Building Energy Conservation Topics: New Technology

1. Ideal energy-saving building

An ideal energy-efficient building should satisfy the following three points with the least energy consumption:

• It is able to control the reception or blocking of solar radiation in different seasons and different regions.
• It is able to maintain indoor comfort in different seasons.
• It is able to achieve the necessary ventilation in the room.

The main ways to save energy in buildings include:

• Minimize the consumption of non-renewable energy and improve the efficiency of energy use.

(2) Reduce the energy loss of the building envelope.

(3) Reduce the energy consumption of building facilities operation.

In these three aspects, high-tech plays a decisive role.

Of course, building energy conservation also adopts some traditional technologies, but these traditional technologies can only be used in modern buildings on the basis of advanced experimental demonstration and scientific theoretical analysis.

2. Reduce energy consumption and improve energy efficiency

In order to maintain the environmental quality of the living space, heating is required to increase the indoor temperature in the cold season, cooling is required to reduce the indoor temperature in the hot season, humidification is required when it is dry, and dehumidification is required when it is wet, all of which often require energy consumption. to be realized.

From the perspective of energy saving, the efficiency of the heating (cooling) system should be improved, including the efficiency of the equipment itself, the efficiency of pipe network transmission, the metering of the user end, and the efficiency of the control device of the indoor environment.

All of these require the corresponding industries to adopt high-tech in design, installation, operation quality, energy-saving system adjustment, equipment materials, and operation and management modes.

For example, there are three new technologies in the energy saving of heating systems:

• Using a computer, a balance valve and its special intelligent instrument to reasonably distribute the flow of the pipe network, which not only improves the heating quality, but also saves energy.
• A heat distribution table and a temperature control valve are installed on the user’s radiator, and the user can consume and control heat energy according to their needs, so as to achieve the dual effects of comfort and energy saving.

(3) Use new thermal insulation material to wrap the heating pipeline to reduce the heat loss of the pipeline.

In recent years, the low-temperature floor radiation technology has been proved to have good energy-saving effect. It uses cross-linked polyethylene (PEX) pipes as water pipes, and uses a special method to circulate in two directions in the ground floor. In winter, low-temperature hot water (geothermal, Provided by solar energy or various low temperature waste heat).

In summer, the input of cold water can reduce the surface temperature (domestic only for heating).

Compared with the radiator that mainly uses convection heat dissipation, this technology has the advantages of uniform indoor temperature distribution, comfort, energy saving, easy measurement, and convenient maintenance.

3. Reduce the energy loss of the building envelope

The energy loss of the building envelope mainly comes from three parts: external walls, doors and windows, and roofs.

These three energy-saving technologies are of great concern to the construction industry of all countries.

The main development direction is to develop efficient and economical thermal insulation and thermal insulation materials and practical construction technology to improve the thermal insulation, thermal insulation performance and airtight performance of the envelope structure.

• Wall energy saving

The traditional method of increasing the thickness of the wall with a heavy single material to achieve thermal insulation has been unable to meet the requirements of energy saving and environmental protection, and the composite wall has increasingly become the mainstream of the wall.

The composite wall generally uses block material or reinforced concrete as the load-bearing structure, which is compounded with thermal insulation materials, or uses thin-walled materials for thermal insulation and thermal insulation materials as the wall in the frame structure.

The main thermal insulation and thermal insulation materials for buildings are rock wool, slag wool, glass wool, polystyrene foam, expanded perlite, expanded vermiculite, aerated concrete and rubber powder polystyrene particle slurry foamed cement insulation board, etc.

The production and production of these materials require special technology and special equipment, which are not within the reach of traditional technology.

It is worth mentioning that the rubber powder polystyrene particle slurry is made by mixing the rubber powder material and the polystyrene particle light aggregate with water into a slurry, which is smeared on the outer surface of the wall to form a cavity-free thermal insulation layer.

Polystyrene granular aggregate is made of recycled waste polystyrene board by crushing, and the rubber powder is mixed with a large amount of fly ash, which is a kind of waste utilization, energy saving and environmental protection material.

The composite technology of the wall has three types: internal thermal insulation layer, external thermal insulation layer and sandwich thermal insulation layer. China adopts the sandwich insulation method more.

In European countries, most of the externally attached foamed polystyrene boards are used. In Germany, external thermal insulation buildings account for 80% of the total construction, and 70% of them are made of foamed polystyrene boards.

(2) Doors and windows save energy

Doors and windows have the functions of lighting, ventilation and enclosure, and also play an important role in the treatment of architectural art.

However, doors and windows are the parts that are most likely to cause energy loss.

In order to increase the area of lighting and ventilation or to express the character of modern buildings, the area of doors and windows of buildings is getting larger and larger, and there are more all-glass curtain wall buildings.

This puts forward higher requirements for the energy saving of external maintenance structures.

The energy-saving treatment of doors and windows is mainly to improve the thermal insulation performance of materials and improve the airtight performance of doors and windows.

From the perspective of door and window materials, in recent years, there have been some energy-saving products with high technical content, such as aluminum alloy thermal insulation profiles, aluminum-wood composite profiles, steel-plastic integral extrusion profiles, plastic-wood composite profiles, and UPVC plastic profiles.

Among them, UPVC plastic profiles are widely used, and the raw material used is rigid polyvinyl chloride, a polymer material.

It not only has less energy consumption and no pollution in the production process, but also has a small thermal conductivity of the material, and the multi-cavity structure has good sealing performance, so the thermal insulation performance is good.

UPVC plastic doors and windows have been used in European countries for many years, and plastic doors and windows in Germany have accounted for 50%.

Since the 1990s in China, the amount of plastic doors and windows has been increasing, and it is gradually replacing energy-intensive materials such as steel and aluminum alloys.

In order to solve the problem of excessive energy loss caused by large-area glass, people use high-tech to process ordinary glass into insulating glass, coated glass (including reflective glass, heat-absorbing glass), high-strength LOW2E fireproof glass (high-strength low-emissivity coating fireproof glass), glass with metallic silver layer and most special smart glass by magnetron vacuum sputtering method.

Smart glass can sense and respond to changes in external light. It has two types:

One type is photochromic glass. When the light is irradiated, the glass will be dimmed, and the light will not pass through easily; when the light is stopped, the glass will regain its brightness and the light can pass through.

When the sun is strong, it can block solar radiation heat; when it is cloudy, the glass becomes brighter, and sunlight can enter the room again.

The other type is electrochromic glass, which is coated with a conductive film and a color-changing substance on two pieces of glass. By adjusting the voltage, the color-changing substance is promoted to change color, and the incoming sunlight can be adjusted (but it cannot be practically used because of its high production cost) , These glass have good energy saving effect.

• Roof energy saving

The thermal insulation and heat insulation of the roof is one of the key points of the energy saving of the building envelope.

Insulation layer is installed on the roof in cold areas to prevent indoor heat loss; in hot areas, insulation and cooling layer is installed on the roof to prevent the radiant heat from the sun from being transferred indoors; and in areas with cold winters and hot summers (the Yellow River to the Yangtze River Basin), building energy saving It is necessary to take into account both winter and summer.

The commonly used technical measures for thermal insulation are to set lightweight materials with low thermal conductivity under the roof waterproof layer for thermal insulation, such as expanded perlite, glass wool, etc. (this is the positive laying method); polystyrene can also be set above the roof waterproof layer Foam (this is the inverted method).

Another thermal insulation method in the UK is to use recycled waste paper to make paper fibers. This kind of paper fiber has extremely low energy consumption and excellent thermal insulation performance. The paper fibers are treated with borax flame retardant and can also be fireproof.

During construction, the nail layer of the roof is interlayered first, and then the paper fibers are sprayed into it to form a thermal insulation layer.

The methods of roof insulation and cooling include: overhead ventilation, roof water storage or regular water spray, roof greening, etc.

The above methods can meet the requirements of roof energy saving to varying degrees, but the most respected is the use of intelligent technology and ecological technology to realize the desire of building energy saving, such as solar collector roofs and controllable ventilation roofs.

(3) Reduce the energy consumption of building facilities operation

Heating, cooling and lighting are the main parts of building energy consumption. Reducing this part of energy consumption will play an important role in energy saving. In this regard, some successful technical measures are very valuable for reference, such as the British Building Research Institute (English abbreviation: BRE). ) is an example of an energy-efficient office building.

The office building adopts an advanced energy-saving control system in the building envelope, and the interior of the building adopts a transparent interlayer to facilitate natural ventilation; the air is fed through the lattice windows at the back of the building, and the lattice windows on the top wall of the building are exhausted. Creates natural ventilation throughout the building.

The office building uses high-efficiency heating and cooling boilers and conventional boilers, and the two boilers are controlled by a computer system and used alternately.

The room temperature is regulated by a system of heating and cooling ductwork embedded in the floor.

The building also adopts the technology of inputting cold water under the floor and cooling through the radiator. The cold water is pumped from the ground into the radiator through the deep well under the garage and pumped into the radiator, and then recharged by another return well next to the building.

In order to reduce artificial lighting, the office building adopts an all-round combined lighting and lighting system, which is controlled by the building management system; each unit has daylight, and users and managers can remotely control the system through detectors; in the 100-seat lecture hall, There are two types of lighting systems, allowing 0% to 100% brightness, using energy-saving tubular fluorescent lamps and incandescent lamps, so that every audience can enjoy the same good visual effect and suitable temperature.

(4) Development and utilization of new energy

While saving non-renewable energy, human beings are still seeking to develop and utilize new energy to adapt to the reality of population increase and energy depletion. This is the mission entrusted to modern people by history, and the effective development and utilization of new energy must rely on high technology.

For example, the development and utilization of solar energy, wind energy, tidal energy, hydropower, geothermal energy and other renewable natural energy sources must rely on advanced technical means, and must be continuously improved and improved in order to achieve more effective use of these energy sources.

For example, people can not only use solar energy for heating in buildings, but also solar water heaters can convert solar energy into electrical energy, and integrate photovoltaic products with building components, such as photovoltaic roof panels, photovoltaic exterior wall panels, photovoltaic sunshade panels, and photovoltaic window walls. , photoelectric skylights and photoelectric glass curtain walls, etc., turn energy consumption into production capacity.