In the environments of certain industrial sectors or applications, where air conditioners operate, aggressive and corrosive agents may be present, such as: chloride/sulphur compounds (coastal areas), sulphur oxides/nitrogen oxides (polluted industrial areas), airborne particles/cutting oils/solvents in factories, presence of iron dust, ammonia, sulphur oxide in the air. These substances lead to various corrosion or oxidation phenomena.

The main components subject to deterioration include the external housing, electrical components and the cooling circuit on the condensing/external side of the unit

Corrosion is the deterioration of a material due to certain chemical reactions triggered by substances in the environment that change the state of the material.

In galvanic corrosion, deterioration occurs when two different metals come into contact with each other in the presence of an electrolyte, which may be moisture. Between the two metals there is a migration of ions and therefore an electric current, which causes corrosion in the metal with lower electronegativity, called the anode.

Another type of corrosion is oxidation, or rather called oxidation-reduction: electrons are reduced in a substance, which thus has an increase in its oxidation number; an example of which could be iron, where rust is formed due to prolonged exposure to air and moisture.

Furthermore, there is corrosion due to the attack of specific acidic substances in the environment, such as hydrochloric or hydrogen sulphide.

The city’s wastewater treatment service enables the conversion of residual sludge into biogas for the production of electricity. The centrifugal extractors or pumping systems are located on this site and are supported and controlled by an electrical control panel, which is designed to control and distribute power and manage the process parameters. The equipment inside the panels develops a considerable thermal load, which must be disposed of and therefore conditioned. In this kind of environment are present some substances, such as ammonia, sulphur oxides, hydrogen sulphide, which make the atmosphere very corrosive and create problems of deterioration of pipes and electrical components, significantly affecting the parts with copper or electrical contacts.

With two special Protherm products CVE0800220Z003 and CVE2000261Z000, Cosmotec offers an air conditioning solution with increased corrosion resistance. The two air conditioning units are therefore suitable for operation in very critical working conditions and have a longer average life than standard air conditioning units. This is possible thanks to dedicated solutions to protect elements of the carpentry, the cooling circuit and the electronic control, components that are more subject to possible corrosive attack in certain environments with chemically aggressive substances.

The printed circuit of the electronic board, however, located on the evaporator/cabinet side, and the display, installed on the panel, are covered with a protective resin layer that prevents substances or moisture from depositing on the conductive copper tracks.

The panel, part of the housing, which is mainly exposed to the external environment, is made of stainless steel, which has resistance properties against corrosion/oxidation phenomena.

The exchangers (condenser and evaporator), the largest elements of the refrigeration circuit, are protected by a specific treatment depending on the type of component. In addition, the external part of the refrigeration circuit, both pipes and welds, are also coated with a treatment to increase protection against the action of corrosive agents.

The above mentioned air conditioners are also available in a version with a painted sheet metal panel (codes: CVE0800220Z004, CVE2000261Z001) in case only the protection of parts with copper is required.

A viable alternative, if water is available and can be used as the cooling medium, are EXW water/air exchangers, as they have no parts of the unit exposed to the outside environment. The air/water exchangers are optionally available in a version with stainless steel casing.