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Michael K. West, Ph.D., P.E., Advantek Consulting Engineering |
The as-installed energy efficiency of unitary systems is much less than that of central systems, and the efficiency gap widens as systems age due to maintainability issues. Energy engineers and service technicians use indirect indicators of equipment performance and make adjustments according to manufacturer guidelines and standard field practice, which varies with technicians’ level of experience. Growing numbers of unitary systems combined with shrinking budgets result in deferred maintenance, and long-term operation of equipment at degraded levels. Energy efficiency is a metric that must be measured to be optimized. This paper reports on field testing of continuous sensing of actual operating energy efficiency to control unitary equipment operating parameters, provide remote fault detection diagnostics and support maintainability. The energy efficiency of most unitary HVAC systems is much less than chilled water systems and limited cost-effective choices exist for increasing their energy efficiency.