【 Weak current College 】 large-scale commercial building low-cost energy saving technology analysis

Summary of the article describes the current in the commercial building energy-saving, central air conditioning, lighting, water supply and drainage, electrical systems, low-cost technology, and comparison of various technical analysis, pointing out that commercial building low-cost energy saving should give priority to host House fuzzy frequency control system; energy-saving lamp and lamp replacement; cooling water saving technologies; improving power quality equipment is installed.
Keywords for commercial building low-cost energy saving 1 preface
National economic and social development of the "eleventh five-year plan" outline of the 2010 unit GDP energy consumption than th final cut 20 percent, "eleventh five-year plan" period the average annual consumption 4%, in 2006 average saving 1.2 per cent. In October 2007, the national people's Congress adopted the People's Republic of China energy conservation law (Amendment) Act, clearly defined, comprehensive energy consumption 10 000 tonnes or more using units to be able to focus on monitoring unit, with a focus on using units need to be focused on energy planning and energy saving, and large commercial buildings are using units belonging to the key. In an increasingly competitive, energy-saving problems becomes even more pressing.
2 status in large commercial buildings energy consumption
Economic growth, China's commercial building (hotels, office buildings, shopping malls, comprehensive building, etc.) the growing areas, business buildings in the area of national building area 2

5.4 percent, has been built around the advanced hotel 2000, more than 3000 high office, more than 800 large hospitals, more than 800 large shopping malls.
In General, large-scale commercial building in addition to the special equipment to use, the main energy consumption include central air conditioning system energy consumption, lighting system energy consumption, water consumption, power and other energy consumption. In the Shanghai area, for example, building energy consumption ratio in the lighting system is about 10 per cent to 20 per cent of the energy consumption of air conditioning system is about 40% ~ 60%, other power systems energy consumption is approximately 30 per cent to 40 per cent.
3 large commercial buildings mainly low-cost energy conservation measures
For large commercial buildings, the main energy-saving object has central air conditioning, water supply and drainage, lighting and electrical energy.
3.1 central air conditioning low cost technology
Central air conditioning energy consumption accounts for commercial buildings energy consumption by 40% and 60%, therefore the commercial central air conditioning energy efficiency is an important means of building energy-saving. From the current central air conditioner is running, the prevalence of the "big horse cart", that is, central air conditioning systems and water pumps and other equipment selection is greater than the actual load on demand system, causing a lot of energy wasted, while for central air conditioning energy saving means a lot, but it is difficult for most of the cost is high, such as the use of ground source heat pump technology, water and ice storage technology, etc. At present, can be applied in central air-conditioning energy saving and lower cost technology means mainly has following several.
3.1.1 central air-conditioning automatic control technology (BA)
Central air-conditioning automatic control technology can conveniently and building automatic control technology to achieve integrated networking control may be based on commercial building real-time load adjustment hosts and other air conditioning equipment, and guarantee the indoor temperature and humidity, as much as possible energy savings. Central air-conditioning automatic control system contains and heat source (chiller, boilers, etc.) of the control, pump (frozen pumps, cooling pump, heat pump, fill the water pump, etc.) control, cooling devices (cooling towers, cooling wells) control, Terminal devices (air supply unit, a combined air-conditioning units, fan-coil, etc) control and a variety of fans, control valves, etc.
With central air-conditioning automatic control technology of the main advantages are: can automatically detect the temperature, the lower the energy consumption of air conditioning equipment; provides the ability to automatically adjust the comfortable environment; the prevention of sudden accident, protection equipment investment; extended equipment life and reduce administrative costs; the entire architecture of the unified management of all air conditioning equipment; in the graphical user interface to complete all operations. Its main weaknesses and shortcomings in the second scene: the need for programming, human factors, due to the lack of advanced control algorithms for model imperfections, energy-saving effect; later maintenance cost is high; it is difficult to assess the energy saving effect.
3.1.2 host room fuzzy variable frequency control technology
Host room fuzzy variable frequency control system mainly on freezing room of dissipation devices for energy saving operation management, due to freezing room equipment energy accounted for commercial buildings energy consumption by 50 percent, so this technology in commercial buildings is very valuable.
Host room fuzzy variable frequency control technology principle is shown in Figure 1. Through comprehensive parameter acquisition, using modern technology for fuzzy control of frozen water system is expected to control, cooling water system for Adaptive fuzzy optimal control and host system of indirect (or stop) control for air conditioning refrigerant flow follows the load change dynamic adjustment, ensure that the entire air-conditioning system remains efficient and coordinated manner, thereby minimizing the energy consumption of air conditioning system, for host energy-saving housing equipment 20% ~ 40%.
Host room fuzzy frequency conversion technology main advantages are: energy saving is limited to host housing, renovation of the cycle time is short, easy to implement; large mall air-conditioning energy saving rate is as high as 20 percent less investment, payback period is short, generally for around three years, or you can easily move the frequency conversion control terminal equipment into the system; this system and BA system networking or used is also very convenient. Its deficiency is that energy conservation rate changes with the seasons and flow fluctuations, energy saving rate determination of workload is large; the system life short, about 15 years.
3.1.3 fresh air ventilation technology
Large commercial buildings as the crowd was extremely dense, and air conditioning run-time, generally subject to a floor outside other floors and doors are closed, so that the Interior is very little natural ventilation times. Need to rely on fresh air to the air conditioning system delivery, while indoor ventilation system need to indoor air and fresh air discharged from the same quantity to meet the outdoor, on the health of the population. As a result of summer low exhaust temperatures and outdoor air temperature is high, let the fresh air and exhaust air to air heat exchange, to lower the temperature of air, you can save considerable amount of cooled refrigerators and, consequently, is a science of energy-saving measures. At the same time, strengthen ventilation of indoor and outdoorIs thoroughly improved indoor air quality shopping centres. If operating conditions in the summer, when the room exhaust (26 ° c) cold air energy through a heat exchanger to the outside (33 ° c) and hot air cooling to 29 degrees centigrade of fresh air into the room (as shown in Figure 2), the air conditioning only need it to 3 ° c to maintain cooling comfort of room and fresh air.
With ventilator technology main advantages are: you can set the amount of cold and hot air recovery, substantial savings freezer or boiler energy consumption; large mall air-conditioning energy saving rate of up to 20 per cent less investment, payback period is short, generally for two years. Its main weaknesses and shortcomings is that the volume is large, larger air conditioning room, and the transformation of wind pipes system, built shopping centres of difficult; because of the need to periodically clean the dust in the air, thus maintaining workload is relatively large.
3.2 lighting energy-saving technology
In commercial buildings, lighting energy consumption generally is second only to central air conditioning, but the lighting energy-saving alteration must be to ensure that construction on the basis of internal illumination to complete, if at the expense of illumination to realize energy makes building staff comfort, affecting commercial building's operating results. Common lighting energy-saving low-cost technology has replaced energy-saving appliances, installation of lighting and lighting brownout automatic control system.
3.2.1 replacement energy-efficient lighting equipment
Currently, commercial buildings use lamp T8 type fluorescent lamp, mostly, compact fluorescent lamps or used to highlight the characteristics of goods and construction and use of metal halide lamps, halogen lamps, etc. Major shopping malls due to practical use needs and installation characteristics, lamp replacement difficult, but in large supermarkets, office buildings, hospitals and commercial building large underground car park in general are using the T8 fluorescent lamps, lighting time is very long, and therefore, replace the lamp has a vast potential for energy saving.
Statistics show that CFL than incandescent lamp power saving 80%, life is 5 times that of incandescent lamps are incandescent lighting efficiency 3.5 times. Although the energy-saving lamps costs less than incandescent lamps to several times, but the price gap can later save out of use, and more cost-effective.
Practice has proved, without affecting the lighting effect of energy saving light source without replacement and lamps are the most effective lighting energy-saving measures. However, current energy-saving lamps also depends on the quality of products, select replace lighting should strictly follow the requirements of the actual use to choose the right product.
3.2.2 Installing lighting apparatus
Install lighting saver can be a constant voltage, filtering, power factor, achieve energy and prolong the service life of lamps. However, the installation of lighting and electrical power quality better building effect is not evident, some will reduce building illumination, in contrast to the strict requirements of the occasion, not suitable for use in lighting energy saver.
3.2.3 lighting control system
Intelligent lighting control system can be intelligent, flexible control of large-scale commercial building lighting system start-up and shutdown and dimming, while ensuring illumination lights system as possible more energy and more artistic performance ability. Include the automatic, scheduled to open and close the lights; according to illumination automatically open and close; according to illumination automatically dimming; transform preset scene lighting mode.
Lighting control technology of the main advantages are: can flexibly scene control; depending on the illumination or access control lighting; you can use a computer to control management, unified efficiency; you can remote control. Its main disadvantages and weaknesses are: the system structure is complex and requires a higher level of maintenance personnel; energy-saving effect assessment more difficult; the system to improve management efficiency, energy saving as a supplement, measurable energy saving rate is not high.
3.3 building energy-saving to/drainage system
Commercial building water consumption is an important part of building energy consumption, at present, in the face of the increasingly scarce water resources, commercial building-saving also has important significance. However, due to its architectural structure complex, difficult, some technologies (such as reuse, etc.) in the existing building is difficult to achieve. Commonly used to/drainage improvement technology at low cost are: replacement of water-saving appliances and air-conditioning cooling water saving.
3.3.1 replace water saving appliances
Use water-saving appliances are commercial building-saving the most direct means, such as installing water-saving toilet, the installation of infrared sensors taps, and water-saving shower; or install water saving valves (can to tap or shower head of water with bubbles), save a lot of water.
3.3.2 cooling water saving technology
Air conditioning cooling water consumption, water consumption accounted for summer shopping malls, office buildings, total water consumption by 50%, for a cycle water 1000m3/h of water cooling system, good water evaporation is about 8.5m3/h, about 100 tonnes per day; bleach water about 2.5m3/h, about 30 tonnes per day; sewage water about 4m3/h, about 50 tons per day. Which, in addition to the evaporation loss of water is necessary, bleach water and sewage water has a huge water saving space.
In the cooling tower fans down, through a certain shape retaining plate, prevent drops of water splashing, can effectively reduce the cooling water 80% bleach, but air resistance.
Utilization of cooling tower blowdown water for flushing and green irrigation is important cooling water-saving measures. In General, large-scale commercial building of flushing water greater than cooling water discharge water volume of 50 percent, with cooling water for flushing benefits: increase sewage water, increase water cooling; saving the cooling tower; dosing of low-water supplement reduced cooling water temperature, thus reducing the power consumption for cooling tower and the host.
3.4 electrical energy
Commercial construction electrical energy-efficient renovation of the main measures have improved power quality equipment is installed, the kinetic energy-saving, Elevator Escalator energy feedback control system.
3.4.1 installation improved power quality equipment
Harmonic and reactive power of a large number exists, not only to commercial construction equipment in normal use has an adverse impact, or interfere with electric power metering, resulting in a loss of power. Improved power quality through the installation of devices that can effectively improve the commercial building of power quality, hotel and office building of energy-efficiency can reach 8%-15%.
Improve the quality of electricity-saving advantages: equipment installationIn building distribution and modification does not affect the amount of business; renovation project is small, easy to implement; small investment, quick, energy-saving effect is easy to measure and evaluate. There are major shortcomings: high-voltage side of energy saving devices installed in order to obtain a license in the electricity sector, to the transformation of a certain degree of difficulty; power quality with the different projects have different solutions, the workload of the early research assessment.
3.4.2 elevator kinetic energy-saving technology feedback
Inverter for elevator through motor can slow down, or car and to re-balance the poor quality of the block of the elevator runs of mechanical energy into electrical energy stored in large inverter DC link capacitors, through active energy feedback will large capacitance stored electricity consumption to return to the free power grid. To achieve energy-saving purposes, without the power consumption of heating power resistors, greatly improved the system's operating environment.
Through analysis and prototype testing shows that the elevator ramp speed faster, higher floor, the smaller the mechanical drive consumption, you can echo power grid, the more energy, up to echo power up to lift 40 per cent of the total consumption.
3.4.3 escalator energy control systems
In the escalator entrance to increase passenger sensor, no passenger arrival stop running. When a passenger arrives at the entrance to the induction area, lift automatically start running. In a migration from cycle arrival without new passengers, the elevator is automatically stopped. Transported passengers cycle from the last passenger arrives.
Elevator for starting and stopping the seamless, no beat feel. Start gradually speed up to full speed, stops gradually slow down to zero speed.
Escalator energy control system energy-saving efficiency, usually can achieve 20%-60%.
4 comparison of energy-saving technology
At present, the commercial building energy-saving technology many, combined with the current status of energy efficiency in commercial buildings, can these low-cost technology for fuzzy analysis comparison, compare the results are shown in the following table.
By comparison shopping centres can be found, energy saving should give priority to select the following four techniques: host room fuzzy variable frequency control system; energy-saving lamp and lamp replacement; cooling water saving technologies; improving power quality equipment is installed. Their common characteristic is mainly reflected in:
(1) energy-saving technology is mature, energy saving, small risk;
(2) energy-saving transformation of simple, low cost, does not affect the normal use of commercial buildings;
(3) energy efficiency can be measured, to facilitate the comparison and analysis of energy saving;
(4) investment payback period is short, high return on investment.
5. concluding remarks
According to statistics, in large commercial buildings energy consumption, its energy consumption per unit area is home to 10-15 times, about 25 per cent to 30 per cent of the energy-saving-space. Due to cost reasons, large commercial buildings in favor of the adoption of no-cost or low-cost energy-saving technology transformation. From energy-saving investment and earnings comparison, energy saving should give priority to host House fuzzy frequency control system, energy-saving lamp and lamp replacement, cooling water saving technologies and improved power quality equipment is installed. &
Reference documents
1 Chen. Li Yuan new commercial building with central air-conditioning energy saving and investment pattern analysis. "energy saving" 2007 (4); 46 ~ 50
Mira Li 2-Shanghai public buildings energy consumption survey with the operational management of the HVAC "2005 (5); 134-136