Plant Hatch Cooling Towers An Innovative Prototype
COVER FEATURE Plant Hatch Cooling Towers An Innovative Prototype Keith D. McCartney Sales and Marketing Tindal l Concrete V irginia, Inc. Petersburg, Virginia Bryant Zavitz Vice President Produ ct and Process Development Tindal l Concrete Georgia, Inc. Conl ey, Georgia Douglas A. Leisy Project M anager H amon Cooling Towers Bridgewater, New j ersey The twin 8 million cooling towers recently built for Georgia Power Company at Plant Hatch in Baxle Georgia, represent a significant step forward in the design and construction of mechanical draft cooling towers. Precast, prestressed concrete products played a prominent role in rapidly building the two 12-ce /1 cooling tower structures. This unusual project was the culmination of a sound design-build partnership between Tindall Concrete and Hamon Cooling Towers. Out of this relationship cam e a prototype incorporating some unique and innovative concepts for blending together both standard and custom designed products and details to produce two effic ient cost effective and highly durable finished structures. This article discusses the design concept, design considerations and stru ctural innovations of the project, together w ith a description of the production, transportation and erection of the precast components. ntil about 20 years ago, the typical image of a cooling tower for a large nuclear power plant was a tall, semispherically shaped edifice, huge and dome-like in appearance. These tall, wide, hyperbolic towers, which are natural draft cooling towers , require gigantic size to function properly. Although the operational costs of such natural draft towers are extremely low, very few of them have been built in the last 20 years, primarily because of the extremely high initial expense of the structures. In contrast, mechanical (induced) draft cooling towers are more compact and less expensive to construct, but have U Gary R. Mirsky Vi ce President of Sa les Hamon Cooling Towers Bridgewater, New j ersey 12 PCI JOURNAL
Fig. 1. Plant Hatch Cooling Towers, Baxley, Georgia. very high operating costs compared to the natural draft towers . This is because they use energy to drive large fan motors at the roofs to induce a tremendous amount of airflow through the structures. Mechanical draft cooling towers , like their large dome-like counterparts, are designed to reduce the temperature of water heated by various power generating processes by bringing it into contact with air. The hot water is pumped from the generating station into distribution piping in the cooling tower, then sprayed onto a heat exchange medium called fill. As the water percolates down through the fill , air is brought up through the fill by fans mounted on top of the structure. The Plant Hatch Cooling Towers (see Fig. 1) built by Hamon Corporation of Bridgewater, New Jersey, use 24 200-horsepower fan motors at the roofs to induce the airflow. As the air and water pass each other inside the fill , cooling takes pl ace through the exchange of heat between the hot water and cooler air and , more importantly, the evaporation of a portion of the hot water. The cooled water is continuously collected in a basin beneath the fill and pumped back into January-February 1997 the coo ling system of the power plant. Mechanical draft cooling towers for major utilities have traditionally been constructed from wood or concrete, with a more recent industry trend toward the use of fiberglass. Hamon Thermal Engineers and Contractors, an 85-year-old international corporation headquartered in Brussels, Belgium, supplies all types of cooling towers to a broad client base throughout the world. The governing criterion for the choice of building method has historically been weighing initial cost against life cycle benefits, along with overall cooling volume requirements. Particular emphasis by owners is placed on the length of the payback period as a determinant in the choice of systems. Wood towers are less expensive than fiberglass or concrete, so they have a significantly shorter payback period. Concrete cooling towers, especially those made from precast concrete, are recognized as being the most durable and are usually specified where longevity is desirable and a longer payback period is more acceptable. Many applications also require that the structural system of the tower have a certain fire rating, which automati- cally precludes the use of wood. Fiberglass also has difficulty meeting the fire rating criteria for many cooling tower applications. Hamon 's previous precast concrete cooling tower design had been based on conventionally reinforced members without prestressing. Although this system has proven itself marketable over the years in certain parts of the world, it has not been competitive in the United States. Hamon Cooling Towers, the New Jersey based division of the parent company, was seeking a better solution. Knowing of Tindall Concrete Virginia's history of innovation in industrial construction,* Hamon Cooling Towers contacted the firm in 1994 with a major challenge: to develop a precast concrete cooling tower structural system that was competitive as well as compatible with both parties' products and processes. The system needed to offer superior performance and durability that would meet the need s of Hamon 's demanding customers in the power and industrial sectors. * Tindall Concrete has pioneered the development of precast, prestressed concrete systems for pulp paper mill s, food process ing plants and other industrial facilities. 13
B I L.EYEL ERAMNl PLAN -o Q '-- 0 c f:: Fig. 2. Fill leve l framing plan. Layout shows double beams and tri-beams spann ing from doub le tee wa ll s at perimeter to solid loadbearing wal ls at centerlin e of tower. Stainless stee l truss system shown for lateral stabi lity was required at fill level only.
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-- 1 I l r --- j "1 t: v I PL.W -o Q c: 0 c JJ z ) r Fig. 6. Interior elevation and transverse sections of 12-cell cooling towers. A. Transverse cell divider walls shown with openings at bottom for water flow. These walls functioned as shear walls in transverse direction. B. Transverse section through two back-to-back cell s showing the three supported operating levels . C Section show ing interior windscreen wa ll requi red as part of Hamon's design. --··- rr '
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In short order, a sound partnership formed between Hamon and Tindall, which allowed for the careful design and development of a system of prestressed concrete elements that could be produced, delivered and erected as economically as possi ble and still meet the unique functional requirements of these unu sual structures. The first two structures from this prototype design were erected at Plant Hatch. If it had been implemented on the Plant Hatch project, the conventional Hamon design would have resulted in many more separate elements with thicker sections, narrower widths, and shorter length s, all resulting in more Fi g. 10. Tri -beams in storage fo r fill/distribution leve ls. Fig. 11. Erection of first tower. At this constru ction phase, about o ne-third of the structure was compl eted . 22 Fig. 12. 50ft (15.2 m) long perimeter loadbea ring walls being erected during ea rl y phase of constru ction . PCI JOURNAL
individual pieces to produce , ship , erect and connect in the field. Tindall worked with Hamon to consolidate these elements into fewer components by maximizing widths and lengths of members. By doing so, a cost-saving "domino" effect was realized. Efficiencies and reductions in production, plant handling, shipping, and erection and connection hardware were all realized. A dramatic improvement in the overall construction schedule was an additional benefit. Georgia Power's decision to hire Hamon Cooling Towers as its turnkey contractor for the two major 12-cell towers at its Plant Hatch Nuclear Facility in Baxley , Georgia, was based on economics and a rapid schedule. Georgia Power also expressed confidence in the life cycle and durability characteristics of the precast/prestressed structural system supplied by the Hamon/Tindall team. The amount of cooling capacity needed and the volume of air and water flow involved required 24 cells, 48 x 50ft (14.6 x 15 .2 m) in dimension , to be constructed in two separate dual-line towers. The building dimensions for each tower were 96 ft 2 in. x 302 ft 6 in . (29.3 x 92.2 m) in plan and 49ft 10 in. (15.2 m) high overall. Each cell in both towers has a basin level several feet below grade, a fill level approximately 21 in. (533 mm) above the basin floor, a distribution level about 13 ft (3.9 m) above the fill level, and a roof or fan-deck level above surrounded by a 3 ft 6 in. (1.06 m) parapet. Plan and elevation views of the structure together with typical cross sections are shown in Figs. 2 through 9. Fig. 13. Shot from basin floor showing fill , distribution and fan deck levels. Fig. 14. Interior view midway through erection phase showing fill and distribution level framing. ERECTION SCHEDULE Scheduling and speed of erection were critical considerations in this project because the power plant was in full operation with older towers in use. Erection of critical components of the new towers had to take place during two-week shutdown periods, with definjte beginning and ending times. Precast, prestressed concrete was ideal for these conditions because production and shjpping could be planned and executed according to the window of opportunity. January-February 1997 Fig. 15. Roof (fan deck level ): 200 horsepower motor mounted on plant cast pedestal between adjacent double tee stems. Notice large area of flange block-out for airflow. 23
Fig. 16. Exterior elevation showing towers nearing completion. STRUCTURAL DESIGN INNOVATIONS Several innovative concepts made the cooling tower prototype successful: 1. Use of typical prestressed members whenever feasible , which were amenable with Tindall's form inventory. Members were efficiently sized in a modified format to meet the aerodynamic and hydrodynamic functional requirements of the structure. One of the most important products driving the economy of the towers was the loadbearing double tee along the perimeter, with removal of the entire flange area between the stems in the lower half of the members . This al- lowed for single-component construction for the full height of the tower using a modified 10 ft (3 .05 m) wide standard member. Hamon's technical engineers were not accustomed to dealing with this pattern of openings on 5 ft (1.52 m) centers and had to perform extensive evaluation to integrate this pattern into their overall system design. Much scrutiny was even given to the amount of draft on the remaining stems of the wall panels and how this would affect overall airflow activity. In addition , the system incorporated single-component flat interior wall panels with large intermediate openings for water flow rather than the conven- Fig. 17. Large distributor pipes feed hot water into individual cells at the distribution level to begin the cooling process . 24 tiona! column-to-beam framing that is typically seen in other tower designs. This interior wall concept, as opposed to a column-to-beam layout, also provided shear walls for lateral stability. 2. A second key to the overall economy of the two structures involved the consolidation of many single-span beams at the upper fill and distribution levels into a fewer number of two- and three-beam section members, which became, in effect, double-stem beams and triple-stem beams with intermittent transverse connecting diaphragms. This consolidation of many members into fewer components allowed for overall lower erection and production costs . In addition , fewer Fig. 18. Exterior tower end walls showing fill level beams framed in perpendicular direction. PCI JOURNAL
components meant fewer exposed connections, less expensive stainless steel and reduced concern regarding long-term corrosion. 3. A third innovation with an obvious economic benefit was the use of standard 25 in. (635 mm) deep, I 0 ft (3.04 m) wide double tees for the roof (fan deck level). The gross open area of 908 sq ft (84 m2) required for the massive uplift airflow generated by the 200-horsepower fans at this level was achieved by removing (blocking out) approximately 40 percent of the total double tee flange area per each individual cell. Five double tees per cell clear spanning 50ft (15.2 m) were used to frame the fan deck level in place of cumbersome member framing to frame out and around these large openings so often seen in other tower designs. The aerodynamics of this design solution were also carefully studied and analyzed before being approved by Hamon's engineering staff. 4. A fourth cost benefit was realized by stabilizing the structures laterally in both the longitudinal and transverse directions with shear walls. This was easily accomplished by taking advantage of the overall open and closed wall design, thereby avoiding costly and cumbersome frame action connections usually required in other tower designs . SPECIAL DESIGN CONSIDERATIONS Among the special design considerations were the following: Connections Durability and corrosion protection of reinforcement Lateral stability of the structure Vibration/torsion at roof level to accommodate fan operation FiiJ level diaphragm Connections To provide superior corrosion protection, grouted sleeved connections were used in place of welded or bolted connections wherever reasonably possible. This applied to all foundation connections and some limited elevated connections as well. For added measure, a crack protection coating (Sikadur 30) was applied in the field at the bottom of the precast members near the foundation after they were erected. The type of connection hardware specified for precast concrete cooling towers for exposed conditions is normally governed by the corrosive quality of the water being cooled. When cooling towers are operative, they are usually completely wet inside and out, 24 hours a day. If the water is slightly saline or brackish, the corrosive im- Fig. 19. Interior shot of typical cell at basin level. Note succession of cell divider walls in background. January-February 1997 pact on exposed connections can be devastating. In certain salt water environments the connection hardware specified is often an aluminum-bronze or siliconbronze aiJoy, which is much more expensive than stainless steel but many times more resistant to corrosion. Fortunately, the chloride content of the water for this project required only that stainless steel be used for all exposed connection hardware. Flat wall panels, double tee panels and column-to-foundation connections - Cast-in-place emulating connections were required , with no exposed steel, because of the permanently submerged condition of these areas at the tower basins. More specifically, concealed grouted dowel connections were used: #7 dowel bars were epoxy grouted into 12 in. (305 mm) deep drilled sleeves at the foundation with a 30 in. (762 mm) projection of the reinforcing steel. Members with sleeves cast at the bottom were erected and set overtop projecting dowels and grouted solid via strategically positioned grout ports. The 7 ft 6 in. (2.3 m) long pipe support beams at the distribution level were also connected using completely concealed epoxy grouted dowels. Connections above the foundation (precast to precast) - A wide vari- Fig. 20. Basin level perimeter. Loadbearing exterior double tee wa ll panels connect at foundation below water level. 25
ety of welded and bolted stainless steel connections were used throughout the structure to guard against the problems that might be caused by corrosive conditions. Durability and Corrosion Protection of Reinforcement The performance and life cycle value of concrete elements used in cooling towers, whether for industrial or commercial uses, depends on protecting the reinforcing steel. Fortunately, because of the relatively low level of chloride in the water produced by the Plant Hatch process, corrosion inhibitors or silica fume additive were deemed unnecessary. However, Tindall did maintain a low water-cement ratio of 0.37 maximum to lessen the permeability of the members to water and ion penetration. In addition , for the flanges of the wall and roof double tee members , where concrete cover was somewhat minimized, galvanized mesh was used in place of uncoated steel for additional protection. Lateral Stability of the Structure Shear wall design to brace the structures laterally in both the longitudinal and transverse directions was utilized in place of frame action more often seen in structures of this type. Diaphragm action at the roof level with the large circular opening at each cell was achieved through intermittent welded, stainless steel, flange-to-flange connections [3 in. (76 mm) double tee flange thickness] . A 2 in. (51 mm) thick composite concrete topping was poured in the field by Hamon. Vibration/Torsion at Roof Level to Accommodate Fan Operation The torsion and vibration thrown into the roof diaphragm from the operation of the large 200-horsepower fans, one at each cell, and the potential for possible eccentric loading from this was accommodated through the conservative diaphragm design. These effects were also minimized by thickened support pads, or pedestals, that were monolithically cast on top of double tee roof members fabricated at Tindall's plant in Conley , Georgia. These pads directly supported the motor and gear box of each unit. Directly under this thickened pad section of double tee, at midspan of the tee, was a separate beam specially designed to provide additional support and torsion resistance. The double tee from the top of its thickened pad section was bolted down to this beam with large stainless steel rods epoxygrouted deep into the underlying beam section. Fill Level Diaphragm At the level of the fill , which the water passes over during the cooling Fig. 21. Exterior elevations of both new towers prior to startup. Steam in background from existing towers. 26 process , diaphragm action was achieved by using a custom designed stainless steel distribution truss. DESIGN PHASE The project was awarded in mid to late January 1995, allowing for ample design time for Tindall and Hamon to work out the various particulars relative to the new prototypical design concept, before the need to begin casting the product. In addition, the extra time allotted ensured a comfortable schedule for the fabrication and delivery of the custom steel forms required at Tindall's Jonesboro facility . PRODUCTION OF PRECAST COMPONENTS A large variety of standard and specially designed precast, prestressed concrete components were fabricated for this project. All of the products were manufactured by Tindall Concrete Georgia, Inc., a PCI Certified Producer Member with more than 30 years of proven reliability and experience. A total of 736 precast, prestressed concrete components were produced, a description of which follows: 17 in. (432 mm) deep LOft (3.04 m) wide double tee wall panels with a 49ft 6 in. (15.1 m) clear span from basin floor to top of parapet, with all flange elements blocked out in the lower 24 ft 7 in. (7 .5 m) of each panel for air and water flow require- Fig. 22. Overhead shot showing tower at upper right in operation, lower tower equipped and nearing completion. PCI JOURNAL
ments: 184 components per 84,700 sq ft (7868 m2) 25 in. (635 mm) deep 10ft (3 .04 m) wide double tees at roof (fan level), with 47 ft 9 in. (14.5 m) spans, also with excessive amount of flange blocked out for airflow requirements: 120 components per 57,200 sq ft (5313 m2) 16 x 16 in. (406 x 406 mrn) precast columns (one per cell): 24 components per 1110 ft (338m) 8 in. (203 mrn) solid, 10ft (3.04 m) wide loadbearing wall panels at the longitudinal center all , supporting beam and double tees on both sides: 60 components per 28,080 sq ft (2608 m) 6 in. (152 mm) solid, 12 ft (3.6 m) wide non-loadbearing divider walls with large block-out openings at bottom for water flow: 80 components per44,585 sq ft (4141 m 2) 32 in. (813 mm) deep double-stem beams and triple-stem beams at the fill level: 96 components per 4,585 ft (1397 m) 28 in . (711 mm) deep double-stem beams and triple-stem beams at the distribution level : 95 components per 4,585 ft (1397 m) Production of the precast components for the two 12-cell towers at Plant Hatch took place at three of five different Tindall plant locations: Conley, Georgia, Biloxi, Mississippi, and Jonesboro, Georgia. Tindall ' s plant in Biloxi produced all of the custom designed triple-stem beam and doublestem beam members. All remaining products (425 of the total 736 components) were manufactured at the large prestressing plant in Conley, Georgia. The production cycle was approximately 12 weeks and lasted from June through August 1995. Fig. 23. Overhead shot showing tower at upper right in operation, lower tower equipped and nearing completion. TRANSPORTATION OF PRECAST PRODUCTS Aside from the normal "overwidth" permits required for the 12 ft (3.66 m) wide products and special extra wide dunnage for the triple-stem beams, no unusual shipping and/or handling costs were incurred in the process of transporting the unusual variety of products for the project to the site. Both the Conley and Jonesboro plants January-February 1997 Fig. 24 . End elevation. Initial start-up of first completed tower with large flume in foreground . are located approximately 210 miles (340 km) from the Plant Hatch jobsite. The double tee loads coming from Biloxi had two, sometimes three, components per load to help minimize the higher freight impact due to the greater distance involved [300 miles (484 km) from the site]. The fact that so much of the tee flange was blocked out helped to lighten these members considerably, making these multiple member loads possible. 27
Fig. 25. Completed view of Hatc h Coo ling Towers. ERECTION HIGHLIGHTS Figs. 10 through 24 show various construction phases of the cooling towers. A 200 ton (181 t) truck crane was used to erect elements for both 12-cell towers. The interior concrete basin floor thickness of 15 in. (381 mrn) allowed for comfortable access of the crane and trucks inside both tower footprints . For added protection to the 15 in . (381 mm) thick slab, special dunnage was placed under each crane outrigger to spread the loads out during erection. Erection proceeded on a cell-by-cell basis that allowed for a progressive turnover of structure for the mechanical (fill uplift, etc.) trades. In particular, fill and distribution level piping installation occurred almost immediately after erection. Due to the owner' s requirement for union labor on the site, Gibbons Erectors of Denver, Colorado, performed all the erection of precast products , with direct supervision by Tindall Concrete Georgia, Inc. The 200 ton 28 (181 t) truck crane and crew were also used to lift and set the large fans at the roof level of each cell for Hamon and to facilitate the movement of "fi ll" uplift material into the cells as well. The total duration for both towers combined (736 components) was 3 7 erection days , or slightly more than seven weeks, at an average of about 20 components per day with one crane and crew. PROJECT COST The contract amount for the precast package was roughly 3 million, with the total turnkey tower costs at about 8 million overall. Fig, 25 shows the finished cooling towers in operation. CONCLUDING REMARKS The cooling towers at Plant Hatch recently underwent the owner's thermal performance test, designed to determine whether contractual cooling requirements are being attained. These new prototypical towers at Plant Hatch ex- ceed the required performance criteria. Water enters the tower at an average 107 F (42 C) (inlet temperature) and exits the tower at 86 F (30 C) (outlet temperature). Each of the two 12-cell towers perform this function at a rate of 146,000 gallons per minute (gpm). A new design that is durable, easy to build, cost effective and aesthetically pleasing must perform as designed. Passing this performance test is absolutely vital, and in thi s application the design is not only innovative, it is viable and performs at or above specifications. Hamon's market projections suggest an increase in power plant construction in North America in the next two to three years. Although wood is cheaper in North America, it is Jess durable . Precast, prestressed concrete in this application may prove to be the solution of choice. Hamon and Tindall are continuing to investigate avenues to market this tower system throughout North America and have given price quotations for projects in California, Oregon, Mexico and Puerto Rico . At the time of this publication, Tindall and Hamon hav e jointly completed another cooling tower project in Andalusin, Alabama, incorporating ro ughly equivalent concepts and technology. CREDITS Owner: Georgia Power Company , Baxley, Georgia Architect: Hamon Cooling Towers, Bridgewater, New Jersey General Contractor: Hamon Cooling Towers, Bridgewater, New Jersey Structural Engineer (Foundation ): Hamon Cooling Towers, Bridgewater, New Jersey Structural Engineer (Superstructure): Tindall Concrete Georgia, Inc ., Conley, Georgia Precast Concrete Manufacturer: Tin dall Concrete Georgia, Inc., Conley and Jonesboro, Georgia Photographer: - Cover photograph : Mark Olencki, Olencki Graphics , Spartanburg , South Carolina - Hamon Cooling Towers, Bridgewater, New Jersey - Edgars Studio, Alma, Georgia PCI JOURNAL
Fig. 1. Plant Hatch Cooling Towers, Baxley, Georgia. very high operating costs compared to the natural draft towers. This is be cause they use energy to drive large fan motors at the roofs to induce a tremendous amount of airflow through the structures. Mechanical draft cooling towers, like their large dome-like counterparts,
The 50C cooling towers are included in the 2018 Emission Inventory with a factor applied to account for emissions Lower Dam water if is used. 2.3. Precipitation Cooling Towers The precipitation cooling towers arelarge with both significant water and air flows. There are three cooling towers (45K1, 45K2 and 45K3).
How Cross Flow Cooling Towers Work 8. How Counter Flow Cooling Towers Work . Tradional HVAC heating and cooling systems are used in schools, large office buildings, and hospital. On the other hand, Cooling towers are much larger than tradional HVAC systems . Here is the common cooling tower parts that might need to be repair or replaced .
CorelDRAW, sin embargo, no está incluido como estándar en Hatch. Resumen de características. La nueva versión de CorelDRAW SE - reemplaza Essentials X6 . Hatch Embroidery 2 : Hatch Embroidery 2 October 31, 2018 . Hatch Embroidery 2 : Hatch Embroidery 2 October 31, 2018 .
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An outlook to cooling towers of heights up to 250 m is given which are currently in conceptual design phase for new power plant projects. Keywords Natural Draft Cooling Towers, Reinforced Concrete, Power Plants Theme Cooling Towers - Design - Construction - Past, Present, Future 1. Introduction
the water used at Cooling Towers is a large percentage of the pie. Some advantages of focusing on water conservation at these locations is that they are (a) point sources and (b) actively managed by dedicated and trained personnel. Abbott Power Plant Cooling Tower, 48,934, 5% All Campus Cooling Towers, 278,684, 25% Other Campus Use, 771,675, 70%
These towers are purpose-built to achieve high thermal performance while maintaining minimum footprint. Our cooling towers are designed for multi-cell construction,thus . The KX series of cooling towers has been thoroughly tested to verify performance compliance to the CTI criteria. As a result, Nihon Spindle was awarded CTI .
American Revolution Activity Book This Activity Book contains activity pages that accompany the lessons from the Unit 6 Teacher Guide. The activity pages are organized and numbered according to the lesson number and the order in which they are used within the lesson. For example, if there are two activity pages for Lesson 4, the first will be numbered 4.1 and the second 4.2. The Activity Book .
