Tips on Choosing the Perfect Recirculating Cooler
There are many variables involved in shopping for a recirculating cooler, and finding the perfect one for your application isn't easy. While there are obvious concerns, such as temperature range and cooling capacity, there are other less-obvious factors, like construction, flow rate & pressure, pump type, warranty & support, and more.
It's important to know to be aware of all considerations so that your pump is maximally compatible with your application for years to come.
Keep it simple (but not too simple)
Many lab procurers shop for coolers with minimum concern: they look at manufacturer specifications, find the cheapest one that fits their temperature and capacity requirements, and pull the trigger. They may think they're keeping it simple... but as many buyers eventually discover, this is a suboptimum selection strategy.
The problem with this approach is that chillers & recirculating coolers are often tested in ideal conditions (rather than during real-world use). For example, some cooler manufacturers determine cooling capacity only with small amounts of fluid and only for a limited running time. This doesn't yield accurate specifications for serious laboratories that expect to operate coolers at capacity for extended periods.
Thankfully, the solution to this problem is still pretty simple, and consists of two steps:
- Add a safety buffer of 25% to your cooling capacity.
- Use insulated tubing!
This safety buffer will protect against any sub-specification performance in a realistic lab environment; just assume you need a unit with 25% more capacity than you actually need. And insulated tubing will secure your unit against environmental heat, which can negatively impact temperatures and cooling capacity.
Following those two steps will give you much more confidence in your choice of cooler. Simple, but not too simple.
Pump protection & versatility
There are two common chiller/cooler pump types: centrifugal and positive displacement. Positive displacement pumps can be further divided into gear and turbine pumps.
Centrifugal pumps are usually internally-installed within the bath tank. This style of pump facilitates external flow as well as the circulating of bath fluid. With supplied pressure of 40+ PSI, centrifugal pumps aren't sensitive to particulates.
Positive displacement pumps are externally-installed between the chiller outlet and the heat exchanger. This is ideal for user-friendly servicing. Two precautions must be taken with positive displacement pumps (whether gear or turbine): an in-line filter and a pressure relief bypass. The former will protect your displacement pump from damaging particulates, and the latter will prevent damage in the event of flow blockage.
As with choosing a chiller or cooler, it's easy to be bamboozled by official pump specifications. High-capacity chillers are often equipped with high-capacity pumps that lack the ability to refine the pressure for different tasks or scenarios. This locks the recirculating cooler into a limited application.
To guarantee versatility, find a chiller with pressure adjustment for the internal pump. With this control, an operator can change the supply pressure on-the-fly to accommodate the current application.
Steel, not plastic
A common motif across many industries is the gradual replacement of steel with plastic. Plastic is both cheaper and lighter, both key concerns for equipment manufacturers.
But plastic components can be a problem for recirculating coolers & chillers. Fluid volume and temperature fluctuation can wear down a plastic tank, making it brittle. Larger plastic tanks are especially susceptible, and may even crack under prolonged use. Plastic tubing is also weaker than its steel counterpart, its joints eroding over prolonged exposure to extreme temperatures.
A reputable manufacturer will use stainless steel internal components. This keeps the tank and tubing healthy for a much longer time.
Connectivity & monitoring
Most labs won't have an operator constantly monitoring the cooler. That's why remote monitoring is so useful: it saves the lab time by allowing the operator to safely work on other tasks.
Recirculating coolers are connected to a computer, usually a programmable logic controller, and often via RS232. It's difficult to over-estimate the usefulness of remote chiller control: it allows for easy temperature programming and makes data logging & export a breeze.
Safety is a key reason to opt for remote control. Connected coolers can output alarm warnings and can be configured for automatic shutdown. Some chillers even feature wireless connectivity to eliminate the need for unsightly or even hazardous cabling.
Power outages are a real concern for laboratories. A disconnected recirculating cooler can be a problem: even if the cooler isn't in operation at the time of outage, when power resumes its settings might be wiped.
There are two ways to prevent this problem. First, an external logic controller can save the chiller's settings. Second, a modern cooler will often have an auto-on option, which initializes it to the settings at the time of the outage. Either option can protect your lab -- and your time -- from inevitable storms and brownouts.
Uptime, not downtime
Most cooler/chiller setups are fragile, even relatively simple ones. With multiple pieces of equipment in frequent operation, the failure of any single point shuts down the entire process until the issue is resolved. This can sometimes take days!
In other words, your setup is only as reliable as its weakest unit.
Cutting corners with a chiller purchase is just as foolish as cutting corners elsewhere in your setup. A quality, reliable unit can help prevent costly downtimes.
Make sure to review the warranty and service of the brands and models you're researching. Professional brands offer on-site service and even planned maintenance to keep your recirculator operational.
If you'd like (free!) guidance or advice in choosing a chiller or cooler compatible with your application, Growing Labs here to help. In addition to offering recirculators & chillers from elite brands like JULABO, Huber, and Across International, we provide initial & ongoing support to every customer.
For free support, reach out to us at firstname.lastname@example.org or at 1-833-476-9420.