oil from the pot with just gas pressure above it. Make sure you wear an ammonia mask during this process.

LOW-CHARGE CONDENSERS

Most ammonia plants employ an evaporative condenser, which is a very efficient apparatus that keeps the condensing pressure down. Te large tube construction can result in a condenser ammonia charge of more than 100 pounds.

Baltimore Aircoil Company (BAC) Evaporative Condenser

has developed a new Trillium Series condenser that uses microchannels in place of the large tubes, reducing the ammonia charge to approximately one-fourth of what a traditional condenser of comparative capacity can.

GLYCOL-COOLED CONDENSERS

To further reduce ammonia charges, another technique is to employ plate and frame or plate and shell condensers, rather than evaporative condensers. A plate style heat exchanger will reduce the condenser charge to less than 10 pounds of ammonia versus the evaporative condenser which holds over 100 pounds.

Installing the condenser in the compressor room close to

the chiller package will reduce the high-pressure piping by 90 percent, further reducing the charge and improving system safety.

Te glycol-cooled condensers can also be used to recover up

to 100 percent of the heat rejected from the refrigeration system, which will eliminate the need for sub-floor and snow-melt heat exchangers along with their piping and instrumentation, resulting in less leak points.

It can sometimes be difficult to use all the waste heat within

the ice complex, so there has to be a way to reject the excess heat, which is typically done with a fluid cooler.

AMMONIA DISPERSION TANKS

Ammonia dispersion tanks can be installed to contain the ammonia in the event a relief valve blows or if the emergency blow off valve must be opened. Te tanks require some additional consideration such as freeze protection and calculating the release setting of the valves. Once saturated, the aqua ammonia must be safely disposed of.

PACKAGED LIMITED-CHARGED SYSTEMS

Packaged limited-charge systems, which combine both a limited-charge chiller and charge condenser along with a compressor and all the running components in a single package, are becoming quite popular. By dividing the ice plant into two or three limited charge ammonia packages, it offers many advantages. Te ammonia charge

14 SPRING 2018

on each package is much less than 100 pounds. Te compact construction with minimal piping and fittings greatly reduces the potential for leaks. Te multiple chiller packages provide an elevated level of redundancy in that there are separate chillers, condensers, compressors, refrigerant and running components. Being that the limited-charged packages have fluid-cooled condensers, they are already prepared to provide 100 percent energy recovery for use in the facility.

SELF-CONTAINED OUTDOOR MACHINE ROOM

A self-contained machine room separate from the public facility prevents ammonia from entering the public space in the event of a larger leak.

It is constructed in a limited-charge format, which reduces

the ammonia charge to less than 20 percent of a traditional ammonia system. It has all the safety features that are required for an indoor machine room but also offer the advantage of having full opening doors at each end for added safety and rapid egress in the event of an emergency.

A self-contained machine room also offers many added

advantages. It is manufactured off-site which minimizes on-site disruptions during the construction phase, and the systems can be connected and started within two to three days of arrival.

Removing the refrigeration equipment from the ice rink frees

up valuable space, which can be reallocated for other purposes, such as an extra dressing room.

OPERATOR EDUCATION

It was brought up that many locations in North America do not have mandatory or recognized operator training programs. It was also discussed that in the past there has been a disconnect between what has been taught in operator classes versus what is needed in the facility versus what was being tested for in the government examinations.

It was generally felt by all parties attending the symposium

that work is needed in this area to ensure that all operators are getting the correct information that will result in safer facilities.

Every operator in a facility must:

• Know the significance of each ammonia level as displayed on the ammonia detectors.

• Develop safety procedures to isolate every part of the system, ensure that the correct valves are tagged and that operators know the location of all valves. Review the procedures on a yearly basis.

• Discern when to evacuate the building, understand the evacuation plan and be able to implement it.

• Understand which ammonia breathing apparatus is to be used during service and emergency situations.

• Realize where all the safety equipment is located, such as ammonia detectors, gas masks, eye wash stations, emergency showers and fan switch locations.

• Recognize the purpose of the emergency ammonia release