Terminology and Definitions

Typical of any industry, the power generation industry is filled with acronyms and technical terms. Some of them are referenced in national standards, while others are little known except to those who deal in them on a regular basis. Below are some basic definitions that I am frequently asked about. I hope this helps!

Day Tank: a fuel containment system used to provide a close-proximity fuel supply source to boilers and diesel engines in power generation applications. Day tanks are typically installed between a large remote fuel storage tank and the boiler or prime mover. Typical features include a secondary containment basin to protect against fuel spills, a top-mounted fuel supply pump responsible for drawing fuel from a main storage tank, and various other electrical options to monitor and control fuel level and tank integrity. Depending on the site conditions such as the location of the main fuel storage tank (above grade or below grade), day tanks may also be equipped with multiple pumps to allow for excess fuel flow management and/or fuel return to main storage tank. Here are my Top-12 Recommendations for Day Tank Design.

Distributed Generation: refers to an electric power generation source that is located in close proximity to the consumer.  Diesel engine-generators, micro-turbines and solar power are examples.  Learn more here…

Exhaust System: a combination of items, integrated as a system, to provide for the reduction of noise and/or emissions produced by the exhaust gases of internal combustion engines. The main components are a silencer, engine exhaust flexible connector(s), insulation and accessories. Silencers are graded by their noise reduction ability: residential grade, critical grade, super critical grade, etc. Various silencer designs (cylindrical, hockey-puck, compact, etc.) are available to meet space and noise reduction requirements and they can also incorporate oxidation catalyst elements for emissions reduction. Flexible engine connectors are installed between the engine exhaust manifold and the silencer, and allow for the systems’ expansion and contraction resulting from operating temperature cycles. Insulation consists of thermal blankets installed on exhaust components to minimize radiated heat and potential hazard to operators and maintenance personnel. Accessories include tubing, wall thimbles, elbows, brackets and other components necessary for a complete and professional installation of the exhaust system.

Fireguard®: a trademark by the Steel Tank Institute for a “protected” above-ground fuel storage tank. This design offers 2-hour fire resistance, ballistic protection and impact protection. Tanks are listed to Underwriters Laboratories’ UL2085 standards, and built under STI license by independent fabricators in capacities up to 50,000 gallons.

Flameshield®: a trademark by the Steel Tank Institute for an above-ground fuel storage tank of 2-hour fire-resistant, double-wall construction. This design is tested by the Southwest Research Institute to SwRI 97-04, for 2 hours at 2000 F and built under STI license by independent fabricators in capacities up to 50,000 gallons.

Fuel Maintenance Systems: a system designed to maintain the integrity and stability of fuel that is stored for relatively long periods of time. The system’s main components include a circulating pump, electronic sensors and controller, water separator/filters and biocide agents. The circulating pump’s flow rate capability is selected according to the fuel storage tank’s capacity. The pump is activated on a pre-determined schedule or upon sensing of abnormal fuel conditions, to pickup fuel from the main storage tank, and circulate it through a combination of water separators and particle filters. Clean fuel is then returned to the main tank. Ninety-nine percent water removal and >2 micron particle removal is generally achieved. For control of organic matter (bacteria and fungi), a fuel-soluble biocide agent is introduced in the fuel storage tank, when needed. Sensors and control alarms are fitted to alert the system of abnormal conditions that require system activation.

Fuel/Oil Cooler: a heat exchanger device designed to remove excess heat from lube oil or diesel fuel. A fuel/oil cooler typically consists of a heat exchanger core, and a forced-air system that includes a fan and motor. These systems are generally stand-alone with frame and mounting provisions for floor installation. In some applications, a fuel/oil cooler will be limited to a heat exchanger core, installed on the engine radiator assembly to take advantage of the cooling airflow already created by the radiator fan. For lube oil applications, the lube oil cooler maintains the optimal oil temperature to maintain adequate viscosity and lubricity. For fuel cooling applications, the cooler is designed to accept the excess fuel that bypasses the engine’s fuel injection system. This fuel carries a higher temperature and must be cooled if it is to be returned to the engine’s primary fuel supply source. Higher temperature fuel will be less dense and will result in efficiency losses for the engine.

Fuel Port: a compact solution for filling of above-ground fuel storage tanks. A Fuel Port includes all valves and fittings necessary for hose connection from a pumper truck to an above-ground storage tank, packaged within a lockable, weatherproof spill containment box. Available in manual or automatic operation and also with a pump built-in (see SmartPump).

Fuel Storage Tank: also known as above-ground storage tanks (AST), provide for the principal containment of fuel on-site. Typical capacity for a main fuel storage tank is between 1,000 and 20,000 gallons. As one of the principal components of a fuel supply system, reliability and durability are the primary design criteria. Also, due to environmental and security concerns, many national and local codes require rupture leak detection and containment. A “protected” tank design requires not only rupture containment and fire resistance, but also ballistic and vehicle-impact resistance.

Load Bank: a device which develops an electrical load, which is then applied to an electrical power source (i.e.: generator set). The load bank then converts or dissipates the resultant power output of the source. A load bank is intended to accurately mimic the operational (or “real” load) which a power source will see in actual application. Unlike the “real” load, which is likely to be dispersed, unpredictable and random in value, a load bank provides a contained, organized and fully controllable load. Load banks can be designed to simulate resistive or reactive loads, and can be portable, stationary or duct-mounted.  Learn more here…

Neutral Grounding Resistor: used with 5kV and 15kV generator systems to limit destructive ground fault currents. They are typically inserted in the neutral-to-ground connection of 4-wire, wye-connected generator. Neutral grounding resistors are rated by their nominal operation voltage (L-N), the fault current value and withstand time value.

Radiator: a heat exchanger designed to remove heat generated by an engine and dissipated through a jacket water cooling circuit. Larger engines also incorporate aftercooler circuits to cool turbo air for recirculation into the combustion chamber. Radiators can be installed as “engine-mounted” units, which are driven by the engine crankshaft. They may also be installed remote from the engine, in either vertical or horizontal designs, when space, ventilation or noise limitations preclude installation near the engine. Typical engine and site data required for the proper selection of a radiator are: a) heat load data for all cooling circuits, b) circulation flow rate for all cooling circuits (i.e.: jacket water, aftercooler), c) estimated ambient temperature expected at radiator core, d) physical location of radiator in relationship to engine (horizontal and vertical references), and e) any special requirements for corrosion protection or wind-loading.

SmartPump: a Fuel Port with a built-in fuel transfer pump. The SmartPump is a factory-packaged system designed for safe transfer of fuel from gravity trucks to one or more storage tanks. Also allows control of filling operations to prevent overfill and allow for full draining of the truck’s delivery hose.

Waste Heat Recovery System: a system designed for the production of hot water or steam for use in commercial or industrial processes. Typical components for hot water service include a heat recovery assembly that circulates engine exhaust gases through tubes that are surrounded by the engine’s jacket water. The engine jacket water is heated and then circulated to the building process. This jacket water delivers its heat load and then returns to the engine to provide cooling before the process is repeated. In a steam service application, the engine exhaust gases are circulated through a heat recovery assembly to heat feedwater into low pressure steam. The steam is used in the building process and condensate returns to be used in the process again. Accessory components typically include bypass valves, pressure regulators, feedwater and deaerator tanks.

Not enough terminology? Feeling underwhelmed? EGSA’s Std. 101G, “Glossary of Electrical and Mechanical Terminology and Definitions” has many, many more terms for you. Grab a large cup of coffee and enjoy!

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