• Tag Archives Heating
  • WHAT IS A GRAVITY HEATING SYSTEM? – Gravity Convection Heating Revisited

    The three (3) basic elements of hydronic heating are heat generation (boiler), distribution of energy (pumps) and conversion to area warmth (radiation). Of these hydronic distribution is typically the least understood, generally misapplied and needs revisiting.

    What is a Gravity Heating System? A century ago all water-based hydronic heating (hot water and steam) employed the natural gravity attributes of heated water and water vapor (steam) to distribute energy. NO DISTRIBUTION ENERGY WAS REQUIRED! These were effectively single-zone systems that could only be modulated by varying the energy input of the boiler and the radiation outputs using register dampers or steam radiator vents, respectively. Natural (gravity) convection of heated water underlies all hydronic distribution, yet is not considered in contemporary practice. So, check-valving is installed to negate its less desired effects.

    The introduction of electric circulation pumps in the 1920’s enabled forced hot water heating (FHW) and changed hydronics forever. Gone was the large, pitched piping and radiators, replaced with zoned heating and finned radiation. The heating market never looked back, and justifiably so. Underlying this however remained the natural gravity convection effect that had to be controlled using check-valving as noted within the system.

    Early electric circulation pumps (circulators) were large, power consumptive and constructed of discrete components, i.e. motor to coupling to pump. We “old-timers” have vivid memories of failed couplings of varied types, seized and leaking pumps and smoked motors. The advent of wet-rotor circulators was like manna from heaven, reducing circulator issues with greater longevity and reduced power consumption benefits.

    Now the evolution and introduction of particularly Delta-T (differential temperature sensing) ECM Circulators projects hydronic distribution management to an entirely new level. Integral instrumentation and operational data display of these circulators provide us with finite attribute identification and application control.

    The focus of our work has been to optimize this hidden contribution of natural gravity convection as both a distribution energy saver and a selective fail-mode feature in hydronic heating. As such the Delta-T ECM Circulator has been the crucial tool in the development of our “Delta-T ECM Hydronic Heating Appliance”. We claim optimization of natural gravity convection within our boiler, near-boiler distribution piping and distribution energy requirements using a dedicated Delta-T ECM Appliance Circulator. Citing an automotive analogy, we refer to it as “putting an Automatic Transmission on a Boiler™”. This intelligent, variable speed circulator is effectively a hydronic CVT (Continuously Variable-Speed Transmission) in practice.

    Let’s go back to that old gravity hot water heating system of a century ago. By comparison, contemporary hydronic heating systems have smaller piping with multiple zones for heating flexibility. The old “gravities” necessarily used high-mass cast-iron boilers to modulate heating supply, otherwise control was particularly difficult when using solid fuel firing as with wood or coal. With generous distribution piping sizes and radiation elements gravity convection worked fairly well, and with NO distribution power requirements!

    Properly pipe a contemporary FHW system using a dedicated “Delta-T Mode” system circulator with complimentary low-energy ball-type zone valves vs. flow-checks yields great results! Transpose this configuration onto the old gravity system layout and you functionally emulate its performance as in the following figures.

    The advantage is in using natural gravity circulation in this contemporary upgrade. Today we have somehow lost the trade skills of enhancing gravity convection. No consideration is given to pitching, compacting and minimizing distribution piping in particular. Additional gains are available in radiation layout by using properly sized and configured series and/or split radiation loops. The 45° elbow fitting as an example saves 30% of piping and reduces head pressure significantly over a 90° elbow run. All this increased pipe volume and head pressure reduces the natural gravitational convection effect, not to mention increasing materials, labor and lifetime operating costs of the system.

    Our Delta-T Mode Circulator measures this head effect well via its wattage indicator. All of our single, dedicated system circulator Beta Site installs to date exhibit an 8 to 13 watt distribution power consumption upon a 20° delta-t (adjustable) differential attainment. Compare this to 80 watts typical for each 16gpm fixed-speed circulator or 20 to 25 watts each for the equivalent delta-t or delta-p install. With delta-t you can witness the wattage steadily decay to half or less as natural convection contributes. We refer to this as “paddling your canoe with the current”.

    A secondary effect of gravity convection seems to be radiation heating profile modification, smoothing demand amplitude variation and increasing comfort. Some of the extended fuel savings we observe and the delta-t manufacturer claims seem to be due largely to this radiation profiling effect. Another contributor is the lowered system operating temperature effect of using a very high mass cast-iron boiler vs. contemporary low-mass units. Burner operation cycles are significantly less frequent and briefer than the system it replaced.

    A personal observation: This author has never replaced a “cold shot” cracked or magnetite impaired cast-iron boiler in over sixty years of hydronic and steam installations! Perhaps a discussion for another day, but have we also “thrown the baby (cast-iron boiler) out with the bath water” to cite an old adage?

    Finally, the combination of higher boiler thermal mass with enhanced gravity convection extends selective fail-mode heating continuity substantially. Recently and four years prior our Beta Site #3 experienced a fail-safe circulator interruption. The latter an over-current condition from a voltage surge “fail-safed” its operation. In both instances the condition was not discovered for an estimated 2 to 3 days, despite significant heating demand. Neither living area heating nor indirect DHW generation were affected. Second level heating reduction was eventually noted, as it was prior. The customer called and we reset the power switch over the phone to resolve. It is also noteworthy that we have had no system related service calls in over twenty aggregated operating years on our multiple Appliance Beta Sites!

    In closing, the contemporary excesses and misapplication of hydronic distribution are troubling to this author. If tradesmen are promoting their excessive system distribution piping efforts as efficiency measures they are sorely misdirected and possibly even deceitful. Witnessing customers proudly showcasing excessively installed systems or trade supplier contests for the “prettiest system” installation pics are also particularly disconcerting. Trade practices and hence consumer perceptions need challenging. Are we selling parts ….. or performance?

    Perhaps it is time for an engineered “appliance” approach (as ours) to rein in this “Plumber’s Playground”.

    Updated 08/23/2019 P.D.M., Sr.


  • HEATING A CHURCH – Warming Up The Congregation

    Heating a church is seemingly always a challenge. Whether it’s the structure’s physical attributes, the climate variations, the occupancy schedule and warmup demands, no two are alike nor can they be treated as such.

    Oh, to turn back the clock a few centuries when most churches including the Great Cathedrals of Europe were unheated! Shivering through a lengthy sermon must have certainly tested the faithful. However, we have become sensitive to our comfort in modern times including group participation in religious activity. “Passing the plate” to pay the fuel (heating or cooling) bill is particularly noteworthy to the congregation and usually a topic of comment.

    The scope of our discussion will be limited to and focus upon improved heating of a church (or similar structure) via enhanced air handling. In our experience most congregations have focused on cooling enhancement by adding ceiling cooling fans and employ them to more aggressively circulate air with or without air conditioning. Now revisit a church during the heating cycle ….. and the fans are still! Why?

    Heated air warms people, and eventually the structure. Seat yourself on a cold pew bench or metal chair when it seems that the air around you is reasonably warm and you will get the message. Add the practice of doing temperature setbacks between occupancy to conserve fuel (customary in churches and meeting places) and you aggravate the warmup process. Some of this can be alleviated with the use of Programmable and WiFi Thermostats, but even these cannot address the underlying issues of efficient heated air distribution, our topic.

    As simple and as obvious as it may seem, heated air rises! Any contained structure, heated or unheated, exhibits a higher temperature at its top vs. its base. Whether it’s a fully “vaulted” cathedral or an arctic igloo, the effect is measurable. No complaints from the choir loft in a cathedral, by the way! An extreme can be found in a high-bay warehouse where seasonal upper temperatures can reach above 140°F, an immediate personnel health endangerment. It must therefore become obvious that we must turn on the fan(s) to advantage the heating situation, but how and when?

    Virtually all structures employ perimeter heating, i.e. placement of heating radiation or air registers around the exterior walls and usually somewhat positioned under windows where feasible. Heating radiation and heated air registers induce “convection” or natural rising and circulation of heated air by diffusing it with the cold air emanating from windows and exterior walls to eliminate their cooling effects. This heated and “mixed” air rises toward the centered ceiling or higher “cathedral ceiling” area creating natural convection and diffusion. Depending upon the individual structure attributes and aggressiveness of the radiation delivery there is always a level of lamination at the center/peak that can be advantaged by forcing it downward to mix and accelerate the heating process. The following pictorial is offered:

    Figures 1 & 2 above depict natural temperature lamination and convective flow of a perimeter-heated structure.

    Heating elements are purposefully placed against lower exterior walls to induce thermal convection while diffusing (mixing) with cooler air off the exterior walls for greater comfort. However, lighter heated air rises and accumulates at the ceiling levels, stratifying the air mass above. Cooling uppermost air gradually sinks and diffuses with lower, forming a midway convective path as depicted. Natural convection is never complete and the structure’s air mass is always significantly graduated temperature-wise from bottom to top.  The “vaulted” or “cathedral” ceiling in Figure 2 accentuates this condition, as coloring depicts. We must use forced convection (blowers or fans) to advantage ourselves.

    Our contention can be readily proven by switching on your present summer cooling fan(s), rotating to force air downward and adjusting until a modest air movement is felt. Turn on your heating thermostat and you will note a significantly quicker time-to-temperature resultant. The initially laminated air mass is diffused and then mixes with newly heated air to approach a more uniformly heated air mass. Ideally you should leave the fans on during the occupancy period, irregardless of thermostat demand cycling. It should be obvious that if circulation as described is not attainable, fan resizing and positioning may be necessary.

    Fan operation should be integrated into the heating system to maximize utilization and efficiency. The techniques must differ to suit each basic system type.

    1. Boiler-based Forced Hot Water (Hydronic) or Steam Systems are relatively simple to integrate. Trace the supply line from the top of the boiler outlet to the radiators or baseboard in the fan-located heating area.

    a. Place a heat-sensing “strap on”, “close on rise” aquastat such as the appropriate Honeywell 4006, 6006 Series on this supply line. Re-wire the power feed to the fans through the aquastat.

    b. Set the aquastat at 120°F as a starting point. Adjust in operation to suit. The lower the set point the longer pre-heat and post-heat fan operation to initially diffuse and then maintain comfort levels during cycling.

    2. HVAC Systems require a little more sophistication. Consult with a qualified technician to ascertain the proper strategy for lowering and lengthening system air delivery rates and timing.

    Note that an alternative control method is using a kick-space heater thermostat to switch a power relay such as a Honeywell RA89A (or other). Unfortunately the kick-space thermostats are typically available only in 110ºF (Low Option) 0r 130°F (Standard). However they can also be directly wired into an HVAC System, depending upon type. Commercial variants are available in different temperature settings as may be required.

    Using the prior technique another expedient is available. Purchase a common 24/7 Day Cycle Timer to dry switch the Honeywell RA89A Power Relay directly via its T-T (Thermostat) Terminals. Program the timer to approximate the 24/7 occupancy periods. Not as efficient, since intermediate heating cycles are not accommodated, but comfortable for the congregation. 

    Air lamination is an atmospheric attribute that must be addressed in all heating and cooling applications. Our scenarios apply not only to churches but assembly halls, public buildings and selective residential applications. In the end it’s cooperating with Mother Nature rather than fighting her.

     


  • SUBMISSION FOR NON-PROVISIONAL (UTILITY) PATENT PROTECTION

    BoilersOnDemand.com via its Principal, Paul D, Mercier, Sr., has filed for Non-Provisional Intelligent Property Protection (Utility Patent) in the United States of America and Canada on the: ENHANCED CONVECTION, DIFFERENTIAL TEMPERATURE MANAGED, HYDRONIC HEATING APPLIANCE.

    We deem this to be the first, truly integrated, free-standing, simple, durable Hydronic (FHW) Heating Appliance in the Market. Enabled by recent advances in Delta-T ECM Hydronic Distribution, the major elements of energy generation and distribution augmented by our optimization of natural convection (Gravity Heating) comprise the highest efficiency product available ….. bar none!

    A true “appliance”, merely coupling it to site utilities and radiation effects a completed hydronic (FHW) heating installation. Dramatic reductions in materials, labor & skill content, floor-space and maintenance have been realized. A truly “Value Engineered” product.

    Further detail will be made available on our web site www.BoilersOnDemand.com as we finalize our patenting process.


  • DELTA-T ECM HYDRONICS – Redefining “The Plumber’s Playground”

    Hydronic heating comprises warming water as a medium, moving and expending its energy to warm an environment. Thus we have boilers as heat generators and radiation to convert heated water into warmth. Between these we must distribute our medium via pipes, pumps, valves and controls to meet heating demands.

    Basic hydronic system design rules of course must apply, but by and large the final product interpretation has been left to the tradesman/installer. This individualization provides a very attractive latitude of self-expression. Like an artist painting on a new canvas individual skills, styling and practice all comprise the final “picture”, with the author’s “signature” applied. Based upon our field observations we have come to refer to hydronic distribution in particular as “The Plumber’s Playground”, and with no apologies offered.

    Unfortunately the Laws of Physics apply equally to hydronic system installations as to any other enterprise. Therefore that maze of pipes, valves, circulators, controls and wiring evidenced in a “plumbers playground”, no matter how pretty, daunting or impressive is unnecessarily complex, costly and under-performs. In fact any system installed within the past three years or more not employing Delta-T ECM Hydronic Distribution Technology specifically is woefully under-performing!

    The Heating Game has changed, led by the Taco® Delta-T ECM VT2218 Hydronic Circulator and its supporting Taco® Zone Sentry Valves. We refer to it as “The Hydronic Revolution”, as it truly is! These two (2) devices, properly applied, can and do dramatically simplify the complexity and content of a conventional hydronic heating system. Again, properly applied and supported by contemporary control systems provided by an “Intelligent” System Aquastat with idealized piping (plumbing) can further enhance performance, as our work has evidenced. Our development efforts and observations are reflected within the remainder of this presentation.

    The Delta-T ECM Variable Speed, Intelligent, Multi-Temperature-Sensing Circulator is a marvel of applied technology. Its ability to sense, measure and maintain a preset temperature differential in a hydronic circuit virtually optimizes heat transfer efficiency in a single, automatic step. Further being able to accommodate varying demands from multiple zones (circuits) virtually seamlessly as we have evidenced places it as the heart of any hydronic system. Using an automotive analogy we slogan that we are putting an ‘Automatic Transmission’ on a Boiler, but doing it hydronically.

    Now pair this Taco® Delta-T ECM Circulator with a compliment of their Zone Sentry® Zone Valves and you dramatically reduce energy consumption while gaining some further fuel efficiency. As Taco® promotes we are seeing distribution power consumption drops to 11-13 watts and in another instance to 8 watts during normal operation! Compare these with 80 watts for a single Taco® 007 and 21 watts each  for a Heat Motor Zone Valve. (The Zone Sentry® uses 11 watts, and then only in a brief actuator “charging cycle”.) Hydronic heating system power consumption is virtually never considered in design, but it should and furthermore must be!

    Piping is the pride of any plumber (ourselves included) yet in so being can become a detriment to system performance. To this point we offer that hydronic convection (the natural attribute of heated water to rise, and cooler fall) is not considered as a positive contribution to system performance, but an attribute to be controlled. As we have witnessed in our design effort however, natural convection is a measurable asset, particularly when configuring piping and placement to maximize its effect. Near-boiler piping, to employ the trade term, is crucial to maximizing hydronic performance. Compacted packaging of correct pipe sizing and layout close to the boiler displays great natural (non-powered) circulation that may not only supplement but also heat at reduced levels. We had an early Delta-T Circulator failure on one of our “beta” installations that was not discovered for an estimated 2-3 days! How’s that for convection — like “paddling your canoe with the current”.

    When you fully integrate the “intelligent” Delta-T ECM Circulator, Zone Valves and Aquastat with idealized convection you come to the conclusion that hydronic system installation is no longer a process, but functionally becomes an Appliance. Our resultant “package” is contained within its boiler footprint plus minimal rear piping space. A designer need only define system capacity, number of zones, fuel type and exhausting to define the “appliance”. Further, the application lends itself to modularization, and thus to versatility by default. Not only do we significantly reduce the material content of a system, but its labor content and installation time as well.

    Now there is both a trade and consumer option, a virtual Hydronic Heating Appliance with a fixed cost and defined, superlative performance. Our work to date has been developing a “Package Delta-T ECM Hydronic (Oil) Heating System” that achieves its higher performance by incorporating Delta-T ECM Hydronic Distribution Technology with a high-mass, lower operating temperature boiler for optimized performance. But also recognize that Delta-T ECM Circulation will work on any fueled hydronic application, putting an “automatic transmission” on ANY boiler. This obviously reduces the size, content and complexity of the “Plumber’s Playground”, but to a net performance advantage in doing so.

    To summarize, a “Hydronic Heating Appliance” is in our near future, defined by technology and necessitated by the market, like it or not. Its Performance Specification will virtually determine system performance, unlike the potpourri of present practice. Our publicized contributions are documented on our website www.BoilersOnDemand.com.  Please note that our current and following product offerings are under Intelligent Property Protection (Patent Pending). We look forward to “Boilers On Demand” in the new “Plumber’s Playground”.


  • “DELTA-T (ΔT) ECM HYDRONIC HEATING 101” PRESENTATION AVAILABLE

    We have formulated and make available a Power Point Presentation entitled “DELTA-T (ΔT) ECM HYDRONIC HEATING 101”.

    It details our development and application of the Taco® VT2218 Circulator as a Dedicated System Circulator creating a “Packaged Delta-T ECM Hydronic (FHW) Heating System” (Patent Pending).

    Contact us for additional details and arrangements.

    603-588-2333 or info@boilersondemand.com

     


  • Oil & Natural Gas as Heating Fuels Equate @ $45/bbl

    By our calculation #2 Heating Oil and Natural Gas equate at an approximate Crude Oil Price per Barrel of $45 in our locale (Northern New England). There are obviously many factors that contribute and must be individually qualified.

    Refer to our prior posting on “The Heating Blog” entitled“Oil Again The Cheap Heat ………….. “for procedural detail. Note that it was published with Oil @ $30/bbl this past January.

    Of particular note is to always delineate between a “Delivered” vs. a “Distributed” Fuel. Whereas you purchase a quantity of fuel upon delivery (Oil, Propane, Wood, Coal, etc.), Natural Gas & Electricity are piped/wired to your location and you necessarily pay “service charges” for their facilities usage, maintenance, profit, etc. Factoring your “distributed fuel” bill is simple. Extract the actual cost for “fuel” and divide it into your total bill. The resulting “factor” of 1.XX must be used to multiply any stated “distributed fuel” cost for an actual one. Note that this “factor” is always changing and is particularly dramatic when comparing mid-summer and mid winter fuel costs.

    You will note that the only two viable heating fuels at present are Natural Gas and #2 Heating Oil. Even our regional “Fuels of Opportunity” as we refer, Cord Wood & Wood Pellets, as purchased are far less economic than generally perceived. Even “free” (self sourced and provided) Cord Wood is arguably uneconomic in use, particularly in our experience when purchasing and servicing Exterior Wood Boilers, a regional fad.

    To achieve an “apples to apples” heating fuel comparison you must use a contemporary appliance cost and performance for the fuels being considered. We use a 95% AFUE average value for Natural Gas & LP (Propane) Appliances and an 87% AFUE for Heating Oil. The Oil vs. Gas Heating Appliance Cost must also  always be considered in calculation, the Gas Appliances being pricier than their Oil equivalents.

    The further unwritten and unstated longevity of Gas vs. Oil Installed Systems must be quantified. You are not going to obtain system life expectancy from your “salesman”, who at best quotes Warranties (if you insist) nor provides maintenance histories. These come from the “old sergeants in the trenches” ….. independent service personnel who daily deal with prior work. Unfortunately they are too few, their voices are seldom heard nor are generally known, overshadowed by the self-anointed trade professionals and marketeers. We talk to the Sergeants …..

    Please avail yourselves of our extensive “The Heating Blog” Library on our website for further detail to your particular situation.


  • THE DELTA-T ECM CIRCULATOR — The “Automatic Transmission” for Boilers

    After speaking on-site  with a local customer about his system, he inquired as to what else we were doing. A mistake on his part.

    Both of us having differing technical backgrounds I launched into an inspired dissertation of our application of Delta-T ECM Circulation to Residential FHW Heating Systems. Obviously very interested, a running Q & A exchange of increasing technical depth ensued to the point of my noting he was developing that “deer in the headlights” look of incomplete understanding.

    We engineering types have a terrible habit of technically overloading our audiences, not as an “ego-trip”, but to inform as effectively as possible — we think!

    Needing to salvage the situation I paused, desperately searching for that inspired “bolt of lightening” to strike and clarify the atmosphere. By seeming grace, it came immediately! “I’m putting Automatic Transmissions on Boilers.” Yeah”, he responded, “that makes complete sense. Good idea!” Our further conversation became an analogy of FHW Heating Systems to Automobiles, surprisingly clearing our technical disparages. To expound …..

    After all, hot water boilers and automobile engines are both truly “heat engines”. An automobile engine must convert as much fuel combustion energy into mechanical propulsion power as possible via pistons, crankshafts, etc. Less than 60% becomes useful power, the remainder is dissipated as waste heat. The hot water boiler on the other hand necessarily converts its fuel combustion energy directly into useful heat at up to 97% efficiency!

    The automobile uses a transmission to adapt its mechanical power to control vehicle propulsion. A variety of gears, pumps, valves, etc. are used to accomplish this. The hot water boiler conversely needs only to move heated water (via a pump) exactingly to ideally acclimate our heated areas and (optionally) our domestic hot water (DHW).

    The Delta-T ECM (Differential Temperature) Variable Speed Circulator (Pump) is that ideal “boiler transmission” that delivers heated water most efficiently to maintain our comfort. So efficiently does it do so as to reduce system fuel consumption by up to 15% and electrical consumption by up to 85% as documented by Taco, Inc. Published Testing Results.

    No longer is heating system efficiency measured solely (and inaccurately) by the Boiler AFUE (Annual Fuel Utilization Efficiency) Rating, but the aggregate of Boiler, Distribution and Radiation Efficiencies. There are THREE (3) Elements in a hydronic heating system! Just as in Sulky Racing, it’s the combination of the horse, the jockey and the buggy that wins races.

    Even more exciting  is the opportunity provided by the Delta-T ECM Circulator to most efficiently configure a FHW Heating System, which we have done very effectively. Refer to our other, recently published Delta-T Blogs on this site that detail our development, field testing and observations of our systems.

    Our “Packaged Delta-T ECM Hydronic Heating Appliance™” (Patents Pending)exhibits the following attributes in direct comparison to the typical “conventionally installed” system:

    1. Has a higher Combined Boiler AFUE and Delta-T ECM Distribution (System) Efficiency than achievable with any “conventional” system configuration.
    2. Consumes less fuel and electrical power than any equivalently sized system.
    3. Our Integrated Boiler/Indirect Water Heater System occupies 1/3 to 1/2 the floor-space of others.
    4. Our proprietary Fully-Iron & Cast near-boiler piping maximizes durability and distribution performance using fewer materials.
    5. Further combining a High-Mass Boiler with an All-Stainless Indirect Water Heater assures a dramatically projected economic life (30 years or more?).
    6. A true universal, multi-fuel Appliance. Just change the burner —– not the system!
    7. Provides, Simple, Durable, Efficient and Cost-Effective FHW Heating.

    So yes, we do put “Automatic Transmissions” on Boilers!

    Author’s Note: Updated 07/23/2018


  • BEYOND AFUE’S – TOWARD REAL HYDRONIC (FHW) HEATING EFFICIENCY!

    For the past year Mercier Engineering has been immersed in developing and preparing for market it’s Packaged Delta-T Hydronic (FHW) Heating System™, based on our past heating experience projected into the new world of “Delta-T Circulation”. You may have noted our preoccupation with this technology in “The Heating Blog” on our www.boilersondemand.com  website. Time to “put our money where our mouth is”, so to speak. The results of our efforts we deem noteworthy and are initially reflected in this writing.

    As the titling of this blog purposely implies, we must get beyond weighing hydronic heating system efficiencies solely upon the boiler’s Annual Fuel Utilization Efficiency (AFUE) Rating.  It is only one of multiple elements in an operational formulation that is seldom if ever approached, even more poorly understood, and we allege almost universally misapplied. Strong words which must be tempered by the reality that there has been little market incentive to change our approach to serving the residential FHW heating market in particular; but we ultimately must adapt and change it for the consumer’s benefit.

    AFUE is a regulatory, laboratory testing procedure intended to establish an efficiency value for a hydronic (hot water generating) boiler under a defined operating sequence and conditions. It can be presumed that it executes this comparison very effectively, under its terms. However, what it does not measure from our observations is in practice very significant. Specifically these Non-AFUE Test Attributes are:

    1. There are no provisions for qualifying or measuring between-cycle “stand-by” or “idle-time” losses. This is the time between burner firing cycles when the boiler is prone to radiated energy and convective exhaust (flue) losses, presumed to be non-productive.
    2. Similarly, the testing is “steady-state” in execution, providing no qualification or quantification of individual boiler attributes that may contribute to site application efficiency.

    These test attribute observations have been borne out in field applications, where system performances have not correlated well, boiler-to-boiler or system-to-system. To further complicate this is the variability of physicals to each application, however subtle. The forums and blog sites are rife with these seemingly “apples-to-oranges” commentaries. Our developmental efforts may be able to provide some explanations.

    From our observations there are necessarily five (5) elements contributing to total system energy efficiency:

    1. The boiler (heat engine) energy conversion efficiency or AFUE.
    2. The physical attributes of the specific boiler complimentary to system operation.
    3. The energy required to move heated water through the distribution system (radiation).
    4. The effective matching of radiation elements to heating demand.
    5. The control algorithm(s) to match energy creation with varying system demands.

    Our initial efforts have been with oil-fired hydronic systems and is the focus of this document, with gas-fired and solid-fuel applications to follow as resources permit. However, much of this effort is applicable as the basis of other heating systems.

    Varying the output (energy creation rate) of any heating resource is paramount. This has been readily achieved in gas-fired boilers by “modulating” combustion with sophisticated valving and controls. Typically they adjust from 20 to 100% of capacity, from “idle” to “full speed” to use the automotive analogy. However, direct modulation of oil-fired systems is not feasible using current technologies. A fixed (capacity) firing rate via pressurized, nozzle induced fuel atomization is the norm. Therefore, the only option is to adjust the operating temperature of an oil-fired hydronic boiler via controls to compliment heating demand. This is reasonably well-managed with modern “cold-start” aquastats, external temperature sensors, etc.

    The prior unaddressed penalty to particularly residential hydronic systems has been the toll on equipment and electrical energy requirements of circulating heating water with fixed-speed circulators. They are notoriously and arguably universally misapplied and inefficient in practice. Reducing water temperatures merely aggravates the situation by prolonging circulator cycling.

    Fortunately technology has come to the rescue in the form of the “Delta-T” Circulator, now becoming very applicable and affordable to the residential/light commercial markets. The undisputed pioneer and flag-bearer in this market is the Taco Viridian VT2218 found at this link: http://flopro.taco-hvac.com/media/Viridian_VT2218_100-114.pdf  To use the quote “This changes everything” is not an exaggeration! The Viridian is in fact the second generation, replacing the entry product Taco “BumbleBee” found at this link: http://www.taco-hvac.com/uploads/FileLibrary/100-101.pdf We mention the “BumbleBee” only because it has rapidly become a “cult product” in the HVAC Community, somewhat akin to the “Trekkies”. It was our initial “new tool” in developing and thence refining our product(s). Like our brothers, we hate to see it go as we move to the refined and more sophisticated “Viridian”.

    Referring back to our five (5) elements to total system efficiency, Delta-T Circulation is number three (3) on the list but is deservedly and necessarily the foundation of any hydronic system improvement. Taco reports system Delta-T Circulator-only swaps yielding 15% fuel usage reductions. It is the keystone of our Packaged Delta-T Hydronic (FHW) Heating System™, and should be the first improvement to any system! We caution however that this will require substantial near-boiler system re-piping and your installer must be knowledgeable. It is discouraging to note how few of our fellow tradesmen are cognizant of Delta-T or have used it beyond a radiant heat loop. We “Old Dogs must learn new tricks”, and we have!

    The second element of import is the necessity to employ “Cold-Start” Boiler/Aquastat Hydronic Technology, which overlaps Nos. 2 and 5 in our list. We are unabashed in our praise of the Hydrolevel 3250-Plus “Fuel Smart” Aquastat, found at this link: http://www.hydrolevel.com/new/images/literature/sales_sheets/fuel_smart_hydrostat_sales_sheet.pdf   It is now standard equipment on all our Weil-McLain Ultra Oil Boilers, and none too soon! The inter-action of the 3250-Plus with the VT2218 Circulator’s operational software is paramount to total system performance, as we have learned.

    Note: “Cold-Start” Technology applies to “heat-only” boilers. DHW (Domestic Hot Water) must be effected by an external Indirect Water Heater or another dedicated appliance. We combine the Indirect Water Heater in our design for optimized Heat and DHW Generation.

    Element 3: Our development indicates individual boiler attributes are significant. Specifically,

    1. Boiler supply and return tap placements are crucial to system “packaging”, i.e. the ability to compactly (efficiently) structure near-boiler piping. (We can pipe into a space as close as 11″ from the chimney, with all piping and controls behind the boiler, yet readily accessible.)
    2. A very high boiler mass (weight) for its capacity, i.e. for both thermal damping and storage.
    3. Favorable exchanger flue passage routing and exhausting.
    4. Burner type to compliment its attributes.

    The noted attributes lead us to our “Boiler-of-Choice”, the Weil-McLain Ultra Oil Series with the Beckett NX Burner. Refer to this link for detail: http://www.weil-mclain.com/en/assets/pdf/Ultra%20Oil%20Brochure_8%20Pg_web1.pdf   We have had “conventional” system design and installation experience with this boiler for over ten years now, with only one “no heat” service call, a failed aquastat. Weil-McLain has since upgraded it to the Hydrolevel 3250-Plus, thank God!

    The Beckett NX Burner has been likewise flawless in operation. Literally a “plug and play”. Its dual vent typing capability (direct & chimney) has proven beneficial to problematic venting applications, especially when encountering “cold chimneys” in our northern climate. Fully exposed exterior chimneys are sure to give a rough startup without utilizing its pre-purging and pressure firing features.

    The key attribute to system performance outside of Delta-T Distribution has proven to be Thermal Mass (Storage) provided by the sheer robustness (weight) of the Weil-McLain UO Series High-Mass, Triple-Pass Boilers. They are “The Heavyweight Champions” by far and as a result exhibit lower mean boiler operating temperatures and very less frequent burner cycling.

    As a matter of policy we do not cite or criticize our competitors, but we must make a single attribute comparison to emphasize our point. The approximate block weights of the top hydronic (approx. 100KBTUH, 87% AFUE) oil boilers are:

    Manufacturer/ModelApprox. Ship Wt.
    less Tare (lbs.)
    % of HighestComments
    Buderus G115/G21537560%Adjusted for 100KBTUH
    Burnham MPO-IQ11545072%
    Weil-McLain UO-3625100%

    AUTHOR NOTE: Very noteworthy, the Weil-McLain UO is also disproportionately the lowest cost per pound (by nearly half) of the three. Just what is the consumer paying for, we wonder? In our development experience increased boiler mass equates to improved system longevity and hydronic performance!

    Radiation (Element 4) efficiency is the remaining, but least controllable variable in a heating system. It is substantially outside the scope of our system application, yet there are some performance elements we can address.

    Existing hydronic radiation:

    1. Removal of unnecessary valving in zone supplies and returns. All zone supply functions are integrated into our system package.
    2. Zone interconnection and functionality can be optimized by correct pipe sizing and routing. It confounds us as to why some plumbers use virtually no 45° fittings! You can use 3-4 of them vs. a 90° elbow for the same flow resistance, and only 70% of the pipe required for a 90° elbow routing.

    New hydronic radiation:

    The contemporary approach to radiation varies widely, from simple radiation loop(s) for zoned heated areas to individually heated rooms throughout. The more finite the control, the more piping, fittings and control valving, the more hydronic distribution energy is required.

    Ironically, the same Delta-T Circulator Technology we employ to maximize our system performance has preceded us and become the darling in particularly radiant system applications. We have also employed them in these and they perform admirably. They reduce the energy requirements significantly but yet still camouflage that basic issue.

    If your concern is total energy consumption of a system, we would invite you to consider using less sophisticated radiation distribution schemes. A properly designed, installed and balanced series or split piping loop exudes simplicity and will likely be a lower installed cost. The KISS Principle applies — keep it simple ….. (Refer to our Heating Blog Library for additional detail.)

    To Summarize:

    1. Additional Boiler Attributes are important, beyond the AFUE Rating. In particular heat exchanger thermal mass (weight) will lengthen service life while minimizing repair costs. Burner attributes related to exhausting and tuning must also be considered.
    2. Delta-T ECM Hydronic Distribution Technology is key to improving any system’s energy performance, both heating fuel and electrical power consumption.
    3. Inter-related “intelligent” controls determine system operational performance. They are currently the Hydrolevel 3250-Plus Boiler Aquastat and the Taco VT2218 Delta-T Circulator Logic.
    4. Near-boiler plumbing in particular affects system performance. This is optimized in our system piping configuration to include fail-safe “natural gravity convection”.
    5. Interconnections between our system zone access points to existing radiation must be executed with the goal of minimizing flow anomalies.
    6. Existing and/or new radiation installations must likewise be executed by idealizing flow conditions inasmuch as possible.

    References:
    We strongly recommend referring to Taco’s website link http://flopro.taco-hvac.com/deltat_resources.html and refer to the various Delta-T resources therein. There’s a volume of resources here that will properly inform you of this new technology and its place in your Hydronic (FHW) Heating System.

    Author’s Note: Hyperlinks updated 08/27/2019


  • WHAT IS A DELTA-T SYSTEM?

    A Forced Hot Water (FHW) Heating System is designed to efficiently provide energy distribution to heated areas. This is accomplished by combusting fuel in a boiler and moving the heated water through radiation to warm the desired environment.

    However, to accomplish this most efficiently requires:

    1. A high-efficiency appropriately sized and fired boiler.
    2. Properly proportioned and positioned radiation for each heated area.
    3. Idealized, simultaneous energy delivery of heated water to all radiation, irrespective of heating demand patterns.

    Practically however, none of these elements are absolutely correct, nor can they be. Boilers and radiation are almost never idealized for efficiency, but the third (energy distribution) is typically the most poorly executed of all. You must deliver heated water at an ideal rate for maximum heating transfer efficiency.

    Common distribution systems typically consist of:

    1. Dedicated circulators for each zone, or
    2. A common circulator with a zone valve for each zone.

    These configurations do not perform efficiently in practice, and in particular zone valves.

    “Delta-T” is a technical connotation. “Delta” (from the Greek letter ∆) is difference, or differential. “T” designates temperature. Thus Delta-T (∆T) is “differential temperature”.

    The Delta-T Continuously Variable Speed Circulator  employs temperature sensors attached to the boiler supply and returns points. It measures and maintains the ideal temperature differential by infinitely adjusting its water delivery rate (pump speed) to suit. Coupling with the new Low Energy, High Flow Zone Valves this technology maximizes the efficiency of any hydronic system with dramatically reduced electrical power consumption.

    VT2218+ZV

    Additionally, this system also smooths the performance of your existing radiation by typically eliminating hydronic whistle from over-sped, heating lag and imbalance from under-sped zones.

    No costly control system is necessary! The innate intelligence of the Delta-T Circulator teamed with the self-diagnostic capability of this new generation “Green” Zone Valve simplifies wiring, installation and diagnosis.

    It’s a Terrible System. Terribly Simple – Terribly Efficient!


  • 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?