Principles Ulm
In a building, several energy flows can be observed see Fig. 3.1 . Energy is primarily supplied by means of space heating systems, secondly, heat is created by people, lighting and household appliances so-called internal heat gain , and thirdly, there are passive solar heat gains, such as heat created by transparent surfaces so-called passive solar energy utilisation . Heat losses or heat gains depending on the ambient temperature are due to the heat conductivity of the building envelope i.e....
Info Xno
Fig. 3.12 Thermally decoupled solar system attached to the building envelope see 3-8 Fig. 3.12 Thermally decoupled solar system attached to the building envelope see 3-8 Decoupled systems are characterised by good controllability. Thanks to the thermal insulation between absorber and the internal space, at night heat losses are very low. However, these systems present the disadvantages of high construction costs, a propensity towards defects e.g. leakages and high absorber temperatures....
DishStirling systems
Dish Stirling systems mainly consist of the parabolically shaped concentrator dish , a solar receiver and a Stirling motor as thermal engine with interconnected generator. The parabolic concentrator is tracking the sun in two axes, so that it reflects the direct solar radiation onto a receiver positioned in the focus of the concentrator. The radiation energy transformed into heat within the receiver is transferred to the Stirling motor, which, being a thermal engine, converts the thermal energy...
System components Hno
Parabolic concentrator dish . The parabolically shaped concave mirror dish concentrates sunlight onto a focal spot. The size of this spot depends on concentrator precision, surface condition and focal distance. Common concentrators achieve concentration ratios between 1,500 and 4,000. Common maximum diameters amount to 25 m. With regard to concentrator design facetted paraboloids i.e. consisting of individual segments and full-surface paraboloids are distinguished. - For facetted concentrators...
System elements
Currently and in the near future, almost exclusively grid-connected horizontal three-blade rotors and, to a very limited extent, also two-blade rotors hold a predominant market position. The principle plant design is illustrated in Fig. 7.11. A grid-connected wind power station thus consists of rotor blades, rotor hub, gearbox, if applicable, generator, tower, foundation and grid connection. Depending on the respective wind energy converter type further components may be added. Fig. 7.11 also...
Mw
a sufficient for a 80 MW power plant without storage. a sufficient for a 80 MW power plant without storage. Investments. Investment costs for such a power plant vary between 220 and 300 Mio. . Here a mean of approximately 260 Mio. is assumed. Specific investment costs therefore amount to 5,200 kW, including storage. Table 5.8 shows the approximate distribution of the investment costs. Table 5.8 Estimation of the investment costs of a parabolic trough solar power plant Table 5.8 Estimation of...
Info Qpl
Temperature of the produced thermal waters n C Temperature of the produced thermal waters n C Fig. 10.15 Specific average resource utilisation of different cycles suitable for geothermal power production ORC - Organic Rankine Cycle Kalina - Kalina Cycle Open systems. Depending on the characteristics of the geothermal resource either direct steam utilisation systems or flash systems are possible. Flash systems are further divided into single flash systems without condensation, single flash...
Energy conversion chain losses and characteristic power curve 1
Energy conversion chain. Wind energy utilisation converts energy extracted from moving air masses into electrical energy. Conversion usually involves several steps as illustrated in Fig. 7.14. As shown in the illustration, kinetic energy of moving air masses is first converted into rotation of the rotor and thus into mechanical energy of the power train. Power trains of conventional wind energy converters include an inserted mechanical gearbox to increase the number of revolutions for the...
Info Bfh
The fact that for example the annual cycle of the solar radiation can vary significantly is also shown in Fig. 2.14. This graphic displays the global radiation at Stockholm Sweden, Kuala Lumpur Malaysia, Victoria Argentina, Bechar Algeria and Manaus Brazil. The relatively far north located city of Stockholm shows a well developed annual cycle. The same characteristic also shows the city of Victoria but mirror-inverted. This is due the fact that Victoria is located in the southern hemisphere and...
System components Nnz
As follows the main system components of a solar pond power plant are described in detail. Pond collector. Pond collectors are either natural or artificial lakes, ponds or basins that act as a flat-plate collector because of the different salt contents of water layers due to stratification. The upper water layers of relatively low salt content are often provided with plastic covers to inhibit waves. This upper mixing zone of such pond collectors usually is approximately 0.5 m thick. The...
Solar pond power plants
Solar ponds are power plants that utilise the effect of water stratification as a basis for the collector. A basin filled with brine i.e. a water salt mixture functions as collector and heat storage. The water at the bottom of the solar pond serves as primary heat storage from which heat is withdrawn. The deeper water layers and the bottom of the solar pond itself serve as absorber for the impinging direct and diffuse solar radiation. Due to the distribution of the salt concentration within the...
Info Kug
Fig. 5.22 Working principle of a Stirling motor see 5-24 Fig. 5.22 Working principle of a Stirling motor see 5-24 The expanding working gas moves the working piston to the open side and performs work. If the working piston passes the lower dead centre and is thus moved to the closed side, the hot working gas is forced to pass the regenerator and to move into the cold room. Heat is transferred isochorously from the working gas to the regenerator isochorous cooling phase 3 Fig. 5.22 . The gas is...
Ff
Reduction factor of the g-value due to the window frame Axial component of the lifting force Tangential component of the lifting force Reduction factor of the g-value due to fixed shading Fwi, slow Force given by the wind energy converter slowing down the wind flow Fw ,weC Overall wind force affecting the wind energy converter g Energy transmittance factor g-value gdiff n Diffuse energy transmittance factor diffuse g-value Gabs Radiation flux density of the absorber Gap Radiation flux density...
Info Hcr
within the converter resp. within the grid Fig. 7.14 Energy conversion chain of a wind energy converter transfor. Transformator, resp. respectively see 7-1 Losses. The different conversion steps are illustrated in Fig. 7.14. According to this they are subject to several loss mechanisms which may reduce the overall efficiency significantly in comparison to the Betz power coefficient of 59.3 . Commercially available wind energy converters only transform 30 to 45 of the energy contained in...
Utilisation of Ambient Air and Shallow Geothermal Energy
A typical characteristic of ambient air and near-surface heat it is the very low temperature level. The heat is mainly generated by solar radiation Chapter 2 . Only a small part of the energy in the soil i.e. shallow geothermal energy is not produced by the sun, but by the geothermal energy flow caused by the heat potential available within the earth i.e. deep geothermal energy . The share of geothermal energy normally increases proportionally with an increasing depth underneath the surface of...
List of Authors
Institute for Energy and Environment IE gGmbH, Leipzig, Germany Dr. Ernst Huenges GeoForschungsZentrum GFZ , Potsdam, Germany Prof. Dr.-Ing. Klaus Jorde Center for Ecohydraulics Research, University of Idaho, Boise ID , USA Dr. Reinhard Jung GGA-Institute, Hannover, Germany Dr.-Ing. Frank Kabus Geothermie Neubrandenburg GmbH, Neubrandenburg, Germany Prof. Dr.-Ing. Martin Kaltschmitt Institute of Environmental Technology and Energy Economics, Hamburg University of Technology, Germany Institute...
Plant concepts Flf
Fig. 5.34 shows the general structure of a solar pond power generation plant. According to this graphic, the water absorbs the incident direct and diffuse radiation, similar to the absorber of a conventional solar collector, and is heated up. The technically adjusted salt concentration prevents natural convection and the resulting heat loss at the surface due to evaporation, convection and radiation. Fig. 5.34 Plant diagram of a solar pond power plant Fig. 5.34 Plant diagram of a solar pond...
T Ohx
Fig. 5.4 Temperature entropy-diagram 7 gt -diagram of a closed left, a and an open cycle right, b the arrows refer to the direction the cycles performed - If the working medium is part of an inexhaustible reservoir e.g. ambient air and its final state is different from the initial state, the process is referred to as an open cycle Fig. 5.4 yet, strictly speaking, such a process is also closed since the last state change takes place outside of the actual process, namely within the inexhaustible...
Power control
Wind energy converters require appropriate control mechanisms to limit power extraction at higher wind speeds Fig. 7.17 . Power controls prevent mechanical deterioration of the rotor and are also required due to the capacity thermal limitation of the generator i.e. matching the installed electric capacity . On principle, power and speed controls need to be distinguished 7-3 . If the number of revolutions must be kept constant, or almost constant, power has to be controlled accordingly. It must...
Wind parks
Wind park design. Wind energy converters may be installed individually in exposed positions, for instance at the hilltops of low mountain ranges with free airflow, in rows e.g. converters positioned along a dike or in groups e.g. positioned in lines, one behind the other . For the latter two variants certain minimum distances, depending on the respective site conditions, need to be observed, to prevent reciprocal shut-down of the converters and to ensure relatively undisturbed wind conditions...
Info Ejp
80 90 100 110 120 Parameter variation in Fig. 6.33 Parameter variation of the main influencing variables on the specific power production costs of the 20 kW photovoltaic multi-crystalline generator at Site 1 indicated in Tables 6.3 and 6.4 Yet, in particular cases and under different site conditions, power production costs may differ tremendously from the magnitudes indicated in Table 6.4. To estimate the impact of such influences on the power production costs, Fig. 6.33 illustrates a...
Drag and lift principles
There are two different principles available for technically exploiting moving airflow by rotating wind energy converters, which can also be combined under certain conditions. Energy can be extracted from flowing air masses either by the lift or drag method. In the following both principles are explained. Lift principle. According to the lift principle, wind is deviated to generate peripheral force inside the rotor. For high-speed propeller-type converters, in most cases rotor blades are...
Photosynthetically fixed energy
Biomass in the broader sense is all phytomass and zoomass. An estimated total of 1.84 1012 t of dry mass exists on the continents. The major part of phytomass or plant mass is generated by autotrophic organisms that can generate the energy they need to survive by exploiting solar energy through the process of photosynthesis. Heterotrophic organisms, though, of which zoo mass primarily consists of, need to consume organic substances to produce energy. Biomass can be divided into primary and...
Segs
seismic fracture mapping 480 seismic tomography 481 seismicity 481 seismometer 90 selective absorber 124 selective absorption 33, 34 selective coating 124, 197 selective surface 124 self-assembly 163 self-commutated inverter 266 self-consumption 264, 276 self-monitoring system 269 self-propping effect 479 self-regulating system 150 semiconductor 231 semiconductor grade silicon 245 semiconductor industry 292 semiconductor material 237 semi-hermetic compressor 410 semi-metal 231 semi-passive 119...
T Uqh
Fig. A.8 Temperature variations in relation to ocean depth, simplified illustration according to A-2 In principle, this type of thermal energy could be used for power generation by means of open or closed Rankine processes ORC processes . This cycle is based Fig. A.8 Temperature variations in relation to ocean depth, simplified illustration according to A-2 on the temperature difference between the warm surface water of a maximum of 22 to approximately 28 C and the cold deep waters of...
Conduction mechanisms of semiconductors
Intrinsic conductivity. Semiconductors are conductive beyond a certain temperature level as valence electrons are released from their chemical bonds with increasing temperatures and thus reach the conduction band intrinsic conductivity . They become conduction electrons that are able to move freely through the crystal lattice i.e. electron conduction . On the other hand, also the resulting hole inside the valence band can move through the semiconductor material, since a neighbouring electron...
R
Anti-reflecting coating Front side contact n-Diffusion layer -Base material -Alloy contact Rear side contact Sintering FSC Anti-reflecting coating Electric serveying Fig. 6.9 Scheme of the manufacturing steps of a silicon solar cell manufactured according to the silk-screen process printing FSC front side contact RSC rear side contact according to 6-44 But both, mono-crystalline and poly-crystalline silicon allow achievement of considerably higher efficiencies compared with those obtained by...
Kem
Fig. 10.18 Simplified schematic diagram of a geothermal power production facility operating according to the ORC Organic Rankine Cycle Within the temperature range of fluids extracted from geothermal wells, usually hydrocarbons such as n-pentane, isobutane are applied as working fluids. In the past, also fluorocarbons such as C5F12 have been used. Furthermore, the application of mixtures of hydrocarbons is under consideration, as they promise to enhance efficiencies due to their smooth...
A OWC system
Another system to use wave or breaker energy is generally referred to as oscillating water column abbreviated to OWC . From the current at least short-term viewpoint the OWC system is the most promising type of wave energy converters. Already applied in 1910, the system is probably the first wave-powered generator in history of human mankind. At that time air compressed inside the cave of a rocky shore was exploited. Current technologies, by contrast, aim at using the wave motion in...
Info Mgu
and xenon filling 4 16 4 16 4 mm and xenon filling 4 16 4 16 4 mm The g-value energy transmittance factor of a glass pane is additionally reduced by dust on the glass pane FD and possible fixed shading FS and flexible shading FC. Even for frequently cleaned surfaces, due to dust, a reduction of the g-value by 5 has to be assumed 3-6 . The value needs to be further reduced to consider the inclined radiation incidence. This factor is taken into account by the diffuse g-value in Table 3.2 and...
Principles 1
Mechanisms. Wind is generated as equalising currents, essentially as a result of varying temperature levels on the surface of the earth, by which differences in air pressure have been created. The air masses then flow from higher pressure areas to lower pressure areas. The so-called gradient force caused by the pressure gradient between such a high and a low-pressure zone impacts on an air particle. Additionally, the Coriolis force impacts on each particle within a rotating reference system....
A Ocean currents
It is also possible to exploit ocean currents resulting from different temperatures in different areas. Such an utilisation is particularly sensible at straits where high current speeds are available. For instance, the narrowest section of the Florida Current has a width of 80 km. At this point water throughput varies between 20 and 30 Mio. m3 s at an average speed of 0.9 m s. Based on such an ocean current of an average width of 50 km, an average depth of 120 m and a speed of about 2 m s...
Wasserkraftanlage Plannung Bau Und Betrieb Giesecke J. Mosonye E.
1-1 Kaltschmitt, M. Renewable Energies Lessons Institute for Environmental Technology and Energy Economics, Hamburg University of Technology, Summer Term 2006 and Winter Term 2006 07 1-2 Hulpke, H. u. a. Hrsg. R mpp Umwelt Lexikon Georg Thieme, Stuttgart, New York, Germany, USA, 2000, 2. Auflage 1-3 BP Hrsg. BP Statistical Review of World Energy 2005 BP, London, UK, June 2006 www.bp.com 1-4 Kaltschmitt, M. Hartmann, H. Hrsg. Energie aus Biomasse Springer, Berlin, Heidelberg, Germany, 2001 1-5...
Solar updraft tower power plants
For a solar updraft tower power plant the three components of glass roof collector, chimney and turbine are combined. The use of this combination for power generation was already described more than 70 years ago 5-26 . Fig. 5.24 Function principle of a solar updraft tower power plant Fig. 5.24 Function principle of a solar updraft tower power plant The principle, on which a solar updraft tower power plant is based, is shown in Fig. 5.24. The incident direct and diffuse solar radiation warms the...