The first part of the buying process is deciding whether you need an air cooled chiller or a water cooled chiller. Now, if you are simply replacing or upgrading an old unit, you will most likely replace that unit with the same type of chiller. However, if you are dealing with a new installation then you will need to check your options.
The two most popular types of chillers are air-cooled or water-cooled. The "air" or "water" cooling names refer to the type of condenser used by the chiller to cool the refrigerant. Air cooling is the most commonly used chiller system because it is a stand-alone system. No additional external components are required. These systems are not as efficient as water cooled chillers but are more attractive because they are self-contained. Air-cooled chillers are relatively easy to install and start up.
Water cooled chillers require an external cooling tower and cooling tower supply pump to cool the water cooled condenser. If your plant already has an existing cooling tower with excess capacity, then this is the best option for you to consider. Once you have decided on an air-cooled or water-cooled chiller, you now have to make some more difficult decisions.
Air Cooled Screw Chiller
If you are looking for a relatively small chiller (under 30 tonnes), you must buy a scroll chiller. If your cooling needs exceed 30 tonnes, you need to make a decision. Do you use a scroll compressor or a screw compressor. When comparing screw and scroll chillers, there are several things to consider when making this decision.
Scroll compressors are limited in size. Although technology is constantly improving and increasing its size, the largest scroll compressor you can buy today is 40 HP. therefore, if you need a larger cooling load, you will need multiple compressors. While this may be a benefit, you need to ensure that you do not install multiple compressors on a single circuit. Doing so could lead to future service nightmares.
Screw compressors have their own limitations. The smallest screw compressor is 30HP. however, this is where their limitations end. At the top end, we have screw compressors with over 500HP. At that size, we don't even have an air-cooled condenser large enough to accommodate it. (It can only be installed on water-cooled chillers). Screw compressors are often seen as a real industrial process option. "The right tool for the job."
Water Cooled Screw Chiller
Scroll compressors fit into a good niche market. They are well suited to smaller process applications - especially when operating times are more sporadic (< 24 hours/day). We classify our scroll units as medium sized process chillers. Scroll chillers can handle longer operating times depending on the environment.
If you plan to run your equipment 24/7 and meet the load requirements (over 30 tons), we will always recommend a screw chiller over a scroll system. Screw compressor systems offer better capacity control options, are fully available and have a wider operating range.
We hope that this overview has helped you to make the decision to purchase a new chiller or replace it. While one of our main objectives is obviously to sell and manufacture first class cooling equipment, our priority is to provide you, the customer, with enough information to make an informed and well-informed decision.
Let us help you find the type of chiller your project. When you contact us, please provide your detailed requirements. That will help us give you a valid quotation.