In opening, this diploma thesis is introducing the company Daikin Device Czech s.r.o. In the next step the principle of function of a heat pump. Then there are described its main parts. First part of this thesis is dedicated to assembly line of the heat pump’s switchboxes. The layout of the assembly line is described and added with description of used health and quality measures. Main part is speaking about running test of the switchbox line. The main function of the test is described alongside with description of the process of making the testing software.

This master thesis deals with ignition systems which are used in cars vehicles with gas engines and also with setting of the best moment of ignition of gasoline-air mixture in cylinders of engine. Ways of gas injection at diesel engines and their control systems are also described in this thesis. Next chapter deals with control unit and describes main actions which are necessary for today’s motor vehicles. As illustration is used example of succession of actions which are necessary for calculation and setting regular value of pre-ignition. At the end is shown animation, which can be used for practice lessons in a subject Automobile Electric and Electronic Systems as a example. It will simplify understanding of described activities which are all accomplished by central control unit. For purposes of laboratory lessons is in this thesis also discussed measuring of engine performance with changes of parameter of central control unit.

This master’s thesis deals with theme of turbocharger seals. The aims of a thesis are to compare a turbocharger seals used in PBS Turbo turbochargers and to describe a testing of a seals. Principle of turbocharging and types of turbocharger are described in fist part. Next point of the thesis is describing of a face seals and non-contacting seals. The main part of the thesis describes kinds and reasons of seals testing; also contains comparison between labyrinth seals and piston ring, comparison of seals of PBS Turbo’s turbochargers and assesses the impact of turbocharger angle on the tightness of the seal.

The aim of this Diploma thesis is a description of gas heat pump (GHP) technology and the possibility of their usage in real life. Also units from the major manufactures of GHP units in the Czech Republic and abroad are evaluated from technical and economical point of view. The thesis as well includes a part where is decided if it is better to further develop GHP units with higher or lower performance. In the last part of thesis are cooling circuits designed for both lower and higher performance, than performance of existing GHP unit Polo 100. As a result, the units with higher performance are more perspective. Therefore heat plate exchangers, which serve as a condenser and an evaporator, are designed for unit with higher performance.

Diploma thesis deals with direct cooling systems in food processing plants. The work focuses on the description of the components of the refrigerant cycle, with emphasis on the choice of refrigerant. The result is a design of direct cooling system in the food factory in the variants with refrigerant R404A and R717. The work describes the advantages and disadvantages of various options. The work includes an experimental section which deals with the measure-ment and processing of the actual values of the refrigerant cycle and the comparison of two cold sources.

V súčasnosti sa kladie veľký dôraz na znižovanie produkcie emisií, čistotu a kvalitu životného prostredia. Tieto trendy sa týkajú všetkých odvetví, tak isto aj stavebného priemyslu a vykurovania budov. Doposiaľ bolo najrozšírenejším typom vykurovania spaľovanie fosílnych palív. Do popredia sa však dostávajú tepelné čerpadlá a začínajú zaberať výrazný podiel trhu. Kvôli dopytu po tepelných čerpadlách vzrastá počet výrobcov a konkurencia. Cieľom výrobcov je zvyšovanie účinnosti tepelných čerpadiel a zároveň znižovanie výrobných nákladov na dosiahnutie lepšej pozície na trhu. Predložená práca sa zaoberá procesmi prebiehajúcimi v chladivovom okruhu tepelného čerpadla. Skúma správanie chladiva počas kondenzácie a možnosti zvýšenia účinnosti tepelného čerpadla. Zvýšenie účinnosti je dosiahnuté podchladením chladiva počas kondenzácie na zvýšenie tepelných ziskov. To je dosiahnuté zaradením druhého elektronického expanzného ventilu za kondenzátorom. Táto technológia je však finančne náročná. Práca sa zaoberá výpočtom kapiláry na základe praktických meraní, ktorá bude zadržiavať chladivo v kondenzátore a bude plniť podobnú úlohu ako expanzný ventil. Následne sú porovnané výsledky jednotlivých meraní. Výsledky sú porovnané voči jednoduchému systému, kde nedochádza k podchladeniu chladiva. V závere práce je analýza výsledkov jednotlivých systémov.

This thesis describes the design of cooling ice rink. Cooling system design is based on a physical nature, measured data and observations from practice. The result is a proposal cooling system with the highest possible cooling factor, which uses waste heat for technology needs snow pit and hot water, in order to achieve the lowest cost of operation ice rink.

The compressor for air supply to the fuel cell stack is a critical component of the balance of plant, especially for mobile applications. The main requirements of the compressor are the performance regarding pressure ratio, mass flow and efficiency at minimal size and weight. The turbo compressor technology is ideally suited to cope with these requirements. The lifetime requirement and the necessity of oil and particle free air supply advised to employ air bearings. The fuel cell air supply requirements are in conflict with the turbo compressor pressure ratio and mass flow characteristics. Possible solutions and their impact onto compressor design and fuel cell operation are described in this paper. The chosen system design approach considering all design aspects and its interactions during the design phase is beneficial in order to achieve the most lightweight and efficient air supply system for fuel cells. Experimental validation of an air bearing turbo compressor for a 100 kW fuel cell stack on an aerodynamic test rig verifies the predicted performance.

Design space exploration (DSE) is a tool used to evaluate and compare designs as part of the design selection process. While evaluating every possible design in a design space is infeasible, understanding design behavior and response throughout the design space may be accomplished by evaluating a subset of designs and interpolating between them using surrogate models. Surrogate modeling is a technique that uses low-cost calculations to approximate the outcome of more computationally expensive calculations or analyses, such as finite element analysis (FEA). While surrogates make quick predictions, accuracy is not guaranteed and must be considered. This research addressed the need to improve the accuracy of surrogate predictions in order to improve DSE of structural responses. This was accomplished by performing comparative analyses of linear and nonlinear dimensionality-reduction-based radial basis function (RBF) surrogate models for emulating various FEA nodal results. A total of four dimensionality reduction methods were investigated, namely principal component analysis (PCA), kernel principal component analysis (KPCA), isometric feature mapping (ISOMAP), and locally linear embedding (LLE). These methods were used in conjunction with surrogate modeling to predict nodal stresses and coordinates of a compressor blade. The research showed that using an ISOMAP-based dual-RBF surrogate model for predicting nodal stresses decreased the estimated mean error of the surrogate by 35.7% compared to PCA. Using nonlinear dimensionality-reduction-based surrogates did not reduce surrogate error for predicting nodal coordinates. A new metric, the manifold distance ratio (MDR), was introduced to measure the nonlinearity of the data manifolds. When applied to the stress and coordinate data, the stress space was found to be more nonlinear than the coordinate space for this application. The upfront training cost of the nonlinear dimensionality-reduction-based surrogates was larger than that of their linear counterparts but small enough to remain feasible. After training, all the dual-RBF surrogates were capable of making real-time predictions. This same process was repeated for a separate application involving the nodal displacements of mode shapes obtained from a FEA modal analysis. The modal assurance criterion (MAC) calculation was used to compare the predicted mode shapes, as well as their corresponding true mode shapes obtained from FEA, to a set of reference modes. The research showed that two nonlinear techniques, namely LLE and KPCA, resulted in lower surrogate error in the more complex design spaces. Using a RBF kernel, KPCA achieved the largest average reduction in error of 13.57%. The results also showed that surrogate error was greatly affected by mode shape reversal. Four different approaches of identifying reversed mode shapes were explored, all of which resulted in varying amounts of surrogate error. Together, the methods explored in this research were shown to decrease surrogate error when performing DSE of a turbomachine compressor blade. As surrogate accuracy increases, so does the ability to correctly make engineering decisions and judgements throughout the design process. Ultimately, this will help engineers design better turbomachines.

<p>The purpose of this research was to determine what components of a complex centrifugal  compression system inlet needed to be modelled to accurately predict the swirl and total pressure  distortions at the compressor face. Two computational models were developed. A full-fidelity case  where all the inlet geometry was modelled and a reduced model where a small portion of the inlet  was considered. Both the numerical cases were compared with experimental data from a research  compressor rig developed by Honeywell Aerospace. The test apparatus was designed with a  modular inlet system to develop swirl distortion patterns. The modular inlet system utilized  transposable baffles within the radial-to-axial section of the inlet and blockage plates of varying  sizes and geometries at the inlet to this section.  Discerning the dominant inlet component that dictates distortion behavior at the compressor  face would allow the reduced modelling of inlet components for compression systems and would  allow coupling with more tortuous systems. Furthermore, it would reduce the design iteration and  simulation time of the inlet systems. Several investigations utilizing a reduced model only  considering a radial-to-axial inlet are available in literature, but no comprehensive justification has  been presented as to the impact this has on the distortion behavior.   Experimental surveys of flow conditions just upstream of the inducer of the centrifugal  compressor were conducted at several operating conditions. The highest and lowest mass flow  rates of these operating points were simulated using ANSYS CFX 2020R1 for both the  computational models. Multiple inlet configurations were simulated to test the robustness of the  reduced model in comparison to the full fidelity. The numerical simulations highlighted  shortcomings of the instrumentation used to characterize the experimental flow field at the inducer,  particularly with respect to total pressure distortion. Furthermore, transient pressure data were  measured in experiment and indicated unsteady fluctuations in the inlet that would not be captured  by steady computational fluid dynamic simulations. These data matched locations of disagreement  with swirl distortion behavior at high mass flow rates. This suggested that transient vortex  movement occured at the aerodynamic interface plane in certain configurations.   The total pressure distortion metrics between the two models were remarkably comparable.  Furthermore, the simplified model accurately predicted the mixing losses associated with the  blockage plates at the inlet to the radial-to-axial inlet using a simple inlet extension. Swirl  18  distortion was dictated by the radial-to-axial inlet. The reduced model data trends were comparable  with experiment for both the baffle and blocker plate configurations. The swirl intensities for all  configurations were comparable between the two models. The reduced model swirl directivity  trends matched those of experiment. The most notable deviations between the full-fidelity model  and the reduced model were observed with swirl directivity numerics. </p>