Two refrigeration contractors were facing different challenges. In one situation, a restaurant in New York City needed to add refrigeration capacity for walk-in freezers and coolers, but in a constrained space. In another instance, a chain of restaurants was dealing with aging refrigeration equipment and the need to improve operating systems.

My May 2 column talked about interest among manufacturers and regulators in introducing more HC refrigerants to the HVACR sector, and I wondered how accepting contractors would be in using such refrigerants. I did receive an e-mail shortly after the column appeared from a contractor in Texas who offered some thoughts.

A lot of talk these days about natural refrigerants focuses on CO2, propane, isobutene, and the like. Stateside, they may be new kids on the block in terms of HVACR applications. But one natural refrigerant that has been around seemingly forever is ammonia. So it - like those “newcomers” - is drawing a lot of attention.

If there is to be a next generation of refrigerants in stationary equipment beyond hydrofluorocarbons (HFCs), it appears they will be hydrofluoroolefins (HFOs). And if that transition is to take place in the United States, it could be because of regulations or better energy efficiencies - or both.

Ammonia in compact systems using micro-channel technology. Building warehouses as high-rises as a way to save energy and reduce ammonia refrigerant charges. Ammonia in integrated heating and cooling systems. These were just some of the directions technical papers took at the recent International Institute of Ammonia Refrigeration Industrial Conference.

A company from Vermont called Freeaire Refrigeration has come up with a technology, according to the company, designed to reduce electrical consumption “by eliminating unnecessary operation of every part of a system” and, for colder climates, adding an element that allows the use of cold outside air.

At the AHR Expo, a large number of the attendees were contractors - and, a lot of them were looking for chillers. McQuay was among those exhibitors with new products. The NEWS worked with McQuay to draw a select group of contractors into the booth to perform a product tour and review, and videotape the proceedings.

Consider the chiller. One of the most basic definitions is “a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required.” But these days a lot more terminology is attached to the equipment.

Every once in a while, a brief quote within all the presentations and comments at a conference will catch my attention as having potentially significant impact. Such was the case at the most recent annual conference of the International Institute of Ammonia Refrigeration.

While CO2 is being successfully used in subcritical applications in the United States, it is more of a challenge in transcritical situations because of demanding compressor technology and high pressures. The UK office of Sanyo Air Conditioners recently issued two case histories showing the refrigerant being used for heat pumps in commercial applications.