Why does the central air conditioning system must use plate heat exchanger?

Hofmann：www.hfm-phe.com


First, the fluorine - water heat exchanger in the water system air conditioning host, plays with the secondary refrigerant heat transfer effect. Generally there are three forms of heat exchanger, A. double pipe heat exchanger; B. shell and tube heat exchanger; C plate heat exchanger. A and B are generally used in large units, with small pressure loss, low water quality requirements, not easy to plug, C general used in small units, with small size, high efficiency, But the water quality requirements are also high. The water system host, must have a heat exchanger, if not the plate must also be other type.


Second, the central air-conditioning water system use a small heating boiler to make auxiliary heating, also cascade a heat exchanger, usually the plate in front of the air conditioning host which is behind the circulating water pump in the main channel. It is used for the air conditioning system water and boiler heating water (there are two circuits heating and living hot water in boiler) heated. In winter, after setting the boiler temperature, heating up water, to reach the setting temperature, let the heating cycle pump to work, and make water output to join the heat exchanger cycle, to heat backflow water in the air conditioning system. If in order to save the cost to cancel the heat exchanger, it is necessary to connect the heating furnace in parallel on the main pipe. Using in winter, the main system circulating pump and boiler subsystem heating cycle pump have to grab water, bring about the insufficient the boiler heating water flow, so the boiler cannot get heating. There is another way to cancel the heat exchanger, add a gate valve or valve on the main pipe parallel to the boiler, when heating turn off the valve, and then cancel circulating pump of the boiler, because at this time, doing this is likely to make the boiler connected in series to the air conditioning pipeline system. The small circulation pump in the furnace will suppress flow in the main system of circulating pump, only to be canceled. This situation can only be used for boiler heating without providing hot living water, otherwise due to the principle of boiler structure, as long as open air conditioning, hot living water cannot always be burned. So under the boiler auxiliary heating case, it must use the plate heat exchanger.

评论

发表评论

此博客中的热门博文

Safety Considerations for Plate Heat Exchanger Design

图片
Hofmann During the process, there are some safety considerations you should notice: 1. Design specifications. The design specifications of heat exchangers include the types of working fluid and flow, import and export temperature, working pressure and heat exchanger efficiency. Aerospace heat exchangers should also include permissible pressure drop, size and quality. 2. Overall arrangement. First you should choose the type and structure of heat exchangers, the form of fluid flow and the materials, and then choose the type of heat surface, to consider the operating temperature and pressure, etc. 3. Heat design. The thermal design of the heat exchanger includes heat transfer calculation, flow calculation and determination of size. In addition to technical performance indicators, thermal design also need heat transfer characteristics (including heat transfer characteristics, flow characteristics and structural parameters) and fluid and material thermal activity p
阅读全文

Optimization Design Method of Plate Heat Exchanger

图片
Plate Heat Exchanger 2.1 Improve heat transfer efficiency Plate heat exchanger is a wall-type heat transfer heat exchanger, hot and cold fluid are transferred through the heat exchanger plate, fluid and plates are directly in contact with each other, and the heat transfer mode is conduction and convective heat transfer. The key to improve the heat transfer efficiency is to improve the heat transfer coefficient and logarithmic mean temperature difference 。 1). Improving the heat transfer coefficient of the heat exchanger is at the same time to improve the heat and heat on both sides of the plate surface heat transfer coefficient, reduce the thermal resistance of the dirt layer, choose high thermal conductivity of the plate, reduce the thickness of the plate in order to effectively improve the heat transfer. a. Improve the surface heat transfer coefficient of the plate Since the ripple of the plate heat exchanger can make turbulence of the fluid at a small flow rate
阅读全文

The Features Of The Vertical Condenser And Shower-Type Condenser

图片
Vertical shell and tube condenser The main features of the vertical condenser are: 1)     Due to the high cooling flow and flow rate, the heat transfer coefficient is high, generally about K = 600 ~ 700 (kcal / m2? H? ℃ ). 2)     Vertical installation covers small areas, and can be installed outdoors. 3)     Cooling water flow directly and have high flow rate, so not need high water quality, the general water can be used as cooling water. 4)     Scales in pipe can be easy removed, and do not have to stop the refrigeration system work. 5)     But in the vertical condenser, the rise temperature of cooling water is generally only 2 ~ 4 ℃ , logarithmic average temperature difference is generally about 5 ~ 6 ℃ , so need much water. And because the equipment is placed in the air, the tube is susceptible to corrosion and is easier to find its leaking. Shower type condenser The main advantages of the shower-type condenser are: 1)     simple
阅读全文