Summary of Pump Selection Calculation | Pump Selection in HVAC | Pump Head Calculation in HVAC

Summary of the Video: pump Selection Calculation in HVAC

The video provides a comprehensive tutorial on the calculation of pump head and selection in HVAC systems, specifically focusing on primary pump circuits. The main ideas and methodologies presented are as follows:

Key Concepts and Steps:

Project Layout and Data Preparation:
- The project layout includes capacities of chillers and flow rates for each section of the piping system.
- The primary pump circuit is segregated from the main circuit for focused analysis.
flow rate Determination:
- The flow rate in the main circuit is determined, which is crucial for further calculations.
Critical Path Identification:
- The critical path is identified, which is where the head loss will be maximum.
pipe size Selection:
- A chart for closed piping systems is used to select the appropriate pipe size based on flow rates.
- Two criteria for pipe sizing are outlined:
  - For pipes 2 inches or less, the maximum velocity should not exceed 4 feet per second (fps).
  - For pipes greater than 2 inches, the maximum allowable pressure drop is 4 feet of water per 100 feet of piping.
Friction Loss Calculation:
- Friction loss values are determined for selected pipe sizes and flow rates.
- The velocity of water flow is calculated based on the intersection of flow and friction loss lines on the chart.
Head Loss Calculation:
- An Excel sheet is utilized to calculate total head loss, incorporating both pipe length and equivalent lengths of fittings.
pump Selection:
- The required horsepower (HP) for the pump is calculated using the formula:
```
                BHP = (Flow (GPM) × Head (feet) × Specific Gravity) / (3960 × Efficiency)
                
```
- Specific attention is given to the flow rate through the pump, which is identified as 125 GPM.
- A detailed method for pump selection involves using manufacturer catalogs to find suitable models based on calculated flow and head requirements.
Final pump Specifications:
- The selected pump model, impeller diameter, power requirement, and net positive suction head (NPSH) are determined.
- For the example given, the selected pump model is 3531, with an impeller diameter of 155 mm (approximately 6 inches) and a power requirement of 2 HP.

Methodology in Bullet Points:

Determine flow rates and segregate the primary pump circuit.
Identify the critical path for maximum head loss.
Select pipe size using velocity and pressure drop criteria.
Calculate friction loss and velocity for different flow rates.
Use Excel to calculate total head loss, including fittings.
Calculate required horsepower for the pump based on head loss and flow.
Use manufacturer catalogs for detailed pump selection, ensuring NPSH requirements are met.

Speakers/Sources Featured:

The video appears to be a single speaker tutorial, but specific names or credentials of the speaker are not provided in the subtitles.

This summary encapsulates the essential points discussed in the video regarding pump selection and calculations in HVAC systems, providing a structured approach for viewers to follow.

Notable Quotes

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