One of the aims of iSERV is that continuous monitoring and benchmarking of HVAC processes will provide energy saving benefits equivalent to or better than those achievable by physical inspection alone. The role of MacWhirter Limited in the project is to physically inspect some of the monitored system to compare the performance on site to the conclusions of the monitoring.
Picture: Inappropriate use of PTFE tape on this liquid valve showing presumption of refrigerant leakage.
All in all, there will be 80 iSERV-inspections throughout Europe. So far, Inspections have been carried out in Cardiff (UK) and Athens (Greece) on various types of systems and building sectors, but generally speaking no conclusions to our findings will be made until the comparisons are made after the monitoring and benchmarking period. However, as some of the systems were previously monitored for iSERV’s predecessor project (HARMONAC), we can see some early results. For instance, the system in an IT Server Room in the CUBRIC Building of Cardiff University was deemed by the HARMONAC Case Study to have issues with
a) the refrigeration circuits – in the main having signs being short of refrigerant and,
b) excessive electricity consumption from metering of the air conditioning.
Using a tactile approach to air conditioning inspection, problems with refrigeration circuits were established, during our inspection, which were confirmed from analyzing data from a ClimaCheck Performance Analyzer; and a good estimate of excessive electricity, through excessive compressor run time, owing to reduced performance (found by carrying out air side enthalpy checks) coupled with no reduction input energy, was determined from using both the ClimaCheck and current and voltage data loggers.
Our estimate from our short term measurements and an informed estimation of internal and external heat gains extrapolated to annual figures, as shown in the graph below) compare favorably with the meter monitoring of the HARMONAC Case Study which shows an unsatisfactory cooling EER of 1.43, thus, clearly proving the value of sub metering – providing the building owner reacts to it.
We were also able to show that with the permanent isolation of compressor crankcase heaters, controlled isolation of stand by units and repairs to the refrigeration circuits that the annual electricity consumption could be reduced to around 55,000 kWh, thus achieving an energy saving of 41%. The annual saving of electricity costs was estimated at around EUR 5,500 – well worth the investment in the metering and the four hour inspection.
Author:Dave Wright (MacWhirter)