Visit any health care facility at 3 in the morning and you will probably find that the CTs and MRs are idle, but they are not at rest. They’re still running, and in fact, they never stop running. Or more precisely, the equipment that helps keep the liquid helium liquid and the computers cool is running. Yet the chiller is a very underappreciated part of many medical systems. The name itself is a little misunderstood as well. The job of the chiller is to remove heat from a system, not to generate cold. The medium that removes the heat from MRs, proton cyclotrons, linacs and other “big iron” is plain, simple water, or more typically, a water/glycol mixture (glycol is basically an antifreeze).

With the large spike in helium prices in recent years that may continue, keeping the helium from boiling off is more important than ever, because helium losses can cost thousands of dollars a day. But the most critical contribution of the chiller is helping ensure essential medical services are not interrupted. What does it take to keep a chiller running smoothly? We asked the people who know.

Preventive maintenance is king
There’s a famous saying in the real estate business that the three most important things you need to know are: location, location, location. For chillers, it’s a little different. The three most important things are: preventive maintenance, preventive maintenance, preventive maintenance. That was the universal opinion of those interviewed for this report.


Ronnie Taylor, president of SRS, Inc./ SVSR, Inc., says, “we recommend that any chiller has at least two PMs a year.” And that was the consensus view, with many people saying that, ideally, quarterly PMs were best. In some cases, where the MR is working full time, if not overtime, monthly PMs could be in order.

Martin King, CEO of Legacy Chillers, says that having a clear maintenance plan is one thing, but “the trick is to keep the schedule of PMs you’ve set up. Don’t let it slip. If you miss a PM, that’s when trouble can start brewing.”

According to Jim Nestel, manager of projects and installations, Hitachi Medical Systems America, here’s what you should ask the service technician doing your PM to do:

• Clean the condenser coils to maintain maximum air flow for cooling.
• Check all fluid levels.
• Check fluid quality, such as glycol concentration or pH level, to verify they are in specification.
• Check refrigerant pressures and operating temperatures.
• Check all current draws.
• Perform a visual inspection for any leaks as well as worn or discolored parts.
• Perform an audible inspection for any sounds that may indicate loose parts or failing bearings.

This list of PM “to-dos” hasn’t changed much over the years, because according to Andy Wylde, president of Chiller City, “health care chillers mostly use 40-year-old technology, even if they use newer refrigerants.”


Good help is hard to find
Nestel’s service checklist is all the more important because several people interviewed bemoaned the lack of qualified personnel who understand how to work on chillers. As King put it, “one thing that’s underreported is that there’s a shortage of good technicians. That’s just a fact of life today. ”A big part of the problem, as King sees it, “is that there just are not enough young people getting into the business these days.” Taylor was quite emphatic when he said, “There are people in our industry that do not do the job, do not do a thorough job, and it causes all kinds of problems for the end user.”

What’s the answer? The short answer for the short-term is to first realize that “the medical industry has unique chillers, very niche-type products. You don’t want someone who just knows air conditioning equipment working on your chiller, but that’s what happens sometimes,” says Don McCormack, CEO of SouthWest Medical Resources. “Make sure you use the right type of person. You want a commercial/mechanical industrial contractor, a real HVAC person. And always ask for references.”

One way to find qualified service is to Google your local HVAC wholesaler, the place where industrial contractors go to buy the parts. “Call the wholesaler and say, ‘Who do you sell parts to for maintenance? Who knows how to work on chillers?’ You’re likely to get an honest opinion. That’s what we do. Opening the phone book is a waste of time,” says King.

Buy the system chiller, or go a la carte?
Whether you need a chiller for your MR, laser, linac or other piece of equipment, you always have options on what you buy. The chiller is an add-on to the system, and the system OEM will recommend a chiller that matches the equipment’s cooling needs. John Metellus, MR product manager for Siemens, says, “The chillers we recommend go thru rigorous specification and functional tests, to help predict future performance before offered in our price books, so we are confident there won’t be compatibility issues with the scanner.”

However, Siemens also outlines the technical specifications such as water flow, the heat load capacity, etc., in their system Planning Guide, so customers can make their own purchasing decisions for water cooling. Metellus says over the years Siemens has worked with “KKT Chillers, Dimplex Thermal Solutions, Filtrine, Arctic Chill and many others. They’ve all been good partners.”

Nestel of Hitachi says, “I would say 90-95 percent-plus go with the chiller we offer as an option with the system.” Virtually all MRs have their own dedicated chiller. But there are a few exceptions. Nestel notes, “Some people do run multiple machines off one large cooling source, like a big water tower on the roof. But we don’t recommend that for an obvious reason: if you have a problem with your tower, suddenly you’ve got a whole mess of problems on your hands.” “I’ve seen Duke University Hospital do that, run everything off one big main cooling tower, the air conditioning, the MRs and everything,” says Taylor, “but I don’t recommend that mainly because the MRs and coldhead get neglected.”

Water-cooled or air-cooled?
It is well known in the industry that about 80 percent of the chillers used in health care are air-cooled chillers, and 20 percent are water-cooled. Installation issues are a major reason air-cooled chillers dominate. “Air-cooled chillers can go just about anywhere. They can go outdoors on the roof or at grade level, where there’s plenty of space.

The majority of chillers are air-cooled packaged systems, where everything is in one cabinet, nice and neat,” notes Turner Hansel, vice president of sales for Filtrine. Water-cooled chillers need to be connected to the facility’s cold water system, which complicates installation and adds to the cost. Air-cooled chillers can stand alone. “A lot of hospitals don’t have room for an indoor water-cooled chiller,” notes Hansel. They also require more ongoing regular maintenance. While air-cooled chillers typically cost a little more to buy, the total cost of ownership is lower over the long run.


Redundancy and backup
Since chillers are vital components of imaging equipment, it makes sense to think about the benefits of redundancy and backup systems. Tony Trumblee, medical account manager at Dimplex Thermal Solutions, says Dimplex is one company that believes in complete redundancy. “To us, redundancy means having dual refrigeration circuits, so we have twice the capacity the MR needs. We have two compressors, two pumps, two heat exchangers. If one cooling circuit goes down, the MR can run on our second cooling circuit.”

All this redundancy, of course, comes with a cost. “Having two of everything doesn’t mean twice the price, but somewhere in the range of one-and-a-half times the price,” according to Trumblee. Hansel of Filtrine claims their chillers ensure “99.9 percent uptime,” through proprietary features. Nestel of Hitachi says redundancy is the customer’s choice. “We don’t see a lot of people opting for total redundancy, so downtime is not that big a problem, as far as we can see,” he says. “For instance, we don’t see a lot of facilities with chillers on their backup power grid. The life-critical equipment, yes, but the chiller, no. So if you have a fully redundant chiller that’s not on backup power, where does that leave you?”

The use of “city water,” from the local system, is a stopgap solution should a chiller go down. The water your typical chiller puts out is not all that cold. It’s around 48 degrees F, but it can be 70 degrees or more. The water that comes out of your tap is typically around 55 degrees F, so for a short period of time, that is good enough. “City water is a stopgap option that helps prevent boil off, but you can’t operate the machine as a scanner,” Hansel notes. A simple bypass valve on the MR lets you switch from chiller water to city water.


Remote monitoring and cybersecurity
Remote monitoring is a major trend in health care for all medical equipment, including chillers. “We’re installing a lot of remote alarm systems now,” says Taylor. “It has become a big part of our business.” That monitoring is, to a large degree, local, and runs on a facility’s subnet. It means the in-house technician doesn’t have to go on the roof or back behind the building where the chiller is located, but can see performance data and get alerts on his computer.

SouthWest Medical Resources, whose core business is not chillers, but is servicing MRs and CTs, has found chiller problems to be such a big part of downtime issues that it is working with a local chiller OEM to create a replacement chiller that provides full remote monitoring functions to help improve uptime. “We’re not selling this chiller wholesale, it’s just for our customers, as a replacement for their existing chiller,” says Mc- Cormack. “The idea we’re working on is to create a much more serviceable chiller that’s more user-friendly because it monitors its own vital functions, and makes that information readily available to the facility’s technicians and our technicians.”

Metellus of Siemens says, “The Siemens Uptime Center has the Guardian Program, for remote monitoring of critical aspects of the MRI system. You can subscribe to this optional service allowing Siemens to remotely read environmental conditions such as component (RF, gradients, and magnet cold head) cooling and temperature fluctuations which can be an indicator of water cooling performance.”

If Siemens sees something abnormal, it can proactively send a service call to address the situation. One of the challenges with remote monitoring from beyond the hospital’s own four walls is the fear of cyber attacks and unwanted network access. “With cybersecurity issues rampant these days, some hospital IT departments don’t want people from the outside to have access inside the hospital network,” Metellus says. “We have a VPN, or virtual private network. It’s secure, with encryption to add a level of comfort and ease concerns of the IT department.”

One option is to provide the chiller service company with remote data through a system that allows outbound emails only. There are similar setups that can send texts to a cell phone, but this can create a monthly cell phone bill.


Predictive service and predictive maintenance
Anyone who owns a car knows about the dreaded “check engine light,” which indicates that you’d better get service soon because something bad is about to happen. This is a predictive service scenario, and something like it is already happening in the chiller business. Some machines have an on-board data analyzer, and if operating parameters are trending in a bad direction, its “check engine light” comes on, and it will send an email saying not only that it needs maintenance, but why it needs maintenance. In an ideal world, any machine would get service when it’s needed, and before a shutdown occurs.

Predictive maintenance is akin to actuarial studies done in the insurance industry. “We base it all on actual and/or projected operating hours,” says King. “Basically, any chiller that has reached 1,500 operating hours needs a PM. ”If they know an MR is a workhorse, so is the chiller, and they can plan on being at that site every two months. If it’s doing light duty, sometimes doing a PM just once a year is enough. In the new field of predictive maintenance, King admits, “there are companies out there doing a heck of a better job than we are.”

In the near future, look for forward-thinking chiller manufactures to offer enhanced remote monitoring, predictive maintenance and service capacities as optional and standard features.