Why not Air Condition the Chiller Plant? 2

[DDC]

Although I understand the need to economize & reduce energy consuption wherever possible it seems to me to be false economny to just blindly look at reducing energy cost.

We have a large chiller plant, 4 chillers > 1000 tons each along with associated pumps, switch gear and other equipment. I maintain we should air condition the plant to reduce maintenance costs (cleaning & painting) created by excessive condensation, dirt & trash being sucked in through vents, and to improve equipment operation. Plant is in Florida where humidity is very high & increases problems.

Are there any guidelines or studies that support my views? I have 40 years in operation & maintenance & Energy Management Systems and my instinct tells me that it would be a good idea. Perhaps I'm just wishing.

Any comments, advice or references would be appreciated.
Charlie

 

[ChasBean1]

Charlie, I agree with you on that concept for a smaller mechanical room and have made recommendation to a client to condition the space. The client's application was sweating AHUs. If you read the manufacturer's literature, however, they claimed a thermal conductivity of 0.24 BTU/hr-ft2-°F and did not mention problems with thermal breaks and sweating at the AHU seams. Based on book information, the AHUs should not have sweated with room dewpoint below some 76°F, which is extraordinarly high (although maybe not in Florida). Also, if all the cold piping and components were properly insulated with sealed vapor barriers, the condensation shouldn't occur. I've seen prematurely-rotted chilled water piping, PVC sheathing condensate catches over motor control centers, rotted AHU bases around the cooling coil drains, and stained finished ceilings below these mechanical spaces. This can all start with somebody having to step on an insulated pipe in order to reach something, nerdy engineers like me cutting insulation to tie in an ultrasonic flow meter, or valve bonnet sweating, packing leaks, or any missing insulation. Some minor wetting leads to further insulation damage and it can be a snowball effect.

It really comes down to a first cost versus operating cost issue. Would it be better to hire an insulator to go through and properly wrap all cool surfaces and shield or create walkways that prevent insulation damage, or continuously pay for the energy required to cool a space that has enormous heat loads (keep in mind the heat output from you chillers' condenser shells, unwrapped components of the steam or HW systems, transformers, motor control centers, etc.). For a large mechanical room, you might find horrible energy costs associated with conditioning the space, even to slightly reduce dewpoints.

I would recommend considering a 10-20 percent efficient filter rack for the mechanical room draw-through makeup air inlet and development of a detailed scope for re-insulation of the plant. Even if this has to be done every five years, My guess is that in Florida, you would save in air conditioning costs. -CB

 

[quark]

DDC!

I work in a pharmaceutical company and there are now concerns about maintaining quality of service area conditions. Already we started ventillating the service area where we keep air handling units with filtered air. In addition, where ever necessary, the fresh air part is being fed from a common dehumidifying unit or the area is dehumidified. Though the initial and running cost (with purely energy concerns) is more when we check hidden costs it may be ok. (employee health, quality of product and mainly getting statutory approvals)

Regards,

Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.