The ammonia condenser is the part of an industrial refrigeration system, based on ammonia, responsible for dissipating all the heat that is being extracted from a refrigerated space to the outside. This dissipation to the outside is carried out by means of forced cooling with ambient air or with water, mainly.
Why is ammonia important as a refrigerant in refrigeration systems?
The European Union, as of 2014, through Law 517, ordered that fluorinated refrigerant gases be gradually replaced in refrigeration systems. The reason for all this is that industrial residues of such gases rise into the atmosphere and destroy the ozone layer. For this reason, both ammonia and CO2 have regained greater importance, to replace fluorinated gases.
Large-scale industrial refrigeration, since 1876, has been dominated by ammonia. This is because ammonia is a much cheaper gas and has better thermodynamic properties compared to F-gases. However, installations are more expensive, require safety devices, and are only profitable in high-demand refrigeration applications.
Fluorinated refrigerant gases are used in all industrial, commercial and residential refrigeration systems, from medium to low power. The definitive substitution of fluorinated gases, by ammonia, will depend on the technological development that allows: for lowering the costs of the installations, improving safety, and reducing the size of the installations.
Types of ammonia condenser
The types of ammonia condensers depend on the method and the physical medium they use to dissipate heat to the outside. In this sense, you can get the condenser with a water heat exchanger, the air-cooled condenser, and the evaporative or ammonia evaporation condenser. Next, we explain the constitution and operation of each one:
Ammonia condenser with water heat exchanger
This ammonia condenser is made up of a coil of stainless steel tubes, through which ammonia circulates at high temperatures. The coil goes inside a cylindrical steel structure, through which freshwater circulates at room temperature. Inside the cylinder, the freshwater absorbs the heat from the ammonia and draws it out of the cylinder.
This system is effective when there is a nearby and abundant natural water source. If you don’t have that source, you will need a pool and a cooling tower to refresh the water that will be constantly recirculating through the heat exchanger.
In industrial refrigeration, it is very common to find this type of refrigeration equipment with condensers cooled by water, through heat exchangers.
Air Cooled Ammonia Condenser
On occasions when the annual average air temperature is cool (eg 25°C), ammonia can be cooled by air alone. In this type of refrigeration equipment, the ammonia is circulated through a coil of stainless steel tubes, which goes inside a metal structure. A group of high-flow fans circulate outside air inside it and cool the ammonia.
Ammonia evaporation condenser
Also called an evaporative condenser, this cooling system is widely used when there is no abundant water source and when the ambient air is hotter (greater than 30° C).
This ammonia condenser is a cooling tower with large fans, which go on top. The stainless steel coils that carry the ammonia are placed inside. On the other hand, in the lower part, there is a cooling water tank, which is driven by a pump to the upper part. The pumped water is sprayed on the coils and falls by gravity back to the tank.
The water sprayed on the surface of the coils evaporates very easily, extracting heat with maximum efficiency. Finally, the flow of ambient air driven by the fans absorbs the water vapor and removes the heat to the outside.
The efficiency of the ammonia evaporation condenser or evaporative condenser depends on the temperature and relative humidity of the air. When the relative humidity of the air is more than 60%, the efficiency of this refrigeration equipment is almost equal to that of the air-cooled condenser. For this reason, the study of the relative humidity of the air in the place is decisive to install this type of condenser.
Safety measures of all ammonia refrigeration equipment
Ammonia is a toxic and potentially explosive gas. For this reason, the complete refrigeration system, as well as the ammonia condenser, must-have electronic devices to detect ammonia leaks, which allow preventive safety control action to be taken.
On the other hand, electrical installations such as motor connection boxes, lamps, switches, pipes, etc., must have explosion protection. This protection is essential to prevent the propagation of electrical sparks that can cause a fire or explosion, due to the reaction with the ammonia accumulated in accidental leaks.
An ammonia refrigeration system must have safety valves, to relieve occasional overpressures, in any part of it. These safety valves will conduct the overpressure to the external environment, avoiding any accumulation of ammonia in closed spaces. In addition, the installation spaces must have exhaust fans.
Who can I get advice on regarding an ammonia refrigeration system?
INTERSAM S.L. is a company from Madrid with almost three decades dedicated to industrial refrigeration, from the design stage to installation and commissioning. We guarantee a refrigeration equipment that really meets your needs and meets the highest standards of safety and energy efficiency.
Among other things, at Intersam we are specialists in the design and manufacture of heat exchangers. If you need an ammonia condenser for your company, we can advise you and manufacture just the one you need. In this sense, we offer you an ammonia evaporation condenser or evaporative condenser according to your particular industrial process.