Conversion into final or useful energy

Within a supply chain available biomass can be processed and converted into the desired useful energy according to a great variety of methods and options B-1 . The easiest way is to burn lignocelluloses biomass directly within a furnace after mechanical preparation (such as chipping or pressing). However, for numerous other promising applications (such as fuel provision for car or truck engines or highly efficient power generation within a gas turbine) it is recommended or even required to...

Tidal power plants

Tidal energy, i.e. the tidal range, can be exploited according to different methodological approaches. The easiest method consists of a one-basin-system that is only used in one direction (Fig. A.6, top). A bay is separated from the open sea by means of a dam, but remains connected to the sea by a floodgate and a turbine. The control system of the turbine and the floodgate ensures that water can only enter the bay via the floodgate and can only exit the bay through the turbine. This turbine is...

Ara

Connection with the grid from house to house Distribution line Main distribution line Fig. 10.7 Transmission routings (see 10-2 ) Hybrid connection (combination of both options) Hybrid connection (combination of both options) Because of the moisture within the soil, corrosion resistance is the major requirement to be met by the distribution system. Also, moistening of the insulation needs to be prevented with regard to limiting heat losses. Primarily, plastic jacket pipes equipped with steel...

Conventional energy provision systems

The addressed renewable sources of energy and the corresponding technologies can be applied for the provision of heat and or power, by substituting conversion technologies based of fossil fuel energy. It is thus sensible to compare the assessed options of using renewable sources of energy with the corresponding fossil fuel-based options which they are to substitute. For this purpose, standard conventional energy provision technologies based on fossil fuel energy, used for comparison, are...

Definitions

The translucence of walls is often described by the terms opaque, transparent, and translucent, as well as by solar aperture surface. The opaque building envelope is not permeated by light and includes, for instance, brick walls, or a roof covered with tiles. Transparent and translucent parts (e.g. windows) of the building are permeable by solar radiation. In general, the word transparent means clear, whereas translucent parts of the building can not be seen through. In terms of solar...

Economic analysis

Currently grid-connected photovoltaic power generation is mainly performed by means of roof-mounted systems as well with an increasing importance by means of so called photovoltaic power plants. Hence, a typical photovoltaic system of an electric nominal capacity of 3 kW, installed on a slanting roof, will be analysed. Additionally a system located on a horizontal roof of an industrial building with an installed capacity of 20 kW is taken into consideration. To cover the overall market, the...

Economic and environmental analysis

The following sections are aimed at assessing solar tower power plants according to economic and environmental parameters. Economic analysis. Within the scope of the economic analysis, power generation costs will be calculated for the discussed types of solar thermal power plants. In line with the preceding assessment method, applied throughout this book, the costs for construction and operation are determined and distributed in the form of annuities over the technical lifetime of the power...

Energy balance of the earth

The energy flows of the earth are fed from various sources described below. Solar energy has a share of more than 99.9 of all the energy converted on earth. The solar radiation incident on the earth is weakened within the atmosphere and partially converted into other energy forms (e.g. wind, hydro power). Therefore the structure and the main attributes of the earth's atmosphere will also be described in more detail, followed by balancing the global energy flows. Solar energy. The sun is the...

Energy conversion chain losses and characteristic power curve

Grid-connected photovoltaic power generation is aimed at the supply of grid-compatible alternating current (AC), which is provided from radiated solar energy at several energy conversion levels illustrated in Fig. 6.29. As shown in the diagram, solar radiation energy (i.e. diffuse and direct radiation), and thus the photons energy content, is first converted into potential energy of the electrodes of the semi-conductor material they are now able to move freely within...

Energy gap model

Besides the positively charged protons and the uncharged neutrons inside the nucleus an atom is composed of the negatively charged electrons that assume discrete energy levels (such as shells or orbitales) around the nucleus. There is a limited number of electrons that can occupy a certain energy level according to the so-called Pauli exclusion principle any possible energy level may only be occupied by a maximum of two electrons. These two electrons are only allowed if they again differ from...

Environmental analysis

Solar systems are characterised by noise-free operation without direct substance releases. The following analysis of the local environmental aspects differentiates between construction, normal operation and malfunction, plus end of operation. Construction. The environmental effects of the construction of solar systems are generally in line with those of the manufacturing industry. Only the production of the absorber is of particular environmental significance. In the past galvanic coating...

Functional systems

Depending on their form and arrangement, four different functional systems (i.e. direct gain systems, indirect gain systems, decoupled systems, sunspaces) are distinguished however, the borderline between the systems remains fluid. Direct gain systems. Solar radiation penetrates into the living space through transparent external surfaces and is converted into heat at the internal room surfaces. Room temperature and room surface temperature change almost simultane ously. Typical direct gain...

Fx Wa

Grid-connected or off-grid 20 K 50 kW 40,000 m2 6,000 m2 A variety of types of plastic sheet, as well as glass, were selected in order to establish which was the best - and in the long term, most cost effective - material. It was found that glass is able to withstand even severe storms over many years without damage and proved to be self-cleaning occasional rain showers were sufficient. Completion of the construction phase in 1982 was followed by an experimental phase, the purpose of which was...

Geothermal power generation

Geothermal power production has a relatively long history. Just 38 years after the invention of the electric power generator by Werner von Siemens and 22 years after the start of the first power station by Thomas A. Edison in New York in 1882, geothermal power production was invented by Prince P. G. Conti in Lardarello, Italy in 1904. Geothermal power production in Tuscany has continued since then and amounted to 128 MW of installed electrical power in 1942 and to about 790 MW in 2003. In 1958,...

Gridconnected systems

Photovoltaic systems feed the generated electric energy into the power grid using inverters to adapt the direct current from the photovoltaic system to the characteristic of the mains (for examples see Table 6.2). The basic structure of such systems is illustrated in Fig. 6.27. Fig. 6.27 Roof mounted photovoltaic generator directly feeding into the public grid Fig. 6.27 Roof mounted photovoltaic generator directly feeding into the public grid In terms of grid-connection, the following concepts...

Heat pump

A heat pump - like any other technical system - consists of various system elements. In the following, they are primarily explained further for electrical compression heat pumps, as they have the highest market share (e.g. 9-1 , 9-2 , 9-3 , 9-12 ). It can be differentiated by the heat exchanger utilised in the evaporator and the condenser, the compressor, the expansion valve, the lubricant as well as the working medium (refrigerant). Heat exchangers. Heat exchangers are devices that transfer...

Info

Fig. 4.9 Energy conversion chain of solar thermal heat utilisation (e.g. 4-6 ) Fig. 4.9 Energy conversion chain of solar thermal heat utilisation (e.g. 4-6 ) Losses. Due to the various loss mechanisms only part of the solar radiation is available as heat to the consumer. Fig. 4.10 shows the energy flow of a solar thermal installation with a flat-plate collector, forced circulation and one to two day storage to support the domestic hot water supply for a private household of 3 to 5 people...

Introduction and Structure

The aim of this book is to outline and discuss the main fields of renewable energy applications, and thereby create a solid basis for their evaluation. For this purpose, both the physical foundations and the technical bases are presented. Additionally, key figures which allow for a classification of these options according to the demands of the energy system are elaborated. To ensure a simple, comprehensible and transparent presentation of the different options of using renewable energy for the...

LS

Lubricant 382, 410, 412 lubricant loss 379 luminous reflectance 345 luminous spectrum 125 magma chamber 470 magma deposit 96 magmatic body 470 magnetic field 293, 314, 315 magnetic induction gauge 73 magnetic valve 419 majority carrier 232 malfunction 194, 293, 347, 462 (MWD) 440 mechanical brake 313 mechanical deterioration 258, 327 mechanical efficiency 326 mechanical energy 2 mechanical energy 323, 351, 370 mechanical failure 348, 382 mechanical loss 325 mechanical power 295 mechanical pump...

Parabolic trough power plants

The line focussing solar fields of parabolic trough and linear Fresnel collectors reflect the incident radiation on an absorber positioned in the focal line of the concentrator. The collector tracks the sun in one axis (Fig. 5.14). Due to this one-dimensional concentration the geometric concentration factors of 15 to 30 are considerably lower than those of two-dimensional collectors discussed above. This is why lower temperatures are achieved when compared to solar tower power plants. However,...

PH y

I stands for the current flowing through the terminals, lPh for the photocurrent and I0 for the saturation current of the diode, whereas e0 represents the elementary charge (1.6021 10-19 As), U the cell voltage and k the Boltzmann constant (1.3806 10-23 J K), and 6 stands for the temperature. However in Equation (6.1) the sign for current I have been inverted compared to the conventional notation. This is why the characteristic curves (Fig. 6.7) are not located in the forth but in the first...

Photo effect

The term photo effect refers to the energy transfer from photons (i.e. quantum of electromagnetic radiation) to electrons contained inside material. Photon energy is thereby converted into potential and kinetic energy of electrons. The electron absorbs the entire quantum energy of the photon defined as the product of Planck's quantum and the photon frequency. External and internal photo effect is distinguished. External photo effect. If electromagnetic radiation hits the surface of a solid body...

Photovoltaic cell and module

Fig. 6.6 shows the basic structure of a photovoltaic cell consisting of p-conducting base material and an n-conducting layer on the topside. The entire cell rear side is covered with a metallic contact while the irradiated side is equipped with a finger-type contact system to minimise shading losses. Also full cover, transparent conductive layers are used. To reduce reflection losses the cell surface may additionally be provided with an anti-reflecting coating. A silicon solar cell...

Photovoltaic effect

If photons, the quantum's of light energy, hit and penetrate into a semiconductor, they can transfer their energy to an electron from the valance band (Fig. 6.5 e). If such a photon is absorbed within the depletion layer, the region's electrical field directly separates the created charge carrier pair. The electron moves towards the n-region, whereas the hole moves to the p-region. If, during such light absorption, electron-hole-pairs are created outside of the depletion region within the p- or...

Preface

The utilisation of renewable energies is not at all new in the history of mankind renewable energies have for a long time been the primary possibility of generating energy. This only changed with industrial revolution when lignite and hard coal became increasingly more important. Later on, also crude oil gained importance. Offering the advantages of easy transportation and processing also as a raw material, crude oil has become one of the prime energy carriers applied today. Moreover, natural...

Principles

Plants consist of the stem, leaves and roots. The latter anchors the plant in the ground and enables it to withdraw water and nutrients from the soil. The stem carries the leaves, supplies the plant with water and nutrients from the root, and carries the organic substances generated in the leaves to the root. The leaves absorb the sunlight required for photosynthesis. They enable the gas exchange of carbon dioxide (CO2), oxygen (O2) and steam (H2O) for...

S

Hard coal and lignite Mineral oil Natural gas Other fossil biogenous energy carrier Energy manifestations and their effects Fig. 2.5 Energy sources, types and effects (see 2-7 ) Energy manifestations and their effects Fig. 2.5 Energy sources, types and effects (see 2-7 ) As the earth is almost in an energetic balance, the added energy has to be balanced by a corresponding withdrawal. This energy balance of the earth is shown in Fig. 2.6. The very largest part of the energy converted on the...

Sn

Fig. 6.16 Connection of solar modules inside a photovoltaic generator 6-10 However, experiences have shown that neither bypass diodes within the individual cell strings of a module, nor blocking diodes at the end of a module are required. These kinds of safety measures create increased energy losses and thus increased costs. Furthermore, diodes show a shorter technical lifetime than cells and modules. However, the case is different if several modules are connected to larger units (arrays, array...

Solar Thermal Power Plants

The term solar thermal power plant comprises power plants which first convert solar radiation into heat. The resulting thermal energy is subsequently transformed into mechanical energy by a thermal engine, and then converted into electricity. For thermodynamic reasons high temperatures are required to achieve the utmost efficiency. Such high temperatures are reached by increasing the energy flux density of the solar radiation incident on a collector. In this respect, we refer to concentrated...

Structure and procedure

Due to the great variety of possibilities to use renewable energy sources with the aim to fulfil the demand for end or useful energy, it is very difficult to present the different possibilities in a similar manner. It is thus highly important to explain the different utilisation methods in a flexible manner. Therefore the basic procedure of addressing the various options is outlined in the following. Furthermore, the main terms on which the respective explanations are based are defined. The...

Supply characteristics

In order to be able to measure short and long-wave radiation fluxes through the atmosphere, a number of different measuring instruments are available. Relative and absolute instruments are generally differentiated 2-3 , 2-10 . If radiation energy has to be measured in absolute terms, the incident solar energy has to be converted into a measurable parameter first. Most of these radiation measurement instruments thus absorb the radiation energy on a blackened surface which...

System components

The system elements composing parabolic trough power plants comprise collector, absorber, heat transfer fluid circuit and power block. Collectors. The collectors which are typically 100 m, but may nowadays also be 150 m long, are provided with single-axis solar tracking. The annual mean cosine losses of parabolic troughs vary between 10 and 13 , whereas those of Fresnel concepts are double. After deduction of the optical and thermal losses inside the collector 40 to 70 of the radiation incident...

V

Velocity of the air inside a chimney tube (tower) Maximum velocity of the air inside a chimney tube (tower) Velocity of a wind-blown surface (S) vwi, Wind velocity at reference point 1 vwi, 2 Wind velocity at reference point 2 vwi, a Wind velocity at a defined site (a) vwi, h Wind velocity at a defined altitude (h) vWii Wind velocity at reference point i vwi,North Wind velocity, northern hemisphere vwi, ref Wind velocity at a reference altitude (href) vwiRot Wind velocity within the rotor level...

Nsa

Wind power exploitation aims at extracting the maximum share of wind power. Due to physical restrictions wind masses flowing through rotor level cannot be entirely slowed down, as a complete slowdown would clog the rotor and impede power extraction. On the other hand, wind velocity must be decreased if power is to be extracted from flowing air masses. Consequently, there must exist a certain ratio between the speed long before and far behind the rotor that corresponds to the maximum power...

Vvvv

Fig. 6.13 Layer deposition and structure sequence of a photovoltaic thin film module (a) deposition of the transparent front electrode on the glass superstrate b) first structuring step c) deposition of the photovoltaic active absorber layer d) second structuring step e) deposition of the rear electrode f) third structuring step) Solar cells for concentrating photovoltaic systems. Solar cells of concentrating photovoltaic systems are illuminated up to 500 times more at standard test conditions...

Ktq

A Single family house (SFH-I) with low-energy design b single family house (SFH-II) according to current heat insulation standards, c single family house (SFH-III) as an old building with an average heat insulation, d multi family house (MFH) for the definition of SFH-I, SFH-II, SFH-III and MFH see Table 1.1 and Chapter 1.3 respectively. a Single family house (SFH-I) with low-energy design b single family house (SFH-II) according to current heat insulation standards, c single family house...

Gridindependent applications

The majority of all individual wind turbines and wind parks are connected to the power grid. However, there is also a multitude of grid-independent and winddiesel systems designed for small power grids which are outlined throughout the following sections. Wind-battery systems. In most cases, grid-independent wind battery systems are small capacity wind turbines which, coupled with a battery and a battery charge regulator, supply one or several power consumers. The nominal capacities of the...

Further system components

Solar generators as well as battery storage systems principally deliver direct voltage or direct current (DC). Many small appliances (such as watches and calculators) are designed for DC supply. However, most appliances require alter nating current (AC) of 230 V and a frequency of 50 Hz (in some cases 120 V at 60 Hz, as in the US, for instance). Even, for stand-alone photovoltaic systems without grid-connection, frequently inverters are used to convert direct current (DC) into the...

Overall systems

Free Energy From Air

Heat source systems (Chapter 9.2.1 and 9.2.2) and heat pumps (Chapter 9.2.3) are integrated into overall systems that enable the utilisation of ambient air or shallow geothermal heat as end and useful energy respectively. Therefore firstly typical system configurations for characteristic applications are described. Afterwards system aspects of such overall systems will be discussed. System configurations. In the following, a heating system with exhaust air heat recovery and exhaust-air to...

Idealised wind energy converter

The considerations outlined throughout this section with regard to assessing the theoretical total capacity extractable by means of wind energy converters (such as a rotor) are based on the following ideal conditions and assumptions - frictionless, stationary wind flow, - constant, shear-free wind flow (i.e. wind speed is the same at every point of the energy extracting surface (e.g. circular rotor surface SRot) and flows into shaft direction), - rotation-free flow (i.e. no wind deviation into...

So

Fig. 6.25 Schematic of a photovoltaic system for supply of a direct current load or direct current consumer application (PV photovoltaic generator, DC direct current) Fig. 6.25 Schematic of a photovoltaic system for supply of a direct current load or direct current consumer application (PV photovoltaic generator, DC direct current) Photovoltaic systems, applied, for instance, for household or small consumer supply, generally consist of a solar generator, a charge controller and an energy...

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...

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...

Utilisation of Ambient Air and Shallow Geothermal Energy

Diagram 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...

Plant concepts

Solar Pond Power Plant Diagram

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...

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 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...

Drag and lift principles

Lift And Circumferential Force Airfoils

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...

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

Solar Updraft Tower Circuit Diagram

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...

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.

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

Updraft Tower Plant

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...