Now that we know we need to measure temperature (water & outside air), water flow & kW we can start to gather our equipment.
Since the temperature range on a chiller is from as low as two to three degrees Fahrenheit, the accuracy of this device is critical . Typically wells are installed in the piping for dial or mercury based thermometers that can be removed for the installation of the temperature sensors.
Outdoor conditions need to monitored so that the load profile can be correlated to the weather. Since historical weather temperature data is available for most regions this correlation makes an excellent source to calculate the expected cost of operation of the system.
Another variation of this theory is: Does the load vary with the wet-bulb or dry-bulb temperature. Our finding typically indicate that commercial facilities follow the dry-bulb and industrial facilities and those using large quantities of outside air will follow the wet-bulb. Again this device needs high accuracy and should be shielded from solar radiation which can change the results.
Water flow is probably the most difficult of them all. Since there is typically no accurate flow meter installed internally in the piping system, we must now go to the external skin of the pipe to monitor the flow. A transit-time ultrasonic flow meter can be used here, which is totally external to the fluid in the pipe.
KW demand is the simplest, but by far the most dangerous. Never attempt to monitor electrical equipment without the proper training and protective equipment. Since it is typically impossible to turn this equipment off it must be worked HOT. Measuring amps is typically not acceptable, since the power factor (PF) of the motor will adjust the relationship of volts to amps based on the load. It is recommended that you use the same criteria for monitoring the power that the local utility does (demand, PF & etc.)
