Design regarding the inlet and outlet temperatures of cooling water
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When designing heat exchangers that use circulating water as a cooling medium, what are the typical empirical values for the inlet and outlet temperatures of the circulating water? What is the appropriate flow rate of water inside the housing? Diameter of the circulation tube. Last edited in this post by 0536dai on 2009-2-7 16:59]
The inlet and outlet temperatures of the circulating water should be determined through process calculations. In my opinion, temperatures in the range of thirty to forty degrees are quite common, and in most cases, this water flows within the tube side of the system
Circulating water generally flows through the tube side; since it enters at normal temperature and the temperature of the fluid is usually between 50-60°C, the temperature difference for circulating water is typically 5-10°C. Of course, if the temperature of the fluid is higher, this difference can be greater. The flow velocity is generally set at 1.2-1.8 m/s; if the water flows through the shell side, this velocity is reduced by half. The diameter of the tubes depends mainly on the size of the heat exchanger, as well as on the cleanliness of the water – if the water is dirty, such as river water, a larger diameter can be used, while a smaller diameter is sufficient if the water quality is good.
It’s available in many engineering manuals; give it a look – it’s described very clearly
When I was designing it, I had no special requirements; everything was calculated based on a temperature range of 27-32 degrees
Circulating cooling water is generally designed based on summer temperatures, with an inlet water temperature of 33 degrees Celsius and an outlet water temperature of 43 degrees Celsius, resulting in a temperature difference of 10 degrees Celsius. The flow rate of circulating water is generally 1–3 m/s, and the pipe diameter can be calculated based on the flow rate and velocity.
Typically, the inlet water temperature is set at 32 degrees, while the return water temperature is set at 42 degrees, resulting in a temperature difference of 10 degrees. The pressure difference between the inlet and outlet water is designed to be 0.2 MPA.
For ordinary circulating water, the most severe operating conditions are generally taken into account during design. That is, the average temperature of the circulating water in summer; generally, the temperature increase is around 8 to 10 degrees. The cooling efficiency of the cooling tower also needs to be taken into account. The flow velocity is usually around 0.6 m/s on the shell side, while it can be higher on the tube side. The specifications and arrangement of the heat exchange tubes are determined primarily based on the cleaning methods and the cleanliness of the cooling water. If mechanical cleaning is used, the specifications of the heat exchange tubes generally need to be larger. A square arrangement is used.
The people above have already provided a very detailed explanation of the temperature rise of the cooling water, so there is no need to say more. However, our company generally keeps the temperature rise under 10°, as can be seen from the data provided by foreign companies; we should draw on their experience. As for the flow rate of the cooling water, it is usually maintained at around 0.8–1.0 on the shell side in order to increase the heat transfer coefficient. As for the flow velocity of cooling water inside the pipes, different requirements apply depending on the medium in the pipes, so it cannot be generalized. It’s generally not less than 1.5, right? Too low will affect the effect. The data on the sixth floor is worth considering.
In general, designs are based on the most severe operating conditions; therefore, summer temperatures are used as a reference. For the design I’ve developed, the inlet water temperature is typically set at 33 degrees Celsius, while the outlet water temperature is 43 degrees Celsius. (Of course, the environmental conditions also need to be taken into account, and this information can usually be obtained from the user.) The pressure drop is 0.2 MPa. If copper pipes are used, the flow velocity should be less than 1.5 m/s, around 1–1.2 m/s; for brass pipes, the flow velocity should be less than 3 m/s, around 2–2.5 m/s. The pipe diameter is determined based on the flow rate and flow velocity. Last edited by vivo1314 on 2009-2-15 17:37