The Plaza Hotel has 4 chillers in their plant room. Two of their newest chillers, which were purchased and installed in 2011, were used for the CQM System tests. They are each 300 ton units made by Carrier. A table listing their properties can be seen below in Table 1.
The CQM System and data monitoring equipment were installed at the Plaza Hotel during the month of August 2012 (see Figure 2). The thermistors and flow meters were installed on August 8, 2012 for both systems. The split core current transformers were installed inside of the chiller’s electrical panels (See Figure 3).
Several issues were encountered during the installation. All eight thermistor signal wires were not long enough and each had extensions soldered to them. The data
logging system on Chiller 2 did not read its flow meter properly. Both systems did not communicate with their cellular modems nor did their cellular modems communicate with the local cellular provider. There was also what appeared to be a random ±0.5 degree Celsius drift in the temperature readings for all of the thermistors during their calibration in an ice bath.
The problem with Chiller 2’s flow meter reading stemmed from it being set up while the chiller was running. The CQM monitoring equipment required that a no flow situation be used to zero the measurement. The Proline Prosonic Flow 91W ultrasonic flow meter outputs a 4 to 20 mA signal to the CQM monitoring equipment (see Figure 5 and Figure 6).