Energy-saving house. Passive house: design, construction and features

The passive house is a standard of energy efficiency in construction, which allows economically and environmentally friendly, causing minimum harm to the environment, maintaining a comfortable stay. The consumption of heat energy is so small that there is no need to install a separate heating system, or its power and dimensions are small.

Energy Efficiency Standard

The energy consumption for the heating needs of such a house does not exceed 15 kilowatt-hours per unit area per year. The energy consumption for heating, hot water supply and electricity supply of an energy efficient home does not exceed 120 kWh per unit area.

If we compare the energy consumption figures for heating in Germany, which are regulated by the 2002 thermal protection and energy efficiency decrees (WSchVO and EnEV 2002), there is a direct tendency to reduce it for the needs of heating the buildings. A recent EnEV regulation regulating thermal protection in Germany established the norm of annual energy consumption for heating new and sanitized houses from 30 to 70 kilowatt-hours per unit area.

For comparison, in the Russian Federation, the norm of annual energy consumption for heating for Moscow is from 95 to 195 kilowatt-hours per unit area. The actual flow rate exceeds these norms many times.

The advantage of energy-saving houses

Ecohouse has the following advantages:

• Comfort. It provides a constantly maintaining pleasant microclimate, clean and fresh air special engineering system. The passive house at the same time acquires a balance of room temperatures.
• Energy saving. If we compare an ordinary building and a passive house, the latter differs by more than a tenfold reduction in heat consumption for heating needs.
• Health benefits. When the house is passive, throughout the year all living quarters are constantly supplied with fresh air, there are no drafts, high humidity and there is no mold.
• Economical. If the house is passive, the costs of operating its energy supply remain at a low level even with an increase in the cost of energy.
• Care for the environment. When the house is passive, the use of energy-efficient technologies increases the level of environmental protection.

Energy balance

One of the characteristics of an energy efficient house is the energy balance between ventilation or transmission heat loss and its intake with solar energy, internal heat sources and heating. For balance, such components as optimal heat insulation of the heated volume, compactness of the building, passive use of heat input from solar radiation by orienting most windows (up to 2/5 of the facade area) to the south with an allowable deviation of 30 ° and due to the absence of shading are extremely important. It would also be superfluous to use household appliances with a high level of energy efficiency. It is also proposed to heat water using a heat pump or solar collector, passive air heating by a ground heat exchanger. In fact, the ideal passive house is a thermos house without heating.

Passive house: technologies

How is this result achieved? The standard of the passive house assumes work in five directions:

• Thermal insulation. The insulation of external areas, especially angular, butt and transition junctions and intersections, must be such that the heat transfer coefficient is less than 0.15 W / m ² · K.
• Absence of thermal bridges. It is desirable to avoid inclusions that conduct heat. A special program for calculating the temperature field will allow to identify and correctly analyze the unfavorable places of the fencing structures with subsequent optimization.
• Certified for passive eco-house effective windows. Double low-emission double-glazed windows, filled with inert gas, are optimal for such houses. Qualified installation of window constructions.
• Mechanical ventilation with heat recovery (at least 75%) and a sealed inner shell. Identification and elimination of leakage points is provided by conducting automated tests on the air permeability of buildings. Comfortable ventilation, user-controlled. Installation of ground heat exchanger.

Becoming in Russia

In Europe, the building standard of the passive house is applied massively, and in the Russian Federation the design and construction of energy-efficient buildings is only at the stage of formation.

There are no houses that meet the requirements of the energy efficiency standard, but there are already buildings close to this standard. They embody the principles, elements, methods of calculating an energy-efficient home.

Also, with reference to the Russian Federation, a classification of structures for energy efficiency has been created:

• Passive house - the heating consumes less than 15, the total energy consumption per year is not more than 120 kilowatt hours per unit area;
• House with ultra-low consumption - the annual energy consumption for heating needs is 16-35, and the total energy consumption per year is less than 180 kWh per unit area;
• House with a low energy consumption - a building with an annual energy consumption for heating needs - 36-50, and the total annual energy consumption - less than 260 kilowatt-hours per unit area.

History of development

The middle of the 90s of the twentieth century was marked by the founding in Darmstadt, Germany, of the "Passive House" partnership. Architects Westermayer and Bott-Ridder under the direction of Wolfgang Feist designed a four-apartment house, the prototype of which was all subsequent energy-saving houses. The passive house was built in 1991 with the participation of the government of Hesse. The annual consumption of the building for heating needs is less than 1 liter of fuel per unit area.

Design Features

The design of the passive house was completed with the following design solutions.

External walls made of silicate brick with a thickness of 175 mm are insulated with a layer of polystyrene with a thickness of 275 mm, inside are finished with gypsum plaster of 15 mm thickness and three-layer wallpaper, followed by painting.

The roof is covered with humus, filtering layer, particle board 50 mm thick, reinforced with wooden beams, insulated with polyethylene film, insulated with a layer of mineral wool with the thickness of 445 mm, finished with plasterboard and three-layer wallpaper, followed by painting.

Overlap of the basement, 160 mm of reinforced concrete, insulated with 250 mm of polystyrene plates, 40 mm of soundproofing, 50 mm of cement screed and up to 15 mm of parquet.

Windows with three glasses, bilateral low-emission coating, krypton-filled chambers. Wooden frames with polyurethane foam insulation.

The heat recovery is realized by a counter-current heat exchanger in the basement of the house. For the first time, DC motors with electronic switching were used.

Hot water supply is provided by flat vacuum collectors with an area of 5.3 square meters. Meter (66% of the domestic hot water demand) and a compact wall-mounted condensing boiler with natural gas. The pipelines of the DHW system are laid in a heat-insulating layer and well insulated.

Control measurements

Upon completion of the construction and delivery of the building, control measurements of air flow, pressure test, 24-hour temperature and energy consumption measurements were made. They confirmed the achievement of the goal.

The annual consumption of heat for heating in 1991-1992 was 19.8 kilowatt-hours per unit area, accounting for 8 percent of the consumption of apartments in conventional housing. In 1992-1993, annual consumption decreased to 11.8 kilowatt-hours per unit area (5.5% of consumption of apartments taken for comparison). Later, consumption decreased to less than 10 kilowatt hours per unit area per year.

The indicators were so small that specialists misinterpreted them for a long time. A significant reduction in energy costs, accounting for 90%, was achieved thanks to the use of highly efficient household appliances.

German experience was borrowed by Finnish architects and architects from other European countries. Since that time, more than 40 thousand passive eco-houses have been built in the world.

Passive house: construction in Russia

In the Russian Federation in Moscow, St. Petersburg, Nizhny Novgorod and Yekaterinburg, several objects are being or are being built using the basic standards on which passive houses are built. Projects of some of them will be considered further.

Project in the Moscow region

Among the projects of individual buildings with low energy consumption, it is possible to single out the "Active House" in the Moscow Region, whose heat supply is also passive.

Active houses are a structure with a different level of energy efficiency, but with great comfort, achieved with the help of automatic microclimate management at home by the "smart house" system, using renewable energy sources and its ecological purity.

The project was completed in 2011. It is a 5-storey building with an area of 229 square meters, two floors, a frame made of wood, insulated plates of mineral wool ISOVER, VELUX roof windows, a thickness of external fencing structures of 550-650 mm, resistance to heat transfer of the roof and walls 12, floor 14 (m ²⁾ · ° C) / W. The air exchange rate is 0.4 times per hour. The energy consumption for heating alone for the year is 38, and the total energy consumption is 110 kilowatt-hours per unit area per year.

Project in Nizhny Novgorod

Another example of a project with ultra-low heat consumption for heating needs is an eco-house near Nizhny Novgorod, completed in 2012.

Two-story building with an area of 141 square meters. Meter, designed for four people, is a structure in the form of a wooden frame, insulated with mineral wool plates ISOVER, with a window profile REHAU GENEO, three glasses, resistance to thermal transfer of walls 8,7, roofing 12,8, floor 8,9 m ² · ° C / W. The Zehnder ventilation unit with a recovery efficiency of 84% and an air exchange rate of 0.3 times per hour was used. The annual energy consumption for heating needs is 33 kilowatt-hours per unit area.

Poor housing - the enemy of energy efficiency

From the very beginning, the idea of a passive ecohouse assumed that the cost of such houses would be equal or slightly more expensive than the cost of ordinary houses. The meaning of the idea was the cheapness of such construction, the optimal ratio of price-quality and quick payback of expenses.

The main goal and problem is to equalize the cost of building such structures in the Russian Federation and the construction of conventional houses. The displacement of an energy-efficient home from the elite to the mass sector will not happen quickly. This will require, in addition to training architects, also the availability of the required skill level of builders, the use of high-quality construction materials and technological level, equipment and materials with special characteristics.

Russia's mass construction sector prefers to reduce the cost of housing due to the use of building materials of low quality and the exploitation of low-skilled labor. As long as such preferences remain, the transition to high-tech energy-efficient construction of mass housing looks unrealistic.

Perspectives in Russia

The planned reduction in energy consumption by 40% by 2020 is intended to reverse the situation in favor of energy saving technologies. The rate of resistance to heat transfer will increase from 0.52 to 0.8 m ² · ° C / W, and after - to 1.0. The use of recuperation in ventilation systems will be mandatory. At this time it is important to adapt and implement the foreign experience. By 2020, the construction of many dozens of passive houses is expected. By that time, the necessary conditions have already been created: banks will develop a system of preferential lending, designers, developers and builders will master new technologies. This will create a market and a steady demand of consumers.