【 Weak current College 】 on central air conditioning system and energy-saving

Summary: with the development of China's economic construction, central air conditioning more Purdue, central air conditioning energy consumption problem is increasingly important. This article from the project "life cycle" perspective, discusses the significance of the central air-conditioning energy saving and status from the engineering, engineering design, project construction and operation of management made a number of energy-saving measures and methods.

Key words: central air conditioning energy consumption and energy saving measures

1 Introduction

In all types of buildings, extensive use of advanced equipment and the appropriate equipment and central air conditioning system has become an important modern construction technology mark of modern architecture to create a comfortable and efficient working and living environment-an essential critical infrastructure. On these devices for the design, installation and operation of management not only directly related to the owners and the interests of users, but also on the Department of environmental protection. For example, in the intelligent construction, the central air conditioning system of monitoring points number often account for floor control point more than 50 per cent of the total, its energy consumption often account for the amount of total energy consumption, 5o%. Thus, the central air conditioning system in modern architecture is extremely important especially in modern intelligent building, central air conditioning system is indispensable. Thus the study of central air-conditioning system power consumption is especially important for significance. On the air conditioning system energy consumption of objectives to be achieved is how to create a good indoor small environment of use of energy, on the external environment of the minimum damage. to achieve the long-term objectives of sustainable development. The research was a very wide range of topics involving many disciplines.. This article from the project "life cycle (circlelife)" point of view, from the project status, engineering design, project construction and operation of the management of the central air conditioning system and energy-saving measures and methods.

2 practical engineering problems
Air conditioning project implementation is a systems engineering, it involves all relevant specialized in design and construction process in close coordination. While air conditioning projects mainly depends on the correctness of HVAC professional design and construction of rationality and air conditioning professionals. But in the more practical engineering, air-conditioning projects exist many problems. About the causes of air conditioning profession itself is not in this for detailed analysis.

This article only on the air conditioning engineering problems in the automatic control system for analysis, because along with the development of intelligent buildings, air conditioning air-conditioning automatic control system is an integral part of the system, and run the air conditioning system plays a key role. Air-conditioning automatic control system while increasing one-time investment, but can maintain good indoor environment on the basis of save operating costs. A design platform and run well-managed automation system can significantly save operating costs, so that the owners in a relatively short period of time to recover control system of an investment-you can substantially reduce the impact of the external environment. But because of the design and operation management reasons, most of the automatic control system, the design goal. Beijing Association have organized to engage in automatic control, computer, communications, air conditioning, and other experts on the development of intelligent buildings and technical connotation research went to Beijing as an example, the statistics user on building automatic control system operation of the evaluation are: satisfaction of only 30 per cent of the average total Pak per cent difference has accounted for 30 per cent. This state of affairs in addition primarily due to the low level of property management, automatic control design and air-conditioning design seriously. Air-conditioning automatic control system of project implementation are generally the following works: by the Design Institute of HVAC design professionals, and air conditioning air-conditioning automatic control requirements, and then submitted to the Institute of automation professionals air-conditioning automatic control design, or by automatic control equipment manufacturers to control part of programme design and construction drawing design, construction units installed debugging. Finally surrender to property management again for operational management. Therefore involves designing, construction unit and automatic control equipment manufacturers and decisions and control of building owners, etc. In these areas should form a close match Tai, but practice shows that the important links are often not very ideal convergence, legacy in the future, to the building automation system uptime and energy-saving effect have serious impact.

3 establish a system of energy-saving concept. Select sound design programme

Realization of the fundamental way air-conditioning energy saving lies clever use of indoor and outdoor conditions, maintenance structure and interactions of air conditioning equipment, select meet building energy efficiency requirements of the programme, both electricity made comfortable, efficient indoor environment, while at the same time the aim of achieving significant energy saving.

3.1 determination of indoor temperature.

The Chongqing, Shanghai, Guangzhou and other areas of practice shows that summer indoor temperature low 1 ° c or 1 ° c, in winter the high investment will increase 6% of energy consumption increased 8 per cent, and increase the indoor and outdoor temperature difference also hygienic requirements inconsistent with Taiwan. Comfort air conditioning in summer ideal indoor temperature is lower than the outdoor temperature 5-8 ° c as well.

3.2 envelope.

Air conditioning cold (hot) load can be divided into the envelope of cold (hot) load and Interior cooling (heat) load. The following terms from energy-saving doors and Windows-. Control window wall ratio: the window heat consumption accounted for the total heat loss in buildings 35%-45%, to ensure good indoor lighting, reasonably determine ratio of the wall is very important. As a general rule all toward the window wall ratio shall not be greater than the following numbers: 25%; in the North to the East and West to 30 percent; South to percent. Improve Windows tightness: room ACH by 0.9/h to 0.6 times the energy consumption of buildings/h, reduces the 8 percent, the design should be airtight good doors and Windows, and an additional seal is improving door air tightness of the important means to seal shall use good elasticity, with strict, received solid durable products, according to the specific situation of doors and Windows, using different seal, such as rubber, plastic or rubber seal on the combination of its shape can be a bar or a flush. Fixed method available paste, packed tight or nail knot.

3.3 air-conditioning heat and cold sources

Central air conditioning energy consumption generally consists of three parts, namely (1) heat source; (2) air conditioner terminal equipment; (3) water or airConveying system. This three-part, heat energy, or about energy consumption, total energy consumption is 50 percent. conditioning of important content. If you are putting their consumption of energy is converted into an energy source, preparation units are available once per time unit energy consumption by energy production volume of Ling or heat. This article uses the "once energy efficiency OEER (W/W) to indicate the energy consumption from units perspective. summer refrigeration: centrifugal and screw chiller O Mong R value maximum. absorption chiller OEER minimum; winter heating: screw, piston-type heat pump chiller OEER Supreme electric hot water unit minimum. i.e. the maximum energy consumption.

3.4 air-conditioning system.

General air conditioning water system of transmission and distribution of electricity, heating in winter period asked about the entire building power electricity 2o%-25%, in summer cooling period accounted for 12 percent to 24 percent of the energy-saving water system therefore has important significance for the present, the air conditioning system designed for a number of questions:

(1) select the pump is the design value find pump sample nameplate parameters, rather than by the pump performance curve selected pump models;

(2) not to carry out each water loops, hydraulic equilibrium calculation for pressure differential vastly circuit did not take effective measures, hydraulic, misadjustment phenomenon seriously;

(3) large capacity, small temperature difference widespread, design temperature for, backwater, but generally take 5cC, as measured in the summer the temperature of the chilled water return water is better for 35, poor only 1.5 ~ 2 ° c, resulting in the actual flow of water over the design of large 1.5 times so that the water pump power consumption increased significantly. Therefore, the energy-saving air-conditioning system shall be started from the following aspects into consideration:

(1) designers should pay attention to the water system design, serious water system loop calculations, and to take appropriate measures to ensure loop hydraulic balance;

(2) carefully proofread and calculate the correlation coefficient of chilled water system, the practical implementation of energy-saving design standard value, the active promotion of frequency he speed pump, winter and summer dual-speed pumps and other energy-saving measures; (3) of the refrigeration system cooling water inlet temperature of the high power consumption to host the di {has an important impact in General, certain cases, water inlet water temperature high 1 ° c, high energy consumption lithium bromide absorption chillers.

3.5 air-conditioning unit and terminal equipment

Home-fan-coil and from looking at the overall level of similar foreign products compared to the same, but the comparison with foreign advanced level of the main difference is the power consumption, coil weight and noise. Therefore design must pay attention to selection of light weight, unit fan power for carrying (hot) the unit quantity too. Air conditioning units should be chosen unit fan and air pressure matches the rational, less air leakage, air crew transfer coefficients too. Chen points, depending on the project, actively promote water-loop heat pumps, heat recovery, VAV, vwv and other energy-saving technology.

4 run management

4.1 do equipment and pipe insulation to reduce energy consumption of excessive air conditioning equipment and piping heat insulation, for savings in energy consumption, lower operating costs is also very important. If the insulation effect is not good or repaired insulation repair is not good, not only excessive consumption of cooling capacity, also due to the cold water temperature caused by excessive temperature rise on the air conditioning system in the process was unable to guarantee its dew point and allows the machine an air conditioned room relative humidity is exceeded.

4.2 regularly on air conditioning system water treatment

Water side of dirt, corrosion and MOSS on the impact of the refrigeration system is also extremely large air conditioning energy consumption levels of important reasons too dust in the air, water, bacteria, oxygen and certain harmful acid gas continuously from cooling tower into ^ cooling water system, although Bay refrigeration system, the more confined water of dissolved oxygen on frozen pipes also produce corrosive effect, cumulatively, air-conditioning equipment will produce dirt, rust, rust residue and microbial fault propagation resulting biological sludge, pipe plug, cooling capacity loss, waste of energy. According to the theory of computation, cold suspected of dirt, each additional 0.1mm, heat efficiency to reduce the electricity consumption of 30 per cent, an increase of 5-8 per cent.

4.3 central air conditioning for metering and charging

Central air conditioning for metering and charging is building a basic energy-saving measures in Europe and the United States from Xiao-is-f} mature technology. According to foreign investigation data show: centralized air conditioning metering and charging, the energy saving rate of up to 8 per cent to 15 per cent.

4.4 operation training

Strengthening air-conditioning operator staff training, improve management quality, air operators operating permit system. The regulation and implementation of energy saving measures, and operations staff are directly related to the technical quality.

5. concluding remarks

Reasonable design, careful construction and science of management on air conditioning energy is vital. Owners are advised to make early in construction management personnel selection and training necessary to hire experts to enhance all aspects of the construction process or even the entire process (from the design of the system operation) of supervision, to ensure the completion of the central air-conditioning system should at least be able to run properly, and thus pursue a degree of energy-saving, on this basis to implement comprehensive Optimizer runs in order to achieve maximum energy saving effect.