Valve sizing - PENN Controls - LIT-12011514 - V246 - Pressure Actuated Water Regulating Valve - V246 for High‐Pressure Refrigerant

V246 Series Two-Way Pressure-Actuated Water-Regulating Valves for High-Pressure Refrigerants Product Bulletin
Brand
PENN Controls
Product name
V246 for High‐Pressure Refrigerant
Document type
Product Bulletin
Document number
LIT-12011514
Revision date
2021-08-17
Language
English

About this task

Each application is unique and requires specific engineering data to correctly size and design a system to fulfill the appropriate requirements. Typically, you replace a valve with another valve of the same size in a correctly sized and engineered system.

To make a rough field estimate of the size of valve for an application, find the valve size that you need by locating a point on a flow chart that satisfies the following requirements. For the flowcharts, see Figure 1 to Figure 6.

Follow these steps, to determine the following values:

  • Water flow that the condenser needs (Flow)
  • Refrigerant head pressure rise (PRISE)
  • Available water pressure (PAVAIL)

Use the information that you obtain to locate a point on one of the flowcharts that satisfies all three steps. For the flowcharts, see Figure 1 to Figure 6.

Procedure

  1. Refer to information from the manufacturer of the condensing unit for the water flow that the condenser needs (Flow). If the manufacturer’s information is unavailable, use the following information and Figure 1 to make an approximation of water flow in gallons per minute (cubic meters per hour):

    Calculate the flow using the following values and formula:

    • System capacity (tons of refrigeration)
    • Outlet water temperature (Temp. Outlet)
    • Inlet water temperature (Temp. Inlet)
    Figure 1. Required flow

    Note: If the outlet temperature is unknown, assume it to be 10°F (6°C) above the inlet temperature.
  2. Use Figure 3 and the following steps to determine refrigerant head pressure rise above the valve opening point (PRISE):
    1. The valve closing pressure (PCLOSE) is equal to the refrigerant pressure at the highest ambient temperature that the refrigeration equipment experiences in the Off cycle. Use a pressure-temperature chart for the selected refrigerant to find this pressure.
    2. To approximate the valve opening pressure (POPEN), add approximately 10 psi (0.7 bar) to the valve closing pressure. See Figure 2.
      Note: Add about 20 psi (1.4 bar) for 3/8 in. valves.
      Figure 2. Valve opening pressure

    3. From the pressure-temperature chart for the selected refrigerant, read the refrigerant condensing pressure (PCOND), also known as the operating head pressure, that corresponds to the selected condensing temperature.
    4. Subtract the valve opening pressure from the refrigerant condensing pressure. This calculation gives the head pressure rise. See Figure 3.
      Figure 3. Refrigerant head pressure rise

  3. Use the following steps and Figure 4 to determine the available water pressure to the valve (PAVAIL). This is the actual water pressure available to force water through the valve.
    1. Determine the inlet pressure (PIN). This is the water pressure from city water mains, pumps, or other sources.
    2. Pressure drop through condenser (ΔPCOND) is the difference in water pressure between the condenser inlet and the condenser outlet. Obtain this information from the condenser manufacturer.
    3. Estimate or calculate the pressure drop through all associated piping (PLOSS).
    4. Subtract the ΔPCOND and PLOSS from PIN. The result is PAVAIL.
      Figure 4. Available water pressure

  4. Select the correct valve size from the flowcharts by locating a point on a chart that satisfies the flow, the head pressure rise above opening point, and the pressure drop across the valve.