Valve sizing example - 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

A 12-ton capacity R410A system has an inlet water temperature of 85°F (29°C) and an outlet water temperature of 95°F (35°C).

The manufacturer’s recommended condensing temperature is 105°F (41°C), which corresponds to a pressure of 340 psi (23.4 bar). The maximum ambient temperature is estimated at 90°F (32°C).

City water pressure is 40 psi (2.8 bar) and the manufacturer’s table gives a pressure drop through the condenser at 15 psi (1 bar). The combined pressure loss due to piping is approximately 4 psi (0.3 bar).

Use the valve sizing process to find the correctly sized valve for this application:

Procedure

  1. Find or calculate the water flow that the condenser requires. See Figure 1.
    Flow: According to the data provided, the required flow is 36 GPM (8.2 m3/h).
  2. Determine the refrigerant head pressure rise above the valve opening point. See Figure 2 and Figure 3.
    • PCLOSE: Closing point is refrigerant pressure corresponding to 90°F (32°C) = 274 psi (18.9 bar). Using a refrigerant pressure-temperature chart for the refrigerant (R410A), the refrigerant is 274 psi at 90°F (18.9 bar at 32°C).
    • POPEN: Opening point = 274 psi + 10 psi = 284 psi (18.9 bar + 0.7 bar = 19.6 bar)
    • PCOND: Condensing pressure = 340 psi (23.4 bar)
    • PRISE: Head pressure rise = 340 psi -284 psi =56 psi (23.4 bar - 19.6 bar = 3.9 bar)
  3. Determine the available water pressure to the valve. See Figure 4.
    • PIN: Inlet water pressure = 40 psi (2.8 bar)
    • ΔPCOND: Pressure drop through the condenser = 15 psi (1 bar)
    • PLOSS: Combined piping pressure loss = 4 psi (0.3 bar)
    • PAVAIL: Available water pressure to the valve = 40 psi - (15 psi + 4 psi) = 21 psi(2.8 bar - [1 bar + 0.3 bar] = 1.4 bar)
  4. Using the following data and the flowcharts, the only valve that meets all the criteria without being oversized is a 1 1/4 in. valve. See Figure 6.
    • Flow = 36 GPM (8.2 m3/h)
    • PRISE = a head pressure rise of 56 psi (3.9 bar)
    • PAVAIL = available water pressure to the valve is 21 psi (1.4 bar)