Building services engineering/Chilled water systems/Distribution

The distribution portion of a chilled water system is accomplished using several different hydraulic components together:

• piping
• pumps (pressure generation)

These components can be divided into two different areas:

• elements that provide pressure generation
• elements that are responsible for pressure losses

The designer of any chilled water system seeks to minimize pressure losses to minimize the required size of the pump. In addition the designer seeks to fully understand the operation and design of the chilled water system end-uses to appropriately size the flow of the pump. Some end-uses may not coincide at the same time, so the actual peak cooling load may be significantly less than the connected peak load.

This is the cooling load flow represented by adding up the flow rates (L/S or GPM) that are connected to the chilled water system and that could possibly be "on" at the same time.

This is the cooling load flow represented by multiplying the cooling load flows, either in individual parts or as a whole, by what is known as a diversity factor. The diversity factor for a cooling load is always less than 1.0, as it represents the likelihood of the whole system achieving a specific cooling load flow. If one expect many more days or hours where the system is likely to exceed design conditions, then the diversity factor will approach 1.0.