The APR Control provides capacity modulation for all sizes and configurations of air conditioning systems. By matching system capacity to continuously changing load conditions, the APR Control enhanced system is able to maintain better comfort conditions, as well as, provide a number of unique solutions that standard air conditioning systems (below 50 tons) are unable to achieve.

Air conditioning systems are primarily on/off devices of a fixed capacity, controlled by the limits of the thermostat. A standard thermostat, when set at 70 deg. F (with +/- 2 deg. F range), will turn the air conditioning on at 72 deg. F and cool the space, at full capacity, until the temperature is 68 deg. F and the thermostat is satisfied. This is repeated again and again. Standards for air conditioning design require that the air conditioning system have sufficient capacity to meet several design criteria (ie. Outdoor temperature, sunshine, internal occupancy and ventilation requirements). As most of these criteria are maximums for the peak of the summer, most of the time the system designed will be larger than necessary. When the system is oversized, the temperature may remain cool, but the system does not operate long enough to sufficiently dehumidify the space. The air conditioning system is "short cycling", meaning that for each 5 minutes the air conditioning system is actively cooling the space, there may be 20 minutes that the air conditioning system is merely recirculating air, not dehumidifying. During the off cycle the humidity level will rise and the combination of low temperature and high relative humidity can create an uncomfortable space.

An air conditioning system with the APR Control is a variable capacity system. The APR Control will allow the system to extend the cycle of operation, continuously matching the system capacity to the changing load conditions, while keeping the system in a dehumidifying mode. The net effect is that both temperature and humidity are more accurately maintained. The space is more comfortable as a result.

The APR Control has been applied to numerous air conditioning applications for a wide range of solutions. From residences to hospitals, paper mills to offices, computer rooms to manufacturing facilities, the APR Control has never failed to provide the solution.

 

return to top of page.

©2002 Rawal Devices. All rights reserved.