【 Weak current College 】 Central air-conditioning system saving technology---Power By 【 China power house network 】

An introduction to the access, since the 1990 's, along with economic development and improve living standards, the air conditioning to many cities of shopping malls, offices, conference rooms, hotel, hotels, stations, theatres and other public buildings and residential. These air conditioning consume large amounts of electrical energy, causing the city to a sharp increase in non-industrial power. 　　 Refrigeration and air conditioning in the social scale, in the application only to Beijing, for example, in July 2002, the instantaneous load power has risen to 782 million kilowatts, including air conditioning, cooling and electricity accounted for the total load in Beijing area power of 38 percent. Xiamen in August 2003, the air conditioning electricity accounted for 32 per cent of the load.　　 Many urban air conditioning energy consumption accounts for the total electricity consumption of 30 cities-40%. In nearly all industrialized countries, air conditioning and refrigeration equipment, the power consumption is the first big.　　 China is a large population, relative shortage of resources.　　 At present, China's per capita resources amounting to half of the world's average level, per capita energy consumption for the world average of 55 per cent.　　 China's per capita consumption is only about 1000 kWh, equivalent to a world average consumption level of 50%, far below the developed countries per capita electricity consumption level of 2 million kWh. On the other hand, each $ gross energy consumption in the world, as India's second point twice, as developed by four to six times; the use of energy efficiency of equipment on the low side, and cause the waste of energy, energy efficiency is not high.　　 Winter and summer, the air conditioning of buildings air conditioning energy consumption in occupies the entire building energy consumption by 50 percent. Take the necessary measures for energy efficiency in buildings can reduce air conditioning equipment of more than 25%of energy consumption, therefore take appropriate measures, of great significance.　　 For example, the General electric energy to the hotel, including air conditioning energy consumption accounted for half of the total energy consumption, the second is the hot water.　　 A hotel of energy consumption, the largest proportion, second only to the human cost. On energy, several data: China's per capita energy resources only to the world average of 40%-50%. Second only to China's energy consumption in the United States, ranked second in the world.　　 A lot of energy consumption is causing serious environmental pollution.　　 Because my energy in coal accounted for about 3/4. An average of 1 ton of coal combustion emissions CO2 490 kg, dust 13.6 kg SO2 14.8 kg. Therefore, the energy saving not only in the contemporary, and protection of the environment for future generations. Second, central air conditioning system consists of central air conditioning system for central air conditioning system is processing and distribution of cooling capacity of air conditioning systems, typically there are three ways to indoor air for cooling and warming treatment: 1.　　 Main road to the end of each room (fan coil) 2. wind pipeline to all rooms air 3.　　 refrigerant directly into each room at the end of the pipe to the end of each room (fan coil) half a centralized system for building air conditioning common forms of indoor air and outdoor fresh air mixture is processed through the ventilation pipe to each air-conditioned room is a common way. Air supply before entering each room must be made through centralized air treatment appliances (air box) for cooling/heating, humidification/dehumidification process. Then through the main duct and various branch pipe duct into each air conditioned room composed of a central air conditioning system, central air conditioning system is driven by a series of fluid flow in sports equipment (such as pumps, fans and compressors), various types of heat exchanger(such as fan coil, evaporator, condenser and intermediate heat exchanger, etc.) and connect various devices for pipes (wind pipes, water pipes and refrigerant pipes) and valves. System generally can be divided into the following five cycle: (1) indoor air circulation; (2) cooling water circulation; (3) refrigerant cycle; (4) cooling water cycle;　　 (5) outdoor air circulation. Overall, constitute the central air conditioning system of the equipment and machinery mainly heat and fluid machinery.　　 Heat exchanger is as high and low temperature two working fluid energy exchange equipment. When any group of heat exchanger efficiency is not good, will increase the system power consumption rate (kW/RT), is not a system power consumption increased, is freezing capacity decrease. Fluid machinery is to promote working fluid cycle power plant, its consumption, W = Q H h/η. Electricity consumption of many decided to run hours h, conveying working fluid flow q, the working fluid circulation needed lift h and efficiency η, reducing any of them, you can achieve the purpose of energy saving.　　 Third, central air conditioning system design on energy saving in order to achieve energy-saving air-conditioning system, first reasonable design. Central air conditioning system for air conditioning construction services, therefore, the energy-saving design can be divided into two aspects, one is to reduce air conditioning heat load of the building, on the other hand is to improve the efficiency of the air-conditioning system.　　 Air conditioning buildings during the summer months depending on the refrigerator will indoor thermal loads are moved to the outside. Obviously, reducing heat load in a room, refrigerator running time would reduce the energy consumption of central air conditioning system is reduced. Indoor thermal load from two aspects, one is from indoor and outdoor temperature difference arising out of the heat exchange, on the other hand is the interior lighting and equipment for the generation of heat load.　　 Therefore, you can take the Sun, air tightness and heat insulation and other measures to reduce Interior energy-saving heat load up. 1. reduce indoor thermal load (1) solar radiation directly reduce sun roof, wall, window and through the window into the rooms, you can use the cantilevered, sun visors (tents), coated glass, etc; reduce external walls, roofing absorb sunlight radiation heat, use light-colored exterior wall finishes, the insulation in the roof and exterior side, or overhead roof roofing.　　 Add shading to summer cooling load (or cooling) reduce the very obvious. According to the China Academy of determination, in the cement roof brush whitewashed, summer roof surface temperature to reduce 16-19 ° c. (2) air-tightness to improve Windows and doors to prevent air gaps. Use of PVC is not hermetically and thermal resistance, and can reduce noise, reduce dust. Or use ◆.seal, improving door air tightness. ACH room from 8 to 5 times, buildings of cold consumption reduces the 8 per cent of the leftTo the right. Therefore design should be airtight good doors and Windows.　　 Installing doors and Windows closed is to improve airtightness of important means. Under Windows, using different seal if rubber bar, plastic or rubber combination of seal. (3) thermal insulation used on thermal insulation for walls, roof, doors and Windows, insulation, such as rock wool, slag wool, glass wool, foamed polystyrene, perlite, aerated concrete, polyurethane rigid foam, PVC plastic doors and Windows, insulating glass, etc., in order to reduce the heat transfer coefficient of envelope.　　 Use of hollow block, two-story window, use the air insulation, but also played the role of thermal insulation. Addition of external walls and roof insulation for both winter and summer seasons can benefit. (4) control window wall than window wall than is the window openings and wall area ratio, increasing the ratio of detrimental air conditioning energy efficiency in buildings.　　 Heat loss through the window of the total heat loss in buildings account for 35% to 45%. 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 facing 30%; South to 35%. L reduce Windows, wall area ratio, to reduce summer cooling loads be better results.　　 Form design and development experience in a single window, double glass and coated glass phase.　　 The most advanced energy saving window is a super energy efficient Windows, although Super energy saving window than ordinary window price high (20-50) per cent, to energy saving calculation, it's payback time for only 2 to 4 years. (5) lighting l in our country, lighting electricity consumption is the total amount of 10% or more, lighting electricity often directly into air-conditioning cooling load. Large area for air conditioning, lighting, large capacity, you should use a combination of lighting and air conditioning system.　　 Note the use of energy-saving lamps, energy saving light emitting efficiency is high, is about 5 times that of incandescent lamps.　　 That is, the same brightness, energy-saving lamp power consumption is only 1/5 incandescent lamps. Use energy-saving lamps not only reduce lighting energy consumption, but also can reduce air conditioning load. 2. improve the efficiency of the air-conditioning system (1).　　 the reasonable choice of refrigeration appliances (cold source) configure multiple compressor chillers with significant energy saving effects. Because such a unit in part load still have higher efficiency, and the crew starting can implement order starting each compressor, electric shock, energy loss.　　 In addition, you can either change the compressor starting sequence so that each compressor wear equilibrium, extension of service life. But the number should not be too many cold water unit number to choose 2 ~ 3 units, cooling capacity is large, and should not exceed 4 single, stand-alone refrigeration capacity size should be reasonable.　　 (2) a reasonable selection of the host volume for security reasons, most of the cold water host capacity than actual peak heat load greater than 20 percent. However, the actual peak thermal load in the frequency of the year is quite low, the annual average is about heat load peak heat load (60 ~ 70)%, making the annual average of heat load only cold water in the host volume (50-60)%. From here, the resulting cold water host most of the time in low-load operation.　　 Cold water host load rate at 60% following operation efficiency.　　 Therefore, the host shall not contain selection is too large. (3) a reasonable selection of refrigeration mode with waste heat (such as steam, hot water and heat emissions from furnaces, etc.) available for use, should be preferred LIBR absorption chiller for cooling of the air conditioning system.　　 (4) configuration of high-quality energy-saving equipment design and manufacturing technologies in recent years, the new listing of cold water in the host's power consumption rate of more than 20 years ago the production of cold water host approximately 35% reduction. Therefore, in due course, the old host to host high efficiency cooling water is very feasible. Under instance, a user in order to solve the problem of CFC refrigerant, one has been running for about 15 years of the cold water host, 350RT to meet peak demand of cold-water host, 300RT equipment investment of about four years.
4. run the adjustment and maintenance of energy-saving 1, air conditioning system and economic operation and technical management (1) the periodic inspection and improvement of the support structure, equipment, water and air transportation systems for thermal insulation properties, references GB4272 implementation. (2) to meet the production process and comfort conditions, a reasonable lower buildings air conditioning temperature and humidity standards appropriate to increase the return of air temperature andthe temperature difference for backwater.　　 (3) to ensure the minimum ventilation rate, reasonable control and correct use of the outdoor air.　　 (4) the periodic inspection and maintenance of the water, the air transportation system, reduce system leak.　　 (5) regular maintenance, calibration of automatic control and monitoring meter dry instrument.　　 (6) strengthen air conditioning water system water quality management.　　 (7) the establishment of operational management, maintenance, repair, and other rules and regulations.　　 (8) the establishment of operational logs and device technology archives.　　 (9) the management and operations personnel to go through the training, examination before appointment. (10) the competent authorities regularly send personally check the implementation of the relevant rules and regulations. 2. control of reasonable operating parameters (1) indoor temperature and humidity from the energy point of view to determine the indoor temperature and humidity standards is an important factor in saving energy.　　To ensure the production process and human health, the summer room temperature increase of about 1 ° c, could reduce the thermal load 11.2%. In the summer such as indoor air humidity from 60% to 70%, you can conserve energy at around 17%.　　 According to the information measure, only 1 ° c room temperature increase in the summer, you can make to reduce air conditioning project total investment of approximately 6%, operating costs decrease of 8%. United States National Bureau believes the summer room temperature increase from 24 ° c, could energy-saving 26.7 ° c 15%. (2) a new air conditioner fresh air load accounted for a total load of 20% to 40%, the level of the standard values, and the relationship between significant energy saving, cannot be neglected. The introduction of fresh air is primarily intended to meet the health needs of people and part of the process air conditioning needed to maintain a pressure differential of indoor and outdoor. But how many of the new amount of wind has a direct impact on the air conditioning load, thus affecting the air conditioning system with fan, cooling water pumps, compressors, cooling water pumps, cooling fan power consumption. General design is to staff up and activities of the most intense circumstances ventilation rate.　　 ButActually used it almost does not need to use so much fresh air, resulting in most of the air conditioning sessions are in the State of energy consumption. A more effective approach is to the carbon dioxide concentration in indoor air to control fresh air. Large hotels, hotels and public places, shopping malls, restaurants and function rooms and large Conference Hall, etc., need to be fed into the new amount of wind is large. In the entire system of the actual operation of the outdoor air temperature and humidity with the season.　　 Therefore, the timely adjustment of good fresh air and return air ratio can save energy. For example, a shopping mall in Japan from Monday to Friday will be reduced by 50% for fresh air, total cooling load reduction 30%.　　 (3) chilled water supply and return water temperature difference general air conditioning water system of transmission and distribution of electricity, in summer cooling period accounted for the entire building dynamic power consumption of 12%-24%, therefore energy-saving water system.　　 At present, large capacity, small temperature difference widespread, design temperature for, generally take back 5 ℃. Survey test some high-rise hotel, hotel air conditioning water system information data show that summer chilled water system for return water temperature is good for 3-4 ° c, poor only 1-1.5 ° c, resulting in the actual flow of water than needed, so that the water system power consumption increased significantly.　　 (4) of the cooling water inlet temperature according to experience, cooling water inlet temperature decrease 1¡æ can economize 1.5 ~ 2.0%. Cooling water inlet temperature should be in line with the cold water temperature in the host properties and outdoor, wet bulb temperature constraints as much as possible to reduce, to save power consumption of cooling water host. In lower cooling water temperature to reduce power consumption when cooling host, cooling towers, both low power consumption and a best running efficiency.　　 Cooling towers and water together to consider the operation of the host in order to make the system overall efficiency. To achieve optimum control, cooling water temperature setting with an outdoor temperature, should be wet-bulb temperature.　　 (5) the amount of cooling water cycle to reduce the amount of cooling water circulation, reduces the power consumption of cooling water pump. If a host with cold water and cooling towers to choose a larger difference in design, the flow can be reduced, thereby reducing the cost of cooling water pumps for the start up and running costs.　　 (6) cooling fan control in most of the design, a cold water hosts with a cooling towers and water tower in stop-and cold-water host linkage. As a result of medium and large number of cold water host system was on the high number of cooling towers makes it more difficult to manage and maintain, and not with the air conditioning load and outdoor temperature changes and adjusts the fan condition of electricity consumption. When the water handling capacity greater than 300 m3/h, the square Tower can realize many fan control.　　 The number of fans can grow along with the quantity of water. Square windy model cooling towers, as summer outdoor wet-bulb temperature changes at will increase or decrease the number of fan and temperature, for larger areas more conducive to saving energy.　　 (7) the running time of adjustment, bar, summer Entertainment's operating time is typically only evening business, time is about 19-22. Business front 2 ~ 4h will air conditioning system operational, using the envelope's cool capabilities enable the temperature slowly within the Office down to the lower value of the design temperature or slightly lower than the value. So when the business is growing indoor thermal load form the peak, the air conditioning equipment still below the peak load correctly, Precooling "," reduce air-conditioning equipment capacity, approximately equivalent to the reduced design cooling load of 25%. (8) appropriate adjustment of the cold water temperature setting of the host in a host of summer air conditioning energy consumption up to the total amount of electricity the hotel 55 percent. Properly adjust the set temperature of cold water host can receive better energy saving effect.　　 Cold water temperature is higher, but the host is the lower power consumption rate. Each raise 1 ° c, power save about 3%.　　 In increased water temperature setting, subject to the load side of the temperature requirements. Increase the cooling water of the temperature in two ways: first, the cold water temperature setting with an outdoor temperature; second, the cold water temperature with thermal load settings. 3, central air conditioning systems maintenance and energy saving (1) regular maintenance of air conditioning system in each year the management ① before running the air conditioning system to suppress the check test, flushing.　　 ② System remover to clean regularly. ③ fan coil drip tray periodically check cleaning. (2) refrigeration unit powered on before the maintenance management ① check frozen water, cooling water valve switch is correct. ② Check host, oil system, refrigerant system switch is correct, the liquid level is normal.　　 ③ in check while logging frozen (cooling) water temperature and pressure difference, the host the oil level, the level of refrigerant, built-in pressure, oil temperature. ④ above check result record. (3) host operation maintenance management ① in operation during the scheduled check cooling system with and without leakage phenomenon. ② do operation records, one record per hour. Need to record with the oil temperature, oil pressure, oil, gas pressure, evaporation pressure, evaporating temperature, exhaust gas pressure, temperature, changes in the liquid level of the refrigerant, chilled water temperature and water pressure difference, the difference in temperature of cooling water pressure difference,, current, voltage. ③ check anomalies. (4) unit outage maintenance management ① close which unit to which the water leakage out machine in case of outage of thermal damage to the device. ② When you open the post frozen cooling water in and out of the water valve, guarantee the economical operation.　　 ③ unit running at one time to the evaporator, condenser, oil cooler water system thoroughly clean, otherwise it will lower the unit cooling capacity, increasing operating costs. ④ hosts the relief valve, instrument to validate every year and record at a time, to ensure the safe operation of the unit. (5) air conditioning disabled system maintenance ① system to repeated washing.　　 ② Rinse after using the constant pressure equipment enables the system to maintain a certain amount of pressure to ensure that pipe wall does not get rusty, avoid system and then run of clogging. ③ all rising stem valves all butter protect the valve stem.　　 4, energy metering monitoring and management (1) to adopt certain measures to strengthen the management of central air conditioning. Energy metering monitoring is the basis for energy management:--in the cooling and heating system, you set the temperature, pressure, flow, heat capacity, and other monitoring instruments.　　 --Power, fuel consumption, water consumption, the consumption of steam, classification, classification setReset the cumulative meter. --Disperse set air conditioner, air conditioning unit of electricity consumption, distribution system and the decentralized units, set the meter. (2) strengthen air conditioning operation personnel training, to 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; have the necessary knowledge of refrigeration and air conditioning; to know according to the outdoor adjustable parameter change; to know how to adjust the will and energy saving.