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Renewable-Energy Systems: Important Maintenance Practices
OTHER PARTS OF THIS ARTICLEPt. 1: Renewable-Energy Systems: Meet with Local Utility Pt. 2: This PagePt. 3: Product Focus: Energy Management
As engineering and maintenance managers are aware, all building systems and components need some level of maintenance, and renewable-energy systems are no exception to this rule. The specific maintenance requirements vary based on the type of system and components installed.
Manufacturers might claim their systems do not require maintenance, but if managers expect to get years of service and high-performance levels from their systems, technicians will have to perform all required maintenance activities on the systems.
For all renewable-energy systems, it is proper maintenance practice to inspect the integrity of mechanical and electrical connections at least once each year. Corroded or loose connections can result in decreased performance, and in extreme cases, they can create safety hazards.
Solar hot-water systems require periodic inspection of the panels for leaks, damage, and even build-up of dirt on panel surfaces. If the systems use a water-glycol mixture, technicians should test the system periodically for proper concentrations of glycol. They should inspect and test drain-down systems before the onset of cold weather to ensure the panels drain fully.
Solar electric systems also require periodic inspection of the panels for physical damage, dirt build-up, and proper tightness of the electrical connections. Technicians also should make certain vegetation growing near the installation does not block sunlight to the panels. Shadows that fall on even part of one panel can cause a significant reduction in the system's total output. Solar electric systems also require that technicians periodically test the output from system inverters.
Wind-turbine systems require similar testing and inspection of electrical connections and inverters. Technicians also should inspect all of the system's moving parts, including turbine blades and bearings, for damage at least once each year, according to manufacturer recommendations.
Geothermal systems have relatively low maintenance requirements, compared with other renewable-energy systems. Most geothermal systems use a water-source heat pump, in which the system circulates water through a loop buried in the ground.
The maintenance requirements parallel those for other heat-pump systems, with the exception of the buried loop. As long as workers install the system properly and nothing disturbs the ground in the area of the underground piping, no additional maintenance requirements should exist.
Systems that use large, standby batteries will have more maintenance needs. To date, most systems use lead-acid batteries. System operators must ensure the water level in these batteries remains at recommended levels to prevent battery damage.
Depending on the capacity of the batteries and their cycling frequencies, technicians should inspect them at least once each month. They also should keep records of the amount of water they add to each battery, because increased water use can indicate a particular battery is approaching the end of its service life.
It is equally important that technicians keep all electrical connections to the batteries clean and tight to prevent system losses and potential safety hazards.
Most manufacturers of renewable-energy systems offer a remote monitoring and management option with their systems. This feature allows manufacturers and in-house operators to track system performance and to identify potential system faults when, or even before, they actually occur. As a result, the monitoring systems can alert operators to maintenance requirements before they develop into larger, system-wide problems.
James Piper, P.E., is a national consultant based in Bowie, Md. He has more than 25 years of experience with facilities maintenance and engineering management issues.