4. Lower air density can also become challenging when designing gas compressors. At sea level, specifying the flow in cubic feet per minute (CFM) or in standard cubic feet per minute (SCFM) is innocuous since their values are approximately equal. However, at high altitude, the difference between actual CFM (ACFM) and SCFM becomes quickly significant. Therefore, if this aspect is not clarified with the manufacturer, it may lead to the wrong compressor sizing and selection.
5. The higher the altitude, the more significant the gap is between relative and absolute pressure, especially when pumping fluids. Thus, proper attention has to be given to the “near to” or “at saturation” level fluids, along with their thermodynamical properties at different pressures and temperatures (e.g., water flashing into steam, pump cavitation) to avoid any unwanted fluid state in the plant process.
6. Along the same lines, carrying fluids in a closed circuit requires special attention when designing the expansion tanks. For instance, manufacturers typically pre-pressurize diaphragm expansion tanks to one (1) ATM. But naturally, in a high-altitude application, this variable needs to be carefully calculated, while considering high and low network points, and validated with the manufacturer before final selection of the equipment.
7. Typical generating sets come with integrated engine-driven oil pumps for the crankshaft and other engine components lubrication. These pumps are usually designed to operate at sea level, but failing to adapt crucial design variables to high altitude (e.g., net positive suction head) can lead to oil foaming in the crankcase. Accumulation of formed air bubbles in the oil may then cause pump failure or more severe consequences. In one of our applications for instance, the pump had to be deported from the engine onto a separate skid for proper functioning.
8. When air is used as electrical insulation for electrical equipment (e.g., generators, cable terminal boxes, dry type transformers, high-voltage cables and even computer hard drives), air clearance between live parts at high altitude must be revised and the appropriate derating factor must be applied to ensure proper insulation between components. This clearance can then increase by a factor of up to 1.4.
9. The human factor also needs to be considered when at high altitude, as productivity levels decrease in conjunction with oxygen levels. This aspect can quickly involve financial challenges if not factored into the budget. Moreover, scarcity of specialized personnel becomes challenging, especially when considering site remoteness.
10. Additionally, and depending on plant remoteness, logistical complexities (e.g., schedule of equipment delivery on site, transport, installation, etc.) must be correctly assessed to avoid any schedule delays. As a result, prefabricated skids are encouraged for this type of application.