Concurrent Reduction of Draft Height and Heat-Exchange Area for Large Dry Cooling Towers

1974 ◽  
Vol 96 (3) ◽  
pp. 279-285 ◽  
Author(s):  
F. K. Moore ◽  
T. Hsieh
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Full Description ◽  
Large Power ◽  
Water Pumping ◽  
Exchange Area ◽  
Fold Reduction ◽  
Water Side ◽  
Dry Cooling Tower ◽  
Dry Cooling

A procedure is outlined to meet simultaneous requirements to reduce overall size of a dry cooling tower for a large power plant, and to reduce the size (surface area) of the associated air-water heat exchanger. First, tower exit dimensions (or fan power) are specified as attainable fractions of their theoretical minima as found from a draft equation. Then a heat-exchanger type is chosen, having as small an air hydraulic diameter as feasible. Appropriate equations and assumptions dealing with air side and water side heat exchange and water pumping power then yield a full description of tower and heat-exchanger characteristics for a given tower duty. A specific example is worked out and compared with the tower at Rugeley, England. We find that a very open heat exchanger, of shallow depth (one in or less) results from our analysis, and in a proposed configuration of acceptable header loss gives a 1/3 height reduction and a four-fold reduction of heat-exchanger area.

Preliminary Design of Dry Cooling Tower for the Closed Cycle Gas Turbine HTGR

1981 ◽  
Author(s):  
A. Montakhab
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Cooling Tower ◽  
Waste Heat ◽  
Cross Flow ◽  
Preliminary Design ◽  
Closed Cycle ◽  
Natural Draft ◽  
Dry Cooling Tower ◽  
Dry Cooling

Because of its relatively high coolant temperature, the closed cycle gas turbine HTGR is well adapted to dry cooling and its waste heat can be rejected with relatively low cost. The preliminary design of natural-draft dry cooling towers for a 1200 MW(e) GT-HTGR is presented. The effects of air approach velocity, capacity rates of air and water mediums, and number of heat exchanger cross flow passes on salient tower and heat exchanger dimensions are studied. Optimum tower designs are achieved with three cross flow passes for the heat exchanger, resulting in a simultaneous minimization of tower height, heat exchanger surface area and circulating water pumping power. Four alternative tower designs are considered and their relative merits are compared. It is concluded that the 1200 MW(e) plant can be cooled by a single tower design which is well within the present state of the natural-draft dry cooling tower technology. In comparison, the fossil-fired or HTGR steam plants of the same output is shown to need three such towers.

scholarly journals MULTI-FACTOR HEAT EXCHANGER DESIGN MODELS

2021 ◽  
Vol 2 (37) ◽  
pp. 49-54
Author(s):  
R. Klimov ◽  
E. Lusta
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Regression Equations ◽  
Simple Formulation ◽  
Finned Tubes ◽  
Heat Exchanger Design ◽  
Exchange Area ◽  
Compactness Factor ◽  
Shell And Tube ◽  
Fisher’S Criterion

Compressed air is widely used in enterprises, and it is possible to reduce air consumption on pneumatic devices by heating. Most often, heating is carried out in shell-and-tube heat exchangers. To increase the area of heat exchange between the heating medium and the air, finned tubes are used, which can significantly reduce the volume occupied by the heater. The design of the heater is influenced by many factors, and the importance of the influence of each of them can differ significantly. It is advisable to use the overall characteristic in the form of a compactness factor, which shows the ratio of the heat exchange area to the volume of the heater. The work developed a method for determining the optimal design of heaters by such a parameter as the compactness factor. The obtained regression equations make it possible to determine the influence of such factors as the number of rows of tubes across the flow and the length of one tube on the volume occupied by the heat exchanger and the compactness factor. According to Fisher's criterion, the equations of the model are adequate to the true dependence with a confidence level of 95%. Most of all, the volume of the heat exchanger and the compactness are affected by the number of tubes transverse to the air flow. Changing the length of one tube does not fundamentally affect the obtained values of the output parameters. With an increase in the length of one tube and their number across the flow, it is possible to achieve the highest values of the compactness coefficient, the dependence of which on the main factors has a pronounced maximum. Using the developed technique, it is possible, in a fairly simple formulation, to analyze the value of the compactness factor for various combinations of the above factors and to optimize the design of the heater.

Synthesis Method of Heat Exchanger Network for Distillation Device

2011 ◽  
Vol 199-200 ◽  
pp. 1509-1512
Author(s):  
Yu Lin Ge ◽  
Ping Wang ◽  
Sheng Qiang Shen ◽  
Jun Liang Xu
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Heat Load ◽  
Programming Model ◽  
Synthesis Method ◽  
Total Heat ◽  
Heat Exchanger Network ◽  
Exchange Area ◽  
Heat Exchange Network

Mathematical programming model for synthesis of heat exchanger network for distillation unit is established. MINLP problem for heat exchanger network is solved by branch-bound method. Two kinds of heat exchanger network with splitting stream and without splitting stream are obtained. 142 heat exchangers, 8 coolers and 4 heaters are needed in the heat exchanger network without splitting stream. 34 heat exchangers, 8 coolers, 4 heaters, 11 splitters and 11 mixers are needed in the heat exchanger network with splitting stream. The matching situation including heat load, heat exchange area, duty of utilities, flow fraction of splitting, temperature of inlet and outlet, etc. for cold and hot streams in the heat exchanger network with splitting stream is presented in detail, Analysis the relationship between total heat exchange area, total heat load, total capital cost and annual operation cost of the heat exchanger network. Taking the number of heat exchangers and operational flexibility of heat exchange network into consideration, the heat exchanger network with splitting stream is suggested to be selected.

Modeling of a Rotary Dry Cooling Tower

1981 ◽  
Vol 103 (4) ◽  
pp. 715-719 ◽  
Author(s):  
J. A. Valenzuela ◽  
L. R. Glicksman
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cooling Tower ◽  
Thick Layer ◽  
Hot Water ◽  
Rotating Disks ◽  
Air Stream ◽  
Additional Resistance ◽  
Dry Cooling Tower ◽  
Dry Cooling

A novel design of a rotary heat exchanger to be used as a dry cooling tower is described. The heat exchanger consists of a matrix of thin steel disks which rotate between a hot water bath and a forced draft air stream. On top of the water floats a 2 cm thick layer of oil which coats the rotating disks and thus eliminates evaporation. An analytical model of the heat exchanger was developed and validated with experimental measurements taken on a 1.5 m dia test section. The model was then used to determine the net effect of the oil on the heat transfer performance. Although the oil film that coats the disks presents an additional resistance to the transfer of heat, it also contributes to the heat capacity of the disks. It was found that the reduction in the overall heat transfer rate due to the presence of the oil is small, of the order of 5 to 10 percent.

Details Study of Ambient Wind Effect on Heat Dissipation Capacity of Thermal-Powerplant Dry Cooling-Towers

2014 ◽  
Author(s):  
Masoud Darbandi ◽  
Ali Behrouzifar ◽  
Ahmad Mirhashemi ◽  
Hossein Salemkar ◽  
Gerry E. Schneider
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Heat Dissipation ◽  
Cooling Tower ◽  
Wind Effect ◽  
Circulating Water ◽  
Wind Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
Dry Cooling Tower ◽  
Dry Cooling

Thermal powerplants report a reduction in their dry cooling tower performances due to surrounding wind drafts. Therefore, it is very important to consider the influence of wind velocity in cooling tower design; especially in geographical points with high wind conditions. In this regard, we use the computational fluid dynamics (CFD) tool and simulate a dry cooling tower in different wind velocities of 0, 5 and 10 m/s. To extend our calculations; we also consider the temperature variation of circulating water through the tower heat exchanger or deltas one-by-one. We show that some heat exchangers around the tower cannot reduce the circulating water temperature sufficiently. This causes an increase in the mean temperature of those heat exchangers. The worst performances can be attributed to heat exchanger located on side wind places. We will discuss the detail performance of each delta and their assembly in draft wind conditions. This study suggests some effective ways to overcome thermal-performance of cooling tower in wind conditions.

Study on Thermal Characteristics of the Regenerative Heat Exchanger

2016 ◽  
Author(s):  
Junping Si ◽  
Mingyan Tong ◽  
Wenhua Yang ◽  
Gang Huang
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Characteristics ◽  
Outlet Temperature ◽  
Regenerative Heat ◽  
Regenerative Heat Exchanger ◽  
Exchange Area ◽  
Cooling Section

The regenerative heat exchanger is widely used in nuclear power plants and research reactors. It is composed of the regeneration section and the cooling section. The heat transfer mainly occurs at the cooling section, while the regeneration section is designed to reduce the temperature difference between the hot and cold fluids and weaken the damage to the heat exchanger due to the existence of thermal stress. Meanwhile, some heat is also can be recovered through the regeneration section. This paper mainly aims to analyze the thermal characteristics of the regenerative heat exchanger according to its structure properties, and provides some suggestions for regenerative heat exchanger design based on the influence of some key factors on thermal characteristics. The results show that improving the outlet temperature in the regeneration section primary side can both reduce the heat exchange areas of the regeneration section and the cooling section, but this will rise thermal shock and increase the operation safety risk. The baffles arrangement will enhance heat exchange capacity, and the heat exchange area decreases with the baffle gap height increasing. With the heat exchange area margin of the regeneration section improvement, the actual power will gradually reduce. The measures, including increasing secondary water flow or taking a corresponding margin about 52.8%∼59.2% that of the regeneration section for the cooling section heat exchange area, can be taken to overcome the adverse effects of the margin on the regenerative heat exchanger. More heat exchange areas of the regeneration section and the cooling section are required to satisfy the rated power with the fouling thermal resistance of the primary water increasing. Moreover, adopting a lower fouling coefficient favors the generative heat exchanger running under the design power.

Waste Heat Disposal to Air with Mechanical and Natural Draft—Some Analytical Design Considerations

1980 ◽  
Vol 102 (3) ◽  
pp. 719-727
Author(s):  
Ali Montakhab
Keyword(s):  
Cooling Tower ◽  
Waste Heat ◽  
Cooling Towers ◽  
Large Power ◽  
Natural Draft ◽  
Power Stations ◽  
Influence Coefficients ◽  
Design Variables ◽  
Dry Cooling Tower ◽  
Dry Cooling

There is a growing acceptance of the future necessity of dry and wet/dry cooling tower systems for large power stations in spite of their economic penalty compared with once-through cooling, cooling ponds, and evaporative cooling towers. If technological improvements succeed in reducing the current costs of dry cooling towers, their future applications will be accelerated. The main objective of this work is to quantify the factors that reduce the overall size and cost of the tower and the associated heat transfer system and to provide a basis for establishing the conditions that result in dry cooling tower cost reductions. As a first-step, the design equations for forced-and natural-draft dry cooling towers are derived in close form to give explicit relations for salient design variables. Subsequently, these equations are used to establish a set of influence coefficients for quantifying the effects of various key design variables on the design of forced- and natural-draft cooling towers.

Analysis of Heat Transfer Surface Geometries for Dry Cooling Tower Applications

1980 ◽  
Vol 102 (4) ◽  
pp. 807-812 ◽  
Author(s):  
Ali Montakhab
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Heat Transfer Surface ◽  
Per Se ◽  
Fin Tube ◽  
Dry Cooling Tower ◽  
Heat Exchanger Surface ◽  
Dry Cooling

An analysis of heat exchanger surface geometries for the purpose of reducing dry cooling tower cost is presented. Two sets of results are derived. The first set can be used to evaluate heat transfer surface geometries in an attempt to select those most suitable for dry cooling tower applications. The second set of results can be used to direct research and development efforts toward developing better geometries for dry cooling tower applications. The first set of results is general and is applicable to all heat exchanger surface geometries. The second set is valid only for helical round or continuous fins having smooth, serrated, or cut fins and for staggered and in-line tube arrangements. The methods developed in this paper are not restricted to dry cooling towers per se, but are valid for other applications of fin tube heat exchangers as well.

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