The following is a case study of a CO2 refrigeration project carried out at a renowned supermarket in Panama City.
by Duvan Agudelo Chaverra
The refrigeration systems and their facilities are presenting new technology alternatives that aim to improve the operation of the spaces and therefore the efficiency of the system so that the results are much more satisfactory for the client.
This time we will present a case of success on the provision and installation of a commercial refrigeration system made in Panama, more precisely in the new supermarket Riba Smith in Costa Verde located within the market plaza Market Plaza. As a new store, the whole project was done from scratch.
The project consisted of the installation of the display refrigerators in the different models required, the cold rooms with their doors and the refrigeration unit in CO2 suscrítico, which works in CO2 suscrítico in direct expansion (DX) for the low temperature and in CO2 liquid pumped for medium temperature. All these equipments were manufactured by Arneg Group in its factory located in Italy.
It should be noted that the installation was in charge of the company Crio who already have four refrigeration systems installations CO2 in Panama for this same customer (Riba Smith).
It is understood that the subcritical CO2 system is ideal for large capacity installations in hot climates, offering substantial savings in energy consumption and providing a large volumetric cooling capacity with reduced refrigerant loads.
The system installed in the Riba Smith supermarket is cascade type. In this regard, Pablo Buchko, Central Director for America & Caribbean of Arneg Central America commented: "The primary system consists of two racks of R134a that are only used to cool the CO2 of the system to make it liquid. Then the media system uses a liquid CO2 pumping station (34barg / 34barg) much like a glycol pumping system, but with the advantage that due to CO2's volumetric cooling capacity the pipe diameters, the dimensions of the pumps and the evaporators are considerably smaller. The low temperature system utilizes a CO2 direct expansion rack (10barg succ./28barg cond.) Which also takes advantage of CO2's larger volumetric cooling capacity and uses smaller components than a system with common refrigerants (R404a / R507) ".
"It is important to note that although the dimensions of the system components (pipes, valves, compressors, pumps, evaporators) are reduced, the pressures of the system are considerably higher than those of a conventional refrigeration system. Therefore, operating pressures and temperatures during the design stage must be taken into account in order to select components that can withstand the high pressures of CO2.
Meanwhile, in order to avoid difficulties during the execution of a project such as these, Paul emphasizes the importance of selecting the right components to make the system work.
"As in any engineering project you must choose the appropriate components to ensure the operation and longevity of the system to be installed. This is of paramount importance in a refrigeration system with CO2. All components of the system must be made to withstand the low temperatures and high pressures to which the CO2 circulates in the system. In addition, relief valves must be installed in travel and safety valves to relieve CO2 pressure that expands in the event of loss of electrical power and the operating window of the backup cooling system.
The installation of refrigeration systems with CO2 has been presenting more and more projects due to the different benefits in operation, efficiency and because it is environmentally friendly due to the non-impact of the ozone layer. These and other reasons led Arneg and the company Crio to select this system for the supermarket.
"CO2 is a common, abundant and low-cost gas. The CO2 having a minimal impact on the greenhouse effect is used as a reference with a GWP value equal to 1. In addition, it has no impact on the ozone layer (ODP = 1). These characteristics classify CO2 as a natural refrigerant and make it a very attractive alternative with the new refrigerant restrictions that have been imposed worldwide for the care of the environment. By combining these CO2 features as a state-of-the-art refrigerant developed by Arneg Group we can provide considerable savings to our customers in the operation of the system as we have smaller components working at their optimum efficiency points, "commented the central director of the manufacturing company.
Being this the fourth store of Riba Smith in which the refrigeration system with CO2 is installed shows that the project is being well received by the customer, as Pablo Buchko says in his closing remarks: "Our customer is satisfied with the system, so this is the fourth store in which we install this technology. The customer is seeing a great energy saving and the use of CO2 as a refrigerant positions them ahead of the market in terms of natural refrigerants and their adherence to the new world regulations.
Signature installer: CHILD
Manufacturers involved: Arneg Central America
Company or place covered with the installation: Riba Smith Market Plaza