【 Weak current College 】 balance valve application in engineering---Power By 【 China power house network 】

With the rapid development of China's national economy, the city's architectural construction scale and more, people on the requirements of the indoor environment is getting higher and higher. Especially in the construction of a commercial building gold, how to improve effective commercial area rate: guaranteed air-conditioning system's use and doesn't run the resulting increasing power and HVAC professionals are building developer issues of common concern. A, HVAC design of hydraulic system of either air conditioning or heating engineering, due to the constraints and will not be completely used reverse return system. Depending on the actual course system design, to ensure the system is the most disadvantageous end-of-use loop pressure head, all the other end of the air conditioning heating equipment-pressure head often greater than the value of the required design conditions, especially in large buildings feature a complex project, with long Cheng pipeline, terminal equipment and the resistance variation and air-conditioning end stops discrepancies large system, close to the hot and cold source-use head margin is too large, often appear flow distribution deviates from the design State, causing the hydraulic system. Flow deviation will have air conditioning and heating source proximal is too cold or heat heating does not. Not only does not guarantee that use of the function, also resulting in a waste of energy. 2. solve water imbalances approach 1, and throttle orifice in the thermal entrance or air conditioning close to cold source loop part throttle orifice on the pipe. This approach is premised on the hydraulic offset: water resistance calculation accuracy, heat or air conditioning Terminal traffic cannot be changed. So in the end you still flow change can cause hydraulic imbalance and energy waste. 2, installation manual control valve on the large air conditioning system, manual control valve adjustment processes complex, manually adjust the front valve, back-end flow will be affected. Back-end, front-end flow adjusting the flow rate will change again. So the regulate time consuming for complex systems requesting control valve door engineer experience. And once the system pressure or load changes still need to resize the hydraulic system. 3. install dynamic flow balancing valve heat or air conditioning equipment on the end of the design flow, depending on the flow and pressure valve range selected balance valve, install the set of valves can be used. As long as the valve pressure difference at the changes in the design of the hydraulic pressure range, without any adjustment. III. characteristics of dynamic balance valve, balance valve 1 works: by changing the balance valve spool of flow area to accommodate valve before, so as to achieve the purpose of the control flow. Dynamic balancing valve is a local resistance can change the throttling element, for incompressible fluid their simplified flow equation is: Q = KA (△ P) type: Q-flow through valves; K — — valve to open degree of A flow coefficient; — the core of the flow area ¡÷ P — — valve and export pressure differential because the valve to open degree, unchanging premise, K value can be ignored, so the valve's flow to maintain A constant should control (△ P) unchanged. And balanced valve by variable flow area of valve and high accuracy (± 5%) of the spring and supporting equipment. Spring pressure difference of automatic control valves bile on it shed the size of the area, so that through the valve's flow constant. 2, valve's working process: when the front and rear differential pressure balance valve is less than the minimum start pressure differential is the spring is not compressed, the largest circulation area. When the valve and pressure difference in scope when the valve into the bile compression spring, work status, the water flow through the valve with the two sides of the hole and geometry of channel flow; as the valve movement, both in bile geometry flow type of channel and therefore change — body circulation area is constantly changing, in this context a differential pressure flow remains constant. When the differential pressure balance valve before and beyond the scope of work is that the valve bile full compression springs, the water flow only from the valve hole both sides of the bile flow, this valve of bile becomes fixed regulator, flow and pressure difference is proportional with the differential pressure grows. Dynamic balancing valve has a certain amount of pressure range limit air conditioning terminal equipment for maximum flow, automatic constant flow characteristics in the cosmos, complex, air conditioning and heating load is constant engineering, simplifies system debugging too, and reduces debug time. Especially in the water system of different leg with balancing valve, you can easily achieve the hydraulic balance and meet the design requirements of the environmental temperature and the air conditioning system can run in the terminal equipment is not subject to the other end of the start-up and shut-down. IV. balance valve in the practical application of engineering 1, regional heating heat balance valve entrance used to ensure the system traffic. Indoor heating systems, temperature control valves ensure each sink through the required flow, balance valve ensure a constant flow, the risers address horizontal offset. 2. air conditioning system in the large central air conditioning system, air conditioning equipment (Air processor and fan-coil) end set balance valve, through three (or two pass) electric valve guarantee equipment flow, valves for hydraulic regime regulation. In the heat and cold sources, cooling towers, pumps, etc. When designing pipelines limited. Use load balancing valve to avoid partial load, the normal operation of the equipment. 5. air conditioning system design dynamic balance valve antipathy for the attention of question 1, balance valve only plays the role of the hydraulic balance, cannot be used to load adjustment due to misunderstanding of dynamic balance valve, balance valve easy believes that can balance the air conditioning or heating load, with balancing valve to replace electric three-way valve or two way valve. But with the maintenance of structural load or indoor load (personnel, equipment, lighting, etc.) of the dynamic changes that require air-conditioning equipment provided by the dynamic changes of water also, can we as people want them to — both to ensure that the requirements of the indoor temperature, also played a role of savings. In the large air conditioning system, air conditioning equipment settings after the balancing valves; for each device affects the start and stop does not interfere with other equipment of water flow, balance valve has played the role of the hydraulic balance; electric three-way or two way valve throttle, to adjust the necessary number of environmental load. At present, with electric self control functionality of dynamic balance valves are available, press the load demand balance energy-saving air-conditioning system is easier to achieve. It uses the belt electric automation features of dynamic balance valve, you can set the waterpower balance and load regulation are combined in one, and direct traffic with computer-controlled setting, also simplifies installation and easy to install in a small space. 2. balance valve set should not be multipolarIn the air conditioning set, manual control valve is multipolar. According to this method sets the dynamic equilibrium of Multipole valve design concept is wrong. The reason for this is: If the lower level of one or more device off the electric valve, balance valve throw maintain superior flow, it may cause the subordinate was not closed device traffic increases, not only increased the flow noise, also affect the use of features, and also increases the unnecessary economic investment.
3. air conditioning design should be based on water temperaturedifference between summer and winter, backwater reasonable set of dynamic balance valve in four control air conditioning system with two balance valve can meet different winter and summer, when the water in winter and summer festival air conditioning and heating, cold water temperature, flow varies greatly, so the two control water system should be based on winter and summer different flow requirements set balance valve: method a, set the variable flow balance valve, winter and summer season when converting valves. Method two, set two balancing valve, valve 1 press winter flow select valve, valve 2 summer and winter by the biggest difference between water, winter valve selection valve 1, summer open two valve, with two valves for air conditioning equipment of four control function. Method 3, the use of dynamic equilibrium with automatic control device on computers set flow valve. Otherwise, due to winter and summer air conditioning water flow, and simple set up in the air conditioning Terminal fixed flow balance valve is not likely to meet two water balance of the season. 6. balance valve engineering design example 1, the project is located in Beijing's flourishing King new pitching well Street, DongAn market by Beijing Dongan group and Sun Hung Kai real estate development co., Ltd. joint venture to build a project, covers an area of about 21400m2. Construction scale and architectural plan is divided into A, B, C, D four district, where a, B, district as part of the new Dongan; D district as part of the dynamic city of fetch. 3rd floor, ground floor, floor 6, annex 11 of the Office as above. New Dongan frozen room total load is 10450RT (about 36750KW). Air conditioning water consists of three-layer of frozen ground floor room on the second floor to ground. In order to reduce the non-commercial area. Water system to the next available next dual-return system. On the second floor from the underground to the 20 air-conditioned tube wells. Air blower plate Tube watersystem under construction load characteristics into the outer zone, within the two loops. In the area only for frozen water, winter heating water outside the area. According to the climate and indoor meet, through building automation systems in underground layer 2 switches control the shaft power by extracellular cold-warm water, hot water switch. 2. air conditioning design balance valve programme for refrigerating units and frozen pump, to avoid for a variety of factors contribute to the occurrence of load and unbalanced load, the freezer and constant flow of secondary pump export balance valve installed on. Since the new architectural plan Dongan, and owners and architects called "fields of gold" effective commercial area rate is high, so the equipment room and cased-hole area is small, and its location is also very negative, such as the longitudinal, transverse 270m 108m across the pipeline system, the pipeline of resistance balance and system debug challenge is considerable. In order to address water system "pipeline long, difficult to balance", the design process to develop two sets of balanced programme. Programme 1: multiple sets of ordinary water pipe-well balanced valve installed in the main pipeline and ① 20 HVAC water-well balanced valve installed in the shaft exit ② location ③ balance valves installed in each air conditioning tank balance valve installed on ④ in each of the tenants of the outlet valve installed on the second plan: use dynamic balance valve ① in terminal device fan coil ② balance valve installed on the terminal device installed on air conditioning tank balance valve tested comparison, ultimately adopted balance valve was installed at the end of the air box ① balance valves and control valves within the area of retail and ② Office two or three blower fan coil pipe combined with a balanced valve and automatic control valves, the outer zone offices each fan coil for a balanced valve and control valve, balance valve 3 application of different leg ① long pipeline systems multilevel installation general balance valve price higher than the dynamic balance valve terminal device level. ② installed on the terminal device, the dynamic balance valve maintenance will affect small and start-up and shut-down of all tenants air-conditioning equipment. ③ balance valve with filter to prevent the water system pipe dirt on automatic control valve damage. ④ due balance valve in a pressure range of error of ± 5% only, some device on or off on other equipment flow almost no influence, guaranteeing the stability of water terminal units. New Dongan engineering is concerned, the duration of the project; as the tight market changes have given rise to numerous changes in project design. It works not opened immediately and debugging, although debugging work has not been fully carried out, but due to the use of dynamic balance valve, air conditioning with a floor area of 18 thousand square meters of different leg of the water system, "not-that is," does the benefit of owners. The new building features Dongan complex containing write,, computer network center, shopping malls, retail shops, restaurants, cinemas, and so on, its complex, varied architectural plan. Its architectural features cannot be relative concentration. Owners request design to do dynamic adaptation to market changes — maintaining the status quo, air-conditioning load of nature changeable, district, various types of air conditioning load times are not the same. However officially adopted the correct design and this is not affected by the interference of other air-conditioning end stops, dynamic balance valve opened at the end of the keep, making this huge flow of different leg conditioning system functioning is assured. So far not yet been found due to hydraulic offset arise "tenant complaints" from the current situation, new Dongan work involving the use of dynamic balance valve is a success.