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

In Central Europe, heat pumps for space heating and domestic hot water generation are mainly built as monovalent compression heat pumps driven by an electric motor. The following analyses will deal with systems that can cover various supply tasks (three single family houses with different types of insulation (SFH) and one multi-family house (MFH) see Chapter 1.3) - in each case with a different heat demand (Table 9.7). For that reason, system configurations of heat pump systems with direct...

Economic and environmental analysis

Within the following sections the specific power production costs and selected environmental burdens are explained and discussed for state-of-the-art grid connected photovoltaic generators. Yet, the economic and environmental assessment of stand-alone photovoltaic systems is much more difficult and largely depends on the respective site conditions. For instance, the economic and environmental parameters of hybrid systems are largely influenced by the distribution of the generated power among...

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...

Environmental analysis

For the systems utilising ambient air and shallow geothermal energy analysed so far (Table 9.7) a number of selective environmental parameters are discussed below occurring during construction, normal operation, in the case of an accident and at the end of operation. Construction. The environmental effects caused by installing a heat pump system for ambient heat utilisation are mainly due to the use of water as a heat source and, for ground probes, sinking the boreholes. Potential environmental...

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...

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

On some days, the diurnal course of the wind velocity can deviate significantly from the mean diurnal course given in the yearly average due to changing local weather conditions. However, in the course of one year, stationary weather conditions generally prevail. The diurnal course exemplarily described for the site of Norderney Germany is equal to the diurnal course at a thermal stratification during robust weather conditions, with a strong mixing of the air layer close to the ground during...

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,...

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...

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...

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...

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...

System components

Free Energy Collector Components

In the following, the individual components of such a power plant are presented and discussed. Collector. The hot air required for the operation of a solar updraft tower power plant is created by a simple air collector. The latter consists of a horizontal translucent glass or plastic roof located approximately 2 to 6 m above ground (Fig. 5.27). The translucent roof is permeable by solar radiation, but impermeable by the long-wave heat radiation emitted by the collector bottom, which is heated...

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...

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...

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...

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...