References of "Energy Procedia"
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See detailWater chemical evolution in Underground Pumped Storage Hydropower plants and induced consequences
Pujades, Estanislao ULiege; Orban, Philippe ULiege; Jurado Elices, Anna ULiege et al

in Energy Procedia (2017), 125

Underground Pumped Storage Hydropower (UPSH) is an alternative to manage the electricity production in flat regions. UPSH plants consist of two reservoirs of which at least one is underground. For this ... [more ▼]

Underground Pumped Storage Hydropower (UPSH) is an alternative to manage the electricity production in flat regions. UPSH plants consist of two reservoirs of which at least one is underground. For this last reservoir, abandoned mines could be considered. UPSH related activities may induce hydrochemical variations, such as the increase of the oxygen (O2) partial pressure (pO2), which may entail negative consequences in terms of environment and efficiency, especially in coal mined areas where the presence of sulfide minerals is common. This work assesses the main expected environmental impacts that UPSH using abandoned coal mines may induce. [less ▲]

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See detailPerformance correlations for characterizing the optimal off-design operation of an ORC power system
Dickes, Rémi ULiege; Dumont, Olivier ULiege; Quoilin, Sylvain ULiege et al

in Energy Procedia (2017), 129

The goal of this work is to develop a set of simple correlations in order to characterize the optimal off-design performance of an ORC power system. To this end, a 2kWe ORC test rig is investigated as ... [more ▼]

The goal of this work is to develop a set of simple correlations in order to characterize the optimal off-design performance of an ORC power system. To this end, a 2kWe ORC test rig is investigated as case study and a validated off-design model is used to assess the highest net power generation achievable by the system over its complete range of operating conditions. The off-design model employed is charge-sensitive (i.e. it imposes the total mass of refrigerant in the system) which permits to predict the ORC state (i.e. its pressures, temperatures, mass flow rates, subcooling, etc.) based on the system boundary conditions only. Since such modelling approach and optimization process are time-consuming, a set of simple analytical equations is developed so as to easily predict the optimal performance of the ORC systems. [less ▲]

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See detailEnergetic and Environmental Performances of a Domestic Hot Water Condensing Boiler Fired by Wood Pellets
Ngendakumana, Philippe ULiege; Gabriele, Fabian; Restivo, Yannick et al

in Energy Procedia (2017)

In order to assess the performances of the domestic heating boilers with a CE mark, a wood pellets fired condensing boiler has been purchased and installed in the Laboratory for tests. The objective of ... [more ▼]

In order to assess the performances of the domestic heating boilers with a CE mark, a wood pellets fired condensing boiler has been purchased and installed in the Laboratory for tests. The objective of the study was not only to check the announced performances, but mainly to investigate the influence of the different parameters affecting the functioning of the boiler, the thermal efficiency and the pollutants (NOx and CO) emission being aimed at. Tests have been performed to study the influence of the cycling frequency of the burner functioning, the overall excess air, the return water temperature, and the output power of the boiler. As announced by the manufacturer, the tested boiler fulfils the requirements of the Blue Angel Label, but the recommended value for the excess air (1.2) can be reduced to a value of about 0.4 without excessive emissions of CO. The boiler could perform better if the ON period of the cycle of the burner is increased even better if the OFF period is suppressed. The NOx are mainly formed from the nitrogen content of the pellets and their emissions can only be reduced by a lower nitrogen content of the pellets than the limit stated in the standard. Random peaks observed in the evolution of CO, the boiler being operating in steady state regime, are attributed to the combustion process of pellets which is a non-continuous process by nature. [less ▲]

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See detailExperimental investigation of four volumetric expanders
Dumont, Olivier ULiege; Dickes, Rémi ULiege; Lemort, Vincent ULiege

in Energy Procedia (2017)

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See detailGlobal optimization of the production and the distribution system for typical European HVAC systems
Randaxhe, François ULiege; Lemort, Vincent ULiege; Lebrun, Jean ULiege

in Energy Procedia (2015), 78

European countries have agreed on a new 2030 Framework with a 30% improvement in energy efficiency compared to projection and a 40% cut in greenhouse gas emissions compared to 1990 levels. With an ... [more ▼]

European countries have agreed on a new 2030 Framework with a 30% improvement in energy efficiency compared to projection and a 40% cut in greenhouse gas emissions compared to 1990 levels. With an estimated 11% of all the electrical energy used in Europe consumed by HVAC systems, the improvement of their efficiency is a key element to reach these targets. When looking at the energy flow in typical European HVAC systems, one can observe important degradation in efficiency associated to heating and cooling energy transportation systems together with a non-optimal use of the production plant. These inefficiencies are direct consequences of the system design with, quite often, a lack of consideration of the system part load or its off-design operation. This research attempts to identify the sensitivity of both cooling and heating HVAC systems to these conditions and to propose an approach to optimize the design and the operation of HVAC systems integrated in buildings considering trade-off between primary systems efficiency, distribution losses and auxiliaries consumption. [less ▲]

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See detailCalibration of building energy simulation models based on optimization: A case study
Monetti, V.; Davin, Elisabeth ULiege; Fabrizio, E. et al

in Energy Procedia (2015), 78

This study applies an optimization-based approach for calibrating building energy models using monitored data. The calibration was carried out on a test building coupling the EnergyPlus energy simulation ... [more ▼]

This study applies an optimization-based approach for calibrating building energy models using monitored data. The calibration was carried out on a test building coupling the EnergyPlus energy simulation tool with the GenOpt optimization tool. The objective function was set to minimize the difference between simulated and monitored energy consumption. For evaluating the model accuracy, the Mean Bias Error (MBE) and the Coefficient of Variation of the RMSE (Cv (RMSE)) were calculated and found consistent with ASHRAE guideline 14 limits for a model to be considered calibrated. © 2015 The Authors. [less ▲]

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See detailThermal comfort and visual comfort in an office building equipped with smart electrochromic glazing : an experimental study
Ajaji, Youness; Andre, Philippe ULiege

in Energy Procedia (2015), 78

The study aims to experimentally assess visual comfort and overheating in a highly glazed office equipped with electrochromic windows which are controlled according to an algorithm previously developed ... [more ▼]

The study aims to experimentally assess visual comfort and overheating in a highly glazed office equipped with electrochromic windows which are controlled according to an algorithm previously developed and optimized using dynamic simulation. To assess visual comfort we built two scale models of an office localized in the south of Belgium. The first one is equipped with an electrochromic window, the second one with a reference window. To assess the risk of overheating, experimental tests were performed in a climatic chamber, using an emulation of the dynamic solar gains, the internal gains and the outdoor climate in the buffer zone surrounding the climatic chamber. [less ▲]

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See detailVerification of the energy balance of a passive house by combining measurements and dynamic simulation
Rehab, Imane; Andre, Philippe ULiege; Aparecidia Silva, Cleide et al

in Energy Procedia (2015), 78

Passive houses have, at design stage, to fulfill a number of performance criteria. One of them imposes the normalized theoretical heat demand to be limited to 15 kWh/m², year. In operation, it is very ... [more ▼]

Passive houses have, at design stage, to fulfill a number of performance criteria. One of them imposes the normalized theoretical heat demand to be limited to 15 kWh/m², year. In operation, it is very difficult to check, from simple observations or measurements, the real performance of such a house: different energy vectors may be used to meet the space heating as well as the domestic hot water demand, a storage tank may be used and fed by different energy sources (heat pump, direct electricity, solar thermal). The problem is still more complicated if the house is equipped with PV panels which naturally decrease the apparent electrical consumption. In the frame of the IEA Annex 58 project, a passive house was the object of a detailed analysis aiming at estimating the different terms of the energy balance. Some terms were results of direct in situ measurements and unmeasured terms such as solar and internal gains were estimated by dynamic simulation. The combination of measurements and simulation results allowed a reconstruction of a robust energy balance. The paper provides a detailed description of the approach and of each term of the rebuilt energy balance. [less ▲]

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See detailLessons Learned from Heat Balance Analysis for Holzkirchen Twin Houses Experiment
Masy, Gabrielle; Rehab, Imane ULiege; Andre, Philippe ULiege et al

in Energy Procedia (2015)

Holzkirchen full scale dynamic experiments were conducted in the framework of IEA Annex 58 research program with the aim to obtain and apply a high quality experimental dataset for model validation of ... [more ▼]

Holzkirchen full scale dynamic experiments were conducted in the framework of IEA Annex 58 research program with the aim to obtain and apply a high quality experimental dataset for model validation of full scale buildings. A first experiment was conducted in August 2013. Two identical houses were submitted to a side by side experiment, one with blinds up, one with blinds down. That first experience lasted 42 days including an initialization period, a Randomly Ordered Logarithmic Binary Sequence of heat inputs (ROLBS), and a re-initialization followed by a free-float period. A second experiment was conducted in April 2014 in one of the two houses, with higher levels of heating power in the South oriented zones and imposed indoor temperatures in the North oriented zones. Simulations were performed with EES Engineering Equation Solver using simplified RC dynamic models. The discrepancies observed between simulated results and measured data were first explained through a deeper analysis of thermal bridges, a better assessment of solar heat gains and a better assessment of the air duct heat losses. In the second experiment, the results revealed an underestimation of the building transmission heat losses. A candidate explanation might be the air stratification which would enhance heat losses on the ceiling side. A modelization of the upper and lower room air layers was introduced. The resulting simulated indoor temperature profiles were in accordance with the measurements. A complete breakdown of heat losses and heat gains was computed for both houses, using measured temperatures as input data for the simulation. [less ▲]

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See detailSimulation of a vertical ground heat exchanger as low temperature heat source for a closed adsorption seasonal storage of solar heat
Hennaut, Samuel ULiege; Thomas, Sébastien ULiege; Davin, Elisabeth ULiege et al

in Energy Procedia (2014), 48

Get It @ ULg(opens in a new window)|View at Publisher| Export | Download | More... Energy Procedia Volume 48, 2014, Pages 370-379 2nd International Conference on Solar Heating and Cooling for Buildings ... [more ▼]

Get It @ ULg(opens in a new window)|View at Publisher| Export | Download | More... Energy Procedia Volume 48, 2014, Pages 370-379 2nd International Conference on Solar Heating and Cooling for Buildings and Industry, SHC 2013; Freiburg; Germany; 23 September 2013 through 25 September 2013; Code 104547 Simulation of a vertical ground heat exchanger as low temperature heat source for a closed adsorption seasonal storage of solar heat (Conference Paper) Hennaut, S.a , Thomas, S.a, Davin, E.a, Skrylnyk, A.b, Frère, M.b, André, P.a a University of Liège, Building Energy Monitoring and Simulation, Avenue de Longwy 185, 6700 Arlon, Belgium b University of Mons, Energy Research Cente, Boulevard Dolez 31, 7000 Mons, Belgium View references (9) Abstract This paper deals with the simulation of a vertical geothermal heat exchanger as low temperature heat source for a closed adsorption seasonal heat storage. The seasonal storage should allow reaching a nearly 100 % solar fraction for space heating of a "low energy" building". The selected adsorbent and adsorbate are respectively bromide strontium and water. The studied system, including the building and the ground exchanger, is simulated using the dynamic simulation software TRNSYS. Results show that expected performances are reached with a borehole of 100 m. The evaporation temperatures computed are really close to 0°C which might cause some problems. But an advanced research would maybe impose a deeper borehole to avoid cooling the ground on the long term. [less ▲]

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See detailDesigning large-scale CO2 capture units with assessment of solvent degradation
Léonard, Grégoire ULiege; Crosset, Cyril; Dumont, Marie-Noëlle ULiege et al

in Energy Procedia (2014), 63

Solvent degradation is one of the main operational drawbacks of post-combustion CO2 capture with amine solvents. Although the different degradation mechanisms have been largely studied in recent years, it ... [more ▼]

Solvent degradation is one of the main operational drawbacks of post-combustion CO2 capture with amine solvents. Although the different degradation mechanisms have been largely studied in recent years, it is still impossible to predict the solvent losses and the emissions of degradation products that may occur in a CO2 capture plant depending on its size and on its operating conditions. In the present work, we experimentally study the degradation of MEA monoethanolamine) under accelerated conditions implying high temperature, continuous gas feed and vigorous agitation. A special focus is set on the oxidative degradation of MEA, which is studied in the absence of CO2. Based on the experimental results, we propose a kinetic model to describe both MEA oxidative and thermal degradation pathways. The degradation kinetics is then included into a global model of the CO2 capture process, enabling solvent losses and emissions of degradation products to be predicted as a function of the process operating conditions. The predicted MEA loss is in the same order of magnitude as reported in degradation measurements from pilot plants, although lower by a factor 3. This kind of model assessing solvent degradation could and should be used for the design of large-scale CO2 capture plants in order to simultaneously consider the energy consumption of the process and its environmental impact related to the emissions of degradation products and amine solvent. Further developments shall consider the effect of SOx, NOx and dissolved metals on MEA degradation. [less ▲]

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See detailExperimental study and modeling of sorption isotherms of Kabar Sid El Cheikh Capparis spinosa L. from Bechar (South west Algeria)
Said, Bennaceur; Belkacem, Draoui; Bennamoun, Lyes ULiege et al

in Energy Procedia (2012), 18

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See detailEffects of hydrogen partial pressure on fermentative biohydrogen production by a chemotropic Clostridium bacterium in a new horizontal rotating cylinder reactor
Beckers, Laurent ULiege; Hiligsmann, Serge ULiege; MAsset, Julien et al

in Energy Procedia (2012)

In order to produce fermentative biohydrogen at high yields and production rates, efficient bioreactors have to be designed. A new reactor called anaerobic biodisc reactor allowed the production of ... [more ▼]

In order to produce fermentative biohydrogen at high yields and production rates, efficient bioreactors have to be designed. A new reactor called anaerobic biodisc reactor allowed the production of biohydrogen from glucose with the selected Clostridium sp. strain at high yields (2.49 molH2•molglucose-1) and production rates (598 mlH2•medium-1•h-1). The bacteria were fixed on a rotating support enabling efficient gas transfer from the liquid to the phase. It allowed the metabolism of the bacteria to produce more hydrogen. Moreover, an increase of the total pressure 0.18 bar lowered the yields of 19.5% while a decrease of 0.11 bar increased the yields of 7%. Our work concludes on the importance of providing good liquid to gas transfers in the biohydrogen-producing reactors. [less ▲]

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See detailExperimentation and Simulation of a Small-Scale Adsorption Cooling System in Temperate Climate
Thomas, Sébastien ULiege; Hennaut, Samuel ULiege; Maas, Stefan et al

in Energy Procedia (2012), 30

This paper focuses on the analysis of the operation of a solar cooling system based upon an adsorption chiller. The air-conditioned building studied is a laboratory located in a temperate climate region ... [more ▼]

This paper focuses on the analysis of the operation of a solar cooling system based upon an adsorption chiller. The air-conditioned building studied is a laboratory located in a temperate climate region (Belgium). The monitoring reveals thermal and electrical coefficient of performance (COP) of the cooling system for different time scale (10s to 1 month). The whole system including solar collectors, adsorption machine, recooling unit and hot storage is simulated. The models are then confronted to the measurements. Measurement period is shared between 2011 and 2012. Enhancements have been achieved during winter 2011 to have a more efficient system operation. The aim of this experimental work is to describe, for both measurement periods, the influence of operating conditions on the energy efficiency (thermal behavior and electrical consumption). On the simulation point of view, the main objective is to find accurate models for all the components. The adsorption chiller model is not yet precise enough to evaluate the performance of solar cooling in other conditions. [less ▲]

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