Combined Flow Configuration
BAC manufactures two types of evaporative condensers: combined flow and counterflow. Combined flow is the use of both a condensing coil and fill surface for heat transfer in an evaporative condenser. The addition of fill surface to the traditional evaporative condenser design reduces evaporation in the coil section, reducing the potential for scaling and fouling. BAC’s combined flow evaporative condensers utilize parallel flow of air and spray water over the coil, and crossflow air/water flow through the fill surface. In parallel flow, air and water flow over the coil in the same direction. In the fill section of BAC’s combined flow evaporative condensers, air and water interact in a crossflow configuration: water flows vertically down the fill as air flows horizontally across it.
ImageCounterflow Configuration
In a counterflow evaporative condenser design, the flow of the air is in the opposite direction of the spray water. In BAC’s counterflow evaporative condensers, air travels vertically up through the unit while the spray water travels vertically down over the coil. The flow of air through most factory assembled evaporative condensers is provided by one or more mechanically driven fans.
ImageInduced Draft
The rotating air handling components of induced draft equipment are mounted in the top deck of the unit, minimizing the impact of fan noise on near-by neighbors and providing maximum protection from fan icing with units operating in sub-freezing conditions. The use of corrosion resistant materials ensures long life and minimizes maintenance requirements for the air handling components.
Forced Draft
Rotating air handling components are located on the air inlet face at the base of forced draft units, facilitating easy access for routine maintenance and service. Additionally, location of these components in the dry entering air stream extends component life by isolating them from the corrosive saturated discharge air.
Reduces Fouling Tendency
Advanced coil technology, applied on CXV Evaporative Condensers, is used to reduce the tendency to accumulate fouling and scale on the coil’s exterior surface. Four facets of the unique product design contribute to the reduced tendency for fouling:
The Air and Water Flow in a Parallel Path
Better water coverage over the coil is maintained because the air and spray water flow in a smooth, parallel, downward path over the coil. With this parallel flow, the spray water is not stripped from the underside of the tubes by the upward air flow, as on other, conventional designs. This eliminates scale-producing dry spots on the coil.
Increased Water Flow Over the Coil
The spray water flow rate over the coil plan area is more than twice that of conventional units. This heavy coverage provides continuous flooding of the primary heat transfer surface for decreased fouling potential. Improved spray water coverage is provided at no increase in pumping horsepower due to the unique heat transfer system of the design.
Evaporative Cooling Occurs Primarily in the Fill
CXV models incorporate combined flow technology, using both primary and secondary heat transfer surfaces. The primary heat transfer surface is the serpentine coil, which is the most important and expensive component in the unit. In BAC’s combined flow design, more than 80% of the latent heat transfer occurs in the secondary surface, PVC cooling tower fill , effectively moving the evaporation process away from coil. The coil is protected from detrimental fouling and scale since it relies primarily on sensible conduction/convection heat transfer and, therefore, is less susceptible to scale formation than are other designs that rely primarily on latent (evaporative) heat transfer.
Colder Spray Water
Spray water at a colder temperature has a lower propensity to form scale because scale-forming compounds remain in solution, rather than deposit as solids on the coil exterior surface. Spray water flowing over the coil is commonly 6°F to 8°F colder than on other designs due to the addition of the secondary heat transfer surface. Colder spray water alone typically reduces the scaling potential* by 25% compared to other designs. This is over and above the fouling reductions achieved by the first three factors described above.
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*Using Langelier Index
The maintenance of stable process temperatures is critical to the success of many industrial and manufacturing processes. Industrial-scale temperature regulation cannot be achieved using conventional, portable cooling systems. In these instances where larger-scale cooling is desired, industrial capacity cooling systems are the most efficient way to maintain process temperatures at optimal ranges.
Depending on the manufacturer, cooling systems come installed with various condenser types including evaporative systems. This article will compare the various cooling towers and evaporative condensers available for industrial use and highlight the differences between both cooling systems.
An evaporative condenser is a device that converts refrigerant contained within a closed circuit from a heated vapor to a cooled liquid form by the evaporation of water sprayed on the exterior surface of the refrigerant tubing. It is essentially a hybrid between an air-cooled condenser and a water-cooled condenser which uses the principles of heat rejection to follow an evaporative process.
The condenser component of an industrial chiller system functions as a heat transfer device between a process and its external environment.
Condensers can either be air-cooled, water-cooled or evaporative in design and function. Regardless of type, all condensers have a similar function: to transfer heat away from a refrigerant gas and thereby cool the required process or equipment.
Evaporative condensers are divided into two main types
Forced draft evaporative condensers pull air through the unit at its base, condenses it and releases it in a saturated form through an opening at the top of the cooling unit. This condenser type could either be a centrifugal fan-driven type or an axial type which is the most common set up available. The choice of forced draft condenser type depends on careful consideration of the features of each type and their efficiency in achieving cooling.
This is the most common evaporative condenser in use industrially. It is mostly utilized in large scale industrial applications for rapid cooling. This forced draft condenser type has some advantages which include:
Centrifugal fan models are utilized in cooling applications where sound may constitute a problem. These devices are generally quieter than their axial fan counterparts and as a result, centrifugal fan-type condensers can be installed in indoor locations. These evaporative condenser variants can be employed in halocarbon air-conditioning units and work quite efficiently.
Induced draft evaporative condensers work by pulling air in the chiller environment through a condenser mounted at its base. The collected air is condensed and circulated to cool the associated process. Benefits of this condenser type include:
The advantages of opting for evaporative condensers are linked to process cost-savings. The main points are highlighted below:
The major difference between a cooling tower and an evaporative condenser chiller setup lies in the number of stages required to achieve their cooling effects.
For chiller systems that utilize a cooling tower, heat transfer from the cooling process involves two stages. The heat generated by an industrial or commercial process is first transferred to the circulating chiller fluid by the condenser unit before atmospheric heat rejection at the cooling tower. Thus, using chillers and cooling towers together require two levels of heat exchange.
On the other hand, chillers with evaporative condensers achieve similar results by a single heat rejection process which involves the evaporation of heated water from the external surface of the coolant tubing.
For over three decades, Cold Shot Chillers has offered top-quality industrial chillers. Our priority remains the delivery of satisfactory customer experience to all clients through the provision of reliable process cooling solutions.
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