The efficiency of the refrigeration systems will depend on a correct selection between the condenser cooling technologies, both in terms of energy and ecology. It is essential that all the heat extracted from the food refrigeration chambers, offices, rooms, lounges, warehouses, etc., can be dissipated to the outside environment; as well as the heat of the compression work of the refrigerant in the system.
The implementation of any of the condenser cooling technologies will depend on a climatological study of the region where the refrigeration equipment will be located and on the technical and economic feasibility of the installations.
Cooling technologies and climatological variables of each region
The efficiency of refrigeration systems depends a lot on the geographical location and the climatic conditions of the region. Basically, climates are classified as very cold, cold, temperate, hot, and very hot. Refrigeration equipment will be more demanding in hot and very hot climates.
The temperate climates oscillate between 10 and 20 degrees centigrade; hot climates vary between 20 and 28 degrees Celsius; finally, the very hot ones are between 28 and 38 degrees centigrade.
When talking about ambient temperature, we must distinguish between the dry-bulb temperature (DBT) and the wet-bulb temperature (WBT). Both concepts are closely linked to the relative humidity of the air. Very dry air can have a difference between TBS and TBH of up to 10 degrees Celsius (TBH is always less than TBS). These factors are very important and there should always be a study of the relative humidity of the region, in a period of one year.
Forced Air Condenser Cooling Technologies
These condenser cooling technologies use only air to reject heat, allowing adequate subcritical condensation of the refrigerant. Forced air cooling systems consist of one or more electric draft fans, which bring a flow of fresh air to the condenser coils. To save electrical energy, these electric fans can be controlled with electronic speed variations. In this way, only the airflow that is necessary will be used. This is very important because if the air temperature is 10 degrees Celsius, less flow will be needed than when it is 20 degrees Celsius, for example.
In temperate climates, this type of technology is the most convenient, due to its effectiveness, simplicity, and low cost. These cooling systems work with the dry bulb temperature (TBS).
Evaporative type cooling technologies
Among water-based cooling technologies, evaporative-type cooling technologies are among the most efficient at rejecting heat from condensers. They are the most reliable in hot and very hot climates, in industrial refrigeration with medium and high cooling capacity.
Similar in structure to a cooling tower, these types of condensers have one or more top-mounted draft fans. The forced airflow enters through the bottom of the structure.
The finned condenser coil goes on top, but below the draft fans. A pipe close to the coil sprays a controlled amount of water on it, causing an efficient cooling of the coil, due to rapid evaporation of the water. Finally, the forced airflow from the fan also cools the condenser and removes the heat contained in the water vapor to the outside.
These types of evaporative condensers require more maintenance and special water treatment. In addition, they need to periodically replace all the water that is lost to the outside due to the effects of evaporation; however, by design they have a drop collector, to recover as much water as possible.
It is very important that the recirculating water of these equipment receives a treatment to reduce salt deposits, which can become embedded in the entire structure, reducing its efficiency. Chemicals must also be added to control the growth of algae and Legionella Pneumophila.
Hybrid type cooling systems
In industrial refrigeration, when the climatology of the region allows it, hybrid cooling technologies are used. These can work as forced air only equipment or also as evaporative equipment. Hybrid equipment is designed to work efficiently in both ways, thanks to automatic switching control. The automatic control of the hybrid condenser cooling systems has electronic temperature sensors of dry and wet type to activate the operation of one or the other, at the most convenient moment. Ideally, the evaporative mode should work for the shortest possible time, and thus reduce maintenance costs.
Refrigeration systems with adiabatic cooling of the condenser
Due to the scarcity of water in various parts of the world, adiabatic cooling systems are an alternative to consider in industrial refrigeration, in regions with temperate, hot, and very hot climates.
These units have one or more forced draft fans at the top. They work in a similar way to air-only systems; however, the air, before going to cool the condenser, receives a humidification treatment. Humidification is carried out in hydrophilic panels, which are previously sprayed with water sprinklers. This equipment uses less water than evaporative systems.
These types of adiabatic cooled condensers operate at the wet-bulb temperature. Therefore, when the ambient air is drier, more moisture can be absorbed. Humidification of dry air can lower its temperature by 8 degrees Celsius. Conversely, if the ambient air is very humid, the difference between TBS and TBH is minimal, and adiabatic cooling is no longer practical.
These units have an automatic ‘switching’ control to switch to the adiabatic mode or to air only, thanks to electronic temperature sensors TBS and TBH.
What company can advise me on the maintenance, selection or installation of industrial refrigeration equipment?
Only companies with extensive experience in the design, installation, and maintenance of condenser cooling technologies can assure you of truly reliable service. At Intersam we have specialized engineers and technicians, as well as high-tech equipment to offer an excellent service. We also cover and comply with the strictest environmental protection regulations. And, in addition, we offer cost-effective and durable solutions.