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Chapter 1

1. Which forms of energy are known to you? Give examples!

Kinetic energy: Thermal Energy, Mechanical Energy, Magnetic Energy. Potential Energy: Chemical Energy, Elastic Energy, Nuclear Energy, Gravitational Energy. Acoustic energy, Radiation energy.

2. What heat energy is needed to heat 1 liter of water from 10°C to 98°C? (Heat capacity of water CWater = 4.19 kJ / (kg K)) Which stage of energy conversion is this?

𝑄 = 𝑐 ∗ 𝑚 ∗△ 𝑇 = 4.19 * 1 * (98-10) = 369KJ This is Final Energy.

5. Comment on the evolution of the world energy demand with the help of the graphic below!

①: After the worldwide economic crisis (1929): Abrupt rise of the energy budget.
②: Increasing importance of natural gas.
③: Crude oil price crisis
④: Exponentially rise of the crude oil-delivery rate
⑤: Increasing importance of nuclear power. However, till today the share of nuclear power to the primary power demand is quite low. Coal; crude oil and natural gas cover 85% of the worldwide primary power demand.

9. What does a temperature increase on the earth’s surface by a total of 2℃ or by 0.1℃ per decade for humanity mean? Name and discuss the respective scenarios!

A 2℃ or 0.1℃ per decade temperature increase can lead to severe impacts like extreme weather, rising seas, ecosystem disruptions, and human health risks.

12. Describe the basic structure of a Dish Stirling system! Label the following sketch!

①: Parabolic dish
②: Elevation support
③: Circular support
④: Drive unit rack
⑤: Electronic control box
⑥: Azimuthal drive unit
⑦: Basement
⑧: Azimuthal drive unit rack
⑨: Turning device
⑩: Stirling engine supporting framework
⑪: Stirling engine

Chapter 2

1. What is Nuclear Fusion? Explain the basic principle of Nuclear Fusion

Nuclear fusion is the process of atomic nuclei combining to form a new nucleus. This reaction powers the sun and stars, releasing energy. Fusion reactions can be either exothermic (releasing energy) or endothermic (absorbing energy).

2. What is Nuclear Fission? Explain the basic principles of Nuclear Fission.

Nuclear fission is the process in which an atomic nucleus splits into two or more smaller nuclei, releasing a significant amount of energy. It can lead to a chain reaction, unlike fusion.

3. What are Solar Winds? What is the effect of Solar Winds on the earth?

Solar winds are streams of charged particles expelled from the Sun that can cause magnetic field disturbances, ionospheric effects, particle hazards, and contribute to atmospheric escape.

4. Why are lower irradiance levels usually measured on Earth than in space?

Lower irradiance levels are typically measured on Earth than in space due to atmospheric reflection, absorption, Rayleigh scattering, and Mie scattering caused by components of the atmosphere and particles in the air.

9. In the following solar orbit diagram, the shading effects are entered in the form of an object traverse. Rate and discuss the shading effects!

These calculations are performed for all obstacles in the vicinity of the solar system. Object height and distance to the observer point must be known Silhouette of the environment in the form of a polygon (= object polygon) is entered in a sun orbit diagram Read when shadowing occurs

11. Which environmental boundary conditions lead to significant shading losses, which must be taken into account when constructing solar systems? Which rule of thumb is followed to avoid shading losses?

Minimize shading losses in solar systems by considering these factors:

1. Buildings: Keep a distance of at least 2.7 times the height of the shadow-casting edge from the solar facade.
2. Trees/Vegetation: Maintain a distance of at least 2 times the height for stand-alone conifers. Be cautious with deciduous trees due to extended foliage periods.
3. Topography: Shading effects are influenced by nearby objects’ altitude. Northern slopes increase shading, while southern slopes decrease it. Follow these guidelines to reduce shading and optimize solar system efficiency.

Chapter 3

2. When solar drinking water heating two fundamentally different systems are used. Describe these systems by naming advantages and disadvantages! Use sketches!（只要左边那个）

3. In a 300l drinking water heat exchanger, the water is heated to 50oC via a solar system. Calculate the stored heat at an ambient temperature of 20oC ! (CWasser = 4,181 kJ/(kg K)=1,161 Wh/(kg K) ; Wasser = 0,9881 kg/Liter)

4. The average hot water requirement of a multi-person household is 50 liters per day and person. Determine the specific useful heat in Wh / (day and person) for a hot water temperature of 45oC and a chilled water temperature of 15oC! (CWasser = 4,181 kJ/(kg K)=1,161 Wh/(kg K) ; Wasser = 0,9881 kg/Liter)

Chapter 4

1. What types of concentrators are used in concentrating solar thermal energy? Name and/or sketch types of these systems!

Fresnel Collector; Parabolic trough collector; Point Concentrator(STPP); Dish Stirling

3. Describe the Carnot-Prozess!

Ideal cycle process proposed by Carnot: heat and work are periodically added and removed again. Mechanical Utility: Thermal efficiency: Efficiency of 100% can be achieved only with the heat sink of 0 K, which is why real cycle processes are always below the Carnot efficiency

5. Parabolic trough power plants (PTPP) are also designed in conjunction with thermal storage. Explain their purpose and sketch the course of the power production of a PTPP from 0 o’clock to 24 o’clock with a sunshine time of 6 to 19 o’clock! Which storage media are used here! Give an explanation!

Excessive gasification by natural gas should be avoided. Integration of a thermal storage is better! 2-tank systems.

• Loading: Liquid salt is pumped from the cold to the hot tank (T ≈380𝑜𝐶)
  
• Discharging: Liquid salt from the hot pumped back into the cold tank
  
• Temperature of the cold tank (T ≈280𝑜𝐶)> solidification temperature of the salt
  

Chapter 5

1. Explain the photo effect!

1839: Becquerel discovers the photo effect. The energy of the photons (with wavelength) of the light is calculated by: E=hc/ c = Speed of light: 3108 m/s h = Planck’s effect quantum = 6,626075510-34 Js The release of electrons from the nucleus from the atomic composite by photons is called an external photoeffect. For example, if a photon with the energy of 13.59 eV (1 eV = 1,6021810-19 J) hits the electron of the first web in hydrogen, this energy is sufficient to release the electron completely from the nucleus.

2. What is meant by doping a high-purity silicon cell?

On the one hand, the silicon is doped with phosphorus atoms in a ratio of 1 phosphorus atom to 1 million silicon atoms. The other side of the silicon slices is doped with the element boron (three-valued). Boron has an electron less than is needed to fit into the crystal; “Holes” are created, which are also called “defect electrons”.

Chapter 6

2. Give the approximate cW value of the bodies shown below!

①1.1到1.3 ②0.6到1.0 ③0.3到0.4 ④0.4(closed), 0.34(closed back)
⑤0.16到0.2 ⑥0.07到0.09 ⑦0.055 ⑧1.2(closed), 1.3(open front)

3. Describe possibilities for power limitation and windstorm of wind turbines!

Stall control: Stall-controlled systems maintain constant rotor speed but are prone to turbulent stalls, limiting predictability and maximum power output.
Pitch control: The rotor blade actively adjusts its angle of attack to optimize power production and prevent stall, requiring additional energy.

4.Please complete the following sketch!

①: wind measurement
②: rotor blade
③: gearbox
④: hub
⑤: generator
⑥: azimuth drive
⑦: nacelle
⑧: tower