How To Calculate Chilled Water Flow Rate From Kw

Chilled Water Flow Rate Equation:

\[ \text{Flow (L/s)} = \frac{Q}{\rho \times c \times \Delta T} \]

Cooling Capacity (Q):

Water Density (ρ):

kg/m³

Specific Heat (c):

kJ/kgK

Temperature Difference (ΔT):

Chilled Water Flow Rate:

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1. What is Chilled Water Flow Rate Calculation?

The chilled water flow rate calculation determines the volume flow rate of chilled water required to achieve a specific cooling capacity in HVAC systems. This calculation is essential for proper system design and operation.

2. How Does the Calculator Work?

The calculator uses the chilled water flow rate equation:

\[ \text{Flow (L/s)} = \frac{Q}{\rho \times c \times \Delta T} \]

Where:

\( Q \) — Cooling capacity (kW)
\( \rho \) — Water density (kg/m³)
\( c \) — Specific heat of water (kJ/kgK)
\( \Delta T \) — Temperature difference (K)

Explanation: The equation calculates the flow rate needed to transfer the specified cooling capacity, considering water properties and the temperature difference between supply and return lines.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation is crucial for proper pump selection, pipe sizing, heat exchanger design, and ensuring efficient system operation in HVAC and process cooling applications.

4. Using the Calculator

Tips: Enter cooling capacity in kW, water density (typically 1000 kg/m³ for water), specific heat (typically 4.186 kJ/kgK for water), and temperature difference in Kelvin. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical temperature difference (ΔT) used?
A: Typical ΔT values range from 5-10K for chilled water systems, with 5.5K being common in many HVAC applications.

Q2: Why use L/s instead of other flow units?
A: Liters per second (L/s) is commonly used in HVAC engineering for water flow rates, but the result can be converted to m³/h or gpm as needed.

Q3: How does water temperature affect density?
A: Water density decreases slightly with increasing temperature. At 5°C, density is about 1000 kg/m³, while at 20°C it's approximately 998 kg/m³.

Q4: What if I have the cooling capacity in tons of refrigeration?
A: Convert tons to kW using the conversion: 1 ton = 3.51685 kW, then use the calculator normally.

Q5: Can this calculator be used for other fluids?
A: Yes, but you must use the correct density and specific heat values for the specific fluid being used in the system.