ТОП 10:

Choose any source of energy and make a short presentation. Try to use additional information.



 

Reading task B

 

Read the text and answer the questions after it.

 

What is a passive house?

 

“Maximising the use of solar energy

and minimising heat loss is our credo.”

Rolph Disch

A passive house is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. The house heats and cools itself, hence “passive”.

Passive solar building design uses the structure's windows, walls, and floors to collect, store, and distribute the sun's heat in winter and reject solar heat in summer. It can also maximize the use of sunlight for interior illumination.

The technology is called passive solar design, or climatic design. Unlike active solar heating systems, it doesn't involve the use of mechanical and electrical devices — such as pumps, fans, or electrical controls — to circulate the solar heat. Buildings thus designed incorporate large south-facing windows and construction materials that absorb and slowly release the sun's heat. The longest walls run from east to west. In most climates, passive solar designs also must block intense summer solar heat. They typically incorporate natural ventilation and roof overhangs to block the sun's strongest rays during that season.

"Day lighting" takes advantage of natural sunlight, through well-placed windows and specialized floor plans, to brighten up a building's interior.

Passive solar design can be used in most parts of the world.

In the United Kingdom, an average new house built to the passive house standard would use 77% less energy for space heating, compared to the Building Regulations.

In Ireland, it is calculated that a typical house built to the passive house standard instead of the 2002 Building Regulations would consume 85% less energy for space heating and cut space-heating related carbon emissions by 94%.

The first passive house buildings were built in Darmstadt, Germany, in 1990, and occupied the following year. In September 1996 the Passive House Institute was founded in Darmstadt to promote and control the standard. More than 6,000 passive house buildings have been constructed in Europe, most of them in Germany and Austria, with others in various countries worldwide. In North America the first passive house was built in Urbana, Illinois in 2003, and the first to be certified was built at Waldsee, Minnesota, in 2006.

In the United States, a house built to the passive house standard results in a building that requires between 75 and 95% less energy for space heating and cooling than current new buildings that meet today's US energy efficiency codes. The passive house in the German Language Village, Waldsee, in Minnesota uses 85% less energy than a normal house of its size.

 

Elements of passive solar design

 

Every passive solar building includes five distinct design elements:

1. An aperture or collector — the large glass area through which sunlight enters the building.

2. An absorber — the dark surface of the storage element that absorbs the solar heat.

3.

Elements of passive solar design, shown in a direct gain application.  
A thermal mass — the material that stores the absorbed heat. This can be masonry materials such as concrete, stone, and brick; or a water tank.

4. A distribution method — the natural tendency of heat to move from warmer materials to cooler ones (through conduction, convection, and radiation) until there is no longer a temperature difference between the two.

5. A control mechanism — to regulate the amount of sunlight entering the aperture. This can be as simple as roof overhang designed to allow more sunlight to enter in the winter, less in the summer.

 

Main features of passive houses design

· the air is fresh and very clean but dry (especially during winter).

· Due to the high resistance to heat flow (high R-value insulation), there are no "outside walls" which are colder than other walls.

· as there are no radiators, there is more space on the rooms' walls.

· inside temperature is homogeneous; it is impossible to have single rooms (e.g. the sleeping rooms) at a different temperature from the rest of the house.

· the temperature changes only very slowly - with ventilation and heating systems switched off, a passive house typically loses less than 0.5 °C per day (in winter), stabilizing at around 15 °C in the central European climate.

· opening windows for a short time only has a very limited effect - after the windows are closed, the air very quickly returns to the "normal" temperature.

 

Peculiarities of passive solar construction

 

Space heating

Passive house 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.

2. Superinsulation

Passive house buildings employ super insulation to significantly reduce the heat transfer through the walls, roof and floor compared to conventional buildings.

Air tightness

Building envelopes under the passive house standard are required to be extremely airtight compared to conventional construction. Air tightness minimizes the amount of warm (or cool) air that can pass through the structure.

Ventilation

Mechanical heat recovery ventilation systems are employed to maintain air quality, and to recover sufficient heat to dispense with a conventional central heating system All ventilation ducts are insulated and sealed against leakage.

5. Typical passive house windows

Windows normally combine triple-pane insulated glazing with air-seals and specially developed thermally-broken window frames.







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