With the fi rst oil crises in the beginning of 1970, the Swedish governmentinvested in, at that time, innovative technology using the underground asa source of energy for space heating. By developing these shallow geothermalsystems the goal was to decrease the dependence of oil.The result of these efforts is that some 25 % of the world’s total amount ofshallow geothermal systems is placed in Sweden. Today, heat and cold derivedfrom the underground is the third largest renewable energy source inSweden. It has been estimated that the shallow geothermal systems contributewith 11–12 TWh to the heat supply in Sweden.There is a lack of proper data for calculations of how much thermal energyis captured from the underground. Hence, the statistics shown in this reportare based on reasonable estimates, having the sales of heat pumps as aprime source of information.The Swedish Energy Agency chose not to report the domestic contributionfrom small-scale geothermal plants in Swedish statistics. Only the fi guresfrom the heat pumps in the district heating systems are reported. On theother hand in the statistic reports to EU, the Agency calculates with a significant amount from small-scale ground source heat pumps. This indicatesthat shallow geothermal should be more properly dealt with in the energysupply statistics.The geothermal storage systems are used for combined heating and coolingof commercial and institutional buildings, often in a large scale. Someof these systems are also applied to district heating and cooling as well asin some industries. The unique technology to store thermal energy in theunderground from one season to another makes a great positive impact tothe economy and to the climate.From an environmental perspective, shallow geothermal should be equivalentto solar energy and some other renewables. The electricity needed torun the plants should preferably be evaluated based on current directivesfor calculations of carbon dioxide emissions within each country.Shallow geothermal systems are most often reasonable profi table, lookedupon as short term repayment of the investment. In addition, the user isless sensitive for price changes on the energy market. This is due to thehigh effi ciency of such systems. Evaluated with LCC-analyzes, shallowgeothermal shows even higher profi ts. This is a result of low operatingcosts, low maintenance cost and a long life span.
Eftersom den solstrålning som når Jorden återstrålar till rymden så värms inte Jorden av solen - sett över en längre tid (år). Utan denna balans skulle Jorden ha blivit allt varmare med åren. Jorden är i själva verket en värmekälla i rymden till vilken den strålar ut sin nettovärme. Nettoutstrålningen sker från jordytan, skikt- för-skikt genom atmosfären, för att sedan stråla ut mot rymden vars temperatur är cirka - 270°C. Innan den globala uppvärmningen började ca 1880 var Jordens medeltemperatur 13,6°C (medelvärde av lufttemperaturen över land och hav, vilket även är jordytans medeltemperatur). Då var Jorden i termisk balans med rymden dvs nettovärmeutstrålningen var lika stor som det geotermiska värmeflödet från Jordens inre. Det geotermiska värmeflödet är den enda naturliga och ständiga nettovärmekällan på Jorden. Utstrålningen av värme från jordytan till atmosfären sker för att jordytans temperatur är högre än den i atmosfären. Atmosfärens medeltemperatur är -18,8°C vilket är precis vad som krävs för att all solinstrålning ska kunna återstråla till rymden. Jordens medeltemperatur har sedan 1880 höjts med 0,7 graderC till 14,3°C. Denna förhöjda temperatur har medfört att även utstrålningen till rymden ökat, dvs den är nu högre än enbart värmeflödet från Jordens inre. Därför måste ny nettovärme ha tillkommit under de senaste 120 åren!
Modern chaos theory is discussed and applied on turbulence.
The pressure-melting curve of ice is often found in literature dealing with ice problems. This curve originates from the excellent experimental works of G. Tammann* and P.V. Bridgman**. The method used means that ice at constant temperature is submitted to an external pressure. When increasing the pressure a sudden volume change occurs, the pressure-melting point is reached. Results from their works are summarized in this paper. An alternative experimental method was used in this study. Water is confined in a filled-up pressure tank. The water is then cooled from an initial temperature of 0°C. The ice formed creates a pressure increase in the ice-water mixture. At any temperature a corresponding pressure occurs at phase equilibrium. The temperature and the pressure are measured in the ice-water mixture. The results are in good agreement with earlier measurements. The method used, which is easy to handle even with this prototype equipment, should be more accurate than the old method since one possible source of error (the external pressure) is eliminated. The method could be used for other substances than pure water.
The pressure-melting curve of ice is often found in literature deling with ice problems. This curve originates form the eexcellent experimental works of G. Tammann (1903) and P.V. Bridgman (1912). The method used means that ice at constant temperature is submitted to an external pressure. When increasing the pressure a sudden volume change occurs, the pressure-melting point is reached. Results from their works are summarized in this paper.
An alternative experimental method was used in this study. Water is confined in a filled up pressure tank. The water is then cooled from an initial temerature of 0°C. The ice formed creates a pressure incerase in the ice-water mixture. At any temperature a corresponding pressure occurs at phase equilibrium. The temperature and the pressure are measured in the ice-water mixture. The results are in good agreement with earlier measurements. The method used, which is easy to handle even with this prototype equipment, should be more accurate than the old method since one possible source of error (the external pressure) is eliminated. The method could be used for other substances than pure water.
Renewable thermal energy is usually available with a time difference between supply and demand. This mismatch can be solved by energy storage. The most appropriate seasonal storage technologies are Underground Thermal Energy Storage (UTES) systems. The most common technologies are ATES, BTES and CTES. It is not possible, for geological or geo-hydrological reasons, to construct all these systems any place but one of them can in most cases be realised. ATES (aquifer) systems are most favourable in large-scale applications. The BTES (borehole) system is the most general system because it finds applications of all scales. CTES (rock cavern) systems are most favourable when loading and unloading powers are extremely high. This paper presents a brief summary of old and new ideas on seasonal storage of renewable thermal energy.
This summary is a personal reflection of a wonderful book on a most interesting subject. .
A seasonal heat storage system was constructed in 1982-83 at Lulea University of Technology. The heat extraction from the storage system, 2 GWh, corresponds to the heat demand of 100 one-family-houses in northern Sweden. The store has been in operation since July, 1983. The borehole heat store consists of a rock volume of 100,000 m**3, perforated by 120 vertical boreholes to a depth of 65m. The heat is stored in the rock volume itself. The boreholes work as heat exchangers. During the summer the heat store is supplied with heat via the district heating network. During the winter the heat is utilized for heating of one of the university buildings. Construction, operation and functioning of the heat store is evaluated in a research project conducted by WREL.
A solar heated thermal energy storage system for low temperature heating of 90 single-family houses in Danderyd, Sweden, was recently demonstrated in a pre-study. No heat pump was included and the peak heating demand was produced by electrical heaters. The in-the-floor heat distribution system was designed for 30oC supply temperature and the solar fraction of the system was 60%. The annual mean storage temperature varied between 30oC - 45oC in the suggested borehole heat store with a storage volume of 60000 m3 in crystalline rock. The economy of the system shows that the annual cost of this system is comparable to conventional heating systems. The annual cost (capital, energy, maintenance etc.) were investigated for 1/Solar System 2/ Small-Scale DH 3/Individual HP. The annual costs were 1070 kSEK, 1195 kSEK and 1019 kSEK respectively and the corresponding heat costs were 1000 SEK/MWh, 1100 SEK/MWh and 920 SEK/MWh. The total heat demand (1080 MWh) was really too small, from the seasonal storage point of view. In a three times larger system the suggested solar system would have been the most favourable system because of the reduced relative heat loss from the heat storage system.
Constructional work on the borehole heat store in Lulea was started in August 1982, and the store was started up in July 1983. The work was carried out on a turnkey basis by Svenska Energi System AB (SES), Lulea. The objective of the project is to demonstrate and investigate borehole heat storage technology in this experimental heat store. The actual heat store itself consists of a volume of rock amounting to about 100,000 m**3, beneath an overburden of mineral soil 2-6 m in depth. 120 boreholes have been drilled in the bedrock to a depth of 65 m, and serve as heat exchangers when charging and discharging the store. Much of the research program involves measurements intended to document performance of the store.
Review: Construction of a borehole heat store in Lulea, Sweden, began in August 1982. This seasonal heat store consists of 100 000 m s of granite. The rock volume is perforated by 120 boreholes to a depth of 65 m. The heat store has been in operation since 1983. The research work, funded by the Swedish Council for Building Research and conducted at the Lulea University of Technology, will continue until 1988. This research report describes the design and construction of the Lulea store.
Current paper summarizes ancient and modern research on dowsing. It also describes how old folk medicine have linked rheumatic pains to dowsing. Typical old cures to ease rheumatic pains were to get stung by a bee, burning nettles or jelly-fish. This was of course painful but the long-term effect was that the rheumatics pains were gone for weeks after that. This was also the starting point of current study as it was concluded that it was the piezoelectric properties of bone that explaned why those old methods seem to work. This explanation is described in detail and so is the performed laboratory test. It was concluded that the dowsing reaction is a physical reality or rather that the dowsing reactions occur under certain conditions. Performed initial tests on bone (forearm) of pig showed that a voltage of 5 V can easily be obtained by frequent knockings on top of the test bone. The paper ends with suggestions of continued research.
Over longer time-scales there is no net heat inflow to Earth since incoming solar energy is re-emitted at exactly the same rate. To maintain Earth's thermal equilibrium, however, there must be a net outflow equal to the geothermal heat flow. Performed calculations show that the net heat outflow in 1880 was equal to the geothermal heat flow, which is the only natural net heat source on Earth. Since then, heat dissipation from the global use of nonrenewable energy sources has resulted in additional net heating. In, e.g. Sweden, which is a sparsely populated country, this net heating is about three times greater than the geothermal heat flow. Such thermal pollution contributes to global warming until the global temperature has reached a level where this heat is also emitted to space. Heat dissipation from the global use of fossil fuels and nuclear power is the main source of thermal pollution. Here, it was found that one third of current thermal pollution is emitted to space and that a further global temperature increase of 1.8 °C is required until Earth is again in thermal equilibrium.
Proper design of ground heat exchangers in ground source heat pump systemsrequires a good estimate of the thermal conductivity of the ground to avoid oversizing or under-sizing of the ground heat exchanger. A good estimate of thethermal conductivity is also needed when designing a BTES (Borehole ThermalEnergy Storage) system. The ground thermal properties may be measured at aspecific location (in situ) using what is usually referred to as a thermal responsetest (TRT). In such tests, a heat injection or extraction (often at constant rate) isimposed on a test borehole. The resulting temperature response is used todetermine the ground thermal conductivity, and to test the performance ofboreholes. Since the initial mobile test rigs were built in 1995 in Sweden and theU.S.A., this technology has spread to an increasing number of countries.Within the framework of the International Energy Agency (IEA), and theImplementing Agreement on Energy Storage through Energy Conservation(ECES), the overall objectives of the international co-operation project Annex 21“Thermal Response Test” were to compile TRT experiences worldwide in order to identify problems; carry out further development; disseminate gained knowledge; promote the technology.Current report is the result of the work within the Annex 21 Subtask 1 and gives a summary of known thermal response testing activities in the world and the state-of-the-art of the technology until December 2011.
This keynote lecture summarizes the UTES state-of-the-art. It includes energy storage in aquifers (ATES), borehole thermal energy storage (BTES), rock cavern energy storage (CTES) and also large scale seasonal snow storage systems (SSS). It also includes a summary of current thermal response test (TRT) research and gives a summary of focus of the previous "Stock" conferences. The concluding remarks indicates the development trends of the different storage technologies.
Ice and snow have been used since ancient times for cooling until they were replaced by modern refrigeration in the 1950s. In recent years, however, we have seen a renewed interest in the old cooling technologies. Here, some modern large-scale snow cooling plants are described. The stored snow can be snow that is removed from city centers and roads but it is also possible to produce snow at low cost, provided that the ambient air temperature is less than −2 °C. The cooling power of snow storage is unlimited because of its constant melting temperature of 0 °C. The value of 1 ton of stored snow is €10–25 depending on the cost of electricity.
Ice and snow have been used for cooling since ancient times. Plato mentions that ice was harvested in the mountains during the winter and stored in thermally insulated buildings for cooling in the summer. Sir John Chardin reports in his “Travels in Persia 1673–1677” how ice is produced, stored, and sold for cooling of drinks in the summer