Costa Rica. Coca-Cola Liberia's headquarters, located in the province of Guanacaste, installed a direct expansion and low-load ammonia refrigeration system, a project in which the contractor: Refrigeration and Cold Solutions (RSF) participated.
The project required commissioning the entire refrigeration system of the plant that included air conditioning, cooling of process water and air conditioning of the refrigerated storage chambers and frozen chamber.
"One of the most important conditions was to carry out an energy-efficient and environmentally friendly project, and although the project was originally designed with ammonia, the power required and the volume of refrigerant in the system made the application of this natural refrigerant doubtful," said Eng. Lisandro Salas Mora, General Manager of RSF.
At the refrigeration level, the plant required 750 tons in air conditioning, 150 tons in cold water system for processes and 208 tons in refrigerated and frozen storage systems. Originally the project was designed by other professionals, and the questioning at that time was not exactly the refrigerant but rather that it was oriented towards the volume of ammonia in the system. The original design considered approximately 8 thousand pounds of ammonia.
"We used low-charge refrigerant evaporators, we're talking about 2-pound equipment per team, and we kept the original design of plate exchangers for cooling process water, air conditioning water and propylene glycol, which in one way or another are also low-refrigerant load equipment," said Eng. Salas.
Another goal of the project was to increase the energy efficiency of the system; by raising evaporation temperatures and lowering the installed capacity, it represented an approximate annual saving of US$250,000.
Additionally, the project went from having eight compressors in its original design, to six screw compressors of the same Frick model, which meant safety and an additional benefit from the point of view of maintenance.
"The six screw compressors are identical in terms of power and model. We have three plate exchangers: one for process cooling, one for air conditioning water and another for propylene glycol cooling with which we air condition the refrigerated storage chambers called water house and flammable cool, "said Eng. Lisandro.
An ammonia dehydrator was also installed in the facility, which was incorporated to remove any moisture or water and thus maintain the efficiency of the system.
Similarly, the new automation system allows you to control and monitor the entire cooling system from the engine room. Security and leak detection solutions that comply with IIAR standards were incorporated. In this engine room the entire volume of ammonia is concentrated, around 2,800 pounds, that is, 5,000 pounds less than the original design.
It is important to mention that the new design considered the heat of the oil for the heating of the frozen floor, and taking advantage of that residual energy a radiant floor was built.
The main achievements of this project
- Lowered the installed power of the equipment by approximately 350 KW.
- Increased energy efficiency by 13%.
- Lowered the volume of ammonia by 4,822 pounds.
- Ammonia was maintained as a refrigerant with zero GWP.
- The heat of the compressor oil was used to build a radiant floor.
- Redesigned under The IIAR standards of Inteco Costa Rica.
- The investment was lowered.
