How to determine cooling capacity
When selecting the appropriate chiller, it is necessary to consider not only the installation location and environment, but also a model with sufficient cooling capacity to handle the heat load generated by the equipment and workpieces.
Below are two methods for calculating heat load.
We will also explain how to interpret the chiller's cooling capacity graph after the calculation method, so please read to the end.
Table of contents
How to calculate the load
When the cooling time and temperature of the object to be cooled are known
The required cooling capacity can be calculated from the target values of how many degrees you want to cool the object to, and how long you want to cool it to. In this case, you will need to check the density of the object to be cooled.
- Q= Vs×Cs×γs×(Tb-Ta) t ・・・Formula ❷
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● Q: Load capacity [kW]
● Tb: Temperature of the object before cooling [℃]
● t: Cooling time of the object to be cooled [sec] ● Vs: Volume of the object to be cooled [m³]
● Ta: Temperature of the cooled object after cooling [℃] ● Cs: Specific heat of the cooled object [KJ/g・℃]
● γs: Density of object to be cooled [g/cm³]
Calculation example
Example: Calculate the load capacity when cooling an aluminum plate that is 730 mm wide, 920 mm long, and 20 mm thick from 34°C to 24°C in 3 minutes.
However, the specific heat (Cs) of aluminum is 0.215 [cal/g℃] and the density (γs) is 2.7 [g/cm³].
*Since 1 [cal] = 4.2 J, calculations are made using a unified unit system with specific heat: 0.215 [cal/g・℃] = 0.903 [KJ/kg・℃] and density: 2.7 [g/cm³] = 2688 [kg/m³].
From the formula, load capacity Q = (0.73 x 0.92 x 0.02) x 0.903 x 2688 (34 - 24) (3 x 60) = 1.81 [kW]
safety Expecting a rate of 20%, 1.81×1.2=2.18 [kw]
We select a chiller with a load capacity of more than 2.18 [kw] cooling capacity
↓↓↓ Use the formula to find the chiller with the required cooling capacity ↓↓↓
You can easily select a chiller by applying the formula below. Please make use of it.
When the outlet and inlet temperatures of circulating water from the load (equipment) side are known
If the outlet and inlet temperatures of circulating water flowing into the device and the flow rate of circulating water are known, the load on the device can be calculated using formula ①.
- Q: Amount of heat = m: Weight x C: Specific heat x ΔT: Temperature difference From the formula Q=γb×Lb×Cb×(Tout-Tin)×0.07...Eq.
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● Q: Load capacity [kW]Lb: circulating water flow rate [ℓ/min]
● Cb: Specific heat of circulating water [cal/g・℃] ● γb: circulating water density [g/㎤]
● Tout : Load outlet temperature [℃] ● Lb : circulating water flow rate [ℓ/min] Tout : Load outlet temperature [℃]
● Tin: Load inlet temperature [℃]
Calculation example
Example: Calculate the load capacity of the equipment when circulating water with a flow rate of 12 liters/min enters at 30°C and exits at 32°C.
However, circulating water has a specific heat (cb): 1.0 [cal/g℃] and a density (γb): 1.0 [g/cm³].
From equation ❶, load capacity Q = 1.0 × 12 × 1.0 × (32 - 30) × 0.07 = 1.68 [kW]
safety Expect a rate of 20%, 1.68×1.2=2.02 [kw]
We select a chiller with a load capacity of more than 2.02 [kw] cooling capacity
↓↓↓ Use the formula to find the chiller with the required cooling capacity ↓↓↓
You can easily select a chiller by applying the formula below. Please make use of it.
Find a chiller based on cooling capacity and circulating water temperature
We have a wide range of chillers available, so please find one that meets your requirements.
If you want to know how to read a chiller's cooling capacity graph,
cooling capacity that a chiller can exert varies depending on the set temperature of circulating water and the ambient temperature where the chiller is installed, so cooling capacity under actual usage conditions can be confirmed from the cooling capacity graph.
Example: Calculate cooling capacity of a chiller when circulating water temperature is 25°C and the ambient temperature is 25°C.
From the graph on the right, cooling capacity is calculated to be approximately 2900W (selected at frequency 60Hz).
Recommended chillers that fit the criteria in this example
Chiller
HFC alternative chiller
PCU-NE2500
PCU Series
HFC alternative
- Cooling capacity(W)*1
- 2300／2600
- Thermal capacity(W)
- 400／600
- Circulating water temperature range
- 5〜40
- Temperature control stability (℃)
- ±0.1
- circulating water rating flow rate (L/min)
- 15／15
