It is a paraboloid reflecting concentrator with downward facing conical cavity receiver at its focus designed to absorb the concentrated solar energy and to transfer it for useful application. The concentrator tracks the sun on two axes, continuously facing it to capture the maximum amount of solar radiation over a day. The dish concentrator along with the receiver is mounted on a specially designed pillar with the tracking system. The system is equipped with a heat retrieval mechanism (which consist of piping and fittings, insulation, fluid circulating pump, etc.), and system controls related to tracking, thermal system, and security/ emergency measures.
Heat from sun rays can be harnessed to provide heat to a variety of applications such as cooking, cooling, industrial process heating, desalination and generating electricity. But in general, Sun rays are too diffuse to be of direct use in these applications. So solar concentrators are used to collect and concentrate sun’s rays to heat up a working fluid to the required temperature the make Sun’s heat suitable for these applications
The configuration of an industrial process heat solar system depends on the respective application. Broadly, it may consist of one (or more) number of solar parabolic dish, specially designed heat exchangers for transferring solar heat to the existing thermal system in the user industry, fluid pre-treatment equipment and storage vessel (if required), apart from piping/ fittings, fluid circulating pump(s), insulation, control valves etc. on application side for delivery of heat as per the requirements.
Each dish of this technology having a weight of around 150KG could generate around 30Kg of steam in a day depending on the solar insolation and steam pressure. More dishes could be installed for meeting the required steam in an establishment at desired temperature and pressure
Dish Systems comprise of following components
The receiving system (Coil based conical Receiver) collects solar radiation in the solar field from paraboloid reflecting collectors and transfers it to working fluid such as water or oil circulating inside the insulated pipe which passes through the receiver (at Focus point)
The circulation subsystem carries fluid and transfers the heat received by it to the end use application. Fluid circulates in the system at a certain desired flow rate to quickly and efficiently transfer the received heat from the solar field to end use application. Circulation subsystem has a number of components such as pipes, pumps, and valves to control fluid flow and temperature.
The control Mechanism sends signals to these systems to control the tracking of the receiver based on the required temperature of the circulating fluid for a user’s application.
Parabolic Solar Dish Specifications
|Type solar Technology||True Parabolic Solar Concentrator|
|Dish Shape||True Parabola|
|Area of dish||10 m2|
|Area required for installation/dish||22 m2|
|Operation per days||8 hrs./day|
|Total Operation per Year||250-280 days/year|
|Avg. Heat output/dish(Kcal)||UPTO 25,000 Kcal/day|
|Efficiency of our Solar Dish||upto 60%|
|Solar Beam Normal Radiation require||600-700 W/m2|
|Reflectivity of the parabolic dish||Upto 92%|
|Total Weight of Dish with Tracker and Pole||300 KG (approx)|
|Wind speed||Upto 180Km/hr|
|Tracker type||Automatic Dual Axis tracker|
|Seasonal Tracker/Altitude tracking (NS)||Yes|
|Azimuth tracking (EW)||Yes|
|Tracking Mechanism||Real Time (Time Calibrated with reduction gear box)|
|Power consumption:||<=400Watt per month|
|Pillar Height above ground||2200 mm|
|Below ground (If required)||600mm|
Technical specifications of Solar parabolic dish system
|1||Aperture area of the collector||10.5 sq meter|
|2.||Aperture Diameter||3.25 m|
|3.||Focal Length||1.7 meter|
|4.||Surface area||11.7 sq meter approx|
|5.||Shape||True parabolic dish with multiple reflectors|
|6.||Reflector Material||Solar Grade Aluminum Reflector, 0.3 mm thickness, weatherproof coating|
|8.||Protective Coating/Edge sealing||Standard weatherproof coating for low degradation|
|11.||Protection from corrosion||Industrial paint weather resistant coating|
|12.||Mechanism||Automatic Dual Axis tracking (Timer based)|
|13.||Features||Automatic reverse/ forward|
ABOUT COMPOUND PARABOLIC COLLECTOR (CPC)
CPC Design Concepts – An interesting design for a concentrating collector makes use of the fact that when the rim of a parabola is tilted toward the sun, the rays are no longer concentrated to a point, but are all reflected somewhere below the focus. The rays striking the half of the parabola which is now tilted away from the sun are reflected somewhere above the focus. This can be seen in Figure where the rays on the right-hand side are reflecting below the focus and the rays on the left-hand side are reflecting above the focus. If the half parabola tilted away from the sun is discarded, and replaced with a similarly shaped parabola with its rim pointed toward the sun, we have a concentrator that reflects (i.e. traps) all incoming rays to a region below the focal point.
Since the rays are no longer concentrated to a single point, this design is called a non-imaging concentrator. A receiver is now placed in the region below the focus and we have a concentrator that will ´trap´ sun rays coming from any angle between the focal line of the two parabola segments. Receivers can be flat plates at the base of the intersection of the two parabolas, or a cylindrical tube passing through the region below the focus. The basic shape of the compound parabolic concentrator (CPC) is illustrated in Figure below.