> Fog Theory > Advantages over Pad Cooling (greenhouse & poultry environments)
The theoretical potential for evaporative cooling is essentially the same for both cooling pads and MicroMist fog systems. Properly designed, both can reduce temperature to within 4°F (2°C) of wet bulb temperature. The primary difference between the two technologies is that cooling pad systems utilize manufactured cellulose media to suspend moisture in an air stream, while the MicroMist System atomizes water to a fine spray, suspending it in the air for evaporation.
Below is a summary of the significant differences between these cooling technologies.
MMS: Can be successfully retrofitted to virtually any structure, with any ventilation conditions - mechanical or natural, tunnel- or cross-ventilated.
Pads: Require specific ventilation characteristics for maximized cooling. Typically pad cooling is only recommended for mechanically ventilated structures.
MMS: Automatic temperature control facilitates rapid response time, as atomized water enters the air stream and evaporates almost immediately. This creates the ability to maintain tight temperature ranges (as little as 2°F / 1°C, depending on air flow conditions).
Pads: Although automatic temperature control is available, cooling response is slower, as the pads gradually become completely wet at startup, and are slow to fully dry out at shutdown.
MMS: Temperature gradients are neutralized by the total-coverage designs of the MicroMist System. Vertical and horizontal fluctuation in temperature is typically limited to 2°F (1°C) at most.
Pads: Significant temperature differentials are virtually unavoidable. As air is treated generally only at one end of a given structure, temperatures often vary both vertically and horizontally throughout.
MMS: Atomized water is suspended in the air stream until it evaporates, allowing for mechanical ventilation rates to be independantly maximized for optimal air circulation and uniformity of conditions.
Pads: Slow air flow velocities are typically required in order to produce the optimal evaporative cooling conditions. This reduces the total capacity for adequate air circulation and uniformity of conditions.
MMS: The closed water system, with properly specified filtration and water treatment, prevents external contaminants from degrading cooling capacity. Air flow volume and velocity are never significantly affected by the fog system.
Pads: The open water system, coupled with the necessary negative air pressure ventilation design, causes the pad cooling media to attract external debris, algae, and bacteria. This unwanted builup reduces air flow, as well as overall cooling capacity.
MMS: Preventive maintenance recommended to insure consistent performance includes periodic filter and oil changes, as well as occasionally verifying that all nozzles are operational.
Pads: Recommended preventive maintentance can include pressure washing the pad media as often as once a week to remove debris. Pressure washing will not prevent buildup of dissolved solids on the pads, however. This typically cannot be prevented, and will eventually degrade system performance.
MMS: If replacement of individual nozzles ever becomes a necessity, replacing only those which are non-operational will return the system to maximum cooling efficiency.
Pads: It is expected that optimal cooling system performance will require periodic replacement of all pad media at once within the given structure several times throughout the life of the cooling system. This results in significant additional expense for freight and labor charges.
MMS: Nearly 100% of water consumed is used for cooling. Resources are used efficiently and waste water production is minimized.
Pads: Recommended water bleed-off (to reduce buildup of dissolved solids in the recirculation system) is often equivalent to 100% of water usage for cooling. This amounts to grossly inefficient water usage and production of excess waste water.
MMS: Depending on the system design and customer requirements, the same MicroMist System that cools the air can be used successfully to: decrease airborne dust and static electricity levels by humidification, vastly reduce pest populations, disinfect entire areas at once, abate environmental odors, and double as a pressure washer to accomodate special needs.
Pads: In addition to cooling, pad systems can typically only offer marginal environmental humidification effects.
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