阅读说明：本技术 一种槽式太阳能集热系统性能测试方法 (Performance test method for groove type solar heat collection system ) 是由 张子楠 董军 张亚南 于 2020-05-22 设计创作，主要内容包括：本发明涉及一种槽式太阳能集热系统性能测试方法,属于槽式太阳能发电的技术领域；其包括步骤：(1)流量设置到稳定状态后开始测试,连续测量进出口温度、流量、压力、法向直接辐照量、温度、湿度、风力参数；(2)计算导热介质热物性；(3)计算集热功率；(4)计算效率；(5)分析集热功率不确定度；(6)分析集热效率不确定度；(7)数据汇总整理得出结果。本发明具有方便对槽式集热系统性能进行检测,有助于槽式太阳能热发电站集热系统性能评价及验收。(The invention relates to a performance test method of a trough type solar heat collection system, belonging to the technical field of trough type solar power generation; which comprises the following steps: (1) testing is started after the flow is set to a stable state, and the temperature, the flow, the pressure, the normal direct irradiation quantity, the temperature, the humidity and the wind power parameters of an inlet and an outlet are continuously measured; (2) calculating the thermophysical property of the heat-conducting medium; (3) calculating heat collection power; (4) calculating efficiency; (5) analyzing uncertainty of heat collection power; (6) analyzing uncertainty of heat collection efficiency; (7) and summarizing and sorting the data to obtain a result. The invention is convenient to detect the performance of the trough type heat collecting system and is beneficial to the performance evaluation and acceptance of the trough type solar thermal power station heat collecting system.)

1. A performance test method for a trough type solar heat collection system is characterized by comprising the following steps: the method comprises the following steps:

(1) testing is started after the flow is set to a stable state, and the temperature, the flow, the pressure, the normal direct irradiation quantity, the temperature, the humidity and the wind power parameters of an inlet and an outlet are continuously measured;

(2) calculating the thermophysical property of the heat-conducting medium;

(3) calculating heat collection power;

(4) calculating efficiency;

(5) analyzing uncertainty of heat collection power;

(6) analyzing uncertainty of heat collection efficiency;

(7) and summarizing and sorting the data to obtain a result.

2. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: step (0) of pre-experiment preparation is further arranged before the step (1), the pre-experiment preparation comprises confirming an experiment precondition before starting an experiment, and the experiment precondition comprises the following three aspects;

firstly, determining that a relevant test of a heat collection system of a trough type solar photo-thermal power station needs to be carried out after the power station normally operates;

② ensure that the maximum value of normal direct irradiance during the test is more than 600W/m²；

And thirdly, setting the flow and the temperature of the heat-conducting medium of the heat collector to limit, and determining the safe operation allowable range of the heat collector with the flow and the temperature of the heat-conducting medium.

3. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the preparation before the experiment in the step (0) further comprises the step of ensuring that the operation time of the heat collection system is more than 4 times of a system time constant Ts and more than 15 minutes before starting the test, wherein the system time constant Ts is defined as the time required by the outlet temperature to reach 63.2% of the total temperature rise.

4. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the step (0) of preparing before the experiment further comprises the step of selecting the experiment time between 9 am and 3 pm of the real solar time, wherein each experiment time is more than 10 minutes.

5. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: setting the acquisition time interval parameters of each parameter in the step (1) as follows:

the mass flow, pressure and temperature of the heat-conducting medium are less than or equal to 10 s;

the ambient wind speed, wind direction, temperature and humidity are less than or equal to 1 min;

the normal direct irradiation amount of the sunlight is less than or equal to 10 s.

6. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the calculation of the thermal physical property of the heat-conducting medium in the step (2) comprises the following two aspects of calculation:

calculating the density of the heat-conducting medium:

ρ＝a+bT+cT²+dT³·······················(1)

calculating the specific heat of the heat-conducting medium:

c_p＝e+fT+gT²·······················(2)。

7. the method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the heat collection power calculation in the step (3) adopts the following formula;

wherein: p is heat power of a heat collection field, kW;

-mass flow rate of heat transfer medium (HTF), kg/s;

c_p，outthe specific heat capacity at constant pressure of the heat-conducting medium outlet is kJ/(kg. K);

c_p，inthe heat-conducting medium inlet constant pressure specific heat capacity, kJ/(kg. K);

T_out-heat transfer medium outlet temperature, K;

T_in-heat transfer medium inlet temperature, K.

8. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the efficiency calculation in the step (4) adopts the following formula:

wherein:

eta-thermal efficiency,%;

θ — average solar incident angle during the test, unit: (iv) DEG;

a-area of collecting opening of heat collecting field in tracking mode in test process, m²The light collecting port of the heat collectorLength and width product;

ANI-vertical irradiation of a daylight opening;

DNI-Normal direct irradiation;

wherein ANI ═ DNI cos θ.

9. The method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the uncertainty analysis of the heat collection power in the step (5) is calculated by adopting the following formula;

10. the method for testing the performance of the trough type solar heat collection system according to claim 1, wherein the method comprises the following steps: the uncertainty analysis of the heat collection efficiency in the step (6) is calculated by adopting the following formula;

Technical Field

The invention relates to the technical field of trough type solar power generation, in particular to a method for testing the performance of a trough type solar heat collection system.

Background

The trough type solar thermal power generation system is totally called as a trough type parabolic reflector solar thermal power generation system, and is characterized in that a plurality of trough type parabolic concentrating collectors are arranged in series and parallel to heat a working medium to generate high-temperature steam to drive a steam turbine generator set to generate power; the groove type solar thermal power generation system generally adopts heat conduction oil as a heat conduction medium, adopts fused salt as a heat storage medium and adopts water vapor as a power generation medium; the trough collector is a precise optical device working in a severe environment in the field.

Due to the fact that the photo-thermal power generation is in the initial development stage in China, the construction and the power station performance test of the trough type solar thermal power generation heat collector are inexperienced in China, and therefore a blank exists for the performance test of the trough type solar thermal power collection system.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for testing the performance of a trough type solar heat collection system.

The above object of the present invention is achieved by the following technical solutions:

a performance test method for a trough type solar heat collection system comprises the following steps:

(1) testing is started after the flow is set to a stable state, and the temperature, the flow, the pressure, the normal direct irradiation quantity, the temperature, the humidity and the wind power parameters of an inlet and an outlet are continuously measured;

(2) calculating the thermophysical property of the heat-conducting medium;

(3) calculating heat collection power;

(4) calculating efficiency;

(5) analyzing uncertainty of heat collection power;

(6) analyzing uncertainty of heat collection efficiency;

(7) and summarizing and sorting the data to obtain a result.

By adopting the technical scheme, through the cooperation of the steps, each data in the heat collection system can be measured, then each data is calculated, and finally, the measured and calculated data are sorted, so that the performance of the heat collection system can be tested, the result of whether the heat collection system can adapt to the severe environment stable operation is obtained, and then whether the design requirements of the groove type photo-thermal power station are met is judged, and the efficient and stable operation of the groove type photo-thermal power station is ensured.

The present invention in a preferred example may be further configured to: step (0) of pre-experiment preparation is further arranged before the step (1), the pre-experiment preparation comprises confirming an experiment precondition before starting an experiment, and the experiment precondition comprises the following three aspects;

firstly, determining that a relevant test of a heat collection system of a trough type solar photo-thermal power station needs to be carried out after the power station normally operates;

ensuring that the maximum value of normal direct irradiance is more than 600W/m2 during the test;

and thirdly, setting the flow and the temperature of the heat-conducting medium of the heat collector to limit, and determining the safe operation allowable range of the heat collector with the flow and the temperature of the heat-conducting medium.

By adopting the technical scheme, the heat collection system can be in a hypothetical working state through the early-stage preparation of the experiment in three aspects, so that the performance of the heat collection system can be better tested, the test result is more accurate, and the influence of unexpected factors on the performance test is reduced.

The present invention in a preferred example may be further configured to: the preparation before the experiment in the step (0) further comprises the step of ensuring that the operation time of the heat collection system is more than 4 times of a system time constant Ts and more than 15 minutes before starting the test, wherein the system time constant Ts is defined as the time required by the outlet temperature to reach 63.2% of the total temperature rise.

By adopting the technical scheme, the heat collection system is in a load working state, and the test result of the heat collection system can be more accurate.

The present invention in a preferred example may be further configured to: the step (0) of preparing before the experiment further comprises the step of selecting the experiment time between 9 am and 3 pm of the real solar time, wherein each experiment time is more than 10 minutes.

By adopting the technical scheme, when the sun is not shielded in the sky, the solar illumination intensity from 9 points to 3 points is the strongest time period in one day, so that the heat collection system can be tested under the condition of approaching the limit, the test time is longer than 10 minutes, and the test result is more accurate.

The present invention in a preferred example may be further configured to: setting the acquisition time interval parameters of each parameter in the step (1) as follows:

the mass flow, pressure and temperature of the heat-conducting medium are less than or equal to 10 s;

the ambient wind speed, wind direction, temperature and humidity are less than or equal to 1 min;

the normal direct irradiation amount of the sunlight is less than or equal to 10 s.

By adopting the technical scheme, the measured data can be more objective as far as possible, so that the occurrence of special conditions is reduced, and the accuracy of the heat collection performance test is improved.

The present invention in a preferred example may be further configured to: the calculation of the thermal physical property of the heat-conducting medium in the step (2) comprises the following two aspects of calculation:

calculating the density of the heat-conducting medium:

ρ＝a+bT+cT²+dT³·······················(1)

calculating the specific heat of the heat-conducting medium:

c_p＝e+fT+gT²·······················(2)。

the present invention in a preferred example may be further configured to: the heat collection power calculation in the step (3) adopts the following formula;

wherein: p is heat power of a heat collection field, kW;

-mass flow rate of heat transfer medium (HTF), kg/s;

c_p，outthe specific heat capacity at constant pressure of the heat-conducting medium outlet is kJ/(kg. K);

c_p，inthe heat-conducting medium inlet constant pressure specific heat capacity, kJ/(kg. K);

T_out-heat transfer medium outlet temperature, K;

T_in-heat transfer medium inlet temperature, K.

The present invention in a preferred example may be further configured to: the efficiency calculation in the step (4) adopts the following formula:

wherein:

eta-thermal efficiency,%;

θ — average solar incident angle during the test, unit: (iv) DEG;

a-area of collecting opening of heat collecting field in tracking mode in test process, m²The product of the length and the width of a lighting port of the heat collector is obtained;

ANI-vertical irradiation of a daylight opening;

DNI-Normal direct irradiation;

wherein ANI ═ DNI cos θ.

The present invention in a preferred example may be further configured to: the uncertainty analysis of the heat collection power in the step (5) is calculated by adopting the following formula;

the present invention in a preferred example may be further configured to: the uncertainty analysis of the heat collection efficiency in the step (6) is calculated by adopting the following formula;

in summary, the invention includes at least one of the following beneficial technical effects:

1. through the steps 1-7, all parameters in the heat collection system can be measured, and finally, the measured results are summarized, sorted and calculated, so that the performance of the current heat collection system can be obtained, the purpose of testing the performance of the heat collection system is achieved, and the performance acceptance of the heat collection system of the slot type photo-thermal power station and the stable operation of the power station are facilitated;

2. the data obtained by the side can be calculated through the calculation formulas 1-6, so that the values of density of the heat-conducting medium, specific heat of the heat-conducting medium, power of a heat collection field, efficiency, uncertain heat collection power and uncertain heat collection efficiency can be obtained, the performance of the heat collection system can be judged, and a final test result can be obtained.

Drawings

Fig. 1 is a schematic diagram of inlet and outlet temperature and flow measurement points in an embodiment.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The present invention will be described in further detail with reference to the accompanying drawings.

The invention discloses a method for testing the performance of a slot type solar heat collection system, which comprises the following steps:

(0) preparing before experiment;

(1) testing is started after the flow is set to a stable state, and the temperature, the flow, the pressure, the normal direct irradiation quantity, the temperature, the humidity and the wind power parameters of an inlet and an outlet are continuously measured;

(2) calculating the thermophysical property of the heat-conducting medium;

(3) calculating heat collection power;

(4) calculating efficiency;

(5) analyzing uncertainty of heat collection power;

(6) analyzing uncertainty of heat collection efficiency;

(7) and summarizing and sorting the data to obtain a result.

All parameters in the heat collecting system can be collected through the steps, and the collected parameters are sorted and compared, so that the performance of the heat collecting system can be evaluated, whether the heat collecting system has problems or not is judged, the engineering acceptance of the heat collecting system of the groove type photo-thermal power station is facilitated, and the efficient and stable operation of the groove type photo-thermal power station is ensured.

Step (0) the preparation before the experiment comprises experiment precondition which comprises the following three aspects:

firstly, relevant tests of a heat collecting system of a trough type solar photo-thermal power station need to be carried out after the power station normally operates.

② Normal direct irradiance during testingMaximum value is not less than 600W/m²。

And thirdly, the flow and the temperature of the heat-conducting medium of the heat collector cannot exceed the safe operation allowable range of the heat collector during the test.

Through the preparation work of above three steps, can make the system be in the state of normal work, and then can reduce the influence that unexpected factor caused the test result to can carry out accurate rapid detection to heating system's performance, conveniently test heat collector construction and power station performance, conveniently assess the performance, and then help the acceptance of slot type light and heat power station heating system engineering, guarantee the high-efficient stable operation of slot type light and heat power station.

The preparation before the experiment in the step (0) also comprises the step of ensuring that the running time of the heat collection system is greater than 4 times of the system time constant Ts before the test is started; because of the inertia of the heat collecting system, the heat collecting system is required to ensure that the running time of the heat collecting system is greater than 4 times of the system time constant Ts, the running time of the heat collecting system is not less than 15 minutes, and the system time constant Ts is defined as the time required by the outlet temperature to reach 63.2% of the total temperature rise. Meanwhile, the test time is selected between 9 am and 3 pm of the real solar time; the sunlight irradiation intensity in the time period is maximum, the heat collecting system can work under the maximum load as much as possible, the accuracy of performance detection can be further improved, the test time is more than 10 minutes each time, the performance in different time periods can be detected, and the accuracy of performance detection is further improved.

Referring to fig. 1, in step (1), after the flow is set to a stable state, testing is started, and environmental parameters of inlet and outlet temperature, flow, pressure, normal direct irradiation amount, temperature, humidity and wind power are continuously measured; the acquisition time interval of each parameter on the inlet and outlet pipeline of the heat collection system meets the requirements of table 1.

TABLE 1 parameter measurement time intervals

Measurement object	Measuring time intervals
		Mass flow, pressure and temperature of heat-conducting medium	≤10s
Ambient wind speed, direction, temperature, humidity	≤1min
		DNI	≤10s
Reflectivity of the mirror	Before and after the test, the measurement is carried out

Wherein, DNI-normal direct irradiation.

The step (2) of calculating the thermophysical property of the heat-conducting medium comprises the following two aspects:

calculating the density of the heat-conducting medium:

ρ＝a+bT+cT²+dT³·····················(1)

calculating the specific heat of the heat-conducting medium:

c_p＝e+fT+gT²······················(2)

and the values of a, b, c, d, e, f and g in the formula are determined according to different heat-conducting medium characteristics.

Calculating the heat collection power by adopting the following formula:

wherein: p is heat power of a heat collection field, kW;

-mass flow rate of heat transfer medium (HTF), kg/s;

c_p，outthe specific heat capacity at constant pressure of the heat-conducting medium outlet is kJ/(kg. K);

c_p，inthe heat-conducting medium inlet constant pressure specific heat capacity, kJ/(kg. K);

T_out-heat transfer medium outlet temperature, K;

T_in-heat transfer medium inlet temperature, K.

The calculation efficiency of the step (4) is calculated by adopting the following formula,

wherein:

eta-thermal efficiency,%;

θ — average solar incident angle during the test, unit: (iv) DEG;

a-area of collecting opening of heat collecting field in tracking mode in test process, m²The product of the length and the width of a lighting port of the heat collector is obtained;

ANI-vertical irradiation of a daylight opening;

wherein ANI ═ DNI cos θ.

Analyzing the uncertainty of the heat collection power by adopting the following formula:

and (6) analyzing the uncertainty of the heat collection efficiency by adopting the following formula:

and (7) summarizing and sorting the data to obtain a result, wherein in the test result processing process, the allowable fluctuation range of the measurement parameters is shown in the table 2, and if the measured data is abnormal, the measured data is corrected or discarded.

TABLE 2 allowable fluctuation range of operating parameters during thermal field test

Wherein: ANI-vertical irradiation of a daylight opening; wherein ANI ═ DNI cos θ.

And finally, calculating each data according to the collected data and parameters and formulas (1), (2), (3), (4), (5) and (6) to obtain a final test result, judging the performance of the groove type heat collection system and further judging the delivery of the groove type photo-thermal power station.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.