WO2011124720A2 - Clouds managing system for a solar field, method for operating the clouds management system and solar field with the clouds managing system - Google Patents

Abstract

The invention relates to a clouds managing system for a solar field with a plurality of solar collectors is provided, wherein the clouds managing system comprises: A plurality of sensor units for detecting a current cloud position of a cloud and/or a current cloud movement of the cloud, wherein the sensor units are distributed across the solar field and/or distributed across a surrounding area of the solar field; and a cloud management module for collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, wherein the cloud management-module is designed such, that based on the cloud data a probable cloud movement of the cloud can be predicted. Preferably the cloud management module is designed such, that a mode of operation of at least one of the plurality of the solar collectors can be adjusted as a function of the cloud data. Additionally a method for operating the clouds managing system with following steps is provided: a) Detecting the current cloud position and/or detecting the current cloud movement of a cloud by the sensor units and collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, by the cloud management-module; and b) Predicting a probable cloud movement, of the cloud by the cloud management module based on the cloud data.

Description

Description

CLOUDS MANAGING SYSTEM FOR A SOLAR FIELD, METHOD FOR OPERATING THE CLOUDS MANAGEMENT SYSTEM AND SOLAR FIELD WITH THE CLOUDS MANAGING SYSTEM

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a clouds managing system for a solar field with a plurality of solar collectors,, a method for operating the clouds managing system and a solar field with the clouds managing system.

2. Description of the Related Art

A solar field comprises a plurality of solar collectors for collecting the solar radiation (sunlight) in order to convert the collected solar radiation into a usable kind of energy. For instance, by collected solar radiation a heat transfer fluid (e.g. a thermo-oil or an inorganic salt) is heated up for steam generation. The steam is used to drive a turbine for generating electrical energy.

Clouds are blocking the solar radiation. Due to the blocking less solar radiation can reach the solar collectors. This leads to a decrease of the amount of solar radiation, which can be converted into the utiiizable kind of energy.

SUMMARY OF THE INVENTION It is an object of the invention to provide a possibility of an efficient clouds management system for a solar field, which considers the influence of clouds to the operating a solar field.

This object is achieved by the invention specified in the claims.

A clouds managing system for a solar field with a plurality of solar collectors is provided, wherein the clouds managing system comprises : A plurality of sensor units for detecting; a current- cloud position of a cloud and/or a current cloud movement of the cloud,, wherein the sensor units are distributed across the solar field and/or distributed across a surrounding area of the solar field; and a cloud management module for collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, wherein the cloud management module is designed such, that based on the cloud data a probable cloud movement of the cloud can be predicted.

Preferably the cloud management module is designed such, that a mode of operation of at least one of the plurality of the solar collectors can be adjusted as a function of the cloud data.

Additionally a method for operating the clouds managing system with following steps is provided:

a} Detecting the current cloud position and/or detecting the current cloud movement of a cloud by the sensor units and collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, by the cloud management module; and

b) Predicting a probable cloud movement of the cloud by the cloud management module based on the cloud data. The method comprise preferably following additional step: Adjusting a mode of operation of at least one of the solar collectors as a function of the cloud data.

Moreover a solar field with a clouds managing system is provided. The sensor units are preferably constantly online (by day} . This means, that the sensor units are collecting the cloud data at every given moment ,

Cloud movement implies a direction of the movement as well as a speed of the movement.

The solar field can be referred as a wide network of hundreds of solar collectors spread over a wide area of the solar field linked one to the other.

A solar field operation is managed and controlled by a central control system. The clouds managing system is a part of the central control system. By the clouds managing system a following and predicting of any major changes and fluctuations in solar radiation due to clouds is possible.

One of the major factors impacting a performance of the solar field is cloudiness. This is especially important in cases where the solar field is large and clouds are randomly spread over it . Clouds coverage area has a dynamic behavior, it moves, changes, accumulates, disperses and becomes thicker or thinner at every given moment. As of today, an operator of the solar field cannot tell which areas of the solar field are shaded by clouds. There are indications for the shadowing effects, e.g. a temperature drop at those areas. But such an indication is usually delayed and time consuming,, and when discovered it is too late for any effective correction action. By the clouds managing system the detecting of the changes connected to clouds is implemented, which may affect the solar field. The clouds managing system uses these changes for an improvement of the performance of the solar field and accordingly for an improvement of the performance of the complete solar plant.

In a preferred embodiment at least one of the plurality of sensor units is usable for a sun tracking. This sensor unit has two functions: The detecting the cloud movement and the sun tracking. Additional devices are not necessary. The clouds managing system uses the radiation sensing system, which is built in the solar field. The sensing system is normally used to perform a tracking of the solar collector after the sun motion.

There are various techniques for the detecting the cloud movement possible. Preferably at least one of the plurality of sensor units comprises a cloud imaging device .

The cloud managing system combines: A suitable analyzing software (via the cloud management module) , a sun sensing system

(plurality of sensor units) and a performance model software.

On cloudy days the cloud managing system is managing the power station operation of the soiar field. This takes place in real time and fast. The cloud managing system enables a quick response to a cloud tracking. The cloud tracking is used for forecasting the direction of movement of the cloud. By this it is possible to control and manage the solar power station of the solar field immediately from the moment when a coverage by a cloud is detected and before a coverage effect takes place. The coverage effect comprises for instance an interruption of the solar power station . The cloud managing system, in event of clouds, assists to determine optimized turbine loads, timing to perform turbine shutdowns / startups,, optimized flow rate of each solar loop and overall flow of a complete solar power plant. By this a performance of the solar power plant is improved.

Summarized the clouds managing system imply following advantages for a solar field:

- Unnecessary turbine's shutdowns can be avoided.

Heat loss due to circulation of hot heat transfer fluid through shaded loops can be avoided.

Temperatures fluctuations of the heat transfer fluid are reduced .

- Thermal stress due to coverage by a cloud can be reduced.

Continuous operation of the solar power station is possible.

The reliability of the complete solar power plant and its coiaponents is increased .

The clouds managing system reduces the maintenance operation and hence the costs for operating solar power plant.

The energy output of the solar field is increased.

BIEF DESCRIPTION OF THE DRAWING

The Figure shows a solar field with a plurality of solar collectors and with a plurality of sensor units. DETAILED DESCRIPTION OF THE INVENTION

A clouds managing system for a solar field 100 with a plurality of solar collectors 102 is provided. The clouds managing system comprises: A plurality of sensor units 101 for detecting a current- cloud position 201 of a cloud 200 and/or a current cloud movement 202 of the cloud 200, wherein the sensor units 101 are distributed across the solar field 100 and/or distributed across a surrounding area 300 of the solar field.

The clouds managing system comprises a cloud management module for collecting cloud data of the sensor units 101 associated to the cloud position 201 of the cloud 200 and/or associated to the current cloud movement 202 of the cloud 200. The cloud management module is designed such, that based on the cloud data a probable cloud movement of the cloud 200 can be predicted.

The cloud management system comprises many cloud sensor units 101, which are spread all over the solar field 100 and the surrounding area 300 of the solar field.

The sensor units 101 are constantly, on line, feeding data to the cloud management module that calculates and analyzes the clouds coverage area at every given moment. After analyzing the data, the cloud management module can predict the cloud movement and its expected coverage area and location in time.

In one embodiment every solar collector comprises a sensor unit (sun sensor unit) . In an alternative embodiment, not every solar collector comprises a sensor unit. For instance, just every second solar collector is equipped with a sensor unit. Every single sensor unit is a node, indicating the existence or non-existence of a cloud above it. All nodes together are creating a mesh that is mapping the clouds above the solar field.

The clouds managing system is constantly collecting the cloud data. By analyzing the cloud data the clouds managing system can learn about the cloud movement direction and speed. Thus in the course of time the clouds managing system will be able to forecast the movement of clouds.

When a cloud is expected to move a solar collector will be illuminated by solar radiation. The solar collector will be commanded to start tracking the sun in advance and the flow rate of the heat transfer fluid) will be adjusted accordingly.

On the contrary, when a solar collector is being shaded, sun tracking will be suspended and the flow rate will be reduced. This is advantageous in order to prevent a flowing of hot heat transfer fluid through a "cold" solar collector.

Based on the conclusions of the clouds managing system, the solar field control systems can take on-line decision. For instance it- instructs for changing the flow rate for individuals loops of the solar field, e.g. quarter of the loops or ail the loops of the entire solar field.

Depending on the clouds coverage area and the duration of time of the coverage, the control system might dictate the reduction in turbine load (for reduction in consumption of the thermal energy of the heat transfer fluid) . By this it is possible to extend an operation time of the energy generation. Unnecessary shutdowns can be avoided. But in some cases a total shut down might be dictated as well . The clouds managing system performance can be divided into three steps :

Continually, and on line data collection of solar fields measurements for clouds mapping over the solar field area.

Analyzing data for smart prediction of clouds position, coverage and movement over the Solar field area, combing with the performance prediction model .

Sending the optimized operation mode for the solar power station control system of the solar field.

The method for operating the clouds managing system is carried out by following steps:

a} Detecting the current cloud position and/or detecting the current cloud movement of a cloud by the sensor units and collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, by the cloud management module; and

b} Predicting a probable cloud movement of the cloud by the cloud management module based on the cloud data.

Example: The solar field is divided into four quarters Ql {111}, Q2 (112), Q3 (113) and Q4 (114) {figure. Following shadowing of the quarters (clouds coverage area) of the solar field are detected by the sensor units:

Based on the detected clouds coverage area following data resu by the cloud management tool:

Following reaction scheme can be set up, based on different leve (solar field level, quarter level or loop level) :

Claims

Patent claims

1. Clouds managing system for a solar field (100) with a plurality of solar collectors {102} , the clouds managing system comprises: - A plurality of sensor units (101} for detecting a current cloud position (201) of a cloud (200} and/or a current cloud movement (202) of the cloud (200) , wherein the sensor units (101) are distributed across the solar field (100) and/or distributed across a surrounding; area (300) of the solar field (100) ; and - a cloud management module for collecting cloud data of the sensor units (101) associated to the current cloud position (201} of the cloud (200) and/or associated to the current cloud movement (202} of the cloud {200} , wherein the cloud management module is designed such, that based on the cloud data a probable cloud movement of the cloud can be predicted.

2. Clouds managing system according to claim 1, wherein the cloud management module is designed such, that a mode of operation of at least one of the plurality of the solar collectors can be adjusted as a function of the cloud data.

3. Clouds managing system according to claiml or 2, wherein at least one of the plurality of sensor units is usable for sun tracking .

4. Clouds managing system according; to one of the claims 1 to 3, wherein at least one of the plurality of sensor units comprises a cloud imaging device.

5. Solar field with a clouds managing system according to one of the previous claims .

6. Method for operating the clouds managing system for a solar field according to one of the claims 1 to 4, the method comprising: a) Detecting the current cloud position and/or detecting the current cloud movement of a cloud by the sensor units and collecting cloud data of the sensor units associated to the current cloud position of the cloud and/or associated to the current cloud movement of the cloud, by the cloud management module; and

b) Predicting a probable cloud movement of the cloud by the cloud management module based on the cloud data .

7. Method according to claim 6 with following additional step: Adjusting a mode of operation of at least one of the solar collectors as a function of the cloud data.

8. Method according to claim 5 or 6, wherein the sensor units are constantIy online .