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, Germany ]] The term passive house ('''''Passivhaus''''' in s, School s, Kindergarten s and a Supermarket have also been constructed to the standard. Passive design is not the attachment or supplement of architectural design, but an integrated design process with the architectural designJi Yan and Plainiotis Stellios (2006): Design for Sustainability. Beijing: China Architecture and Building Press. ISBN 7-112-08390-7. Although it is mostly applied to new buildings, it has also been used for refurbishments. The first Passivhaus buildings were built in was built at Waldsee , Minnesota , in 2006 Certified US Passive House . THE STANDARD of a Passivhaus (right) show how little heat is escaping compared to a traditional building (left).]] The Passivhaus standard requires that the building is within the following limits Passive House Requirements :
These standards are much higher than houses built to most normal building codes. For comparisons, see The International Comparisons Section below. National partners within the 'consortium for the Promotion of European Passive Houses' europeanpassivehouses(PEP) are thought to have some flexibility to adapt these limits locally. Space heating requirement By achieving the Passivhaus standards, Passivhaus buildings are able to dispense with conventional heating systems. The ability to do this is the underlying Passivhaus objective. However this does not mean that no heating is required, and most Passivhaus buildings do include a system to provide low levels of supplemental space heating. This is normally distributed through the low-volume Heat Recovery Ventilation system that is required to maintain air quality, rather than by a conventional hydronic or high-volume Forced-air heating system, as described in the Space Heating section below. CONSTRUCTION COSTS In Passivhaus buildings, the cost savings from dispensing with the conventional heating system can be used to fund the upgrade of the building envelope and the heat recovery ventilation system. With careful design and increasing competition in the supply of the specifically designed Passivhaus building products, in Germany it is now possible to construct buildings for the same cost as those built to normal German Building Standards , as was done with the Passivhaus apartments at Vauban, Freiburg Cost Efficient Apartment Passive House . Evaluations have indicated that while it is technically possible, the costs of meeting the Passivhaus standard increase significantly when building in northern Scandinavia above 60° Latitude Passive Houses in High Latitudes Passive Houses in Norway . DESIGN AND CONSTRUCTION techniques and technologies.]] Achieving the major decrease in heating energy consumption required by the standard involves a shift in approach to building design and construction. Design is carried out with the aid of the 'Passivhaus Planning Package' (PHPP) Passivhaus Planning Package , and uses specifically designed Computer Simulation s. To achieve the standards, a number of techniques and technologies are used in combination: Passive solar design Following Passive Solar Building Design techniques, where possible buildings are compact in shape to reduce their surface area, with windows oriented towards the south (in the northern hemisphere) to maximize passive solar gain. However, the use of Solar Gain is secondary to minimizing the overall energy requirements. Passive houses can be constructed from dense or lightweight materials, but some internal Thermal Mass is normally incorporated to reduce summer peak temperatures, maintain stable winter temperatures, and prevent possible over-heating in spring or autumn before normal solar shading becomes effective. Superinsulation Passivhaus buildings employ Superinsulation to significantly reduce the heat leakage through the walls, roof and floor compared to conventional buildings. A wide range of Thermal Insulation materials can be used to provide the required high R-values (low U-value s, typically in the 0.10 to 0.15 W/(m&2.K) range). Special attention is given to eliminating Thermal Bridge s. A disadvantage resulting from the thickness of wall insulation required is that, unless the external dimensions of the building can be enlarged to compensate, the internal floor area of the building may be less compared to traditional construction. In Sweden, to achieve passive house standards, the insulation thickness would be 335 mm (0.10 W/(m&2.K)) and the roof 500 mm (U-value 0.066 W/(m&2.K)). Advanced window technology To meet the requirements of the Passivhaus standard, windows are manufactured with exceptionally high R-values (low U-values, typically 0.85 to 0.70 W/(m&2.K) for the entire window including the frame). These normally combine triple-pane Insulated Glazing (with a good solar heat-gain coefficient, Low-emissivity coatings, Argon or Krypton gas fill, and 'warm edge' insulating glass spacers) with air-seals and specially developed thermally-broken window frames. In Central Europe , for unobstructed south-facing Passivhaus windows, the heat gains from the sun are, on average, greater than the heat losses, even in mid-winter. Airtightness The standard requires the building to achieve very high levels of airtightness, much higher than are normally achieved in conventional construction. Air barriers, careful sealing of every construction joint in the building envelope, and sealing of all service penetrations through it are all used to achieve this. Airtightness minimizes the amount of warm (or cool) air that can pass through the structure, enabling the mechanical ventilation system to recover the heat before discharging the air externally. Ventilation Mechanical Heat Recovery Ventilation systems, with a heat recovery rate of over 80% and high-efficiency electronically commutated (ECM) motors, are employed to maintain air quality, and to recover sufficient heat to dispense with a conventional central heating system. Since the building is essentially airtight, the rate of air change can be optimized and carefully controlled at about 0.4 air-changes per hour. All ventilation ducts are insulated and sealed for air tightness. Although not compulsory, Earth Warming Tubes (typically ≈200 mm diameter, ≈40 m long at a depth of ≈1.5 m) are often buried in the soil to act as earth-to-air heat exchangers and pre-heat (or pre-cool) the intake air for the ventilation system. In cold weather the warmed air also prevents Ice formation in the heat recovery system's Heat Exchanger . Space heating In addition to using passive Solar Gain , Passivhaus buildings make extensive use of their intrinsic heat from internal sources – such as waste heat from lighting, White Goods (major appliances) and other electrical devices (but not dedicated heaters) – as well as body heat from the people and animals inside the building. Together with the comprehensive Energy Conservation measures taken, this means that a conventional Central Heating system is not necessary, although they are sometimes installed due to client skepticism. Instead, Passive houses sometimes have a dual purpose 800 to 1,500 Watt heating and/or cooling element integrated with the supply air duct of the ventilation system, for use during the coldest days. It is fundamental to the design that all the heat required can be transported by the normal low air volume required for ventilation. A maximum air temperature of 50 °C (122 °F) is applied, to prevent any possible smell of scorching from dust that escapes the filters in the system. The air-heating element can be heated by a small Heat Pump , by Solar Thermal Energy , or simply by a Natural Gas or Oil Burner . In some cases a micro-heat pump is used to extract additional heat from the exhaust ventilation air, using it to heat either the incoming air or the hot water storage tank. Small wood-burning stoves can also be used to heat the water tank, although care is required to ensure that the room in which stove is located does not overheat. Beyond the recovery of heat by the heat recovery ventilation unit, a well designed Passive house in the European climate should not need any supplemental heat source if the heating load is kept under 10W/m&2 Passive House Estate in Hannover-Kronsberg p72 . Because the heating capacity and the heating energy required by a passive house both are very low, the particular Energy Source selected has fewer financial implications than in a traditional building, although Renewable Energy sources are well suited to such low loads. Lighting and electrical appliances To minimize the total primary energy consumption, low-energy lighting (such as Compact Fluorescent Lamp s), and high-efficiency electrical appliances are normally used. QUALITY OF LIFE By their design, passive houses usually have the following traits:
INTERNATIONAL COMPARISONS
ORIGINS OF THE PASSIVE HOUSE The Passive House standard originated from a conversation in May 1988 between Professors Bo Adamson of . The eventual building of four Row House s (terraced houses) was designed for four private clients by Architect s Professor Bott, Ridder and Westermeyer. After the concept had been validated at Darmstadt, with space heating 90% less than required for a standard new building of the time, the 'Economical Passive Houses Working Group' was created in 1996. This developed the planning package and initiated the production of the novel components that had been used, notably the windows and the high-efficiency ventilation systems. Meanwhile further passive houses were built in Stuttgart (1993), Naumburg, Hesse , Wiesbaden , and Cologne (1997) European Continental Passive Houses . The products developed for the Passivhaus were further commercialised during and following the European Union sponsored CEPHEUS project, which proved the concept in 5 European countries over the winter of 2000-2001. While some techniques and technologies were specifically developed for the standard, others (such as Superinsulation ) were already in existence, and the concepts of Passive Solar Building Design dates back to antiquity. There was also experience from other Low-energy Building standards, notably the German ''Niedrigenergiehaus'' (low-energy house) standard, as well as from buildings constructed to the demanding energy codes of Sweden and Denmark . COMPARISON WITH ZERO ENERGY BUILDINGS A net zero energy building (ZEB) is another term for a related approach to creating buildings that use substantially less energy. A ZEB requires the use of onsite Renewable Energy technologies like PV to offset the building's primary energy use. See Zero Energy Building for more information on ZEB strategies, and on the debate over the appropriate use of active and passive techniques. SEE ALSO
REFERENCES EXTERNAL LINKS Official Passive House organisations
Passive House research
Passive House examples Residential
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Educational
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