Experts, I have a question regarding the requirements for chilled water tanks: are there any standards specifying the minimum size that such tanks must have? Thank you so much! !

It’s sufficient to meet the process and safety requirements; arbitrary regulations without any basis are nothing but reckless actions, right?

It depends on the purpose of the chilled water. For example, when it is used to cool polymerization reactors, it is necessary to ensure that the amount of cold storage available in case of a cooling failure does not pose a risk (of course, users who are not critical must have their water supply interrupted). If such requirements do not exist, then at least a buffer capacity of 5 to 15 minutes from the water pumps is required.

The last edit to this post was made by *aoye613 on 2022-7-11 at 13:45. Generally, the following two factors need to be considered: 1. Preventing frequent startups (or preventing the temperature of the refrigerant from fluctuating beyond the set value): that is, during the time interval between when the refrigerator stops operating once it reaches the set temperature and when it is allowed to start again, the increase in the refrigerant’s temperature must not exceed the allowable maximum value. 2. The refrigerant stored in the cold equipment and pipelines can be fully recovered to the water tank. Of course, if your coolant is water and there is no need to drain it frequently, this volume can be ignored. The following is an example of the calculation for item 1, taken from the internet: In industrial cooling systems, chilled water tanks are often installed. This is one of the most prominent features that distinguish industrial cooling systems from ordinary air conditioning systems. There are three purposes for this: exhaust gas removal, maintaining a constant temperature, and rapid replenishment of water. This shows that the chilled water tank is a very important device in the system; if its design is not proper, it will cause water temperature fluctuations to exceed the specified limits, thereby affecting production. Below, the design requirements for the chilled water tank are explained from aspects such as system, control, and structure. The main task in the design of a chilled water tank is to determine its volume. The typical flow diagram of an industrial cooling system is as follows: https://img60.chem17.com/9/20170103/636190554685132448214.jpg In actual use, due to the significant variations in customer load, which can range from 0% to 100%, and with no discernible pattern in these fluctuations, this imposes higher requirements on the design of the chiller water tank. To solve this problem, we analyze and design the chilled water tank based on the most unfavorable conditions; as long as the requirements are met under those most unfavorable conditions, the entire system will meet the requirements. The most unfavorable operating condition in actual use: starting from the moment the chiller goes from unloaded to standby mode, the load reaches its maximum value of 100%. To calculate the volume V (in M3) of the designed chilled water tank, the following parameters are also required: 1. Cooling capacity Q, in KW ； 2. Interval time t1 to prevent frequent startup of the chiller, unit: MIN ； 3. Time t2 from the start-up of the chiller to 100% full load, unit: MIN ； 4. The required minimum temperature for chilled water is T3, unit:℃ ； 5. The maximum required temperature for chilled water is T4, unit:℃ ； 6. Density of water: 1000 KG/M3 ； 7. Specific heat of water: 4.187 KJ/KG·℃ 8. Safety factor N ； 9. The water temperature in the tank is the average water temperature ； Formula for calculating the volume of a chilled water tank: V*1000*（T4-T3）*4.187 = Q*(t1 + t2)*60*N. Meaning of this formula: The amount of cold storage in the chilled water tank must be such that, from the moment the chiller goes from unloaded to standby mode until it reaches 100% load, the maximum temperature of the water in the tank does not exceed the maximum allowable temperature T4 specified for chilled water. By using the conversion formula, it is possible to calculate the volume of the chilled water tank: V = Q * (t1 + t2) * 60 * N / (1000 * (T4 – T3) * 4.187). It can be seen from this formula that the interval between frequent startups of the chiller unit, t1; the time required for the chiller unit to reach 100% load after startup, t2; as well as the minimum and maximum temperatures required for the chilled water, T3 and T4, all have an impact on the volume of the chilled water tank. To help everyone determine the volume of the chilled water tank, the following table has been prepared based on the company’s design specifications: the interval time t1 between frequent startups of the chiller unit, the time t2 required for the chiller unit to reach 100% load after startup, the minimum temperature T3 and maximum temperature T4 required for the chilled water, as well as the precision required for chilled water temperature control. This table is provided for reference: https://img66.chem17.com/9/20170103/636190555710366248195.jpg Chiller units in the screw-type series require a certain volume of chilled water tank; please use this table as a guide for calculations. The above calculation results are based on the most unfavorable conditions; in actual use, the maximum load will certainly be less than the cooling capacity of the chiller unit, and the actual load is not necessarily at its maximum value. Therefore, the volume of the chilled water tank can be reduced appropriately. Based on the above explanations, I believe that the design requirements for the chilled water tank are as follows: 1. The customer needs to provide the load variation pattern (a curve showing how the load changes over time) ； 2. The customer needs to specify the required accuracy for water temperature control; there should be no excessive demands regarding this accuracy ； 3. For a system with multiple chiller units, the capacity of the chilled water tank should be determined based on the cooling capacity of the largest unit. Due to the multiple chiller systems, it is not possible for multiple units to shut down or start up at the same time. 4. If the customer does not pay particular attention to temperature requirements under unstable operating conditions, the volume of the chilled water tank can be appropriately reduced based on the aforementioned calculation results.