Ozone Generator Cooling
Ozone generators must be cooled. This includes both the power supply unit (PSU) as well as the ozone generator
vessel. The PSU and controls may be cooled by standard Cabinet fans or have air conditioned air forced into the
cabinets.
Small ozone generators may use air cooling for the generating vessel. Larger ozone generators almost always use water
cooling. Air cooling helps reduce the cost of the ozone generator, but also makes production dependent on the ambient
conditions of the ozone generator. In some cases, air cooled ozone generators must be must be operated in air
conditioned rooms. Air cooled systems rarely are used for more than several pounds per day of production.
Water cooling adds capital expense, but improves control over the temperature of the ozone generator. In large systems,
water is the only effective way to move the amount of heat generated. Three types of water cooing systems are used:
once through systems, indirect/once through systems and closed loop systems with chillers. The availability of good
quality water and the temperature of the water are factors in selecting the cooling water source.
The delta T across the ozone generator is usually specified from 5 - 10 degrees F. The flow of cooling water for the
ozone generating vessel can be between 0.6 and 1.2 gpm/kW of applied power. Additional water may be used to cool the
PSU in very large systems. These figures are dependent on the cooling water temperature. Spartan specifies a cooling
water flow of 0.5 gpm with an inlet temperature of 50 degrees F and an outlet temperature of 59 degrees F.
The quality of the cooling water in important to prevent scaling of the heat exchange surfaces and/or corrosion of the
generator. For the most part, ozone generators are made from stainless steel. Elevated chloride levels in the water
above 50 ppm can result in corrosion. As with any heat exchanger, scale can form on the heat exchange surface and
reduce the effectiveness of the generator's cooling. With respect to biological fouling, some of the ozone generated can
be used to maintain micro biological control. Thermal scaling can be prevented with chemical additions.
One through systems can use treated water for cooling. In certain regions of the world, the water can be quite warm.
The higher the temperature of the cooling water, the less efficient the production of ozone. At maximum output an
increase in the inlet temperature of the cooling water from 59 degrees F to 77 degrees F can reduce generator output by
15%. This can be compensated for by using a larger ozone generator than would be needed with lower temperature
cooling water. In some cases, this may be more economical than using a chiller system:
The once through indirect cooling system employs a plate and frame heat exchanger between the ozone generator and
the open loop cooling water source. This protects the ozone generator from water quality issues while maintaining an
economical cooling system.
Ozone generators must be cooled. This includes both the power supply unit (PSU) as well as the ozone generator
vessel. The PSU and controls may be cooled by standard Cabinet fans or have air conditioned air forced into the
cabinets.
Small ozone generators may use air cooling for the generating vessel. Larger ozone generators almost always use water
cooling. Air cooling helps reduce the cost of the ozone generator, but also makes production dependent on the ambient
conditions of the ozone generator. In some cases, air cooled ozone generators must be must be operated in air
conditioned rooms. Air cooled systems rarely are used for more than several pounds per day of production.
Water cooling adds capital expense, but improves control over the temperature of the ozone generator. In large systems,
water is the only effective way to move the amount of heat generated. Three types of water cooing systems are used:
once through systems, indirect/once through systems and closed loop systems with chillers. The availability of good
quality water and the temperature of the water are factors in selecting the cooling water source.
The delta T across the ozone generator is usually specified from 5 - 10 degrees F. The flow of cooling water for the
ozone generating vessel can be between 0.6 and 1.2 gpm/kW of applied power. Additional water may be used to cool the
PSU in very large systems. These figures are dependent on the cooling water temperature. Spartan specifies a cooling
water flow of 0.5 gpm with an inlet temperature of 50 degrees F and an outlet temperature of 59 degrees F.
The quality of the cooling water in important to prevent scaling of the heat exchange surfaces and/or corrosion of the
generator. For the most part, ozone generators are made from stainless steel. Elevated chloride levels in the water
above 50 ppm can result in corrosion. As with any heat exchanger, scale can form on the heat exchange surface and
reduce the effectiveness of the generator's cooling. With respect to biological fouling, some of the ozone generated can
be used to maintain micro biological control. Thermal scaling can be prevented with chemical additions.
One through systems can use treated water for cooling. In certain regions of the world, the water can be quite warm.
The higher the temperature of the cooling water, the less efficient the production of ozone. At maximum output an
increase in the inlet temperature of the cooling water from 59 degrees F to 77 degrees F can reduce generator output by
15%. This can be compensated for by using a larger ozone generator than would be needed with lower temperature
cooling water. In some cases, this may be more economical than using a chiller system:
- A once through system is substantially less expensive than a chilled water system
- A chiller system adds to maintenance costs
- A chiller system requires additional energy, off setting energy saved in ozone generation with the once through
system
The once through indirect cooling system employs a plate and frame heat exchanger between the ozone generator and
the open loop cooling water source. This protects the ozone generator from water quality issues while maintaining an
economical cooling system.
Spartan Environmental Technologies
Air and Water Treatment
Air and Water Treatment
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Spartan Environmental
Technologies, L.L.C.
7383 Lauren J Dr
Mentor, OH 44060
USA
Phone: 800-492-1252
Fax: 440-368-3569
E-mail: info@
spartanwatertreatment.com
Technologies, L.L.C.
7383 Lauren J Dr
Mentor, OH 44060
USA
Phone: 800-492-1252
Fax: 440-368-3569
E-mail: info@
spartanwatertreatment.com