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  • 1.
    Altorkmany, Lobna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Kharseh, Mohamad
    Civil Environmental Engineering Department, Chalmers University of Technology, Sweden.
    Ljung, Anna-Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Lundström, Staffan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    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 Systems2018Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 141, s. 435-443Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 2.
    Altorkmany, Lobna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Kharseh, Mohamad
    Civil Environmental Engineering Department, Chalmers University of Technology.
    Ljung, Anna-Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Lundström, Staffan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Experimental and Simulation Validation of ABHE for Disinfection of Legionella in Hot Water Systems2017Inngår i: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 116, s. 253-265Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 3. Altorkmany, Lobna
    et al.
    Nordell, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Overview of legionella bacteria infection: control and treatment methods2009Konferansepaper (Annet vitenskapelig)
  • 4.
    Kharseh, Mohamad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    How global warming and building envelope will change buildings energy use in central Europe2012Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, nr Spec. Issue, s. 999-1004Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 5.
    Kharseh, Mohamad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    How thermal quality of buildings and global warming affect ground source heat pumps system in Vienna2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    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.

  • 6.
    Kharseh, Mohamad
    et al.
    Qatar University, Mechanical & Industrial Engineering Department, Doha.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Al-Khawaj, Mohammed
    Qatar University, Mechanical & Industrial Engineering Department, Doha.
    Hassani, Ferri
    McGill University, Department of Mining Metals and Materials Engineering.
    Warming impact on energy use of HVAC system in buildings of different thermal qualities and in different climates2014Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 81, s. 106-111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to combat climate change, energy use in the building must be further reduced. Heating ventilation and air conditioning (HVAC) systems in residential buildings account for considerable fraction of global energy consumption. The potential contribution the domestic sector can make in reducing energy consumption is recognized worldwide.The driving energy of HVACs depends on the thermal quality of the building envelope (TQBE) and outside temperature. Definitely, building regulations are changing with the time toward reduce the thermal loads of buildings. However, most of the existing residential buildings were built to lower TQBE. For instant, 72% of residential dwellings in the 15-EU were built before 1972.To investigate the impact of warming on driving energy of HVACs of a residential building a computer model was developed. Three climate categories/cities were considered, i.e. Stockholm (cold), Istanbul (mild), and Doha (hot). In each city, two buildings were modeled: one was assumed to be built according to the current local buildings regulations (standard TQBE), while the anther was built to lower TQBE. The simulations were run for present and future (in 2050) outdoor designing conditions.The calculations show that the impact of the warming on annual driving energy of HVACs (reduction or increase) depends very much on the climate category and on the TQBE. Based on the climate and TQBE, the change in annual HVACs energy varies from −7.4% (in cold climate) to 12.7% (in hot climate). In mild climate, it was shown that the warming does not have significant impact on annual HVACs energy. Improving the TQBE can mitigate the impact of the warming.

  • 7.
    Kharseh, Mohamad
    et al.
    Qatar University, Mechanical & Industrial Engineering Department, Doha.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Al-Khawaja, Mohammed
    Qatar University, Mechanical & Industrial Engineering Department, Doha.
    Hassani, Ferri
    Department of Mining Metals and Materials Engineering, McGill University, H3A 2A7, Montreal.
    Analysis of the effect of global climate change on ground source heat pump systems in different climate categories2015Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 78, s. 219-225Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 8.
    Kharseh, Mohamad
    et al.
    Faculty of Engineering, Qatar University.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten. Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Al-Khawaja, Mohammed
    Faculty of Engineering, Qatar University.
    Hassani, Ferri
    Department of Mining Metals and Materials Engineering, McGill University, H3A 2A7, Montreal.
    Combined Effect of Global Warming and Buildings Envelope on the Performance of Ground Source Heat Pump Systems2014Inngår i: Progress in Sustainable Energy Technologies: Generating Renewable Energy, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2014, s. 299-315Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    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.

  • 9.
    Kharseh, Mohamad
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Altorkmany, Lobna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Nordell, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Global warming’s impact on the performance of GSHP2011Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 36, nr 5, s. 1485-1491Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 10. Kharseh, Mohamad
    et al.
    Altorkmany, Lobna
    Nordell, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    The effect of global warming on BTES systems2009Inngår i: Abstract book and proceedings : Effstock 2009: 11th International conference on Thermal Energy Storage for Energy Efficiency and Sustainability / [ed] Signhild Gehlin, Stockholm: Energi- och Miljötekniska Föreningen / EMTF Förlag , 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Global warming (GW) is linked to the use of conventional energy, mainly fossil fuels. There is a general understanding that the way to reduce GW is more efficient use of energy and increased use of renewable energy. Heating and cooling of buildings account for more than one third of the world’s primary energy consumption. Using the ground as a heat/cold source means more sustainable heating and cooling. The ongoing GW means that heat is accumulating in air, ground and water. Since BTESs are using the ground as a source of heat and cold, such systems are affected by the increasing ground temperature. Thus, heat is more easily extracted and heating demand is reduced. The warmer ground means that it is more difficult to use the ground as a cold source, while the cooling demand increases. Here, the effect of GW on the performance of BTESs was analyzed for different GW

1 - 10 of 10
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