The latest news and happenings from the Bonar Engineering team. Learn what sets us apart as the design/build specialist.

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Refrigerant Options for the Future


Air Unit Capacity

Dual Relief Valve Manifolds

Environmental Sustainability in Refrigerated Warehouses

Piston Expander-Linear Alternator

Compressor Lubrication Systems

Thermosyphon Oil Cooling Part 2

Thermosyphon Oil Cooling Part 1

Preventing Hydraulic Shock

Freezer Dock Doors

Surge Drums

Dock Levelers


Condenser Water Treatment

Preventing Ammonia Spills by Proper Design

Air Units and Hand Expansion Valves

Response to IIAR 2

Floor Expansion Joints

Freezing Systems


Desiccant Air Treatment

Comments Regarding IIAR Standard 2

Rules of Thumb for Machinery Room Design

Hank’s Rules of Thumb

Cold Storage v Dry Storage

The Truth About Oil Pots

Annular Flow

Air Changes in Refrigerated Spaces

BTUs and Refrigeration

Air Units and Pipeline Placement

Travels Through the Ukraine and Moldova

Box-in-a-Box Construction

Side Port Economizers

Ammonia Spill Cleanup Procedures

Tomato Ripening and an Article on Russian Refrigeration

A Brief History of Mechanical Refrigeration

Are All Screw Compressors Created Equal

Continuity of Vapor Barrier

Response to OSHA and a Refrigeration System

OSHA and an Ammonia Refrigeration System

Underfloor Heating Systems

Recirculated Vessel Design

Freon Rooftop Units v Central Refrigeration Systems

Critical Gas Flow



Critical Flow

Posted on Wednesday, July 8th, 2015

Borrowing from a previous publication with equations for the pressure drop of two phase flow, a method of calculating critical flow was included in the article. All designers should become familiar with this because this is what causes reverse flow, such as happened at Millard Refrigerated and several other plants that experienced low temperature evaporators […]

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Questions for EPA

Posted on Wednesday, July 8th, 2015

I was recently asked by a news journalist what questions I would ask EPA if I had the opportunity. Not to steal their thunder, but this is what I would ask. Why are closed cycle refrigeration systems regulated under OSHA? Just because ammonia is a refrigerant does not make the refrigeration cycle a process by […]

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Machinery Room Ventilation

Posted on Wednesday, July 8th, 2015

Machinery Room ventilation is the first and most important design of an ammonia machinery room. Sadly, its geometry is often determined by an architect or general contractor that only thinks cost. Machinery Room location is paramount in terms of accomplishing good ventilation. In years past some of the dairies put Machinery Rooms in basements. It […]

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Posted on Wednesday, July 8th, 2015

As a charter member of IIAR, I can witness that it has taken a long time to get model codes (IMC) to recognize ANSI-IIAR 2 as a code for ammonia refrigeration.  I can remember when Hank Saye and I worked out the 1” valve bypass arrangement, and how skillfully Jeff Shapiro planned that that would […]

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The Noble Condenser

Posted on Wednesday, July 8th, 2015

You’ve heard me say many times about condenser water: no treatment is the best treatment. I know there can be exceptions to the rule, however I bear witness to a condenser that was installed 26 years ago that is currently being retired, not particularly because it’s worn out, it just needs to be larger. The […]

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Recent Overseas Travels

Posted on Monday, June 16th, 2014

USDA – Honduras, August 2008 In August 2008, Mr. Bonar traveled with the USDA as a technical consultant to Puerto Cortes, Honduras. He inspected the port cold storage facility, and made recommendations to improve conditions and the frequent malady of “temperature abuse” in the cold storage industry. DAI – Serbia, April 2009 Mr. Bonar was […]

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Posted on Tuesday, March 1st, 1994

Over the years, we have helped develop a number of blast freezing systems. Most of these, known as “superblasts” (as in supercharge), originated from developments at Cassco, Harrisonburg, Virginia, in the early 1980’s. They were refined later at Wiscold (to then-CEO George Sayres’ credit), and have “evolved” substantially in many other facilities since. Traditional blast […]

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Posted on Tuesday, March 1st, 1994

Public refrigerated warehousing was the genesis of perishable food distribution. Prior to then, fresh or fresh frozen products were only available on a local basis. Because of the complexity of early refrigerated facilities, central major installations provided public needs with large efficient installations. Although today perishable space is shared (nearly) equally between private and public […]

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Posted on Tuesday, March 1st, 1994

We have had the recent opportunity to make visits to Russia and see firsthand what the refrigeration industry provides for perishable storage distribution. In addition to refrigerated facilities, refrigeration compressor manufacturing plants were visited. Having been a professional curiosity of Hank’s (Henry Bonar, II), the trip was indeed a rewarding experience, and one that has […]

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