It will become increasingly common to find an NH3 capacitor where there used to be another capacitor designed for synthetic refrigerants. Ammonia (NH3) is a natural refrigerant that has regained significant global relevance due to the severe restrictions placed on synthetic fluorinated refrigerants.
Although fluorinated refrigerants displaced ammonia, this natural refrigerant maintained a presence in large industrial refrigeration systems worldwide. However, its usage is now expanding to gradually replace fluorinated refrigerants in industrial and commercial systems.
What is an NH3 capacitor?
An NH3 capacitor is a device designed and manufactured to work with ammonia. It is responsible for transferring all the heat from gaseous ammonia to the external environment, allowing the gas to condense (liquefy). The ammonia entering the capacitor comes from the compressor of refrigeration systems at high temperature and pressure.
Types of NH3 capacitors
There can be various types of NH3 capacitors, depending on the technical aspects taken into account. In this post, we will discuss those that differ in how they dissipate heat into the environment.
Chiller-type NH3 condenser
This type of condenser cools and condenses ammonia vapor using fresh water within a shell-and-tube heat exchanger. In these systems, gaseous ammonia flows through the inner tubes, and water passes through the shell. This way, the water effectively cools the gaseous ammonia.
Forced-air ammonia condensers
Forced-air condensers use air exclusively for cooling ammonia. These systems are suitable when the air temperature is below 25°C. They don’t require water like chillers do, but they use large heat exchange coils. In these condensers, forced air from one or multiple fans passes through the coils, cooling the ammonia circulating inside.
Evaporative ammonia condensers
When forced-air condensers have a system of nozzles to atomize pressurized water, they become evaporative units. In these systems, atomized water wets the ammonia coils, increasing heat transfer to the environment through water evaporation. Therefore, these units cool ammonia with the fans’ air and water evaporation, enhancing cooling capacity.
Evaporative condensers are highly useful in summer or tropical areas with temperatures exceeding 30°C. They are usually designed to work only with fans when the ambient temperature drops below 28°C.
Adiabatic cooling condensers
These are also forced-air condensers but incorporate adiabatic cooling of forced air. Adiabatic cooling involves increasing the air’s relative humidity by passing it through hydrophilic panels. Consequently, the air reaching the coils has a lower sensible wet-bulb temperature. As a result, the coils cool more efficiently.
Adiabatic condensers consume less water than evaporative condensers or chillers. They’re ideal for working in ambient temperatures above 30°C. Moreover, they can operate only with fans when the air temperature has dropped below 30°C.
Importance of ammonia refrigeration systems
European regulation 517/2014 will prohibit the marketing of any type of fluorinated refrigerant gas by 2030. This law will also prohibit the marketing of equipment that uses such gases. This affects industrial refrigeration, which consumes large amounts of fluorinated gases.
This regulation has increased interest in installing new ammonia refrigeration plants. In this regard, many refrigeration equipment manufacturers have begun to develop improvements in NH3 condensers, NH3 valves, NH3 compressors, etc. However, replacing fluorinated gases with ammonia is not an easy task, as the two refrigerants are quite different.
Technical challenges of ammonia implementation
Fluorinated gases (HFC and CFC) have a lubricating effect that reduces wear on compressors. However, ammonia accelerates friction and wear. For instance, mineral lubricants mix perfectly with fluorinated gases but not with ammonia. Consequently, ammonia and oil form a foamy mixture with low lubricating power.
Additionally, the compression temperature of ammonia is higher than that of fluorinated refrigerants. Moreover, the issue of ammonia’s toxicity increases safety system costs.
Intersam: Experienced manufacturer of NH3 condensers
The NH3 condenser is a crucial part of any ammonia refrigeration system. At Intersam, we guarantee an ammonia condenser made with high-quality AISI 304L stainless steel tubes, 0.8mm thick. The tubes are joined with inert gas TIG welding. Moreover, the stainless steel tubes have aluminum fins spaced 2mm apart. The entire structure is made of galvanized sheet metal to better withstand outdoor environmental conditions.
Furthermore, at Intersam, we manufacture the NH3 condenser with the iDrop adiabatic cooling system. The iDrop system can increase the air cooling humidity to up to 90%, with minimal water consumption. This system has precise water dosing control. Additionally, the hydrophilic panels of the iDrop system surpass any other panel on the market due to their unique design and material.