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Item type:Publication, Access status: with files , Experimental and numerical analysis of composite latent heat storage in cooling systems for power electronicsThis article presents a validated numerical model of composite latent heat storage (CLHS) used for designing cooling systems for power electronics (PE). Successfully implementing CLHS depends on many factors. Testing all of them on a test rig is expensive and time consuming. A CLHS model allows system designers to test CLHS in complex applications by varying dimensions and operating conditions. The model is written in the equation-based modelling language Modelica and represents the melting process of three-dimensional discretised CLHS. In order to validate the model a test rig is built and validation results are shown. The validated CLHS model is used in two different cooling systems. The first system is an air cooling system for power electronics with a high dynamic behaviour and lower power output. The second cooling system is a more complex liquid cooling system with a significantly increased power output. The article shows and discusses the results of both system simulations.Publicationtype: Journal ArticleScopus© Citations 2 229 191 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Experimental comparison of different composite latent heat storage devices with spatially non-constant heat loads(2016-07); An effective thermomanagement is one of the most challenging tasks in the growing field of power electronics. Within this field the cooling of electronic devices is of main interest. The cooling system should be fail-safe, low-risk, cheap, light and energy-efficient. While the heat load may vary over time, the spatial positioning of hot spots is usually constant for a given electronics component. A promising strategy for the cooling of time limited or periodic power electronic components is a composite latent heat storage (CLHS), which is a combination of a phase change material (PCM) and a thermal enhancement structure (aluminum). The thermal enhancement structure is needed, since the PCM has a very low thermal conductivity. The PCM is undergoing a phase change from solid to liquid during the cooling process while keeping a quasi-constant temperature. This leads to the question how an optimal thermal enhancement structure would look like in dependence of the spatially placement of waste heat from the power electronics. This paper presents experimental results for four composite latent heat storage devices with non-constant heat loads: The first two devices are pure aluminum and pure PCM and are used as references. The other two devices are constructed in the following way. First simulate a CLHS with pure PCM. The resulting temperature field is then averaged over time. In order to get the highest heat flux from the hot spots, fins are inserted perpendicular to isothermal contour lines. For the third device the starting points for these fins are evenly spread along the contact surface to the power electronic, for the fourth device the starting points are optimized using a genetic algorithm. The CLHS devices are cubes with boundary edge lengths of 10cm. Below the CLHS devices 5 cupper stripes are installed, that can realize independent heat loads (0-120W). The experimental time is 2400s and the temperature at the contact surface to the power electronic is monitored with 30 thermocouples.Publicationtype: Conference Paper43 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: Restricted , Experimental analysis of latent heat storages integrated into a liquid cooling system for the cooling of power electronicsThis paper presents experimental results of Thermal Energy Storages (TES) implemented into a liquid cooling system for the cooling of power electronics (PE). The experimental investigations are performed on a test rig at Hamburg University of Technology. The main objective of this study is to find a constellation, in which the weight of the liquid cooling system can be reduced by complying with a maximum temperature. For this purpose tests with a Latent Heat Storage (LHS) and a Sensible Heat Storage (SHS) were realised. The results are compared to a direct cooling of power electronics. Finally the weight reduction potential is estimated.Publicationtype: Conference Paper238 65 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Optimization of a composite latent heat storage (CLHS) with non-uniform heat fluxes using a genetic algorithmThe scope of this work is to show optimization potential for regularly structured composite latent heat storage (CLHS) devices with non-uniform heat loads by varying the distribution of fins on the contact surface to an electronic component. The modeling of the CLHS is carried out in 2D using Matlab in combination with Comsol and the effective heat capacity method for the melting process. The link between Matlab and Comsol is carried out with the Comsol–Matlab LiveLink. The modeled CLHS is a composite of aluminum with the phase change material (PCM) Parafol 22-95 (Sasol). The optimization goal was the minimization of the surface-averaged temperature at the final time tf=2400s on the contact surface. The optimization parameters were the positions of fins along this surface. Optimization results were compared to a CLHS with equally distributed fins and showed relative improvement of up to 3% for a certain aluminum/PCM-ratio. The optimization was done using the genetic algorithm (GA) of Matlab on a high performance computer (HPC) at the Hamburg University of Technology (TUHH).Publicationtype: Journal ArticleScopus© Citations 13 272 405 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Dynamic Simulation of Composite Latent Heat Storage Integrated into a Liquid Cooling SystemPublicationtype: Conference Paper50