Introduction to Modular Chillers

Modular chillers are a product innovation that has recently gained wide acceptance in the HVAC industry. But since they cost more than standard chillers on a per-ton basis, it might seem a unlikely that this equipment would be a very popular cooling solution. However, modular chillers offer advantages that are not available with standard chiller equipment.

These advantages can be summarized in a few points:

• Ease of Installation
• Compact footprint
• Redundancy
  

Ease of Installation

Modular chillers were originally developed as replacement chillers for existing building chiller plants. Many chillers are located in the bowels of the buildings they serve. It is often far easier to remove the existing equipment in pieces than to find a rigging path suitable to take it out of the building in one piece. Of course, this only helps if it is also possible to move the new chilling capacity into the chiller room in pieces!

Modular chillers were designed to fit through standard doors and to have a small turning radius to negotiate internal corridors without requiring demolition of existing walls.





Additionally, since these modules are light enough to ride in a freight elevator, it is usually possible to avoid crane costs for the installation project. Further cost savings are realized once the modules are in the room. Since each module has very low refrigerant volumes, the retrofit usually does not trigger codes requiring refrigerant monitoring or emergency ventilation.

Compact Footprint

In order to fit through doors and down corridors, modular chillers are designed to be extremely compact. They use highly efficient brazed plate heat exchangers to minimize their size as much as possible:



The result is a chiller plant with the smallest footprint per ton of any current option available--even if you are installing the modules in a new project instead of a retrofit.

330 ton chiller plant comparison (click for larger image)

Redundancy

With multiple, independent modules, modular chillers provide unmatched redundancy. If a single circuit is down there are always multiple other circuits operating. And providing N+1 redundancy to a modular chiller plant is far less expensive in first costs and mechanical room space than for any other chiller type. This inherent modularity allows fantastic turndown capabilities, and the part-load efficiency of a modular chiller plant is comparable with that of a large constant speed centrifugal or screw chiller.

ClimaCool Advantages

ClimaCool modular chillers were designed to take full advantage of the modular chiller design. For example, some manufacturers design their chillers for modular installation, but not modular operation. These chillers are designed with an electrical bus bar system to power all of the modules from a single power source. This may mean a slight savings at installation, but significantly degrades the redundancy advantage of this type of chiller. With a bus bar system if one chiller needs to be worked on, the entire array needs to be powered off.

ClimaCool avoids this disadvantage by powering each module independently of all the others:



Similarly, ClimaCool offers full redundancy on the water side, too, by providing isolation valves for the heat exchangers as a standard feature. Some manufacturers offer these valves as a first-cost add and they may significantly affect the chiller's footprint dimensions if added. Providing these valves as standard provides for yet another ClimaCool advantage: Easy conversion to a variable primary flow system! Modular chillers have a tight flow envelope on the brazed plate heat exchangers--each heat exchanger should essentially be considered a constant-flow device. By providing electric actuators controlled by the chiller controller on these isolation valves, the modular chiller plant can easily adjust for variable primary flow.

Another way in which ClimaCool offers advantages over other modular designs is in heat exchanger protection. Brazed-plate heat exchangers are highly efficient and very compact, but they demand very clean water to prevent clogging. All manufacturers of modular chiller equipment require straining of the system water before it enters the exchanger. Some manufacturers provide large-mesh strainers that are mounted in the headers serving the heat exchangers at each module. This approach requires an annual back-flush of the heat exchangers to clean out the debris that inevitably passes through the mesh. It also discourages proper maintenance, since the strainers are hard to get to and are therefore often ignored until clogging causes flow problems. ClimaCool takes a different approach, using small-mesh basket-type strainers outside of the headers to prevent heat exchanger fouling. This eliminates the need for annual back-flushing, and greatly eases maintenance. They also offer a deluxe 80-mesh high-capacity strainer option for especially dirty water or for systems where maintenance man-hours are limited:


Additionally, ClimaCool provides, as standard, convenient back-flush hose-bibs to allow this sort of maintenance as needed without requiring disassembly of the chiller header or taking the other modules off-line.



And, of course, ClimaCool offers chillers that comfortably exceed minimum energy code requirments:



Efficiency, redundancy, compact size and ease of installation: All reasons to consider ClimaCool modular chillers for your next chiller project.