Power & Heat Systems, LLC frequently publishes case studies and technical white papers to display efficiency gained by using our represented manufacturers. Additionally, we like to stay at the forefront with technology updates within the industry and provide examples where their applications translate to monumental savings for our customers. Please check back frequently for new updates that will allow you to keep your boiler room operating at maximum efficiency for both time and money.
The Science of Boiler Efficiency
The advent of highly efficient and condensing hydronic hot water heating systems changed how engineers design and specify boiler equipment. To ensure that specifications comply with the best engineering practices, the science of efficiency and the flue gas water vapor dew point must be taken into account.
Digester Gas Applications
The application of sewer or digester gas as a special boiler fuel has been around for many years. Power & Heat Systems has been one of the leading suppliers of boiler-burners packages for this fuel. Any application of this waste gas must take into account special precautions because of the hydrogen sulfide (H2S) in this fuel.
Power & Heat can help you solve problems with many heat and control issues beyond the boiler room. A prime example is that of a large equipment manufacturer in Virginia that was suffering from a serious case of paint booth system downtime.
Their finished product required a very large paint booth that received all of its air from a Dravo make up air (MUA) unit. After many years of service, the system was showing its age with a dramatic drop in reliability leading to excessive downtime and high maintenance costs.
The paint booth is located in the center of a very large, high-ceiling, bay-type, manufacturing building, with the Dravo MUA unit located on the building roof directly above the paint booth.
The systems problems were the result of:
o Several obsolete controls;
o Several new controls that had not been properly integrated into the system;
o No central control panel to operate the system;
o Control stations where haphazard wiring had grown to resemble a rat's nest; and
o No literature or wiring diagrams for the system.
To make a bad situation worse, the primary system controls had been installed on the roof. Access to the system controls was only possible via a portable lift ride to the roof.
Repairs routinely required two and three trips to the roof, first to try and diagnose the problem, then after getting necessary parts to repair the problem, and too often to return and correct problems not diagnosed on the first trip. The production load at this plant was growing and now the paint system was becoming a choke point. This was unacceptable for a company known for delivering a high quality product with an on time delivery.
Power & Heat was called in to review the system and make recommendations. Our knowledge of the overall system and past experience with similar processes allowed us to win the redesign and rebuild contract. As is true with many projects, time was of the essence once the decision was made to move forward on the rebuild.
Power & Heat immediately started the redesign engineering portion of the project while we were also selecting the electrical contractor to handle the field rewiring required for the paint booth MUA system. Our customer had already developed a wish list for the operation of the rebuilt system:
o Move all controls to a new central control panel to be located on the production floor at the paint booth.
o Provide a single power disconnect to allow for easy and safe servicing of the system.
o Up grade the control system to meet all current NEC, UL, FM and CSD-1 safety requirements.
o Provide panel front indication that would allow their service technicians to handle future service with only one trip to the rooftop or any part of the system to solve a problem.
o Provide a more flexible and user-friendly panel front temperature control system.
o Add a humidity control system. High humidity levels on some summer days was limiting their ability to produce a high quality finished painted product. This too was adding to production delays caused by the paint booth system.
With the electrical contractor selected and the redesign engineering approved, a new challenge arose making the need for the repair all the more urgent. A surge in business was being threatened by the system problems. A compressed schedule for the field wiring necessary to accommodate the new equipment and system design changes was set with only three days at the end of that schedule for the paint booth down time for final conversion, start up, and operator training.
While the electrical contractor was roughing in the extensive new field wiring, Power & Heat was ordering the new control equipment and building the new control panel. During the final three days of the conversion Power & Heat technicians partnered with the electrical contractor for the installation of the new equipment, its wiring, and start up.
Professional project management ensured that the coordination of activities between Power & Heat and the electrical contractor was flawless. On the first day of downtime all the old controls were removed and some of the new wiring was connected. The second day saw the completion of the field wiring and installation of all the new equipment. Our final day, downtime involved checking motor rotations, starting the control system, and checking all safety items. By early afternoon of the final day the complete system was up and running, having passed all operating tests. Training of the customer's personnel was conducted and the reengineered
Paint Booth MUA system was returned to the customer's control.
The final project included the following:
o A new NEMA-12 control panel with 100 Amp disconnect located at the oven on the production floor;
o A Fireye burner management system with a Fireye first out annuciator and panel front display with simple English descriptions of any fault condition;
o A set of panel front lights (push to test type) to provide quick visual indication of operating conditions;
o A panel alarm bell with push button silence switch to warn of a system failure;
o Pull on and tap off start/stop buttons;
o New motor starters with built-in individual circuit breakers for full NEC compliance;
o Panel front main temperature control with digital display for:
o Actual make up air temperature
o Set point temperature
o Easy operator setting of desired temperature;
o Panel front humidity control with digital display for:
o Actual relative humidity level
o Set point relative humidity level
o Easy operator setting of desired relative humidity level.
The professionals at Power & Heat can partner with you to create/design/install innovative solutions for your complex challenges - in the boiler room and beyond.
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Energy costs continue to skyrocket across all business categories, taking a larger and larger share of company budgets. Because of this dramatic impact on company profits, every business should take advantage of any opportunity to reduce these costs. This is just as true for non-profit driven
entities as will as in as for profit driven companies. City and county wastewater treatment facilities are excellent examples of non-profit entities
which consume a lot of energy. These facilities need that energy to provide the heat to keep their anaerobic digester process working at peak efficiency to treat our wastewater.
One of the by-products of that digester process is a biogas, often called methane gas because it is approximately 50% by volume methane. This gas also contains a small amount of hydrogen sulfide (H2S) making it corrosive and lethal in low concentrations. But this biogas is an efficient fuel stock, with the significant cost benefit of being free.
Richmond, Virginia is very fortunate to be the home of one of the world's leading companies involved with water cleaning and purification. One of their groups designs and builds wastewater treatment plants used around the world. Power & Heat Systems, LLC, headquartered in the Richmond area, has been selected to work with the engineers at this company to provide the hot water boilers used to keep the anaerobic waste digesters working at peak efficiency. A recent project involved the installation of two boilers similar to the one shown in Figure 1. The package boiler shown was selected for this particular project because of its ability to solve many of the challenges associated with the efficient burning of biogas. For this particular project, several factors were considered during the selection process of this package boiler.
The high levels of maintenance repairs required to keep many systems working often have them out of service. The equipment selected for the boiler shown in Figure 1 has all been designed to efficiently burn the biogas and limit the need for the wastewater plant to use expensive natural gas, propane, or light oil to produce the hot water for the anaerobic process.
If the wastewater plant is not using the biogas as a fuel stock, it is required to flare or burn this gas to the atmosphere. The unburned biogas is too toxic for humans to breath. It addition it has a very objectionable odor.
Cold return water entering a boiler can cause high levels of thermal stress, called thermal shock. This thermal shock can be the cause of constant and expensive repairs of the boiler, almost always leading to premature failure and replacement.
The steel boiler in Figure 1 offers a very innovative construction to distribute the stresses associated with water returning to the boiler being too cold. Unlike most steel boilers, the L.E.S. boiler does not contain a large number of short stay bolts. This construction technique, combined with a U-type flex-joint between the furnace and the front tube sheet, serve to minimize thermal stress and shock damage to the boiler. This allows the boiler to safely operate over a wider range of delivery and return temperatures.
The Webster burner and all of its support components were selected specifically for their ability to:
o Provide stable and complete combustion of the biogas fuel. The small amount of H2S present in the Biogas is the culprit, which makes the gas toxic to humans. This molecule in the gas is rendered it harmless in the very high temperatures developed in the biogas flame.
o The components that come in into direct physical contact with the biogas were all engineered specifically to provide many years of excellent service thereby limiting expensive repairs.
o Stainless steel pipe is used to stop the corrosion, which causes leaks in black iron pipe that leads to human exposure to this dangerous gas.
This system, like all systems, will require periodic inspections, maintenance, and adjustment to ensure that everything is working properly. But this customer has taken one additional step to ensure that between checkups the system will automatically control itself to maintain its very high combustion efficiency.
In place of the old style linkage controls (shown in Figure 2) with a single modulation motor driving the air damper, the biogas flow control valve and the back up natural gas fuel flow control valve through interconnected linkage, Power & Heat supplied a Honeywell ControlLinks system which eliminates all the interconnecting linkage and inherent variations in fuel-air mixtures. Each of the flow control devices has
their own, very accurate (+0.1o angularity) positioning system for each of two independent fuels to maintain their own specific air control curve. The control maintains the fuel-air setting at all firing rates between tune-ups.
The linkage-less control system allows each fuel, the primary biogas and the back up natural gas or oil fuel, to have it own unique air-to-fuel curve. The system allows for a more efficient combustion setting for each of the fuels and will meticulously maintain that efficiency from tune up to tune up.
The technology applied to this project can be applied to most boilers with savings that offer real paybacks. Boiler owners can reduce their energy cost enough to cover the cost of improvements and provide added profits, help reduce our dependence on fossil fuels, and to be better environmental stewards by producing fewer greenhouse gases.
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The greenhouse industry is very strong in Virginia and while our winters may not be as cold as many states north of us, those people in the greenhouse industry still have to very closely watch the temperature and humidity conditions in their houses. The energy cost to get through even a Virginia winter can be a major portion of the cost of growing the flowers, plants and vegetables we all enjoy.
To maximize the energy available in their fuel one major grower has started the process of replacing older obsolete dual fuel burners with state-of-the-art burners and controls. As soon as the first burner was installed and operating it was obvious to the owner of this large greenhouse that he had made the right decision. The new Webster burner turned on and was able to fire each of its two fuels with the maximum efficiency.
To achieve the maximum fuel to hot water efficiency the new burners were equipped with a Honeywell Control Links, linkage-less burner firing system. This new system allow the start up technicians to set the absolute best air and fuel firing rates for each fuel from low fire to high fire. Once set, the installing contractor knows the control will hold those setting up and down the firing range today, tomorrow, and all winter or all year for a process boiler.
A separate actuator or drive motor is supplied for the air damper, the gas flow control valve and the oil flow control valve. Each actuator communicates back to the Honeywell Control Links drive module
which ensure that every firing position returns to its original setting within a maximum variance of one tenth of an angular degree every time. This type of accuracy was never achievable with old style linkage systems. Even when these older systems were new, variations of one or more degrees at every set point
was common and unavoidable.
The new system allow the start up technician to set the excess air levels lower sending fewer wasted Btu’s up the stack; and with systems like the Honeywell Control Links the initial cost is only slightly more than a standard burner. Systems like this can provide paybacks in one or two years and on some older systems have even shown paybacks in less than one year.
Original Kewanee Burner 300 HP
Stack Oxygen Level – % 6.50 %
Excess Air Level – % 36.50 %
New Webster Burner 300 HP
Stack Oxygen Level – % 3.90 %
Excess Air Level – % 21.20 %
Btu/hr saved 130,606
Gallons/hr saved 1.4
The chart shows the old burner and the new. It also shows the fuel savings in Btu/hr. Since this customer was using propane as their gas fuel, we are also showing the gallons of propane saved. And with the Control Links system, these savings will continue for the full heating season.
If your heating or process steam bill seem to be getting higher and out of hand, call the professionals at Power & Heat and we can help you and your local contractor get control or your energy cost.
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When a major Virginia university made the decision to renovate one of their buildings, they followed the standard best practices steps: bring in a good engineering firm, develop comprehensive specifications, and then select the most qualified contractor offering the best price.
An Ajax boiler featuring Webster burners not only met the specification, but more importantly, offered the best value for the university’s budget dollar. A quick turnaround on the project submittals, plus on-time delivery of the equipment, ensured that this project would be completed on time and with no surprises.
The end result is a product that performs as advertised and boasts a finished appearance that speaks quality to anyone entering the boiler room, including the owner. But with today’s high energy costs, it is simply not enough for the installed equipment just to look good. The real test is performance. Here again the Ajax line of boiler room equipment excels by offering the greatest possible energy efficiency.
And Ajax stands behind their products. With over eight decades of experience, the company offers high-quality heavy-duty products with a reputation for reliability, serviceability, and cost-effective
The university’s new boilers are standard models with a 20 year thermal shock warranty. Both the boiler and burner are specifically designed to feature ease of service, resulting in lower maintenance costs. Additionally, the Webster burner features the most reliable pilot system available in the industry. Ajax boilers — reliable, serviceable, and cost-effective.
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