Due to the increasing energy monetary values and worsening energy resources it becomes more and more of import to utilize alternate energy supplying solutions. Harmonizing to the Kyoto protocol and the clime alteration conference in Copenhagen that at the minute discuss the most of import industry states associating to the environment and economic system about the inquiries: How to cut down the green gas emanations and how to cut down the ingestion of stoping fossil energy beginnings? The most of the states have the sentiment that the current major portion of our energy usage beginnings is limited and that we have to alter our blowing devour behavior. A batch of politicians and scientists think that our following power beginning solution is in renewable energy like air current, H2O flow and H2O degree energy, solar, bio fuel and geothermic energy. At the minute planetary ingestion of renewable energy is about 14 % . The biggest portion of the renewable energy ingestion is bio fuel of 13,6 % Erneuerbare Energien-politik Bernd Hirschl, 2007, Page 422 The Technology to utilize air current, H2O, Sun and geothermic energy is really expensive and it is non really profitable, because the monetary value of the dodo fuel, although it is steadily turning, is still excessively low to utilize the alternate energy. But the authoritiess know that the world will perfectly trust on the renewable energy in the hereafter. Hence they support with investings and subsidies the renewable engineering developments and undertakings. Germany for illustration spends one million millions for subsidies for solar energy workss. Harmonizing to Dr. Klaus Peter Krause “ it was a entombment of one million millions and it causes a gold-rush temper since 2004. This must be stopped ” . Many people have similar sentiment. ( Die Freie Welt, Solarstrom das Milliardengrab, 23.04.10 ) At the minute 9 different European states under it Great Britain and Germany are be aftering a 30 billion euro undertaking. This undertaking includes the usage of different types of renewable energy. The web is supposed to link air current turbines in Scotland, solar panels in Germany and beckon power workss in Belgium and Denmark. ( Klima Wandel, Sonne, Wind und Wellen Nordsee ALSs Kraftwerk, 07.01.10 ) Due to the immense outgos for the renewable energies and the for good looking critic from scientists and media it is of import to happen out whether the behavior of our politicians is justifiable.
The renewable energy is of import for our hereafter but the renewable energy is really expensive. For that ground we have to see, what sort of renewable energy we have to put to. The media and politicians are speaking about different types of renewable energy, but there is one promising sort of energy usage cipher is speaking about. Harmonizing to DWA-Regelwerk Merkblatt DWA-M 114 Energie gold Abwasser – Warme und Lageenergie, Juni 2009 the heat energy in German sewerages has the possible to provide 10 % heat energy to the German lodgings.
Every twenty-four hours a batch of waste H2O flows through the sewerage system. The liquid waste gets filtered in the sewerage elucidation works and runs to the terminal of the receiver. This H2O is polluted and hence chiefly considered as waste without any economic value. However the wastewater of private family, agricultural and industrial companies does non merely reassign waste. During this transportation procedure heat is besides generated. Hence the streamlined H2O has a higher temperature than for illustration imbibing H2O. So it should be considered to utilize the energetic warming potency of the sewerage for providing heat to the local family. Effluent is accordingly a possible resource for a thermic advantage.
The renewal of the energy occurs with a recuperator. It consists of a liquid medium which removes the energy to a heat pump. The heat pump converts the low temperature of a immense sum of liquid to a higher temperature of a smaller sum. So with that status the het H2O can be used for warming the houses and tap H2O.
The engineering of repossessing thermic energy in canalisation is proved. There are already some workss in operation since many old ages in Switzerland and Germany. But similar workss in Great Britain could n’t be found. The heat money changer produces energy, saves primary energy resources and reduces CO2 emanation. So should this engineering besides be used in Great Britain?
Purposes and Aims
The purpose of this undertaking is to happen out: Is it sensible to construct heat renewal workss compared with another types of renewable energies in Great Britain? In the 2nd chapter the Energy political relations in Great Britain will be discussed to clear up the necessity of renewable energies. In the beginning of this chapter it will be indicated to the energy jobs and what aim the authorities of this state is traveling for. In the following measure the political agreements will be mentioned and how the state has developed to make the energy purposes. Afterwards the energy production and ingestion of Great Britain will be described to understand the energy state of affairs and the demand for a alteration in the consumer behavior of this state.
In the 3rd chapter the engineering of a heat renewal works in sewerages will be explained. The purpose of this chapter is understand how such a works can be used and what topographic points are more appropriate to put in it. Furthermore this chapter will specify which proficient and practical attempts are necessary, which costs are required to construct such a installation, how much energy such a system can bring forth and how much money can be saved. For the possible estimations of the works must be considered the proficient demands of the sewerage system and heat money changer every bit good as the demands of client and supplier. Besides the sewerage system provider has to be researched, which uses the system as drainage. Main responsible company for the canalisation system in West Midlands is Severn Trend Limited.
Even though it is proved that such a works can bring forth energy, there are many things to discourse about the efficiency of that engineering. There are a batch of different engineerings to utilize clean and renewable energy e.g. air current, solar, tidal, hydro, bio fuel power a.s.o. So in the 4th portion it has to be discussed which renewable energy is more profitable? The heat power of sewerage systems engineering is really new and there are non really much informations about the profitableness. After comparing all the bing workss in the sewerages the current efficiency and the possible capacity in the hereafter of all renewable engineerings, and after comparing of the profitableness and sustainability of the bing and planned renewable energy installations, we can presume the necessity of utilizing the waste H2O energy.
Even if such engineering exists in Germany and Switzerland, it does n’t intend that it is sensible to construct it in Great Britain. So in the 5th portion it has to be compared the attitude to the energy policy, ingestion and energy necessity of these states. Most states recognise the exigency to help the renewable energy. Hence the authoritiess try to subsidise the advancement of modern developments. So this work will depict the current subsidies policy in Germany and Great Britain and discourse whether it is sensible to back up the heat pump engineering of sewerages in UK. ( Andre Suck, Erneuerbare Energien und Wettbewerb in der Elektrizitatswirtschaft, staatliche Regulierungen im Vergleich zwischen Deutschland und Gro?britannien, 2008 ) . Furthermore it has to be compared whether the difference of energy monetary values or the energy ingestion for the heat energy of Germany and UK can be a ground non to utilize the heat energy in Great Britain.
The following chapter will demo the practical usage of a heat renewal works within a British metropolis Coventry. It will demo some countries of the sewerage system and depict why they are appropriate for a works. In that portion all the information of the work has to be used to happen a proper topographic point and what sort of advantages the peculiar pipes have. The purpose of this chapter is to demo that it is possible to construct that works in Coventry and so in many other metropoliss.
The last chapter is a decision whether the engineering is appropriate to utilize it in Great Britain under the comprehension of the mentioned positions: Energy policy of Great Britain, Energy production and ingestion, technological demands and energetic end product of the energy renewal installation and the practical usage in the bing sewerage system.
Energy political relations in Great Britain
Dependence: Although Europe and Great Britain is economically and politically really strong power, the state is still really dependent on the resources of other states.
Harmonizing to Bundesanstalt fur Geowissenschaften und Rohstoffe and US Department of Energy Great Britain has about no available oil militias within inland.
Global scarceness of Resources: Another job is the energy supply in the hereafter. The chart diagram of Ochsner in the Book Geothermal Heat pump shows that the chief natural energy beginnings will be over in the following two centuries. So there must be found other types of power for the following coevalss.
Sustainability means the development possibilities should be constricted neither in the present nor in the hereafter. An of import factor for the sustainable handling with the resorts is the proficient advancement. The development of advanced energy usage engineering increases the energy efficiency, extends the usage period of limited beginnings and reduces the environmental pollution. ( Sustainable energy, taking among options, Jefferson W. Tester 2005 )
The firing procedure of gas coal and oil releases different sort of toxic gas in the ambiance. ( e. g. C dioxide, methane, chloroflourocarbons, Ground level ozone and upper atmospheric H2O vapour and azotic oxide ) . These gases cause the nursery consequence and clime alteration. ( Ochsner in the Book Geothermal Heat pump 2007 ) United Nation surveies ( Intergovernmental Panel on Climate Change study February 2007 ) claim that the environmental pollution will do an mean temperature addition in the following 100 old ages from 1,5-6A°C. This clime alteration can be a dramatic danger for the whole human sort. Additionally accidents and edifice effects much pollution during the extraction and transit of the stuff.
Energy is necessary for everybody in normal class of life and for the growing of the economic system in a state. Energy ingestion has to cover with two challenges in the hereafter. Manage the clime alteration by diminishing the C dioxide end product within inland and abroad and guarantee clean, save and inexpensive energy and go independent of the imported energy. ( HM energy, Meeting the energy challenge, a white paper on energy 2007 )
The purpose of our energy politic is the security of supply, efficiency and environmental friendliness. The Oil crisis showed that safeguarding of the energy providers is the most of import purpose. A supply warrant can be increased within a variegation of energy resorts and so a variegation of energy provider. The importance of renewable energy beginnings increases because planetary energy demands rise, handiness of fossil fuel, crude oil and gas is limited. Consequently in the long term it is required to replace limited for renewable power. Environmental protection has two demands. First to cut down the scratch of environmental stuff like wood, crude oil, fuel and secondly to cut down fouling emanation like CO2, which occurs by coevals of energy. ( Weltvertragliche Energiesicherheitspolitik, Josef Braml 2008 )
The clime alteration act 2008 has the mark to cut down the emanation of nursery gases of 80 % until 2050 compared with the twelvemonth of 1990. The short term aim of the CCA 2008 is to cut down the CO2 emanation of 26 % until the twelvemonth 2026. In the EU ‘s Renewable Energy Target and the alteration of the Emissions Trading System: Follow-up study is written, that EU has the mark to utilize 20 % renewable energy of the full ingestion in the twelvemonth 2020. Harmonizing to Lord Hunt Commissions suggestion to make 15 % is realistic. The country of West Midlands and of class the industry metropolis Coventry has the duty to do a part to that duty.
Department of Business Enterprise and Regulatory Reform wrote in the “ UK Energy in Brief July 2007 ” , that from 1980 boulder clay 2004 UK imports of rough oil and crude oil are used to be smaller than the exports. But since 2004 in Great Britain the imports exceeds the exports. So Great Britain becomes more and more dependent by merchandises from other states.
United Nation Framework Convention on Climate Change found out that Britain reduced the emanations the greenhouse-gas emanations between 1990 boulder clay 2007 by about model 18 % . Compared with other states has Great Britain besides Russia and Germany the best betterments worldwide.
To sum up the energy and environmental political demands, the security of energy supply is an of import factor now and in the hereafter. It is necessary to pursuit variegation scheme refering energy medium and provider. Especially renewable engineering is really good to conserve the energy resources and to cut down the emanations. That engineering can besides avoid large energy monetary value fluctuation in the hereafter.
Energy Production and Consumption
Energy is in different signifiers in the nature available. It is non possible to utilize all energy signifiers straight. It is a procedure required to reassign the primary energy ( e.g. rough oil, coal, natural gas, U and regenerative energy beginnings ) in ingestion energy ( e.g. warming, electricity, fuel oil ) . The transmutation and transit causes a batch of energy loss. After the ingestion all the private families loose the energy through the heat dissipation to the exterior, inefficient burning and dissipation of waste H2O.
Harmonizing to Elissa Minosi ( Klimapolitische Richtlinien der EU und nationale Umsetzung in Deutschland und Gro?britanien 2009 ) energy production in United Kingdom diminutions and the energy ingestion slopes. Great Britain still depends to 98,7 % on non-renewable energy beginnings of primary energy ingestion. Other energy bearer like biofuels, wind hydro etc. bring forth merely 1.3 % .
The statistics show that UK attempts to utilize different sort of renewable energy beginnings but it does n’t utilize the heat energy of sewerages.
The current state of affairs shows that Great Britain has n’t reached the energetic marks. Refering to the energy policy purpose to unsure the energy supply and to utilize different primary energy signifiers, we have to acknowledge that UK still depends largely on limited beginnings. The portion of renewable energy is undistinguished. Harmonizing to United Nations Framework Convention on Climate Change Britain improved the nursery gas emanations really good. So they will likely make the aim to cut down the emanations of 26 % until the twelvemonth 2026. But there is still really much to make to cut down the emanations of 80 % till the twelvemonth 2050. All in all there is still need for action and the energy supply has n’t changed since the oil crisis for 30 old ages. The energy demands are increasing. The inland energy production goes down. So UK is even more dependent on imports. In the current treatment one suggestion can be found. Is it possible to utilize the heat energy in the sewerage system?
Appraisal of blowing Energy in the Sewage System
In the beginning we try to happen how much energy use British people for waste H2O and we perchance can utilize. Office of national statics says that about 48,5 1000000s of metric tons of oil equivalent are used for British families in one twelvemonth. The undermentioned graph shows that 11 % of lodging energy is used for hot H2O like shower, dish lavation and bath, what goes about by 100 % to the sewerage system. 48,5mill ten 0.11 = 5.3 factory. So it is estimated that 5.3 factory dozenss of oil are traveling into the British canalisations. In Coventry live about 300 thousand people and in Great Britain live 61 million people. So Coventry wastes about up to 26 000 dozenss of oil for the canalisations.
Basic rules of Heat Energy Reclamation
Different types of utilizing sewerage energy
There are three different types of utilizing the heat energy of waste H2O.
In the edifice
In the sewerage system before the intervention works
In or after the intervention works
In the undermentioned strategy advantages and disadvantages of different types of workss are listed. A renewal works in the intervention installation but before the elucidation is a intercrossed installation. The in-house heat renewal is non a portion of the sewerage system, so it is non in this work included. Basically the heat renewal is merely sensible if there is a large sum of waste H2O or high temperatures available. Buildings with immense H2O ingestion for illustration indoor swimming pools, secondary schools and industrial constitutions are appropriate for that usage.
In the edifice
comparative high waste H2O temperature
really short heat transit distance
energy provider is energy consumer
independent managing from sewerage system
no influence of the rainfall
low H2O flow
large timed fluctuation
riotous content in the waste H2O
small works with high attempts
In the sewerage system
immense waste H2O sum
short and medium heat conveyance distances
supervision of the works
alteration of waste H2O and pipes conditions
In or after the intervention works
no influence to the H2O elucidation
immense and changeless H2O sum, so the biggest possible energy supply
waste H2O is purified
chilling of the H2O, so no influence of the receiver
intervention workss are really frequently far from the lodgings, so there is a long heat transportation distance
dependence of the sewerage intervention works runing company
Functionality of a thermic energy utilizing works
A recuperator will be installed in the sewerage channel that. Liquid medium circulates in the heat money changer and takes out a portion of the energy of the waste H2O. The het medium will be transported to the heat pump. The heat pump warms with this energy H2O to a higher temperature, what can be used for heating the lodgings or tape H2O. The cooled liquid goes back to the sewerage channel and the rhythm begins once more. The power energy is important lower than the end product of the pump. This system can be besides used for chilling of edifices. But it is non the chief mark of this work.
Heat money changer:
Heat money changer is the beginning of the energy usage rhythm. The end product W ( kilowatt ) of the HE is dependent from the surface of the money changer A ( mA? ) , the in-between temperature difference between the money changer stuff and the waste H2O I”T ( K ) and the heat exchange coefficient k. The heat exchange coefficient depends on the opposition, what the heat exchange applies to the flow. So it depends on the money changer type and flow conditions of the medium.
Mathematical equation: W=k*A*I”T
The affectivity of the money changer can be besides influenced by the fouling factor degree Fahrenheit ( W/ ( mA?*K ) ) . This factor has to be considered, because an organic coat can happen over the clip, which can cut down the affectivity up to 50 % . So it might be required to clean the money changer. Additionally the flow rate or the incline influences the end product of the HE, because large flow rate has a little contact clip between the medium.
( Fouling in heat exchange equipment, Suitor and Pitchard, 1984 )
( Warmetauscher, Podhorsky Miroslav, 1999 )
A heat pump consists fundamentally of an evaporator, compressor, capacitor and enlargement valve. The medium with a low furuncle point will be heated in the vaporization measure and the liquid becomes a gas. Hence the medium in the evaporator is in a low force per unit area and the temperature exterior is higher than indoors. The temperature difference causes a heat transportation and the medium evaporates. At the 2nd measure the gas will be sucked and compressed. Compaction increases the temperature to a higher point. The heat pump needs normally electrical runing power, which of class must be lower than the usage energy. In the 3rd measure the medium goes to the capacitor where the medium is circulated with the warming medium. The temperature of the warming medium is lower, so the gas gets cold and liquid once more. The energy in the evaporator plus the captive electric energy from the compressor gets released in to the colder heat H2O. So the energy goes to a intent like room warming or tab H2O. And after the condensation the medium has to go through the enlargement valve, the temperature and imperativeness gets same before the evaporator and the rhythm begins once more.
There are two different ways to utilize the heat pump in a sewerage system. Monovalent usage means merely the works serve the energy to the lodgings. This is normally used in the geothermic energy, because the temperature of the energy beginning is changeless over the twelvemonth. Bivalent usage means the installation supplies most of the energy but in the coldest yearss added oil or gas warmer supports the heating. This type should be used in sewerages because the temperature fluctuates over the twelvemonth.
( Regenerative Energietechnik, Viktor Vesselak, Thomas Schabbach, 2009 )
Heat conductivities connect heat money changer with the heat pump. The conductivities have to be every bit short as possible to maintain the cost force per unit area and heat loss down.
Heat pump is a devise, which transfers the heat from low temperature medium with added runing power to a medium with higher temperature. Hence an efficient usage of a heat pump is dependent of the heat pump temperature. Waste H2O has normally a changeless minimal temperature degree over the twelvemonth. Therefore it is a sensible possibility to see about the heat renewal. The waste H2O has besides in the winter, when is the highest heat demand, compared with land H2O or lakes comparatively high temperatures.
There are two grounds for the high temperatures in the sewerages. First ground is our H2O we use in the edifices ( e.g. shower, cookery, wash, dish H2O, tab H2O, blushing H2O ) has really high temperature and full waste H2O goes to the sewerages. The waste H2O can be cooled down by the temperature of the sewerage system pipes and the rainwater, which flows into the system. Therefore pipes with pure waste H2O from the edifices are more appropriate for the renewal. In the winter the air temperature can be below 0A°C but merely the melted snow above 0A°C can get into sewerage pipes. Therefore the assorted sewerage H2O ( waste H2O and surface H2O ) has even in the winter really adaptable temperatures. There is a 2nd ground for the high temperatures besides the warm waste H2O. The sewerage pipes are largely built under Earth ‘s surface. In the winter temperature under the surface is higher than the temperature of the air. The temperature under the deepness of 2 metres varies even in the winter between 7A°C and 13A°C. For that ground the Earth surface works like heat insularity for the waste H2O.
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The sewerage channel transports heat energy and is accordingly an interesting beginning for the energy supply. But the effluent intervention works operators have a demand non to fall below 10A°C and the waste H2O must non chill down more than 0.5 Kelvin. No job will happen, if these two conditions are satisfied. Normally the temperature is even in the winter between 10-15A°C A?
( Schriftenreihe aus dem Institut fur Rohrleitungsbau Oldenburg, Rohrleitungen-Unternehmen im Aufbruch, Band 12 )
The undermentioned image shows a surface of a manhole screen, what the most people have already seen, but seldom person give attending to that fact. The heat energy of the sewerage warms the manhole screen and the snow is melted. I means that the temperature in the channel is at least 0A°C
Existing workss in Switzerland
In the following chapter some different workss in Switzerland will be introduced to turn out the functionality and profitableness of heat usage works. It seems that Ryser Ingenieure AG is a Swiss cutting-edge company in that concern.
Existing workss in Switzerland:
Existing workss in Germany
Since 2001 supplies the Warmeversorgung Binningen AG 61 Buildings with 300 flats with differen use e.g. School, City Council and private lodgings with about 4.800 kW power. Stallion costs for the heat renewal works are 700.000 a‚¬ .
The chief heat supply comes from the Heat pump with usage of the local sewerage pipe, with the distance of 70 m heat pump from the pipe and two heat power Stationss of BHKW. For peak tonss in really cold yearss or in the instance of a interruption down there are common gas and oil warming boiler available. Vgl. Dietler, M. EBM, 2004
The most of import informations overview:
Apartment measure: 300
Energy production: 2.400 MW h/a
Power end product heat pump: 380 kilowatt
Length: 140 m
Width: 0,80 m
Area: 110 mA?
Power end product heat money changer: 260 kilowatt
Heat pump runing factor: 3,2
Specific end product of the heat money changer: 2.4 kW/mA?
Sewage type: assorted waste and surface H2O:
Flow rate: 200 l/s
Cooling in the canal: 0.3 CA°
Ryser Ingenieure AG
Heat money changer:
The heat money changer consists of about 50 interrelated elements 3 x 0.8 m. The elements have been installed on the floor of the egg shaped channel. The outgoing and return pipes are on the left and right side of the channel installed.
Surpassing and return pipes
Heat money changer elements
Provisory installed channel for the installing clip
Connection between the elements gets installed
Heat money changer elements with surpassing and return pipes entree gets installated
Vgl.EBM et Al 2002
So far realized analyses result a 3.2 heat pump runing factor. ( Vgl. Dietler, M/EBM, 2002 ) The heat pump supplies in the summer the full energy for the check H2O unto 70 A°C. In the winter linked power boiler supply the check H2O and the heat pump warms the suites in the edifices, because the heat pump works more efficient for lower temperatures than the tab H2O and the temperatures in the sewerages are lower in the winter.
Harmonizing to Ryser Ingenieure AG there were merely fringy upsets. It was even no diminution in the power end product, so a elucidation of the heat money changer and heat music director was n’t necessary. The sewerage operator had no added attempts for the system. There is no consequence to the map on the channel. The caused temperature difference for the intervention works of 0.3A°C is undistinguished.
Since 1999 supplies heat sewerage works 31 lodgings in Muri with energy. Stallion costs for the sewerage heat works is 108.000 a‚¬ and 62.000 a‚¬ for the heat boiler in the winter. Two heat pumps convert the waste H2O energy in the collection point in a intervention works into heat energy for edifices. A gas boiler supplies energy in the clip with the most demands. Tab H2O energy supply is decentralized in every edifice. The heat pump delivers 75 % of the full heat energy demand over the twelvemonth. The chilling waste H2O in-flow is less than 0.1 A°C
The most of import informations overview in Zwingen:
Apartment measure: 31
Energy production: 230 MW h/a
Power end product heat pump: 64 kilowatt
Length: 10 m
Width: 1,06 m
Area: 10.6 mA?
Power end product heat money changer: 52 kilowatt
Heat pump runing factor: 4.6
Specific end product of the heat money changer: 4.9 kW/mA?
Sewage type: assorted waste and surface H2O:
Flow rate: 130 l/s
Cooling in the canal: 0.1 CA°
Heat money changer consists of 4 prefabricated elements with 2.5 m length and 1.06 m breadth, so the full length is 10 m.
The pump heats the medium for the floor heating merely to 50A°C. For that ground the pump really efficient. The steps until now result that the heat pump works with the operating factor of 4.6. The applied scientists expected an operating factor of 5 but they could n’t make it because of the much soil in the heat money changer.
The heat pump operator has some jobs with the regularly looking soil. But the costs for that are undistinguished. It is even possible to spread out the heat money changer and accordingly the end product because of the edifice technique of several elements.
Since 1994 supplies a heat sewerage works 200 flats with energy. The costs for the installation are 2.6 million euro. The competitory energy monetary value is 5.6 Ct/kWh. The costs for the full undertaking are so high, because of the large heat conductivity web and seven heat pumps.
The energy will take from the purified waste H2O in a intervention works and transported through the 3.2 kilometers long hosieries in cold status to 7 different decentralized bivalent warmers. Each warmer has a heat pump to provide the chief portion of the energy supply and an oil boiler for the immense energy demands. This installation supplies the whole energy over the twelvemonth.
Overview of the sewerage heat web in Muri
Beginning: Ryser Ingenieure AG
The most of import informations overview in Muri:
Apartment measure: 200
Energy production: 1700 MW h/a
Power end product heat pump: 1050 kilowatt
Power end product heat money changer: 700 kilowatt
Heat pump runing factor: 3.0
Operation: The medium of the heat money changer reaches 6-15 A°C. The works supplies besides in winter energy. The energy will used for heat energy. The maximal temperature of the warming medium gets from 50 to 60 A°C. The heat pumps deliver 66 % of the full warming energy needs the remainder delivers the oil boiler. The works saves 300.000 litres in one twelvemonth and about 750 dozenss CO2 emanations. The Heat money changer will be cleaned twice in one twelvemonth. One cleansing takes half of the twenty-four hours. The pollution of the heat money changer is really rare because the heat supply medium is already clarified.
These illustrations proof that a elucidation works can be installed in already bing sewerage system and it can present immense energy beginnings for 100s of flats. The illustration of Muri shows that a sewerage renewal works is even with really bad conditions profitable and the energy can be transported for stat mis. All the workss have to be maintained but the costs for one or two times in a twelvemonth of the heat money changer elucidation and the chance of failure seem to be fringy.
The illustrations in Switzerland and Germany proof that the heat energy renewal in sewerage pipes work. At the minute there are many different tested and proofed types of renewable energy in usage. All these constitutions produce utile energy for heating and electricity. The undermentioned chapter will depict the most import renewable energy engineering.