Chiller Application Basics
Process 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:
- Comfort cooling
- MRI’s, CT, PET and other scanning systems
- Semi-Conductor manufacturing and test
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 an 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.
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 your 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 much 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.
Chillers 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 24/7 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 24/7 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.