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The aim of this study was to determine favorable operation conditions for ceiling panels containing phase change materials (PCM) for cooling applications in office rooms. A recently renovated room in the Technical University of Denmark was used to have realistic boundary conditions. Using TRNSYS 17, the performance of the PCM panels during the cooling season in passive operation, discharge by air, and discharge by water circulation were investigated. A set of simulations were performed during a representative week in the cooling period. The room was simulated with no climatic systems, PCM without active discharge, ventilation during occupied hours only, and PCM with ventilation during occupied hours. Afterwards, two discharge methods were investigated, night ventilation at different flow rates and water circulation in pipes embedded in the panels. A parametric analysis was performed to identify the influence of operation factors in the thermal environment of the room. The parameters studied were the water flow rate, supply water temperature and circulation schedule as well as the conductivity of the PCM. After selecting different operating conditions of the water discharge, simulations were performed from May to October to observe the performance of the selected operation conditions. The results show that the PCM is more effective to provide adequate indoor thermal conditions if it is discharged actively by means of water. The parameters that affect the thermal indoor environment the most are the water circulation schedule, the water supply temperature, and the PCM thermal conductivity. The water flow rate did not have a significant influence. The study shows the importance of selecting an appropriate operation and control strategy for the PCM system. The process used in the study can be potentially used as a procedure for the design of similar climatic systems to determine if active discharge of the PCM is needed and if yes, which discharge method is needed.

Fish-friendly trashracks, combining a low bar-spacing rack and bypasses, are a solution towards the fish downstream migration issue at hydroelectric intakes and rehabilitate the ecological continuity, as aimed by the European Water Framework Directive (2000). To comply to the French Environmental Code, the Hydropower plants (HPPs), located on rivers listed in list 2 according to the article L-214-17, must ensure an adequate sediment transport and free movement of fishes along the river. Each infrastructure has to be managed, and equipped according to the rules set by the administrative body in concertation with the owner or at least the operator. This study concerns inclined trashracks, which have an acute angle starting from the ground, to guide fishes to one of the surface bypass entrances. Well dimensioned bypasses should allow an efficient attraction of the fishes, while limiting the discharge in the bypasses that cause loss for hydraulic operators. In this context, a measurement campaign in a hydropower plant on the Ariège river has been carried out to characterize the velocity profiles at different positions upstream of a 26° angle trashrack with an ADCP and the flow discharge of each of the 3 bypass entrances with flowmeter measurements. The measurements show that the streamwise velocities are quite homogeneous along the rack, without significant acceleration or deceleration, and that the tangential and normal velocities, Vt and Vn, are consistent with their theoretical values. These results tend to validate the angular criteria proposed for inclined rack by Courret et Larinier [6] and studied experimentally by Raynal et al. [4] on a down-scaled model. However, it must be considered that the turbine discharge was low the day of measurement. So, these in situ measurements have to be conducted again, with a turbine discharge closed to its maximum.

A demonstrator system for a hybrid power plant is currently being built at DLR, designed for an electrical power output level of 30 kW. Since the very low energy dense exhaust gas of the fuel cell anode side represents the fuel for the combustion chamber in this application, a low calorific SOFC off-gas combustor was developed at DLR specifically for this use case. With thorough investigations on the atmospheric test rig, the expected operational range of the combustor was quantified in preceding works. Now, a novel machine design, including dilution air with an adjustable air split configuration is derived to validate the gathered information on the micro gas turbine test rig under pressurized machine conditions. This work explains the design of the combustion system and addresses the different design features specifically implemented for this use case. Since simplifications had to be made for the atmospheric combustor prototype, a significant positive influence on the operational envelope is expected with the transition to the machine configuration.

In the TripleA-reno project, a new combined labelling scheme was developed for dwellings. The combined labelling includes the evaluation of the energy performance, indoor environmental quality and well-being of occupants in dwellings. In this paper, the method of the TripleA-reno combined labelling scheme, the necessary calculations and measurements and the labelling process are introduced. In the TripleA-reno project, the developed combined labelling was successfully applied to different demonstration cases. The main results and experiences of the combined labelling for four demonstration cases located in Hungary, the Netherlands, Spain and Italy are presented.

This paper analyses the thermal states of the flat solar collector using the state variable method. The knowledge of the transient states describing the state of the solar heating installation under operating conditions enables the analysis of the heat exchange process and the development of control strategies. The analysis of variable states under operating conditions requires the development of a mathematical model describing the dynamic properties of the whole solar heating installation and the definition of the variables describing the state of the system from the energy balance perspective. The paper presents a method enabling the analysis of variables in the condition of a solar heating installation and a single solar collector based on the comparison of two models: an analogue model developed by the Equivalent Thermal Network method and a digital model, developed on the basis of performance data by the Parametric Identification method.

Two commercially available ceiling panels, one metal and one gypsum incorporating microencapsulated PCM were compared experimentally to determine their limitations and ability to provide an adequate indoor thermal environment. The experiments took place from February to May 2018 in a climate chamber at the Technical university of Denmark. In total, seven scenarios were evaluated, five with active cooling, where the flow rate and solar heat gains were varied, and two without. Results showed that according to EN 15251:2007, the RCPs maintained the best indoor thermal environment for 91% of occupancy time in Category III – operative temperature between 22oC and 27oC, and 75% in Category II – operative temperature between 23oC and 26oC, for a 140 kg/h flow rate and the reference solar heat gains. Alternatively, the PCM panels maintained Category III for only 48% of the time, while only 30% in Category II for a 220 kg/h flow rate and the reference solar heat gains. The PCM panel presented the ability to store the heat for a later time. However, the PCM panels’ solution proved inadequate in terms of heat storage capacity, pipe positioning and thermal conductivity while improvements are required in order to employ them in new and renovated buildings.

In this study the cost changes caused by the implementation of the nZEB solutions are calculated. The energy demand of a building was calculated according to the methodology for calculating the energy efficiency of buildings, using dynamic energy simulations. The financial calculations are based on the methodology described in Delegated Regulation (EU) No 244/2012 of the European Commission. The simulations and calculations for assessing the cost-effectiveness of technical solutions are based on the selected sample building. The energy efficiency solutions are derived by increasing/decreasing the insulation value of the building envelope in subsequent steps. Financial calculations were based on the investment needed to achieve the nearly zero-energy levels. The results for different combinations vary to a large degree. According to regulations new building must fulfill the low energy building (EPI class “B”) requirement without local production. The EPI value to fulfill the requirement in the cost-even range is reached in case of the GSHP and efficient DH. In case of the GSHP and efficient DH also the cost-optimal point is in the EPI class “B”. Overall the minimum ΔNPV values stay below the zero line in all the cases offering a range of opportunities to choose combinations to reach lover EPI compared to base case. The results of cost-effectiveness calculations for selected building with different combinations of structural solutions and heat sources show the possible different scenarios to reach nZEB level and the possible cost reduction.