Ra Power & Light

A

Accessible

Readily. Having direct access without the need of moving or removing any panel, door or similar covering of the item described.
Reasonably. Having access to, but which first may require the removal of a panel, door or similar covering of the item described.

Activation

Chemical. Treatment of a substance by heat, radiation, or other activating reagent to produce a more complete or rapid chemical or physical change.
Electrical. The process of treating a cathode to increase its rate of reduction.

Activation Polarization - Activation Polarization is present when the rate of electrochemical reaction at an electrode surface is controlled by sluggish electrode kinetics. This is similar to chemical reactions where the reacting species must overcome an activation barrier. For fuel cells, this region is characterized by a drop from the theoretical EMF or ideal voltage prior to electron or ion flow.

Air - The mixture of oxygen, nitrogen and other gases which, with varying amounts of water vapor, form the atmosphere of the earth. Also referring to any or all air for combustion, heating, cooling, ventilation and other uses as follows:

Ambient- Air that surrounds the equipment.
Atmospheric- Air under the prevailing atmospheric conditions.
Combustion- Air required for safe and proper combustion of fuel gas.
Dilution- Air which enters a draft regulator or similar device and mixes with the flue gases.
Excess. Air which passes through the combustion chamber and any flues in excess of that which is theoretically required for complete combustion.
Exhaust- Air removed from a space and not reused.
Outdoor- Air taken from the outdoors and, therefore, not previously circulated through the system.
Primary- Air introduced into a burner at the mixer head, which mixes with the gas before reaching the port(s).
Recirculated- Air removed from a space and intended for reuse as supply air.
Return- Air removed from a space and recirculated or exhausted.
Secondary- Air externally supplied to the flame at the point of combustion.
Standard- Air at standard temperature and pressure, namely 70°F (21°C) and 29.92 inches (760 mm mercury column, having a specific weight of 0.075 pounds per cubic foot (1.20 3kg/cu m). [Indicates a temperature of 70°F (21°C). The ISO standard (59°F) might be more appropriate to allow direct comparisons with turbines].
Supply- That air delivered to each or any space in the system or the total delivered to all spaces in the system.
Ventilation- That portion of supply air which comes from the outside (outdoors) plus any recirculated air that has been treated to maintain the desired quality of air within a designated space.

Agency Approvals – Federal, State and local Utility regulations determining construction processes, safety guidelines, specific components, use, design configuration and operation of renewable energy systems. Construction Permits are filed with local municipalities who perform field inspections in each stage of construction to assure compliance with OSHA safety standards and best practices in electrical engineering design and implementation. Completed systems must be in full compliance with all regulatory requirements to operate, and allow system owners to become eligible for Federal, State and local tax incentives.

Air Inlet, Primary - The opening(s) through which primary air is admitted into a burner.

Air Shutter - An adjustable device for varying the size of the air inlet(s) regulating primary or secondary air. Automatically-Operated. An air shutter operated by an automatic control.

Alkalline Fuel Cell (AFC) - A type of hydrogen/oxygen fuel cell in which the electrolyte is concentrated KOH (varies between 35 to 85 wt% depending on the intended operating temperature) and hydroxide ions (OH-) are transported from the cathode to the anode. Temperature of operation can vary from <120°C to approximately 250°C depending upon electrolyte concentration.
Anode reaction: H2 + 2OH- ® 2H2O + 2e-
Cathode reaction: ½O2 + H2O + e- ® 2OH
Overall reaction: H2 + ½O2 ® H2O.

Anaerobic Bacteria- are an integral component of nature’s waste management and are commonly found in soils and deep waters, as well as in landfill sites.

Anaerobic Digestion (AD) - is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen into useful biogas.. It is widely used to treat wastewater sludges and organic waste because it provides volume and mass reduction of the input material. As part of an integrated waste management system, anaerobic digestion reduces the emission of landfill gas into the atmosphere. Anaerobic digestion is a renewable energy source because the process produces a methane and carbon dioxide rich biogas suitable for energy production helping replace fossil fuels. The breakdown of organic compounds is achieved in a soup of many types of bacteria including those that generate carbon dioxide and methane- acetogenic and methanogenic bacteria respectively. These bacteria function at two optimum temperature ranges, 35-39°C (mesophilic) and 55-60°C (thermophilic). Organic waste is broken down into sugars and amino acids by enzymes similar to those that help digest our food. These are then fermented to produce volatile fatty acids and converted by acetogenic bacteria in to hydrogen, carbon dioxide and acetate. Finally methanogenic bacteria produce biogas, a mixture of carbon dioxide (40%) and methane (60%) and other trace elements.

Anode - The electrode at which oxidation occurs. For cells that create potential, it is also the electrode towards which the negative ion flows.

Appliance - Any device which uses energy to produce light, heat, power, refrigeration or air conditioning (See Gas Utilization Equipment).

Appliance, Cogeneration - A self-contained, fueled appliance providing electrical energy and thermal energy to be used remote from or adjacent to its location.

Appliances, Automatically-Controlled - Appliances equipped with automatic devices which (1) accomplish complete “turn-on” or “shut-off” of the fuel to the main point of consumption or (2) graduate the gas supply to the main burner, but do not affect complete shutoff of the gas.

Approved - Acceptable to the authority having jurisdiction.

Architectural Renderings - Ra Power & Light CAD Drawings ad blueprints of proposed system design(s) integrated with the site.

Authority Having Jurisdiction - The organization, office or individual responsible for “approving” equipment, an installation or a procedure.

Auxiliary Power - Power from an independent source that functions as required to augment/support various performance criteria established for the prime power source.

Availability - A factor based on the ratio (%) of a power source's fully operational hours (the number of hours that the power source is operating and producing power) divided by the total planned/expected hours of full operation.

Availability Factor - The ratio of the time a generating unit or piece of equipment is ready for, or in service to, the total time interval under consideration.

B

Back Pressure - Pressure against which a fluid or gas is flowing, resulting from friction in lines, restrictions in pipes, valves, pressure in vessel to which fluid is flowing, hydrostatic head, or other impediment that causes resistance to fluid flow.

Baffle - An object placed in an appliance to change the direction of or retard the flow of gas, air, gas air mixtures, or flue (exhaust) gases.

Baffle, Flue Gas - An object in the path of the flue gases and exposed to flue gases or radiant heat, which is intended to restrict or modify flue gas flow. It may be a projection from the heat exchanger or suspended in the flue gas passages by some other means.

Load-Bearing. A flue gas baffle which adds support, strength or rigidity to a heat exchanger or flue.
Non-load-Bearing. A flue gas baffle, which does not add support, strength or rigidity to a heat exchanger or flue.

Balance-Of-Plant - Supporting/auxiliary components based on the power source or site-specific requirements and integrated into a comprehensive power system package centered on the power source.

Base - The lowest frame or structure of the appliance, exclusive of legs that provides the primary means of support.

Base Load - The constant electrical demand by a system to a power supply.

Battery Maintenance – a standard maintenance procedure in renewable energy systems.

Bearing, Oilless - A sleeve bearing of porous material that depends solely on the porosity of the metal to store oil.

Bipolar Plates - Conductive plate in a fuel cell stack that acts as an anode for one cell and a cathode for the adjacent cell. The plate may be made of metal or a conductive polymer (which may be a Carbon-filled composite). The plate usually incorporates flow channels for the fluid feeds and may also contain conduits for heat transfer.

Black Start - A power source’s ability to power up from a cold shut down condition to fully operational status through a dedicated auxiliary power source that is totally independent of external systems.

Blowdown - The difference between the opening and closing pressures of a relief/safety valve.

Blower - A fan used to force air and/or gas under pressure.

Boost Regulator - Voltage conversion device used to raise the voltage in a DC system.

British Thermal Unit (BTU) - The mean British Thermal Unit is 1/180 of the heat required to raise the temperature of one pound (1lb) of water from 32°F to 212°F at a constant atmospheric pressure. It is about equal to the quantity of heat required to raise one pound (1 lb.) of water 1°F.

Burner - A device for the final conveyance of the gas, or a mixture of gas and air, to the combustion zone (See Main Burner).

Forced-Draft. A burner for which air for combustion is supplied by a fan ahead of the gas utilization equipment.
Induced-Draft. A burner which depends on the draft induced by a fan beyond the gas utilization equipment for its proper operation.
Injection “Bunsen, Type. A burner employing the energy of a jet of gas to inject air for combustion into the burner and mix it with the gas.
Injection Type, Atmospheric. A burner in which the air at atmospheric pressure is injected into the burner by a jet of gas.
Luminous or Yellow-Flame. A burner in which secondary air only is depended on for combustion of the gas. Power. A burner in which either gas or air, or both, are supplied at pressures exceeding the line pressure for gas and atmospheric pressure for air, this added pressure being applied at the burner.
Premixing. A power burner in which all or nearly all of the air for combustion is mixed with the gas as primary air.
Pressure. A burner which is supplied with a gas-air mixture under pressure, usually from 0.5 to 14.0 inches water column (1/8 to 3.5kPa) and occasionally higher.

Burner, Automatically-Lighted - One where gas to the main burner is normally turned on and ignited automatically.

Burner Head - That portion of a burner beyond the outlet end of the mixer tube that contains the ports.

C

Capacity Factor - The ratio of the average power load of an electric power source to its rated capacity over a selected period of time (Also known as “plant factor”).

Capital Recovery Factor - An accounting method for recognizing the time value of money in the analysis of various investment options. The factor will vary depending on the type of investment, type of calculation and the parameters that a company or individual enforces to reflect the risk of an investment.

Catalyst - A chemical substance that increases the rate of a reaction without being consumed; after the reaction it can potentially be recovered from the reaction mixture chemically unchanged. The catalyst lowers the activation energy required, allowing the reaction to proceed more quickly or at a lower temperature.

Catalyst Coated Membrane (CCM) - Term used to describe a membrane (in a PEM fuel cell) whose surfaces are coated with a catalyst layer to form the reaction zone of the electrode (See Membrane Electrode Assembly [MEA].)

Catalyst Loading - The amount of catalyst incorporated in the fuel cell per unit area. Typical units are mg/cm2.

Cathode - The electrode at which reduction occurs.

Cell Types

Active Area. The surface area of an individual cell that is available for chemical reaction. The active area is typically less than the total area of a cell to accommodate cooling, distribution and sealing mechanisms.
Components. The substructures within a cell that support the reaction, provide physical structure, receive and distribute reactants, remove products, dissipate heat, and perform other functions necessary for operation.
Coolant. A liquid or gaseous substance provided to or around the cell to remove heat produced by the cell’s operation and to maintain the optimum operating temperature of the cell.
Degradation Rate. The rate at which a cell’s performance deteriorates over time. The degradation rate can be used to measure both recoverable and permanent losses in cell performance. The typical unit of measure is volts (dc) per unit time.
Internal Resistance Loss. The loss in cell performance due to resistance losses caused by internal structures that create resistance to electron or ion flow. The most noticeable impact is seen in the cell’s operating region that occurs after activation, but before concentration polarization occurs. (See Activation, Ohmic and Concentration Polarization)
Life. The length of time that a cell can be used to produce useful amounts of power.
Power Density. The amount of power produced per unit measure. For a single cell, this is typically measured as kW per square centimeter or meter.
Pressure Differential. The difference in pressure across the electrolyte as measured from one electrode to the other.

Circuit, Electric

High-Voltage. A circuit operating at more than 600 volts nominal.
Low-Voltage. A circuit at voltages from 31 to 600 volts inclusive.
Extra-Low-Voltage. A circuit operating at a voltage up to and including 30 volts. Definitions for “High-Tension”, “High-Voltage” and “Low-Voltage” conflict with the commonly accepted utility definitions for these terms.)

Circuit, Safety-Control - A circuit or portion thereof involving one or more safety controls aimed at preventing unsafe operation of the controlled equipment due to grounding, opening or shorting of any part of the circuit.

Circuit Testing – a standard maintenance procedure in renewable energy systems.

Coal Gas – A fuel gas obtained through the carbonization (distillation by heat in the absence of air) of coal. Typical coal gas mixtures include high concentrations of hydrogen and carbon monoxide.

Cogeneration - The simultaneous on-site production of electric energy and process steam or heat from the same power source.

Combustion - The rapid oxidation of fuel accompanied by the production of heat, or heat and light.

Combustion Chamber - The portion of an appliance within which combustion occurs.

Combustion Products - Constituents resulting from the combustion of a fuel with oxygen. For combustion processes that obtain oxygen from air, this includes the inerts contained in air but excludes excess air used in the combustion.

Comprehensive Energy Audit (CEA) is a value assessment and technology road map to remain grid connected or for grid independence. The goals of the CEA are to verify each site’s ability to produce energy, set the logical order of proposed energy services and prove the financial viability of the project itself. The CEA includes detailed system designs, costs and ROI analysis.

Compression - A system of forces that reduces the volume occupied by a specific quantity of gaseous material.

Compressor - A device used for increasing the pressure and density of gas. (See Turbocharger).

Compressor, Fuel Gas - A pump or machine for reducing the volume and increasing the pressure of fuel gas.

Condensate (Condensation) - The liquid that separates from a gas (including flue gases) due to a reduction in temperature.

Control, Point Of -

Cut-Off. The temperature at which a control acts to shut off the gas to the main burner.
Cut-on. The temperature at which a control acts to turn on the gas to the main burner.

Controls - Devices designed to regulate the fuel, air, water or electrical supplies to the controlled equipment. These may be manual, semi-automatic or automatic.

Combustion. A control which automatically regulates the firing rate at predetermined air-fuel ratios in accordance with load demand.
High-Low Firing. The action of a combustion control which positions the air and fuel supply for low-fire and for high-fire in accordance with load demand.
Modulating. The action of a combustion control which gradually varies the air and fuel supplies within limits in accordance with load demand.
Limit. A control that automatically responds to changes in temperature, pressure, flow or level for limiting the operation of the controlled equipment. This device is not considered an operating control.
Operating. A control, other than a safety control or interlock, to start or regulate equipment operation according to load demand and to stop or regulate equipment operation on satisfaction of demand or upon reaching normal temperature or pressure in the equipment being operated. An operating control also may actuate auxiliary equipment.
Safety. Automatic controls and interlocks (including relays, switches, and other auxiliary equipment used in conjunction therewith to form a safety-control system) which are intended to prevent unsafe operation of the controlled equipment.
Safety, Primary. A control responsive directly to flame properties; sensing the presence of flame and causing fuel to be shut off in the event of ignition or flame failure requiring manual reset.

Controls, Fuel - Devices designed to regulate the fuel supply to the controlled equipment. These may be manual, semi-automatic or automatic.

Control Systems- Ra Power & Light Designed Intelligent electronic devices used for system operation, control, monitoring and measurement.

Control System Design - See Control Systems

Convection - The circulatory motion that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity. Generally fluid flow occurs because of natural convection (convection caused by density gradients), and forced convection (convection enhanced by mechanical means), and may be characterized by stagnant regions, laminar flow and turbulent flow.

Coolants - A fluid used to affect heat transfer among various mediums.

Nontoxic. Transfer fluids having a Gosselin rating of one (1), including water, propylene glycol, mineral oil, polydimethyoil oxane, Freon and FDA-approved water additives. Such fluids are deemed essentially nontoxic by the BOCA Basic/National Plumbing Code or GRAS (generally recognized as safe) by the FDA (Food and Drug Administration).
Toxic. Transfer fluids having a Gosselin rating of two (2) or more, including ethylene glycol, hydrocarbon oils, ammonia refrigerants and hydrazine. Such fluids are deemed essentially toxic by the BOCA Basic/National Plumbing Code.

Cost / Benefit Analysis - See Energy Audits

Counter Flow - A flow in opposite directions in adjacent parts of an apparatus, as in a heat exchanger.

Cross Flow - A flow going across another flow at an angle essentially perpendicular to one another.

Cubic Foot, Standard - The amount of gas, saturated with water vapor, which would occupy one cubic foot when at a temperature of 60°F and under an absolute pressure of 30 inches mercury column.

Cubic Meter, Standard - The amount of dry gas that would occupy one cubic meter when at a temperature of 15°C and under an absolute pressure of 760 millimeters (mm) mercury column.

Current Collector - Term used to describe the conductive material in a fuel cell that collects electrons (on the anode side) or disburses electrons (on the cathode side). The current collectors are micro porous (to allow for fluid flow through them) and lie in between the catalyst/electrolyte surfaces and the bipolar plates.

Current Density - A vector-point function describing the magnitude and direction of charge flow per unit area, generally expressed in amperes per square meter.

Custom Parts - Parts designed by Ra Power & Light to improve operating efficiency of renewable energy systems.

D

Desulfurizer - A component for removing sulfur from a fuel mixture.

Diffusion - Movement of a species under the influence of a gradient of chemical potential (i.e. a concentration gradient).

Direct Internal Reforming - Production of a desired product (hydrogen) within a fuel cell from a hydrocarbon based fuel (methanol, gasoline, etc.) fed to the fuel cell or stack.

Direct Methanol Fuel Cell (DMFC) - A type of fuel cell in which the fuel is methanol (CH3OH), in gaseous or liquid form. The methanol is oxidized directly at the anode with no reformation to hydrogen. The electrolyte is typically a PEM.
Anode reaction: CH3OH + H2O ® CO2 + 6H+ + 6e-
Cathode reaction: 6H+ + 3/2O2 + 6e- ® 3H2O
Overall reaction: CH3OH + H2O + 3/2O2 ® CO2 + 3H2O

Discretionary Downtime - A period during which equipment is not operating because of the operator’s choice, rather than equipment failure.

Distributed Generation - Any small-scale power generation technology that provides electric power at or closer to the customer’s site than centrally sited generation stations.

Distillate - A product formed by heating a liquid in a vessel and collecting and condensing the resulting by-product(s).

E

Efficiency - A measure (usually a ratio) of the useful energy provided by a dynamic system versus the total energy supplied to it during a specific period of operation.

Effluent - The products of combustion plus the excess air discharged from gas utilization equipment (See Flue Gases).

Electrical, Current - The net transfer of electric charge per unit time; expressed as amperes.

Electrical, Power Factor - See Power Factor

Electrical, Single Phase - A circuit energized by a single alternating electromotive force.

Electrical, Three Phase - A combination of three circuits energized by alternating electromotive forces that differ in phase by one third of a cycle.

Electrical Diagrams -

Connection. A diagram showing the connections of an installation or its component devices or parts. It may cover internal or external connections, or both, and contains such detail as is needed to make or trace connections that are involved. The Connection Diagram usually shows general physical arrangement of the component devices or parts.
Schematic. A diagram showing, by means of graphic symbols, the electrical connections and functions of a specific circuit arrangement. The Schematic Diagram facilitates tracing the circuit and its functions without regard to the actual physical size, shape or location of the component devices or parts.
Schematic - Ladder Form. A diagram drawn in the form of a vertical ladder. The outer vertical lines represent the electrical supply conductors. The horizontal steps represent each individual circuit with all component devices or parts.

Electrical Efficiency - The ratio of useful electrical real power output to the total electrical power input.

Electrical Equipment - See Equipment, Electrical

Electrical Transient - Any voltage or current that deviates from the normal steady-state condition.

Lightning Transient. Any voltage or current which deviates from normal steady-state conditions due to electrical disturbances in the atmosphere. Line Transient. Any voltage or current which deviates from normal steady-state conditions due to collapsing magnetic fields, solid-state switching, motor or inductive inrush, or momentary power losses. Static Voltage. The voltage created by the buildup of static charges on people or objects.

Electrode - An electric conductor through which an electric current enters or leaves a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.

Electrode Assembly - The portion of an automatic ignition system containing the electrode(s) and associated insulators, wire lead terminals, spark gap adjustment means and mounting brackets.

Electro-Osmotic Drag - The flux of a polar species (H2O) due to its attraction to a proton (H+) that is transported from the anode to the cathode.

Electrolyte - A non-metallic electrical conductor in which current is carried by the movement of ions.

Element, Heating - All parts which transmit heat from flames or flue gases to the medium being heated and in contact with both.

Element, Thermally-Actuated - That part of a control device which is directly acted upon by temperature changes and originates or supplies motion or energy directly or indirectly to operate a control device (valve, switch, etc.).

Energy Audit –A completed value assessment and technology road map to take large-scale facilities (U.S. Military Bases, Detention Centers and Process Industries) entirely off the grid- or remain grid connected. The goals of Ra Power & Light Energy Audits are to measure the ability of each location to produce energy, set the logical order of proposed Energy Services and prove the overall financial viability of the project.

Environmental Regulations – See Agency Approvals

Equipment, Electrical - A general term including material, fittings, devices appliances, fixtures, apparatus and the like used as part of, or in connection with, an electrical installation.

Equivalence Ratio - The ratio of the stoichiometric oxidizer to fuel ratio (O/F) of a particular oxidizer and fuel to the actual oxidizer to fuel ratio at which the unit is operating. This is a measure of the “fuel rich” condition of a system (ER>1 is fuel rich while ER<1 is fuel lean). For example, in a pure oxygen and hydrogen system, the stoichiometric O/F is 8:1. Therefore, a unit operating at a ratio of 4:1 has an equivalence ratio of 2.0 (fuel rich).

Exhaust Heat - Waste heat produced by a mechanical, chemical, or electrochemical process.

Exhaust Heat Recovery - The use of by-product heat as a source of energy.

External Reforming - The production of hydrogen from a hydrocarbon fuel (methanol, gasoline, natural gas, propane, etc.) prior to entry to the fuel cell or stack.

F

Failure Analysis - Tests determining the root cause(s) of a system fault.

Failure Modes And Effects Analysis (FMEA) - A structured process of analysis to identify and classify concerns, features and reasoning, and to recommend corrective actions for as many potential failures as is reasonably possible.

Fan - A device consisting of a rotor and housing for moving air or gas at relatively low pressure differentials.

Fault Detection - a standard maintenance procedure in renewable energy systems, automated through the use of control systems.

Feasibility Energy Audit (FEA) is a high-level scoping document produced after analyzing a combination of utility spend and all sites proposed.

Feasibility Studies - See Energy Audits

Filter - A device intended to remove solid material from a medium, such as air or fluid.

Flame Safeguards – See Contols

Flat Plate Cells - Fuel cells that are structurally planar.

Flue (Exhaust) - The general term for the passages and conduits through which flue gases pass from the combustion chamber to the outer air. Appliance-The passage(s) within an appliance through which combustion products pass from the combustion chamber of the appliance to the outlet of the appliance. Chimney-The passage(s) in a chimney for conveying the flue or vent gases to the outside atmosphere.

Flue Collar - A projection or recess provided to accommodate the vent connector.

Flue Gases - Products of combustion plus excess air in appliance flues or heat exchangers.

Flue Losses - The sensible heat and latent heat above ambient temperature of the flue gases leaving gas utilization equipment.

Flue Outlet - The opening provided in gas utilization equipment for the escape of the flue gases.

Fluid - Any substance that can flow, liquid or gas.

Fluid, Heat Utilization - A heat transfer fluid that takes thermal energy from heat exchangers and transfers it to customer equipment supplying hot water, space heating and other thermal loads.

Forced Derating Hours - Time that is measured in hours that a generating unit is required to operate at less than full power because of a maintenance or operating problem. This reduction in power level is not voluntary and cannot be delayed.

Forced Outage - A power outage that results from the failure of a system component requiring that the power system be taken out of service immediately, either automatically or manually. Also an outage caused by improper operation or human error.

Forced Outage Rate - The mean number of failures of a component per unit exposure time. Usually exposure time is expressed in years.

Fuel - A material used to create heat or power through chemical conversion in processes such as burning or electrochemistry.

Fuel Cell - An electrochemical device that continuously converts the chemical energy of a fuel and an oxidant to electrical energy. The fuel and oxidant are typically stored outside of the cell and transferred into the cell as the reactants are consumed (See Reversible Fuel Cell, PEMFC, SOFC, MCFC, PAFC, and DMFC).

Fuel Gas Compressor – See Compressor, Fuel Gas

Fuel Gas Controls – See Controls, Fuel Gas

Fuel Utilization - In fuel cells, the fraction of the fuel or oxidant that enters the cell that reacts electrochemically.

Fusible Plug - A device which opens and keeps open a relief vent by the melting or softening of a fusible plug or cartridge at a predetermined temperature.

G

Gas - Fuel gas, such as natural gas, undiluted liquefied petroleum gases (vapor phase only), liquefied petroleum gas-air mixtures, or mixtures of these gases

Liquefied Petroleum Gases. Liquefied Petroleum Gases, "LPG", as used in this standard, shall mean and include any material which is composed predominantly of any of the following hydrocarbons, or mixtures of them: propane, propylene, butanes (normal butane or isobutane) and butylenes.
LP Gas-Air Mixture. Liquefied petroleum gases distributed at relatively low pressures and normal atmospheric temperatures which have been diluted with air to produce desired heating value and utilization characteristics.
Natural Gas. Mixtures of hydrocarbon gases and vapors consisting principally of methane (CH4) in gaseous form.
Normal Butane (n-Butane), technical Grade. A liquefied petroleum gas composed of a minimum of 95 percent n-butane (C4H10) which may contain other impurities such as isobutane, butylenes and propane not in excess of 5 percent.
Propane MD-5. A special grade of liquefied petroleum gas composed of a minimum of 90 percent liquid volume of propane (C3H8) and a maximum of 5 percent liquid volume of propylene (C3H6).

Gas Cleanup - Removal of a contaminant from gaseous feed streams by a mechanical or chemical process.

Gas Turbine - A turbine rotated by expanding gases.

Gas Utilization Equipment - Any device which utilizes gas as a fuel or raw material, or both (also see Appliance).

Gas Vent - A passageway, composed of listed factory-built components assembled in accordance with the terms of listing, for conveying flue gases from gas utilization equipment or their vent connectors to the outside atmosphere (See Vent).

Governor, Zero - A regulating device that is normally adjusted to deliver gas at atmospheric pressure within its flow rating.

Grid Connected - A power delivery method that utilizes an independent power source which normally operates in parallel with a utility power system.

Grid Integration - the interconnection between renewable power generation systems and conventional public sources of electricity.

Grid Isolated - A power delivery scheme consisting of an independent power source that serves a dedicated load and is not interconnected with the utility power system.

Gross Power - The fundamental power output of an energy source prior to any conditioning and losses associated with the production of power suitable for the connected load.

H

Hazardous Location - See Location, Hazardous

Heat Exchanger - A vessel in which heat is transferred from one medium to another.

Heating Value (Total) - The number of British Thermal Units (BTU’s) produced by the combustion of one cubic foot of gas at constant pressure, when the products of combustion are cooled to the initial temperature of the gas and air, when the water vapor formed during combustion is condensed, and when all the necessary corrections have been applied.

Lower (LHV). The value of the heat of combustion of a fuel as measured by allowing all products of combustion to remain in the gaseous state. This method of measure does not take into account the heat energy put into the vaporization of water (heat of vaporization).
Higher (HHV). The value of the heat of combustion of a fuel as measured by reducing all of the products of combustion back to their original temperature and condensing all water vapor formed by combustion. This value takes into account the heat of vaporization of water.

Hydrocarbon - A chemical compound consisting of hydrogen and carbon formed in a variety of bond structures, such as oil, methane, propane, butane, etc.

I

Idle Power - The system rate of doing work when only the minimum work rate is employed by the system.

Idle Time - The time when a system is capable of but not producing power; startup time.

Igniter - A device that utilizes electrical energy to ignite gas at a pilot burner or main burner.

Ignition, Automatic - Ignition of fuel at the burner when the fuel controlling device is turned on, including reignition if the flames on the burner have been extinguished by means other than by the closing of the fuel controlling device.

Ignition Device - A device for igniting fuel at a burner. It may be a pilot or an igniter.
Direct. An igniter utilized to ignite gas at a main burner.

Ignition Source

Continuous. An ignition source which, once placed in operation, is intended to remain ignited or energized continuously until manually interrupted.
Intermittent/Continuous. An ignition source which is ignited or energized upon equipment user initiation of the operation cycle and which remains continuously ignited or energized during the equipment use cycle. The ignition source is extinguished or de-energized when the equipment use cycle is completed.
Intermittent. An ignition source which is automatically ignited or energized when the equipment is called on to operate and which remains continuously ignited or energized during each period of main burner operation. The ignition source is automatically extinguished or deenergized when each main burner operating cycle is completed.
Intermittent/Interrupted. An ignition source which is ignited or energized upon equipment user initiation of the operational cycle and which is extinguished or de-energized after the equipment use cycle has been initiated.
Interrupted. An ignition source which is automatically ignited or energized when the equipment is called on to operate and which remains ignited or energized during the main burner Flame-Establishing Period. The ignition source is automatically extinguished or deenergized when each main burner Flame-Establishing Period is completed.

Ignition System

Direct. A system in which the ignition means functions to ignite the main burner gas directly and in which a flame sensing means or safety shutoff device senses main burner flames or the absence of main burner flames.
Indirect. A system in which the ignition means functions to ignite the main burner gas and the igniter sensing device proves the ability of the ignition means to ignite the main burner gas.
Intermittent. A system in which the ignition source is automatically shut off when the equipment is in an off or standby condition.

Ignition System, Automatic - A system designed to ignite and re-ignite a main burner. Such systems shall:

Prove the presence of either the ignition source or main burner flame, or both.
Automatically ignite gas at the main burner or at the pilot burner so that the pilot can ignite the main burner, and automatically act to shut off the gas supply to the main burner or to the pilot burner and main burner, when the supervised flame or ignition source is not proved.

Ignition System Timings

Flame-Establishing Period. The period of time between initiation of gas flow and proof of the supervised flame or between the proof of supervised flame and initiation of gas flow. This may be applicable to proof of the ignition source or main burner flame, or both.
Flame Failure Re-ignition Time. The period of time between loss of the supervised ignition source or the supervised main burner flame and a re-ignition attempt. During this time period the main burner gas supply is not shut off.
Flame Failure Response Time. The period of time between loss of the supervised ignition source or the supervised main burner flame and the action to shut off the gas supply.
Ignition Activation Period. The period of time between energizing the main gas valve and deactivation of the ignition means prior to the lockout time.
Lockout Time. The period of time between initiation of gas flow and the action to shut off the gas flow in the event of failure to establish proof of the supervised ignition source or the supervised main burner flame. Reinitiating the lighting sequence requires a manual operation.
Maximum Time. The maximum allowable time for the specified function of any device.
Minimum Time. The minimum allowable time for the specified function of any device.
Purge Time. The period of time intended to allow for the dissipation of any unburned gas or residual products of combustion.
Pre-purge Time. The purge time which occurs at the beginning of a burner operating cycle prior to initiating ignition.
Post-purge Time. The purge time which occurs at the end of a burner operating cycle.
Recycle Time. The period of time between shutoff of the gas supply following loss of the supervised ignition source or the supervised main burner flame and reactivation of the ignition source.

Impurities - Undesirable foreign material(s) in a pure substance or mixture.

Indirect Internal Reforming - The reformer section is separated, but adjacent to, the fuel cell anode. This structure takes advantage of the close coupled thermal benefit from the exothermic reaction of the fuel cell to support the endothermic reforming reaction.

Inlet Test Pressures, Normal - Those pressures specified for testing purposes at which adjustment of burner ratings and primary air adjustments are made.

Input Rating - The gas-burning capacity of equipment in BTU’s per hour as specified by the manufacturer. Input ratings are based on sea level operation and need not be changed for operation up to 2,000 feet (610 m) elevation. For operation at elevations above 2,000 feet (610 m), input ratings should be reduced at the rate of four (4) percent for each 1,000 feet (305 m) above sea level.

Integration - the design and physical connection between two or more renewable energy and or conventional systems operating in harmony to reach target power production goals.

Interconnect - To link power systems in a manner that enables them to draw on one another’s reserves in time of need.

Intercooler - A heat exchanger for cooling gas between stages of a multistage compressor with a consequent savings in power.

Interlock - A control to prove the physical state of a required condition and to furnish that proof to the safety shutoff device circuit.

Internal Manifolding - A system with a self-contained reactant delivery system similar to a boxed fuel cell system that would only require connections to the reactant tanks to become operational.

Internal Reforming – See Direct Internal Reforming

Interrupter, Mechanical - A device which provides for mechanical closure of the fuel flow to the main burner by positive means such as an applied manual force through a linkage, lever handle, spring or similar mechanical means.

Ir Loss (Ohmic Polarization) - Losses created by the resistance to the flow of ions in the electrolyte and resistance to flow of electrons through the electrode and bipolar plate materials. Because both the electrolyte and fuel cell electrodes obey Ohm's law, the ohmic losses can be expressed by the equation Ohm = iR

12R Loss - Power loss due to the current (I) flow through the resistance (R) of a conductor.

Islanding - Operation of a non-utility power source with or without a portion of an electric utility system - isolated from the remainder of the utility system.

Isolated Operation - A mode of operation in which the fuel cell power plant is separated, electrically and mechanically, from all other sources of electrical energy (See Grid Isolated).

J

Joints - Points of connection: between heat transfer surfaces; between positive and negative pressure zones within components of the power plant; and between power plant components.

K

L

Labeled 1- Equipment or materials to which has been attached a label, symbol or other identifying mark of an organization acceptable to the authority having jurisdiction and concerned with product evaluation that maintains periodic inspection of production of labeled equipment or materials and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

Levelized Cost - The cost of power, expressed in either nominal or real dollars, taking into account the capital cost of the generating unit, the fuel and other O&M costs, any transmission and distribution costs applicable to the particular situation, all amortized equally over the life of the unit.

License and Permitting - Federal, State and local Utility regulations determining construction processes, safety guidelines, specific components, use, design configuration and operation of renewable energy systems. Construction Permits are filed with local municipalities who perform field inspections in each stage of construction to assure compliance with OSHA safety standards and best practices in electrical engineering design and implementation. Completed systems must be in full compliance with all regulatory requirements to operate, and allow system owners to become eligible for Federal, State and local tax incentives.

Liquid - A substance that, unlike a solid, flows readily but, unlike a gas, does not tend to expand indefinitely.

Listed 1- Equipment or materials included in a list published by a nationally recognized testing laboratory, inspection agency, or other organizations concerned with product evaluation that maintains periodic inspection of production of listed equipment or materials, whose- listing states either that the equipment or material meets nationally recognized standards or has been tested and found suitable for use in a specified application or way.

Load Duration Curve - A curve of loads, plotted in descending order of magnitude, against time intervals for a specified period.

Load-Following - A mode of operation where a power plant is generating variable power depending on the load demand.

Location, Hazardous (Classified) - Any area or space where combustible dust, ignitable fibers, or flammable, volatile liquids, gases, vapors or mixtures are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.

Low Emission Vehicle (LEV) - LEV, Low Emission Vehicle, referring to light duty passenger vehicles that meet LEV emission control standards. California’s Air Resources Board and the Federal EPA set standards for tailpipe emissions and air emissions related to the volatility of fuel used in passenger cars and light trucks. California has established several categories of vehicles, based on the maximum permitted emissions of several pollutants (See chart below). California has also established a fleet-wide emission control requirement. California LEV II Light Duty Vehicle Standards.
Mileage for Compliance Vehicle Emission Category NMOG (g/mi) Carbon Monoxide (g/mi) Oxides of Nitrogen (g/mi) 120,000 TLEV 0.156 4.2 0.6, LEV 0.090 4.2 0.07, ULEV 0.055 2.1 0.07, SULEV 0.010 1.0 0.02

Lower Explosive Limit (LEL) - The lowest concentration of a flammable gas/vapor in air in which flame is propagated.

M

Main Burner - A device or group of devices essentially forming an integral unit for the final conveyance of fuel or a mixture of fuel and air to the combustion zone, and on which combustion takes place to accomplish the function for which the equipment is designed.

Maintenance & Operations - Ongoing oversight and monitoring of completed systems to assure maximum power production and system longevity.

Manifold - The conduit of an appliance that supplies gas to the individual burner.

Materials

Combustible- As pertaining to materials adjacent to or in contact with heat-producing appliances, vent connectors, gas vents, steam and hot water pipes, and warm air ducts, shall mean materials made of or surfaced with wood, compressed paper, plant fibers, or other materials that are capable of being ignited and burned. Such materials shall be considered combustible even though flame proofed, fire-retardant treated, or plastered.
Noncombustible. For the purpose of this glossary, materials which are not capable of being ignited and burned, such as materials consisting of, or a combination of, steel, iron, brick, tile, concrete, slate, asbestos, glass and plaster.

Maximum Operating Pressure – See Operating Pressure, Maximum

Mean Time Between Failures (MTBF) - The mean exposure time between consecutive failures of a component. It can be estimated by dividing exposure time by the number of failures in that period, provided that sufficient number of failures has occurred in that period.

Mean Time Between Forced Outage (MTBFO) - A measure of the reliability of a power source, equal to its average operating between forced outages, as calculated on a statistical basis from the known failure rates of various components of the power source.

Mean Time To Repair (MTR) - The time interval (hours) that may be expected to return failed equipment to proper operation.

Measurement & Verification - Post-deployment testing to assure energy production is within the range of the original design and proposed system specification. Compliance with the original specification is a key requirement for eligibility for local Utility Rebates- which can be significant on a per watt basis.

Membrane - The separating layer in a fuel cell that acts as electrolyte (an ion-exchanger) as well as a barrier film separating the gases in the anode and cathode compartments of the fuel cell.

Membrane Electrode Assembly (MEA) - Structure consisting of a proton-exchange membrane with surfaces coated with catalyst/carbon/binder layers and sandwiched by two microporous conductive layers (which function as the gas diffusion layers and current collectors).

Mixer - The combination of mixer head, mixer throat and mixer tube.

Mixer Head. The portion of an injection (Bunsen) type burner, usually enlarged, into which primary air flows to mix with the gas stream.
Mixer Throat. The portion of the mixer which has the smallest cross-sectional area and which lies between the mixer head and the mixer tube.
Mixer Tube. The portion of the mixer that lays between the throat and the burner head.

Mixer Face - The air inlet end of the mixer head.

Mode, Disconnect - A condition of disconnection of the power plant from a utility grid following a clearing of the interrupt mode. Interrupt. A condition of momentary interruption of the current flow from the power plant to a utility grid.

Modem - A device used to connect a computer to a telephone line for transmission and reception of information.

Module - A self-contained unit that serves as a building block for the overall structure of a power source or a subsystem thereof.

Molten Carbonate Fuel Cell (MCFC).
A type of fuel cell consisting of a molten electrolyte of Li2CO3/Na2CO3 in which the species CO3 2- is transported from the cathode to the anode. Operating temperatures are typically near 650°C.
Anode reaction: H2 + CO3 2-® H2O + CO2 + 2e-
Cathode reaction: ½O2 + CO2 + 2 e- ® CO3 2-
Overall reaction: H2 +½O2 ® H2O

N

Naphtha - An artificially produced petroleum or coal tar fraction with volatility between gasoline and kerosene.

Natural Gas - A naturally occurring gaseous mixture of simple hydrocarbon components (primarily methane) used as a fuel for the production of electrical power.

Nernst Potential - An electrode potential corresponding to the reversible equilibrium between hydrogen gas at a certain pressure and the corresponding level of hydrogen ion activity.

Net Power - The difference between the power flowing from a power source and power flowing back to the source due to cumulative circuit losses and current flowing from other interconnected current sources.

Nominal Capacity - A capacity used for general rating/specification purposes. The actual capacity of a specific unit will be approximately the same as the nominal capacity but need not be exactly the same.

O

Open Circuit Voltage - The voltage at device terminals when no appreciable current is flowing. Also known as No Load Voltage.

Operation

Grid-Connected. Operation of the power plant while electrically connected to a utility grid.
Grid-Independent. Operation of the power plant while electrically isolated from a utility grid.

Operating Pressure - The variable pressure at which a system operates in response to changes in various operating conditions.

Operating Pressure, Mazimum (MOP) - The steady-state or transient gauge pressure at which a part or system operates. It shall not exceed the allowable working pressure, and it is usually kept at a suitable level below the setting of pressure-limiting/relieving devices to prevent their frequent functioning.

Orifice - The opening in an orifice cap, orifice spud or other device whereby the flow of gas is limited and through which the gas is discharged.

Orifice Cap (HOOD) - A movable fitting, having an orifice which permits adjustment of the flow of gas by changing its position with respect to a fixed needle or other device.

Orifice Spud - A removable plug or cap containing an orifice which permits adjustment of the flow of gas either by substitution of a spud with a different size orifice or by motion of a needle with respect to it.

Output Voltage - The fundamental rms. (root mean square) voltage between output terminals.

Overvoltage - A voltage above the normal rated voltage or the maximum operating voltage of a device.

Oxidant Utilization - The ratio of oxidant consumed to the oxidant supplied for consumption [(O2 in-O2 out)/O2 in].

Oxygen-To-Carbon Ratio - The ratio of the number of oxygen atoms to the number of carbon atoms in the fuel (e.g., methanol would have a ratio of 1, ethanol would have 0.5).

P

Partial Oxidation - Fuel reforming reaction where the fuel is partially oxidized to carbon monoxide and hydrogen rather than fully oxidized to carbon dioxide and water. This is accomplished by injecting air with the fuel stream prior to the reformer. The advantage of partial oxidation over steam reforming of the fuel is that it is an exothermic reaction rather than an endothermic reaction and therefore generates its own heat.

Partial Oxidation Burner - Heat source for the partial oxidation reactor.

Passive State - A state for the fuel cell internal components normally entered when the power plant is purged with steam, air or nitrogen, or per the manufacturer’s instructions when the power plant is turned off or prior to when the power plant is turned on (initialization).

Permitting & Licensing - See Agency Approvals

Phosphoric Acid Fuel Cell (PAFC) - A type of fuel cell in which the electrolyte consists of concentrated phosphoric acid (H3PO4) and protons (H+) are transported from the anode to the cathode. The operating temperature range is generally 160 – 220°C. Anode reaction: H2 ® 2H+ + 2e- Cathode reaction: ½O2 + 2H+ + 2e- ® H2O Overall reaction: H2 + ½O2 ® H2O

Pilot - A small fuel flame used to ignite the fuel at the main burner.

Continuous. A pilot that burns without turndown throughout the entire time the burner is in service, whether the main burner is firing or not.
Expanding. A continuous pilot that is automatically expanded so as to reliably ignite the main burner. This pilot may be turned down at the end of the main burner flame-establishing period.
Intermittent. A pilot that is automatically lighted each time there is a signal for initialization. It burns during the entire period that the main burner is firing.
Interrupted. A pilot that is automatically lighted each time there is a signal for initialization. The pilot fuel is cut off automatically at the end of the main burner flame-establishing period.
Proved. A pilot flame supervised by a primary safety control.

Pipeline Gas - Fuel gas delivered by pipeline and whose major component is natural gas (methane), but whose lesser components (other gaseous hydrocarbons such as propane, butane, etc. and water vapor) may vary significantly depending upon origin, time of year and other factors.

Piping - Either pipe or tubing, or both.

Pipe. Rigid conduit of iron, steel, copper, brass, aluminum, or plastic.
Tubing. Semi-rigid conduit of steel, copper, aluminum or plastic.

Piping System - All piping valves and fittings used to connect gas utilization equipment to the point of delivery.

Planar Cells – See Flat Plate Cells

Plant Footprint - An x-y illustration indicating the ground area needed for a plant (power generator) and all associated peripherals.

Plant Heat Rate - The efficiency of a power plant typically expressed in BTUs per Kilowatt-hour (BTU/kWh). 100% efficiency would equal a heat rate of 3413 BTU/kWh. The particular heat rate for a particular plant will be expressed as being based on either the Lower Heating Value (LHV) or the Higher Heating Value (HHV) of the fuel used. For natural gas, the difference is approximately 11%. Efficiencies based on the Lower Heating Value of the fuel will be approximately 11% better than those based on Higher Heating Value, for natural gas. The difference for hydrogen is approximately 20%.

Polarization Curve - Typically a plot of fuel cell voltage as a function of current density (V vs. A/cm2 or similar units). The curve is obtained under standard conditions so that fuel cell performance can be compared between different cell designs, and may be obtained by either a single cell or a stack test.

Port - Any opening in a burner head through which gas or gas-air mixture is discharged for ignition.

Power

Real. (ACTIVE USEFUL) For sinusoidal quantities in a two-wire circuit; the product of the voltage, the current, and the cosine of the phase angle between them. In a polyphase circuit; the sum of the active powers of the individual phases.
Reactive. For sinusoidal quantities in a two-wire circuit; the product of the voltage, the current, and the sine of the phase angle between them. In a polyphase circuit; the sum of the reactive powers of the phases.
Apparent. The square root of the sum of the squares of the active and the reactive powers.

Power Conditioning - The subsystem that converts the dc power from the (fuel cell) stack subsystem to dc or ac power that is compatible with system requirements.

Power Density - (kW/liter) - In the context of a single cell, the power density is often measured in terms of power/unit area of active cell, e.g., kW/sq.m; in the context of a complete cell stack, the power density could also be defined in terms of power/unit stack volume, e.g., kW/m3.

Power Factor - The ratio of the total active power in watts to the total apparent power in volt-amperes (the product of root-mean-square (rms.) voltage and rms. current). Leading. A designation of the relative instantaneous direction of the currents to the voltages (angle is 0 to -90°).Lagging. A designation of the relative instantaneous direction of the currents to the voltages (angle is 0 to +90°).

Power Plant - A packaged, self-contained, automatically operated assembly of integrated systems for generating useful electrical energy and recoverable thermal energy.

PPA Financing - A Power Purchase Agreement. PPA’s are a Renewable energy system financing model designed for large-scale projects whereby electricity is sold to the client at a fixed reduced cost per kWh over 10 to 20 years. Under a PPA, the system owner is granted a site lease and acts as a private utility, selling electricity directly to power customers, who incur no out of pocket costs. Under a PPA agreement, The system owner retains Federal, State and Local incentives and responsibility for maintenance and operations over the life of the agreement.

Preferential Oxidation - A reaction that oxidizes one chemical rather than another. In fuel cells, the reaction is used to preferentially oxidize carbon monoxide to carbon dioxide from the reformate stream after the water-gas shift reactor and before the fuel cell. Same as selective oxidation.

Preliminary Plant Design - see Energy Farm Development

Pressure - The force exerted against an opposing body or the thrust distributed over a surface, expressed in force per unit of area.

Absolute. The pressure above zero pressure, the sum of the atmospheric and gauge pressures.
Atmospheric (Standard). The pressure of the weight of air and water vapor on the surface of the earth at sea level, namely 29.92 inches (760 mm) mercury column or 14.69 pounds per square inch (101.3 kPa).
Barometric. The atmospheric pressure as determined by a barometer, usually expressed in inches (mm) of mercury.
Gauge. The pressure above atmospheric pressure.
Vacuum. Any pressure less than that exerted by the atmosphere.

Pressure Gradient Monitor - A device utilized to protect the quality of water, fail safe by design, which secures the potable water system by isolating the heat exchanger when the positive pressure gradient is less than ten (10) pounds per square inch (psi) (70 kPa) of the non-potable side.

Pressure (Pressurized) Vessel – See Vessel, Pressure

Production Analysis - See Measurement & Verification

Programmable Controller - A digitally operating electronic system designed for use in an environment, which uses a programmable memory for the internal storage of user-oriented instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic to control, through digital or analog inputs and outputs, various types of processes or machines.

Proper Ventilation – See Ventilation, Proper

Proton Exchange Membrane (PEM) - The separating layer in a PEM fuel cell that acts as an electrolyte (which is proton conducting) as well as a barrier film separating the hydrogen-rich feed in the cathode compartment of the cell from the oxygen-rich anode side.

strong>Proton Exchange Membrane Fuel Cell (PEMFC or PEFC) A type of acid based fuel cell in which the exchange of protons (H+) from the anode to the cathode is achieved by a solid, aqueous membrane impregnated with an appropriate acid. The electrolyte is a called a proton-exchange membrane (PEM). The fuel cells typically run at low temperatures (<100°C) and pressures (< 5 atm).
Anode reaction: H2 ® 2H+ + 2e-
Cathode reaction: ½O2 + 2H+ + 2e- ® H2O
Overall reaction: H2 + ½O2 ® H2O

Prototyping - Initial designs of custom parts.

Purge - To free a gas conduit of air, gas or a mixture of air and gas.

Q

R

Ra— (pronounced as Rah) The ancient Egyptian sun god. By the fifth dynasty he became a major deity in ancient Egyptian religion, identified primarily with the mid-day sun, also known as Peak Power.

Rated Power - The value stated on the generator nameplate. It is the power available at the output terminals of a component or piece of equipment that is operated in compliance with the manufacturer’s performance specifications.

Reaction Rate - A measure of the speed of a chemical reaction. The reaction rate depends on the rate constant, the number of reactants involved in the reaction and their concentration. For reactions that are otherwise slow, a catalyst is employed to increase the reaction rate.

Reformer - A vessel within which fuel and other gaseous recycle stream(s) (if present) are reacted with water vapor and heat, usually in the presence of a catalyst, to produce hydrogen rich gas for use within the fuel cell power plant.

Reformate Gas - The fluid which exits the fuel reformer and acts as feed to the fuel cell stack.

Reforming - The thermal or catalytic conversion of a hydrocarbon fuel into more volatile products with higher BTU ratings.

Regulation Capacity, Maximum - The high limit of flow below which is found acceptable regulating characteristics.

Regulator, Draft - A device which functions to maintain a desired draft in the equipment by automatically reducing the draft to the desired value.

Regulator, Gas Pressure - A device for controlling a selected outlet gas pressure.

Adjustable. Spring Type, Limited Adjustment. A regulator in which the regulating force acting upon the diaphragm is derived principally from a spring, the loading of which is adjustable over a range of not more than + 15 percent of the outlet pressure at the midpoint of the adjustment range.
Spring Type, Standard Adjustment. A regulator in which the regulating force acting upon the diaphragm is derived principally from a spring, the loading of which is adjustable. The adjustment means shall be concealed.
Convertible. A regulator for conversion between gases having different heating values whose adjustment means can be positioned from one predetermined outlet pressure setting for one gas to another predetermined outlet pressure setting for the other gas with no intermediate pressure settings and without addition, deletion or substitution of parts.
Multi-Rate. A standard adjustment regulator, the multi-rate adjustment means of which is not concealed and which provides non-field adjustable high-pressure and low-pressure settings for high-low rates.
Nonadjustable. Spring Type. A regulator in which the regulating force acting upon the diaphragm is derived principally from a spring, the loading of which is not adjustable.
Weight Type. A regulator in which the regulating force acting upon the diaphragm is derived from a weight or combination of weights.

Regulator, Pressure - A device placed in a gas line for reducing, controlling and maintaining the pressure in that portion of the piping system downstream of the device.

Reliability - The ability of an item to perform a required function under stated conditions for a stated period of time.

Reliability, Assessed - The probability that a device will function without failure over a specified time period or amount of usage.

Reliability Testing - Ongoing operational testing to verify the durability of a system or component within a system.

Reversible Fuel Cell - A type of fuel cell in which the chemical reactants undergo reversible reactions, such that the cell may be recharged with a separate power source if desired. For example, the hydrogen/oxygen fuel cell may be recharged by providing power for water electrolysis with hydrogen storage. Also called a Regenerative Fuel Cell.

Ripple Current - The undesirable AC (ripple) component of a pulsating DC current produced by a rectifier or similar power conditioning device.

Rotor Member, Non-Displaceable - A valve member which cannot be moved from its seat by a force applied to-the valve handle, or force applied by a plane surface to any exterior portion of the valve.

RPL Control Systems - Proprietary control systems technologies developed by RA POWER & LIGHT INC.

Rupture Member - A device that will automatically rupture at a predetermined pressure.

S

Safety-Control Circuit – See Circuit, Safety-Control

Scheduled Outage - An outage that results when a power plant is deliberately taken out of service at a selected time, usually for the purposes of construction, maintenance or repair.

Schedule Outage Duration - The period from the initiation of a scheduled outage until construction, preventive maintenance, or repair work is completed and the affected component is made available to perform its intended function.

Selective Oxidation – See Preferential Oxidation

Self-Contained - Having all essential working parts, except energy and control connections, so contained in a case or framework that they do not depend on equipment or fastenings outside of the machine.

Separator Plate - A solid piece of electrically conductive material (usually a metal or graphite) that is inserted between cells in a stack.

Series Connection - The connection of electrical cells in a positive to negative pattern such that individual cell voltages are additive.

Service Factor - A multiplier that, when applied to the rated power, indicates a permissible power loading that may be carried under the conditions specified for service factor.

Shield, Radiation - A separate panel or panels interposed between surfaces and jackets to reduce heat losses through radiation.

Shift Conversion - The reaction of CO with water to generate carbon dioxide and hydrogen. This process is performed immediately after the reformer and before the preferential oxidizer to reduce CO from approximately 10% down to 0.5% to 0.1% usually through a water gas shift reaction.

Shut-Down - When a system is not supplying or receiving power (the process of decreasing the power to zero).

Shutdown, Safety - The action of shutting off all fuel and ignition energy to the fuel utilization equipment by means of a safety control or controls such that restart cannot be accomplished without manual reset.

Shutoff Device, Safety - A device that will shut off the fuel supply to the controlled burner in the event the source of ignition fails. This device may interrupt the flow of fuel to the main burner only, or to the pilot and main burner under its supervision.

Single Cell Test - A test of the fuel cell performance based on one unit cell. The test is typically a laboratory scale test in which several variables can be adjusted in order to obtain data over a wide range of conditions, such as temperature, current density, fuel and oxidant flow rates, etc. The outcome of a single cell test may be a polarization curve, a voltage stability plot, or other data related to fuel cell performance.

Site Development - Preparation and design for underground wiring, construction and Grid integration.

Soil Analysis - Tests determining the geological structure of the site, including load bearing attributes and potential vulnerability to seismic activity. See Energy Farm Development.

Solid Oxide Fuel Cell (SOFC) - A type of fuel cell in which the electrolyte is a solid, nonporous metal oxide, typically ZrO2 doped with Y2O3, and O2- is transported from the cathode to the anode. Any carbon monoxide (CO) in the reformate gas is oxidized to carbon dioxide (CO2) at the anode. Temperatures of operation are typically 800 – 1000°C.
Anode reactions: H2 (g) + O2- ® H2O (g) + 2e CO (g) + O2- ® CO2 (g) + 2e-
Cathode reaction: O2 + 4e- ® 2O2-
Overall reaction: O2 + H2 + CO ® H2O + CO2

Sound Level - The sound pressure level (in decibels) at a point in a sound field, averaged over the audible frequency range and over a time interval, with a frequency weighting and time interval specified by the American National Standard Association.

Specific Gravity - The ratio of the weight or mass of a given volume of a substance to that of an equal volume of another substance (air for gases, water for liquids and solids) used as a standard, both measured under the same conditions.

Specific Power (kW/kg) - A measure of the energy generating or storage potential of a system per unit of weight.

Specification Development - The proposed system design and bill of materials based upon energy requirements and site attributes.

Stack End Frame - A frame used to compress the individual cells together to maintain electrical conductivity. Also may be known as an end plate or compression end plate.

Stack Life - The cumulative period of time that a fuel cell stack may operate before its output deteriorates below a useful minimum value.

Stack Test - Experiment where an electrical load is applied to a stack of fuel cells to determine its ability to perform. Normally, the output seeks two pieces of information. First is a current output at a specific cell voltage point. Second is a continuous voltage vs. current curve (polarization curve.)

Stacking - The process of placing individual fuel cells adjacent to one another to form a fuel cell stack. Normally, the stack is connected in a series.

Standard Atmosphere - A standard unit of atmospheric pressure, defined as that pressure exerted by a 760-millimeter column of mercury at standard gravity (980.665 centimeters per second per second) at temperature 0 degrees C.

Standard Conditions - The test or operating conditions that have been predetermined to be the basis of the test in order to have reproducible, comparable sets of test data. Typical conditions that are standardized are fuel and oxidant flow rates and ratios, temperature, pressure, electrode area, catalyst loading, etc.

Standby - A power circuit equipment, device, or component available to be connected into the circuit to perform a function when the preferred component has failed or is inoperative.

Standby Power - An independent reserve source of electric energy that upon failure or outage of the normal source, allows the user’s facilities to continue in satisfactory operation.

Stationary Power Plants - Source of electricity that remains in one location

Steam Bottoming Cycle - A heat recovery system that uses waste heat from a power system to boil water forming steam that would typically be used to run a steam turbine to generate additional power from the heat that would otherwise be wasted. This increases the efficiency of the basic device.

Steam Reforming - The process for reacting a hydrocarbon fuel, such as natural gas, in the presence of steam to form hydrogen as a product. This is the commonly preferred method of bulk hydrogen generation.

Steam-To-Carbon Ratio - The number of moles of water per mole of carbon in either the reformate or the fuel streams. This term is used when steam is injected into the reformate stream for the water-gas shift reaction or into the fuel for steam reforming.

Stoichiometric Ratio - The perfect oxidizer to fuel ratio (O/F) in a reaction such that all of the oxidizer exactly reacts with all of the fuel.

Stop - A fixed point on a control, such as a temperature limit control, which prevents the adjustment of the control beyond the stop point.

Stop, Fixed - A stop that cannot be changed without the use of special tools.

Storage Systems - Systems which store energy for use during off-peak hours- See Batteries

Strength, Ultimate - The stress level that a pressure-bearing part can tolerate without rupture, fracture, deformation or other physical damage.

Structural Design - Ra Power & Light Architectural and engineering designs to assure proper weight distribution of the proposed system for the structures it will be installed on.

Sub Station Development – See Energy Farm Development

Substack - Typically a group of stacked fuel cells that makes up the base repetitive unit number of cells per full stack. Sub stacks may form an intermediate step in manufacturing and may be used to test new stack concepts prior to scale-up to full size stacks.

Substances - As applied to this glossary, substances include, but are not limited to, solutions, lubricants, adhesives, sealants, etc.

Synchronization - Operation at which a power plant is electrically connected and controlled to operate at the same frequency & voltages, and where the phase-angle displacements between voltages in them are constants or vary about steady and stable average values.

System Modeling - Energy production output calculated based upon possible configuration and component variables provided in specifications for the proposed system.

T

Temperature - A measure of heat intensity.

Absolute. The temperature above absolute zero, or temperature plus 273°C or 459°F.
Ambient. The temperature of the surrounding medium, usually used to refer to the temperature of the air in which a structure is situated or a device operates.

Thermal Efficiency - Efficiency with which a power source transforms the potential heat of its fuel into work or output, expressed as the ratio of the useful work done by the power source in a given time interval to the total heat energy contained in the fuel burned during the same time interval, both work and heat being expressed in the same units.

Thermostat - An automatic control device actuated by temperature and designed to be responsive to temperature.

Thermal Management - The directing of heat entering or exiting a system.

Three-Phase Three Wire System - A system of alternating-current supply comprising three conductors between successive pairs of which are maintained alternating differences of potential successively displaced in phase by one-third of a period.

Three-Phase Four Wire System - A system of alternating-current supply comprising four conductors, three of which are connected as in three-phase three-wire system, the forth being connected to the neutral point of the supply, which may be grounded.

Timer, Watchdog - A device that detects controller malfunction and initiates independent action to safely deactivate the equipment operated by the failed controller. The device accomplishes failure detection, by monitoring a periodic update signal from the controller, and activation, if this periodic signal does not occur within a specified time period.

Total Harmonic Distortion (THD) - The ratio of the root-mean-square (RMS) value of the sum of the squared individual harmonic amplitudes to the rms value of the fundamental frequency of a complete waveform.

Transportation - Term applied to the market sector that includes light duty vehicles, busses, heavy-duty vehicles, and off-road vehicles.

Tubular Cells - Fuel Cells that are formed in cylindrical fashion and allow fuel and oxidant to flow on the inner or outer surfaces of the pipe.

Turbocharger - A device used for increasing the pressure and density of a fluid entering a fuel cell power plant using a compressor driven by a turbine that extracts energy from the exhaust gas.

Turbocompressor - Machine for compressing air or other fluid (reactant if supplied to a fuel cell system) in order to increase the reactant pressure and concentration.

Turbo-Expander - Machine for expanding air or other fluid (reactant if supplied to a fuel cell system) in order to decrease the fluid pressure and concentration. The unit is normally used in conjunction with a compressor to recover unused energy from hot, pressurized gasses, thereby reducing the net amount of energy required to power the compressor.

U

Ultra-Low Emission Vehicle (ULEV) - See LEV

V

Valve - A device used in piping to control the fuel supply to any section of a system of piping or to fuel utilization equipment.

Automatic. A device consisting essentially of a valve and operator that controls the fuel supply to the burner during normal operation of the equipment. The operator may be actuated by application of fuel pressure on a flexible diaphragm, by electrical means, by mechanical means or by other means. Diaphragm Type. A device consisting essentially of an automatic valve actuated by means of the application of fuel pressure upon a flexible diaphragm.
Electric Type. A device actuated by electrical energy for controlling the fuel supply. These consist of the following: Modulating. A valve designed so the valve opening is controlled within narrow limits throughout the entire range from the "full open to the "closed" position. Motor. An electric control valve that is automatically closed by a spring or other mechanical means in the event the electric circuit is broken.
Solenoid. A valve that is opened or closed by the action of an electrically excited coiled wire magnet upon a bar of steel attached to the valve disc.
Step (Manual). A valve having a rotating plug with, generally, three positions and different rates of fuel flow for each, the plug being actuated by a solenoid or motor-driven rack and pinion and a cam arrangement which, together with a combination push-button switch, determines the position assumed by the plug.
Burner. A manually or mechanically operated valve which permits control of the flow of fuel.
Combustion (input) Control. An automatic control valve for regulating fuel input.
Latching Type. A manual gas valve which requires at least two separate actions or movements to turn on the valve, as for example, pushing in on the valve handle to unlatch the valve before the valve handle can be rotated to turn on the fuel.
Lubricated Plug. A valve of the plug-and-barrel type that has bearing surfaces designed to be re-lubricated without disassembly of the valve.
Main Burner, Individual. A valve that controls the fuel supply to an individual main burner. Semi-Automatic. A valve that is opened manually and closed automatically, or vice versa.
Shutoff, Manual. A manually operated valve in a fuel line for the purpose of completely turning on or shutting off the fuel supply to fuel utilization equipment.
Shutoff, Manual Main. A manually operated valve in the fuel line for the purpose of completely turning on or shutting off the fuel supply to fuel utilization equipment, except to a pilot provided with independent shutoff valves.
Shutoff, Safety. A valve that is automatically closed by the safety control system or by an emergency device. Such valve may be of the automatic or manually opened type.

Valve, Control - A valve used to control the flow of any medium.

Valve, Operating - An operating valve is an automatic valve controlled by an operating control.

Valve, Relief - A safety valve designed to forestall the development of a dangerous condition by relieving either pressure, temperature or vacuum in a fluid based system.

Pressure. A valve which automatically opens and closes a relief vent, depending on whether the pressure is above or below a predetermined value.
Temperature. A valve which automatically opens and closes a relief vent, depending on whether the temperature is above or below a predetermined value.
Vacuum. A valve which automatically opens and closes a vent for relieving a vacuum within the a system, depending on whether the vacuum is above or below a predetermined value.

VAR - A unit of reactive power in a circuit carrying a sinusoidal current. A VAR equals the amount of reactive power in the circuit when the product of the root-mean-square value of the voltage (volts) by the root-mean value of the current (amps) and the sine of the phase angle between the voltage and the current, equals 1.

Vent - A passageway or conduit for conveying products of combustion from fuel utilization equipment, or their vent connectors, to the outside atmosphere.

Vent Connector - That portion of the venting system that connects the flue outlet of fuel utilization equipment to the gas vent or single-wall metal pipe.

Vent Gases - Products of combustion from fuel utilization equipment plus excess air, plus dilution air in the venting system above the draft regulator or similar device.

Vent Limiter - A means that limits the flow of air from the atmospheric diaphragm chamber of a gas pressure regulator to the atmosphere. This may be either a limiting orifice or a limiting device.

Vent Terminal (Vent Cap) - The opening at the end of the vent pipe that directs the flue products into the outside atmosphere.

Ventilation - The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from any space.

Ventilation, Proper - In general, the dilution of a flammable gas/vapor with air to a point safely below its lower explosive limit (LEL). As applied to this standard, a sufficient or adequate supply of fresh air and proper exhaust to outdoors or to a safe location with a sufficiently-vigorous and properly distributed air circulation to ensure that the flammable gas/vapor concentration in all parts of the enclosure will be below 25 percent of the LEL at all times.

Venting System - The gas vent or single-wall metal pipe, and vent connector if used, assembled to form a continuous open passageway from the flue collar of gas utilization equipment to the outside atmosphere for the purpose of removing vent gases.

Vessel, Pressure - Containers for the containment of pressure either internal or external. This pressure may be obtained from an external source, or by the application of heat from a direct or indirect source, or by any combination thereof. Exceptions: vessels having an internal or external operating pressure not exceeding 15 psi (103.4 kPa) with no limitation on size; vessels having an inside diameter, width, height or cross section diagonal not exceeding six (6) inches (152 mm) with no limitation on length of vessel or pressure.

Fired. A vessel containing a fluid under pressure exposed to heat from the combustion of fuel gas, reformer gas of combustible gas derived from fuel gas or from electricity.
Unfired. A vessel designed to withstand internal pressure, neither subjected to heat from products of combustion nor an integral part of a fired pressure vessel system.

Vessel, Unpressurized - A vessel for containment of fluids not subject to the definition of Pressure Vessel.

Voltage, Harmonic - A voltage whose frequency is a multiple of the fundamental frequency.

W

Working Pressure, Allowable- The maximum gauge pressure at which a part or system may be operated in accordance with the provisions of this standard. It is the pressure used in determining the setting of pressure limiting/ relieving devices installed to protect the part or system from accidental over pressuring.

X

Y

Z

Zero Electric Vehicle (ZEV). Zero Emission Vehicle, a vehicle that produces no air emissions from its fueling or operation. California regulations require in 2003, 10% of the vehicles sold in California by major auto makers be ZEV or ZEV equivalent. California has established a comprehensive program for determining this equivalency. See also LEV. Endnotes: 1 Denotes definitions derived from ANSI Z21. 83/ (GA12.10) and, while relevant with that standard, do not necessarily apply to a fuel cell power plant.

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