Share Facebook Twitter Google + LinkedIn Pinterest By Dan Armitage, host of Buckeye Sportsman, Ohio’s longest running outdoor radio showIn 2015 Ohio’s lawmakers passed a bill that prohibits dredged materials from Lake Erie harbors or any other navigation maintenance activities to be deposited into the lake after June, 30, 2020. Called “open lake dumping,” that’s been the acceptable disposal method for uncontaminated siltation and other dredgings. With a five-year compliance window about to close, that option is about to change.The impact of the new dredging regs will be greatest on the eight commercial ports along Ohio’s Lake Erie shorelines, where the US Army Corps of Engineers is responsible for the harbors that require regular dredging to maintain commercial traffic and recreational boaters and anglers enjoy the benefits. However, most of Ohio’s private and public small boat harbors and marinas along Lake Erie also require periodic dredging. As with the Corp’s commercial operations, those dredged materials have always been allowed to be put back in Lake Erie. But beginning 2020, those materials must be contained on an adjacent land site or trucked out to an upland containment area, increasing dramatically the dredging costs for marinas large and small.On the up-side, some of the commercial harbors are looking at the feasibility of a dredge-to-soil project, placing the material on an area that allows it to drain, after which it would be removed, blended and offered for sale as topsoil. Other options include the creation of a nearby “marsh land” which could become habitat for plants, animals and birds.So, if you witness lots of dredging activity in your favorite Lake Erie marina this season, and an increase in launch and dockages fees to follow, you’ll know why. Free boating training offeredSpeaking of boating, the United States Power Squadrons, now known as “America’s Boating Club,” has been promoting and educating safe boating for more than a century. The Columbus Sail and Power Squadron unit has a memorial educational fund established by one of its members to cover the costs of the upcoming class to earn the Ohio Boat Operators license, required of boaters born in 1982 or later who operate a boat with a motor of 10 hp or greater. Sign up is first come-first served at the web site for the 8-hour training program that will be held from 8 a.m. to 5 p.m. on Saturday, Feb. 23 at the organization’s north Columbus facility. Students will learn everything needed to safely operate a power boat and will be tested on their knowledge at the end of the day to earn the Ohio Boat Operator License. Ohio Department of Natural Resources Watercraft officer will provide training for State of Ohio requirements, and topics include safety equipment, navigation rules and aids, finding your way, lines and knots for every-day boating, trailering, anchoring, communications afloat, lights and sound signals. For more information and to register for the free class, visit: cspsboater.orgFree frigid digit fishing instructionA free ice fishing clinic will be offered by the ODNR on Saturday, Feb. 16, from 9 a.m. to 2 p.m. at the Hebron State Fish Hatchery, 10517 Canal Rd, in Hebron. Experts from the Ohio Division of Wildlife will discuss topics such as ice fishing planning and preparation, equipment use, and safety. Demonstrations and hands-on fishing opportunities in the field are planned, conditions permitting. Some equipment is available for use, but participants are encouraged to bring their own ice fishing gear. A fishing license will be required for participants 16 years of age and older and licenses must be obtained prior to the event. Participants are encouraged to dress appropriately for the weather as portions of this workshop will be held entirely outdoors.The workshop is free but pre-registration is required as space is limited. Call 614-644-3925 or email [email protected] to register. You must provide your customer I.D. number found on your fishing license when registering for this clinic. To read more about ice fishing in Ohio, visit wildohio.gov. Wecker named Chief of Wildlife DivisionODNR Director Mary Mertz has selected Kendra Wecker as Chief of the ODNR’s Division of Wildlife. Wecker has more than 25 years of experience working for the division building programs and partnerships that have helped shape Ohio’s conservation efforts. She becomes the first female Chief of the Division of Wildlife and began her assignment on Jan. 20.Wecker has advised numerous ODNR Division of Wildlife chiefs and other senior staff on legislative issues for all aspects of hunting, fishing, trapping and shooting sports. She has worked on many large projects affecting Ohioans, including commercial fishing regulations, Sunday hunting and improved shooting ranges.As chief of the division, Wecker will be responsible for day-to-day operations, including issues related to wildlife law enforcement, fish and wildlife research and management, promoting and establishing regulations related to wildlife recreation including hunting, fishing, trapping and wildlife watching, as well as the responsible management and investment of funds generated from the sale of hunting and fishing licenses and related equipment.Wecker was the wildlife diversity coordinator for almost 20 years before becoming the information and education executive administrator in 2016. In both roles she worked with outside organizations on outdoor public education programs, advised multiple chiefs on important topics, managed research project budgets totaling over $1 million, and coordinated legislative issues for the division. During her tenure she has been the recipient of multiple awards, including Wildlife Conservationist of the Year from the League of Ohio Sportsmen. According to the state agency, the Ohio State University graduate enjoys camping, fishing, and hunting with her family.Former Division of Wildlife Chief Mike Miller will stay within ODNR as acting law enforcement administrator for Parks and Watercraft. Miller served the ODNR Division of Wildlife for a year and a half, helping to bolster law enforcement capabilities and create the multi-year and lifetime licenses for hunting and fishing. New Wildlife Chief Names New AssistantsNew Division of Wildlife Chief Kendra Wecker recently announced the appointments of Pete Novotny and Todd Haines as assistant chiefs for the division. Together, Novotny and Haines bring more than 50 years of experience working for the division to their respective positions.Novotny began his career with the ODNR Division of Wildlife in 1996 as a wildlife officer, serving Harrison County. He continued working in the division’s law enforcement section until 2015, when he was promoted to manager of the division’s District Three office located in Akron where he led a staff of biologists, wildlife officers, public outreach and business personnel. Since April 2018, he has served as acting assistant chief and administrator of the division’s law enforcement section, overseeing all fisheries, wildlife, law enforcement and district operations. Novotny received a Bachelor of Arts degree in biology from Wittenberg University in Springfield. He resides in Cadiz with his wife and two sons.Haines began his career with the ODNR Division of Wildlife in 1987, working as a wildlife research technician in Oak Harbor. In 1993, he moved to southwest Ohio, working as a management supervisor in the division’s District Five office located in Xenia. Since 2003, Haines has served as the manager of the District Five office, leading local staff, building support with constituents, and supporting hunting and fishing opportunities for the public. Haines received a Bachelor of Science degree in wildlife management from West Virginia University in Morgantown, West Virginia. He resides in Wilmington with his wife, and they have two sons.
Stuff I Learned at Joe Lstiburek’s House, Part 1Duct Leakage TestingStatic pressure and flow are directly related to the electrical power required at the fan, which uses 80% of its energy to overcome static pressure and only 20% to create air velocity. This is why the SEER ratings of ductless minisplit equipment are much better than of the exact same model with ducted /cassette options. Ducts matter.The numbers here are infinitesimal – 0.011 PSIStatic dressure drop is commonly stated in terms of “inches of water column” (abbreviated “inAq” or “inH20”) or pounds per square inch (PSI). 1 PSI = 27.68 inH2O = 2.3 feet of head = 0.68 atmosphere = 6895 pascal (newtons per square meter).Pressure drop created by fittings in a length of duct is expressed as “equivalent duct length” — that is, the length of straight duct of the same cross sectional area that would create the same static pressure drop as the fitting in question.Air handlers are typically designed to operate against a static pressure of 0.3 inH20 or roughly 75 pascals or 0.011 PSI. The numbers here are infinitesimal compared to the 18 feet of head = 7.8 PSI numbers I’m used to dealing with in plumbing design.It’s important to understand static pressure because a 2½-ton (30,000 BTUh) heat pump needs to move 960 cfm to transfer that heat at a 30 degree temperature rise, but if the static pressure is too high, air flow will be reduced, limiting its ability to remove heat from the coil and transfer it to the home.As many as 80% of ECM motors use more power than the PSC motors they replacedA typical 1/3 hp PSC motor is designed to move 1,000 cfm at .30 inH2O while drawing 335 watts. At a higher static pressure of 0.6 inH2O, the same motor will deliver only 400 cfm, but will only draw 240 watts doing so, as the blower wheel blades simply recirculate an increasingly large percentage of their air, doing less work and thus drawing less power. A similar unit with an ECM blower can deliver 1,000 cfm at 0.3 inH20, drawing 225 watts; the ECM motor will still deliver 1,000 cfm at a higher static pressure of 0.6 inH20, but will draw 350 watts to do so. In other words, at a higher static pressure, the ECM motor continues to deliver 1,000 cfm (unlike the PSC motor, which delivers less air as the filters clog up). Gavin Healy commented that he has seen 4-ton and 5-ton gas furnaces with ECM blowers that were drawing 900 to 1,200 watts.David Hill believes that as many as 80% of energy-efficient ECM motors in HVAC systems actually consume more power than the PSC motors they replaced (but they do a better job of delivering the air across the coil and to the house).If the blower is only delivering 400 cfm due to that 0.6 inH2O static pressure, the ability to move heat is cut 60%, and that excess heat builds up in the cabinet and gets returned by the refrigerant to the compressor. The compromised equipment runs at high temperature/refrigerant pressure, returning more heat to the outdoor compressor. It runs longer and harder, with greatly reduced efficiency, both because it’s trying to heat refrigerant that is already hot and because the heat isn’t getting to the home to satisfy the thermostat.The “ductulator” only addresses 10% of duct lossesToo much attention in duct design gets focused on pressure losses due to duct friction. Part of the reason for this is that architects don’t give the HVAC crew enough room to take advantage of opportunities for better trunk line fittings and cabinet optimization, so duct length and sizing end up being the only variables they have control over.While flex duct that is pulled tight and well supported has less loss than slack or poorly supported flex, the friction component calculated using a ductulator (duct calculator) is not the primary villain here, at only 10% of losses. “System effects” of the furnace or air-handler cabinet, as well as coil and filter losses adjacent to the blower inlet and discharge, are second in importance at 30%. Duct fittings represent 60% of losses, and are therefore far more significant in actual practice.Evase opportunity and squirrel cage AikidoThe first opportunity for improvement is to give the air handler room to breathe on both the return and supply side of the cabinet. An “evase,” a piece of duct that increases in size and may change from rectangular to round in cross-section as it moves away from the air handler, helps bring the air out of the air handler in the same way that loud “megaphone pipes” on a motorcycle help pull exhaust from the manifold.When we look at how air escapes from a centrifugal (squirrel-cage) blower, we discover that it is moving at a different velocity depending on where in the exit cross-section it’s located. If we can give it three times the duct diameter to come to equilibrium before asking it to change direction, more of the energy in the fast air stream will be imparted to the slower air around the edges and close to the throat, and less will be lost to system effects.When choosing a cabinet for best air flow characteristics, we will be better served by equipment that pulls the air through the coil and exits through the blower rather than entering the cabinet through the blower and exiting through the coil.Don’t hit filters at an angle or with turbulent flowSimilarly, when we look at the static pressure impact of the filter, we discover that it is very much in our interest to hit the filter square on with the air stream rather than putting it in the wildly disturbed flow at the outlet of an elbow or angled to the stream as often happens when it’s on the intake of the air handler.The difference of the pressure curves of clean versus dirty filters is pretty shocking as well. In one example, an ECM system with a clean filter running at 0.2 inH20 at 1,100 CFM drawing 225 watts ran with a dirty filter at 0.5 inH20 at 1,100 cfm drawing 320 watts. If it had been a PSC motor on that air handler, the flow would have been reduced on the order of 40-50%.My takeaway here is that in homes with 100% of return air duct inside the conditioned envelope, it may be a good idea to install multiple air filters in the grilles where they have uniform face velocity across the full area of the filter and are readily accessible for service rather than in the mechanical room.Mind your elbows and wyes, especially in the trunk lineThe biggest thing we can do is look more carefully at elbows and take-offs in the trunk. When air exits a trunk at a right-angle fitting, the shape of the heel of the fitting is much less important than the shape of the throat. According to the ASHRAE Duct Fitting Database, an 8×14 elbow with a square heel and a square throat at 500 fpm air velocity has a pipe length equivalent of 39 feet. If you radius the heel, the equivalent drops to 36 feet. But if we leave the heel square and radius the throat, the equivalent length drops to 13 feet!What’s happening here? When the air passes that sharp throat, it creates an eddy — a pocket of turbulence just downstream from the throat (similar to the eddy you rest in while white water kayaking). Unfortunately, this eddy has the effect of reducing the usable pipe diameter and restricting flow. (In hot water distribution, this same eddy in the pipe mixes cold and hot together, increasing the amount of time it takes the hot water to push the cold out of the way and get to the fixture.) The square heel also gets clogged with turbulence, but in this case it converts it to a radiused heel with a bit more drag and doesn’t restrict cross-sectional area.My great-grandfather told me soThe way that elbows reduce flow in HVAC systems is similar to how they increase delivery times in hot-water distribution systems.This gives me an opportunity to share some images from my great-grandfather’s book, Experiments Upon the Flow of Water in Pipes and Pipe Fittings made in Nashua, NH 1892, in which he demonstrates experimentally that “for commercial elbows … little would be gained by making the radius of curvature more than about three times the corresponding pipe diameter.”Got “turning vanes”?That first elbow with a square throat and heel but with turning vanes installed at 1 1/2” OC has an equivalent duct length of 4 feet! The vanes break the air flow down into 1 1/2 inch slices, and each slice is directed individually in a way that effectively minimizes the size of that eddy.Increasing the size of the vanes and spacing them further apart reduces the effective length even more, but increases the difficulty of production and the potential for error in placement and for restriction if a vane comes loose over time. Using an elbow with smooth heel and throat and three full length vanes can reduce the effective pipe length to one foot!Start with a third-party HVAC designer and give the tin-knockers room to practice their craftGetting your HVAC contractor to adopt these practices seems likely to create a different type of static pressure. I have a hard enough time just getting mine to implement curved fin ceiling registers with interior supplies. But I’ve had pretty good success with hiring a third-party engineer to do my Manual J, S, and D calculations and then including floor plans and sections of the mechanical room on the prints (a.k.a the “funny papers”).HVAC installers quickly realize that their liability for the performance of the system is favorably impacted by bringing in a third-party engineer to take responsibility for the calculations and duct design. If you don’t calculate and draw out what you hope to achieve, there will be no place to begin discussion or collaboration.Start with the mechanical room, the trunk, and the longest runs. Focus on minimizing fittings overall, and (at least) putting 45 degree gussets if not radius’s on the throats of your take-offs and elbows. Pull the filters away from the air handler to a place with clean, undisturbed parallel air flow where they can be easily inspected and serviced by the homeowners. Design-in room for an evase on the supply side of the air handler.The opportunity to recognize and correct pressure drop parasites in bad duct design is before they are covered in drywall. In the Southeast where I live and build, we mostly rely on ducted HVAC systems for heating and (especially) for cooling. So when I attended the Westford Building Science Symposium in early August, I was very excited to sit in on David Hill’s presentation on HVAC systems, especially as Dr. Joe’s introduction paraphrased Samuel Clemens’ observation: “It ain’t so much the things we don’t know that get us into trouble; it’s the things we know that just ain’t so.”I’m especially interested in situations where new research is disproving assumptions behind accepted best practices, since these re-evaluations lead the industry to fine-tuning and improvements. David Hill’s presentation on duct design was full of these. The “take-aways” I got from this are:to examine the way we do duct take-offs and fittings,to place an “evase” between the fan outlet and the trunk or the split for the zone valves leading to the trunk in a zoned systems,to look very carefully at filter placement and the taughtness of flex duct, andto start doing all this in the design phase so we allow enough room to implement thoughtful duct design before the sheetrocker removes the opportunity for improvement.Pressure drop parasites rob equipment of efficiency and durabilityDuct systems contribute to bad HVAC performance by increasing static pressure and reducing air flow through the air handler. Air is only capable of carrying 1,000 BTUh per 31 CFM at the 30 degree temperature rise typical of heat pumps. (A gas furnace will typically run with a 30-60 degree temperature rise.) A 2½-ton (30,000 BTUh) heat pump with a 30 degree rise will need to move 31 cfm/Kbtu x 30 KBTU = 960 CFM. RELATED ARTICLES