Beyond Chiller Capacity
Weight, wheels and solid construction should be among the considerations when selecting a portable glycol chiller.
Generally, the factor that gets the most consideration when purchasing a chiller or any refrigeration equipment is its cooling capacity. As crucial as correctly sizing the chiller is, when purchasing a portable chiller, features other than capacity become much more important. With “portable” being a key feature, it makes sense that this type of chiller must be easy to move, simple to setup, capable of operating under many different conditions, and built to last in a harsh environment. This article will examine each of these attributes and what to look for before buying.
Portability Influenced by Wheels and Chiller Weight
The two greatest factors that contribute to a chiller’s portability are the wheel design and chiller weight. One person should be able to move a portable chiller. Upon visiting many wineries, breweries and other locations where portable chillers are used on a regular basis, it is sometimes surprising to see what is considered portable. For instance, some “portable” chillers weigh in at 500 lb and have tiny 2” casters that will not roll across the cracks in the concrete. Other “portable” chillers have four wheels all pointing the same direction, so the chiller only can be moved in a straight line. Wheels on a portable chiller must be large enough to surmount the obstacles the chiller will encounter and rated for the load the wheels will carry.
Even if the wheels are durable and properly rated for the load, if that load is more than it is practical for one person to move, the chiller is not really a portable chiller. For instance, in some process installations, there have been “portable” chillers that weigh so much when filled with glycol they cannot be moved without the aid of a forklift. Any chiller can be moved with a forklift, but that does not qualify it as portable.
Another factor that should be considered is whether the chiller can fit through a standard size door. If it cannot, its usability becomes much more limited.
Chiller Setup Includes Quick Connects
Simple setup is another important factor to consider. A portable chiller should be plug and play. Quick-connect fittings on both ends of the hose, on the chiller and on the process are a must. They will prevent the loss of glycol, eliminate the need for multiple isolation valves, and facilitate being able to move the chiller to another location quickly. Even if glycol were not relatively expensive, eliminating the mess from spilled glycol would be worth adding quick connects anyway.
Quality quick connects are worth their weight in — well, at least worth their weight in the brass or stainless steel of which they are made. Plastic quick connects can fail. If even one quick connect were to break and “dump” the reservoir during the life of the chiller, the investment in metal quick connects would have been worth it.
It may seem like an obvious requirement, but a corded electrical connection is another must. A few “portable” chillers available in the marketplace must be hard wired each time they are moved. This detracts from portability and adds to installation costs.
Another consideration is the number of connections to the chiller. Even though multiple processes may not need cooling at once, it is nice to have that option available.
Chiller Designed for Harsh Conditions
Portable chillers should be designed to operate under harsh and varying conditions. A portable chiller may be used in the morning in one part of the plant to provide 20°F (-6°C) glycol to an acid bath; then, later in the day, it is moved to provide 50°F (10°C) glycol to an air handler. When reviewing a chiller design before purchase, ask under what conditions the chiller is designed to operate, and make sure that the glycol solution is sufficient for operation at those temperatures.
Many portable chillers also have the ability to heat: Some accomplish it utilizing heat pump technology, but most of the time, heating is via a heating element. When reviewing a chiller design before purchase, make sure that the heater is a low watt density element so that high contact temperatures will not scorch the inhibitors in the glycol. Also, ask how setpoint changes are made. With a portable chiller that may be moved from process to process frequently, changing the setpoint should be as easy as pushing an arrow button up or down, or simply turning a knob. It should not require going through a complicated menu system.
Chiller Construction Designed for Frequent Moves
While quality construction is always important, a chiller that is designed to be moved on a regular basis should be constructed with materials that will hold up to the rigors of portability. Some very nice portable chillers are made without a proper housing. Machines like this work great until damaged through routine wear and tear; then, they tend to break down because they are not protected properly. Cap tubes break, condenser fins get bent, fan controls get busted off and other damage impairs overall chiller performance.
A portable chiller should have a proper housing constructed out of heavy-gauge stainless steel or painted steel, depending on the environment. Even the nicest chillers will fail quickly if they are not properly protected.
Another concern in portable chillers is the reservoir construction. In many, if not most, stationary chillers, a plastic tank is sufficient and will probably never have an issue. Because of the vibrations and jarring that portable chillers can be subjected to, a plastic tank can leak. For maximum durability, a stainless steel reservoir is a must.
Many factors and features should be considered when purchasing a portable glycol chiller, and this article only covers a few of the most important considerations. Start with selecting a portable chiller that will be easy to move, simple to setup, and have a wide operating temperature range. And, if there is one thing to know about buying a portable chiller, it is that quality is worth the investment.