Category Renewable Energy

An Exceptional Sustainability Concept

by Christian Matt | Matthias Schuler

Подпись: Fig. 1 The new group home of the Deaconry Stetten with a sustainable energy concept (photo: © Lahoti & Schaugg, Esslingen-Stuttgart).

This example of a German therapy center including residential accommodation shows how an intelligent concept is capable of cleverly joining ecology and economy. Furthermore, the combined biofuel and cogeneration unit of the neighboring farmer makes even the heating largely autonomous.


he architectural office of Michel, Wolf and Partners (Stuttgart, Germany) has developed a complex of build­ings in cooperation with Transsolar Energietechnik GmbH (Stuttgart) featuring an exceptional energy concept. It emerged from an old mansion in the Bergheim district to the northwest of Stuttgart. The plan was to renovate this villa so that it would accommodate a therapeutic institution for a group of just under 40 handicapped people...

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Aquifer Reservoirs for Energy Management – Reichstag and Neubrandenburg

In the construction and the energy management of the new government buildings along the River Spree in Berlin, future – oriented, environmentally responsible and exemplary en­ergy concepts were required [2]. The energy-supply sys­tem of the Berlin parliament buildings therefore contains, along with components for combined heat-cooling-power production, two aquifer storage reservoirs (Figure 2). The heat storage reservoir increases the contribution of the com­bined heat and power plant to the overall energy supply, even when the system is power-directed. The cooling reser­voir permits the use of the low winter temperatures for air conditioning in the summer months.

The storage region is a sandstone stratum at a depth of 285 to 315 m which contains salty water (brine)...

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Today’s Standard Technology: the OWC

OWC is the abbreviation for Oscillating Water Column and describes a design which makes use of the wave motion in rising and falling water columns. Figure 5a shows how a typ­ical OWC functions. It consists of a chamber with two open­ings. One of these is on the side towards the incoming waves and lies beneath the water level. The water can en­ter the chamber through this opening, driven by the wave energy. The second opening allows the pressure to equal­ize with the surrounding air. The water column in the cham­ber moves up and down at the wave frequency, and thus “breathes“ air in and out through the second opening. This “breath” drives an air turbine...

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Electric Automobiles

by Andrea Vezzini


Подпись: !


Подпись: Charging device |2 High-voltage battery |3 Inverter with DC/DC converter to 12 V |4 Electric axle drive with separate motor-generator |5 Antiblocking system (ABS) / electronic stability program (ESP) 6 7 Cooperative regenerative braking system (Actuation control module - hydraulic (6) and brake operating unit (7)
Подпись: Renewable Energy. Edited by R.Wengenmayr, Th. Buhrke. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Electric cars indeed operate emission-free when the pow­er for charging their batteries comes from renewable sources (Figure 1). Even when their power is generated from fossil sources, they show a good C02 balance, since

they utilize the electrical energy very efficiently. Our mea­surements at the Bern University of Applied Sciences in Biel, Switzerland on an all-electric city vehicle, the Mitshu – bishi i MiEV, which has been on the roads in Europe since 2010, clearly demonstrate this. They showed a reduction of about 60 % in CO2 emissions compared to a standard mod­el with an internal-combustion engine, provided that the electric power was supplied entirely from a modern gas and steam combined-cycle plant.

The automobile industry has in the me...

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Power Transmission over HVDC Lines

By 2050, according to our scenario, transmission lines with a capacity of 2.5 to 5.0 GW each must be able to transport around 700 TWh of solar energy per year from 20 to 40 dif­ferent locations in the Middle East and North Africa to the major centers of consumption in Europe (Table 9), thus supplying ca. 15 % of the European power requirements. The cost of these imports is based on low production costs of ca. 0.05 12000-ct./kWh and a high flexibility for base-load, balancing power and peak-load operation (see below). Since our present AC grids would have overly high trans­mission losses at such high power levels and long trans­mission distances, it will be necessary to employ HVDC transmission lines...

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The Allure of Multicolored Images

by Michael Vollmer | Klaus-Peter Mollmann

Подпись: Building thermography using infrared cameras is becoming increasingly popular, since effective thermal insulation of buildings is in great demand. The gaudy false-colour images contain a great deal of information, but can easily be misin-terpreted by those lacking in knowledge and experience. We give an introduction to the technology and its tricks on the basis of selected examples. The technology of infrared imaging systems has developed rapidly since the mid-1990s. It has been driven by progress in microsystem technology, which has produced increasingly powerful detector arrays (sensors for infrared radiation) and read-out circuits. At present, a variety of camera systems for various applications are on the market [1]. They are used in many areas of technology and teaching [1-4]. For civil applications, IR cameras with megapixel detector arrays are already available. In recent years, much less expensive cameras with a smaller number of pixels have come onto the market. Typical of these are systems in the price range under 5000 1, with 160 x 120 or even only 60 x 60 pixels, and reduced software options. This is not surprising, since contact-free temperature measurement is an excellent instrument for analyzing e.g. the thermal insulation of buildings (Figure 1). image216"

In this field, the word “infrared” is often replaced by “thermal”, so that one usually speaks of thermal cameras and thermal images.

This basically positive development however creates some problems, in particular since the false-color images must be interpreted correctly. There are many traps lurking here, and we demonstrate some of them using examples. For this reason, several businesses and also the camera man­ufacturers offer training and certification courses on the fundamentals and applications of thermography [5]. To be sure, such courses cost as much as the less expensive cam­eras, so that some “services” dispense with the course and nevertheless offer thermographic analyses.

This is where the problem begins, as measurements ...

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Storage in a Field of Downhole Heat Exchangers

For the storage of thermal energy in a field with downhole heat exchangers (DHE), the underground strata also serve as the storage medium. Here, the reservoir is tapped by a number of boreholes of 20 to 100 m depth, usually sym­metrically arrayed, and these are outfitted with probes.

A geothermal field with DHE is an underground closed system in which there is no hydrological connection be­tween the storage medium (earth) and the heat transport medium. The heat transport for charging and discharging takes place through the walls of the probes. The charging and discharging thermal power is thus proportional to the

surface area of the probes and to the temperature difference between the thermal transport medium and the storage medium...

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Existing OWC Projects

Between 1978 and 1986, in an international experiment ini­tiated by Japan, an OWC system was tested for the first time on a large scale: The ship Kamai’ carried out three series of tests in the Japan Sea in which turbines with up to a megawatt of power output were installed. Only in 1998 was the idea of a floating OWC again taken up in Japan. The new Japanese prototype ’Mighty Whale’ however has a pow­er output of only 110 kW (Figure 2). An Irish group is cur­rently testing a reduced-scale floating construction at sea.

It has taken a similarly long time for the first continua­tion of coastal projects to be pursued, with an OWC of rel­atively high power output...

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