Underground thermal energy storage (UTES) systems are widely used around the world, due to their relations to heating ventilating and air conditioning (HVAC) applications [1]. To achieve the required objectives of these systems, the best design of these systems should be accessed first. The process of determining the best design for any UTES system has two stages, the type selection stage and the site selection stage. In the type selection stage, the best sort of UTES system is determined. There are six kinds of UTES systems, they are: boreholes, aquifer, bit, tank, tubes in clay, and cavern [2–5]. The selection of a particular type depends on three groups of parameters. They are: Site specific, design, and operation parameters (Figure 1). Apart from site specific parameters, the other two types can be changed through the life time of the system. The site specific parameters, e.g., geological, hydrogeological, and metrological, cannot be changed during the service period of the ystem. Therefore, the design of the best type should depend, at first consideration, on site specific parameters.
Underground Thermal Energy Storage UTES systems are widely used around the world. The reason is that UTES is essential in utilizing Renewable Energy sources (RE). The efficiency of the energy system relies strongly on the efficiency of the storage system. Therefore, in the installation of a hyper-energy system, a lot of attention is to be paid in improving the storage system. In order to design an efficient storage system, firstly, standard criteria are to be investigated. These explain the process of making high efficiency storage system that must be specified. The criteria, mainly, depends on: best type and best location. These two variables are in high interference with each other. The bond between the two variables is represented by the geological, hydrological, meteorological, soil, hydrogeological properties/factors of the site. These factors are specified by geo-energy mapping. Despite the importance of this type of mapping, there is no specific criteria/formula that defines the choice. This paper aims to: give a brief literature review for UTES systems (types, classification, advantages/disadvantages for each type, and examples of an installed system). In addition, some factors within geo-energy mapping are highlighted and standard criteria to achieve good storage system are suggested. The suggested criterion comprises a process to transfer the quantity values to quality values according to the expert opinion. The suggested criteria are defined through the following stages: selecting the best type of UTES systems according to hydro-geological in site conditions; using the analytical hierarchy process to rank the best location to install the storage system and then using ArcMap (GIS-Software) to provide representative results as maps. Karbala Province (Iraq) is the study area used here
There is a global attention that the future energy systems will be based on renewable energy like solar and wind. The large-scale utilization of renewables in space heating and cooling requires large Thermal Energy Storage TES to overcome the varying supply and demand. The process of producing the best Underground Thermal Energy Storage UTES system pass through two steps: first, finding the best type of UTES system, second, finding the best locations to install UTES system. Both of these two steps depend extremely on the site specific parameters such that the depth to the groundwater, transmissivity, type of soil, the depth to the bedrock, and seepage velocity. The purpose of this paper is to explain some of the site specific parameters that the type of UTES-system depends on and explain the suitable type of UTES systems. This study considers Babylon province (Iraq) as study area. This province has electricity deficiency due to Heating Ventilating and Air Conditioning HVAC applications. The methodology of this study includes reviewing the literature that consider the study area, and using Arc Map/GIS to visualize some of the in-site parameters. The results indicate that the best type of UTES system for the considered region is either aquifer or pit type, due to the type of the soil and the depth to the crystalline bedrock. The hydraulic conductivity and the seepage velocity in the considered region are (0.0023–2.5) m/d and (1.3 × 10−6 – 3.45 × 10−3) m/d respectively. These conditions satisfy the standards which regard aquifer type.
Since the first recognized outbreak of Legionnaires' disease (LD) in 1976, it has become an increasing problem around the world especially in poor countries. Legionella (L) causes an estimated 15,000 annual cases of pneumonia in USA, and leads to death in about 20% of the cases. L is found worldwide in both natural and artificial environments e.g. spa pools, cooling towers. It infects people by inhaled contaminated aerosols that can transmit several km. The optimal temperature for L growth is 20-45C. Control of L is therefore an important health issue. Many treatment methods are used; biocides, ionisation, ozone, UV-radiation, pressure, and thermal treatment. Only thermal treatment can completely eliminate L, which is killed almost instantly at 70C. Current paper gives an overview of the Legionella problem and treatment methods.
The unbalance between supply and demand of heat can be managed by thermal energy storage (TES). For large-scale systems the underground is used as storage medium or storage volume. Aquifer storage (ATES) is most suitable for very large applications, Borehole storage (BTES) the most general system in all scales and the rock cavern storage (CTES) is best suited for extremely high loading/extraction loads. The construction of any of these systems requires knowledge about site-specific properties of the ground i.e. geology and groundwater conditions. Current paper gives a brief review of the potential and advantage of Underground Thermal Energy Storage (UTES) technology utilization in buildings for the hard climate.
The buildings thermal function is important to provide comfort to its tenants. This means to provide cooling during hot seasons and/or heating in cold season. Current study concerns modelling of a new design of thermal photo sensors that results in a more efficient heating for Tlemcen site, Algeria.
Much work has been carried out on hot water storage during the last 20-30 years, particularly on solar heat applications. Theoretical and experimental studies on the internal heat transfer have been made at laboratory scale and at larger scales. Current study, which was conducted in order to understand the stratification phenomena, involved an experimental study on the thermal behaviour in a hot water tank during charging and discharging for domestic hot water storage. Results showed no effect of stratification due to the injection fluid from the bottom of the tank and the effect of mixed convection induced by the temperature difference which created a mixture inside the tank, where the temperature was uniform across the height, and the apparition of stratification due to the fact of discharge from the bottom of the tank.
Carbon dioxide (CO2) and other greenhouse gases (GHG) are considered the main cause of many environmental issues that lead to climate change and global warming. Carbon Capture and Storage (CCS) is a promising sustainable method used for decreasing CO2 emissions. Nevertheless, for the CCS technology to be effectively put into use, some aspects should be taken into account, namely cost, capacity and durability of storage. In this paper, different CCS methods are described and the work proposes an alternative way of storing CO2 (and energy) using large-scale dry storage of biomass. The main advantage of suggested carbon storage system is that has no operation cost, and no need for maintenance and monitoring. By comparing the present project with other advanced and hi-tech projects, it is concluded that the proposed biomass storage is a cost-effective CCS technique. In the future, when the CO2 emissions are not seen as a global problem, this dry storage method enables recovery of stored wood for various purposes.
Current study concerns the fundamental problems to eliminate pathogens that are responsible for waterborne diseases. These illnesses, which have followed man throughout history, are described by occurring symptoms such as diarrhea and nausea. The various organisms identified within this document as waterborne bacterial pathogens are, e.g., Legionella (causes Pontiac fever), Salmonella (typhoid fever), and Yersinia (plague). Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper–silver ionization, ozonation, etc., but only thermal treatment can eliminate bacterial pathogens, which are killed almost instantly at 70 °C. The current chapter describes water disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day), the system can be enlarged (more hot water and more solar collector area), and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger.
The current study concerns the fundamental problems of Legionnaires disease. Four decades after Legionnaires' bacteria was first identified there is still a low level of clinical awareness. Humans are infected by inhalation of aerosolized water and/or soil contaminated with the bacteria. Several control methods are available for water disinfection: biocide, ultraviolet light sterilization, copper-silver ionization, ozonation etc. but only thermal treatment can completely eliminate Legionella, which is killed almost instantly at 70 °C. The current paper describes Legionella disinfection by a solar concentrator combined with a heat recovery system that reduces the heat demand. Though this study is made for a small system (160 l of hot water per day) the system can be enlarged (more hot water and more solar collector area) and the results are thus valid also for such larger systems. Here experiments of water treatment by a solar concentrator are summarized and analyzed where the temperature exceeds 80 °C at the outlet of the heat exchanger.
In order to utilise naturally stored heat or cold from the ground, seasonal temperature variations are required. The reason is that the ground temperature is then warmer than the air temperature during winter and colder during summer. The heating and cooling demand in North Africa varies considerably with the greatest cooling demand in the East and the greatest heating demand in the West. In parts of Algeria the mean temperature difference between the coldest and warmest month is greater than 20 °C, which is favourable. In current work it was shown that the ancient Fouggara system, even today would be interesting for heating and cooling of buildings in the Sahara desert.
This paper reports on an experimental realization and field testing of a recently proposed solar fiber optic mini dish light concentrator connected to a hot water accumulator. The prototype dish is 150 cm in diameter. In repeated test the collected and concentrated sunlight was transported in a one millimeter diameter optical fiber to a selective surface in the storage tank. This surface absorbs the radiation which remains trapped inside as it heat exchanges with tank fluid which temperature can reach 70 °C.
Underground Thermal Energy Storage (UTES) applications have slowly gained acceptance on the Swedish energy market. Two UTES concepts are successfully implemented; the ATES (aquifer storage) and the BTES (borehole storage) systems. Also snow storage in pits or caverns has reached a commercial status. The number of ATES has steadily grown to 40 large-scale plants at the end of 2002. The systems are usually designed for cold storage in district cooling application, but industrial process cooling is also common. The economical potential in terms of straight payback time is usually very favourable. However, there is still a certain risk for operational problems that might jeopardize the calculated profit. Well clogging problems and system control remain as R&D issues to be solved. From a legislation point of view any ATES application needs a permit. The process of obtaining a permit has become complex and time-consuming since a new act on environmental assessment was put into effect in 1999.BTES systems are normally used in smaller applications. At the end of 2002 there were more than 200 installations comprising more than 10 boreholes. The majority of these are applied for space cooling of commercial or institutional buildings and for process cooling within the telecommunication sector. From a technical point of view, BTES are much simpler to construct and operate than ATES. Furthermore, they can be applied in almost any kind of geology. Another advantage compared to ATES is that the permitting procedure is much simpler. The major market obstacle is that the profitability is not always acceptable if calculated as a straight payback time. To increase the market potential, there is a need for further R&D on improvement of borehole heat exchangers and of more effective drilling methods.Snow storage is still a new technology though the Sundsvall snow storage plant has been operated successfully for several years. This good example has inspired several pre-studies of new snow storage plants. These have shown that snow storage is feasible in various sizes and in different applications.
A solar heated area comprising 50 residential units is under construction. The system includes low-temperature space heating with seasonal ground storage of solar heat. Heating is supplied by 2 400 m{sup 2} of solar collectors and individual electrical heaters for supplementary heating. During the summer part of collected heat is stored in a borehole store with 100 boreholes drilled to 65 m depth. The groundwater-filled boreholes are fitted with double U-tubes. The average temperature of the seasonal store, about 60,000 m{sup 3} of crystalline rock, varies between 30 and 45 deg. C over the year. A floor heating system designed for a supply temperature of 32 deg. C provides space heating. The system is also equipped with buffer tanks for pre-heating of domestic hot water. The collectors will have favourable working conditions but the store is rather small and the estimated heat loss from the heat store is about 40% of collected solar heat. The average solar fraction is estimated to 70% and the resulting total heating cost is estimated to about 1 000 SEK/MWh ({approx}120{open_square}/MWh).
To reduce the Earth's radiation budget uncertainty related to cloud types' changes, and better understand the climate constraints resulting from long-term clouds' variability, frequent and finer (than actually existing) observations are necessary. This is one of the aims of future satellite programs such as the Global Change Observation Mission-Climate (GCOM-C) satellite, to be launched by the Japan Aerospace Exploration Agency (JAXA). To facilitate the transition from past to future observations, the actual state of climate variables (e.g., cloud types) needs to be evaluated. This evaluation is attempted in the present work with the analysis of long-term cloud types' distribution and amounts. The data set used for this study is 25 years (1982-2006) of global daytime cloud properties observed by the National Oceanic and Atmospheric Administration- Advanced Very-High-Resolution Radiometer (NOAA-AVHRR) satellites sensors. Though various calibrations have been applied on NOAA-AVHRR data, the effects of the orbit drift experienced by these satellites need to be corrected. A signal processing decomposition method allowing the filtering of the cloud types' amount trend affected by the orbit drift is used to perform the necessary corrections. The results obtained show a quantifiable improvement of the cloud amount estimation and trends of the individual NOAA satellites initial observations, at the global and regional scales. The corrected global cloud amount shows a slight decrease in its linear trend. The driving factors of this trend are the decrease in mid and low clouds overwhelming the increase in high clouds (+0.04% cloud amount/yr). A comparison with other cloud climatology studies such as the International Cloud Satellite Climatology Project (ISCCP) data set shows that the global cloud decrease noticed in NOAA-AVHRR's data is smaller. And, contrary to the NOAA-AVHRR's data, the driving force of the ISCCP linear trend is a sharp decrease in low clouds (-0.20% cloud amount/yr).
Heat storage in boreholes in rock, soil or clay is a relatively simple method for seasonal thermal energy storage. This publication gives a description of the technique of borehole heat storage in Sweden - methods, applications, experiences, and projecting aids, e.g. computer models.
This study investigates the possibility of using warm humid air for irrigation and drinking water production, by flowing air over the water surface in a solar still with saline or polluted water. Vapor will be saturated during mixing with the warm air in buried pipe. Finite difference method is employed to simulate the flow of the air long the pipe. The amount of water produced and buried pipe length depends upon the flow velocity, humid air properties and buried pipe diameter. The amount of water produced is 0.02525kg/s (0.0909m3/h). The length of the buried pipe needed in this study is 77.36m for a selected air flow velocity 5m/s with the properties of 70°C, 100% relative humidity at pipe inlet, 40°C and 100% relative humidity at pipe outlet of 0.2m pipe diameter. The results agree with a previous study (Gustafsson & Lindblom, 2001) with -4.0% deviation in water production and 7% of required pipe length
It is well established that the Coriolis Force deflects wind and water currents. However, its influence on groundwater flow is neglected. Earth’s rotation causes inertia circles in groundwater that create vortices ending up in different local pressure zones, similar to the high and low pressures in air. High pressure zones in groundwater induce, under certain conditions, a vertical flow up to the surface. This could be the missing link where hydrostatic pressure is not sufficient to explain springs in deserts, mountains and on islands in the sea. Here, simulations on the Coriolis force acting on groundwater flows are presented.
Nutrient leakage from agricultural areas in Sweden mainly occurs during the autumn in the south and during the spring in the north. The infiltration of nutrients also reaches greater depths in the south. An occurring “seasonal groundwater turnover” similar to that in lakes is the suggested mechanism. This thermal convection results from changing temperatures (densities). The 10oC groundwater in southern Sweden becomes denser as it is cooled from the surface in the autumn, while the corresponding convection in the North occurs during the spring. Performed simulations show how seasonal temperature variations, under certain conditions, initiate and drive thermal convection.
The aim was to study density-driven groundwater flow and analyse groundwater mixing because of seasonal changes in groundwater temperature. Here, density-driven convection in groundwater was studied by numerical simulations in a subarctic climate, i.e. where the water temperature was < 4 A degrees C. The effects of soil permeability and groundwater temperature (i.e. viscosity and density) were determined. The influence of impermeable obstacles in otherwise homogeneous ground was also studied. An initial disturbance in the form of a horizontal groundwater flow was necessary to start the convection. Transient solutions describe the development of convective cells in the groundwater and it took 22 days before fully developed convection patterns were formed. The thermal convection reached a maximum depth of 1.0 m in soil of low permeability (2.71 center dot 10(-9) m(2)). At groundwater temperature close to its density maximum (4 A degrees C), the physical size (in m) of the convection cells was reduced. Small stones or frost lenses in the ground slightly affect the convective flow, while larger obstacles change the size and shape of the convection cells. Performed simulations show that "seasonal groundwater turnover" occurs. This knowledge may be useful in the prevention of nutrient leakage to underlying groundwater from soils, especially in agricultural areas where no natural vertical groundwater flow is evident. An application in northern Sweden is discussed.
The issue of natural and forced groundwater movements, and its effect on the performance of ground heat exchangers is of great importance for the design and sizing of borehole thermal energy systems (BTESs). In Scandinavia groundwater filled boreholes in hard rock are commonly used. In such boreholes one or more intersecting fractures provide a path for groundwater flow between the borehole and the surrounding rock. An enhanced heat transport then occurs due to the induced convective water flow, driven by the volumetric expansion of heated water. Warm groundwater leaves through fractures in the upper part of the borehole while groundwater of ambient temperature enters the borehole through fractures at larger depths. This temperature driven flow is referred to as thermosiphon, and may cause considerable increase in the heat transport from groundwater filled boreholes. The thermosiphon effect is connected to thermal response tests, where the effective ground thermal conductivity is enhanced by this convective transport. Strong thermosiphon effects have frequently been observed in field measurements. The character of this effect is similar to that of artesian flow through boreholes.
Swedish nuclear plants are slowly being shut down as a result of a referendum in 1980. During the years after the referendum, four nuclear reactors were completed and taken into operation. The nuclear power then covered 50 % of the Swedish production capacity resulting in large over capacity, which meant inexpensive electricity. For many years thereafter direct electrical space heating was the only feasible option. This development continued until direct electrical heating was used for about 30 % of all space heating in Sweden. Swedish consumer prices were then about one third of that in most European countries. The much later deregulation of the electrical market and connection of the power grid to other European countries meant that Swedish consumer prices increased rapidly. Within a few years the prices are expected to be at the same level all over Europe and direct space heating is no longer a feasible alternative. This is why it is so attractive to Swedes to use heat pumps to reduce their electricity consumption. The present Swedish energy policy aims to a changeover from the use of prime energy sources to renewables. This is partly because of international agreements on the reduction of greenhouse emissions and partly to obtain a more independent energy system. Since the use of heat pumps mean that the electrical consumption is reduced by 70 % and also means less emission to the atmosphere, heat pump systems have been encouraged by subsidies. This present subsidy, which covers about 15 % of the investment, has been on and off during the last decades. Now, the new EU directive on energy efficient buildings offers a platform for the promotion of thermal energy
This study treats the determination of undisturbed ground temperature in a borehole for ground heating/cooling and its effect on the accuracy of a thermal response test analysis. Three different ways of estimating temperatures were used in one groundwater-fitted borehole in crystalline rock The first method, temperature logging along the borehole, is assumed to give the correct temperature profile and results in the best estimate of the mean temperature of the ground. A good estimate is also obtained by circulating a heat carrier through the borehole heat exchanger pipes while measuring the flow temperature at a short time interval (10 seconds). The calculated temperature profile is used for deriving a mean temperature of the borehole. Heat is added to the fluid by friction heat caused by the pump work, which results in an overestimation of the borehole temperature. This influencer becomes significant after 20 minutes of pumping.
During the last year thermal response tests of boreholes in rock were carried out with a mobile test equipment (TED) in several duct stores for heating and/or cooling. Most of the tests were made for the Swedish telephone company TELIA that is constructing a great number of direct cooling systems for their telephone switching stations. The size of these duct systems in the different plants tested, varies from 4 to 60 boreholes, drilled in hard rock - mostly granite and gneiss. This paper summarises results and experience from the measurements.
Es wurden 93 Patienten mit chronischen Schmerzen an der Wirbelsäule rekrutiert, um den Schmerz lindernden Effekt von „Crystal Plaster“ zu verifizieren. „Crystal Plaster“ ist ein Pflaster aus gebräuchlichen Materialien, welches auf der Hautseite zentral ein punktförmiges Kissen aus Klebstoff mit Einbettung feiner Quarzkristalle trägt.Angaben der Probanden zum Schmerzempfinden wurden als Werte auf einer elfteiligen Visual Analogue Scale (VAS) erfasst. Es wurde durchgehend zwischen Schmerz in Ruhe und bei Bewegung unterschieden, da diese nicht miteinander korrelierten. Auch die Wirkung der Pflaster auf Patienten mit Arthrose und solche mit anderen Formen der rheumatischen Erkrankung wurde getrennt analysiert.o Nach einem Tag Pflaster-Anwendung werden von den Probanden im Mittel etwa 70% der eingangs der Studie angegebenen Schmerzintensität, sowohl für den Ruhe- wie für den Bewegungsschmerz angegeben. Nach drei Monaten Anwendung liegen die VAS Werte einheitlich bei ca. 50% und nach insgesamt sechs Monaten bei Werten nahe 40% der anfänglichen Intensität.o Die Anzahl der Patienten, die eine deutliche Abnahme des Schmerzes angeben, liegt nach eintägiger Anwendung bei etwa 30%. Mit der Dauer der Anwendung nimmt dieser Anteil auf über 55% mit nur geringen Unterschieden beim Ruhe- und beim Bewegungsschmerz zu.o Nur einzelne Probanden gaben während der Pflaster Anwendung eine unerhebliche Zunahme der Schmerzen mit einer Stufe höheren VAS-Werten zu Protokoll.o Nebenwirkungen durch Anbringen und Tragen der „Crystal Plaster“ hatten wegen der Geringfügigkeit keinen Einfluss auf die mehrmonatige Anwendung.o Einen spezifischen Effekt der Kristall-tragenden Pflastern („Crystal Plaster“) im Vergleich zum Pflaster mit Glassphären im Klebstoffkissen (Pure Plaster) erkennt man bei differenzierter Betrachtung: Das „Crystal Plaster“ hat gegenüber dem Kontroll-Pflaster bei nicht-degenerativen Formen mit chronischen Schmerzen an der Wirbelsäule einen signifikant stärkeren Effekt. Zudem ist beim „Crystal Plaster“ eine einheitliche Wirkung auf den Ruhe- und Bewegungsschmerzen der jeweiligen Patienten festzustellen bei eintägiger Anwendung.Zur Langzeitanwendung des „Crystal Plaster“ wurden keine Vergleichsdaten erhoben, aber die Dauer der Wirkung über 6 Monate, noch das Ausmaß der Linderung um 60% des anfänglichen Schmerzes, sowie der deutlichen Wirkung bei 55% der Anwender können nicht als reiner Effekts eines Placebos gewertet werden.Als Erklärung für einen Teil des Schmerz lindernden Effekts des „Crystal Plaster“ wird die generelle Rolle von Pflastern als sehr starke Mediatoren von selbstheilenden Mechanismen erörtert: Dieser sog. „Placebo-Effekt“ ist bei jeder Behandlung beteiligt. Als eine physiologische Erklärung wird die „Gate Control Theory“ zur Kontrolle peripherer Schmerzen diskutiert. Zum ausgeprägten Effekt des „Crystal Plaster“ könnte auch die Gestaltung in Verbindung mit der gezielten Platzierung an den neuralgischen Stellen, die durch erfahrene Osteopathen angeleitet wird, beitragen.
The object of this study was to verify the pain reducing effect of the “Crystal Plaster”. This is a specific plaster made from dermatological proved material with a central circular spot of glue with fine quartz crystals embedded on the dermal side. A quantity of 93 patients with chronic pain at the vertebral column could be recruited for this study.
The pain sensation of the patients was registered as a value between zero and ten on the Visual Analogue Scale (VAS). In all phases of the study, the pain at rest was regarded separately from the pain felt in motion. No correlation of these different pain assessments was found.
The pronounced effect of Crystal Plaster may be enhanced by the specific plaster design in combination with its selective placement at the neuralgic sites, which is supervised by experienced osteopaths.