Evaporative condensers achieve efficient heat exchange through the synergistic interaction of water and air; however, scale buildup on the water side significantly reduces heat transfer efficiency, increases energy consumption, and can even cause equipment corrosion. Optimizing structural design can reduce the scale buildup rate and extend the condenser's lifespan by considering fluid distribution, material selection, surface treatment, flow field optimization, component layout, water quality adaptability, and modular design.
Optimizing the spray system layout is one of the core measures to reduce scale buildup. Traditional designs often result in insufficient water flow in certain areas due to insufficient nozzle spacing or uneven distribution, creating dry spots that allow salt to deposit on the pipe walls. Increasing the nozzle spacing and using a staggered arrangement expands the spray coverage, ensuring a uniform water film covering the coil surface. Simultaneously, a double-layer spray structure is employed: the upper layer forms the initial water film, while the lower layer replenishes the water flow and flushes away existing scale, preventing impurities from remaining on the pipe walls. Furthermore, adding baffles to the spray lines guides the water flow in a spiral pattern, enhancing the flushing force on the coils and reducing scale adhesion. The material and surface treatment of the coil directly affect scaling tendency. Ordinary carbon steel pipes are prone to rust formation due to electrochemical corrosion, becoming the core of scale formation. Hot-dip galvanizing can form a dense zinc layer on the steel pipe surface, isolating water from the substrate, while the sacrificial anode effect of zinc can slow down the corrosion process. Further selection of copper alloy or stainless steel coils, although more expensive, significantly improves surface smoothness and reduces scale adhesion. In terms of surface treatment, mechanical polishing or chemical etching processes can reduce pipe wall roughness, decreasing the scale adhesion area. Some designs also coat the coil surface with a hydrophilic coating to enhance water film stability and inhibit salt crystallization.
Flow field optimization is a key technology for reducing scaling. In traditional evaporative condensers, the counter-current air and water flow easily creates a vortex zone at the bottom of the coil, leading to reduced water flow velocity and impurity deposition. By adopting a co-current flow design, aligning the air and water flow directions, water film fluidity can be enhanced, avoiding local stagnation. Meanwhile, a guide cone is added below the coil to evenly guide airflow into the coil gaps, reducing the impact of airflow on the water film and maintaining its integrity. Furthermore, optimizing the coil arrangement, such as using spiral coils or irregularly shaped tube bundles, breaks the inertia of water flow, enhances turbulence intensity, and makes it difficult for impurities to remain on the tube walls.
The rationality of component layout is crucial for scaling control. In traditional designs, the distance between the air inlet and the coil is too small, easily causing dust in the air to directly adhere to the coil surface. By increasing the vertical distance between the air inlet and the coil and installing multiple layers of filters at the air inlet, most dust particles can be intercepted. Simultaneously, designing the water tank with a sloping bottom structure and adding a drain outlet at the bottom allows for the periodic removal of settled impurities, preventing them from being re-carried into the spray system by the circulating water pump. In addition, a baffle plate is installed above the coil to prevent spray water from splashing onto the evaporative condenser casing, reducing the entry of corrosion products from casing rust into the water system.
Water quality adaptability design can fundamentally reduce the risk of scaling. For areas with high water hardness, an electronic water processor can be added to the circulating water system. This processor uses electromagnetic fields to alter the crystallization morphology of calcium and magnesium ions in the water, causing them to form loose, soft scale rather than dense, hard scale. For water with high bacterial counts, ultraviolet sterilizers or chemical disinfectant dosing devices can inhibit algae and microbial growth, preventing the formation of biological slime. Furthermore, a detachable coil module design facilitates regular chemical cleaning or high-pressure water flushing to thoroughly remove stubborn scale.
Modular and standardized design provides a long-term solution for scale control. By designing coils, spray systems, fans, and other components as independent modules, suitable components can be quickly replaced for different water quality conditions. For example, stainless steel coil modules can be used in highly corrosive areas, while automatic backwashing filter modules can be added in dusty areas. Simultaneously, establishing standardized interfaces and installation specifications ensures compatibility between modules and reduces the difficulty of later maintenance.
