MagiCool Technology

Introduction

The concept of evaporative cooling is known for centuries and is quite popular in dry hot climates. It provides for a very effective cooling at a very low energy cost and minimum capital expenses.In selecting an evaporative cooler, the following characteristics need to be considered:

1. Cooling Efficiency, i.e. the absolute physical limit of the lowest temperature achieved by the cooler under the most extreme conditions.
2. Equipment Cost Efficiency, i.e. the cost of the equipment required to cool a defined space.
3. Operating Cost Efficiency, i.e. the cost of energy, water supply, consumable materials, preventive maintenance etc., required to operate a given cooler.
4. Quality & Safety, which have extra importance in coolers due the inherent combination of water  and electricity handling in a consumer environment.

The MAGICOOL represents a major breakthrough in evaporative cooling technology and is superior to conventional coolers in all the above categories.

MAGICOOL Evaporative Coolers

Principles of operation

The MAGICOOL combines a special type of absorbing material with a unique geometry of the "wet region" to generate an extremely efficient cooling system. The moisturizing module consists of parallel porous plates with extremely high capillary effect, which causes the homogeneous distribution of water over the plates surface, while water is supplied at the edges of the plates. The proper choice of material ("media") provides water rise in the plates even against the force of gravity.

The spaces between the plates form rectangular channels for air flowing through them. In contrast to conventional coolers, air in the MAGICOOL technology is flowing in parallel to the plates rather than perpendicular to them. This geometry allows reducing the air pressure drop even for plates spaced about 2 mm apart. A blower (fan) forces relatively dry air through these channels causing the water contained in the plates to evaporate adiabatically, producing a very humid air flow (up to 92% R.H.) and consequently a much reduced temperature. The capillary effect of the porous plates eliminates the need for an additional water pump and re-circulating mechanism. The large contact area between the air flow and the wet surface serves to achieve almost ideal conversion efficiency without increasing the air flow resistance. As a result MAGICOOL technology provides for the design of an extremely wide range of coolers, from units of few thousand CFM to systems of tens of thousands CFM.

Due to the above described constructions and the fact that capillary effect is used to distribute the water over the plates, the cooler has an inherent self adaptation effect, i.e. the water supply adjusts itself to the water evaporation rate, a wide range of inlet, air temperature and humidity.

One of the typical problems of conventional coolers is the effect of salts build-up on the evaporation surfaces, reducing cooler's performance. This effect is an intrinsic feature of commonly used technology, in which there is a continuous supply of water (with dissolved salts in it) to the evaporation surface, where water evaporates, leaving the salts on the surface. MAGICOOL technology allows for a drastic reduction of this effect. The physics of MAGICOOL action maintains a continuous water film connecting the porous evaporation surface with the water reservoir, so that salts ions can move due to diffusion from sites with high ion concentration (evaporation zone) to the those with lower ion content (water reservoir), providing an efficient way of salts ions removal. This MAGICOOL approach bestows an additional major advantage over standard technologies.

Another health related advantage of MAGICOOL is avoidance of bacterial contamination. Because of continuous flow of water (about 3-5 l/h), even the unit is not operating, there is no situation of stagnant or still water. Thus MAGICOOL meets the requirements of Ministries of Health, avoiding the risk of Legionnaire's disease and similar hazards.

The MAGICOOL technology allows approaching to the physical limit of the air temperature drop for any cooling technology based on water evaporation. The next graph presents the maximal possible air temperature reduction by evaporation as a function of the inlet air characteristics. MAGICOOL reduces the air temperature more then 90% of the values on the graph for the same conditions. Temperature values presented on the graph are in the centigrade degrees.

It is easy to see that temperature drop grows for hotter and dryer inlet air, so that MAGICOOL can reduce the temperature by up to 15 – 20°C for desert climate.

The cooler is very easy to maintain as there is only one mechanical moving component – the blower, which is very reliable and has a long life span.

The frequency of required change of the evaporative modules (the "media") is dependent upon the water chemistry.Usually, evaporative modules need to be replaced once in 3 to 5 years.

 

2. The MAGICOOL advantages

The MAGICOOL evaporation efficiency as tested by major independent laboratories is 90% or better. Conventional technologies are at the 60% range.

Energy saving is significant due to the reduced pressure and the elimination of water pumps (resistance evaporative modules Magicool is about 2,2 mm H2O).

Water supply is limited to the exact need due to the self adjusting characteristic of MAGICOOL.

Maintenance costs are kept to a minimum due to the inherent reliability.

MAGICOOL technology results in higher quality as well as safer units. In conventional coolers, extensive corrosion rate is common due to the water coolers and safety is always of great concern due to possible water leaks into electric motors.

Short start-up time to the full performance - the air reaches the lower temperature in about 1 min.

No dragging out of water droplets by the flow, typical to conventional technology.

Avoiding the risk of Legionnaire's disease.

Less salt on evaporation surfaces

 

3. Engineering considerations

The engineering design for the new coolers models was based on the following guidelines:

• Modular and simple internal structure, providing high level of coolers manufacturability

• Minimal manufacturing cost

• Maximal conversion efficiency

• Optimal water and power consumption

• High reliability and maintainability

• Simple installation

• High cost efficiency

• Fulfilment of all demands of national standards regarding coolers design and performance

While most of these guidelines are of general objectives for any engineering design, it is important to point out that the developed models of cooler stand up well to the all above requirements.
The internal structure of the system comprises of the blower, porous plates, water reservoirs and water supply and distribution system. The electrical and mechanical metal components are situated in a way of minimal exposure to the wet airflow and well distanced from the moist zones.  Therefore, possible corrosion and electrical problems are reduced to the minimum resulting in enhanced endurance, reliability and safety of the design. The air entering the blower passes through the filter to remove dust and other particles, which would accumulate on the porous plates and therefore reduce their efficiency. The air flow filtration helps to reduce the noise level as well.      

The process of heat and mass transfer inside the porous plates and out into the air flow in the channel between the plates is very complicated and we will not enter the detailed physical description in this document. In essence there is a coexistence of liquid and vaporized water in the plates, which can be drawn out into the channel by means of pressure gradient which affects the evaporation rate of the water (this effect will be noticeable only for flow velocities of more than 10m/sec).

The porous plates, water baths and upper water distributors are mechanically joined into the module (Evaporative Module) to provide maximal flexibility in design. The designer chooses the blower and calculates the inlet area on the base of predetermined capacity of the cooler and inlet flow velocity. The net cross section area is the ratio of capacity and flow velocity. These parameters establish the necessary number of the wetting modules, water reservoirs and water distribution system characteristics.

The cooler assembly is based on a strong rigid frame, which serves as a skeleton of the device to carry the cooler’s subsystems. The Specifications page demonstrates this concept and show the main measures of the cooler design. The Table cites the range of the developed coolers models and their basic characteristics and the photographs on this page show the main internal structure of the cooler, as well as the unique chilled air distribution sleeve.
The latest models are able to blow the cooled air to the distance up to 25 meters (82 ft).

MAGICOOL units perform successfully in a variety of applications proving the superiority of this innovative technology. Many satisfied customers can testify for the reliability, maintainability and cost efficiency of the cooling solutions provided through the implementation of MAGICOOL technology.

4. Design considerations and parameters.

Range of MAGICOOL Coolers Performance - 3,600 – 35,000 CFM