing a thermal transfer printer has a print-head containing many small resistive heating pins that on contact, depending on the type of thermal transfer printer, melt wax-based ink onto ordinary paper or burn dots onto special coated paper. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ...

Solar path fundamentals

Main article: Sun path

The ability to achieve these goals simultaneously is fundamentally dependent on the seasonal variations in the sun's path throughout the day

This occurs as a result of the inclination of the earth's axis of rotation in relation to its orbit. The sun path is unique for any given latitude. Generally the sun will appear to rise in the east and set in the west. For the science fiction novella by William Shunn, see Inclination (novella). ... Two bodies with a slight difference in mass orbiting around a common barycenter. ...

In Northern Hemisphere non-tropical latitudes farther than 23.5 degrees from the equator:

• The sun will reach its highest point toward the South (in the direction of the equator)
• As winter solstice approaches, the angle at which the sun rises and sets progressively moves further toward the South and the daylight hours will become shorter
• The opposite is noted in summer where the sun will rise and set further toward the North and the daylight hours will lengthen^[7]

The converse is observed in the Southern Hemisphere, but the sun rises to the east and sets toward the west everywhere. Noon is the time exactly halfway through the day, written 12:00 in the 24-hour clock and 12:00 noon in the 12-hour clock. ... “Summer solstice” redirects here. ... Azimuth is the horizontal component of a direction (compass direction), measured around the horizon, from the north toward the east (i. ... A typical sunrise, in New Zealand A sunrise through clouds over Oakland, California. ... A composite image showing the terminator dividing night from day, running across Europe and Africa. ...

In equatorial regions at less than 23.5 degrees, the position of the sun at solar noon will oscillate from north to south and back again during the year.^[8] Noon is the time exactly halfway through the day, written 12:00 in the 24-hour clock and 12:00 noon in the 12-hour clock. ...

In regions closer than 23.5 degrees from either north-or-south pole, during summer the sun will trace a complete circle in the sky without setting whilst it will never appear above the horizon six months later, during the height of winter.^[9]

The 47-degree difference in the altitude of the sun at solar noon between winter and summer forms the basis of passive solar design. This information is combined with local climatic data (degree day) heating and cooling requirements to determine at what time of the year solar gain will be beneficial for thermal comfort, and when it should be blocked with shading. By strategic placement of items such as glazing and shading devices, the percent of solar gain entering a building can be controlled throughout the year. Noon is the time exactly halfway through the day, written 12:00 in the 24-hour clock and 12:00 pm in the 12-hour clock. ... A degree day is a measure of heating or cooling. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ...

One passive solar sun path design problem is that the sun is in the same relative position six weeks before, and six weeks after, the solstice, BUT due to "thermal lag" from the thermal mass of the Earth, the temperature and solar gain requirements are quite different before-and-after the summer-and-winter solstice. Movable shutters, shades, shade screen, or window quilts can accommodate day-to-day and hour-to-hour solar gain and insulation requirements. Solar panels are used in passive and active solar hot water systems Passive solar technologies convert sunlight into usable heat, cause air-movement for ventilation or cooling, or store heat for future use, without the assistance of other energy sources. ... Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ...

Careful arrangement of rooms completes the passive solar design. A common recommendation for residential dwellings is to place living areas facing solar noon and sleeping quarters on the opposite side.^[10]. A heliodon is a traditional movable light device used by architects and designers to help model sun path effects. In modern times, 3D computer graphics can visually simulate this data, and calculate performance predictions.^[2] A heliodon (HEE-leo-don) is a device for adjusting the angle between a flat surface and a beam of light to match the angle between a horizontal plane at a specific latitude and the solar beam. ...

Passive solar thermodynamic principles

Main articles: Building insulation and Insulated glazing

• Personal thermal comfort is a function of ambient air temperature, mean radiant temperature, air movement (wind chill, turbulence) and relative humidity (perspiration / evaporation cooling)
• Heat transfer in buildings occurs through convection, conduction, and thermal radiation through roof, walls, floor and windows^[11]
• Convective heat transfer can be beneficial or detrimental. Uncontrolled air infiltration from poor weatherisation/weatherstripping/draught-proofing can contribute up to 40% of heat loss during winter^[12]. Strategic placement of operable windows or vents can enhance convection, cross-ventilation, and summer cooling when the outside air is of a comfortable temperature and relative humidity,^[13] (but unfiltered air intake can bring in undesirable humidity, dust, pollen, and microorganisms). Filtered energy recovery ventilation systems may be useful.
• Natural convection causing rising warm air and falling cooler air can result in an uneven stratification of heat. This may cause uncomfortable variations in temperature in the upper and lower conditioned space, serve as a method of venting hot air, or be designed in as a natural-convection air-flow loop for passive solar heat distribution and temperature equalization.
• Natural human cooling can be facilitated by perspiration / evaporation through natural-or-forced convective air movement, but ceiling fans can disturb the stratified insulating air layers at the top of a room, and accelerate heat transfer from and hot attic, or through near by windows (with turbulence).
• High relative humidity inhibits evaporative cooling.
• The main source of heat transfer is radiant energy, and the primary source is the the sun. Solar radiation occurs predominantly through the roof and windows (but also through walls).
• Thermal radiation moves from a warmer surface to a cooler one. It can move into a window in the day time, and out of the same window at night. Radiation uses photons to transmit electromagnetic waves through a vacuum, or translucent medium. Solar heat gain can be significant even on cold clear days.
• A cool roof, or green roof plus radiant barrier can help prevent your attic from becoming hotter that the peak summer outdoor air temperature.^[14] (See albedo, absorptivity, emissivity, and reflectivity)
• Glazing is particularly difficult to insulate compared to roof and walls (See insulated glazing)
• Windows are a ready and predictable site for thermal radiation.^[15]
• External shading of glazing is more effective at reducing heat gain than internal window coverings.^[15]
• Convective heat transfer through and around window coverings degrade its insulation properties.^[15]
• Western and Eastern sun can provide warmth and lighting, but are vulnerable to overheating in summer if not shaded. Like all glazing they are sites of heat loss on cold night, and heat gain on hot days.
• The non-solar aspect can provide diffused light, but they are sites of undesireable heat transfer summer and winter.
• The low midday sun readily admits light and warmth during the winter, but can be easily shaded with appropriate length overhangs or angled louvres during summer.
• The amount of radiant heat received is related to the location latitude, altitude, cloud cover, and seasonal / hourly angle of incidence. (See Sun path and Lambert's cosine law)
• Thermal energy can be stored in certain building materials and released again when heat gain eases. It stabilizes diurnal (day/night) temperature variations.
• The complex interaction of thermodynamic principles can be counterintuitive for first-time designers. Precise computer modeling can help avoid costly construction experiments.

Common insulation applications inside an apartment building in Mississauga, Ontario, Canada. ... Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ... Mean Radiant Temperature (MRT) is the uniform surface temperature of a black enclosure with which an individual exchanges the same heat by radiation as the actual environment considered. ... Wind chill is the apparent temperature felt on the exposed human (or animal) body due to the combination of air temperature and wind speed. ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... A hygrometer used to measure the humidity of air. ... Perspiration (also called sweating or sometimes transpiration) is the production and evaporation of a fluid, consisting primarily of water as well as a smaller amount of sodium chloride (the main constituent of table salt), that is excreted by the sweat glands in the skin of mammals. ... Vaporization redirects here. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a colder body. ... Convection in the most general terms refers to the movement of currents within fluids (i. ... Conduction has several meanings. ... Radiant heat redirects here. ... This article or section does not cite any references or sources. ... A hygrometer used to measure the humidity of air. ... Stack effect is the ventilation in buildings and chimneys that results from thermal differences between indoor and outside temperature. ... Stratification gooberini went to lousville to dance on a praire and then he went down the hill to hang out with jarry. ... Solar panels are used in passive and active solar hot water systems Passive solar technologies convert sunlight into usable heat, cause air-movement for ventilation or cooling, or store heat for future use, without the assistance of other energy sources. ... Perspiration (also called sweating or sometimes transpiration) is the production and evaporation of a fluid, consisting primarily of water as well as a smaller amount of sodium chloride (the main constituent of table salt), that is excreted by the sweat glands in the skin of mammals. ... Vaporization redirects here. ... In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. ... A hygrometer used to measure the humidity of air. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a colder body. ... Radiant energy is the energy of electromagnetic waves. ... Radiant heat redirects here. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ... The albedo of several types of roofs Cool roofs are an effective alternative to bulk attic insulation under roofs in humid tropical and subtropical climates. ... Re-creation of Viking houses in Labrador Several grass roofs can be seen in the village of Bøur in the Faroe Islands. ... Radiant barriers or reflective barriers work by reducing heat transfer by thermal radiation. ... For other uses, see Albedo (disambiguation). ... In analytical chemistry, the molar absorptivity or extinction coefficient ε of a chemical species at a given wavelength is a measure of how strongly the species absorbs light at that wavelength. ... The emissivity of a material (usually written ) is the ratio of energy radiated by the material to energy radiated by a black body at the same temperature. ... In optics, reflectivity is the reflectance (the ratio of reflected power to incident power, generally expressed in decibels or percentage) at the surface of a material so thick that the reflectance does not change with increasing thickness; , the intrinsic reflectance of the surface, irrespective of other parameters such as the... Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ... Radiant heat redirects here. ... A window covering is material used to cover a window to reduce sunlight, to provide additional weatherproofing, or to ensure privacy. ... This article or section does not cite any references or sources. ... A window covering is material used to cover a window to reduce sunlight, to provide additional weatherproofing, or to ensure privacy. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a colder body. ... This article is about the geographical term. ... Altitude is the elevation of an object from a known level or datum. ... Cloud cover (also known as cloudiness, cloudage or cloud amount) refers to the fraction of the sky obscured by clouds when observed from a particular location. ... Fig. ... Lamberts cosine law says that the total radiant power observed from a Lambertian surface is directly proportional to the cosine of the angle θ between the observers line of sight and the surface normal. ... Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... Diurnal may mean: in biology, a diurnal animal is an animal that is active in the daytime. ... Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ... A counter-intuitive proposition is one that does not seem likely to be true when assessed using intuition or gut feelings. ...

Site specific considerations during design

• Latitude and sun path
• Seasonal variations in solar gain e.g. cooling or heating degree days, solar insolation, humidity
• Diurnal variations in temperature
• Micro-climate details related to breezes, humidity, vegetation and land contour
• Obstructions / Over-shadowing - to solar gain or local cross-winds

This article is about the geographical term. ... Heating degree day (HDD) and cooling degree day (CDD) are quantitative indices demonstrated to reflect demand for energy to heat or cool houses and businesses. ... Not to be confused with insulation. ... The term humidity is usually taken in daily language to refer to relative humidity. ... Diurnal temperature variation is a viticultural term that relates to the variation in temperature that occurs from the highs of the day to the cool of nights. ... Categories: Stub | Ecology ...

Basic passive solar building design elements

• Orienting the building to face the equator (or a few degrees to the East to capture the morning sun)^[16]
• Extending the building dimension along the east/west axis
• Adequately-sizing windows to face the midday sun in the winter, and be shaded in the summer.
• Minimising windows on other sides, especially western windows^[15]
• Erecting correctly-sized, latitude-specific overhangs, or shading elements (shrubbery, trees, trellises, fences, shutters, etc.)^[17]
• Using the appropriate amount and type of insulation including radiant barriers and bulk insulation to minimise seasonal excessive heat gain or loss
• Using thermal mass to store excess solar energy during the winter day (which is then re-radiated during the night)^[18]

The precise amount of equator-facing glass and thermal mass should be based on careful consideration of latitude, altitude, climatic conditions, and heating/cooling degree day requirements. Common insulation applications inside an apartment building in Mississauga, Ontario, Canada. ... Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... A degree day is a measure of heating or cooling. ...

Factors that that can degrade thermal performance:

• Deviation from ideal orientation and north/south/east/west aspect ratio
• Excessive glass area ('over-glazing') resulting in overheating (also resulting in glare and fading of soft furnishings) and heat loss when ambient air temperatures fall
• Installing glazing where solar gain during the day and thermal losses during the night cannot be controlled easily e.g. West-facing, angled glazing, skylights ^[19]
• Thermal losses through non-insulated or unprotected glazing
• Lack of adequate shading during seasonal periods of high solar gain (especially on the West wall)
• Incorrect application of thermal mass to modulate daily temperature variations
• Open staircases leading to unequal distribution of warm air between upper and lower floors as warm air rises
• High building surface area to volume - Too many corners
• Inadequate weatherization leading to high air infiltration
• Lack of, or incorrectly-installed, radiant barriers during the hot season. (See also cool roof and green roof)
• Insulation materials that are not matched to the main mode of heat transfer (e.g. undesirable convective/conductive/radiant heat transfer)

Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... Weatherization (American English) or weatherproofing (British English) is the practice of protecting a building and its interior from the elements, particularly from sunlight, precipitation, and wind, and of modifying a building to reduce energy consumption and optimize energy efficiency. ... Radiant barriers or reflective barriers work by reducing heat transfer by thermal radiation. ... The albedo of several types of roofs Cool roofs are an effective alternative to bulk attic insulation under roofs in humid tropical and subtropical climates. ... Re-creation of Viking houses in Labrador Several grass roofs can be seen in the village of Bøur in the Faroe Islands. ... Common insulation applications inside an apartment building in Mississauga, Ontario, Canada. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a colder body. ...

Key passive solar building design concepts

There are four primary passive solar energy configurations:^[20]

• direct solar gain
• indirect solar gain
• isolated solar gain
• passive cooling

Solar gain (also known as solar heat gain or passive solar gain) refers to the increase in temperature in a space, object or structure that results from solar radiation. ... Passive cooling refers to technologies or design features used to cool houses naturally, such as those technologies discussed in the Passive House project. ...

Direct solar gain

Elements of passive solar design, shown in a direct gain application

Direct gain attempts to control the amount of direct solar radiation reaching the living space. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Solar irradiance spectrum at top of atmosphere. ...

The cost effectiveness of these configurations are currently being investigated in great detail and are demonstrating promising results.^[21]

Indirect solar gain

Indirect gain attempts to control solar radiation reaching an area adjacent but not part of the living space. Heat enters the building through windows and is captured and stored in thermal mass (e.g water tank, masonry wall) and slowly transmitted indirectly to the building through conduction and convection. Efficiency can suffer from slow response (thermal lag) and heat losses at night. Other issues include the cost of insulated glazing and developing effective systems to redistribute heat throughout the living area. Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... Heat flow along perfectly insulated wire Conduction is the transfer of heat or electric current from one substance to another by direct contact. ... Convection in the most general terms refers to the movement of currents within fluids (i. ... Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ...

Examples:

• Trombe walls
• Water walls
• Roof ponds

Passive solar design using an unvented trombe wall and summer shading A Trombe wall is a sun-facing wall built from material that can act as a thermal mass (such as stone, concrete, adobe or water tanks), combined with an air space, insulated glazing and vents to form a large...

Isolated solar gain

Isolated gain involves utilizing solar energy to passively move heat from or to the living space using a fluid, such as water or air by natural convection or forced convection. Heat gain can occur through a sunspace, solarium or solar closet. These areas may also be employed usefully as a greenhouse or drying cabinet. An equator-side sun room may have its exterior windows higher than the windows between the sun room and the interior living space, to allow the low winter sun to penetrate to the cold side of adjacent rooms. Glass placement and overhangs prevent solar gain during the summer. Earth cooling tubes or other passive cooling techniques can keep a solarium cool in the summer. Convection in the most general terms refers to the movement of currents within fluids (i. ... The word solarium (pl -lariums or -laria) is Latin and means terrace or flat housetop from the Latin word sol meaning sun. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Passive cooling refers to technologies or design features used to cool houses naturally, such as those technologies discussed in the Passive House project. ...

Measures should be taken to reduce heat loss at night e.g window coverings or movable window insulation

Examples:

• Thermosiphon
• Barra system
• Double envelope house
• Thermal buffer zone^[22]
• Solar space heating system
• Solar chimney

Thermosiphon (alternatively spelled thermosyphon) refers to a method of heat exchange through a phase change heat pump that depends on gravity. ... The Barra system, developed by Horazio Barra in Italy, is a passive solar building technology. ... Solar heating is a style of building construction which uses the energy of sunshine to heat a structure. ... It has been suggested that this article or section be merged with Solar Tower. ...

Other considerations

Insulation

Main article: Building insulation

Thermal insulation or superinsulation (type, placement and amount) assists in significantly reduce unwanted heat transfer.^[23] Common insulation applications inside an apartment building in Mississauga, Ontario, Canada. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... Superinsulation is an approach to building design, construction and retrofitting. ...

Special glazing systems and window coverings

Main articles: Insulated glazing and Window covering

The effectiveness of direct solar gain systems is significantly enhanced by insulative (e.g. double glazing), spectrally-selective glazing (low-e), or movable window insulation (window quilts, bifold interior insulation shutters, shades, etc.).^[24]. Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ... A window covering is material used to cover a window to reduce sunlight, to provide additional weatherproofing, or to ensure privacy. ... Solar gain (also known as solar heat gain or passive solar gain) refers to the increase in temperature in a space, object or structure that results from solar radiation. ... Insulated glazing is a piece of glazing consisting of two or more layers of glazing separated by a spacer along the edge and sealed to create a dead air space between the layers. ... Low-emittance (Low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. ...

Generally, Equator-facing windows should not employ glazing coatings that inhibit solar gain.

There is extensive use of super-insulated windows in the German Passive House standard. Selection of different spectrally-selective window coating depends on the ratio of heating versus cooling degree days for the design location. One of the original Passive Houses at Darmstadt, Germany One of the original Passive Houses at Darmstadt The term passive house (Passivhaus in German) refers to the rigorous, voluntary, Passivhaus standard for energy use in buildings. ... A degree day is a measure of heating or cooling. ...

Glazing selection

Equator-facing glass

The requirement for vertical equator-facing glass is different than for the other three sides of a building. Reflective window coatings and multiple panes of glass can reduce useful solar gain. However, direct-gain systems are more dependent on double or triple glazing to reduce heat loss. Indirect-gain and isolated-gain configurations may still be able to function effectively with only single-pane glazing. Nevertheless, the optimal cost-effective solution is both location and system dependent. Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ... Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ...

Roof-angle glass / Skylights

Sloping roof-angled glass is difficult to shade and insulate without sophisticated movable systems. In hot climates with significant degree day cooling requirements, it can create a summer solar furnace (from the ancient Greek / Roman term "heliocaminus"^[25]). A degree day is a measure of heating or cooling. ... solar oven A solar oven or solar furnace is a way of harnessing the suns power to cook food. ...

Roof-angled glass or skylights are not optimally placed to receive low-angled winter sun. At the same time, they are the site of heat loss during winter from the buoyant warm air that rises. As a result, they will increase heating and cooling energy requirements, which exceeds the benefit of daylight energy consumption reduction compared to more energy-efficient lighting systems such as light tubes. The word skylight, when used alone, has several possible meanings in the English language. ... Stack effect is the ventilation in buildings and chimneys that results from thermal differences between indoor and outside temperature. ... Light tubes or light pipes are used for transporting or distributing natural or artificial light. ...

Transparent glass and plastic have little structural strength. Vertically, they bear their own weight because only the thickness is subject to gravity. As the angle tilts from vertical, an increased area (the sloped cross-section) must resist gravity. Glass is brittle - It does not flex much before breaking - To counteract this, you must increase thickness, or structural supports - Both increase overall cost, and reduce solar gain potential. Sloped glazing is exposed to the weather, leaks, hail, ice-and-snow load, wind, and material failure. Excess solar gain, harsh lighting, and undesirable heat transfer thru sloped glass are difficult to control. “Therefore, vertical glazing is the overall best option for sunspaces.”^[26]

Angle of incident radiation

The amount of solar gain transmitted through glass is also affected by the angle of the incident solar radiation. Sunlight striking glass within 20 degrees of perpendicular is mostly transmitted through the glass, whereas sunlight at more than 35 degrees from perpendicular is mostly reflected^[27] Solar irradiance spectrum at top of atmosphere. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... Fig. ... The reflection of sunlight on water Reflection is the abrupt change in direction of a wave front at an interface between two dissimilar media so that the wave front returns into the medium from which it originated. ...

All of these factors can be modeled more precisely with a photographic light meter and a heliodon or optical bench, which can quantify the ratio of reflectivity to transmissivity, based on angle of incidence. A light meter is a device used to measure the amount of light. ... A heliodon (HEE-leo-don) is a device for adjusting the angle between a flat surface and a beam of light to match the angle between a horizontal plane at a specific latitude and the solar beam. ... In optics, reflectivity is the reflectance (the ratio of reflected power to incident power, generally expressed in decibels or percentage) at the surface of a material so thick that the reflectance does not change with increasing thickness; , the intrinsic reflectance of the surface, irrespective of other parameters such as the... Look up Transmission in Wiktionary, the free dictionary. ... Fig. ...

Alternatively, passive solar computer software can determine the impact of sun path, and cooling-and-heating degree days on energy performance. Regional climatic conditions are often available from local weather services. Solar panels are used in passive and active solar hot water systems Passive solar technologies convert sunlight into usable heat, cause air-movement for ventilation or cooling, or store heat for future use, without the assistance of other energy sources. ... A degree day is a measure of heating or cooling. ...

Operable shading and insulation devices

A design with too much equator-facing glass can result in excessive winter, spring, or fall day heating, uncomfortably-bright living spaces at certain times of the year, and excessive heat transfer on winter nights and summer days.

Although the sun is at the same altitude 6-weeks before and after the solstice, the heating and cooling requirements before and after the solstice are significantly different. Heat storage on the Earth's surface causes "thermal lag." Variable cloud cover influences solar gain potential. This means that latitude-specific fixed window overhangs, while important, are not a complete seasonal solar gain control solution.

Control mechanisms (such as manual-or-motorized interior insulated drapes, shutters, exterior roll-down shade screens, or retractable awnings) can compensate for differences caused by thermal lag or cloud cover, and help control daily / hourly solar gain requirement variations. Home automation systems that monitor temperature, sunlight, time of day, and room occupancy can precisely control motorized window-shading-and-insulation devices. Light control computerized system Home automation (also called domotics) is a field within building automation, specializing in the specific automation requirements of private homes and in the application of automation techniques for the comfort and security of its residents. ...

Exterior finishes

Materials and colors can be chosen to reflect or absorb solar thermal energy. See "Cool Colors" by Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory The term reflection (also spelt reflexion) can refer to several different concepts: In mathematics, reflection is the transformation of a space. ... Absorption has a number of meanings: In physics absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... Solar thermal energy is a technology for harnessing solar energy for practical applications from solar heating to electrical power generation. ...

Landscaping

Energy-efficient landscaping materials, including the use of trees, plants, hedges, or a trellis (agriculture), can be used to selectively create summer shading (particularly in the case of deciduous plants that give up their leaves in the winter), and also to create winter wind chill shelter. Xeriscaping is used to reduce or eliminate the need for energy-and-water-intensive irrigation. Energy-efficient landscaping is a type of landscaping designed for the purpose of conserving energy. ... It has been suggested that this article or section be merged with Tree (disambiguation). ... For other uses, see Plant (disambiguation). ... The word hedge may be used to refer to an artificial boundary, erected to contain or protect: A hedge or hedgerow in agriculture and in gardening is a lineal barrier or boundary made from growing plants planted and trained in such a way that their limbs intertwine. ... This article does not cite any references or sources. ... For other uses, see Deciduous (disambiguation). ... Wind chill is the apparent temperature felt on the exposed human (or animal) body due to the combination of air temperature and wind speed. ... Xeriscape symbol Xeriscaping refers to landscaping in ways that do not require supplemental irrigation. ... Irrigation is the artificial application of water to the soil usually for assisting in growing crops. ...

Other passive solar principles

Passive solar lighting

Main article: Passive solar lighting

Passive solar lighting techniques attempt to take advantage of natural illumination and reduce reliance on artificial lighting systems.

This can be achieved by careful building design and placement of window sections. Other creative solutions involve the use of reflecting surfaces to admit daylight into the interior of a building such as a solar light tube, or light shelf. Window sections should be adequately sized without resulting in over-illumination.^[28] Light tubes or light pipes are used for transporting or distributing natural or artificial light. ... This cosmetics store has lighting levels over twice recommended levels and sufficient to trigger headaches and other health effects Over-illumination is the presence of lighting intensity (illuminance) beyond that required for a specified activity. ...

Another major issue for many window systems is that they can be potentially vulnerable sites of excessive thermal gain or heat loss. Whilst high mounted clerestory window and traditional skylights can introduce daylight in poorly-orientated sections of a building, unwanted heat transfer may be hard to control. ^[29][30] Thus, energy that is saved by reducing artificial lighting is often more than offset by the energy required for operating HVAC systems to maintain thermal comfort. For other uses, see Window (disambiguation). ... Malmesbury Abbey, Wiltshire, England. ... The word skylight, when used alone, has several possible meanings in the English language. ... HVAC may also stand for High-voltage alternating current HVAC systems use ventilation air ducts installed throughout a building that supply conditioned air to a room through rectangular or round outlet vents, called diffusers; and ducts that remove air from return-air grilles Fire-resistance rated mechanical shaft with HVAC... Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. ...

Various methods can be employed to address this including but not limited to window coverings, insulated glazing and novel materials such as aerogel semi-transparent insulation, optical fiber embedded in walls or roof, or hybrid solar lighting at Oak Ridge National Laboratory. A window covering is material used to cover a window to reduce sunlight, to provide additional weatherproofing, or to ensure privacy. ... Insulated Glazing Unit or Insulating Glass Unit (commonly referred to as IGU) is described as two or more lites of glass spaced apart and hermetically sealed to form a single glazed unit with an air space between each lite. ... A 2. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ...

Passive solar water heating

Main article: Solar hot water

There are many ways to use solar thermal energy to heat water for domestic use. Different active-and-passive solar hot water technologies have different location-specific economic cost benefit analysis implications. Solar hot water refers to water heated by solar energy. ... Solar thermal energy is a technology for harnessing solar energy for practical applications from solar heating to electrical power generation. ... Solar hot water refers to water heated by solar energy. ... Cost-benefit analysis is the process of weighing the total expected costs vs. ...

Fundamental passive solar hot water heating involves no pumps or anything electrical. It is very cost effective in climates that do not have lengthy sub-freezing, or very-cloudy, weather conditions. Other active solar water heating technologies, etc. may be more appropriate for some locations.

Design tools

Traditionally a heliodon was used to simulate the altitude and azimuth of the sun shining on a model building at any time of any day of the year.[1] In modern times, computer programs can model this phenomenon and integrate local climate data (including site impacts such as overshadowing and physical obstructions) to predict the solar gain potential for a particular building design over the course of a year. This provides the designer the ability to evaluate design elements and orientation prior to building works commencing. Energy performance optimization normally requires an iterative-refinement design-and-evaluate process. A heliodon (HEE-leo-don) is a device for adjusting the angle between a flat surface and a beam of light to match the angle between a horizontal plane at a specific latitude and the solar beam. ... Shadows on pavement A shadow is a region of darkness where light is blocked. ...

Levels of application

Pragmatic

Many detached suburban houses can achieve reductions in heating expense without obvious changes to their appearance, comfort or usability [2]. This is done using good siting and window positioning, small amounts of thermal mass, with good-but-conventional insulation, weatherization, and an occasional supplementary heat source, such as a central radiator connected to a (solar) water heater. Sunrays may fall on a wall during the daytime and raise the temperature of its thermal mass. This will then radiate heat into the building in the evening. This can be a problem in the summer, especially on western walls in areas with high degree day cooling requirements. External shading, or a radiant barrier plus air gap, may be used to reduce undesireable summer solar gain. Thermal mass, in the most general sense, is any mass that absorbs and holds heat. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ...

Annualised

An extension of the "passive solar" approach to diurnal solar capture and storage ("short-cycle passive solar"). Other experimental designs attempt to capture warm-season solar heat, convey it to a seasonal thermal store for use months later during the cool or cold season ("annualised passive solar.") Increased storage is achieved by employing large amounts of thermal mass or earth coupling. Anecdotal reports suggest they can be effective but no formal study has been conducted to demonstrate their superiority. A seasonal thermal store (also known as a seasonal heat store or inter-seasonal thermal store) is a store designed to retain heat deposited during the hot summer months for use during colder winter weather. ...

Examples:

• Passive Annual Heat Storage (PAHS) - by John Hait
• Annualized Geothermal Solar (AGS) heating - by Don Stephen
• Earthed-roof

Earth covered farm houses in Keldur, Iceland. ...

Minimum machinery

A "purely passive" solar-heated house would have no mechanical furnace unit, relying instead on energy captured from sunshine, only supplemented by "incidental" heat energy given off by lights, computers, and other task-specific appliances (such as those for cooking, entertainment, etc.), showering, people and pets. The use of natural convection air currents (rather than mechanical devices such as fans) to circulate air is related, though not strictly solar design.

Passive solar building design sometimes uses limited electrical and mechanical controls to operate dampers, insulating shutters, shades, awnings, or reflectors. Some systems enlist small fans or solar-heated chimneys to improve convective air-flow. A reasonable way to analyse these systems is by measuring their coefficient of performance. A heat pump might use 1 J for every 4 J it delivers giving a COP of 4. A system that only uses a 30 W fan to more-evenly distribute 10 kW of solar heat through an entire house would have a COP of 300. The coefficient of performance, or COP (sometimes CP), of a heat pump is the ratio of the output heat to the supplied work or where Q is the useful heat supplied by the condenser and W is the work consumed by the compressor. ...

See also

Energy Portal

Sustainable development Portal

• Daylighting
• Solar energy
• Active solar
• Passive solar
• Passive solar lighting
• Passive cooling
• Renewable heat
• Architecture
• Architectural engineering

Passive solar design concepts Image File history File links Portal. ... Image File history File links Sustainable_development. ... Daylighting is the practice of placing windows, or other transparent media, and reflective surfaces so that, during the day, natural light provides effective internal illumination. ... Ultraviolet image of the Sun. ... Active solar is a term which refers to the use of solar energy to actively convert the energy in sunlight into other forms. ... Solar panels are used in passive and active solar hot water systems Passive solar technologies convert sunlight into usable heat, cause air-movement for ventilation or cooling, or store heat for future use, without the assistance of other energy sources. ... Passive cooling refers to technologies or design features used to cool houses naturally, such as those technologies discussed in the Passive House project. ... // Renewable heat is an application of renewable energy, namely the generation of heat from renewable sources. ... This article is about building architecture. ... An architectural engineer applies the skills of many engineering disciplines to the design, construction, operation, maintenance, and renovation of buildings while paying attention to their impacts on the surrounding environment. ...

• Trombe wall
• Barra system
• Passive House
• Earth cooling tubes
• Windcatcher
• Annualized geothermal solar
• Earth sheltering
• Passive solar design history

Energy Efficiency in buildings Passive solar design using an unvented trombe wall and summer shading A Trombe wall is a sun-facing wall built from material that can act as a thermal mass (such as stone, concrete, adobe or water tanks), combined with an air space, insulated glazing and vents to form a large... The Barra system, developed by Horazio Barra in Italy, is a passive solar building technology. ... One of the original Passive Houses at Darmstadt, Germany One of the original Passive Houses at Darmstadt The term passive house (Passivhaus in German) refers to the rigorous, voluntary, Passivhaus standard for energy use in buildings. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A windcatcher (Badgir; بادگیر) is a traditional Persian architectural device used for many centuries to create natural ventilation in buildings. ... Earth covered farm houses in Keldur, Iceland. ...

• Low energy building
• Zero energy building
• Energy plus house

Energy Rating systems This thermogram compares a traditional building (left) to one built to the German passive house standard (right) Generically, a low-energy house is any type of house that uses less energy than a regular house. ... Similar or related terms: Near zero energy building, Zero energy house, Near zero energy house A zero energy building (ZEB) can be described as structure with a net energy consumption of zero over a typical year. ... An energy-plus-house is producing its own energy, or even more than is being used within its own walls. ...

• House Energy Rating (Aust.)
• Home energy rating
• EnerGuide for Houses (Canada)
• EnerGuide for New Houses (Canada)

Solar-designers A House Energy Rating is an index of energy efficency for residential homes in Australia. ... Energuide for houses is a Canadian program developed by the Office of Energy Efficency of Natural Resources Canada (NRCan). ... EnerGuide for New Houses is a Canadian program developed by the Office of Energy Efficiency of Natural Resources Canada (NRCan). ...

• History of passive solar building design
• Category:Solar building designers
• List of pioneering solar buildings
• Steve Baer
• J. Baldwin
• Tom Bender
• Lee Porter Butler
• Peter Calthorpe
• Buckminster Fuller
• Larry Hartweg - DOE/ORNL Zero Energy Design[3]
• William McDonough
• William Shurcliff
• Felix Trombe
• Sim Van der Ryn
• James Wines
• Ken Yeang

The following buildings have been recognised as being of international significance in pioneering the use of modern engineered solar building design: MIT Solar House #1, Massachusetts, USA (HC Hottel, 1939) [1] [1] Boulder House, Colorado, USA (G Löf, 1945)[1] MIT Solar House #2, USA, (HC Hottel, 1947)[1... Steve Baer (1938- ) is an American inventor and solar and residential designer. ... James Tennant Baldwin (whose books and articles have been published under the names J. Baldwin, Jay Baldwin, and James T. Baldwin) is an American industrial designer and writer born in 1934. ... Tom Bender began to make his mark in the early 1970s as an architect, author, and strategic planner. ... Peter Calthorpe has been named one of twenty five innovators on the cutting edge by Newsweek magazine for his work redefining the models of urban and suburban growth in America. ... Richard Buckminster “Bucky” Fuller (July 12, 1895 – July 1, 1983)[1] was an American visionary, designer, architect, poet, author, and inventor. ... William A. McDonough (1951, Tokyo, Japan - ) is an American architect whose career is focused on designing environmentally sustainable buildings and transforming industrial manufacturing processes, with the twin goals of eliminating pollution and increasing the profits of his clients. ... Felix Trombe (b. ... Sim Van der Ryn is acknowledged as a leader in sustainable architecture. ... James Wines (1932- ) is an American architect associated with environmental design. ... Dr. Ken Yeang (Chinese: 杨经文/楊經文; pinyin: Yáng Jīngwén) is a prolific Malaysian architect and writer best known for developing environmental design solutions for high-rise buildings in the tropics. ...

References

2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 14th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 14th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 14th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 357th day of the year (358th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 357th day of the year (358th in leap years) in the Gregorian calendar. ...

External links

• Canadian Solar Buildings Research Network
• www.greenbuilder.com - Passive Solar Design
• www.eere.energy.gov - US Department of Energy (DOE) Guidelines
• www.greenhouse.gov.au - Australian Dept of Climate Change
• www.ornl.gov - Oak Ridge National Laboratory (ORNL) Building Technology
• www.FSEC.UCF.edu - Florida Solar Energy Center
• www.ZeroEnergyDesign.com - 28 Years of Passive Solar Building Design
• Residential Green Building Checklist
• Commercial Green Building Checklist
• Passive Solar Design Guidelines
• http://www.solaroof.org/wiki
• Calculation of insolation (houses, garden, roof, apartment...)
• www.PassiveSolarEnergy.info - Passive Solar Energy Technology Overview
• www.gaisma.com- Sun path calculator for selected cites
• http://sunposition.info/sunposition/spc/locations.php - Sun path by location and date