Chiller Application Basics
Chillers are basically air conditioners for fluids.
As air conditioners do, chillers move heat (BTU's) from one
place to another. If properly designed and applied, chillers
have proven to be very effective for cooling many process
applications.
Here are just a few applications for process chillers:
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Comfort cooling
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MRI's, CT, PET and other scanning systems.
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Semi-Conductor manufacturing and test
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Lasers
Basic Chiller Terminology
Below, you will find a few of the most common terms used in the
process chiller industry. Knowing what these mean can save you a
lot of time when shopping for a chiller.
Chiller Application Types
The following two application types describe how the chiller
rejects heat (BTU's) is has absorbed from your process.
Air Cooled Condenser: In the case of a air-cooled
chiller application, heat is rejected, using fans built into the
chiller, to the surrounding air. Air-cooled chillers, are the
most commonly used for applications requiring two hundred tons
of cooling or less.
Water-Cooled Condenser: In the case of an water-cooled
chiller application, heat is rejected to another water source.
This is commonly an evaporative cooling system such as a cooling
tower. Water-cooling chiller systems are most common for larger
tonnage applications from two hundred tons and over.
Chiller System Configurations
Within the above application types, you will find two
system configuration types on the market.
Package Chiller: Refers to all of the chillers major
refrigeration components being located within one unitary
cabinet. Package configurations are the most common because of
their ease of installation and lower overall cost. Package
applications are common for both water-cooled and air-cooled
application types.
Split Chiller: This configuration type refers to some
portion of the chiller system being remote mounted such as an
air-cooled condenser. Split chiller systems can offer some
advantages when weight or space are a concern. In most
cases, split chiller configurations tend to be of an air-cooled
type.
Thermal Storage
Legacy offers chiller systems with and without integrated tank
technology. There are two common chiller operating environments
where an integrated or external tank is recommended. First, if
your process load tends to vary more than 20% and your load
requires stable fluid approach temps. Second, to prevent short
cycling of your chiller refrigeration system you should have a
minimum system volume of THREE TIMES you process flow. For
example, if you have a design flow rate of 100 GPM, you will need
about 300 US gallons of volume in your system.
Chillers Operational Classifications
When a buyer is tasked to purchase a chiller, it is important to
understand three different Chiller Operational Classifications. Each of
these classes, is designated by how the chillers is applied to
the process load.
Mission Critical: Process requires cooling 27/7 with the
potential for significant loss of income if the chiller were to
go off line unexpectedly. Chillers deployed for Mission Critical
applications tend to be of industrial grade, multi stage design
with a backup cooling system such as City Water Bypass.
Legacy manufactures several Mission Critical Class chiller
systems.
Standard Design: Process does not require 27/4 cooling.
An unexpected chiller shutdown, although inconvenient, tends to
not represent a significant impact on the end users operations.
When buying a chiller for a business application Legacy
recommends looking down the road a bit at potential future
needs. In many cases purchasing a Mission Critical class chiller
is a better long term investment.
Seasonal: Process chiller is not used every day.
Shutdowns have no dramatic detrimental impact on the users
business.
Five Rules to Purchasing a chiller
Rule 1 - What are you cooling?: Spending time looking
close at what you plan to cool with you new chiller. If you are
cooling equipment that is manufactured by someone else such as
an MRI, CT scanner or Semi-Conductor tester, look through the
manufactures site preparation documents then ask the manufacture
to verify you estimates. We also recommend that you spend time
considering the growth of your business. In many cases, you can
double the capacity or pumping capability of the chiller for
muc less than you would think.
Rule 2 - Know your Chiller Classification: Make sure you
look over the "Chiller Operational Classifications" above and
make sure you select a chiller class that meets or even exceeds
your current needs. Spending a little more in the short term can
pay significant dividends in the future.
Rule 3 - Get design help: By all means! Find an
expert that is willing to help you. If your business does not
have an in-house designer Legacy can help. We offer several low
or no cost design tools for our customers. If you need more
in-depth chiller system assistance, Legacy offers competitive
design rates that can be rolled into your next chiller purchase.
Rule 4 - Price vs Cost: Realizing this is an over done
"Sales-ee" sounding term, it does still have some merit when
looking at a long term capitol investment such as a chiller.
Legacy recommends that you look at your amortized costs over
time to zero in on the best investment. Assuming you maintain
your equipment, your chiller should last at least 15-18 years.
Considering how long you will live with this investment
decision, more times than not upgrading to the next class or
increasing to a larger pump results in only a few additional
dollars per month.
Rule 5 - Learn what's in the box: Educate yourself. If
you are not familiar with chillers, call us or check out our
Knowledgebase system to learn as much as you can before making
your purchase. If you are in the market for a chiller, Legacy's
Quote Wizard system has some great features that provide
detailed information on chillers and options as you proceed
through the quote process.
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