Weak current college】 【more online features of air conditioning systems, as well as the design and analysis.

<br> <br> Several online known as the "multi-split" refers to one outdoor unit through the pipe connection of two or two above indoor, outdoor side air cooled heat exchanger forms, interior side with direct evaporation in form of an air .conditioning system refrigerant. Many online system at present in small and medium-sized building and part of the public buildings in an increasingly wide range of applications. <br> <br> First, many features of the online system <br> <br> .Number of online and traditional central air-conditioning system, has the following characteristics: <br> <br> ① to conserve energy, low running cost. <br> ② occupied space savings. <br> ③ control advanced, reliable running, convenient .maintenance. <br> ④ Unit good adaptability, refrigeration and heating temperature range. <br> ⑤ No juice freedom, easy to install and billing. <br> <br> Second, many online technology <br> <br> More online in .order to achieve energy-saving purposes, through the refrigerant flow of effective control of compressor and variable capacity. At present, more mature technology in two ways: one is frequency online technology in the second category is the digital scroll technology, more online <br .> <br> (1) frequency more online (VRV) technology refers to single-line multi-split air stream heat pump system with adjustable output capacity outside the host: <br> <br> ① by changing the input number of compressor to .adjust the capacity of the host, host capacity of coarse adjustment. <br> <br> ② changes via frequency converter input frequency inverter compressor to alter the compressor speed, host of fine adjustment of capacity. By weight, and can make outdoor host output .capacity continuous linear regulator. Frequency of multiple online manufacturers mainly concentrated in Japan, Toshiba, Daikin, Hitachi, Mitsubishi, and so several well-known brands. Domestic manufacturers generally is collaborating with production, such as Haier, Hisense and Hitachi, etc. < .br> <br> (2) digital scroll technology a unique performance called "axial flexibility." This performance allows fixed scroll up along axis can be a very small amount of movement, to ensure the best ability to scroll up and fixed Orbiter is always .loaded together. In the operating conditions the scroll-up collection with the best power ensures digital scroll technology, high efficiency. <br> <br> Piston installed at the top of the scroll-up fixed to ensure that the Pistons move up the top .scroll up while also move up. At the top of the piston of a Chamber, through the vent 0.6mm diameter and exhaust pressure connected through an external electromagnetic valve connection Chamber and inspiratory pressure. Solenoid valves are normally closed position, the Pistons up and down .the side of pressure exhaust pressure, the spring force to ensure that two scroll up a total of earthworm loaded. Solenoid valve power to regulate indoor exhaust is released to the low pressure suction pipe. This leads to the top of the piston moves, with the .scroll wheel to move the action above separated two scroll up, causing no refrigerant mass flow rate through the scroll wheel. External electromagnetic valve off external electromagnetic valve compressor off again, restore full compression operation. <br> <br> Digital scroll operation in two .stages: the status of the "load", when the solenoid valve normally closed: "uninstalled", when the solenoid valve to open. Load status, compressor like regular work as a scroll compressor, passing all the capacity and the flow of refrigerant fluids .. However, unloaded state without capacity and refrigerant mass flow rate through the compressor. By compressor periodically to load a uninstall variable capacity refrigerant control, digital scroll compressor, foreign companies as the main United States Copeland manufacturers in China to co-operate with Samsung, .beautiful, gree, etc. brand represents. <br> <br> VRV frequency more online and digital scroll multiple online comparison has the following their respective characteristics: <br> <br> (1) capacity output: inverter compressor operating frequency range 30 .Hz level to 117 Hz, adjustable in the range of 50 per cent of a 130 per cent capacity output is ongoing. When the load mutations, the increasing frequency of the compressor requires a transitional period in question. Capacity output cannot respond immediately, digital scroll .output at 10 per cent to 100 per cent. By changing the load ratio enables continuous capacity output, this indoor more accurate temperature control, and more energy efficient. <br> <br> (2) energy efficiency ratio: frequency inverter multi online system .losses accounted for approximately 15% of power consumption, thereby reducing the system's COP. Frequency range online capacity, reduces the system load narrow to a certain extent, frequency conversion system must use the refrigerant heat bypass for capacity adjustment, since the refrigerant heat bypass, .there will be loss of energy, the system of the COP to reduce other frequency systems need to inject a large amount of lubricant, making the system COP lower digital scroll multiple online no energy loss of frequency converters and do not require heat bypass, so no .hot air by-pass losses 10 per cent (for unloaded state motor is still in the works, about 10 percent of the energy loss) to 100% load, good performance COP. <br> <br> (3) concave oil performance: .frequency more online at low load, lower refrigerant flow back into the oil system generally no difficulty, including the oil separator and return oil circulation. This is the larger capacity of the outdoor unit is more obvious, as the return gas pipe diameter is large, .in part load conditions next gas speed is very low. Therefore, the need for more frequent oil circulation and consumes more power. Outdoor unit of PCB and pipeline is complex, system stability. Digital scroll more online at each cycle, and full-load operation .of seconds, so the oil is good. At no-load, no exhaust compressor, so that there is no oil discharged, the outdoor unit of PCB and pipeline and frequency multi system is extremely simple in comparison to (no by-pass loop) ., a PCB is sufficient, and system stability. <br> <br> (4) dehumidification of: frequency more online at low load state run, cooling capacity reduction, dehumidifying performance decreased significantly, digital scroll multiple online in thousand what load conditions, .can maintain a lower average inspiratory pressure and evaporating temperature, fierce and can provide a very good moisture resistance, particularly in low-load operation. <br> <br> (5) on the other not interference by: frequency online because of the frequency .means Yuan Festival capacity, in a slow frequency will produce electromagnetic interference and higher harmonicWave, precision instruments and electronic devices. Because of the digital scroll is instantly loaded and instant uninstall works. makes current dramatic changes occur blink asked, on power system and power system .didn't impact by will. So from a technical perspective, the frequency of multiple online and digital scroll multiple online each have advantages and complementary strengths and weaknesses. <br> <br> Third, many online system design problems <br> <br .> Within the machine capacity and 3.1 outside machine capacity of matching <br> <br> Outdoor capacity match than should be under the system of the indoor unit at the same time usage, the indoor unit is located in room asked cooling load and thermal load .when asked distribution of peaks, etc. For large public buildings such as the air conditioning system, it is recommended that you protect the system to run safety-ratio should not be more than 110 percent. For more online system for household use, in the .protection system operation safety-ratio can be increased to 130%. <br> <br> 3.2 cooling capacity correction <br> <br> Because the pipeline extension after the refrigerant frictional resistance loss increment, Flash, end indoor refrigeration / system efficiency. .In addition, the line is too long for VRV systems, part of the lubricating oil is deposited in the refrigerant piping, causing long-term running back to oil for lubricating oil. Many online air conditioning system for indoor and outdoor machine rated cooling capacity is .in standard conditions measured data, actual engineering conditions often deviation increase, therefore, product samples provided by the technical parameters and the actual engineering conditions (indoor and outdoor temperature, both inside and outside the machine height difference, pipe length), deal with the cold ., otherwise to use requirements. <br> <br> 3.3 outdoor collection <br> <br> Relative to the traditional central air-system, many online system closer to the room air conditioner. Fresh air than conventional central air-system easy to .do, now commonly used fresh air mode with the following children: <br> <br> (1) indoor unit as a new fan for fresh air, untreated fresh direct access indoor unit, indoor air load was part of the burden, indoor models ., noise increases, the outdoor temperature is high, makes outdoor Captain asked overload, over current protection. And in outdoor air humidity is large, indoor dehumidification capacity increase, the indoor relative humidity cannot guarantee that requirements. <br> <br> (2 .) using a dedicated new fan. These new fans are usually designed by fresh State, increased the unit number of the row of coils, fresh air into the room status points. But this means higher construction cost and affect the application in the project. On .the other hand, the outdoor temperature is high, the compressor is not asked to break a long time to run, affect the life of the unit. <br> <br> (3) total heat exchanger with fresh air. Use the full- .heat exchanger in the fresh air from the room supplement, the use of the indoor air of chilling to cooling of fresh outdoor air, reduces the load, very energy-saving, this approach is suitable for a exhaust requirements. But you need to be aware .of new air inlet and outlet of the layout must be reasonable, the system is complex, and there is fresh air and exhaust cross contamination problems. <br> <br> The design should be based on the above characteristics and reasonable choice of fresh approach .<br> <br> IV. Summary <br> <br> In recent years, the domestic small and medium-sized central air conditioning, especially with multiple online market development is very fast. With the DVM system continues to increase, many online .application in large-scale project has become a trend, and have begun to encroach on chillers market territory, over the next few years will shape the online consumer. The future of the air conditioner market, many online will play an increasingly important role. < .br> <br> <br> <br>.