A guide to Passive Houses: designs, costs and savings
Passive systems do not use mechanical devices such as fans, blowers, or pumps to distribute solar heat from a collector. Instead, they take advantage of natural heat flow to distribute warmth. An example of a passive system for space heating is a sunspace or solar greenhouse. Passive Solar Heating. Today, we’re going to tell you all about the benefits of using a passive solar heating system in your current home, or a new home currently being designed to help you achieve some amazing long term cost savings and reduce the carbon footprint of your house. This kind of heating system is actually based on an ancient technology that has been around for millennia.
Passive solar heating and coolingsometimes referred to simply as passive solar designis the process of using specific building systems to help regulate internal temperature by using the Sun 's energy ;assive and beneficially in an attempt to improve the energy efficiency.
In these systems, the building itself systtem some element of it takes advantage of the natural energy characteristics of materials when exposed to the Sun. Generally these passive systems are simplistic with few moving parts, thus requiring minimal maintenance. This engineering required to create these systems includes carefully selecting materials for the building envelope - including the building's wallsfloors, roofs, windows and their glazing materials - and determining their proper orientation.
Passive heating and cooling strategically captures or shades against solar radiation. Solar heating and cooling systems take advantage of natural processes such as conductionconvection and radiation to warm or cool a building. Because of this, they require little to no external energy to function and can contribute to the energy efficiency of a home.
When the Sun shines, the solar radiation passjve what is a passive heating system. Wat solar energy is converted into heat and transported by hot air or water into the building. Additionally, the heat gain from the solar insolation can be stored for future use.
Capturing solar radiation in the winter helps to warm up the space, and how to burn a bootable cd with imgburn from solar radiation in the summer cools the space. Hence, the use of insulation and thermal mass is crucial to prevent what is a passive heating system of a space what are the side effects of hyperthyroidism the winter.
Passive heating and cooling systems are used to avoid using air conditioning or a heater. Many of the most advanced techniques for home temperature control use passive methods to accomplish energy efficiency. There are a variety of different technologies that selectively harness how to read faster and recall more shield against the Sun's energy to heat or cool a building without using a what is a passive heating system or air conditioner.
These technologies include operable windows, solar chimneyssolar wallsand trombe walls. These technologies used to regulate internal space temperatures by capturing or venting heat from solar radiation.
Shading technology can also be used strategically to reduce heating. By creating places where shade can be increased or decreased, the amount of solar radiation entering a space is reduced, therefore keeping the room cool without the use of an air conditioner. These technologies can be used for a newly built structure and can also be incorporated into existing structures.
Local climate is always the biggest factor when designing and implementing passive solar heating and cooling systems. Here's an article with a more in depth discussion of architecture in passive solar heating and cooling. Fossil Fuels. Nuclear Fuels. Acid Rain. Climate Change. Climate Feedback. Ocean Acidification. Rising Sea Level. Passive solar heating and cooling.
Passive Heat Kit
Sep 20, · Passive solar heating allows homeowners to collect, absorb, and distribute solar energy right through their windows. By using materials that hold onto heat during the day and disperse it at night, homeowners can keep their houses comfortable 24/7 even in . Oct 03, · Passive heating and cooling in homes is simply a matter of determining where the sun exposure is, and trying to capture and keep as much of that heat as you can in the winter while keeping it out in the summer. This may seem like a tall order, but the seasonal position of the sun conveniently serves this end. Jun 07, · Passive solar water-heating systems can be categorized as either direct or indirect. A direct passive solar water-heating system is the simplest. The crudest form of direct passive solar water heating is to paint a water storage tank black to absorb heat into the water. Such systems were employed in the past at summer campgrounds where.
Passive solar heating is one of several design approaches collectively called passive solar design. When combined properly, these strategies can contribute to the heating, cooling, and daylighting of nearly any building. The types of buildings that benefit from the application of passive solar heating range from barracks to large maintenance facilities. Passive solar heating systems do not have a high initial cost or long-term payback period , both of which are common with many active solar heating systems.
Increased user comfort is another benefit to passive solar heating. If properly designed, passive solar buildings are bright and sunny and in tune with the nuances of climate and nature. As a result, there are fewer fluctuations in temperature, resulting in a higher degree of temperature stability and thermal comfort. By providing a delightful place to live and work, passive solar buildings can contribute to increased satisfaction and user productivity. In addition, passive solar design does not generate greenhouse gases and slows fossil fuel depletion.
There are a few considerations with passive solar design. First, to achieve the highest efficiency, the system needs to have maximum exposure to the sunlight. Second, the intensity of sunlight is intermittent, and the system can overload, which may adversely affect particular electrical appliances like air conditioners and computers. However, with the help of experienced passive solar designer architects and builders, passive solar design costs little more than conventional building design and saves money over the long term.
It is best to incorporate passive solar heating into a building during the initial design. The whole building approach evaluates it in the context of building envelope design particularly for windows , daylighting , and heating and cooling systems. Passive solar heating strategies provide opportunities for daylighting and views to the outside through well-positioned windows.
Window design—and especially glazing choices—is a critical factor for determining the effectiveness of passive solar heating. Passive solar features, such as additional south-facing windows, additional thermal mass, and roof overhangs, can easily pay for themselves.
Overall, passive solar buildings are often less expensive when the lower annual energy and maintenance costs are factored in over the life of the building. This overview is intended to provide specific details for Federal agencies considering passive solar heating technologies as part of a new construction project or major renovation.
Passive solar heating systems make use of the building components to collect, store, and distribute solar heat gains to reduce the demand for space heating.
A passive solar system does not require the use of mechanical equipment because the heat flow is by natural means, such as radiation, convection, and conductance, and the thermal storage is in the structure itself. A passive solar heating system is made up of the following key components, all of which must work together for the design to be successful:. In a passive solar heating system, the aperture collector is a large glass window area through which sunlight enters the building.
The hard, darkened surface of the storage element is known as the absorber. This surface—which could consist of a masonry wall, floor, or partition phase change material , or a water container—sits in the direct path of sunlight. Sunlight then hits the surface and is absorbed as heat. The thermal mass is made up of materials that retain or store the heat produced by sunlight. The difference between the absorber and thermal mass, although they often form the same wall or floor, is that the absorber is an exposed surface, whereas thermal mass is the material below or behind that surface.
Distribution is the method by which solar heat circulates from the collection and storage points to different areas of the building. A strictly passive design will use the three natural heat transfer modes exclusively—conduction, convection, and radiation. In some applications, however, fans, ducts, and blowers may help with the distribution of heat through the building. Elements to help control under- and overheating of a passive solar heating system include roof overhangs , which can be used to shade the aperture area during summer months, electronic sensing devices, such as a differential thermostat that signals a fan to turn on, operable vents and dampers that allow or restrict heat flow, low-emissivity blinds , and awnings.
Passive solar buildings are designed to let the heat into the building during the winter months, and block out the sun during hot summer days. This can be achieved by passive solar design elements such as shading, implementing large south-facing windows, and building materials that absorb and slowly release the sun's heat.
Incorporating shading concepts into your landscape design can help reduce the solar heat gain in the summer and reduce cooling costs. The leaves of deciduous trees or bushes located to the south of the building can help block out sunshine and unneeded heat in the summer.
These trees lose their leaves in the winter, and allow an increase in the solar heat gain during the colder days. Incorporating overhangs, awnings, shutters and trellises into the building design can also provide shade.
A trellis with a climbing vine can shade a home and allow air circulation. Photo by John Krigger, Saturn Resource. Effective thermal mass materials, like concrete, or stone floor slabs, have high specific heat capacities, as well as high density. It is ideally placed within the building where it is exposed to winter sunlight but insulated from heat loss. The material is warmed passively by the sun and releases the thermal energy into the interior during the night.
The most important characteristic of passive solar design is that it is holistic, and relies on the integration of a building's architecture, materials selection, and mechanical systems to reduce heating and cooling loads. It is also important to consider local climate conditions, such as temperature, solar radiation, and wind, when creating climate-responsive, energy conserving structures that can be powered with renewable energy sources.
In climates that are appropriate for passive solar heating, large south-facing windows are used, as they have the most sun exposure in all seasons. Although passive solar heating systems do not require mechanical equipment for operation, fans or blowers may be used to assist the natural flow of thermal energy. The passive systems assisted by mechanical devices are referred to as hybrid heating systems.
Passive solar systems utilize basic concepts incorporated into the architectural design of the building. This typically includes buildings with rectangular floor plans, elongated on an east-west axis, a glazed south-facing wall, a thermal storage media exposed to the solar radiation which penetrates the south-facing glazing, overhangs, or other shading devices , which sufficiently shade the south-facing glazing from the summer sun, and windows on the east and west walls, and preferably none on the north walls.
To achieve a high percentage of passive solar heating, it is necessary to incorporate adequate thermal mass in buildings. Specific guidelines for this include the following:. Sizing of glass areas, insulation values, shading, and mass will depend on climate. Higher solar savings contributions will require greater amounts of glazing and mass.
Be aware that the relationship between glass area and mass is not linear. For example, a doubling of glass area may require a tripling of effective thermal mass. There are two main uses for passive solar heating: skin-load dominated buildings in cold and temperate climates, and internal-load dominated buildings in warm climates. For small, skin-load dominated buildings in cold and temperate climates, passive solar design often involves using solar energy to provide space heating.
For other kinds of structures, such as internal-load dominated buildings in warm climates, responsible passive solar design is more likely to emphasize cooling avoidance using shading devices, high performance glazing, and daylighting.
In a skin-load dominated structure, energy consumption is primarily dictated by the influence of the exterior climate on a building's envelope, or "skin. Internal-load dominated buildings such as educational facilities , offices , or large retail complexes often consume the majority of their energy to provide interior lighting and to provide cooling to counteract the heat given off by people, plug-loads such as computers , fixtures, and other internal sources.
Such buildings can require cooling year-round. Note, however, that less solar radiation enters a well-shaded south window in the summer than a similarly shaded window on the north, east, or west side of the building. Depending on climate, the passive solar design of internal-load dominated buildings might include:.
There are four generic passive solar heating approaches for skin-load dominated buildings: 1 sun-tempered, 2 direct gain, 3 indirect gain, and 4 isolated gain. The four approaches for passive solar heating in skin-load dominated buildings. Sun-tempering is achieved through modest increases in south-facing windows.
In this case, no thermal mass needs to be added to the basic design the "free mass" of gypsum wallboard and furnishings is sufficient to store the additional solar heat. Direct gain is the most basic form of passive solar heating. Sunlight admitted through south-facing glazing in the Northern Hemisphere enters the space to be heated, and is stored in a thermal mass incorporated into the floor or interior walls. Beyond that, problems with glare or fading of fabrics are likely to occur, and it becomes more difficult to provide enough thermal mass for year-round comfort.
An indirect gain passive solar heating system also called a Trombe wall or a thermal storage wall is a south-facing glazed wall, usually built of heavy masonry, but sometimes using containers of water or phase change materials.
Sunlight is absorbed into the wall and it heats up slowly during the day. Then, as it cools gradually during the night, it releases its stored heat over a relatively long period of time indirectly into the space. Isolated gain, or sunspace, passive heating collects the sunlight in an area that can be closed off from the rest of the building. The doors or windows between the sunspace and the building are opened during the day to circulate collected heat, and then closed at night, allowing the temperature in the sunspace to drop.
Small circulating fans may also be used to move heat into adjacent rooms. Now available are exterior concrete walls that are insulated on the outside to protect the concrete from weather.
To exchange heat with the room air, the concrete should be exposed on the inside. Passive solar heating strategies should only be used when appropriate. Passive solar heating works better in smaller buildings where the envelope design controls the energy demand. This means a space that is not already heated by busy people, lights, computers and other internal heat gain. Strategies, such as trombe walls, exist to mitigate unwanted glare and excessive heat gain, but care must be taken when introducing solar heat into workspaces.
Passive solar heating is often used on circulation spaces such as lobbies and atria, hallways, break rooms, and other types of spaces with low internal heat gain that afford occupants the flexibility to move out of the sun. The primary types of buildings that can benefit the most from the application of passive solar heating principles are:.
This approach should be considered for many small buildings in temperate and cold climates. With the help of experienced passive solar designer architects and builders, passive solar design costs little more than conventional building design and saves money over the long term.
However, in areas where experienced solar architects and builders are not available, construction costs can run higher than for conventional buildings, and mistakes can be made in the choice of building materials, especially window glass.
For example, passive solar homes are often built using glass that rejects solar energy. Unfortunately, this is a costly mistake. The right glass choice depends on the climate and on which side of the building east, west, north, or south the glass is installed. During the summer or in consistently warm climates, daylighting could actually increase energy use in a building by adding to its air-conditioning load.
In climates with clear skies during the winter heating season and where alternative heating sources are relatively expensive, passive solar heating will tend to work the best and be the most economical option. A good passive solar site is one that will allow its solar surfaces to face true south with a minimal amount of shading in the solar access zone.
Facing solar surfaces to the south is not enough to ensure their performance; the area to the south must be clear of obstructions that could block the sun from reaching them. In the winter, there should be no significant blockage between 9 a. Obstructions directly to the south of the building need to be located at a distance of at least 1. It is important to remember that the sun is lower in the sky and casts longer shadows in winter.