Jin-Hui Plastics Industrial Co., Ltd.

Simple Formula for Heat Rejection Capacity Calculation

The cooling tower suppliers have to take into account many factors such as wet bulb temperature (What is wet bulb temperature?), circulating water rate, inlet and outlet water temperature that decide the design condition for cooling tower. In other words, knowing these factors is beneficial to meet customer’s requirement. In general, customers firstly need to know the quantity and heat requirement for equipment, and then decide the refrigeration ton of cooling tower. The formula is as below:

Generally, customers need to know the quantities and heat requirement of facilities to decide the model of cooling tower. Formula to calculate heat requirement as follow:

  • T1: Inlet water temperature to equipment (℃ ℉)
  • T2: Outlet water temperature from equipment (℃ ℉)
  • m: Water flow rate (L/min))
  • Q: Heat rejection produced by equipment (Kcal/h)

Simple Formula to calculate Heat Rejection Capacity: Q= (T2-T1) x m

From above formula, we can know the demand for heat dissipation of production equipment.

Calculation of Heat Rejection Capacity and Selection of Cooling Tower

If a factory needs the cooling tower to carry out on cooling, the equipment usually include:

  1. Water cooled chiller
  2. Oil temperature heat exchanger for blow molding machine

Requirement of water cooled chiller

  • T1 Inlet water temperature to chiller: 33℃
  • T2 Outlet water temperature after heat exchange: 38℃
  • M Water flow rate for chiller: 6000 liter/h
  • Heat rejection capacity calculation: Q = (38-33)*6000= 30,000 Kcal/h

Requirement of oil temperature heat exchange for blow molding equipment

  • T1 Inlet water temperature to heat exchanger: 33℃
  • T2 Outlet water temperature after heat exchange: 36℃
  • M Water flow rate for chiller 6000 liter/hr
  • So, the total heat rejection capacity needs about 48,000 Kcal/h (18000+30000)

Heat rejection capacity calculation: Q = (36-33)*6000= 18,000 Kcal/h

So, We total need calorific capacity about 48,000 Kcal/h(18000+30000)

After knowing the heat rejection capacity, there are three ways to choose cooling tower:

Using cooling tower comparison list to find suitable cooling tower that meets the heat rejection capacity for your equipment. The customers can provide these information such as local wet but temperature, circulating water flow rate, inlet and outlet water temperature for equipment to the suppliers to choose a suitable cooling tower.

Actually, current cooling tower companies have their own cooling condition, data, and experience for the selection of tower. On final decision, it’s necessary to consider water quality, limescale Know the relationship between cooling tower and limescale?), and climate exchange which contribute to weaker cooling capacity. Therefore, the decision of cooling capacity should bigger than the information customers provide, ensuring the stable cooling capacity for equipment.

Contact Jin Hui

Jin Hui has experience in closed circuit cooling tower over 16 years and has been serving various industries for decades. We will help you to choose the optimal cooling tower based on different cooling needs and environment. Please contact Jin-Hui by +886-4-26937836 or send email: This email address is being protected from spambots. You need JavaScript enabled to view it. to us! Your equipment deserves the best service!