Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
Pursuant to the requirements of Notice of the National Energy Administration on issuing the plan 2014 for development (revision) of the first batch of professional standards in energy sector (NEA S&T [2014] No.298), the code development group has prepared this Code through extensive investigation, careful conclusion from indirect dry cooling system design experience, and wide consultation.
The main technical contents of this Code are as follows: general provisions, terms, basic requirements, meteorological parameter selection requirements of indirect dry cooling system, general layout of indirect dry cooling system, design parameter selection and calculation of indirect dry cooling system, indirect dry cooling process system and equipment, indirect dry cooling tower structure, operation and control requirements of indirect dry cooling system and test requirements of indirect dry cooling system.
Code for design of indirect dry cooling system for fossil-fired power plant
1 General provisions
1.0.1 This Code is formulated in order to make the design of indirect dry cooling system of fossil-fired power plant meet the requirements for safety, reliability, advanced technology, economy, rationality and environmental protection.
1.0.2 This Code is applicable to the design of indirect dry cooling system of fossil-fired power plants with single unit capacity of 125MW~1,000MW in newly built, renovated and expanded engineerings.
1.0.3 The design of indirect dry cooling system of fossil-fired power plants shall actively adopt advanced technologies, processes, equipment and materials proved by operation practice or industrial test.
1.0.4 The design life of indirect dry cooling process system shall be 30 years, and the design service life of the structure of indirect dry cooling tower shall be 50 years.
1.0.5 The design identification system of indirect dry cooling system shall be consistent with the identification system of the main work of fossil-fired power plant.
1.0.6 In addition to this Code, the design of indirect dry cooling system of fossil-fired power plant shall also comply with those specified in the current relevant standards of the nation.
2 Terms
2.0.1
indirect dry cooling system
cooling system indirectly exchanging the exhaust heat of steam turbine with air using air as the final cooling medium and circulating cooling water as the intermediate heat exchange medium, including indirect dry cooling system with surface condenser and indirect dry cooling system with jet condenser
?
2.0.2
indirect dry cooling system with surface condenser
indirect dry cooling system with the heat exchange between exhaust steam of steam turbine and circulating cooling water taking place in surface condenser
2.0.3
indirect dry cooling system with jet condenser
indirect dry cooling system with the heat exchange between exhaust steam of steam turbine and circulating cooling water taking place in mixing condenser
2.0.4
cooling column
column consisting of several groups of tube bundles and tube sheet cooling elements, with both ends connected with water chambers
2.0.5
louver
device for adjusting the air input of an dry cooling radiator, which consists of a frame and louver blades
2.0.6
cooling delta
triangular cooling unit composed of two cooling columns with the same length and a group of louvers with the same length
2.0.7
cooling sector
functional unit composed of several adjacent cooling deltas, with each operating under the control of a set of inlet valve, outlet valve, vent valve and exhaust device
?
2.0.8
initial temperature difference (ITD)
difference between indirect dry cooling radiator cooling water inlet temperature and radiator inlet air temperature
2.0.9
single flow pass
circulating cooling water entering from one end of the cooling column and directly flowing out from the other end of the cooling column without changing its direction
2.0.10
double flow pass
circulating cooling water flowing in from one half-side finned tube at one end of the cooling column and turning back to the other half-side finned tube through the water chamber at the other end of the cooling column, and flowing out from the same end of the cooling column as flowing in, with the water flow direction in the finned tube by which the circulating cooling water flows in opposite to that in the finned tube by which the circulating cooling water flows out
2.0.11
natural draught indirect dry cooling tower
facility cooling circulating cooling water in an dry cooling radiator by natural convection of air formed by air density difference between inside and outside the cooling tower
2.0.12
mechanical draught indirect dry cooling tower
facility cooling circulating cooling water in an dry cooling radiator by forced convection of air formed by a fan
2.0.13
indirect dry cooling tower with flue gas discharge
natural draught indirect dry cooling tower with flue gas discharge function as a chimney
2.0.14
widening platform
closed structure between the top of the cooling delta and the indirect dry cooling tower body when the cooling deltas are vertically arranged around the tower
2.0.15
design ambient wind velocity
average velocity of undisturbed ambient air for a period of 10min at an elevation 10m above the zero-meter ground outside the dry cooling tower
3 Basic requirements
3.0.1 Indirect dry cooling system should adopt natural draught indirect dry cooling tower and, if it is limited by the following conditions and it is verified by technical and economic comparison, may adopt mechanical draught indirect dry cooling tower:
1 It is difficult to arrange natural draught indirect dry cooling tower because of the limited land occupation of the plant site;
2 The temperature is low in winter or it is difficult to prevent freeze for heating unit by adopting natural draught indirect dry cooling tower.
3.0.2 The selection of indirect dry cooling system with surface condenser and indirect dry cooling system with jet condenser shall be determined by technical and economic comparison, comprehensively taking into account factors such as condenser terminal difference, control of circulating cooling water and condensate water quality, system power consumption, design and manufacturing level of mixing condenser and pressure regulating hydraulic turbine.
3.0.3 The exhaust steam cooling facility of steam turbine for auxiliary engine drive should be combined with main engine cooling facilities.
?
3.0.4 Special anti-freezing measures shall be taken when indirect dry cooling system is adopted in areas where the average temperature in the coldest month is less than or equal to -10℃; reasonable allocation scale and design measures for summer should be adopted if the indirect dry cooling system is used in areas with high temperature in summer; measures to prevent strong winds should be taken if the indirect dry cooling system is used in areas with high ambient wind velocity; the design of strengthening radiator cleaning system should be adopted if the indirect dry cooling system is used in areas with poor ambient air quality, including areas with more floating objects or dust in the air.
3.0.5 For units with single unit capacity of 600MW or above, each unit should be equipped with one natural draught indirect dry cooling tower.
3.0.6 The automation level of indirect dry cooling system shall be consistent with that of unit.
3.0.7 The indirect dry cooling system shall be brought under the monitoring and control of decentralized control system (DCS) of unit.
4 Meteorological parameter selection requirements of indirect dry cooling system
4.0.1 The meteorological data required for the design and design depth of indirect dry cooling system shall meet the relevant requirements of the current professional standard DL/T 5507 Regulation for basic data and depth of the hydraulic design for fossil-fired power plant.
4.0.2 The design air temperature of indirect dry cooling system shall be determined according to the meteorological data of the typical year of the reference meteorological station, and the selection of the typical year shall meet the relevant requirements of the current professional standard DL/T 5158 Technical code for meteorological survey in electric power engineering.
4.0.3 The statistics of accumulated hours of air temperature in typical years shall be arranged in descending order of air temperature from high to low, with the air temperature grading not greater than 2℃. The statistical table of accumulated hours of air temperature in typical years shall include the corresponding hours, accumulated hours and cumulative frequency of air temperatures at all grades.
?
4.0.4 The ambient wind data of indirect dry cooling system should meet the following requirements:
1 Statistical analysis of wind frequency, average wind velocity and maximum wind velocity of each wind direction in the whole year, every season and every month in recent 10 years;
2 Statistical analysis of the occurrence number, frequency and average wind velocity of each wind direction with wind velocity greater than 3m/s in the whole year and summer in recent 10 years;
3 Statistical analysis of the occurrence number, frequency and average wind velocity of each wind direction in recent 10 years when the ambient air temperature is greater than or equal to 26.0℃ and the average wind velocity for a period of 10min is greater than or equal to 4m/s and 5m/s.
4.0.5 If the altitude of the plant site is inconsistent with that of the meteorological station, the ambient air temperature and atmospheric pressure shall be corrected.
4.0.6 When designing the indirect dry cooling system, the representativeness of the selected reference meteorological station to the plant site shall be analyzed and demonstrated. If the representativeness of the reference meteorological station data to the plant site area cannot be analyzed accurately, an dry cooling meteorological observation station shall be set up in the plant site area for comparative analysis. The relevant technical requirements of the dry cooling meteorological observation station at the plant site shall meet those specified in the current professional standard DL/T 5158 Technical code for meteorological survey in electric power engineering.
4.0.7 For the design of indirect dry cooling system, the temperature inversion distribution data of the plant site area should be collected, and the relevant technical requirements should meet those specified in the current professional standard DL/T 5158 Technical code for meteorological survey in electric power engineering.
4.0.8 For the design of indirect dry cooling system, the ambient air quality near the plant site shall be subjected to the following analysis:
1 In areas with frequent sandstorms, analytic statistics shall be carried out for the season with frequent sandstorms, the longest duration of a sandstorm, the intensity of sandstorms, the dominant wind direction and the maximum wind velocity;
2 It is advisable to analyze the dirty environmental conditions such as dust and plant flocs that may affect the performance of indirect dry cooling radiator.
5 General layout of indirect dry cooling system
5.0.1 The position of indirect dry cooling tower relative to surrounding buildings shall meet the following requirements:
1 It should not be on the downwind side of the summer prevailing wind direction of the direct dry cooling platform;
2 It should not be on the downwind side of the winter prevailing wind direction of the mechanical draught wet cooling tower;
3 It should not be on the downwind side of the whole-year prevailing wind direction of the dust source;
4 It should be far away from the outdoor heat source, and should not be on the downwind side of the summer prevailing wind direction of the outdoor heat source.
5.0.2 If the radiators are horizontally arranged in the tower, the clear distance between the towers shall be calculated according to the distance between the centers of the tower pillars corresponding to the zero-meter elevation; if radiators are vertically arranged around towers, the clear distance between towers shall be calculated according to the distance between the outermost edges of radiators.
5.0.3 The clear distance between adjacent indirect dry cooling towers shall meet the following requirements:
1 For the towers with the radiators arranged horizontally inside, the clear distance between the towers should not be less than 4 times the height of the larger air inlet, and shall not be less than 0.5 times the diameter of the tower pillar center of the larger natural draught indirect dry cooling tower at zero meter;
2 For the towers with the radiators arranged vertically around them, the clear distance between the towers should not be less than 3 times the height of the higher radiator, and shall not be less than 0.5 times the diameter of the pillar center of the natural draught indirect dry cooling tower at zero meter;
3 The clear distance between the mechanical draught indirect dry cooling tower and the natural draught indirect dry cooling tower shall meet the following requirements:
1) If the radiators of the mechanical draught indirect dry cooling tower and the natural draught indirect dry cooling tower are vertically arranged, the clear distance between towers should not be less than 1.5 times of the sum of the heights of radiators of the two towers;
2) If the radiators of mechanical draught indirect dry cooling tower are arranged vertically and those of natural draught indirect dry cooling tower are arranged horizontally, the clear distance between towers should not be less than the sum of 1.5 times the height of radiator of mechanical draught indirect dry cooling tower and 2 times the height of air inlet of natural draught indirect dry cooling tower;
3) If the radiators of mechanical draught indirect dry cooling tower are arranged horizontally and those of natural draught indirect dry cooling tower are arranged vertically, the clear distance between towers should not be less than the sum of 2 times the height of air inlet of mechanical draught indirect dry cooling tower and 1.5 times the height of radiator of natural draught indirect dry cooling tower;
4) If the radiators of the mechanical draught indirect dry cooling tower and the natural draught indirect dry cooling tower are horizontally arranged, the clear distance between towers should not be less than 2 times of the sum of the heights of air inlets of the two towers.
5.0.4 The minimum clear distance between the indirect dry cooling tower and its surrounding buildings (structures) may be determined using the following equation:
Lmin≥0.4H＋h (5.0.4)
where,
Lmin——the minimum clear distance between the indirect dry cooling tower and its surrounding buildings (structures), m;
H——the effective height of the outermost air inlet surface of the indirect dry cooling tower, m;
h——the effective wind resistance height of buildings (structures) around the indirect dry cooling tower, m.
For particularly tall obstacles near the cooling tower, special research shall be conducted to evaluate their adverse effects on the thermal performance of the cooling tower.
5.0.5 If the location of the plant site has height limit requirements for the chimney, or it is proved that it is better in terms of the aspects of technique and economy to adopt the indirect dry cooling tower with flue gas discharge, the indirect dry cooling tower with flue gas discharge may be adopted after it is approved upon the environmental impact assessment.
5.0.6 If the zero-meter elevation difference between the indirect dry cooling towers of two units is greater than 2m, the unit system should be adopted.
5.0.7 The position of indirect dry cooling tower should not be at the lower point of circulating cooling water system.
5.0.8 Facilities that do not affect the heat dissipation performance and safe operation of the indirect dry cooling tower may be set in the indirect dry cooling tower in combination with the requirements of relevant process system layout and general layout.
5.0.9 If facilities with fire protection requirements are placed in the indirect dry cooling tower, fire fighting access and supporting fire fighting facilities shall be set according to the requirements of the current national standard GB 50229 Code for design of fire protection for fossil fuel power plants and substations.
5.0.10 The geometric dimension of the indirect dry cooling tower tube shall meet the thermal performance requirements of the indirect dry cooling tower and shall be determined through technical and economic comparisons in combination with factors such as reasonable structure and convenient construction. If a hyperbolic reinforced concrete tower tube is used, the geometric dimension of indirect dry cooling tower tube should be determined according to Table 5.0.10.
Table 5.0.10 Recommended geometric dimensions of shell of hyperbolic indirect dry cooling tower tube
Ratio of tower height to tower bottom (±0.00m) diameter Ratio of throat area to shell bottom area Ratio of throat height to tower height Diffusion angle at tower top
αt Meridian inclination of shell bottom
αD
1.00~1.50 0.40~0.60 0.75~0.85 3°~6° 14°~17°
5.0.11 The flue of natural draught indirect dry cooling tower with flue gas discharge should be arranged between two adjacent cooling sectors, and should be set in combination with the gate of indirect dry cooling tower.
5.0.12 The circulating water pump room of indirect dry cooling system with surface condenser should be arranged close to the indirect dry cooling tower, which may be built separately or jointly according to the number of units; the circulating water pump set of indirect dry cooling system with jet condenser should be arranged close to the steam condenser.
5.0.13 The electronic equipment room should be arranged near the indirect dry cooling tower or main equipment for the indirect dry cooling system.
?
6 Design parameter selection and calculation of indirect dry cooling system
6.1 General requirements
6.1.1 Each design condition of indirect dry cooling system shall correspond to each design condition of dry cooling steam turbine, and the design and calculation parameters shall be selected based on the parameters of corresponding working conditions of dry cooling steam turbine.
6.1.2 The design conditions of indirect dry cooling system should meet the requirements of back pressure and rating in maximum continue rating working condition of dry cooling steam turbine under the condition of design air temperature. For dry cooling units with the rating in maximum continue rating working condition as the unit plate rating, the calculated back pressure and rating in summer shall be checked according to the calculated air temperature in summer; for dry cooling units with the plate rating determined in accordance with the current national standard GB/T 5578 Fixed power plant turbine specifications, the requirements of back pressure and rating in plate rating working condition of dry cooling steam turbine under the condition of calculated air temperature in summer shall be met.
6.2 Design parameter selection of indirect dry cooling system
6.2.1 The design air temperature shall be calculated based on the hourly dry-bulb temperature of a typical year, and should be determined based on the annual weighted-average of air temperatures above 5℃, and temperatures below 5℃, if any, shall be regarded as 5℃.
6.2.2 The calculated air temperature in summer shall be reasonably determined according to the electric load requirements and characteristics of the generator set in summer, which may be selected from the hourly dry-bulb temperature statistics table of a typical year from the highest to the lowest corresponding ambient temperature for a cumulative period of not more than 200h.
6.2.3 The design ambient wind velocity shall be determined based on the statistical data of the reference meteorological station or the dry cooling meteorological observation station at the plant site, and the design ambient wind velocity should not be less than the maximum monthly average velocity.
6.2.4 The design atmospheric pressure and atmospheric pressure in summer should be determined based on the statistical data of the reference meteorological station or the dry cooling meteorological observation station at the plant site, and the former should be the average atmospheric pressure over the years, while the latter should be the average atmospheric pressure of the hottest month over the years.
6.2.5 The design relative humidity and the relative humidity in summer should be determined based on the statistical data of the reference meteorological station or the dry cooling meteorological observation station at the plant site, and the former should be average relative humidity over the years, while the latter should be the average relative humidity of the hottest month over the years.
6.2.6 The initial temperature difference shall be determined by technical and economic comparison and optimization calculation based on meteorological conditions, main engine selection, plant site layout and other conditions. The design initial temperature difference should be selected within the range of 25℃~35℃.
6.2.7 For power plants equipped with a condensation water refine treatment system, the saturated steam temperature corresponding to the calculated back pressure in summer shall match with the temperature resistance of the anion exchange resin of the condensation water refine treatment system.
6.3 Calculation of indirect dry cooling system
6.3.1 The thermodynamic calculation of the indirect dry cooling system shall meet the following requirements:
1 The heat exchange capacity of the indirect dry cooling radiator shall be calculated using the following equation:
Q1=K×S×Ft×?tm (6.3.1-1)
(6.3.1-2)
(6.3.1-3)
t1=ts-(TTD)c (6.3.1-4)
t2=t1-?t (6.3.1-5)
(6.3.1-6)
where,
Q1——the heat exchange capacity of indirect dry cooling radiator, W;
K——the total heat transfer coefficient, which is related to the water-side flow velocity and air-side wind velocity of the radiator, with the relational expression provided by the manufacturer or determined by test, [W/(m2·℃)];
S——the heat transfer area of the radiator, m2;
Ft——the correction factor of non-countercurrent heat transfer;
△tm——the average temperature difference of heat transfer, ℃;
ma——the face velocity of mass through radiator, [kg/(s·m2)];
v——the flow velocity at the water side of the radiator, m/s;
μ——the dynamic viscosity of air, Pa·s;
ts——the saturated steam temperature corresponding to the exhaust steam pressure of steam turbine, ℃;
t1——the inlet water temperature of radiator, ℃;
t2——the outlet water temperature of radiator, ℃;
?t——the inlet and outlet temperature difference of circulating cooling water, ℃;
θ1——the air temperature at the inlet of the radiator, i.e., the ambient dry-bulb temperature, ℃;
θ2——the air temperature at the outlet of radiator, ℃;
(TTD)c——the steam condenser terminal difference, ℃;
Qk——the heat exhaust of the steam condenser, W;
W——the flow rate of circulating cooling water, kg/s;
cpw——the specific heat capacity of water, 4187[J/(kg·℃)].
?
2 The heat exhaust of the steam condenser shall be calculated using the following equation:
Qk=Dk(hk-hc)+∑Dki(hki-hci)+Qs (6.3.1-7)
where,
Qk——the heat exhaust of the steam condenser, W;
Dk——the exhaust volume of the steam turbine for main engine, kg/s;
hk——the exhaust enthalpy of the steam turbine for main engine, J/kg;
hc——the enthalpy of condensation water of main engine, J/kg;
Dki——the exhaust volume of steam turbine for each auxiliary engine, kg/s;
hki——the exhaust enthalpy of steam turbine for each auxiliary engine, J/kg;
hci——the enthalpy of condensation water of each auxiliary engine (j/kg);
Qs——the exhaust volume of the drainage, W.
3 The heat absorption of ambient air shall be calculated using the following equation:
Q2=?θ×ma×Sn×cpa (6.3.1-8)
where,
Q2——the heat absorption of ambient air, W;
?θ——the temperature rise of the air, ℃;
Sn——the windward area of the radiator, m2;
cpa——the specific heat of air at constant pressure, [J/(kg·℃)];
?
6.3.2 The suction force generated by the effective height of the air duct of a natural draught indirect dry cooling tower should be calculated using the following equation:
ND=He×g×(ρ1-ρ2) (6.3.2)
where,
ND——the suction force generated due to the effective height of the air duct of indirect dry cooling tower, Pa;
He——the effective draft height of the indirect dry cooling tower, which should be the height difference from the middle of the radiator to the top of the tower if the radiator is arranged vertically, or the height difference between the average value of the top of the radiator and the top of the tower if the radiator is arranged horizontally, m;
g——the gravitational acceleration, m/s2;
ρ1——the density of cold air outside the indirect dry cooling tower, kg/m3.
ρ2——the density of hot air inside the indirect dry cooling tower, kg/m3.
6.3.3 The ventilation resistance at each part of the natural draught indirect dry cooling tower shall be calculated in accordance with the following requirements:
1 The measured data of prototype towers identical or similar to the designed indirect dry cooling tower shall be adopted;
2 If the measured data mentioned above are not available, it may be calculated using the empirical methods specified in 6.3.4 and 6.3.5 of this Code.
6.3.4 The ventilation resistance of natural draught indirect dry cooling tower may be calculated using the following empirical methods:
1 The ventilation resistance of the louver may be calculated using the following equation:
(6.3.4-1)
where,
?Pb——the ventilation resistance of the louver, Pa;
Cb——the coefficient, which is obtained by test;
m——the exponent, which is obtained by test;
vb——the face velocity of air flow passing through the louver, m/s.
2 The resistance at the inlet of the radiator may be calculated using the following equation:
(6.3.4-2)
Khi=51.601-1.335α+0.0094α2 (6.3.4-3)
where,
?Phi——the resistance at the inlet of the radiator, Pa;
Khi——the resistance coefficient of the triangle inlet of the radiator;
vh——the air velocity through the windward side of the radiator, m/s;
α——the vertex angle of the cooling delta, 40o≤α≤70o, o.
3 The resistance at the outlet of the radiator may be calculated using the following equation:
(6.3.4-4)
Kho=14.015-0.2929α+0.0017α2 (6.3.4-5)
where,
?Pho——the resistance at the outlet of the radiator, Pa;
Kho——the resistance coefficient of the triangle outlet of the radiator;
?
4 The resistance of the radiator may be calculated using the following equation:
(6.3.4-6)
where,
?Ph——the resistance of air flow passing through the radiator, Pa;
Ch——the coefficient, which is obtained by test;
n——the exponent, which is obtained by test;
5 The resistance of the air flow passing through the tower pillar may be calculated using the following equation:
(6.3.4-7)
(6.3.4-8)
(6.3.4-9)
where,
?Pd——the resistance of the air flow through tower pillar, Pa;
Cd——the resistance coefficient of tower pillar, which may be selected from those specified in Table 6.3.4-1;
ρ——the density of air flow passing through the section, kg/m3;
vd——the face velocity upstream of the tower pillar, m/s;
Ad——the total cross-sectional area of air inlet column, m2;
A——the total area of air inlet, m2;
b——the width of the tower pillar parallel to the direction of air flow, m;
d——the width of the tower pillar facing the direction of air flow, m;
Re——the Reynolds number (103
Foreword ii
1 General provisions
2 Terms
3 Basic requirements
4 Meteorological parameter selection requirements of indirect dry cooling system
5 General layout of indirect dry cooling system
6 Design parameter selection and calculation of indirect dry cooling system
6.1 General requirements
6.2 Design parameter selection of indirect dry cooling system
6.3 Calculation of indirect dry cooling system
6.4 Design margin of indirect dry cooling system
7 Indirect dry cooling process system and equipment
7.1 Indirect dry cooling radiator system
7.2 Steam condenser
7.3 Circulating water pump and piping system
7.4 Expansion water tank system
7.5 Underground water storage tank and water filling and drainage system
7.6 Radiator cleaning system
7.7 Water quality control of circulating water system
7.8 Condensation water refine treatment system
7.9 Testing and instrumentation, alarm
7.10 Insulation, painting and heat tracing
8 Indirect dry cooling tower structure
8.1 General requirements
8.2 Main structure of indirect dry cooling tower
8.3 Widening platform
8.4 Tower core structure of horizontal radiator arrangement
8.5 Accessory structure
9 Operation and control requirements of indirect dry cooling system
9.1 Startup and shutdown
9.2 Normal operation
9.3 Winter operation
9.4 Summer operation
10 Test requirements of indirect dry cooling system
10.1 Mathematical and physical model test of indirect dry cooling system
10.2 Performance test of indirect dry cooling system
Annex A Aerodynamic calculation resistance coefficient and correction factor of mechanical draught indirect dry cooling tower
Annex B Water resistance and correction factor of cooling radiator bundle
Explanation of wording in this code
List of quoted codes
Explanation of provisions
1 總則
1.0.1 為了使火力發電廠間接空冷系統設計安全可靠、技術先進、經濟合理，并滿足環境保護的要求，制定本標準。
1.0.2 本標準適用于新建、改擴建工程單機容量為125MW～1000MW級的火力發電廠間接空冷系統的設計。
1.0.3 火力發電廠間接空冷系統設計應積極采用經運行實踐或工業試驗證明的先進技術、工藝、設備和材料。
1.0.4 間接空冷工藝系統的設計壽命應為30年，間接空冷塔的結構設計使用年限應為50年。
1.0.5 間接空冷系統的設計標識系統應與火力發電廠主體工程的標識系統一致。
1.0.6 火力發電廠間接空冷系統的設計除應符合本標準的規定外，還應符合國家現行有關標準的規定。
2 術語
2.0.1 間接空冷系統 indirect dry cooling system
以空氣作為最終冷卻介質，利用循環冷卻水作為中間換熱介質，將汽輪機的排汽熱量間接和空氣進行熱交換的冷卻系統，包括表面式凝汽器間接空冷系統和混合式凝汽器間接空冷系統。
2.0.2 表面式凝汽器間接空冷系統 indirect dry cooling sys-tem with surface condenser
汽輪機的排汽與循環冷卻水之間在表面式凝汽器中換熱的間接空冷系統。
2.0.3 混合式凝汽器間接空冷系統 indirect dry cooling sys-tem with jet condenser
汽輪機的排汽與循環冷卻水之間在混合式凝汽器中換熱的間接空冷系統，又稱噴射式凝汽器的間接空冷系統。
2.0.4 冷卻柱 cooling column
由若干組管束、管板冷卻元件組成，冷卻柱兩端各有水室相連。
2.0.5 百葉窗 louver
調節空冷散熱器進風量的裝置，由框架及窗葉組成。
2.0.6 冷卻三角 cooling delta
由兩片長度相同的冷卻柱和一組同長度的百葉窗組成三角形的冷卻單元。
2.0.7 冷卻扇段 cooling sector
由若干相鄰的冷卻三角組成的一個功能單元，稱為冷卻扇段。每個冷卻扇段由一組進水閥、出水閥、放空閥、排氣裝置等控制運行。
2.0.8 初始溫差 initial temperature difference (ITD)
間接空冷散熱器冷卻水進口溫度與散熱器入口空氣溫度的差值。
2.0.9 單流程 single flow pass
循環冷卻水從冷卻柱一端進入，不改變方向直接從冷卻柱的另一端流出。
2.0.10 雙流程 double flow pass
循環冷卻水從冷卻柱一端的半側翅片管流入，在冷卻柱另一端通過水室折返到另半側翅片管后流出，進水和出水在冷卻柱同一端，流入翅片管和流出翅片管內的水流方向相反。
2.0.11 自然通風間接空冷塔 natural draught indirect dry cooling tower
利用冷卻塔內外空氣密度差形成的空氣自然對流作用冷卻空冷散熱器內循環冷卻水的設施。
2.0.12 機械通風間接空冷塔 mechanical draught indirect dry cooling tower
利用風機形成的空氣強制對流作用冷卻空冷散熱器內循環冷卻水的設施。
2.0.13 排煙間接空冷塔 indirect dry cooling tower with flue gas discharge
兼有煙囪排放煙氣功能的自然通風間接空冷塔。
2.0.14 展寬平臺 widening platform
冷卻三角在塔周垂直布置時，冷卻三角頂部與間接空冷塔塔體之間的封閉結構。
2.0.15 設計環境風速 design ambient wind velocity
在空冷塔外零米地面以上10m標高處未擾動環境空氣的10min平均流速。
3 基本規定
3.0.1 間接空冷系統宜采用自然通風間接空冷塔，當有以下條件限制且經技術經濟比較論證，可采用機械通風間接空冷塔：
1 廠址占地受限，布置自然通風間接空冷塔有困難；
2 冬季氣溫低或供熱機組采用自然通風間接空冷塔防凍困難。
3.0.2 表面式凝汽器間接空冷系統和混合式凝汽器間接空冷系統的選擇應綜合凝汽器端差、循環冷卻水和凝結水水質控制、系統耗電量以及混合式凝汽器和調壓水輪機的設計制造水平等因素，經技術經濟比較論證確定。
3.0.3 輔機驅動用汽輪機的排汽冷卻設施宜與主機冷卻設施合并設置。
3.0.4 在最冷月平均氣溫小于或等于－10℃的地區采用間接空冷系統時，應采取特殊的防凍措施；在夏季氣溫較高地區使用時，宜采取合理的配置規模和度夏設計措施；在高環境風速地區使用時，宜采取防大風措施；在環境空氣質量較差地區，包括空氣中飄浮物或沙塵較多地區使用時，宜采用加強散熱器清洗系統的設計。
3.0.5 對于單機容量為600MW級及以上機組，每臺機組宜配置1座自然通風間接空冷塔。
3.0.6 間接空冷系統的自動化水平應與單元機組的自動化水平相一致。
3.0.7 間接空冷系統應納入單元機組分散控制系統(DCS)監視與控制。
4 間接空冷系統氣象參數選擇要求
4.0.1 間接空冷系統設計所需的氣象資料和深度應符合現行行業標準《火力發電廠水工設計基礎資料及其深度規定》DL／T 5507的有關要求。
4.0.2 間接空冷系統設計氣溫應按參證氣象站典型年的氣象資料確定，典型年的選擇應符合現行行業標準《電力工程氣象勘測技術規程》DL／T 5158的有關要求。
4.0.3 典型年氣溫累積小時數統計應按氣溫由高到低遞減順序排列，氣溫分級不宜大于2℃。典型年氣溫累積小時數統計表內容應包括各級氣溫對應出現的小時數、累計出現小時數、累積頻率等統計資料。
4.0.4 間接空冷系統環境風資料宜符合下列規定：
1 統計分析最近10年全年、各季和逐月的各風向風頻、平均風速、最大風速；
2 統計分析最近10年全年和夏季的風速大于3m／s的各風向出現次數、風頻、平均風速；
3 統計分析最近10年當環境氣溫大于或等于26.0℃，且10min平均風速大于或等于4m／s及5m／s同時出現的各風向出現次數、風頻、平均風速。
4.0.5 當廠址與氣象站海拔高度不一致時，應對環境氣溫和大氣壓力進行修正。
4.0.6 間接空冷系統設計時應分析論證所選參證氣象站對廠址的代表性，不能確切分析參證氣象站資料對廠址區域的代表性時，應在廠址區域設立空冷氣象觀測站進行對比分析。廠址空冷氣象觀測站的相關技術要求應滿足現行行業標準《電力工程氣象勘測技術規程》DL／T 5158的規定。
4.0.7 間接空冷系統設計宜收集廠址區域的逆溫分布資料，相關技術要求宜滿足現行行業標準《電力工程氣象勘測技術規程》DL／T 5158的規定。
4.0.8 間接空冷系統設計應對廠址附近的環境空氣質量進行以下分析：
1 在沙塵暴頻發地區，應對沙塵暴的頻發季節、一次沙塵暴的最長持續時間、沙塵暴強度、主導風向、最大風速等進行分析統計；
2 宜對可能影響間接空冷散熱器性能的粉塵、植物飛絮等臟污環境條件進行分析。
5 間接空冷系統總體布置
5.0.1 間接空冷塔與周圍建筑物相對位置應符合下列要求：
1 不宜布置在直接空冷平臺夏季主導風向下風側；
2 不宜布置在機械通風濕冷塔的冬季主導風向的下風側；
3 不宜布置在粉塵源的全年主導風向下風側；
4 宜遠離露天熱源，并不宜布置在露天熱源夏季主導風向下風側。
5.0.2 散熱器在塔內水平布置時，塔間凈距應按零米標高對應塔簡支柱中心之間距離計算；散熱器在塔周垂直布置時，塔間凈距應按散熱器最外緣之間距離計算。
5.0.3 相鄰間接空冷塔的塔間凈距應符合下列規定：
1 散熱器塔內水平布置的塔間凈距不宜小于4倍較大的進風口高度，且不應小于0.5倍較大的自然通風間接空冷塔塔筒支柱中心零米處直徑；
2 散熱器塔周垂直布置的塔間凈距不宜小于3倍較高的散熱器高度，且不應小于0.5倍較大的自然通風間接空冷塔塔筒支柱中心零米處直徑；
3 機械通風間接空冷塔與自然通風間接空冷塔的塔間凈距宜符合下列規定：
1)機械通風間接空冷塔和自然通風間接空冷塔散熱器垂直布置時，塔間凈距不宜小于兩塔散熱器高度之和的1.5倍；
2)機械通風間接空冷塔散熱器垂直布置、自然通風間接空冷塔散熱器水平布置時，塔間凈距不宜小于機械通風間接空冷塔散熱器高度的1.5倍與自然通風間接空冷塔進風口高度2倍之和；
3)機械通風間接空冷塔散熱器水平布置、自然通風間接空冷塔散熱器垂直布置時，塔間凈距不宜小于機械通風間接空冷塔進風口高度的2倍與自然通風間接空冷塔散熱器高度1.5倍之和；
4)機械通風間接空冷塔和自然通風間接空冷塔散熱器水平布置時，塔間凈距不宜小于兩塔進風口高度之和的2倍。
5.0.4 間接空冷塔與周圍建(構)筑物之間的最小凈距可按下式確定：
Lmin≥0.4H＋h (5.0.4)
式中：Lmin——間接空冷塔與周圍建(構)筑物之間的最小凈距(m)；
H——間接空冷塔最外圍進風面有效高度(m)；
h——間接空冷塔周圍建(構)筑物有效阻風高度(m)。
對于靠近冷卻塔的特別高大的障礙物，應通過專項研究評估其對冷卻塔熱力性能的不利影響。
5.0.5 當廠址所在地對煙囪有限高要求或經論證采用排煙間接空冷塔技術經濟更優時，經環境影響評價達標后可采用排煙間接空冷塔。
5.0.6 當兩臺機組的間接空冷塔零米標高差大于2m時，宜采用單元制。
5.0.7 間接空冷塔的位置不宜布置在循環冷卻水系統較低點。
5.0.8 不影響間接空冷塔散熱性能和安全運行的設施，可結合相關工藝系統布置及總平面布置的要求設置于間接空冷塔內。
5.0.9 當間接空冷塔內放置有防火要求的設施時，應根據現行國家標準《火力發電廠與變電站設計防火規范》GB 50229的要求設置消防通道及配套的消防設施。
5.0.10 間接空冷塔塔筒的幾何尺寸應滿足間接空冷塔的熱力性能要求，并應結合結構合理、施工方便等因素通過技術經濟比較確定。當采用雙曲線型鋼筋混凝土塔筒時，間接空冷塔塔筒的幾何尺寸宜按表5.0.10的規定取值。
表5.0.10 雙曲線型間接空冷塔塔筒殼體推薦幾何尺寸表
塔高與塔底(±0.00m)直徑的比 喉部面積與殼底面積的比 喉部高度與塔高的比 塔頂擴散角
αt 殼底子午線傾角
αD
1.00～1.50 0.40～0.60 0.75～0.85 3°～6° 14°～17°
5.0.11 自然通風排煙間接空冷塔煙道宜設在相鄰兩個冷卻扇段之間，宜與間接空冷塔大門結合設置。
5.0.12 表面式凝汽器間接空冷系統循環水泵房宜靠近間接空冷塔布置，可根據機組臺數分建或合建；混合式凝汽器間接空冷系統循環水泵組宜靠近凝汽器布置。
5.0.13 間接空冷系統宜在間接空冷塔或主設備附近設置電子設備間。
6 間接空冷系統設計參數選擇和計算
6.1 一般規定
6.1.1 間接空冷系統各設計工況應與空冷汽輪機各設計工況相對應，設計和計算參數選擇應以空冷汽輪機對應工況的參數為依據。
6.1.2 間接空冷系統的設計工況宜在設計氣溫條件下，達到空冷汽輪機最大連續出力工況背壓和出力的要求。以最大連續出力工況出力作為機組銘牌出力的空冷機組，應根據夏季計算氣溫校核夏季計算背壓和夏季出力；以現行國家標準《固定式發電用汽輪機規范》GB／T 5578確定銘牌出力的空冷機組，應在夏季計算氣溫條件下，達到空冷汽輪機銘牌出力工況背壓和出力的要求。
6.2 間接空冷系統設計參數選擇
6.2.1 設計氣溫應根據典型年的小時-干球溫度統計，宜按5℃以上年加權平均法確定設計氣溫，5℃以下按照5℃計算。
6.2.2 夏季計算氣溫應根據發電機組夏季電力負荷需求和特點合理確定，可選取典型年的小時干球溫度統計表由高至低取累計不大于200h對應的環境氣溫。
6.2.3 設計環境風速應根據廠址參證氣象站或廠址空冷氣象觀測站統計資料確定，設計環境風速不宜小于最大月平均風速。
6.2.4 設計大氣壓力和夏季大氣壓力宜根據廠址參證氣象站或廠址空冷氣象觀測站統計資料確定，設計大氣壓力宜采用多年平均大氣壓力，夏季大氣壓力宜采用多年最熱月平均大氣壓力。
6.2.5 設計相對濕度和夏季相對濕度宜根據廠址參證氣象站或廠址空冷氣象觀測站統計資料確定，設計相對濕度宜采用多年平均相對濕度，夏季相對濕度宜采用多年最熱月平均相對濕度。
6.2.6 初始溫差應根據氣象條件、主機選型、廠址布置等條件通過技術經濟比較優化計算確定。設計初始溫差值宜在25℃～35℃范圍內選擇。
6.2.7 對設有凝結水精處理系統的電廠，夏季計算背壓對應的飽和蒸汽溫度應與凝結水精處理系統陰離子交換樹脂的耐溫程度相匹配。
6.3 間接空冷系統計算
6.3.1 間接空冷系統熱力計算應符合以下規定：
1 間接空冷散熱器的換熱量應按下列公式計算：
Q1＝K×S×Ft×?tm (6.3.1-1)
(6.3.1-2)
(6.3.1-3)
t1＝ts－(TTD)c (6.3.1-4)
t2＝t1－?t (6.3.1-5)
(6.3.1-6)
式中：Q1——間接空冷散熱器換熱量(W)；
K——總傳熱系數[W／(m2·℃)]；與散熱器水側流速和空氣側風速有關，關系式由制造廠提供或通過試驗給出；
S——散熱器傳熱面積(m2)；
Ft——非逆流換熱修正系數；
△tm——傳熱平均溫差(℃)；
ma——通過散熱器的迎面質量風速[kg／(s·m2)]；
υ——散熱器水側流速(m／s)；
μ——空氣動力黏度(Pa·s)；
ts——對應于汽輪機排汽壓力的飽和蒸汽溫度(℃)；
t1——散熱器進水溫度(℃)；
t2——散熱器出水溫度(℃)；
?t——循環冷卻水進出水溫差(℃)；
θ1——散熱器入口空氣溫度，即環境干球溫度(℃)；
θ2——散熱器出口空氣溫度(℃)；
(TTD)c——凝汽器端差(℃)；
Qk——凝汽器的排熱量(W)；
W——循環冷卻水流量(kg／s)；
cpw——水的比熱容，4187[J／(kg·℃)]。
2 凝汽器的排熱量應按下式計算：
Qk＝Dk(hk－hc)＋∑Dki(hki－hci)＋Qs (6.3.1-7)
式中：Qk——凝汽器的排熱量(W)；
Dk——主機汽輪機的排汽量(kg／s)；
hk——主機汽輪機的排汽焓(J／kg)；
hc——主機凝結水的烤(J／kg)；
Dki——各輔機汽輪機的排汽量(kg／s)；
hki——各輔機汽輪機的排汽焓(J／kg)；
hci——各輔機凝結水的焓(J／kg)；
Qs——疏水的排熱量(W)。
3 環境空氣的吸熱量應按下式計算：
Q2＝?θ×ma×Sn×Cpa (6.3.1-8)
式中：Q2——環境空氣的吸熱量(W)；
?θ——空氣溫升(℃)；
Sn——散熱器的迎風面面積(m2)；
cpa——空氣定壓比熱容[J／(kg·℃)]。
6.3.2 自然通風間接空冷塔風筒有效高度產生的抽力宜按下式計算：
ND＝He×g×(ρ1－ρ2) (6.3.2)
式中：ND——間接空冷塔的風筒有效高度產生的抽力(Pa)；
He——間接空冷塔的有效抽風高度(m)；散熱器垂直布置時宜采用散熱器中部至塔頂的高差，散熱器水平布置時宜采用散熱器頂部的平均值至塔頂的高差；
g——重力加速度(m／s2)；
ρ1——間接空冷塔外冷空氣密度(kg／m3)；
ρ2——間接空冷塔內熱空氣密度(kg／m3)。
6.3.3 自然通風間接空冷塔各部位通風阻力計算宜符合下列要求：
1 采用與所設計的間接空冷塔相同或相似的原型塔的實測數據；
2 當缺乏上述數據時，可按本規范第6.3.4條和第6.3.5條規定的經驗方法計算。
6.3.4 自然通風間接空冷塔通風阻力可按下列經驗方法計算：
1 百葉窗通風阻力可按下式計算：
(6.3.4-1)
式中：?Pb——百葉窗通風阻力(Pa)；
Cb——系數，通過試驗獲得；
m——指數，通過試驗獲得；
υb——氣流通過百葉窗的迎面風速(m／s)。
2 散熱器進口阻力可按下列公式計算：
(6.3.4-2)
Khi＝51.601－1.335α＋0.0094α2 (6.3.4-3)
式中：?Phi——散熱器進口的阻力(Pa)；
Khi——散熱器三角形進口阻力系數；
υh——通過散熱器迎風面空氣流速(m／s)；
α——冷卻三角頂角(o)，40o≤α≤70o。
3 散熱器出口阻力可按下列公式計算：
(6.3.4-4)
Kho＝14.015－0.2929α＋0.0017α2 (6.3.4-5)
式中：?Pho——散熱器出口阻力(Pa)；
Kho——散熱器三角形出口阻力系數。
4 散熱器阻力可按下式計算：
(6.3.4-6)
式中：?Ph——氣流通過散熱器的阻力(Pa)；
Ch——系數，通過試驗獲得；
n——指數，通過試驗獲得。
5 氣流通過塔筒支柱阻力可按下列公式計算：
(6.3.4-7)
(6.3.4-8)
(6.3.4-9)
式中：?Pd——氣流經過塔筒支柱阻力(Pa)；
Cd——塔筒支柱阻力系數；Cd可按表6.3.4-1的規定取值；
ρ——通過斷面氣流的密度(kg／m3)；
υd——塔筒支柱上游迎面風速(m／s)；
Ad——進風口柱體總橫斷面積(m2)；
A——進風口總面積(m2)；
b——塔筒支柱平行于空氣流動方向的寬度(m)；
d——塔筒支柱迎空氣流動方向的寬度(m)；
Re——雷諾數(103＜Re＜106)；
μ——通過塔筒支柱氣流動力黏度(Pa·s)。
表6.3.4-1 塔筒支柱阻力系數的取值和適用范圍表
支柱截面形式 塔筒支柱阻力系數Cd 適用范圍
類似于橢圓形 按本標準式(6.3.4-8)計算 103＜Re＜106
圓形 1.2 104＜Re＜2×105
矩形 2 104＜Re＜2×105
6 自然通風間接空冷塔進風口至風筒底部截面之間阻力可按下列公式計算：
(6.3.4-11)
(6.3.4-11)
(6.3.4-12)
式中：?Pi——空冷塔空氣進口轉彎向上及收縮阻力(Pa)；
Ki——空冷塔進口轉彎向上及收縮阻力系數，可按表6.3.4-2的規定計算；
υe——進風口上緣風筒橫截面平均空氣流速(m／s)；
Di——進風口上緣塔筒直徑(m)；
Hi——進風口高度(m)；
Sc——間接空冷塔有效利用系數，可近似為散熱器沿塔周邊的有效長度與塔周邊長度之比。
表6.3.4-2 空冷塔進口轉彎向上及收縮阻力系數計算公式和適用范圍表
散熱器布置形式 空冷塔進口轉彎向上及收縮阻力系數Ki計算公式 適用范圍
散熱器水平布置 按本標準式(6.3.4-11)計算 ，
0.4≤Sc≤1，
19≤Ch≤50
散熱器垂直布置 按本標準式(6.3.4-12)計算 ，
5≤Ch≤40
7 間接空冷塔出口阻力可按下式計算：
(6.3.4-13)
式中：?Po——空冷塔出口阻力(Pa)；
υo——間接空冷塔出口空氣流速(m／s)；
ρo——間接空冷塔出口熱空氣密度(kg／m3)。
8 空氣通過自然通風間接空冷塔總阻力可按下式計算：
TPz＝?Pb＋?Phi＋?Pho＋?Ph＋?Pd＋?Pi＋?Po (6.3.4-14)
式中：TPz——空氣通過自然通風間接空冷塔總阻力(Pa)。
6.3.5 機械通風間接空冷塔通風阻力可按下列經驗方法進行計算：
1 機械通風間接空冷塔進風口阻力可按下式計算：
(6.3.5-1)
式中：?Pdj——機械通風間接空冷塔進風口阻力(Pa)；
υdj——機械通風間接空冷塔進風口斷面的空氣流速(m／s)。
2 機械通風間接空冷塔氣流轉彎阻力可按下式計算：
(6.3.5-2)
式中：?Pz——機械通風間接空冷塔氣流轉彎阻力(Pa)；
Kz——氣流轉彎阻力系數，可取0.5。
3 支撐梁阻力可按下列公式計算：
(6.3.5-3)
(6.3.5-4)
式中：?P1——支撐梁阻力(Pa)；
K1——支撐梁阻力系數；
υ1——通過支撐梁處的空氣流速(m／s)；
A1——支撐梁處氣流有效面積(m2)；
A0——塔體圍護橫截面積(m2)。
4 風筒圈梁進口阻力可按下式計算：
(6.3.5-5)
式中：?Pq——風筒圈梁進口阻力(Pa)；
Kq——風筒圈梁進口阻力系數，可按本規范附錄A.0.1的規定取值；
υq——風筒圈梁進口斷面的空氣流速(m／s)；
ε0——風筒圈梁進口面積比阻力修正系數，可按本規范附錄A.0.2的規定取值。
5 風筒進口漸縮段阻力可按下列公式計算：
(6.3.5-6)
(6.3.5-7)
(6.3.5-8)
式中：?Pc——風筒漸縮段阻力(Pa)；
Kc——風筒漸縮段阻力系數；
υf——風筒喉部截面積的空氣流速(m／s)；
C——風筒進口逐漸縮小緩沖系數，可按本規范附錄A.0.3的規定取值；
Af——風筒喉部截面積(m2)；
Ac——風筒漸縮段進口截面積(m2)；
ε——風筒進口漸縮段面積比阻力修正系數；
λ——摩擦系數，可采用0.03；
γ——風筒進口漸縮角(o)。
6 風筒出口擴散段阻力可按下列公式計算：
(6.3.5-9)
Ks＝(Ks1＋Ks2)×(1＋δ) (6.3.5-10)
(6.3.5-11)
(6.3.5-12)
式中：?Ps——風筒出口擴散段阻力(Pa)；
Ks——風筒出口擴散段阻力系數；
Ks1——風筒擴散段阻力系數；
Ks2——風筒出口動能損失阻力系數；
δ——風筒內裝風機造成風速分布不均勻的修正系數，可按本規范附錄A.0.4的規定取值；
C＇——逐漸擴大緩沖系數，可按本規范附錄A.0.5的規定取值；
As——風筒出口截面積(m2)；
γ＇——風筒出口漸擴角(o)。
7 空氣通過抽風式機械通風間接空冷塔總阻力可按下式計算：
TPj＝?Pb＋?Phi＋?Pho＋?Ph＋?Pdj＋?Pz＋?P1＋?Pq＋?Pc＋?Ps (6.3.5-13)
式中：TPj——空氣通過機械通風間接空冷塔總阻力(Pa)。
6.3.6 間接空冷散熱器的水力計算宜采用與所設計的散熱器相同的實測數據或與所設計的散熱器相似的實測數據；當缺乏上述數據時，可按下列經驗方法計算圓形管束間接空冷散熱器水阻：
1 冷卻管束內的水阻可按下式計算：
(6.3.6-1)
式中：RG——冷卻管束的水阻(mH2O)；
υw——冷卻管束內平均流速(m／s)；
d2——冷卻管束內徑(mm)；
R1——水溫修正系數，可按本標準附錄B.0.1的規定取值；
Li——全流程冷卻管束總長度(m)。
2 冷卻管束流入、流出管端水阻可按本規范附錄B.0.2的規定取值，對應的流速為冷卻管束內平均流速。
3 水室進口水阻和出口水阻可按本規范附錄B.0.2的規定取值，對應的流速為與水室相接的循環冷卻水進水管和出水管的流速。
4 間接空冷散熱器總水阻可按下式計算：
RT＝RG＋RDi＋RDo＋RSi＋RSo (6.3.6-2)
式中：RT——間接空冷散熱器總水阻(mH2O)；
RDi——冷卻管束流入管端水阻(mH2O)；
RDo——管端流入冷卻管束水阻(mH2O)；
RSi——水室入口水阻(mH2O)；
RSo——水室出口水阻(mH2O)。
6.3.7 間接空冷系統優化計算應符合下列規定：
1 間接空冷系統的優化計算應根據典型年小時氣溫條件，結合不同末級葉片的汽輪機特性和系統布置，確定最佳的汽輪機背壓、凝汽器的型式和面積、空冷散熱器型式和面積、冷卻水量、循環水泵參數、循環水管管徑及空冷塔的塔型等；
2 間接空冷系統的優化計算應按下列兩階段進行：
1) 在工程可行性研究階段應進行初步優化，確定設計氣溫，優化間接空冷系統初始溫差，確定汽輪機設計背壓、空冷系統配置、凝汽器型式和面積；
2) 在工程初步設計階段，應根據確定的空冷汽輪機特性、空冷設備特性和氣象條件等因素進一步對空冷系統設計參數進行優化，確定合理的冷卻水量、空冷散熱器面積、空冷塔的塔型、主要循環水管管徑及經濟配置等。
3 間接空冷系統的優化計算宜根據工程具體條件，主要優化參數宜包含如下內容：
1) 冷卻水量；
2) 凝汽器的換熱面積、流程數、殼體與背壓個數，凝汽器內冷卻水管的管徑、壁厚、根數和長度等；
3) 循環水泵的臺數、運行方式；
4) 主要循環水管管徑；
5) 空冷散熱器型式、冷卻三角頂角、高度和數量，空冷散熱器面積；
6) 自然通風間接空冷塔零米直徑、高度、出口直徑、喉部直徑等主要塔型參數；機械通風間接空冷塔的迎風面風速、單元數、軸流風機規格及所配電動機的規格、臺數。
4 在滿足熱力性能和總平面布置要求的前提下，間接空冷塔的塔型宜滿足本規范5.0.10條的規定；
5 循環水量可通過循環水泵的最佳運行臺數進行選擇，運行循環水量占總循環水量的百分數可按表6.3.7的規定選取；
表6.3.7 運行循環水量百分數
循環水泵臺數 水量百分數(%)
運行1臺 運行2臺 運行3臺 運行4臺
2 60～65 100 — —
3 40～45 75～80 100 —
4 30～35 60～65 85～90 100
6 循環水管的流速范圍宜按現行行業標準《火力發電廠水工設計規范》DL／T 5339的規定選取。
6.3.8 間接空冷系統優化計算宜采用年費用最小法，計算方法應符合現行行業標準《火力發電廠水工設計規范》DL／T 5339的規定。
6.3.9 水錘計算宜符合現行行業標準《火力發電廠水工設計規范》DL／T 5339的規定。
6.4 間接空冷系統設計裕量
6.4.1 散熱器制造廠應提供間接空冷散熱器管束傳熱系數，并宜同時提供試驗室試驗報告和冷卻元件性能試驗報告，必要時可提供工程應用測試報告。由試驗室試驗所得的傳熱系數，在實際工程應用計算時宜按乘以0.80～0.85的折減系數計算。
6.4.2 間接空冷系統宜留有適當的設計裕量，設計工況的冷卻塔出水溫度裕量宜為0.5℃～1.5℃，夏季計算工況的冷卻塔出水溫度裕量宜為1℃～3℃，以現行國家標準《固定式發電用汽輪機規范》GB／T 5578確定銘牌出力時，夏季冷卻塔出水溫度裕量宜取高值。
7 間接空冷工藝系統及設備
7.1 間接空冷散熱器系統
7.1.1 間接空冷散熱器宜采用塔周垂直布置，在沙塵暴頻發地區散熱器可采用塔內水平布置。
7.1.2 散熱器型式應根據熱負荷需求和環境條件等因素進行選擇，宜選擇傳熱效率高、空氣阻力小、水力特性好、性能先進和強度能滿足安裝、運行、維修、清洗要求等的散熱器。非釬焊式鋁制管束的設計應符合現行行業標準《火力發電廠鋁制間接空冷管束》DL/T 1672的有關要求。
7.1.3 散熱器的流程形式、冷卻柱長度或高度、冷卻三角數量選擇應結合熱負荷需求、氣象條件、防凍要求、散熱器材質、總平面布置等因素，經技術經濟比較論證確定，并宜符合下列規定：
1 鋼制管束內水流速度宜為0.7m/s～2.0m/s，鋁制管束內水流速度宜為0.7m/s～1.8m/s；
2 冷卻柱的水阻不宜大于8m水柱；
3 鋼質散熱器的冷卻柱長度或高度不宜大于15m；
4 鋁制散熱器的冷卻柱高度宜選擇散熱器本體及其框架的制造成熟可靠的方案；
5 散熱器三角數量和冷卻柱高度的組合宜使自然通風間接空冷塔塔型符合本標準第5.0.10條的規定。
7.1.4 自然通風間接空冷塔的散熱器迎面風速應綜合環境風速、冷卻水量、間接空冷塔塔型、間接空冷塔高度、空冷系統配置等因素，宜在1.0m/s～2.3m/s范圍內選擇；機械通風間接空冷塔的散熱器迎面風速應綜合環境風速、噪聲要求、空冷系統配置、電動機電壓等級等因素，迎面風速宜在1.5m/s～2.5m/s范圍內選擇。
