SOLAR POWER IN CARS

Solar energy is one of the many renewable sources of energy that is used for fueling vehicles, running consumer products and for the efficient running of homes and business establishments. Solar power is harnessed with the help of solar cells and solar panels which are placed in the item that has to be powered.

The solar car is something that is envisioned to materialize in the future, with some countries already having solar cars racing across countries.
With this, it is proven that it is viable to indeed produce and manufacture solar power cars in bulk, in the near future so that everyone will soon own a solar power car.

Of course, once solar power cars are manufactured, it does not implicate that all other fuel sources for cars on highways will be removed. All that is done in solar power cars is the supplementation of traditional fuel with solar energy so that you save not only on your economy, but also save the environment in more ways than one every year.

The solar power cars that are used in races today run only on solar power, and thus look odd in appearance. This is because these cars are designed in such a way that they can collect maximum solar energy with which it is possible for the car to gain the required speed and desired efficiency.

The solar cells used in solar power cars are large, and usually cover the entire vehicle. However in case of commercial uses, solar cells are much smaller and designed so that the vehicle not only looks attractive, but is also efficient in its functioning. Solar cars can be used for short commutes in town as these cars can work only on solar energy.

The batteries found in the vehicle stores excess solar power so that this power can be used when solar power is not available on demand like on cloudy days and at nighttime. The engines found in these solar power cars are very much like the engines found in electric cars found today. In addition to this, the cars are lightweight, so that solar power can be used more efficiently.

At present, there are many types of solar power cars in the development stage today, which are also available for sale. However as these cars are in the developmental stage, the car is not available to the general public. With so many benefits found in solar power cars, its cost will not be much higher than the cost of the traditionally powered vehicles of today.

Another benefit of solar power cars is there is no hassle of stopping at gas stations for gas nor is there the need of getting worried of rising gasoline costs. With a solar power car, you save on the money that you would have otherwise have needed for buying fuel to run your car. In addition to this, with solar power cars you will be doing your bit in stopping global warming problems as there are no fuel emissions from solar power cars.

Design of Screw Conveyor

The size of screw conveyor depends on two factors

1. The capacity of the conveyor

2. The lump size of the material to be conveyed (Maximum dimensions of the particle)

Usually there are three ranges of lump sizes which are considered for selection of screw size. These are:

· A mixture of lumps and fines in which not more than 10% are lumps ranging from maximum size to one half of the maximum, and 90% are lumps smaller than one half of the maximum size.

· A mixture of lump and fines in which not more than 25% are lumps ranging from the maximum size to one half of the maximum, and 75% are lumps smaller than one half of the maximum size.

· A mixture of lump only in which 95% or more are lumps ranging from maximum size to one half of the maximum size and 5% or less are lumps less than one tenth of the maximum size.

The allowable size of a lump in a screw conveyor is a function of the radial clearance between the outside diameter of the central pipe and the radius of the inside of the screw trough, as well as the proportion of the lumps in the mixture.

The lump size of the material affects the selection of screw diameter which should be at least 12 times larger than the lump size of a sized material and four times larger than the largest lumps of an un-sized material.

Example, if screw diameter is 250mm means radial clearance is 105mm, & Maximum lump size is 60mm of 10% lumps.

Capacity of Screw Conveyor:

 

The capacity of a screw conveyor depends on the screw diameter, screw pitch, speed of the screw and the loading efficiency of the cross sectional area of the screw. The capacity of a screw conveyor with a continuous screw:

Q = V. ρ

Q = 60. (π/4).D².S.n.ψ.ρ.C

Where,

Q = capacity of a screw conveyor

V = Volumetric capacity in m³/Hr

ρ = Bulk density of the material, kg/m³

D = Nominal diameter of Screw in m

S = Screw pitch in m

N = RPM of screw

Ψ = Loading efficiency of the screw

C = Factor to take into account the inclination of the conveyor

 

Screw Pitch:

Commonly the screw pitch is taken equal to the diameter of the screw D. However it may range 0.75 – 1.0 times the diameter of the screw.

 

 

 

 

Screw Diameter:

 

Nominal Size D	Trough height from center of screw shaft to upper edge of the trough	Trough width C	Thickness of Tough	Tubular shaft (d1 * Thickness)	Outside diameter of solid shaft	Coupling diameter of shaft
Heavy Duty	Medium Duty	Light Duty
100	63	120	–	2	1.6	33.7*2.5	30	25
125	75	145	–	2	1.6	33.7*2.5	30	25
160	90	180	5	3.15	1.6	42.4*2.5	35	40
200	112	220	5	3.15	2	48.3*3.5	40	40
250	140	270	5	3.15	2	60.3*4	50	50
315	180	335	5	3.15	–	76.1*5	60	50
400	224	420	5	3.15	–	76.1*5	60	75
500	280	530	5	3.15	–	88.9*5	70	75

RPM of Screw:

The usual range of RPM of screw is 10 to 165. It depends on the diameter of screw and the type of material (Max RPM of screw conveyor is 165)

Loading efficiency:

The value of loading efficiency should be taken large for materials which are free flowing and non abrasive, while for materials which are not free flowing and or abrasive in nature, the value should be taken low:

Ψ = 0.12 to 0.15 for abrasive material

= 0.25 to 0.3 for mildly abrasive material

= 0.4 to 0.45 for non abrasive free flowing materials

Inclination Factor:

The inclination factor C is determined by the angle of screw conveyor with the horizontal.

 

Angle of screw with the horizontal	0°	5°	10°	15°	20°
Value of factor C	1	0.9	0.8	0.7	0.65

Types of screw flight:

The screw of the conveyor may be right hand or left hand, the right hand type being the usual design. The threads of the screw may be single, double or triple.

The flight of the screws may be made in either of the two ways:

1. As Helicoids

2. As Sectional flight

Helicoids Flight:

They are formed from a flat bar or strip into a continues helix. The threads are thinner at the outer edge and thicker at the inner edge.

Sectional flights:

Sectional flights are formed from a flat disc and the thickness of the thread is uniform throughout. A continuous helix is made by joining a number of sectional flights together on a piece of pipe and butt welded them. Various styles of screw flights are in use, depending on the service required.

Some of the typical configurations are:

1. Short pitch or continuous flight:

If the conveyor is required to handle dry granular or powdered materials that do not pack, this style of flight may be selected. It is of regular construction and recommended for inclined conveyors having a slope of 20 or more, including vertical conveyors. This style is extensively used as feeder screw.

2. Ribbon flight:

If the conveyor is to handle lumpy, clinging, sticky, gummy or viscous substances, this type flight may be selected. It consists of continuous helical flight formed from steel bar and secured to the pipe by supporting lugs.

3. Cut flight:

In this type of flight screws have notches cut in the periphery of the flight. These notches supplement the conveying with moderate mixing action. They are recommended for conveyors required to handle light, fine, granular or flaky materials.

4. Cut and folded flights:

This type of flight is characterized by notches as in cut flight, together with folded segments. This type of flight creates agitation and aeration resulting in better mixing. This type of flight is used to handle light or medium weight materials having fine, granular or flaky materials.

5. Some screw conveyors have cut flight with paddles mounted at regular intervals. The paddles counteract the flow of material past the flight resulting in greater agitation and mixing.

6. Sometimes screws are made of stainless steel to suit special requirements, like the sanitation requirements for handling food, drugs and other hygienic materials.