| 1. |
- Abdul Hamid, Akram, et al.
(författare)
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Determining the Impact of High Residential Density on Indoor Environment, Energy Use, and Moisture Loads in Swedish Apartments-and Measures for Mitigation
- 2021
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Recently, there has been an increase in apartments with a large number of inhabitants, i.e., high residential density. This is partly due to a housing shortage in general but also increased migration, particularly in suburbs of major cities. This paper specifies issues that might be caused by high residential density by investigating the technical parameters influenced in Swedish apartments that are likely to have high residential density. Interviews with 11 employees at housing companies were conducted to identify issues that might be caused by high residential density. Furthermore, simulations were conducted based on extreme conditions described in the interviews to determine the impact on the energy use, indoor environmental quality, and moisture loads. In addition, the impact of measures to mitigate the identified issues was determined. Measures such as demand-controlled ventilation, increase of a constant ventilation rate, and moisture buffering are shown to reduce the risk for thermal discomfort, mold growth, and diminished indoor air quality; while still achieving a lower energy use than in a normally occupied apartment. The results of this study can be used by authorities to formulate incentives and/or recommendations for housing owners to implement measures to ensure good indoor environmental quality for all, irrespective of residential density conditions.
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| 2. |
- Abdul Hamid, Akram, et al.
(författare)
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Impact of high residential density on the building technology, HVAC systems, and indoor environment in Swedish apartments
- 2020
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Ingår i: E3S Web of Conferences. Volyme 172, 2020.. - : EDP Sciences. ; 172
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Konferensbidrag (refereegranskat)abstract
- During the last few years, there has been an increased number of overcrowded apartments, due to increased migration but also housing shortage in general, particularly in the suburbs to major cities. The question is how the indoor environment in these apartments is affected by the high number of persons and how the problems related to high residential density can be overcome. This paper aims to specify the problem by investigating and analysing the technical parameters influenced by residential density in Swedish apartments built between 1965-1974. To map the situation, 11 interviews with employees at housing companies were conducted. Based on extreme conditions described in the interviews, simulations of the indoor climate and moisture risks at some vulnerable parts of constructions were made. Simulations were focused on moisture loads and CO2 concentrations as functions of residential density and ventilation rate. Finally, measures to combat problems associated to overcrowding are suggested. The aim is that the results should be used by authorities to formulate incentives and/or recommendations for housing companies to take actions to ensure a good indoor environment for all, irrespective of residential density conditions. © The Authors.
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| 3. |
- Abdul Hamid, Akram, et al.
(författare)
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Measuring the impact of MVHR on the energy efficiency and the IEQ in multifamily buildings
- 2019
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 195, s. 93-104
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Tidskriftsartikel (refereegranskat)abstract
- Renovating and improving the current building stock is a matter of both need and importance. In order to know if the implemented renovation measure has had an impact on the building as a system it is important to verify the impact through measurements. The aim of this project is to isolate the impact of a measure on the energy efficiency of a building as well as the indoor environmental quality. This, through detailed measurements that enable the exclusion of the impact of other factors that might affect the energy use. For this reason a mechanical ventilation system with heat recovery was installed in two apartment buildings and measurements were conducted before and after installation. Measurements were also conducted in two almost identical reference buildings, that were used as a control group for the experiment. Together with acquired data for the surrounding climate, measurements were conducted on 1)the district heat carriers to and from the buildings, 2)the temperature and relative humidity in the apartments, 3)the global horizontal radiation on site, and 4)the temperature outdoors. A survey was also conducted with the inhabitants for the assessment of the impact on the perceived indoor environmental quality. Correcting for the outdoor temperature only, a yearly reduction by 22% and 24% is achieved in the affected buildings. Changes in the global horizontal radiation clearly impact the results, however, can not be corrected for. By using the control group as a reference, further corrections can be made and the energy reduction might be determined to 15% and 34%, instead of 22% and 24% respectively.
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| 4. |
- Abdul Hamid, Akram, et al.
(författare)
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Ventilation measures for heritage office buildings in temperate climate for improvement of energy performance and IEQ
- 2020
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Ingår i: Energy and Buildings. - : Elsevier BV. - 1872-6178 .- 0378-7788. ; 211
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Tidskriftsartikel (refereegranskat)abstract
- Heritage buildings are usually culturally protected as well as naturally ventilated. As such, it is difficult to control the airflow, which depends on the temperature outdoors as well as the wind. This causes issues with the thermal comfort and the indoor air quality. In this study, status determinations were conducted for 12 heritage buildings with offices, across Sweden. Field measurements on temperature, relative humidity, CO2, and air change rates in the indoor climate, together with a survey with the occupants, confirmed these issues in these buildings. In addition, for two of the buildings, field measurements were used together with building energy performance simulations in order to determine the impact of two different ventilation measures on the indoor environmental quality (IEQ) and the energy use. A mechanical ventilation system with heat recovery, hidden inside a chimneypot, was shown to reduce CO2 concentrations and potentially reduce the energy use by up to 39 kWh∙m-2. Dampers for the reduction of the air change rates out-of-hours, installed in the pathways for the natural airflow through chimney pots, were shown to potentially reduce the energy use by up to 11 kWh∙m-2.
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| 5. |
- Abugabbara, Marwan, et al.
(författare)
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Bibliographic analysis of the recent advancements in modeling and co-simulating the fifth-generation district heating and cooling systems
- 2020
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 224
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Forskningsöversikt (refereegranskat)abstract
- District heating and cooling systems have evolved through several development stages in order to improve their energy efficiency. The latest development reached the fifth generation where customers can be producers and/or consumers of thermal energy flows towards the network. The variety and complexity of system configurations and interactions between connected customers poses a challenge in adopting a suitable modeling paradigm capable of simulating each design case. Modelica language and the Functional Mock-up Interface standard are computational tools opted by the International Energy Agency for simulating building and community energy systems. This work aims to analyze the current status in literature where these tools are utilized in building and energy simulation with focus on district heating and cooling systems. Bibliographic maps and networks are presented to analyze the literature based on different bibliometrics. Among others, the analysis shows that coupled simulation between district and building energy models is a novel research area and can benefit in reducing the oversizing of space heating and cooling systems. In addition, the analysis demonstrates that the fifth generation district heating and cooling systems require advanced control strategies. These strategies need accurate and upfront specifications to decide a proper control strategy for each design case.
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| 6. |
- Abugabbara, Marwan, et al.
(författare)
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Modelica-based simulations of decentralised substations to support decarbonisation of district heating and cooling
- 2021
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Ingår i: Energy Reports. - : Elsevier BV. - 2352-4847. ; 7:4, s. 465-472
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Tidskriftsartikel (refereegranskat)abstract
- District heating and cooling are considered effective solutions to decarbonise the energy use in the building sector. The latest generation of district heating and cooling also increases the potential of integrating heat pumps and chillers in each building substation. The benefits of such integration are the reduction of network temperature and distribution losses; the recovery of waste heat through a bidirectional network; and the decentralised production of heating and cooling. Sizing the network depends mainly on the heat flows between connected buildings. The substation performance and technical installations determine these heat flows. We present in this paper Modelica-based simulations of two design cases for substations. The first design case involves installed heat pump, chiller, and circulation pumps. Alternatively, the second design enables the heat pump to provide direct cooling through a heat exchanger. The models for these installations were developed using the Modelica language to perform continuous-time simulations. The performance in each design case was evaluated in terms of seasonal coefficient of performance and total electric energy use. An analysis on a cluster of 11 buildings suggests that the addition of the direct cooling heat exchanger can save up to 10% of the total annual electric energy use. Additional savings can be achieved by optimising the building supply temperatures and the district network temperature.
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| 7. |
- Abugabbara, Marwan, et al.
(författare)
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Validation of TEKNOsim 6 According to CIBSE TM33
- 2018
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Ingår i: Cold Climate HVAC 2018 : Sustainable Buildings in Cold Climates - Sustainable Buildings in Cold Climates. - Cham : Springer International Publishing. - 2352-2542 .- 2352-2534. - 9783030006617 - 9783030006624 ; , s. 665-676
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Bokkapitel (refereegranskat)abstract
- TEKNOsim is a simple and user-friendly program for analyzing thermal indoor climate and performing annual hourly simulations. The program was originally developed to calculate heating and cooling demands, and indoor climate conditions of a single zone building for peak winter and summer design days. However, TEKNOsim version 6 has been revised to incorporate several new features including annual energy and multi-zone simulations. These features greatly enhance the functionality and the ability of the program. Their implementation in TEKNOsim 6, however, entails a validation procedure to test the accuracy of the new algorithms. This paper presents preliminary results of the ongoing testing and validation of TEKNOsim 6 according to CIBSE TM33 tests for software accreditation and verification. The test results indicate that the new database libraries implemented in TEKNOsim 6 can be easily customized to precisely represent the actual building conditions. The results also show that the program can accurately calculate the total steady-state heat losses for all test cases of CIBSE TM33. The peak cooling loads calculated by TEKNOsim 6 are also in good agreement with CIBSE TM33 for most test cases. Some discrepancies are however observed between TEKNOsim 6 and CIBSE TM33, especially for test cases involving certain building elements. Nevertheless, TEKNOsim 6 is shown to be a fast and reliable program for performing early-design stage simulations.
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| 8. |
- Arfvidsson, Jesper, et al.
(författare)
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Tätskikt i våtrum
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 9. |
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| 10. |
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