Four-pipe fan coil unit air conditioner refers to a fan-coil air conditioner with both cold and hot coils. Each group of coils is fed once, totaling four coils, so it is called four tubes. The two groups of water pipes are connected with cold water and hot water respectively, that is, cooling and heating can be switched at any time in the four seasons of the year, so that some rooms can supply heat while others can supply cold. Therefore, it has high standards and costs.
There is only one set of coils in the 2 pipe fan coil unit air-conditioning box, once in and once out, cold water in summer and hot water in winter. Such a system allows the entire area to supply only cold or heat at the same time. Compared with four-tube fan coil, it saves a water system, so its standard is relatively low and its cost is low.
Advantages of the 4 pipe fan coil unit system: ① The terminal equipment of each fan coil unit can freely choose the operation mode of heating or cooling at any time without mutual interference, and the served air conditioning area can independently control the temperature and other parameters; ② save energy, all energy consumption in the system can be provided according to the requirements of the terminal, unlike the three-pipe system, there is no problem of cold and heat offset.
Disadvantages of the f4 pipe fan coil unit system: ① large investment and relatively complicated operation and management; ② due to more pipelines, the system design becomes more complicated and the pipeline takes up more space. Due to these shortcomings, the use of this system is limited.
During the year-round operation, the fan coil unit air conditioning system with 4 pipe water fan coil unit system should be adopted for the fan-coil air conditioning system with frequent alternate switching of cooling and heating conditions or simultaneous use. Therefore, it is more suitable for buildings with large inner areas or buildings with high standards of air conditioning and investment permission.
For fan coil unit air conditioning systems operating all year round, when only seasonal cooling and heating conversion is required, a 2 pipe water fan coil unit system should be adopted. The practice of large-scale construction of high-rise buildings, especially high-rise hotel buildings, shows that the 2 pipe fan coil unit system can meet the air conditioning requirements of most hotels, and is also a widely used fan coil unit air conditioning water system for multi-storey or high-rise civil buildings.
