Water Side Economizer Control Sequence
Water Side Economizer Control Sequence
(OP)
Editorial Comment First: This is an awesome forum that I wish I came across long before today, and I'm looking forward to reading and contributing.
Questions: What is/are some of the more reliable and trouble free control sequence(s)and system piping configuration for automatically switching back and forth between free cooling mode(plate&frame in parallel with chiller)via the tower water, and mechanical cooling with a centrifugal chiller? It seems that invariably there are chiller head pressure problems when hitting the condenser with say 42 degree tower water. Is specing a chiller with head pressure control recommended, or is there other better alternatives to accomplish trouble free switching?
Questions: What is/are some of the more reliable and trouble free control sequence(s)and system piping configuration for automatically switching back and forth between free cooling mode(plate&frame in parallel with chiller)via the tower water, and mechanical cooling with a centrifugal chiller? It seems that invariably there are chiller head pressure problems when hitting the condenser with say 42 degree tower water. Is specing a chiller with head pressure control recommended, or is there other better alternatives to accomplish trouble free switching?





RE: Water Side Economizer Control Sequence
RE: Water Side Economizer Control Sequence
What is the equipment that is being cooled? You can do it with an actuated 3-way valve (ball valve is better). You can use temperature sensors that trigger 2-way isolation valves for accidental flow of cooling water into chilled water circuit and vice-versa.
RE: Water Side Economizer Control Sequence
RE: Water Side Economizer Control Sequence
Sidenote - I've been putting VFDs on all pumps, even if they're constant flow. If you compare the cost of a VFD with that of a balance valve, motor starter, misc. control devices, and the time for balancing, it makes complete sense - forget the energy savings...