| 1. |
- Altorkmany, Lobna, et al.
(författare)
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Effect of Working Parameters of the Plate Heat Exchanger on the Thermal Performance of the Anti-Bact Heat Exchanger System to Disinfect Legionella in Hot Water Systems
- 2018
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Ingår i: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 141, s. 435-443
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the current study is to analyze the effect of different working parameters on the thermal performance of the Anti-Bact Heat Exchanger system (ABHE). The ABHE system is inspired by nature and implemented to achieve continuous disinfection of Legionella in different human-made water systems at any desired disinfection temperature. In the ABHE system, most of the energy is recovered using an efficient plate heat exchanger (PHE). A model by Engineering Equation Solver (EES) is set-up to figure out the effect of different working parameters on the thermal performance of the ABHE system. The study shows that higher supplied water temperature can enhance the regeneration ratio (RR), but it requires a large PHE area and pumping power (PP) which consequently increase the cost of the ABHE system. However, elevate temperature in use results in a reduced PHE area and PP, which accordingly reduce the cost of the ABHE system. On the other hand, the EES-based model is used to study the effect of the length and the width of the plates used in the PHE on the RR and the required area of the PHE. Finally, taking into account the geometrical parameters, flow arrangement and the initial operating conditions of the PHE, the EES-based model is used to optimize the PHE in which its area is minimized, and the RR of the ABHE system is maximized.
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| 2. |
- Altorkmany, Lobna
(författare)
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Energy Efficient Eradication of Legionella in Hot Water Systems
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Disease related to unsafe water, poor sanitation, and lack of hygiene is some of the most common causes of illness and death all around the world. Since the first detection of Legionella in Philadelphia 1976, Legionella is recognized to cause Legionellosis which is associated with two distinct forms: Legionnaires’ disease and Pontiac fever. The fact that vaccination against Legionella disease is not efficacious enhances the effort towards developing the existence disinfection methods and inventing new technologies. Re-colonization of Legionella in hot water systems may occur within a few days or weeks after disinfection since conventional disinfection methods significantly reduce but do not eliminate pathogens. Understanding the conditions favoring Legionella occurrence in hot and cold systems will aid in developing new treatment technologies that minimize or eliminate human exposure to legionella pathogens. The work introduces the Anti-Bact Heat Exchanger (ABHE) system as a new innovative system inspired by nature. Compared to conventional disinfection methods, the ABHE system proposed to achieve continuous thermal disinfection of bacteria in hot water systems and in simultaneously saving energy and reducing the required costs. Thermodynamic analysis, experimental test and simulation validation of the ABHE by the Engineering Equation Solver (EES)-based model were achieved to define the thermal performance of the ABHE system at given operation conditions. The experimental test shows high potential of recovering heat and thus saving energy by the ABHE system. In addition, pumping power (PP) was relatively small compared to the recovered heat which implies that less energy was required compared to the recovered heat. The effect of working parameters such as temperatures and flow rate on the thermal performance of the ABHE system was furthermore investigated. The study shows that supplied water temperature has similar effects as the disinfection temperature. Namely, increasing supplied water temperature enhances the regeneration ratio (RR) but it requires a large plate heat exchanger (PHE) area and PP. On the contrary, increasing the temperature in use results in a reduced PHE area and PP. Flow rate has the greatest influence on the thermal performance of the ABHE system. Increasing flow rate leads to an increase in the required area of the PHE. The EES-based model investigated the effect of the length and the width of the plates used in the PHE on the RR and the required area of the PHE. Then, the EES-based model was used to optimize the ABHE system in which the PHE area is minimized or the RR of the ABHE system is maximized.
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| 3. |
- Altorkmany, Lobna, et al.
(författare)
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Experimental and Simulation Validation of ABHE for Disinfection of Legionella in Hot Water Systems
- 2017
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Ingår i: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 116, s. 253-265
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Tidskriftsartikel (refereegranskat)abstract
- The work refers to an innovative system inspired by nature that mimics the thermoregulation system that exists in animals. This method, which is called Anti Bacteria Heat Exchanger (ABHE), is proposed to achieve continuous thermal disinfection of bacteria in hot water systems with high energy efficiency. In particular, this study aims to demonstrate the opportunity to gain energy by means of recovering heat over a plate heat exchanger. Firstly, the thermodynamics of the ABHE is clarified to define the ABHE specification. Secondly, a first prototype of an ABHE is built with a specific configuration based on simplicity regarding design and construction. Thirdly, an experimental test is carried out. Finally, a computer model is built to simulate the ABHE system and the experimental data is used to validate the model. The experimental results indicate that the performance of the ABHE system is strongly dependent on the flow rate, while the supplied temperature has less effect. Experimental and simulation data show a large potential for saving energy of this thermal disinfection method by recovering heat. To exemplify, when supplying water at a flow rate of 5 kg/min and at a temperature of 50 °C, the heat recovery is about 1.5 kW while the required pumping power is 1 W. This means that the pressure drop is very small compared to the energy recovered and consequently high saving in total cost is promising.
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| 4. |
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| 5. |
- Altorkmany, Lobna, et al.
(författare)
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Overview of Legionella Bacteria Infection : Control and Treatment Methods
- 2009
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 6. |
- Kharseh, Mohamad, et al.
(författare)
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Analysis of the effect of global climate change on ground source heat pump systems in different climate categories
- 2015
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 78, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- Ground source heat pump (GSHP) systems exhibit high thermal performance. Consequently, they are increasingly used to heat and cool buildings. The thermal performance of GSHP systems strongly depends on the operation ground temperature and thermal quality of the building envelope (TQBE). The operation ground temperature is a function of mean annual air temperature and annual thermal load of the building. The thermal load depends on the TQBE and outside temperature. Given that ongoing global climate change (GCC) affects air temperatures, it also affects the performance of GSHP systems. The magnitude of this impact on a given GSHP system strongly depends on local weather conditions and the TQBE.The overall aim of the current study is to investigate the impact of GCC on the performance of GSHP systems in different climate. To achieve this aim, three cities located in three climate categories were considered: Stockholm, Sweden (cold), Istanbul, Turkey (mild), and Doha, Qatar (hot). In each city, two buildings were modeled. One was built according to current local building regulations, while the other was built to have a TQBE lower than the standard TQBE. Simulations were run for present (2014) and future (projected for 2050) outdoor designing conditions.
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| 7. |
- Kharseh, Mohamad, et al.
(författare)
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Combined Effect of Global Warming and Buildings Envelope on the Performance of Ground Source Heat Pump Systems
- 2014
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Ingår i: Progress in Sustainable Energy Technologies. - Berlin : Encyclopedia of Global Archaeology/Springer Verlag. - 9783319078953 - 9783319078960 ; , s. 299-315
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Bokkapitel (refereegranskat)abstract
- Heating and cooling systems as well as domestic hot water account for over 50 % of the world’s energy consumption. Due to their high thermal performance, ground source heat pump systems (GSHP) have been increasingly used to reduce energy consumption. The thermal performance of GSHP systems strongly depends on the temperature difference between indoor and ground operation temperature. This temperature difference is a function of mean annual air temperature and energy demand for heating and cooling over the year. The thermal load of a building, on the other hand is influenced by the thermal quality of the building envelope (TQBE) and outdoor temperature. Over the time, there is a change in heating and cooling load of buildings due to two reasons; improving the comfort requirements and outdoor temperature change. The overall aim of the current work is to study the impact of climatic changes in combination with TQBE on driving energy of GSHP. This was achieved by comparing the driving energy of the GSHP for different global warming (GW) scenarios and different TQBE. Under climate conditions of selected cities (Stockholm, Roma, and Riyadh), the current study shows that GW reduces the driving energy of GSHPs in cold climates. In contrast, GW increases the driving energy of GSHPs in hot climates. Also it was shown that buildings with poor TQBE are more sensitive to GW. Furthermore, the improvement of TQBE reduces the driving energy more in cold climates than in hot or mild climates.
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| 8. |
- Kharseh, Mohamad, et al.
(författare)
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Global warming’s impact on the performance of GSHP
- 2011
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:5, s. 1485-1491
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Tidskriftsartikel (refereegranskat)abstract
- Since heating and cooling systems of buildings consume 30e50% of the global energy consumption, increased efficiency of such systems means a considerable reduction in energy consumption. Ground source heat pumps (GSHP) are likely to play a central role in achieving this goal due to their high energy efficient performance. The efficiency of GSHP depends on the ground temperature, heating and cooling demands, and the distribution of heating and cooling over the year. However, all of these are affected by the ongoing climatic change. Consequently, global warming has direct effects on the GSHP performance.Within the framework of current study, heating and cooling demands of a reference building were calculated for different global warming scenarios in different climates i.e. cold, mild and hot climate. The prime energy required to drive the GSHP system is compared for each scenario and two configurations of ground heat exchangers. Current study shows that the ongoing climatic change has significant impact on GSHP systems.
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| 9. |
- Kharseh, Mohamad, et al.
(författare)
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How global warming and building envelope will change buildings energy use in central Europe
- 2012
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 97:Spec. Issue, s. 999-1004
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Tidskriftsartikel (refereegranskat)abstract
- The thermal performance of ground source heat pump systems (GSHP) strongly depends on ground temperature and energy demand for heating and cooling during the year. Certainly, increasing the global temperature means warmer ground. On the other hand, the thermal load of a building is influenced by thermal quality of building envelop (TQBE) and also influenced by the ambient air temperature. There is absolutely no doubt that the global temperature has increased during the last century. Over time, the buildings designs are changing. These result in changed thermal load of the buildings, ground temperature, and thereby changed the thermal performance of GSHPs. The objective of current work was to investigate the impact of TQBE under different global warming scenarios on driving energy and construction cost of GSHPs in Vienna. This was achieved by comparing the driving energy of the GSHP as well the required total length of the borehole heat exchanger for different GW scenarios and different TQBE. Under climate conditions of Vienna city study shows that improving the TQBE and increasing ambient air temperature result in reduced driving energy of GSHP. While is it not obvious for the required total borehole depth. Namely, after a certain degree of GW, increasing TQBE might result in increased required borehole depth.
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| 10. |
- Kharseh, Mohamad, et al.
(författare)
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How thermal quality of buildings and global warming affect ground source heat pumps system in Vienna
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The thermal performance of ground source heat pump systems (GSHP) strongly depends on ground temperature and energy demand for heating and cooling over the year. Indeed, the amount of energy lost or retained inside a building are influenced by thermal quality of building envelop (TQBE). Over time, the building design is changing to meet the increased comfort requirements. This results in changing energy demand for heating and cooling. The overall aim of current work is study the impact of climatic changes in combination with TQBE on driving energy and construction cost of GSHP. This was achieved by comparing the driving energy of the GSHP as well the required total length of the borehole heat exchanger for different GW scenarios and different TQBE. Under climate conditions of central Europe, study shows that it is not always good to built our building with high TQBE.
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