How Energy Management Systems Work – Part 3

HVAC equipment health is an often-overlooked factor that has a major impact on costs, especially within multiple location operations.

Performance of an HVAC unit at a building degrades, for example, when a system refrigerant leak causes a compressor to overheat forcing other HVAC units to work harder to compensate for the loss of power from the weaker unit, increasing system load and total energy consumption. And since HVAC systems are inherently “dumb” and provide no warning of impending failure, a refrigerant leak or other problem in a defective HVAC unit will eventually cause the compressor to fail, leading to a $1,500-$2,000 repair cost when each failure occurs.

Based on our HVAC equipment monitoring experience, approximately 10% of all HVAC units in multi-location operations operate below their optimal level of performance at any given time, and a high number of these units are likely to fail within a short time period.

Since each building may have one or more HVAC units, this can add up to hundreds or thousands of HVAC units for a large operation—and a large capital repair cost liability, as sizable numbers of these units run to failure in any given year.  Repair expenses in the thousands, or hundreds of thousands of dollars annually are typical within a single operation.

But today, Real-time HVAC equipment monitoring and diagnostics for each HVAC system at every location are integrated into the overall energy management system.

With HVAC equipment monitoring, temperature sensors are installed at the inlet and outlet supply ducts for each unit, and data from each unit is continuously monitored and logged to the energy system database.

An operating performance profile for each and every individual HVAC unit in the entire base of HVAC units is then developed within the energy management system. Units operating at below average performance levels, based on predetermined values, can be flagged for a preventive maintenance call (at a cost of around $200). If no monitoring was in place, there would be no alternative for an HVAC unit other than “running to failure,” leading to a much more expensive repair cost (up to $2,000 or more per unit).