Integrated CPV advanced tracking system.
In high concentration CPV systems (Concentration Photovoltaics) it is mandatory that concentrators are aligned to the sun within certain optical acceptance angle characteristic to those modules. This means that the optical system has some tolerance to tracking deviation.
Concentrators are basically composed of a PV cell on which solar radiation is concentrated by an optical system.
Those concentrators are normally integrated into modules, each module containing a group of concentrators arranged in an array pattern.
CPV systems are composed of multiple CPV modules mounted on top of a solar tracking structure.
It is obvious that in order for the system to work properly it is necessary that all the modules, and therefore all the concentrators within each module, are kept within the design acceptance angle.
A common practice has been to isolate CPV module design from solar tracker design, so that each of these critical components are manufactured independently and system integration is done at the latest stage of the value chain, on the field.
In this de-integrated approach, system installation basically consists in first erecting the solar tracker structure on the field and then mounting individual CPV modules on top of that tracking structure.
It is obvious that field conditions can be very variable and so the skills of personnel involved in field system integration. This has multiple disadvantages which can increase the installation cost and reduce the quality and reliability of the integrated system.
The main problems arising from this de-integrated approach are:
- Need for on field alignment of structural elements in order to assure tracking structure coplanarity or for individual alignment of mounted modules in order to assure module coplanarity on top of a no co-planar structure.
- Tracking structure deformation and unexpected deflections due to assembly or component quality (due to local resourcing) variability on the field.
- Field integration of multiple tracking components, like sensors, motors, drives and control system, introduce multiple potential failure points and increase the requirement of skilled manpower on the field.
- Slow commissioning process as each CPV system must be integrated and tested on the field.
- High maintenance costs due to incidences derived from field integration.
- Many CPV trackers use a fine tuning solar sensor, which is field mounted to the tracking structure, and the field alignment and calibration of this device is a common source of installation and maintenance incidences.
- The fact that modules are field mounted on to of the tracking structures implies a certain degree of structural redundancy between.
Besides these disadvantages, this de-integrated deployment approach has driven the CPV industry to believe that CPV systems would be the larger the better, as under this approach there are obvious economies of scale if the number of trackers per MW is minimized, both on the installation and operation phases.
Summary of the Invention
Our invention objective is to obtain an integrated CPV system (ICPVS) which can be manufactured and tested as a single unit and rapidly deployed on the field without requiring skilled personnel.
Also, we have designed a system with optimized logistics and which can be very efficiently transported from the assembly line to the destination installation site.
Yet another basic objective is to use components requiring zero maintenance for 25 years.
Another objective is to use a very fast to deploy foundation and interconnection system having a low environmental impact, and which would be eventually easy to dismantle.
Main characteristics of the invention are:
- A horizontal tube passing through and supporting two CPV super-modules, using maintenance free polymer bearings.
- A rectangular box holding the previous tube and mounted on a bottom assembly.
- A bottom assembly composed of a higher rotating part and a fixed lower part, which is bolted to a ground post, being also its bearings polymer made and maintenance-free.
- Using square posts driven into the ground as system foundation, by mechanized means.
- Having connection masts bolted to the bottom assembly which allow for aerial electrical and signal interconnection.
Using our ICVPS system, we estimate that it is possible to install 1 MW of solar power per day using a field team of just 10 people.