I.What is a water system?
Water system, that is, air conditioning uses water as refrigerant. The water system is larger than the traditional fluorine system, and it is generally used in large-scale buildings. At the same time, the opening rate is above 90% to save energy. American brands occupy a major share of the market, mainly in the commercial market.
The indoor load of the water system is all borne by the hot and cold water units, and the fan coil units in each room are connected with the hot and cold water units through pipelines, and the provided hot and cold water is used for cooling and heating.
Typical air conditioning units are mainly composed of chilled water circulation system, cooling water circulation system and main engine:
1.Chilled Water Circulation System
This part is composed of refrigeration pump, indoor fan and chilled water pipeline. The low-temperature chilled water flowing out of the main evaporator is pressurized by the chilled water pump and sent into the chilled water pipeline (outlet water), which enters the room for heat exchange. The water takes away the heat in the room, and finally returns to the main evaporator (return water). Indoor fans are used to blow air through chilled water pipes, reducing air temperature and accelerating indoor heat exchange.
2.Cooling Water Circulation Part
This part consists of cooling pump, cooling water pipeline, cooling water tower, etc. The refrigeration water circulation system will take away a lot of indoor heat energy while exchanging indoor heat. The heat energy is transferred to the cooling water through the refrigerant in the main engine, so that the temperature of the cooling water rises. The cooling pump presses the heated cooling water into the cooling tower (outlet water) to exchange heat with the atmosphere, and then sends it back to the host condenser (return water) after lowering the temperature.
3.Main Engine
The main engine is composed of compressor, evaporator, condenser and refrigerant (coolants).
II.Composition of Water System
Air Release Valve: the air in the water circulation is concentrated or automatically discharged at a local position. It is an indispensable valve in air conditioning system. Generally it is installed at the highest point and local highest point of the closed waterway system.
Check Valve: mainly used to prevent the medium from flowing backwards. Mainly installed in the outlet section of the water pump.
Filter: during the installation of air conditioning system, some dirt such as mud and sand will flow down from the water pipe, and some dirt such as rust will be produced during the long-term operation of the water system continuously. In order to prevent the pollution of heat transfer tubes of air-conditioning equipment and local blockage of the system, it is required to set up water quality treatment devices at the water inlet of important equipment such as the heat source of water chillers.
Temperature-controlled Two-way Valve Or Three-way Valve: the temperature is controlled according to the load. If the room temperature is lower than the set value in summer, the water quantity can be adjusted by adjusting or turning off the electric valve. In addition, the electric valve is interlocked with the fan power supply of the fan coil unit. When the fan coil unit stops using, the electric valve will be closed to stop water supply.
Expansion Water Tank: first, it collects the increased water volume due to the expansion of water heating volume to prevent the system from being damaged. In addition, it also plays a role of constant pressure. The joints of expansion tanks are constant pressure points. Therefore, the expansion tanks connected to different positions in the system can change the pressure distribution in the water system, which is very important for the analysis of the pressure distribution in the water system of high-rise buildings.
Water Instrument: for the convenience of debugging and operation management of air conditioning system, some necessary instruments are required in water system, including the inlet and outlet of main equipment. Generally, pressure measuring devices are required to know the pressure distribution in water system and the resistance of equipment. As well as the places where the water temperature changes. Temperature measuring devices should be set such as the inlet and outlet of cold and heat source equipment.
Water System Valves: the valves set in the water system generally have two functions: one is to regulate the water quantity in the pipe network; second, it plays the role of shut-off such as the change of cold and heat sources in different seasons, or when the equipment is overhauled, it is shut off with a valve.
