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 Mobile ViewHEATING SYSTEMS AFUE DEFINITION, RATINGS AGE of AIR CONDITIONERS & HEAT PUMPS AGE of HEATERS, BOILERS, FURNACES AIR CONDITIONING & HEAT PUMP SYSTEMS AIR FILTERS for HVAC SYSTEMS AIR HANDLER / BLOWER UNITS AIRBOUND HEAT SYSTEM REPAIRS ANODES & DIP TUBES on WATER HEATERS ANTI SCALD VALVES ANIMAL ALLERGENS / PET DANDER ANIMAL ENTRY POINTS in buildings ANIMAL ODORS IN buildings APPLIANCE EFFICIENCY RATINGS ASBESTOS IDENTIFICATION IN buildings BACKDRAFTING HEATING EQUIPMENT BACKFLOW PREVENTERS BACKDRAFTING HEATING EQUIPMENT BACKUP HEAT for HEAT PUMPS BAROMETRIC DAMPERS BASEBOARD HEAT BIOGAS PRODUCTION & USE BLEVE EXPLOSIONS BLOWER DOORS & AIR INFILTRATION BLOWER FAN CONTINUOUS OPERATION BLOWER FAN OPERATION & TESTING BLUE vs YELLOW COMBUSTION FLAMES BLUERAY Recall BOILERS, HEATING BACKDRAFTING HEATING EQUIPMENT BOILER COMPONENTS & PARTS BOILER CONTROLS & SWITCHES BOILER LEAKS CORROSION STAINS BOILER LEAKS, HOW TO LOCATE BOILER NOISE SMOKE ODORS BOILER OPERATING PROBLEMS BOILER OPERATION DETAILS BOILER PRESSURE & TEMPERATURE SETTINGS BOOKSTORE - InspectAPedia BUILDING SAFETY HAZARDS GUIDE CAPACITORS for HARD STARTING MOTORS CARBON DIOXIDE - CO2 CARBON MONOXIDE - CO CARBON MONOXIDE WARNING CHIMNEY INSPECTION DIAGNOSIS REPAIR CHIMNEYS & Flues - Asbestos Transite Pipe CHINESE DRYWALL HAZARDS CIRCULATOR PUMPS & RELAYS COOL OFF HEAT, Thermostat Switch COMBUSTION AIR COMBUSTION PRODUCTS & IAQ COMPLETE COMBUSTION, Stoichiometric CONDENSING BOILERS/FURNACES CONDENSING BOILERS/FURNACES DAMAGE CONVECTOR HEATERS - HYDRONIC COILS DEFINITION of Heating & Cooling Terms DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP DIAGNOSE & FIX HEATING PROBLEMS-BOILER DIAGNOSE & FIX HEATING PROBLEMS-FURNACE DRAFT HOODS - gas fired DRAFT MEASUREMENT, CHIMNEYS & FLUES DRAFT REGULATORS, DAMPERS, BOOSTERS DRAFT MEASUREMENT, CHIMNEYS & FLUES DRAFT REGULATORS, DAMPERS, BOOSTERS DUCT INSULATION, Asbestos Paper DUCT SYSTEM & DUCT DEFECTS DUCTS, Asbestos Transite Pipe DUST CONTAMINATION FROM HVAC? ELECTRIC HEAT ELECTRIC MOTOR DIAGNOSTIC GUIDE ELECTRIC MOTOR OVERLOAD RESET SWITCH ELECTRICAL POWER SWITCH FOR HEAT ENERGY SAVINGS in buildings EVAPORATIVE COOLING SYSTEMS FAN, AIR HANDLER BLOWER UNIT FAN AUTO ON Thermostat Switch FAN, COMPRESSOR/CONDENSER UNIT FAN CONVECTOR HEATERS - HYDRONIC COILS FAN LIMIT SWITCH FAN NOISES FILTERS, AIR for HVAC SYSTEMS FILTERS, OIL on HEATING EQUIPMENT FIRE SAFETY CONTROLS FIREPLACES & HEARTHS FLAME COLOR, BLUE vs YELLOW COMBUSTION FLOODED HEATING EQUIPMENT REPAIR FLOODED WATER HEATER REPAIR FLUE SIZE SPECIFICATIONS FLUE VENT CONNECTORS FREEZE-PROOF A BUILDING FUEL OIL TYPES & CHARACTERISTICS FUEL UNIT, HEAING OIL PUMPS FURNACES, HEATING FURNACE CONTROLS & SWITCHES FURNACE HEAT EXCHANGER LEAKS FURNACE OPERATION DETAILS FURNACE OPERATING TEMPERATURES GALVANIC SCALE & METAL CORROSION GAS BURNER Flame & Noise Defects GAS FIRED WATER HEATERS GAS PIPING, VALVES, CONTROLS GAUGES ON HEATING EQUIPMENT HEAT LOSS in buildings HEAT LOSS DETECTION TOOLS HEAT LOSS INDICATORS HEAT LOSS PREVENTION PRIORITIES HEAT LOSS R U & K VALUE CALCULATION HEAT PUMPS, DiAGNOSIS, REPAIR HEAT TAPES, Heat, Insulation prevent Freeze-Up HEATING COST FUEL & BTU Cost Table HEATING COST SAVINGS METHODS HEATING LOSS DIAGNOSIS-BOILERS HEATING LOSS DIAGNOSIS-FURNACES HEATING OIL CLOUD WAX GEL POINT HEATING OIL EXPOSURE HAZARDS, LIMITS HEATING OIL - OLD, USEABLE? HEATING OIL PIPING TROUBLES HEATING OIL SHELF LIFE HEATING OIL SLUDGE HEATING OIL USAGE RATE HEATING SMALL LOADS HEATING SYSTEM NOISES HEATING SYSTEM SERVICE & MAINTENANCE HEATING SYSTEM INSPECT DIAGNOSE REPAIR HEATING INSPECTION CONCEPTS HEATING INSPECTION PROCEDURE HEATING SYSTEM INSPECTION DETAILS HOT WATER HEATERS HOT WATER IMPROVEMENT INSULATION INSPECTION & IMPROVEMENT LP & Natural Gas Safety Hazards MANUALS & PARTS GUIDES - HVAC MIXING / ANTI-SCALD VALVES MOTOR OVERLOAD RESET SWITCH Natural Gas Combustion Products NO HEAT - BOILER / FURNACE DIAGNOSIS NOISE / SOUND DIAGNOSIS & CURE NOISE AIR CONDITIONER / HEAT PUMP NOISE, DUCT VIBRATION DAMPENERS NOISE CONTROL for HEATING SYSTEMS NOISE CONTROL for PLUMBING NOISES COMING FROM WATER HEATER ODORS & SMELLS DIAGNOSIS & CURE ODORS FROM HEATING SYSTEMS OIL BURNERS OIL BURNER INSPECTION GUIDE OIL BURNER NOISE SMOKE ODORS OIL BURNER NOZZLE & ELECTRODES OIL BURNERS, RETENTION HEAD OIL BURNER SOOT & PUFFBACKS OIL FILTERS on HEATING EQUIPMENT OIL FILTER MISSING OIL FUEL TYPES & CHARACTERISTICS OIL & GAS PIPING GAS PIPING, VALVES, CONTROLS OIL TANK PIPING & PIPING DEFECTS OIL LINE CLOGGING FIX OIL LINE SAFETY VALVES OIL ODORS, LEAKY OIL TANK PIPING OIL PUMP FUEL UNIT OIL SPILL CLEANUP / PREVENTION OIL TANKS OIL TANKS, BURIED OIL TANK GAUGES OIL TANK INSPECTION REPORTS OIL TANK LEAKS & SMELLS OIL TANK PIPING & PIPING DEFECTS OIL TANK PRESSURE OIL TANK REGULATIONS OIL TANK REMOVAL COs OIL TANK REMOVAL FINANCIAL AID OIL TANK SAFETY OIL TANK SLUDGE OIL TANK TESTING OIL TANK TESTING COs OIL TANK WATER CONTAMINATION OIL TANK WATER REMOVAL PLASTIC HEATER VENT PULSE COMBUSTION HEATERS PASCAL CALCULATIONS RADIANT BARRIERS RADIANT HEAT RADIANT HEAT Floor Mistakes to Avoid RADIANT HEAT TEMPERATURES RADIANT SLAB FLOORING CHOICES RADIANT SLAB TUBING & FLUID CHOICES RADIATORS RELIEF VALVES - TP Valves on Boilers RELIEF VALVES - STEAM TP VALVES RELIEF VALVES - Water Heaters RELIEF VALVES - Water Tanks Reset Switch - Heater Primary Control Reset Switch - Electric Motors Reset Switch - Stack Relays SAFETY HAZARDS & INSPECTIONS SAFETY HAZARDS GUIDE SAFETY, HEATING INSPECTION SAFETY,HOME HEATING TIPS Safety Recalls, Chimneys, Vents, Heaters BLUE vs YELLOW COMBUSTION FLAMES BLUERAY Recall CHIMNEYS & Flues - Asbestos Transite Goodman HTPV RECALL Heat Recovery Ventilator RECALL Lennox Furnace Manuals Lennox SAFETY WARNING PLASTIC Plexvent / Ultravent RECALL Weil McLain RECALL SOLAR ENERGY SYSTEMS SOOT on OIL FIRED HEATING EQUIPMENT SPILL SWITCHES - Flue Gas Detection SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS STACK RELAY SWITCHES STAIN DIAGNOSIS on BUILDING INTERIORS STEAM HEATING SYSTEMS TANKLESS COILS THERMAL EXPANSION of MATERIALS THERMAL MASS in buildings THERMAL TRACKING & HEAT LOSS THERMOSTATS, HEATING / COOLING Transite Pipe Chimneys & Flues VIDEO GUIDES: Heating System Videos VIDEO GUIDES - InspectAPedia.com WATER HEATERS WATER HEATER SAFETY WATER HEATERS for HOME HEATING USE? WATER HEATER NOISES WATER HEATER SCALE - De-Liming Procedure WATER HEATER SCALE PREVENTION WINTERIZE A BUILDING Wood Burning Heaters Fireplaces Stoves Woodstove Safety ZONE VALVES More Information |
Here, courtesy of aerospace engineer Herman Vogel, we discuss the relation of blue flame and efficient oil or gas combustion in engines or in heating equipment. Mr. Vogel explains how the blue flame theory found its way into the later unsafe BlueRay Heating equipment line (see BLUERAY Recall). Our page top photo shows a blue-colored flame photographed on a heating boiler burner using natural gas fuel. Also see COMPLETE COMBUSTION, Stoichiometric - discussing the complete combustion of fossil fuels and the details as well as the significance (to non-engineers) of Stoichiometric Combustion. Readers should also see CARBON MONOXIDE WARNING. This website answers most questions about central heating and water heating systems to aid in troubleshooting, inspection, diagnosis, and repairs. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. Theory of Blueray and What it Really Means to be Combustion EfficientHerman Vogel, Aerospace Engineer I used to design combustors for Pratt&Whitney Aircraft (P&WA). Later on it was top-secret government work for the InfraRed Countermeasure world where we created combustor-driven systems that would confuse heat seeking missiles from acquiring hot jet-engine targets. This was back in the late 60's early 70's, a few years before the concept of BlueRay came out! Why Blue Flames Indicate Superior Combustion Efficiency
Our sketch (at left) shows how an oil burner gun atomizes and sprays heating oil into the combustion chamber - Audel Oil Burner Guide. Measure a blue flame temperature and you get around 3,000F. Measure a yellow flame temperature and you get about 1,400 to 2,000F at best (depending on how well the combustor atomizes liquid fuel and mixes it with oxygen). Just from temperature alone, one recognizes the superior aspects of blue flames. Blue flames run closer to stoichiometric conditions of combustion, that is they burn as if using a pure gaseous fuel as opposed to liquid. (See COMPLETE COMBUSTION, Stoichiometric for details). Gases basically burn 100% efficient or stoichiometrically. Jet engine manufacturers like P&WA, GE, and RR all take great pains in trying to design their combustors to first convert liquid fuel into fine atomized liquid droplets, then convert these droplets into pure vapor before they are allowed to mix with pressurized air (only oxygen part of air) for near complete combustion. This yields about 95+% efficient combustion today. What happens here is that the fuel surface area, available for mixing with oxygen and burning more effectively, increases by factors of 1000 over that available with only atomized droplets of fuel. Blue Flame Efficiency and the History of BlueRay Heating Boilers in the 1970'sThe BlueRay folks got wind of these concepts back in the early 70's (perhaps even hiring some of the jet engine engineers?) to create their widely touted and highly efficient combustion process technology. It's a shame that their product couldn't survive the rigors required by both the residential and commercial heating furnace customers. Unfortunately, it took a lot more tender loving care to keep the BlueRay flame "blue" than your typical yellow flamed combustors. And as is pointed out at BLUERAY Recall, poorly tuned BlueRay's had a tendency to burn sooty and rich, emitting Carbon, CO and NOx in their exhaust. Two Measurements of Combustion EfficiencyIf I burn a pound of fuel, and get 3,000F flame temperature out of it as opposed to 2,000F, I'm getting more heat (efficiency) out of the same amount of fuel. In fact, true thermodynamic combustion efficiency of any combustor (jet engine, car, furnaces, etc.) can be measured in two ways, with both relying on the stoichiometric chemical reaction formula for complete combustion;
What is the True Efficiency Indicated by Yellow Flames? - How Oil Competes with Gas as a Heating FuelNow, if a yellow furnace system (with heat gun, combustion-chamber and exhaust-pipe) can at best only deliver about 51% efficient running, according to absolute thermodynamic principles, how do furnace companies and maintenance technicians claim efficiencies of 85% or even 90% or better? They have collaborated, industry wide, to re-define oil-burning efficiency according to more favorable terms that can compete with the gas industry. While there is nothing wrong with that, the basic problem lies in allowing them to conveniently forget that they should not compare their home-grown heating oil efficiency to "real" and absolute efficiency values as with burning methane or natural gas in furnaces or even JP-fuels in jet engines. A Comparison of Oil Fuel vs Gas Fuel Efficiency in Heating EquipmentConsumers don't know what they are really getting when the oil industry compare apples to pears. When a fuel-oil furnace that is burning No#2 home heating oil is said to burn 100% efficient (based on non-stoichiometric reactions, defined by the furnace industry as standard, and using CO and CO2 exhaust product ratios to "relatively" redefine efficiency), their real furnace flame temperature would actually measure only about 2,000F at best. Obviously, this is nowhere near 100% operation based on the above calculated theoretical analysis. Now as their hypothetical flame decreases in temperature, the CO and CO2 fractions will change, and, depending upon the ratio of these changes, a new burner efficiency of under 100% gets quoted. Again, these are not absolute thermodynamic values, rather they are relative burning efficiencies based on a reference flame temperature of 2,000F which was arbitrarily chosen to represent 100% combustion efficiency. One may as well state that if your furnace has been tuned and reads 85% efficiency, as arbitrarily based on its emissions of CO and CO2 , it is really burning at [51% x 0.85 or] 43% efficiency in terms of "absolute thermodynamic efficiency". Compare this to any gas furnace burning 100% in "absolute thermodynamic efficiency" and you are effectively throwing out almost half of your heating oil value. How Oil Fuel is Competitive with Gas Fuel for Heating buildingsWhile this is shocking and true, remember that oil heat has as yet certain redeeming qualities. It is still cheap enough to allow this disparity to happen and yet be competitive in heating your home because of its 40% greater heating value and 7% greater flame temperature (IHV=18,950 BTU/Lbm, IFT=3,850F) compared to natural gas (IHV=13,660 BTU/Lbm, IFT=3562F). (See Natural Gas Combustion Products) While BlueRay technology tried to take advantage of this disparity in efficiency, sadly they lost out to the need for frequent maintenance visits and to keep the unforgiving technology properly tuned or produce killing CO gases. Bad Design and BlueRay - Design Products For What People are Likely to Actually Do
For example, when adjusting the air-fuel mix by changing the air shutter opening on the oil burner, the direction of change, from more lean to more rich versus adjusting from the more rich to the more lean position could be enough to leave the oil burner adjusted to an unsafe position that would produce dangerous carbon monoxide. Here is what the company's service bulletin said:
The subtlety of having to care about the direction from which one makes an adjustment to a common oil burner device, when either way the adjustment appeared to end at the same setting was perhaps too much to ask of traditional oil heat service technicians who were accustomed to more than sixty years of oil burners hat were wonderfully tolerant of rough handling. Across a very wide range of discussions of construction problems and failures, we often return to this point. Good product design should provide for what people are likely to do (in installation, service, maintenance, use) rather than what the designer thinks they should do. Also see Readers should also see these non-technical oil burner articles: and see these safety articles Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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