Chiller control
A customer has a chiller bank , five 30ton two stage chillers. The load side water temp is 42*-44* summer and 52*-54* winter. What type of control and staging would be best? The load varies so staging is needed.
Here's a controller that might do the job
Techman,
Here's a link to a controller we've used a couple of times for staging control of multiple ground source heat pumps. They call them boiler controls but they can be configured for chiller operation. I don't recall whether their reset operation functions for cooling or not.
This is their control 'master'
http://www.hbxcontrols.com/products/cpu-1000.php
or this one (specifically set up for solar or geo but maybe better for you)
http://www.hbxcontrols.com/products/eco-1000.php
expansion module 'slave'
http://www.hbxcontrols.com/products/exp-0100.php
Download their PDF operating manual and read through it to see if it will do what you need. I believe you can get up to 14 stages of control total with lead lag, rotation and 1st/2nd stage compressor options. Not cheap but not too bad for commercial level.
seconded
The HBX controls are very versatile & poweful controls for heat pump applications, they do not unfortunately have an outdoor reset function for cooling yet though. If this is something you think would be useful call up Curtis there and rattle his chain, they are a relatively small and dynamic company & respond to useful suggestions.
Chiller control
The Honeywell T775 is a very flexible control-you can manage multiple stages and also have outdoor air reset. It's also very user friendly.
