Solar energy

Solar energy in buildings

Victor Lapuerta Sanchez
Group: 7I - Autumn Semester 2012

Index

Thermal energy 3
Components 3
Collector 3
Fluid 4
Storage heater 5
Heat exchanger 5
Pumps 5
Expansion vessel 7
Types of solar collectors 8
Flat plate collectors 8
Evacuated tube collectors 8
Concentrating collectors 9
Classification according to the temperature 9
Joint ofsolar panels 10
Calculations 11
Calculation of the collecting surface. 11
Calculation of the performance of a collector 11
Calculation of the amount of energy received in a panel 11
Calculation for optimizing the orientation and inclination of the panels 12
Determination of the losses suffered by the shadows 12
Different systems and how they work 12
Centralized solar and auxiliarysystem 13
Centralized solar system and individual boiler (I) 14
Centralized solar system and individual boiler (II) 15
Centralized solar system and individual boiler (III) 16
Passive 17
Watching the entry of sunlight into our house 17
The orientation of the building 18
Morphology of the building 18
Materials 18
Specific architectural elements to take in solar energy 19
Greenhouseattached to the facade heading to the Ecuador. 19
Wall heater shaped honeycomb 19
Trombe wall 20

Thermal energy

Thermal energy consists in using energy to obtain heat. All the objects exposed into the sun absorb a part of the sunlight that fall upon them. It causes that the material warms up and acquires certain heat. By doing this, we can warm up water through the energy from the sunusing a solar water heating system. This system is formed by different components.
Components
Collector
The solar thermal converter converts solar energy into thermal energy by a fluid. The conversion is performed by a metal plate which transfers the heat energy to a liquid in contact with the plate. Other elements of the collector are:
Transparent cover allows to get more energy by knowngreenhouse effect. It prevents the infrared radiation emitted by the absorber is lost, allowing to this energy back to the absorber plate and to be exploited. The cover provides the necessary sealing to prevent entrance of water or air. Paying special attention to its mechanical strength, since it must withstand the force of wind or snow pressure. The glass is the material more used.
The energetictransmission should be high and depends on the thickness, the angle of incidence and type of glass. They are usually annealed or tempered, improving mechanical properties without degrading the optical. It has to bear possible external pressures and fast dilations or quenching (due to storms). Plastic - They have similar optical properties than glass, facilitating also the greenhouse effect. They arelightweight and rigid, they also have low thermal conductivity. The disadvantages are the potential to expand and bulge because plastic is unstable to UV light, reducing energy transmission over time. Double glazing – It increases the greenhouse effect and reduces losses by convection. It raises the temperature of the absorber plate and the heat transfer fluid. However, they are high in price andoptical losses so this kind of glazing will be applicable only in cold conditions.
The absorber receives and converts solar radiation into heat which is transmitted to the heat transfer fluid. The shapes are diverse: metal plates separated a few millimeters, a metal plate with welded or inlayed pipes or two metal plates with a circuit inside. The face exposed to the sun should capture the mostpossible sunlight so it is usually painted black or dark colour to achieve a selective surface (highly absorbent and low emissivity). It is important to avoid thermal bridges between the absorber and the frame, it should be well insulated.
The subsequent isolation should have low thermal conductivity because it is used to reduce thermal losses in the rear of the absorber. The materials can be...