The diminution of the fuel consumption during the flight trajectory has an impact on the cost of the travel and answers to the ecologic challenge “Green Sky”. The analysis has for objective to optimize the flight trajectory of the aircraft in order to reduce the fuel consumption. The flight trajectory is defined by a simplified description and depends on some parameters which affect the different phases of the trajectory. The flight description is introduced in a computer code and the different parameters vary in order to define their influence on the fuel consumption. The results which are obtained show the influence of the times of climb and descent and the cruise altitude on the fuel consumption. The variation according to the defined configuration is in the order of few percent. Today, all the few kilograms of fuel which are saved are important. The different phases of the flight trajectory have to be optimized to reduce the fuel consumption.

The aim of this work to study the solar chimney installed in the EPT-lab of the NTNU. The work starts with the development of a CFD model of the solar chimney and comparing with the experimental data, showing a good accuracy of the CFD results. The CFD model is used to compare three types of solar chimneys for different heights and width; obtained that the chimney installed in the EPT-lab gets higher flow rates in the most of the most of the cases. The CFD model shows a uniform temperature and velocity inside the chimney that allows developing a simple physical model of the chimney, which gives a good precision of results. Finally a simplification of the solar chimney and other systems installed in a building is simulated and also is developed another physical model for this kind of building, giving an idea of the behavior of this solar house in diverse conditions.

During the last decades the exploitation of energy from the wind has become one of the most promising renewable energy technologies. The main strive in today’s development of wind turbines is to increase the efficiency of the turbine and to build bigger rotors that are able to extract more power out of the wind.When it comes to the planning and designing of a wind park, also the aerodynamic interactions between the single turbines must be taken into account. The flow in the wake of the first row turbines is characterized by a significant deficit in wind velocity and by increased levels of turbulence. Consequently, the downstream turbines in a wind farm cannot extract as much power from the wind anymore. Furthermore, the additional turbulence in the wake could be a reason for increased material fatigue through flow-induced vibrations at the downstream rotor.The main focus of this experimental study is to investigate the local velocity deficit and the turbulence intensities in the wake behind an array of two model wind turbines. For two different turbine separation distances, the wake is scanned at several different downstream positions behind the second model turbine. Thus, it is possible to map the axial development of mean velocity and turbulence intensity and to evaluate the influence of turbine separation distance. Furthermore, the effect of varying tip speed ratios of the first and second turbine onto the wake flow field is investigated.The experiments are performed at the wind tunnel (1.9m x 2.7m cross section) at NTNU Trondheim using two model wind turbines with a rotor diameter of 0.9m. A hot wire probe is used to scan the wake behind the model turbines in defined positions.The velocity deficit and the turbulence intensity behind an array of two turbines are found to be significantly higher than behind one unobstructed turbine. Moving axially downstream, a gentle broadening of the wake can be observed. The wake profiles measured in close distances behind the rotor are characterized by evident asymmetries. Further downstream in the wake, the flow field becomes more symmetrical. The flow conditions in the inner part of the wake behind the two turbines are observed to be mainly dominated by the operational characteristics of the second turbine rotor. Although the first turbine has hardly any influence on the inner part of the wake, the outer dimensions of the wake can be tracked back to the influence of the first turbine.

In XX century, Pavement Management System has became obligatory to be used by road agencies. Need of serviceable road system demands the proper maintenance and rehabilitation plans and at that point, Pavement Performance Models step in. They are used to predict the future condition of pavement structure, basing mostly on road, climate and traffic data.The following thesis describes the attempts to implement modern Pavement Performance Models in Norway. With their help, it would be possible to predict pavement’s deterioration in better way and therefore, perform better plan maintenance and rehabilitation of the road systems.First chapter of the thesis describes the theory of Pavement Management System. It explains what Pavement Management System is and what are its levels. Later in the chapter, some of the Pavement Performance Models are described. They were considered as potentially relevant for calibration to Norwegian conditions by NordFoU- the Scandinavian co-operation program. The work of NordFoU was also described here.The historical data from Nasjonal Vegdatabank (NVDB) are described in the Chapter 3. Graphs show the rutting in all subsections on two roads- E6 and Fv 704 in Sør- Trøndelag, in Norway. E6 represents the roads with big traffic and Fv704- regional roads with small traffic. The methods of gathering road data by Statens Vegvesen are also described.In Chapter 4, the equations for calculations are shown. All equations have been adopted from the papers published by NordFoU, which are based on the HDM-4 manuals. Some of the equations come from Swedish guidelines about back- calculating E- moduli of the pavement layers. This chapter also contains assumptions and values of the coefficients that were used in calculations within following thesis. Optimisation of calibration factors was done in Excel Solver. These calculations can be found in Appendixes 7, 8, 9 and 10.The results of the calculations are shown in Chapter 5. The measured and calculated results are compared. The model of rutting has shown good correlation with reality. For E6, over 90 % of data were covered with the model. For Fv 704, the correlation was a bit worse, but still satisfactory. Value of coefficient of determination (R2) was calculated to be 58 % using the roughness model. However, in order to get better value, it is possible to further calibrate the model by modifying length of the sections and by using a new measuring equipment (ViaPPS).Chapter 6 includes the conclusion for the performed calibration and HDM-4 models. The correlation between the models and reality has been discussed. The use of studded tyres is observed to be the main contributor to deepening of the mean rut depth, other factors have negligible effect on rutting.In the following thesis calibration of only two HDM-4 models was performed. The two models were rutting and roughness respectively. A good correlation was obtained, however it is recommended to work on roughness and climate models. The rest of the models in a program can be calibrated in the future, after gathering more detailed road data, such as edge- break and cracking.

As the worldwide energy consumption continues to grow, natural gas and especially LNG are expected to keep contributing significantly with this growth. More than 95% of the installed LNG facilities use a precooling cycle as the first stage of the liquefaction process. In this work, a technical comparison between different precooling cycles for LNG processes is carried out through computational simulations using Aspen HYSYS®. The aim is to provide future project developments with a clear idea of the technical advantages/disadvantages involved in the selection of the process for the precooling cycle in LNG processes. The precooling circuit is treated as a stand-alone cycle first and then implemented in an entire liquefaction process; the propane precooled mixed refrigerant (C3MR) and the mixed fluid cascade (MFC®) processes are used for this purpose. The parameters studied are essentially coefficient of performance (β), heat exchanger UA value, compressor power, suction volumetric flow and pressure ratio. Two cases, cold (6 °C) and warm (25 °C) climate conditions are considered for each study.A three stage propane precooled process was found to be the most energetically efficient among the studied cases, even better than a two stage mixed refrigerant process (C2/C3) for both climate conditions; however, the performance in terms of energy consumption is not the only parameter taken into account and therefore a selection chart is provided. Under warm climate conditions a propane precooling circuit showed to be the most recommended process. For cold climates, however, a two stage mixed refrigerant cycle reaching ca. -50 °C is the preferred alternative, since in this case the low ambient temperature gives the propane precooled process a low share in the entire process. Other cases, such as a single stage mixed refrigerant cycle and a mixed refrigerant including n-Butane are taken into account. Based on the obtained results, a new, highly efficient configuration for natural gas liquefaction has been suggested, it is to be implemented in relatively warm climate conditions. It consists of a MFC® process with modifications in the liquefaction cycle and a propane precooling instead of the mixed refrigerant circuit; no previous reference in the open literature was found for such arrangement.

The aim of this thesis is to determine the efficiency of the hydronic heating system implemented in building with passive envelopes. Thermal losses and energy consumption of the pump are relative values for determining the efficiency.The first step towards this aim is to provide theoretical background for better understanding of the hydronic system. The advantages of this system are also presented.Good knowledge of hydronic systems, first of all, modes of transport of the work fluid and heat distribution into the space, makes a good basis for the next step- designing the system.Once the system is designed, it is possible to create mathematical model. This model together with the input values given enables creation and a running of a simulation program.In the end the results from the simulation are obtained for a typical Norwegian house which satisfies recommendation for the passive house concept.The analyses of our results shows, in spite of the heat losses from the pipes and pump energy consumption, it is feasible to fulfill the prescribed limitations regarding the Passive house energy consumption. Unfortunately, the heat losses values are not negligible and it will eventually disturb thermal comfort.The method derived in this report as well as the simulation program presented can serve as a starting point for future investigation of an assortment of hydronic systems variations. One of the logical choices is certainly a system with insulated pipes. Such system could provide the key advantage of hydronic systems compared to other heating systems. In that way they could present themselves as the best heating solution for future buildings with passive envelopes.