Water regulating valves

72 APPLICATIONS The water regulating valve, employed with condenser fed with either main or well water, keeps the condensation pressure constant at the previously set value by adjusting the water flow so as to ensure a balanced heat exchange under all conditions. At plant start-up, this adjustment is designed to allow the thermostatic valve rapidly reaches normal operating conditions and subsequently, during operations, to avoid excessive pressure increases or decreases under different flow conditions. An excessive rise of high pressure affects the refrigerating capacity of the system. On the...

73 • Water temperature at the condenser inlet: 14 °C. • Expected thermal difference: Dt = 10 °C. • Condensation temperature expected on the basis of the water/refrigerant heat exchange in the condenser: approximately 6 °C above the water temperature at the outlet, equivalent to 30 °C (with a corresponding saturation pressure) (fig. 1). • Refrigeration yield at the level of the evaporator: 18,6 kW under the following operating conditions, condensation temperature: + 30 °C; evaporation temperature: –15 °C. Thermal power to be disposed of at the level of the condenser (Table 2): 18,6 x 1,325 = 24,65...

74 When the point of intersection of pressure differential through the valve and flow range is within the area between the curves of two valves, select the valve with larger diameter. When the valve is completely closed, the pressure must be the same as the refrigerant saturation pressure at the air temperature of the place where the condenser is installed. When the valve begins to open, the pressure is about 0,2 bar above the pressure when the valve is totally closed. The pressure drop corresponding to the water flow rate specified above in the condenser/piping circuit, with the exclusion of...

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