Stellar’s low-charge entry

By Michael Garry, Apr 04, 2018, 15:25 5 minute reading

Its NH360 packaged units offer an ammonia charge under 1 lb/TR in a variety of industrial settings.

A version of Stellar's NH360 low-charge ammonia system

Stellar, a designer, manufacturer and installer of industrial refrigeration systems, has entered the low-charge ammonia arena with its NH360 packaged refrigeration systems that offer less than 1 lb/TR (typically 0.90 to 0.98) ammonia charge.

The company has already installed a number of these systems, including an 1,800-TR unit at a New Jersey distribution warehouse; a 450-TR unit at a New Jersey food plant; multiple units equally nearly 5,000 TR at a Chicago pharmaceuticals plant; and three 450-TR units at a food plant in Bakersfield, Calif.

Ammonia21.com was able to query Brandon France, Stellar’s director of packaged solutions about the NH360.

Ammonia21.com: How did you get the charge so low? 

Brandon France: We use a variety of technologies depending on the situation, including our patented evaporator with integrated separator and surge capacity. Using secondary refrigerants can keep the ammonia package to a compact and critical charge.

A21: What components do you use? 

BF: We use standard industry components and apply them in innovative ways to achieve low- charge solutions, which include ammonia-only, ammonia with a secondary refrigerant such as glycol or CO2 brine, or ammonia/CO2 cascade. Evaporators are typically located in the cold storage area.

A21: Are these rooftop/outside ground installations or inside? 

BF: Our packaged systems  can be installed indoors, or outdoors on the ground or rooftop when provided with an optional integrated enclosure.

A21: Are these all new plants? Any extensions? Retrofits? 

BF: Out packaged systems have been installed in a variety of applications such as in new plants, plant additions (i.e. extensions) and retrofits where a client needs to add capacity or has chosen to replace HFC units with low-charge ammonia or CO2 units.

A21: How does the equipment/installation cost compare to the cost of stick-built systems with similar TR? 

BF: Field labor is significantly reduced since the NH360 units are built out of the weather in a quality-controlled factory and tested before leaving our facility. We also see a significant savings when an integrated enclosure is provided that houses the NH360 package in lieu of a traditional machine room.

A21: How does time of installation compare? 

BF: The savings can be anywhere from two to four months, depending on the size of the project. For example:

  1. In cases where the client chooses to install the units indoors in a new facility, the NH360 packages are built concurrent with the machine room. Once the machine room floor is cured the NH360 packages can be installed. In one instance, we offloaded two skids and set them in place in about 4 hours.
  2. Packaged systems with integrated enclosures can all be set in a matter of hours with little or no interruption to the clients production at existing plants. At new plants these units can easily be delivered and set with little disruption to the project site.
  3. Units can be shipped directly to the client, requiring only offload and tie-ins to be made by the on-site contractor.

A21: How do efficiency and maintenance costs compare? 

BF: The design and components we employ are still very much an industrial grade platform. The preventative maintenance routine and energy usage are in line with those of a traditional machine room.

A21: Are you replacing any HFC units with the NH360? 

BF: Stellar has replaced several HFC units with NH360 packaged systems that utilize natural refrigerants. Recently we have seen an increased interest from prospective clients who wish to replace R22 chillers as well as systems using other HFC refrigerants with ammonia and/or CO2.

A21: What’s driving interest in it? 

BF: A few of our clients are truly interested in protecting the environment and have implemented programs on their own to phase out high GWP and ODP synthetic refrigerants. Others see refrigerants such as R22 being phased out and do not want to switch to another HFC refrigerant only to have it phased out as well. Natural refrigerants such as ammonia and CO2 offer a solution that will not be phased out in the future as the result of environmental regulations.  

On another note, mainly outside of the food and beverage industry we see a reluctance to switch to ammonia as many are worried about its safety. Our NH360 packaged systems offer the one of the lowest charges in the industry at less than 1.0/TR. When combined with secondary refrigerants such as glycol, the ammonia is isolated to the machine room or integrated skid enclosure and away from the rest of the plant and production personnel. The secondary refrigerant is then pumped through the plant.

A21: How much interest is there in low-charge packaged ammonia units in general? Is it growing? 

BF: For many of the reasons stated low-charge units are getting more and more attention at new facilities as well as existing facilities that need to add capacity and/or wish to eliminate the use of HFC refrigerants in their facilities. For clients considering ammonia, low charge is an absolute must from a regulatory and safety standpoint.

A21: How is the NH360 different from competitive low-charge packages?

BF: We offer a wide range of standard NH360 units but will also build custom units to meet our clients specific needs. The custom solutions we offer include the following:

  1. With our without enclosure
  2. Units can include secondary refrigerant pumps integral to the NH360 package.
  3. We also offer a variety of standard and custom secondary refrigerant pump packages, cooling tower pump packages, and general pump packages
  4. Our underfloor warming skids use recovered heat to warm glycol that is pumped under the floor in large freezers for underfloor warming.
  5. Cooling towers can be located above the NH360 enclosure and supported directly from the enclosure’s optional super structure. This often proves to be the most economical solution when retrofitting a plant since the roof of an existing plant is not normally designed to support the weight of the package. Modifying the roof to support the package is very disruptive to plant operations. The cost to modify the roof also often outweighs any financial advantage that would normally be derived by installing packaged equipment.

Stellar has replaced several HFC units with NH360 packaged systems that utilize natural refrigerants.”
– Brandon France, Stellar



By Michael Garry

Apr 04, 2018, 15:25




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