• Tag Archives Coal
  • COAL, THAT POLITICALLY INCORRECT, OTHER HEATING FUEL

    Coal is our most plentiful yet most maligned source of energy. Generating the majority of our electrical power and fueling heavy industry, it has projected the United States from an agricultural to the predominant industrial society in less than a century. But with the EPA’s focus and regulatory squeeze, it has become the convenient “dog to kick”.

    However, the dog and the coal industry are not beaten yet. Witness the shift to exporting our coal to Eastern Europe, the Far East and resurgence of coal “parlor heaters’ supported by bagged fuel. This is not all, however. Economics Rule!

    We have recently through a series of coincidences come to acquaint a fellow tradesman whose specialty is automatic coal-fired hydronic (FHW) systems. His niche is larger, energy-intensive applications such as greenhouses, up-scale housing and “expansion mansions”. (The latter is a regional term denoting seasonal homes that are inordinately expanded and upgraded.) Greenhouses are typically gas, oil or wood heated at significant expense in an effort to survive economically. Upscale housing and “expansion” owners are motivated by pure economics in substituting or augmenting their heating system requirements. Again the latter is where we cross paths.

    Our market effort is providing a Premium, Optimized, and Packaged American Gas or Oil Hydronic Boiler System, ready to “plug & play”. We can also supply our systems pre-piped to interface with a coal/wood boiler as a fully integrated system. There is therefore in our view a very complimentary pairing of coal and wood boilers with gas or oil powered hydronic distribution systems.

    As a solid fuel system a coal fire must be maintained continuously while being modulated (adjusted) to suit heating demands. You don’t just turn a coal fire on and off with a switch, as with gas or oil powered burners. Thus you must utilize or dissipate the minimum fire energy, or let it extinguish. This relegates automatic stoker-fed coal systems to being effectively a heating-season-only appliance.

    The complimentary match is an integrated gas or oil burner boiler to provide the minimal heat and domestic hot water (DHW) requirements off the coal cycle. Thus is our affiliation with our coal systems guy. Whether it’s integrating an existing powered system with coal as previous or providing an overall solution, coal (or wood) systems can be very complimentary indeed.

    The surprise has been the economics of coal as a residential heating fuel, if you work around its physical attributes and distribution challenges. Idealizing its use can make coal more economical than even a sophisticated natural gas system. We have ‘run the numbers’ to our amazement! Let us elaborate.

    First, coal pricing is not necessarily a distribution determined commodity. You would not recognize this as a parlor stove, bagged coal user, but as a central heating system fuel you enter the bulk product market. Now you have options, similar in some regards to the cordwood vs. wood pellets scenario, with one notable exception ….. energy density.

    Coal has a moderately high energy density in comparison to wood for instance, being a necessarily granulated product for automatic stoker-fed coal FHW boiler systems. You can easily handle and pack a lot of it into a storage space. So the key is to ultimately source and deliver the product from its source location in bulk.

    There are two (2) means available, truck or train, or a combination of both. Your strategy is therefore predicated by your point-of-use transport and/or transfer site availabilities. Ultimately your option(s) will be driven by the nearest raw material source. In our case (North Central New England) we have no railhead or ‘coal shed’ facilities (truck under coal hopper car drop site). So we source typically from N.E. Pennsylvania. The ‘coal shed’ is likely the most efficient transit-transfer method, dictated by capacities:

    1. A coal train hopper car has a capacity of well over 100 tons.
    2. A tractor-trailer can legally haul about 22 tons maximum.
    3. A dump truck (for local drop) will vary depending upon its GVW.

    Now you must do the math, based upon your specific annual requirements, individual handling and available storage. Obviously you must work upwards from your system active hopper charge size, considering your refill frequency, etc. to optimize your pattern.

    Your opportunity is to move your fuel from the mine(?) yard at about $100+/- a ton to yours with minimum transit & handling cost. The local scenario is employing an independent Pennsylvania Semi-Trucker who delivers his 22-ton load here, and then back-hauls a bulk load home. This can be wood by-products, aggregates, scrap metal or whatever from this area. Obviously planning and scheduling are in order, and the resultant is a $250 per ton or less delivered cost.

    At $250 a ton or less coal trumps even natural gas (available or not) heating costs utilizing a 95% efficient Condensing Gas Boiler! This is in contrast to a $350+/- per ton cost of buying bagged coal from the local stove shop as a convenience (and handling it).

    The advantage as we see it of an integrated coal-oil or coal-LP (Propane) system is having your energy storage all on-site, and with a generator backup being totally unaffected by both electric outages and heating energy cost fluctuations.

    We must necessarily defer to the coal guy for technical and operational details. Our interest is solely to inform the consumer of all his options while noting our potential technical contribution to heating system integration and performance.

    Well, almost the only reason. Permit me a reflection.

    As a child at the end of WWII I vividly recollect our home being steam-heated with 11 cords of wood annually, and being cold in the process. Not to mention taking away cord wood from a whistling, open saw inches away from your hands and stacking it, seemingly forever. My Dad and a one-armed Uncle operated his saw, the same one that had taken his arm several years earlier. My Dad had had enough.

    We converted to an automatic coal stoker system with a large bin. Recall several nights being shaken out of sleep in a cold house to help my father fix the boiler. My task was to hurriedly dig to the bottom of the coal bin with my hands and remove a piece of chunk coal mixed into the bin that had stuck and sheared the auger feed pin. Meanwhile my Dad built a new fire and replaced the shear pin after my dislodging the chunk. Washing off all that coal dust with Lifebuoy Soap in cold water was the climax, and then hopping back into bed in a hurry.

    Otherwise we always had a nice warm house with radiators hissing that we could back up against, warm ourselves and dry our clothes. Loved that old coal stoker!

    Old, pleasant memories become more vivid as we age, don’t they?


  • INTERIOR VS. OUTDOOR WOOD BOILER SYSTEMS — SOME OBSERVATIONS

    Having now maintained our own Interior, Integrated Wood & Oil Heating System since 1975 and more recently integrating Outdoor Wood Boilers to our Weil-McLain FHW Heating Systems,  we are motivated to pass on some of our observations.

    (Note hyperlinks within the document.)

    Disclaimer: We are exclusive Weil-McLain Heating Designers & Installers here in NH only (thus far). We do not nor have not specified, sold or initially installed any interior or outdoor “Solid Fuel” (Wood, Pellets, Coal, etc.) Boilers. Our participation has been to occasionally help out a customer integrate these products with our Weil-McLain Hydronic Heating Systems per our personal experience. Included has been converting Steam Boiler Systems to FHW and conjoining these systems.

    Note: We offer as an option full-size fittings (plugged) at our boiler supply and return points to integrate other boilers. Specify at ordering.

    The recent popularity of Outdoor Wood Boilers in particular has prompted many inquiries and discussions on our part. They seem however to neglect the interior-located solid fuel boiler in the scope of options. Each of these have distinctive attributes that both complement and complicate their integration and operational effectiveness.

    Inside or outside? That is the (first) question and may likely be answered by The Regulators (Zoning, Fire and Insurers). Specifically to wood/coal boilers:

    1. The Local Zoning Code will define permitted use and location parameters. (Outdoor Boilers are particularly vulnerable to NIMBY (Not In My Back Yard) and more specifically regulated.)
    2. The Fire Codes usually reference both, but are tough on Interior Boilers.
    3. Insurers (risk takers) then determine how much it is going to cost you to save money. Again, interior boilers take the major hit, especially if it is the primary energy source.

    Note: The delineation is between Gas/Oil-fired Power Burner Heating Systems and Solid-Fuel Fire (Coal/Wood, etc.) Systems. Insurers will usually bend for Automatic Stoker-fed Coal and Automatic Wood Pellet Systems with a two-week continuous-feed fuel storage supply. Check your local codes and insurers, however.

    At the risk of oversimplification and generalization we offer the following:

    TypeFlueLoop LengthLoop LossesStandby LossesEfficiency (Overall)
    InteriorReq'dShortLowLowModerate to High
    OutdoorN/ALongHighHighLow to Moderate

    Explanations:

    Flue:
    Any Interior Wood/Coal Heater REQUIRES A DEDICATED CHIMNEY FLUE! Flue quality must also be considered to support a continuous fuel fire. A “sometimes option” is to convert the primary powered burner (gas/oil) appliance to a “direct vent” device vs. the additional flue construction cost. Check it out.
    The Outdoor Wood/Coal Boiler has its own integral exhaust stack. However it is not unusual to see vertical stack added, sometimes up to 20 ft. to improve draft or smoke dissipation conditions.

    Loop Length:
    An Interior Wood/Coal Boiler can be readily be coupled to a FHW System, given flue location options. Interior Boilers are typically like-pressurized and therefore operationally compatible.

    An Outdoor Wood/Coal Boiler is typically “Zero Pressure” to simplify construction, ease of operation and complexity. This comes at a price with a continuously-powered, “high head” (flow resistance) system loop to the FHW System using a tough circulator. An in-line Heat Exchanger is required to mate the pair. Significant heat losses occur as well.

    Loop Losses:
    Interior Wood/Coal Boiler Loop Losses are typically dissipated to the ambient surrounding area and usually indirectly contribute to the heating of the structure.
    Outdoor Wood/Coal Boiler Interior Loop Losses are as prior, but Exterior Losses are very significant! (We have a system with over 400 feet of high quality, insulated two-pipe, buried down several feet. You can readily observe the reduced/absence-of-snow line path.) You must further isolate the “Zero-Pressure” Outdoor water from the interior “Pressurized” water using a “Plate-To-Plate” Heat Exchanger System with controls & circulators. This system contributes some heat to the ambient area, however.

    Standby Losses: (Defined as energy losses between heat demand cycles.)
    All Interior Boilers dissipate energy between cycles to the ambient and incur flue losses (heat up the chimney). The chassis and piping energy is generally accepted to be contributing to the heating environment positively excepting during the non-heating season.

    All Outdoor Boilers lose significant energy both from their chassis (never any snow on them) and their exterior service loop if circulation is not inhibited with demand. All this is lost energy by definition.

    Efficiency (Overall):
    Albeit being an empirical determination, the relative efficiencies of interior vs. outdoor boiler systems will be effectively higher due to their placements (in heat value areas) and reduced loop and standby losses. Thus the terminologies assigned and relationship to each other.

    Note: We are not addressing the Heat Generation Efficiencies of any boiler products in our discussion, these varying by configuration(s), but only their overall performance by type. Open the NH Climate Audit Calculator (Excel Doc). It’s a useful tool to both qualify and quantify your options by “playing the numbers”. Our “trick” is to calculate the “Cost per Million BTU” for a selected fuel, then adjust other fuel costs to equal your selection MBTU value. Remember to adjust your fuel appliance efficiencies if known or use the defaults. The resultant is a great “apples to apples” economic comparator!

    Operational Observations:
    Further observations of field operation leads us to believe that many outdoor boiler users fire them virtually continuously, incurring very poor fuel utilization, during low heat demand periods. Perhaps there is a continuing need for DHW (Domestic Hot Water) Generation without a storage means provided, or an unwillingness to build a new fire.

    We have evidenced outdoor wood systems consuming 11 cords of wood that in our humble opinion should be consuming no more than 5 cords with an interior boiler, 45% of the outdoor unit. Granted this is a very heuristic and unqualified determination, but yet an indicative one.

    Whatever the case, if one presumes to maximize his fuel utilization the household must adapt to the characteristics of the solid fuel fired system. “Showers-On-Demand” will likely require a generously sized Indirect Water Heater (Super-insulated DHW Storage Tank) to accommodate this lifestyle. Otherwise an incremental or even seasonal fallback to the gas/oil-fired system may be necessitated, and desirable.

    There is a tendency of auxiliary wood/coal users to “over-engineer” their systems. A prolific use of circulators, relays and controls result. We would respectfully suggest that exploring the use of Taco® Delta-T ECM Circulator Technology would benefit energy management. Further, employing Taco® Zone Sentry Valves with these permit some emergency (no power) gravity heating on interior boiler systems.

    Conclusions:

    1. Outdoor Wood Boilers appeal to users who have larger fuel demands, an abundant, low-cost supply of particularly cord wood, time and resources available to process it! (As we say: “Wood warms you twice!”) Higher equipment installation costs and poorer total fuel efficiency is a definite factor in their consideration.
    2. Outdoor Wood Boilers in particular require continuous electrical energy for combustion and distribution. No Power — No Heat! (Or it’s own a generator, too.)
    3. Interior Coal/Wood Boilers are operationally more desirable, but regulatory influences must be qualified and satisfied.
    4. Installed Costs of any dual-fuel system are substantial. To minimize this and achieve predictable performance, use of a qualified technical resource is recommended. Utilize a “system guy” and not just a “tech-sketch” provided by the boiler salesman.
    5. Not maintaining ideal and consistent heated water delivery in any system takes its toll on equipment, in particular circulators, through very long duty cycling.

    Our Personal System and Performance Data:

    Referencing our Blog on our personal system, we offer the following:

    1. Operating as an oil-only system between 1971-1975
      • Annual Fuel Oil Consumption: 475 Gallons x 140KBTU = 66.5MBTU/Yr @ 85% Efficiency = 56.5MBTU/Yr. Net Usable Energy
    2. Operated as a wood-only system between 1986-1995 (9 yrs.)
      • Annual Wood Fuel Consumption:  4-1/2 Cords average x 20MBTU/Cord = 90MBTU/Yr. @ 60% Efficiency = 54MBTU/Yr. Net Usable Energy
    3. Operating as a dual fuel system otherwise between 1975-1985 and 1995 to date. We have been using only a modest amount of wood in recent years, restricted by wood fuel costs and time constraints.

    2016/2017 Full Heating Season: 460 Gallons of Fuel and 1+ Cord of Wood + combustible paper & other waste, as available.  (Admittedly approximations.)
    10 Room Single Family Home, Built 1970, Heated Area: 2,016 Sq Ft
    3-1/2 Zone, Programmed T-Stats, Coupled FHW Oil and Wood Boilers. DHW Immersion Coil on Oil Boiler. Planned Upgrade: Large Indirect Water Heater (HTP SSU-80) for DHW to permit less low/no heating season boiler cycling. TBD.
    Annual Degree Days: 7,500 Average (SW NH)

    Comments:

    Dual-fuel and in particular interconnected FHW boiler systems offer a good heating option, given they be properly configured and operated. We have a long ways to go however to inform and guide customers in their economics, application and execution. It is our hope that this document is of some help toward this end.

    Author’s Note: Updated 10/13/2017


  • HEATING FUEL SELECTION – FROM AN ENGINEER’S PERSPECTIVE

    Heating fuel selection has become more than a casual topic in this currently tenuous economic situation, and likely to be an extended one. Unfortunately the picture is both clouded and distorted by the contemporary economic, political and media rhetoric. From an engineering perspective however the overcast is dissipating and the stars are beginning to show.

    As Sgt. Detective “Joe Friday” (Jack Webb) of the old TV Series “Dragnet” would retort upon questioning a witness, “Just give me the facts, Ma’am. All I want is the facts.” So here they are.

    From our Physics 101 Textbook: All physical matter exists in three (3) states: Gases, Liquids and Solids. Hold this thought.

    Our Chemistry 101 Textbook was divided into two (2) Sections: Inorganic and Organic Chemistry. Organic chemistry is dedicated to the properties of carbon, and in particular the C-H (carbon – hydrogen) bond and its chemical interactions. It is so important as to warrant its own science. There’s Carbon ….. and there’s everything else!

    Carbon compounds all occur in nature (predominantly in the earth) in all of its states as gases, liquids and solids. Due the energy content of the C-H bond they are all potentially direct heating fuels, or for the creation of other forms of energy, in particular electricity.

    What primarily differentiates the states of fuels is their “Energy Density”. (How much energy is contained in a comparable volume of material?) Therefore, as naturally occurring heating fuels they are:

    1. Gases: Natural Gases are the lowest density fuels.
    2. Liquids: (All Petroleum) Heating Oils are mid-density fuels.
    3. Solids: Coal is a mid-density fuel, comparable to oil, but solidified.

    There could be another category of “Renewable Solids”, made up of surface harvested fibrous materials such as Wood, Peat, Corn Stover, Peanut Shells, etc. These have much lower energy densities, somewhere between gases and liquids. You might consider these as “fuels of opportunity”, based on locales.

    None of these fuels as harvested below or above the ground can be directly converted into a heating fuel without further processing. They must be economically converted and moved to their points-of-use. This takes energy in varied forms, depending upon their specific fuel attributes.

    The Gases:

    Natural Gas is the predominant subterranean gaseous fuel and can be directly combusted for its heating value. Distribution and safety are the primary considerations.

    Having no smell, a trace gas must be added to all fuel gases for detection. That “stink” is a life saver! Gaseous explosions are memorable ones indeed.

    Natural Gas must be piped to its point-of-use. This piping infrastructure is large, extensive and expensive, supporting the movement of huge volumes of a very low energy density fuel over long distances. As a “distributed” fuel (similarly with electricity) these costs are burdened onto your energy bill, typically along with additional service and maintenance charges.

    IMPORTANT NOTE: Whenever doing fuel cost comparisons, you must solicit an estimated billing for Natural Gas and Electricity Service. The “Per Therm” or the “Kilowatt-Hour” (KWH) fuel unit cost IS NOT YOUR FUEL BILL! Locally (NH) we factor (multiply) by 1.5 to 2.1 seasonally for an estimated billing.

    Liquid Propane (LP), Liquid Natural (LNG) and Compressed Natural (CNG) Gases are concentrated, higher energy density fuel products achieved by composition, chilling and/or compression of gases into a tanker or tank for distribution. As such these become “delivered” products that are billed by-the-gallon or by-the-tank only.

    There is a significant amount of energy required to transform gases into usable liquid products, thus a much higher unit cost. Delivery costs related to tanker-to-site-tank or individual “bottle” deliveries are also factored into the unit cost.

    An on-site stored energy gas source must also be weighed, where applicable.

    All gases can be combusted very efficiently utilizing the latest “condensing” technologies. These are routinely 95+%. It must be accentuated however that the equipment investment is costlier than alternatives and must be factored.

    The Liquids:

    Petroleum Fuels (Carbon-based) being liquids have an inherent advantage over their gaseous or solid cousins. They can be pumped, poured, piped, tanked or transported with less energy and at substantially less risk. Only bulk barging or training of coal can compare, and then only to bulk use sites.

    Petroleum as extracted is a varying mixture of liquid and gaseous carbon-based products, readily separated by heating in a “Distillation Column”. Gases rise to the top and Tar sinks to the bottom. All are “skimmed” at their various levels. This is a relatively simple “first pass” process, but yields a ratio of products.

    The C-H based chemistry yields more. By introducing selective products under heat and pressure you can “polymerize” (chain them together) to make denser, heavier products or “fractionalize” (break them apart) to make lighter and gaseous products. Very high yields of usable fuel and lubricant products result.

    Heating Oil fuels combust efficiently in a modern, atomizing power burner. Peak is about 87% efficiency, depending both upon the appliance and the composition of the oil itself. Natural contaminants such as nitrogen and sulfur preclude higher values. Recent “Bio-Heat” Oil development, blended from harvested, carbon-based stocks will improve combustion efficiency somewhat. This along with “Fluidized Bed” and similar technologies promise even higher future combustion values.

    The Solids:

    Coal: Our discussion of C-H based solids must necessarily be limited to Coal. There are two (2) major derivatives, namely anthracite and bituminous, but energy-wise they are arguably similar. Functionally they process and handle much the same. Anthracite is the preferred variant in volume combustion applications, however.

    Coal requires considerable extraction and granulating energy, offset by the low material cost in situ. It bulk handles and transits readily and inexpensively, but its combustion characteristics relegate it to continuous-fire applications. Thus it predominates in electric generation. It handles very safely as well. When have you ever heard of a coal train catching fire?

    The Renewable Solids:

    Referring to our prior mention of these predominantly fibrous, harvested fuels, suffice to say that only wood is regionally viable and a great “sweat equity” fuel. It is also a natural by-product of our wood-harvesting industry. To quote that old New England adage: “Wood warms you twice”. We don’t foresee any significant deforestation resulting.

    Further, the quoted lower efficiencies for wood are aggravated by the need for moisture content control (air or kiln drying) and necessarily long and moderately controllable firing cycles. It is truly only a “fuel of opportunity”.

    The Current Heating Fuel Situation:

    By “situation” we mean what economical fuels are viably available and where are they located? The “what” and the “where” are inevitably linked.

    By any measure the United States is most bountifully blessed with all resources, with the least being not only our current heating fuels, but our future ones!

    The near-term picture is punctuated by our excesses of both natural gas and petroleum (oil) that have depressed heating fuel pricing dramatically. Despite a depressed economy a fervent effort is on to convert particularly oil-fired installations at all levels to natural gas, where available. We have within the past two heating seasons seen incremental fuel cost crossovers of oil and natural gas within the $45-48/bbl crude oil range.

    Natural Gas and Petroleum have become so plentiful in fact that we are net exporters of both fuels. The “World Price” of 4 to 5 times our domestic of Natural Gas in particular is just too good to ignore. It won’t hurt our trade imbalance either.

    It is no understatement that “fracking” (hydraulic fracturing) as touted in the technical journals is likely the most significant American Invention since the Computer. The world energy picture has changing dramatically, and for the good. This technology is applicable to both gas and oil exploration and production.

    We currently have about 50,000 miles of fuel pipelines operating in the U.S. The Canadian Athabasca (Oil Sands) extension known as the Keystone Pipeline is happening along with the Bakken Basin and others. Several U.S. and one (1) Canadian pipeline(s) are being reverse-flowed to support both this and the new Greater Mid & South West Fields. We are currently exporting some highly refined oil products to Europe from the East Coast. Delta Airlines recently purchased a New Jersey refinery for its dedicated jet fuel production. (Smart move!)

    We are now at oil parity and less subject to the fickle “World Oil Market” (OPEC). As we expand the ball game will change significantly. To accentuate this point: The current price of natural gas (energy-wise) is equal to an oil barrel-price of $15, or a gasoline price of less than $1.50 per gallon. Will we get there? Unlikely, but we are heading in that direction. The current barrel-price of $45 is expected to stabilize, barring world influence.

    Thus, the current and near-term heating fuel situation is substantially “business as usual” with a notable sag in heating oil pricing with natural gas applications expanding disproportionately. Heating oil cost is crossing over with natural gas, even as a delivered vs. a distributed product. Sharpen your pencils when you shop!

    Coal remains in plentiful supply! Without addressing the EPA Regulations, etc. it remains our significant electric power generation fuel as well as a selective heating fuel. It is a bargain where natural gas is not available, if you can utilize it. Note: We are now exporting coal to Asia and Eastern Europe.

    The “Crossover Fuel” Period: (the term is ours – and at our risk?)

    The disparity in natural gas supplies and pricing vs. the oil supply limitations and volatile pricing is breeding an era of “crossover fuels”. These will virtually all be based on Natural Gas in both gaseous and liquid states as a seed fuel. It will be combined with other gaseous, liquid and solid fuels to create oil product supplements for the transportation and in lesser degree the heating markets.

    This fuel availability phenomenon will precipitate a series of these products within a relatively compressed time period. None of these are “rocket science”, merely scaling existing technologies as market opportunities are presented. The following are just a few of these, but the likely leaders:

    1. Compressed Natural Gas (CNG): As a potentially more broadly applied transportation fuel, it is a real winner. Currently being used in Utilities Service Vehicles, its logical and economic extension to all mid-range (up to 200 mi radius?) fleet and service terminals (private and government) will have a major impact. The offset loosens up general oil supplies, including heating fuels. (This is also BillionaireT. Boone Pickens’ new pet project. He took an admitted $150M “hit” on now abandoned Windmill Projects. Looking to make his money back in a hurry we presume.)
    2. Oil from Natural Gas: There are several processes that can make oil from plentiful coal as well as lesser feed stocks. We are not familiar with the specifics excepting that plentiful gas next to plentiful coal seems to be a bench-marking enterprise.
    3. Alcohol from Natural Gas: Alcohol as a fuel has not been mentioned thus far. Its current notable application is as a beneficial gasoline additive. A C-H-O (Carbon-Hydrogen-Oxygen) Compound, its energy-density is less than oils, but burns cleanly and very efficiently. It is a superb racing and automotive (E85) fuel IN A SPECIFICALLY DESIGNED ENGINE! Ethyl Alcohol (Ethanol) is readily manufactured by process combination of natural gas and carbon dioxide (CO2) from the atmosphere. CO2 is that nasty (?) stuff that creates global warming (?). Estimated Cost: $1.50/gal.
    4. Alcohol from Coal: Referring to Items 2 & 3 preceding there is a proven, scalable process for producing alcohol from coal using natural gas. Estimated Cost: $1.50/gal. Note: Alcohol is not currently used as a heating fuel. The cost and energy-density vs. heating oil has not been advantageous. Secondly, the current heating oil process equipment would have to be modified for its use. A diaphragm-style fuel pump or similar device would need to be employed for atomization. (Alcohols are not intrinsically self-lubricating.) Otherwise there is no process reasoning to negate its use as a heating fuel.
    5. “Fuels of Opportunity”: This is the Etcetera Bucket that contains all of those development projects that ultimately produce oils or alcohols. There is a seeming plethora of these with few in scalar production. Notable are the alcohol producers:
      • Corn Ethanol Fuel Supplements– Gasoline additives (E10, E15 & E85) production by farm co-ops and independents.
      • Cellulosic Alcohols– Produced from fibers and by-products of surface agriculture.
      • Oil from Coal– High Temperature/Pressure Steam Injection into Coal Process. No cost-to-benefit analysis available. South Africa produces.
      • Etcetera – The list goes on.

    General Note: There may be a few winners, but a lot of losers in this alternative energy crap shoot. The Natural Gas glut will skew the results.

    Summary Notes on Current Heating Energies:

    1. Natural Gas will generally predominate, where available.
    2. The Oil vs. Natural Gas pricing gap has closed, returning to par for the next few years.
    3. LP (Propane) Gas will remain a “fuel-of-choice”.

    Near-Future Heating Fuels:

    Looking forward near-term in heating fuels is a simple matter. More of the same. There is nothing save the Natural Gas to Oil cost gap closure to talk about. You must also accept that common Heating #2 Fuel is close to Diesel Fuel and necessarily follows its pricing trends. (#2 Heating Oil is dyed Red to deter Diesel Tax Skippers from using it in their cars and trucks. Fine resulting when caught!)

    The giant strides in efficiency made in the past ten years or so in heating appliances will be tempering. There’s just is not much more to be had in particular with gas efficiency to play with. Oil efficiency continues to address its composition problem.

    Recommendation: If you’ve been procrastinating, waiting for that world-beater boiler or furnace to appear, don’t hold your breath any longer. Invest in that 95% Condensing Gas or 87% “Triple-Pass” Oil Boiler. Stop “throwing good money after bad.”

    The Future Heating Fuel: Nuclear-Generated Electricity

    Surprised? You shouldn’t be. Electricity is the simplest and most efficient means of generating, distributing and utilizing energy. Problem is that we don’t generate it efficiently enough. We do a fair job with hydroelectricity and maybe geothermal, then we get loose. But even these are not really good enough.

    Back to Energy Density. The C-H Bond energy potential is the basis for all of our fuels. The energy-density of a Nuclear Fuel is 1 to 2 times 10 to the 6th power or 1-2 million times that of the C-H Bond! So why don’t we have cheap enough electricity? The wrong nuclear technology. We developed and then abandoned the correct one in the 1970’s in favor of uranium and plutonium based processes – to build bombs with their by-products.

    Thorium LFTR Reactors are being aggressively developed by Russia, China and India, with our technology! We must have them to project our Medical Isotope, NASA Deep Space Programs and as a DOD Modular Power Source at minimum. We’re looking at electricity costs of less than $0.01 (cents) per KWH! Check your current electric bill.

    For your Homework, read up on Thorium. It’s our future.

    Last Edit: 09/07/2017 pdm


  • INTEGRATING A WOOD OR COAL BOILER WITH FHW (HYDRONIC) SYSTEMS

    Making that wood or coal fired boiler perform well when coupled to your gas or oil fired FHW heating system can be a challenge. They just operate differently. Only by knowing their characteristics and utilizing them to advantage can we affect positive system behavior.

    An automatic, powered FHW system necessarily attains a high water temperature (just below boiling) during heat demand for heat transfer efficiency. The heating system is pressurized (like your automobile) to enhance circulation and increase the boiling point. Controls adjust burner operation to compliment demand levels (instant on-off). Your radiation is sized to compliment its heat generation capability.

    A coal or wood boiler has a far different firing (heating) profile. Their fuels have “burning stages”, typically ignition, charcoaling (wood) and gasification. Each stage increases combustion temperature (and efficiency). Maintaining a fire necessitates replenishment (mixing) of new fuel, continually changing the heating profile. This can be moderated and controlled in degree by sizing, i.e. wood pellets vs. split firewood or rice coal vs. chunk. In either case, the fire is modulated by air and draft control.

    Note: Exterior Coal and Wood Boilers are typically “Zero Pressure”, necessitating a water-to-water heat exchanger to couple to the typical 12-15psi FHW System. This will require an additional controlled, properly sized and powered circulation loop.

    The major control element of an integrated system is the FHW Boiler Master Aquastat, controlling powered system temperatures and burner operation. It is typically designed to operate in a narrow and high temperature range for efficiency. This must be widened to accommodate the fluctuation in solid fuel delivery or your burner will be cycling often and shortened cycles. (Tough on equipment as well.)

    You will have to check the specifications of your Master Aquastat as they vary widely with your system type. Briefly,

    1. If you have an Immersion Coil to generate DHW in your boiler, your Aquastat is a “Triple Action” or “Ranging” Type that maintains temperature with a modest, adjustable temperature differential.
    2. If not, your boiler provides only heated water for area heating of your home or structure. It has (or should have) a “Cold Start” Aquastat that only fires the boiler when heating is required. Otherwise the boiler cools down between cycles, approaching ambient temperature. Additionally,
      • Older systems will likely have narrower, fixed differential controls.
      • The newer, high efficiency boilers will have adjustable or programmable digital controls. Check specifications again.

    Your Master Aquastat should have a fully adjustable temperature range, wide, adjustable differential(s) and mode switching to compliment coal or wood boiler interaction. We employ the Hydrolevel Model 3150 Universal Aquastat exclusively:

    Specifications: http://www.hydrolevel.com/pages/new.html

    Installation: http://www.hydrolevel.com/pages/pdf_files/HydroStat.pdf

    It does everything, and well. You can “range” up to 30 deg F on the high and low ends, inhibit burner within high range and cut off at low limit (mode). Nice, visible display!

    Check one of our site photos for interfacing and general piping details (powered boiler).
    Link: http://www.merchantcircle.com/business/Mercier.Engineering.603-588-2333/picture/view/2875310

    This provides your basic interface, but more is required, particularly hydronically.

    Particular attention must be paid to the operational habits of your coal or wood boiler, particularly in ultimate temperature control. Can you fully fuel it when the boiler is red hot and walk away unconcerned? If over-firing is undesirable, you must dissipate this excess energy somehow. Options:

    1. A “Dump Zone” – Actuate heating zone(s) automatically through an in-line high limit “make-on-rise” Aquastat. They can be normally or optionally heated zones. Result is an overheated house, basement or garage, or all. Wiring this option can be tricky, however. Watch your control wiring. Add isolation relays if in doubt.
    2. A “Dump Tank” – Configure a storage tank in parallel with the feed lines to the FHW Boiler. Depending upon your physical layout and attributes it could also be behind and near the solid fuel boiler to act as a direct “Tempering Tank” to it. Between the boilers it can function as extra heating capacity, in degree. Again, take care with your circulator circuit and temperature sensors.

    Note: Reading our blog entitled OUR UNPOWERED FORCED HOT WATER (FHW) GRAVITY HEATING SYSTEM may be of some help in this regard, where applicable. Employing gravity elements used in our personal system takes some expertise and effort. BE CAREFUL!

    To further control inhibiting the burner at a lower temperature than the 3150 ranging allows may require placing an immersion style (where boiler provision is available) or a “strap-on” style Aquastat on the inter-boiler loop. This would be a “make-on-rise” Aquastat configuration.

    Another option is a manual one – placing a switch in series to the burner wire and located conveniently. Just don’t forget to turn it back on before you go on vacation!
    Operation requires “tweaking” of controls and in particular of temperature and differential settings. Heating demands vary widely with external temperature, lifestyle patterns and solid fuel firing schedule. If you still find that your FHW Boiler is cycling too often despite your best efforts, look at your total boiler water capacities.

    EXAMPLE: We have a client who is attempting to supplement in a larger home using a Chunk Stove with an internal water coil. The system has such low water capacity that if he delivers water at a reasonable heating temperature it is short cycled. Water temperature is either too cool, correct for a short period and tripping the “Dump Zone”. The quick patch is to install a “Dump Tank” with circulator-loop controls to accumulate energy along with aggressive firing of his chunk stove. Even then it will only be modestly effective – unless he wants to fully occupy himself in the basement.

    We alluded early on to radiation capacity as a concern. Radiation is designed to operate at a high, normal FHW heating temperature of 180-190 deg F. Lowering this temperature necessarily lowers heat delivery significantly. If your FHW System was slow to warm your home, it isn’t going to get better with a solid fuel boiler’s varying, if not lower delivery temperatures!

    Newer homes we find are radiated so closely to peak cold expectation as a cost constraint that a solid fuel boiler supplement may be disappointing. Older home FHW Systems on the other hand tend to be better radiated by design – and – home energy improvements have reduced their heating demands, effectively increasing radiation capacity! Their original boilers if still in use also exhibit this over sizing effect, coupled with the earlier tendency to oversize them more aggressively by design.

    So, if you are having difficulty maintaining warmth you have a few options:

    1. Increase the water capacity of your system with a “Dump Tank” to hopefully provide a damping effect against deep day/night fluctuations.
    2. Qualify pipe sizing and routing compliments boiler capacities.
    3. Verify that capacity of your solid fuel system is adequate.
    4. Increase the radiation capacity of your home, proportionately for maximum comfort. You can always close registers to cool selective areas, but not to increase others.

    Note: Use a Heat Loss Calculator to qualify items 3 & 4 above! (See our Blog.)

    We have purposely omitted piping and electrical diagrams from our discussion. There are just too many factors and system configuration details to present generic solutions. This is where a qualified heating technician or engineer should assist you to obtain a successful outcome.

    An integrated system while offering a likely significant benefit in heating cost reduction does present its own operating characteristics:

    1. Circulator run time is significantly increased due to lower average system temperatures. Expect a modest increase in electric cost with more wear and tear on circulators and controls over the longer term. Keeping a spare circulator on hand is probably a good move for a DIY.
    2. If you use Setbacks with a Programmable Thermostat, be prepared to adjust not only the setback temperature but the times to “lead and lag” for comfort. Experimentation here.
    3. If you don’t utilize the wide differential range of the recommended Master Aquastat and install a second Aquastat to inhibit your FHW Burner at a lower temperature, you may exhibit significant heating lag. Adjust your temperature set point upward to moderate this condition (or listen to the “cold blooded” complain).
    4. Exterior Boilers in particular are vulnerable to power outages. A small backup generator in any case might be a judicious move.

    Hopefully this introductory discussion will help toward this end. You may also wish to read our other blogs to fill in more detail and explanation.

    Last Edit: 10/10/2012 pdm


  • DOMESTIC HOT WATER (DHW) GENERATION – YOUR OPTIONS

    We just returned from a hardship “no heat” service call. These folks are obviously up against it economically, as are many these days. However they recently substituted an electric water heater for their boiler immersion coil to generate domestic hot water and hopefully reduce their summer fuel bill. Now they are concerned about the increase in their electric bill as a consequence.

    This brings up the timely subject of options available in DHW generation. Please refer to content in our other blogs, specifically related to energy source selection, tempering tanks and using a Heating Cost Calculator. For the latter we use the NH OEP Heating Cost Calculator at http://www.nhclimateaudit.org/calculators.php. There should be equivalent calculation tools available for your region.

    Heating Cost Calculators don’t lie. They provide a unit energy cost per Million BTU’s for each fuel. You should apply an appropriate AFUE (Energy Efficiency Rating) for your or the best competing appliance by fuel type to get an accurate comparison.

    By calculation DHW heating fuels from lowest to highest costs are: (NH Region)

    1. Natural Gas – Rate factored by 1.5 to 2 for actual billing. (Divide total fuel billing by actual fuel charge for factoring.)
    2. Fuel Oil
    3. Propane
    4. Electricity – Must be also factored for actual billing. Ours is 1.85. (Varies significantly by Provider & Region)

    Note: 1&4 are “distributed fuels”, necessarily incurring varied pipeline and distribution service costs.

    Natural Gas has been historically the most efficient fuel for both heating and DHW generation vs. fuel oil until recently. A very rough crossover is a $45/bbl Crude Oil Price. Local fuel market variations and appliance installation costs must be considered. Propane, a manufactured fuel, is by comparison a significantly higher cost product. This is unfortunate in that they utilize the same appliances (with minor modification) with similar efficiencies. Propane fuel cost is a killer!

    Fuel Oil and Gas Heating Appliances provide the same function, however differing significantly in configuration to accommodate their particular combustion characteristics.

    Electricity despite its extremely high energy efficiency is offset dramatically by unit cost. Electric Water Heaters are enticingly priced, too. Too bad.

    We are considering only the intermittent combustion fuels (oil and gases) in our analysis. The continuous combustion fuels such as wood, coal, etc. suffer by nature to being very inefficient DHW generators. This is not to allow that these fuels fired in boilers can provide seasonal DHW to Indirect Storage Heaters or coupled to a central boiler with an immersion coil. Although increasing in rural popularity, they don’t represent a significant market segment to date, nor likely will they ever.

    Gas and Oil Combustion Appliances are limited to Boilers and Water Heaters. Their configuration options are similar with the exception of the Gas “Demand” Water Heater and are as follows:

    1. A “stand-alone” (dedicated) Oil or Gas Water Heater. These are a virtual necessity when the central heating appliance is Forced Hot Air (FHA). The stand-alone Oil-fired Hot Water Heater has suffered from poorer fuel efficiency by design and has been limited to high demand users such as restaurants, etc.
    2. The Gas “Demand” Water Heater – A unique, hang-on-the-wall device, it stores no heated water but fires only when DHW flow demand is detected. It is very sensitive to water conditions, including acidity, contamination and lower delivery temperatures.
    3. A Central Heating Boiler with an Immersion Coil therein to create DHW.
    4. A Central Heating-only Boiler coupled to an Indirect Water Heater (Super-insulated DHW Storage Tank). Provides higher efficiency in both heating and DHW generation. Significantly increasing in popularity.

    The Gas-fired “On-Demand” Water Heater has a distinct DHW market application, subject to several limitations:

    1. They are “pricey” relative to other options.
    2. Initial DHW delivery is mildly delayed during warm up.
    3. Long cycle demand capacity reduces with supply water temperature decrease (colder water from source).
    4. Annual chemical treatment to control sedimentation is required to maintain performance.

    Note: Both the Gas “On-Demand” Water Heater and Boiler Immersion Coil Systems mentioned can benefit from a “Tempering Tank” placed in line with their water supplies. (Reference our prior blog on these.) It’s a non-insulated accumulation tank that allows water to acclimate to ambient (room) temperature before entering the DHW heating device. Increases heater performance significantly by temperature and delivery maintenance over total cycle demands.

    Otherwise, Indirect Storage Heaters are the path to efficient DHW generation and storage – regardless! They compliment lifestyle variations and usage patterns when coupled to an efficient heating-water-only generating device, commonly referred to as a “Cold Start” Boiler. It fires ONLY when area heating or DHW recovery is demanded. Otherwise they revert toward ambient temperature, saving significant “standby losses” when not in use. There are several options to “getting there from here”, depending upon your situation.

    1. Purchase a High-efficiency “Heat-only” Boiler and Indirect Water Heater as a package and be done with it.
    2. You can convert your existing Immersion Coil System Boiler to a “Cold Start” Type by:
      • Changing your Master Aquastat Control to a “Cold Start” Unit
      • Adding an Indirect Water Heater with its own circulator or valved zone.
    3. Couple an Insulated DHW Storage Tank to your current Boiler Immersion Coil with a POTABLE WATER CIRCULATOR ONLY (Stainless or Bronze) and Temp Aquastat Zone in the loop. Substitute a “Cold Start” Master Aquastat to convert your boiler to a “Heat-only” as in Option 2.
    4. Do Item 3, but convert a good 80 Gal. Electric Hot Water Heater into a Storage Tank. Strip its wiring and utilize the upper, internal Thermostat Switch as a DHW temp control. Note: This last option is the “Cheap Trick”. It costs significantly less to install, despite the pricey circulator requirement. DHW piping is typically run in parallel with the immersion coil with a flow check function.

    Whenever employing ANY Storage Tank for DHW, place a Thermal Expansion Tank in-line on the cold water supply line! Heating cold water expands it, creating pressures well above the supply pressure and potentially bursting the system. This is particularly evident in municipal or well supplies where there’s a check valve in the cold water service. Cheap insurance!

    So, using the appropriate fuel costs from a Heating Cost Calculator and reviewing your current or planned appliances, plan your Heating and DHW Systems together for best efficiency.

    Last Edit: 06/24/2017 pdm