Note: This report was sent before the discovery of the uselessly running squirrel cage blower on the roof the afternoon January 4, 2006 - and more discoveries may yet be made.
You may also wish to view Ron's earlier efforts Ron Crane Power Sept 2005 which improved things before the measurements below. These efforts reduced the reheat cycling and various other optimizations.
Ed,
Alberto Delgadillo arranged for me to meet with Brian from the HVAC maintenance co. on Dec. 22, 2005. The purpose was to determine if we can increase the airflow through the 1401 room allowing us to shut off the Liebert unit except when the 1401 is running. He said the main building system is shut down at 6:00 pm. after which time we would need some alternate method of cooling. Further discussion was postponed until January when everyone was back.
Also, service for the "compressor 1 low suction" alarm needs to be handled during the January scheduled maintenance. The system will only use compressor 2 until then. Normally it alternates between the two.
We did disable the humidifier, dehumidifier, and heater functions and increase the temperature setting. Thus only the 5.77KW ($7,000/yr. @ .14/KWH) fan motor runs continuously and the compressor comes on only if the temperature goes above 75 degrees F.
I monitored the hours of operation of the various components (fan motor, compressors, and reheat elements) by recording the run hours from the system panel on various dates. Costs are are based on the average of past museum electric rates of .14/KWH (.11/KWH winter & .17/KWH summer). The annualized rates assume the whole year had the same usage pattern as the period measured. Below are 2 sample periods with some overlap. The reheat coil hours for the week of Sept 14-21 were 145 compared to 139 for the period from Oct. 26 to Dec. 21. Reheat is part of dehumidify function.
| Time Period | 9-14 to 10-26 | 9-21 to 12-21
| Indoor fan 5.77KW | 5,908 KWH | 12,786 KWH
| Compressor 8.49KW | 5,569 | 9,025
| Condenser fan 3.1KW | 2,034 | 3,295
| Reheat coil 8.82KW | 6,765 | 6,712
| Total KWH | 20,276 | 31,818
| # days | 42 days | 91 days
| total $ @ .14/KWH | $ 2,839 | $ 4,454
| Annualized | $ 24,669 | $ 17,865
| |
- Ron