Solar Thermoelectric Ventilator

Researchers

Badea Radu

Zulean Tiberiu

Table of Contents

Abstract IntroductionMaterials and Methods ResultsDiscussionConclusion Acknowledgments References/Bibliography

AbstractThis research is about a ventilator which is not using electric current of city. This ventilator can run on a summer day for free by using thermoelectric effect and solar energy as an energy source. The solar thermoelectric ventilator is a thermoelectric generator which demonstrates the direct conversion of heat into electrical energy using the Seebeck effect. Unusually there is no mechanical movement involved. The key component is the Peltier element that is connected to two aluminium U-profiles using a clip. One aluminium profile conducts heat from a reservoir with hot water to one side of the Peltier element. The other profile conducts heat from the back side of the Peltier element to a cold water reservoir. As long as there is a temperature differential of about 10 degrees between the two sides of the Peltier element, sufficient electricity is generated to power the electric motor and turn the propeller. Hot water reservoir and cold water reservoir are placed out of house. Propeller is in the house. Sun heats the water in hot water reservoir. Cold water reservoir is filled with water. Propeller turns because of generated electricity.

IntroductionSome countries like in Africa and South Asia have sunny weather generally. People can use solar energy to generate electricity and to refresh on hot days. People can have ventilator without paying for electricity.On a hot summer day, people want to refresh themselves. The sun is the source of hotness. However the sun can be source of energy. The sun heats the water. Hot water activates electrons on metals and electricity is generated by the help of a peltier element. This energy is not big but it is enough to run a ventilator.

Materials and MethodsThe thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice-versa. A thermoelectric device creates a voltage when there is a different temperature on each side. This effect can be used to generate electricity, measure temperature or change the temperature of objects. Because the direction of heating and cooling is determined by the polarity of the applied voltage, thermoelectric devices are efficient temperature controllers.The Key Component; The Peltier Element The Peltier effect is the presence of heat at an electrified junction of two different metals When a current is made to flow through a junction composed of materials A and B, heat is generated at the upper junction at T2, and absorbed at the lower junction at T1.

(Figure of thermoelectric generator)

We used 1,5 L hot water at 45oC and 1,5 L cool water at 15oC. There are two aluminum plates and two peltier elements. Specifications of peltier element are I max.: 6.0 A Delta T max: 67 C Voltage: 15.4 V Q max: 51.4 W Number of pairs: 127 conveyors: CP1.4-127-06L Dimensions: 40 x 40 x 3.8 mm Weight: 21.8 g

ResultsWe used 1,5 L hot water at 45oC and 1,5 L cool water at 15oC. There are two thin aluminum plates and two peltier elements. 0.325 V is produced and ventilator turned.Vernier data logger is used to get data.1st ExperimentPotential Time graphic

0 -0.325091575092Data got inside without Sunlight and cool water reservoir has no isolation. Hot water cooled and cool water warmed. We started with 30oC difference and after 180 sec. Temperature difference decreased to 26.6.

10-0.32509157509220-0.32509157509230-0.33119658119740-0.32203907203950-0.32814407814460-0.31593406593470-0.31898656898780-0.32203907203990-0.318986568987100-0.300671550672110-0.300671550672120-0.291514041514130-0.297619047619140-0.282356532357150-0.282356532357160-0.279304029304170-0.276251526252180-0.276251526252

2nd Experiment

Comparison

1st experiment2nd experiment

Distance between water level and two peltier elements8 cm6 cm

The produced voltage0.3250.343

Insulator noyes

Temperature change in the same water reservoir3.80.8

Average temperatures of Some CitiesIf average temperature is around 30oC, temperature of water in a closed container can reach around 50oC.

Cairo's ClimateMonthPrecipitation MaximumMinimumAverage Sunlight

incmFCFCHours

January0.20.564184687

February0.20.569214898

March0.20.5752451119

April0.10.38228571410

May0.10.39133621710

June009535682012

July009736702112

August009535712211

September008932682010

October00863064189

November0.10.3792657148

December0.20.5682050106

Aswan's ClimateMonthPrecipitationMaximumMinimumAverage Sunlight

incmFCFCHours

January00732350107

February00792652117

March00883157148

April00973666199

May001023973239

June0010742792610

July0010541792610

August0010541792610

September001023975249

October00983771228

November00883162178

December00772553127

july and august: 33oCDhaka, Bangladesh

DiscussionWe observed that produced voltage depends on some variables. Temperature difference Types of metal Distance between water level and peltier elements Thickness of metal

Temperature differenceKeeping temperature difference between water reservoirs is the main problem. Temperature of hot water must be kept around 50 oC or more. Average temperature of the cities is more than 30 oC. If the reservoir is is closed and covered (or painted) black, temperature can increase around 50 oC. On the other hand keeping water cool is harder on a hot day. We thought that cool water reservoir was placed in the house but it was not practical. Aluminum plate must pass through the wall of house. Then we thought that cool water container must be covered by an insulator. We used polystyrene and aluminum foil.

Types of metalWe used aluminum plates. Thermal conductivity of aluminum: 237Wm1K1 . Its conductivity is good enough. Thermal conductivity of copper: 401Wm1K1 , Thermal conductivity of iron: 80Wm1K1 We used aluminum because it is cheaper and it can be bent easier. Distance between water level and peltier elementsWe placed peltier elements 6 cm above. When we placed 8 cm above, we got 0.02 V less. Therefore peltier elements must be placed as closer as it can. Thickness of metalThickness of metal affects the produced voltage. We used 1 mm thicker aluminum plate in the 2nd experiment.DurabilityWhatever we do, cool water is heated. Then voltage decreases because of not enough temperature difference. When the ventilator stops we must replace water in cool water reservoir because it is not cool enough. However we can increase duration of working ventilator. If 5 L reservoirs are used instead of 1,5 L reservoirs, propeller can turn more. Amount of water in reservoirs does not change the voltage, but increases durability of produced voltage.

ConclusionThe Solar Thermoelectric Ventilator works without an external electricity source. The sun is the energy source. The sun heats water. Peltier elements generate electricity and ventilator works. After getting materials, people will not pay for anything except replacing water. Actually people can use replaced warm water.The Solar Thermoelectric Ventilator can be used in hot and poor countries where they have electricity shortage and electricity cuts off.The Solar Thermoelectric Ventilator is environmentally friendly. Batteries can be used for ventilators. However they contain metals and damage to the environment. Batteries must be disposal in specific methods.

LimitationsThe Solar Thermoelectric Ventilator is proper for hot and poor countries.The Solar Thermoelectric Ventilator can work after 11 o`clock to the evening because it needs the sun to work.Water in cold water reservoir must be replaced if ventilator stops. Ventilator can stop if temperature difference is not enough. Water in cold water reservoir is going to be warm because of weather and heat transfer.

AcknowledgmentsWe thank to parents and physics teacher. physics teacher helped us about data logger

References/Bibliographyhttp://www.thermoelectric-generator.com/brief_explaination_of_thermoelectric_power_generation.htmhttp://en.wikipedia.org/wiki/Thermoelectrichttp://en.wikipedia.org/wiki/Aluminiumhttp://goafrica.about.com/library/bl.egypt.weather.htmhttp://www.weather.com/outlook/travel/vacationplanner/vacationclimatology/monthly/AFXX0003