<![CDATA[Cooling tower is a system that serves water from the condenser to be discharged from the fan and then recirculated to the condenser so that the desired temperature in the room is reached. Whether or not water is cold in the cooling tower circulation depends on the level of water in each water cooling tower reservoir. The purpose of making prototypes is to facilitate human work to optimize water capacity so that it is not wasted or lacking water capacity so that it disrupts the condensation process in the cooling tower prototype. In this prototype used several hardware components namely Arduino UNO, ultrasonic sensors, motorized valves, DC pumps, relay modules and ESP-01 modules. This prototype communicates via blynk using an Android Smartphone. Periodic data can be displayed via an Android Smartphone. The ultrasonic sensor measurement results 1 and 2 for 5 minutes are 13.5 cm and 14.6 cm. While the average percentage accuracy of ultrasonic sensors 1 and 2 compared to the standard ruler measuring instrument is 98.57% and 97.7%. For the result data the average percentage of ultrasonic sensor error 1 and 2 is 1.48% and 1.53%. IoT communication can be monitored properly at a distance of 16 km and 34 km by connecting to a stable internet connection. The benefits of this research are expected to provide the effectiveness of the work by minimizing the use of wasted water due to unequal water levels. Keywords: Cooling Tower, Ultrasonic Sensor, Motorized Valve, Arduino, Android]]>
