Free Cooling Unit – Critical Control Forced Ventilation Unit

Free Cooling Unit 

Unit Assembly:
3 major parts:
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Inlet unit

Inlet unit consist of fixed louvers frame, filter, gravity louvers frame, rain canopy, mounting nut bolts, washers, spacers, screws, internal temp sensor (Thermo Couple).
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Outlet unit
Outlet unit consist of front & back fan frame, 48VDC fan, louvers frame, plastic louvers, their mounting nut bolts, spacers and external temp sensor PT 100 type with assembly.
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Controller
Controller is the microprocessor based electronic part of the unit. According to site conditions installation engineer/technician need to do setting at site
Unit Operation
General
Free Cooling Unit provides a free cooling solution for telecom sites which is efficient, energy saving and protects the environment. Free Cooling Unit is free from Freon gas and can endure long period service intervals. Free Cooling Unit is specially designed for easy installation in the existing telecom shelters
Free Cooling Unit obviates the need to cool hot air generated inside the telecom shelters and instead ensures effective outward transmission of the heat generated. The hot air gets displaced through an air outlet unit and the cool outside air is sucked-in through the air inlet unit filters. This provides an extremely reliable operational system.
Both the inlet and outlet air units are provided with rain canopies on the outside of the shelter. All the unit housings are fabricated from CRCA steel and powder coated. The air outlet unit is equipped with a prime quality axial flow fan, which is extremely reliable and has a high speed and high air flow volume. The fan has a long operational service life and works on 48 Volts DC power supply, with low energy consumption.
Free Cooling Unit is provided with its own intelligent micro-processor based controller unit with LED display and functional buttons, rendering it very easy to use. The controller continuously monitors the temperature inside the shelter and the ambient temperature outside the shelter.
The controller fully automatically controls the operation of Free Cooling Unit in all possible conditions in the telecom shelter in Auto Mode.
Normal Operation
The controller continuously monitors the real time temperature inside the shelter and ambient temperature outside the shelter, as well as the percentage relative humidity inside the shelter. The controller has the facility to set the normal operating temperature that needs to be maintained inside the shelter, normally which can be set between 22°C to 35°C as per the customer requirement. This is the shelter set point or the operating temperature, normally recommended to be set at 30°C. Whenever the outside ambient air temperature falls below the set point temperature by a pre determined value called ∆T [Settable between 20°C to 90°C normally set at 40°C] then the controller automatically switches off the air conditioners and starts the free cooling system. Under these conditions the Free Cooling Unit uses cool ambient air and maintains the shelter temperature at or below set point temperature. Subsequently whenever the shelter temperature rises above set point i.e. operating temperature, the controller will switch off the Free Cooling Unit system and switch on the air conditioners.
This system typically can save air conditioners energy in the range of 6 hours to 12+ hours per day depending upon the location and the season thereby contributing substantial saving in OPEX cost.
Emergency Cooling
The controller monitors required parameters and starts emergency operation. When Shelter temperature goes above emergency temperature set point OR mains power failure OR shelter temperature rises above Set point normally 35°C and shows temperature rising trend thereby indicating air conditioners failure.
During emergency cooling the shelter temperature will be maintained at about 3-4°C higher than ambient temperature. This emergency cooling operation is reset to normal cooling if shelter temperature is less than 34°C.
Additional Functionality
During free-cooling at any time if shelter temperature is lesser than the low shelter temperature set point (normally at 17°C) or if shelter humidity is greater than the set percentage relative humidity (Normally set at 80%), the free-cooling is disabled and air conditioners are enabled.