All about the natural refrigerant ammonia (NH3) in cooling & refrigeration: News, Products, Jobs, Events, Knowledge, Forum, B2B Networking.

Sobey’s refrigerated warehouse in eastern Canada has been honoured with the ASHRAE 2010 Technology Award for its innovative building design, including the use of an ammonia central chiller and heat recovery on the condenser side of the chiller for space heating.

The ammonia central chiller and glycol secondary distribution fluid system keep the 120,000ft² (11,148m²) of refrigerated warehouse section at 4°C (39°F). A free cooling refrigeration system has been designed to make use of exterior temperatures lower than the desired temperature in the refrigerated warehouse that often occur at Trois-Rivières, where the warehouse is located. This allows the chiller to operate in free cooling mode by using the thermosiphon principle, with the compressors stopping when the outdoor temperatures are below 10°F (-12°C).

Heating and cooling of offices and common spaces

Heat recovery from the chiller condensers caters for most of the heating needs for the offices and common spaces totaling 26,000ft² (2,415m²). When the chiller operates in free cooling mode, heating is provided by backup gas boilers.

The ammonia chiller also caters for the cooling needs of the office areas. To maximise energy efficiency for this application, the chiller has two different pressure inputs to produce two different temperatures - one for the office area and one for the warehouse.

Operation and Maintenance

Maintenance is simplified with all refrigeration and heating systems being centralised in a mechanical room and the water and glycol loops being equipped with balancing valves.

Energy savings

Having one central ammonia chiller instead of several direct expansion evaporators allows for higher efficiency. This combined with other sustainability features of the warehouse have resulted in energy savings to amount to $144,896 and the simple payback period to less than seven years based on DOE-2 energy simulation.