Central Chilled Water System

Chemicals for dosing the circulating water system, the service water system and the central chilled water system (antifreeze)... 

Refrigerant for the central chilled water system chillers Potential for corrosion is considered in the BCD for three potential sources ... 

The HVAC systems require chilled water as a cooling medium to satisfy the ambient air temperature requirements for the plant. The central chilled water system (VWS) supplies chilled water to the HVAC systems and is functional during reactor fiill-power and shutdown operation. 

The cross-cormections between the central chilled water system piping for containment cooling and hot water heating system piping for containment heating are located outside the containment. The water piping inside containment is common to both the central chilled water system and hot water heating system. 

FIG. 11 -69 Typical central-station air-conditioning unit and control system. On a rising room wet-bulb temperature, the wet-bulb branch-line air pressure increases through the reverse-acting outdoor-air wet-bulb temperature-limit thermostat Ti to open gradually the maximum outdoor-air damper Di and simultaneously closr return-air damper Dg, then gradually open chilled-water valve Vi- On a rising room dry-bulb temperature, the dry-bulb branch-line air... 

The chilled air of the central station system serves the purpose of providing the proportion of fresh air needed, and carrying heat energy away from the space. These functions can be separated, using a more convenient fluid for the latter. Since the heat is at a temperature well above 0°C the obvious choice of fluid is water, although brines are used for some applications. 

Water can be chilled at a central location by a dedicated refrigeration unit. Alternatively, refrigerant brine distributed as a general utility can be used to chill plant cooling water as and where necessary. After use, this water is sent to the cooling water return system. This becomes a standard application for autility, and we do not consider it further. 

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