Stadtwerke Crailsheim

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1 Stadtwerke Crailsheim USING THE POWER OF THE SUN THE SUN IS THE MOST IMPORTANT SUPPLIER OF ENERGY: FREE OF CHARGE IT SENDS VAST QUANTITIES OF ENERGY TO THE EARTH. SUNLIGHT CAN BE USED IN MANY WAYS FOR INSTANCE FOR WATER HEATING OR SPACE HEATING. IN HIRTENWIESEN II THE STADTWERKE ARE USING SOLAR ENERGY TO PROVIDE 50 % OF THE RESIDENTIAL AREA WITH SOLAR HEAT.

2 TONS LESS CO2 PER YEAR PROVIDING APPROXIMATELY 50 % OF THE RESIDENTIAL AREA HIRTENWIESEN II WITH HEAT, THE SOLAR THERMAL SYSTEM SPARES THE ENVIRONMENT FROM ABOUT 1000 TONS OF CLIMATE-DAMAGING CARBON DIOXIDE (CO2) EVERY YEAR. FOR THE STADTWERKE CRAILSHEIM THE FLAGSHIP PROJECT REPRESENTS A MILESTONE TOWARDS A SUSTAINABLE SUPPLY OF ENERGY. When the sun is shining we are in high spirits and can t wait to go outside for a breath of fresh air. However, the sun offers much more than just good mood: The amount of energy provided by the sun every year is 80 times higher than the annual energy consumption in Germany alone. Besides: The sun is shining for free and doesn t cause any harmful substances. There are two ways of using the solar energy reaching the earth: firstly as photovoltaics converting the sunbeams into electric current and secondly as solar thermal system. Hereby the solar energy is converted into heat and used for water heating and as support of the heating system. Every year about 1125 kilowatt-hours of solar energy reach one square metre in Germany alone. The Stadtwerke Crailsheim make full use of this potential of the sun. By building Germany s largest solar thermal system in Hirtenwiesen, the Stadtwerke make an active contribution to environmental protection. The aim is to decrease the consumption of fossil fuels and to reduce the emissions of carbon dioxide. FUNCTIONING OF A SOLAR THERMAL SYSTEM IN A SINGLE-FAMILY HOUSE The solar collectors (1) are the core of the solar thermal system. Dark surfaces of sheet metal, copper or aluminium (the so-called absorbers) absorb the sunlight and convert it into heat. As soon as the temperature of the collectors exceeds the temperature in the storage tank, the solar control unit (2) will turn on the circulating pump. The recovered energy will then be delivered to a frost resistant carrier fluid transporting the heat through small pipes underneath the absorber (3) into the heat storage tank (4). A so-called heat exchanger (5) is located in the lower part of the heat storage tank. The heat exchanger transfers the solar heat to the drinking water stored in the heat storage tank. The heated drinking water goes up and flows into the domestic heat cycle (6). That way it can be used for taking a shower, washing and heating. In a second pipe (7) the cooled off carrier fluid flows back to the collectors and will be heated again. In case additional heat is required, there is a second heat exchanger (8) delivering heat from a heating boiler - thus allowing to have hot water available at any time. Further information on the solar heating system Hirtenwiesen and other projects of the Stadtwerke Crailsheim can be found on

3 3 EUROPEAN MUSEC PROGRAMME Through the new initiative MUSEC Crailsheim the Stadtwerke intend to press ahead with a sustainable supply of energy. In collaboration with local partners the utilisation of energy saving potentials as well as energy efficiency are to be improved. In addition the MUSEC Crailsheim wants to encourage the use of renewable energies and raise the public awareness with regard to energy consumption. MUSEC Crailsheim puts ideas into practice by specific actions at local level, e.g. the solar heating system in Hirtenwiesen II. The initiative was started in line with the European MUSEC programme. The name stands for Multiplying Sustainable Energy Communities an Europewide partnership for sustainable energies. For further information please visit: In the west of Crailsheim the new district Hirtenwiesen II has come into being. This part of town offers everything the heart desires for living: infrastructure with kindergarten, school, sports complex and shopping facilities surrounded by a beautiful landscape. However, Hirtenwiesen offers even more: modern and family-friendly living can be combined with an environmentfriendly way of life: With a collector surface of about square metres, the thermal heating system in Hirtenwiesen will be the largest one throughout Germany. As early as 2003 and 2004 the Stadtwerke Crailsheim installed the first 1040 square metres of solar collectors. The biggest part of the collector surface has been completed on the south side of the noise protection embankment recently. Since then the sun has been delivering approximately half of the required quantity of heat. The Stadtwerke s combined heat and power station produces the remaining heat by means of two heating boilers fired with environmentally compatible natural gas and one block-type thermal power station. Thus the heat gets into the house The green embankment doesn t only invite for a walk but also offers space for about 7500 square metres of collector surface. The solar control station first delivers the generated heat to the hot water storage tank and the buffer storage. From there each house is being provided with hot water through the local heat distribution network. For this purpose there is a heat transfer station installed in each house: A heat exchanger absorbing the heat from the local heat distribution network transfers the heat to the pipes for hot water and heating within the house. The water of the district heating system cools off and flows back to the hot water storage tank where it will be reheated. Due to the heat exchangers both in the local heat distribution network and in the individual households there is a closed circuit with little loss of heat. Environmentally friendly living The solar plant in Hirtenwiesen produces three million kilowatt hours of thermal energy a year. The solar assisted heat supply of the Stadtwerke reduces the demand for fossil fuels by about 50 per cent, thus diminishing the environmental pollution by 1000 tons of carbon dioxide and this every year!

4 4 Germany s largest solar thermal system will be built in Hirtenwiesen II inhabitants will then be provided with solar heat ADVANTAGES AT A GLANCE Active environment protection More room inside the house, as neither a storage room nor a boiler room is necessary Convenient and safe heat supply No need to acquire a conventional heating system Independent of price fluctuations on the fuel market Family-friendly living in the middle of nature Conservation of natural resources Flagship project for Crailsheim and its region OVERVIEW OF THE PLANT A total of 7500 square metres of collector surface will be installed on the south side of the noise protection embankment. The heat exchanger within the solar station makes it possible to use the solar heat for the supply of drinking water, heating water and hot water. Hot water storage tank: Approximately 500 cubic metres of hot water are stored in this first part of the long-term heat accumulator. The solar control station is located in the basement of the sports hall. It adjusts the heat supply and controls the optimum exploitation of solar energy. Buffer storage: Up to litres of hot water are being stored here temporarily. Borehole Thermal Energy Storage: The soil/rock absorbs the heat via geothermal probes and stores it from summer until winter (second part of the long-term heat accumulator).

5 5 HEAT SUPPLY THROUGHOUT THE WHOLE YEAR The sun delivers plenty of energy. Often much more than we can consume. A buffer storage and a long-term accumulator consisting of two parts store the heat in Hirtenwiesen also for the winter. The solar thermal system converts sunlight into usable energy. For this purpose the energy produced by the collectors is at first delivered to the solar control station located in the sports hall. The control station brings together the solar heat and the heat of the combined heat and power station. In addition it controls and adjusts the heat supply. Hot water being produced by a solar thermal system and not being required immediately, will be directed to the buffer storage and the hot water storage tank. The hot water storage tank has two functions: short-term heat storage facility and transfer station to the borehole thermal energy storage. Innovative the buffer storage The construction of the buffer storage is currently considered as unique throughout Europe. It has a volume of 100 cubic metres of water and serves for example During the day the buffer storage is collecting hot water generated by as short-term hot water storage solar collectors. tank for the night: It is composed of five rings made of concrete and lined with stainless steel to ensure watertightness. In the interior of the buffer storage the water is kept with a pressure of three bar. In order to make sure that the construction withstands the pressure, seven steel ropes inside the storage brace the cover with the base plate. Due to the high operating pressure the buffer storage works exceptionally efficiently. The pressure conditions make it possible to store the water up to a maximum temperature of 108 degrees Celcius. Thus this technology increases the efficiency of the storage tank by up to 15 per cent in comparison with a conventional system. During the night the buffer storage is delivering hot water to the supply network.

6 6 SUMMER (1) WINTER (2) Heat is stored Heat is released again Since the plant produces more energy than required, there are special heat accumulators storing the excess thermal energy of the summer for the winter. In Hirtenwiesen this is achieved through one of the largest heat accumulators in Germany a borehole thermal energy storage. Thereby it is very important to keep the heat loss as low as possible. Soil/rock is particularly well suited as it offers a large storage volume and keeps well the heat due to its density. How the heat gets into the soil/rock For the heat storage in Hirtenwiesen special pipes, so-called geothermal probes, were drilled 55 metres deep into the ground at a distance of 3 metres from each other. Then the solar-heated water is pumped into the geothermal probes through the hot water storage tank (1). The surrounding soil/rock absorbs the heat and stores it. During the winter the stored thermal energy is retrieved from the soil/rock and delivered to the supply network with the aid of heat pumps (2). Through this network the thermal energy is distributed to the connected homes using it for both hot water and heating. IMPRINt Stadtwerke Crailsheim Gmbh Publisher: screengallery - Die Medienagentur Friedrich-Bergius-Straße Schwäbisch Hall Crailsheim Germany Phone: +(49) Fax: +(49) info@stw-crailsheim.de internet: