| 1. |
- Dipasquale, C., et al.
(författare)
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Database of energy, environmental and economic indicators of renovation packages for European residential buildings
- 2019
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Ingår i: Energy and Buildings. - : Elsevier Ltd. - 0378-7788 .- 1872-6178. ; 203
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Tidskriftsartikel (refereegranskat)abstract
- Increasing the energy efficiency with a vast impact in the residential building stock requires retrofit solutions that can be exploited with respect to a wide range of different building typologies and climates. Several tools and methodologies are nowadays available both for the assessment of building demands and for the individuation of optimum retrofit solutions. However, they are usually either too complex to be adopted by professionals or, on the contrary, oversimplified to account for the full complexity of a deep envelope and HVAC system retrofit. In this context, this paper describes a methodology developed to generate reliable information on retrofit solutions for typical buildings in different climatic conditions. Detailed numerical models are used to simulate a number of combinations of envelope and HVAC systems retrofit measures and renewable energy integration. Energy performance results are gathered in a database that allows comparing solutions, spanning over a range of more than 250,000 combinations of building types, age of construction, climates, envelope performance levels and HVAC systems configurations. Economic feasibility is also derived for each of the combinations. In this way, the accurateness of a detailed and validated calculation is made available to assist during the decision making process, with minimum computational effort being required by professionals: the variety and density of evaluated combinations allows to easily assess the performance of a specific case by interpolating among instances previously assessed. The applicability of the results to different climates and similar building typologies is verified by a comparison of the database results with a specific case dynamic simulation.
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| 2. |
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| 3. |
- Bales, BL, et al.
(författare)
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Time-resolved fluorescence quenching and electron paramagnetic resonance studies of the hydration of lithium dodecyl sulfate micelles
- 2000
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Ingår i: JOURNAL OF PHYSICAL CHEMISTRY B. - : AMER CHEMICAL SOC. - 1089-5647. ; 104:2, s. 256-263
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Tidskriftsartikel (refereegranskat)abstract
- A spin-probe method to study the surface hydration of sodium dodecyl sulfate (SDS) micelles (Bales, B. L.; Messina, L.; Vidal, A.; Peric, M.; Nascimento, O. R. J. Phys. Chem. 1998, 102, 10347; referred to as I) is applied to lithium dodecyl sulfate (LiDS)
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| 4. |
- Bales, Chris, et al.
(författare)
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Advanced Storage Concepts For Solar Houses And Low Energy Buildings - IEA-SHC Task 32
- 2005
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Ingår i: ISES Solar World Congress 2005. - Orlando, Florida, USA.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the current status of the work in Task 32 (Advance Storage Concepts for Solar and Low Energy Buildings) of the International Energy Agency’s Solar Heating and Cooling Programme (IEA-SHC). A methodology for inter-comparison has been established and boundary conditions and reference systems for this have been defined. The current status of the projects range from recently concluded feasibility studies for chemical heat storage, to prototyping, lab testing, modelling and system simulation for advanced water stores, with and without PCM content, as well as for stores based on the sorption principle. Promising new components and solutions for more classical water tanks are also described in order to define market references.
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| 5. |
- Dermentzis, G., et al.
(författare)
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A comprehensive evaluation of a monthly-based energy auditing tool through dynamic simulations, and monitoring in a renovation case study
- 2019
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 183, s. 713-726
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Tidskriftsartikel (refereegranskat)abstract
- An energy auditing tool (PHPP) was evaluated against a dynamic simulation tool (TRNSYS) and used for the assessment of energy conservation measures in a demo case study. The comprehensive comparison of useful heating and cooling demands and loads included three building types (single-, multi-family house, and office), three building energy levels (before renovation and after renovation with a heating demand of 45 and 25 kWh/(m²·a)) and seven European climates. Dynamic simulation results proved PHPP (monthly energy balance) to be able to calculate heating demand and energy savings with good precision and cooling demand with acceptable precision compared to detailed numerical models (TRNSYS). The average deviation between the tools was 8% for heating and 15% for cooling (considering climates with a relevant cooling load only). The higher the thermal envelope quality was, i.e. in case of good energy standards and in cold climates, the better was the agreement. Furthermore, it was confirmed that PHPP slightly overestimates the heating and cooling loads by intention for system design. The renovation design of a real multi-family house was executed using PHPP as energy auditing tool. Several calculation stages were performed for (a) baseline, (b) design phase, and (c) verification with monitoring in order to calculate the corresponding heating demand. The PHPP model was calibrated twice, before and after the renovation. The necessity for tool calibration, especially for the baseline, was highlighted increasing the confidence with respect to a number of boundary conditions. In this study, PHPP was tested as an energy auditing tool aiming to be a versatile and less error-prone alternative to more complex simulation tools, which require much more expert knowledge and training.
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| 6. |
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| 7. |
- Guo, Weichao, et al.
(författare)
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Mechanisms Controlling Carbon Sinks in Semi-Arid Mountain Ecosystems
- 2022
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Ingår i: Global Biogeochemical Cycles. - 0886-6236. ; 36:3
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Tidskriftsartikel (refereegranskat)abstract
- Feedbacks between the intertwined water and carbon cycles in semi-arid mountain ecosystems can introduce large uncertainties into projections of carbon storage. In this study, we sought to understand the influence of key mechanisms on carbon balances, focusing on an ecosystem whose complex terrain and large interannual variability in precipitation adds to its vulnerability to warming. We applied a dynamic vegetation-ecosystem model (Lund-Potsdam-Jena General Ecosystem Simulator) to simulate water-carbon interactions in the 104,512 km2 Mediterranean-climate ecosystems of California's Sierra Nevada for 1950–2099. Our 48 scenarios include a combination of carbon dioxide (CO2) increase, air temperature change, and varying plant rooting depths. We found that with warming (+2 and +5°C), water limitations on growth and enhanced soil respiration reduce carbon storage; however, CO2 fertilization and associated enhanced water-use efficiency offset this loss. Using the 4 km model resolution to capture steep mountain precipitation gradients, plus accounting for the several meters of actual root-accessible water storage in the region, were also important. With warming accompanied by CO2 fertilization our projections show that the Sierra Nevada sequestering at least 200 Tg (2 kg m−2) carbon, versus carbon loss with warming alone. The increase reflects coniferous forests growing at high elevations, and some increase in broadleaved forests at low-to-intermediate elevations. Importantly, uncertainty in fire disturbance could shift our finding from carbon sink to source. The improved mechanistic understanding of these feedbacks can advance modeling of carbon-water interactions in mountain-ecosystem under a warmer and potentially drier climate.
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| 8. |
- Gustafsson, Marcus, 1987-, et al.
(författare)
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Economic and environmental analysis of energy renovation packages for European office buildings
- 2017
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 148, s. 155-165
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Tidskriftsartikel (refereegranskat)abstract
- A large share of the buildings in Europe are old and in need of renovation, both in terms of functional repairs and energy efficiency. While many studies have addressed energy renovation of buildings, they rarely combine economic and environmental life cycle analyses, particularly for office buildings. The present paper investigates the economic feasibility and environmental impact of energy renovation packages for European office buildings. The renovation packages, including windows, envelope insulation, heating, cooling and ventilation systems and solar photovoltaics (PV), were evaluated in terms of life cycle cost (LCC) and life cycle assessment (LCA) through dynamic simulation for different European climates. Compared to a purely functional renovation, the studied renovation packages resulted in up to 77% lower energy costs, 19% lower total annualized costs, 79% lower climate change impact, 89% lower non-renewable energy use, 66% lower particulate matter formation and 76% lower freshwater eutrophication impact over a period of 30 years. The lowest total costs and environmental impact, in all of the studied climates, were seen for the buildings with the lowest heating demand. Solar PV panels covering part of the electricity demand could further reduce the environmental impact and, at least in southern Europe, even reduce the total costs. © 2017 Elsevier B.V.
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| 9. |
- Paul, A., et al.
(författare)
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Nuclear magnetic resonance and small-angle neutron scattering studies of anionic surfactants with macrocounterions : Tetramethylammonium dodecyl sulfate
- 2005
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 109:33, s. 15775-15779
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Tidskriftsartikel (refereegranskat)abstract
- Micellar solutions of tetramethylammonium dodecyl sulfate have been studied to determine the degree of counterion binding. Tetramethylammonium chloride was added over a wide range of surfactant concentrations such that the total concentration of tetramethylammonium ions in solution remained constant. Small angle neutron scattering experiments showed a constancy in aggregation number across this series, consistent with the constant C-aq concept of Bales et al. (J. Phys. Chent. B 2001, 105, 6798). Pulsed-field gradient and electrophoretic NMR experiments were used to determine the degree of counterion dissociation, alpha, which was found to be 0.33. This value is in contrast to the value from conductivity measurements (alpha = 0.2), but supports the concept of an aggregation number based definition of alpha.
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| 10. |
- Sotnikov, Artem, 1985, et al.
(författare)
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Simulations of a solar-assisted block-heating system
- 2017
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Ingår i: ISES Solar World Congress 2017 - IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2017, Proceedings. - Freiburg, Germany : International Solar Energy Society.
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Konferensbidrag (refereegranskat)abstract
- Two types of simulation software TRNSYS and Polysun are studied to check their suitability for solar district heating system planning. A reference case, a part of the Vallda Heberg district heating system is modelled in both tools and results are compared with available measured data and with each other. Models are successfully calibrated. TRNSYS and Polysun models have deviations in main key figures compared to the reference case less than 2% and less than 8% respectively. A sensitivity analysis of key parameters shows that the two tools give similar results.
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