HRSH250-A Required Cooling Capacity Calculation Example 3: When there is no heat generation, and when cooling the object below a certain temperature and period of time. Heat quantity by cooled substance (per unit time) Q : Unknown [W] ([J/s]) Cooled substance : Water Cooled substance mass m : (= ρ x V) [kg] Cooled substance density ρ : 1 [kg/L] Cooled substance total volume V : 300 [L] Cooled substance specific heat C : 4.186 x 103 [J/(kg・K)] Cooled substance temperature when cooling begins T0 : 305 [K] (32 [°C]) Cooled substance temperature after t hour Tt : 293 [K] (20 [°C]) Cooling temperature difference iT : 12 [K] (= T0 . Tt) Cooling time it : 900 [s] (= 15 [min]) * Refer to the following for the typical physical property values by circulating fluid. Q = = = = 16744 [J/s] . 16.7 [kW] Cooling capacity = Considering a safety factor of 20%, 16.7 [kW] x 1.2 = m x C x (T0 . Tt) it ρ x V x C x iT it 1 x 300 x 4.186 x 103 x 12 900 20 [kW] Precautions on Cooling Capacity Calculation 1. Heating capacity When the circulating fluid temperature is set above room temperature, it needs to be heated by the thermo-chiller. The heating capacity depends on the circulating fluid temperature. Consider the radiation rate and heat capacity of the user’s equipment and check beforehand if the required heating capacity is provided. 2. Pump capacity Circulating fluid flow rate varies depending on the circulating fluid discharge pressure. Consider the installation height difference between the thermo-chiller and the user’s equipment, and the piping resistance such as circulating fluid pipings, or piping size, or piping curves in the machine. Check beforehand if the required flow is achieved, using the pump capacity curves. Circulating fluid discharge pressure has the possibility to increase up to the maximum pressure in the pump capacity curves. Check beforehand if the circulating fluid pipings or circulating fluid circuit of the user’s equipment are fully durable against this pressure. Circulating Fluid Typical Physical Property Values 1. This catalog uses the following values for density and specific heat in calculating the required cooling capacity. Density ρ: 1 [kg/L] (or, using conventional unit system, weight volume ratio �､ = 1 [kgf/L] ) Specific heat C: 4.19 x 103 [J/(kg・K)] (or, using conventional unit system, 1 x 103 [cal/(kgf・°C)]) 2. Values for density and specific heat change slightly according to temperature shown below. Use this as a reference. Water Physical property value Temperature Density ρ [kg/L] Specific heat C [J/(kg・K)] Conventional unit system Weight volume ratio �､ [kgf/L] Specific heat C [cal/(kgf・°C)] 5°C 1.00 4.2 x 103 1.00 1 x 103 10°C 1.00 4.19 x 103 1.00 1 x 103 15°C 1.00 4.19 x 103 1.00 1 x 103 20°C 1.00 4.18 x 103 1.00 1 x 103 25°C 1.00 4.18 x 103 1.00 1 x 103 30°C 1.00 4.18 x 103 1.00 1 x 103 35°C 0.99 4.18 x 103 0.99 1 x 103 40°C 0.99 4.18 x 103 0.99 1 x 103 15% Ethylene Glycol Aqueous Solution Physical property value Temperature Density ρ [kg/L] Specific heat C [J/(kg・K)] Conventional unit system Weight volume ratio �､ [kgf/L] Specific heat C [cal/(kgf・°C)] 5°C 1.02 3.91 x 103 1.02 0.93 x 103 10°C 1.02 3.91 x 103 1.02 0.93 x 103 15°C 1.02 3.91 x 103 1.02 0.93 x 103 20°C 1.01 3.91 x 103 1.01 0.93 x 103 25°C 1.01 3.91 x 103 1.01 0.93 x 103 30°C 1.01 3.91 x 103 1.01 0.94 x 103 35°C 1.01 3.91 x 103 1.01 0.94 x 103 40°C 1.01 3.92 x 103 1.01 0.94 x 103 Note) The above shown are reference values. Contact circulating fluid supplier for details. Example of conventional measurement units (Reference) Heat quantity by cooled substance (per unit time) Q : Unknown [cal/h] → [W] Cooled substance : Water Cooled substance weight m : (= ρ x V) [kgf] Cooled substance weight volume ratio �､ : 1 [kgf/L] Cooled substance total volume V : 300 [L] Cooled substance specific heat C : 1.0 x 103 [cal/(kgf・°C)] Cooled substance temperature when cooling begins T0 : 32 [°C] Cooled substance temperature after t hour Tt : 20 [°C] Cooling temperature difference iT : 12 [°C] (= T0 . Tt) Cooling time it : 15 [min] Conversion factor: hours to minutes : 60 [min/h] Conversion factor: kcal/h to kW : 860 [(cal/h)/W] Q = = = . 16744 [W] = 16.7 [kW] Cooling capacity = Considering a safety factor of 20%, 16.7 [kW] x 1.2 = m x C x (T0 . Tt) it x 860 �､ x V x 60 x C x iT it x 860 1 x 300 x 60 x 1.0 x 103 x 12 15 x 860 20 [kW] Note) This is the calculated value by changing the fluid temperature only. Thus, it varies substantially depending on the water bath or piping shape. 29 Series HRSH Thermo-chiller Water bath V After 15 minutes, cool 32°C down to 20°C. 20°C Q x �ｪt: Heat capacity [kJ] A