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Pavel Charvát
Energy Institute, Brno University of Technology, Brno, Czech Republic

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Journal article
Published: 31 July 2021 in Applied Thermal Engineering
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Two metaheuristic optimisation methods were employed to solve an inverse heat transfer problem involving a phase change material (PCM). The aim was to identify the relationship ceff(T) between the effective heat capacity and temperature during melting and solidification of the PCM. Many researchers have reported a significant asymmetricity between the melting and solidification processes of PCMs. This phenomenon is usually referred to as the phase change hysteresis. To account for the phase change hysteresis, the relationship between the effective heat capacity and temperature was sought in the form of two independent ceff(T) curves; one for the melting process and the other for the solidification process. A numerical model of an air-PCM heat exchanger was employed for the development, testing, fine-tuning, and evaluation of the calculation procedure for the inverse heat transfer problem. The particle swarm optimisation method and the differential evolution method were employed for the inverse identification of the ceff(T) curves. The developed calculation procedure proved to be robust and accurate when applied to pre-simulated data where the exact solution was known to exist. When applied to the data from the experiments with the air-PCM heat exchanger, the calculation procedure confirmed its robustness (the solution was always found), but the accuracy of the results was somewhat lower. The discrepancy of between 2.9% and 15.7% was observed between the phase change enthalpies obtained by the Differential Scanning Calorimetry (DSC) and the phase change enthalpies obtained by the solution of the inverse problem. The temperatures of the phase change peaks, identified from the inverse problem, differed by between 0.34°C and 4.93°C from the temperatures obtained from the DSC analysis.

ACS Style

Martin Zálešák; Pavel Charvát; Lubomír Klimeš. Identification of the effective heat capacity–temperature relationship and the phase change hysteresis in PCMs by means of an inverse heat transfer problem solved with metaheuristic methods. Applied Thermal Engineering 2021, 197, 117392 .

AMA Style

Martin Zálešák, Pavel Charvát, Lubomír Klimeš. Identification of the effective heat capacity–temperature relationship and the phase change hysteresis in PCMs by means of an inverse heat transfer problem solved with metaheuristic methods. Applied Thermal Engineering. 2021; 197 ():117392.

Chicago/Turabian Style

Martin Zálešák; Pavel Charvát; Lubomír Klimeš. 2021. "Identification of the effective heat capacity–temperature relationship and the phase change hysteresis in PCMs by means of an inverse heat transfer problem solved with metaheuristic methods." Applied Thermal Engineering 197, no. : 117392.

Journal article
Published: 10 May 2020 in Journal of Cleaner Production
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The energy industry is currently the second largest anthropogenic source of mercury pollution worldwide, and in many countries, it is by far the largest anthropogenic source of mercury emissions. Mercury emissions can be traced to almost the entire energy industry value chain. Combustion of coal is the primary source of mercury emissions in energy production. Biomass, which is considered a renewable fuel, is also a source of atmospheric mercury emissions. A general trend from landfill waste disposal to waste incineration can be observed in many countries, but waste-to-energy incineration is also a source of mercury emissions. The increased mercury levels have been recorded in fish living in the reservoirs for hydroelectricity. The adverse effects of mercury exposure on human health have been indicated in a number of studies, and there seems to be no ‘zero effect’ exposure level. As a result, the mitigation of mercury emissions is gaining more and more attention. The overview creates the base for further research for quantification of the effect of mercury emissions on the environment and on human health, which can be expressed and quantified by Mercury Footprints.

ACS Style

Pavel Charvát; Lubomír Klimeš; Jiří Pospíšil; Jiří Jaromír Klemeš; Petar Sabev Varbanov. An overview of mercury emissions in the energy industry - A step to mercury footprint assessment. Journal of Cleaner Production 2020, 267, 122087 .

AMA Style

Pavel Charvát, Lubomír Klimeš, Jiří Pospíšil, Jiří Jaromír Klemeš, Petar Sabev Varbanov. An overview of mercury emissions in the energy industry - A step to mercury footprint assessment. Journal of Cleaner Production. 2020; 267 ():122087.

Chicago/Turabian Style

Pavel Charvát; Lubomír Klimeš; Jiří Pospíšil; Jiří Jaromír Klemeš; Petar Sabev Varbanov. 2020. "An overview of mercury emissions in the energy industry - A step to mercury footprint assessment." Journal of Cleaner Production 267, no. : 122087.

Review article
Published: 13 February 2020 in Applied Energy
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The present review provides an overview and critical analysis of recently published simulation approaches and experimental studies addressing the phase change hysteresis (PCH) and supercooling (SC) of phase change materials (PCMs). In terms of the enthalpy-temperature h(T) relationships for the solid-liquid phase changes, the PCH is a temperature delay of the h(T) curves between the melting and solidification process, while SC means that solidification does not start at the nominal solidification temperature and a lower temperature is needed for the nucleation to start. However, the PCH and SC are often neglected in the studies dealing with thermal energy storage in PCMs. Several studies indicate that experimental techniques and conditions can significantly influence the behaviour of PCMs, including the PCH and SC. Another issue is the difference in the behaviour of small samples, such as those used in the differential scanning calorimetry (DSC), and the behaviour of bulk PCM. As the DSC results are often used as inputs in simulations of systems with the bulk PCM, this issue is of high importance. Further, the entire amount of PCM does not always fully melt and solidify, and thus partial phase transitions are common in many real-life applications. Several modelling approaches have been proposed to address the PCH and SC of PCM. While simulations of complete phase change cycles are rather straightforward even with the PCH and SC involved, incomplete phase change cycles with partial phase transitions are much more challenging, and this issue has not yet been satisfactorily solved. The simulation techniques identified in the literature search were analysed, assessed, and compared to each other. The results indicate that there are only a few modelling approaches for partial phase transitions, and only some of them are reasonably validated with experimental data.

ACS Style

Lubomir Klimes; Pavel Charvat; Mahmood Mastani Joybari; Martin Zálešák; Fariborz Haghighat; Karthik Panchabikesan; Mohamed El Mankibi; Yanping Yuan. Computer modelling and experimental investigation of phase change hysteresis of PCMs: The state-of-the-art review. Applied Energy 2020, 263, 114572 .

AMA Style

Lubomir Klimes, Pavel Charvat, Mahmood Mastani Joybari, Martin Zálešák, Fariborz Haghighat, Karthik Panchabikesan, Mohamed El Mankibi, Yanping Yuan. Computer modelling and experimental investigation of phase change hysteresis of PCMs: The state-of-the-art review. Applied Energy. 2020; 263 ():114572.

Chicago/Turabian Style

Lubomir Klimes; Pavel Charvat; Mahmood Mastani Joybari; Martin Zálešák; Fariborz Haghighat; Karthik Panchabikesan; Mohamed El Mankibi; Yanping Yuan. 2020. "Computer modelling and experimental investigation of phase change hysteresis of PCMs: The state-of-the-art review." Applied Energy 263, no. : 114572.

Journal article
Published: 22 August 2019 in Energies
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The paper presents a parametric study evaluating the effects of various predictive controls on the operating parameters of heat pumps. The heat pump represents a significant power appliance in the residential sector. Its connection to the heat accumulator creates a system with considerable potential to control electricity consumption according to the needs of the electricity grid. The air-water heat pump is considered in this study. A predictive control is used for priority operation of the heat pump at periods of peak power production from renewable sources. The following were tested as the parameters of predictive control: outdoor air temperature, photovoltaic power production and wind power production. The combination of photovoltaic and wind power production was also tested. A parametric analysis considering different sizes for the thermal accumulator and the heating capacity of the heat pump were proposed. The benefits of predictive control are evaluated based on historical records of meteorological data from 2015 to 2018 in the city of Brno, Czech Republic. The data on the historical development of the real electrical energy production from renewable sources in the Czech Republic are used for regulation control in a monitored period. The main comparison parameter is the heat pump seasonal coefficient of performance (SCOP). From the carried out study results, an increase in SCOP by 14% was identified for priority operation of heat pump (HP) at periods with highest outdoor air temperature. Priority operation of HP at periods with peak photovoltaic (PV) production increased SCOP by 10.25%. A decrease in SCOP only occurred in case with priority operation of HP at peak production of wind power plants. Increasing the size of the accumulator contributes to an increase in SCOP in all assessed modifications of predictive control.

ACS Style

Jiří Pospíšil; Michal Špiláček; Pavel Charvát. Seasonal COP of an Air-to-Water Heat Pump when Using Predictive Control Preferring Power Production from Renewable Sources in the Czech Republic. Energies 2019, 12, 3236 .

AMA Style

Jiří Pospíšil, Michal Špiláček, Pavel Charvát. Seasonal COP of an Air-to-Water Heat Pump when Using Predictive Control Preferring Power Production from Renewable Sources in the Czech Republic. Energies. 2019; 12 (17):3236.

Chicago/Turabian Style

Jiří Pospíšil; Michal Špiláček; Pavel Charvát. 2019. "Seasonal COP of an Air-to-Water Heat Pump when Using Predictive Control Preferring Power Production from Renewable Sources in the Czech Republic." Energies 12, no. 17: 3236.

Journal article
Published: 15 May 2019 in Renewable Energy
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The influence of latent heat thermal energy storage integrated with the solar absorber plate was investigated through lab experiments and computer simulations. Two experimental solar air collectors were built. One collector had the solar absorber plate made of sheet metal while that of the other collector consisted of nine aluminium panels containing a paraffin-based PCM. The square-wave variation of the solar radiation intensity was considered, and a good agreement was observed between the computer simulations and experimental data. The peak-to-peak amplitudes of the outlet air temperature were reduced from 11 K (the collector with the metal sheet absorber) to 5 K (the collector with the absorber plate containing the PCM). The main contribution of the study consists in the experimental approach and in the validated model of the solar air collector for TRNSYS simulation tool. The experiments were conducted in an environmental chamber fitted with a solar simulator under both the quasi steady-state and the transient boundary conditions. In comparison to other studies with experiments conducted outdoors, the controlled environment of the climatic chamber allowed for the reduction of the uncertainty on the side of the boundary conditions, e.g. the influence of wind speed, wind direction, and cloudiness.

ACS Style

Pavel Charvát; Lubomír Klimeš; Ondřej Pech; Jiří Hejčík. Solar air collector with the solar absorber plate containing a PCM – Environmental chamber experiments and computer simulations. Renewable Energy 2019, 143, 731 -740.

AMA Style

Pavel Charvát, Lubomír Klimeš, Ondřej Pech, Jiří Hejčík. Solar air collector with the solar absorber plate containing a PCM – Environmental chamber experiments and computer simulations. Renewable Energy. 2019; 143 ():731-740.

Chicago/Turabian Style

Pavel Charvát; Lubomír Klimeš; Ondřej Pech; Jiří Hejčík. 2019. "Solar air collector with the solar absorber plate containing a PCM – Environmental chamber experiments and computer simulations." Renewable Energy 143, no. : 731-740.

Journal article
Published: 22 March 2019 in Energies
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The energy saving potential (ESP) of passive cooling of buildings with the use of an air-PCMheat exchanger (cold storage unit) was investigated through numerical simulations. One of the goals of the study was to identify the phase change temperature of a PCM that would provide the highest energy saving potential under the specific climate and operating conditions. The considered air-PCM heat exchanger contained 100 aluminum panels filled with a PCM. The PCM had a thermal storage capacity of 200 kJ/kg in the phase change temperature range of 4 ∘ C. The air-PCM heat exchanger was used to cool down the outdoor air supplied to a building during the day, and the heat accumulated in the PCM was rejected to the outdoors at night. The simulations were conducted for 16 locations in Europe with the investigated time period from 1 May–30 September. The outdoor temperature set point of 20 ∘ C was used for the utilization of stored cold. In the case of the location with the highest ESP, the scenarios with the temperature set point and without the set point (which provides maximum theoretical ESP) were compared under various air flow rates. The average utilization rate of the heat of fusion did not exceed 50% in any of the investigated scenarios.

ACS Style

Pavel Charvát; Lubomír Klimeš; Martin Zálešák. Utilization of an Air-PCM Heat Exchanger in Passive Cooling of Buildings: A Simulation Study on the Energy Saving Potential in Different European Climates. Energies 2019, 12, 1133 .

AMA Style

Pavel Charvát, Lubomír Klimeš, Martin Zálešák. Utilization of an Air-PCM Heat Exchanger in Passive Cooling of Buildings: A Simulation Study on the Energy Saving Potential in Different European Climates. Energies. 2019; 12 (6):1133.

Chicago/Turabian Style

Pavel Charvát; Lubomír Klimeš; Martin Zálešák. 2019. "Utilization of an Air-PCM Heat Exchanger in Passive Cooling of Buildings: A Simulation Study on the Energy Saving Potential in Different European Climates." Energies 12, no. 6: 1133.

Articles
Published: 29 November 2018 in Journal of Building Performance Simulation
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The paper deals with the comparison of the one-dimensional (1D) and three-dimensional (3D) models of a thermally activated wall panel with a microencapsulated phase change material. The 3D model was created in the off-the-shelf simulation tool COMSOL Multiphysics. The 1D model was an in-house developed TRNSYS type. The main advantage of the 1D model is the short computation time but it comes at the expense of lower accuracy and less detailed results. In most building performance simulations, however, detailed knowledge of the temperature distribution over the surface of a wall is not important. For this reason, the results of both models were compared in terms of the mean surface temperature of the wall panels, the outlet water temperature, and the overall heating and cooling capacity of the panels. The two models provided very similar results for the practical range of water flow rates. The mass flow rate of water had a relatively small influence on the mean surface temperature and the heating and cooling capacity of the panels. For the one-tube mass flow rates of water between 0.25 and 2 g/s, the mean surface temperature was in the range of 28–29.5C in the heating scenario and 21–21.5C in the cooling scenario, with the heating and cooling capacity ranges of 65 W/m2 to 75 W/m2 and 35 W/m2 to 40 W/m2, respectively.

ACS Style

L. Klimeš; P. Charvát; M. Ostrý. Thermally activated wall panels with microencapsulated PCM: comparison of 1D and 3D models. Journal of Building Performance Simulation 2018, 12, 404 -419.

AMA Style

L. Klimeš, P. Charvát, M. Ostrý. Thermally activated wall panels with microencapsulated PCM: comparison of 1D and 3D models. Journal of Building Performance Simulation. 2018; 12 (4):404-419.

Chicago/Turabian Style

L. Klimeš; P. Charvát; M. Ostrý. 2018. "Thermally activated wall panels with microencapsulated PCM: comparison of 1D and 3D models." Journal of Building Performance Simulation 12, no. 4: 404-419.

Journal article
Published: 12 April 2018 in Energies
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A study into the performance of a solar chimney and a solar photovoltaic (PV)-powered fan for ventilation applications was carried out using numerical simulations. The performance of the solar chimney was compared with that of a direct current (DC) fan powered by a solar PV panel. The comparison was carried out using the same area of the irradiated surface—the area of the solar absorber plate in the case of the solar chimney and the area of the solar panel in the case of the photovoltaic-powered fan. The two studied cases were compared under various solar radiation intensities of incident solar radiation. The results indicate that the PV-powered fans significantly outperform solar chimneys in terms of converting solar energy into the kinetic energy of air motion. Moreover, ventilation with PV-powered fans offers more flexibility in the arrangement of the ventilation system and also better control of the air flow rates in the case of battery storage.

ACS Style

Lubomír Klimeš; Pavel Charvát; Jiří Hejčík. Comparison of the Energy Conversion Efficiency of a Solar Chimney and a Solar PV-Powered Fan for Ventilation Applications. Energies 2018, 11, 912 .

AMA Style

Lubomír Klimeš, Pavel Charvát, Jiří Hejčík. Comparison of the Energy Conversion Efficiency of a Solar Chimney and a Solar PV-Powered Fan for Ventilation Applications. Energies. 2018; 11 (4):912.

Chicago/Turabian Style

Lubomír Klimeš; Pavel Charvát; Jiří Hejčík. 2018. "Comparison of the Energy Conversion Efficiency of a Solar Chimney and a Solar PV-Powered Fan for Ventilation Applications." Energies 11, no. 4: 912.

Conference paper
Published: 12 May 2017 in EPJ Web of Conferences
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EPJ Web of Conferences, open-access proceedings in physics and astronomy

ACS Style

Pavel Charvat; Josef Stetina; Tomáš Mauder; Lubomir Klimes. Visual monitoring of the melting front propagation in a paraffin-based PCM. EPJ Web of Conferences 2017, 143, 02042 .

AMA Style

Pavel Charvat, Josef Stetina, Tomáš Mauder, Lubomir Klimes. Visual monitoring of the melting front propagation in a paraffin-based PCM. EPJ Web of Conferences. 2017; 143 ():02042.

Chicago/Turabian Style

Pavel Charvat; Josef Stetina; Tomáš Mauder; Lubomir Klimes. 2017. "Visual monitoring of the melting front propagation in a paraffin-based PCM." EPJ Web of Conferences 143, no. : 02042.

Journal article
Published: 11 April 2017 in Journal of Heat Transfer
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The fast and accurate modeling of phase change is of a significant importance in many processes from steel casting to latent heat thermal energy storage. The paper presents a numerical case study on the transient 3D heat diffusion problem with phase change. Three different approaches to modeling of the solid–liquid phase change in combination with four commonly used numerical schemes are compared for their efficiency, accuracy, applicability, simplicity of implementation, and robustness. The possibility of parallel decomposition of the approaches is also discussed. The results indicate that the best accuracy was achieved with the second-order implicit methods, and the best efficiency was reached with the simple explicit methods.

ACS Style

Tomas Mauder; Pavel Charvat; Josef Stetina; Lubomir Klimes. Assessment of Basic Approaches to Numerical Modeling of Phase Change Problems—Accuracy, Efficiency, and Parallel Decomposition. Journal of Heat Transfer 2017, 139, 084502 .

AMA Style

Tomas Mauder, Pavel Charvat, Josef Stetina, Lubomir Klimes. Assessment of Basic Approaches to Numerical Modeling of Phase Change Problems—Accuracy, Efficiency, and Parallel Decomposition. Journal of Heat Transfer. 2017; 139 (8):084502.

Chicago/Turabian Style

Tomas Mauder; Pavel Charvat; Josef Stetina; Lubomir Klimes. 2017. "Assessment of Basic Approaches to Numerical Modeling of Phase Change Problems—Accuracy, Efficiency, and Parallel Decomposition." Journal of Heat Transfer 139, no. 8: 084502.

Journal article
Published: 15 October 2016 in Journal of Theoretical and Applied Mechanics
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The paper presents a theoretical parametric study into latent heat thermal energy storage (LHTES) employing polymeric hollow fibres embedded in a phase change material (PCM). The polymeric hollow fibres of five inner diameters between 0.5mm and 1.5mm are considered in the study. The effectiveness-NTU method is employed to calculate the thermal performance of a theoretical LHTES unit of the shell-and-tube design. The results indicate that the hollow fibres embedded in a PCM can mitigate the drawback of low thermal conductivity of phase change materials. For the same packing fraction, the total heat transfer rates between the heat transfer fluid and the PCM increase with the decreasing diameter of the hollow fibres. This increase in the heat transfer rate and thus the efficiency of the heat exchange to some extent compensate for the energy consumption of the pump that also increases with the decreasing fibre diameter.

ACS Style

Jiří Hejčík; Pavel Charvát; Lubomír Klimeš; Ilya Astrouski. A PCM-water heat exchanger with polymeric hollow fibres for latent heat thermal energy storage: a parametric study of discharging stage. Journal of Theoretical and Applied Mechanics 2016, 54, 1285 .

AMA Style

Jiří Hejčík, Pavel Charvát, Lubomír Klimeš, Ilya Astrouski. A PCM-water heat exchanger with polymeric hollow fibres for latent heat thermal energy storage: a parametric study of discharging stage. Journal of Theoretical and Applied Mechanics. 2016; 54 (4):1285.

Chicago/Turabian Style

Jiří Hejčík; Pavel Charvát; Lubomír Klimeš; Ilya Astrouski. 2016. "A PCM-water heat exchanger with polymeric hollow fibres for latent heat thermal energy storage: a parametric study of discharging stage." Journal of Theoretical and Applied Mechanics 54, no. 4: 1285.

Conference paper
Published: 01 September 2016 in Journal of Physics: Conference Series
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Materials undergoing a phase change have a number of applications in practice and engineering. Computer simulation tools are often used for investigation of such heat transfer problems with phase changes since they are fast and relatively not expensive. However, a crucial issue is the accuracy of these simulation tools. Numerical methods from the interface capturing category are frequently applied. Such approaches, however, allow for only approximate tracking of the interface between the phases. The paper presents an accuracy analysis and comparison of two widely used interface capturing methods—the enthalpy and the effective heat capacity methods—with the front tracking algorithm. A paraffin-based phase change material is assumed in the study. Computational results show that the front tracking algorithm provides a significantly higher accuracy level than the considered interface capturing methods.

ACS Style

Lubomír Klimeš; Tomáš Mauder; Pavel Charvát; Josef Štétina. An accuracy analysis of the front tracking method and interface capturing methods for the solution of heat transfer problems with phase changes. Journal of Physics: Conference Series 2016, 745, 032136 .

AMA Style

Lubomír Klimeš, Tomáš Mauder, Pavel Charvát, Josef Štétina. An accuracy analysis of the front tracking method and interface capturing methods for the solution of heat transfer problems with phase changes. Journal of Physics: Conference Series. 2016; 745 (3):032136.

Chicago/Turabian Style

Lubomír Klimeš; Tomáš Mauder; Pavel Charvát; Josef Štétina. 2016. "An accuracy analysis of the front tracking method and interface capturing methods for the solution of heat transfer problems with phase changes." Journal of Physics: Conference Series 745, no. 3: 032136.

Proceedings article
Published: 13 November 2015 in Volume 3: Biomedical and Biotechnology Engineering
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Phase change materials are nowadays used in a wide range of technical applications such as energy storage, building temperature comfort, food-freezing, etc. The accurate modelling of this process is important for the performance and usability of many technologies. Analytical solutions can be used only for simple heat transfer problems which make the numerical methods the only possible way how to deal with complex multidimensional cases. This paper deals with the comparison of commonly used numerical schemes for heat diffusion with phase change and its parallel computation possibilities.

ACS Style

Tomas Mauder; Lubomir Klimes; Pavel Charvat; Josef Štétina. Various Approaches to Numerical Discretization of Thermal Model With Phase Change. Volume 3: Biomedical and Biotechnology Engineering 2015, 1 .

AMA Style

Tomas Mauder, Lubomir Klimes, Pavel Charvat, Josef Štétina. Various Approaches to Numerical Discretization of Thermal Model With Phase Change. Volume 3: Biomedical and Biotechnology Engineering. 2015; ():1.

Chicago/Turabian Style

Tomas Mauder; Lubomir Klimes; Pavel Charvat; Josef Štétina. 2015. "Various Approaches to Numerical Discretization of Thermal Model With Phase Change." Volume 3: Biomedical and Biotechnology Engineering , no. : 1.

Conference paper
Published: 13 November 2015 in Volume 3: Biomedical and Biotechnology Engineering
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Simulations of building performance or HVAC systems performance usually cover a time period of several weeks, months or even a year. Therefore, the computational demand of simulation models of buildings or HVAC systems can be quite constraining for their practical application. A substantial simplification of the simulated problem is usually necessary to reduce the computational demand. The paper reports the development of a quasi 1D model of a thermally activated layer with phase change material. The model was developed in MATLAB and subsequently implemented as a TRNSYS type. The model was validated with data obtained from experiments with thermally activated panels. The experimental panels contained a 15 mm thick layer of gypsum plaster comprising 30 wt.% of microencapsulated phase change material. Plastic tubes for liquid heat carrier (water in the presented study) were embedded at the bottom of the plaster layer. Thermal imaging was used to acquire the average surface temperatures of the panels in the experimental investigations. The experimental and numerical results were in a good agreement.

ACS Style

Pavel Charvat; Lubomir Klimes; Milan Ostry; Josef Štétina. A Validated TRNSYS Model of Thermally Activated Layer With Phase Change Material. Volume 3: Biomedical and Biotechnology Engineering 2015, 1 .

AMA Style

Pavel Charvat, Lubomir Klimes, Milan Ostry, Josef Štétina. A Validated TRNSYS Model of Thermally Activated Layer With Phase Change Material. Volume 3: Biomedical and Biotechnology Engineering. 2015; ():1.

Chicago/Turabian Style

Pavel Charvat; Lubomir Klimes; Milan Ostry; Josef Štétina. 2015. "A Validated TRNSYS Model of Thermally Activated Layer With Phase Change Material." Volume 3: Biomedical and Biotechnology Engineering , no. : 1.

Review
Published: 01 November 2015 in Energy and Buildings
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ACS Style

Yeliz Konuklu; Milan Ostry; Halime O. Paksoy; Pavel Charvat. Review on using microencapsulated phase change materials (PCM) in building applications. Energy and Buildings 2015, 106, 134 -155.

AMA Style

Yeliz Konuklu, Milan Ostry, Halime O. Paksoy, Pavel Charvat. Review on using microencapsulated phase change materials (PCM) in building applications. Energy and Buildings. 2015; 106 ():134-155.

Chicago/Turabian Style

Yeliz Konuklu; Milan Ostry; Halime O. Paksoy; Pavel Charvat. 2015. "Review on using microencapsulated phase change materials (PCM) in building applications." Energy and Buildings 106, no. : 134-155.

Conference paper
Published: 25 March 2014 in EPJ Web of Conferences
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EPJ Web of Conferences, open-access proceedings in physics and related sciences

ACS Style

Pavel Charvat; Josef Stetina; Ondrej Pech; Lubomir Klimes; Milan Ostry. Experimental investigation of stabilization of flowing water temperature with a water-PCM heat exchanger. EPJ Web of Conferences 2014, 67, 02046 .

AMA Style

Pavel Charvat, Josef Stetina, Ondrej Pech, Lubomir Klimes, Milan Ostry. Experimental investigation of stabilization of flowing water temperature with a water-PCM heat exchanger. EPJ Web of Conferences. 2014; 67 ():02046.

Chicago/Turabian Style

Pavel Charvat; Josef Stetina; Ondrej Pech; Lubomir Klimes; Milan Ostry. 2014. "Experimental investigation of stabilization of flowing water temperature with a water-PCM heat exchanger." EPJ Web of Conferences 67, no. : 02046.

Journal article
Published: 01 January 2014 in Energy and Buildings
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ACS Style

Pavel Charvat; Lubomír Klimeš; Milan Ostrý. Numerical and experimental investigation of a PCM-based thermal storage unit for solar air systems. Energy and Buildings 2014, 68, 488 -497.

AMA Style

Pavel Charvat, Lubomír Klimeš, Milan Ostrý. Numerical and experimental investigation of a PCM-based thermal storage unit for solar air systems. Energy and Buildings. 2014; 68 ():488-497.

Chicago/Turabian Style

Pavel Charvat; Lubomír Klimeš; Milan Ostrý. 2014. "Numerical and experimental investigation of a PCM-based thermal storage unit for solar air systems." Energy and Buildings 68, no. : 488-497.

Journal article
Published: 10 May 2013 in Procedia Engineering
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The costs of fuels and energy in the Czech Republic have rapidly increased in the last two decades. This situation in the energy market has bolstered the interest in the development of heating and cooling systems utilizing renewable energy sources, especially solar energy. The utilization of renewable energy sources in residential and office buildings very often requires an effective way of thermal energy storage. Thermal energy storage is an essential part of most of the solar heating and cooling systems. The solar gains through the transparent part of the building envelope can reduce energy consumption for heating during the heating season thus saving the energy from conventional heat sources (electricity, natural gas, coal). On the other hand, solar heat gains through the building envelope contribute to overheating in summer or during the sunny days in spring and autumn. From this point of view the energy storage capacity of building structures plays an important role in indoor temperature control in a building. That means that building structures can be employed to store solar heat during the sunny and warm part of the day and release it at night when the outdoor temperature decreases. This approach is applicable only on sunny days with relatively high outdoor temperatures during the day and low outdoor temperatures at night. The sensible heat storage capacity of common building structures depends on the weight of the structure, its thermal capacity and the temperature difference between the start and the end of the heat storage process. Because of the thermal comfort requirements that limit the indoor temperature swing during the day the thermal capacity of common building materials is usually insufficient to provide thermal storage for this purpose. This is where latent heat thermal storage can be applied. Latent heat storage represents much more effective way to improve the thermal storage capacity of a building structure.

ACS Style

Milan Ostry; Pavel Charvat. Materials for Advanced Heat Storage in Buildings. Procedia Engineering 2013, 57, 837 -843.

AMA Style

Milan Ostry, Pavel Charvat. Materials for Advanced Heat Storage in Buildings. Procedia Engineering. 2013; 57 ():837-843.

Chicago/Turabian Style

Milan Ostry; Pavel Charvat. 2013. "Materials for Advanced Heat Storage in Buildings." Procedia Engineering 57, no. : 837-843.

Conference paper
Published: 09 April 2013 in EPJ Web of Conferences
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The paper deals with experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solarabsorber. The main purpose of heat storage in solar thermal systems is to store heat when the supply of solar heat exceeds demand and release it when otherwise. A number of heat storage materials can be used for this purpose; the phase change materials among them. Short-term latent heat thermal storage integrated with the solar absorber can stabilize the air temperature at the outlet of the collector on cloudy days when solar radiation intensity incident on a solar collector fluctuates significantly. Two experimental front-and-back pass solar air collectors of the same dimensions have been built for the experimental investigations. One collector had a “conventional” solar absorber made of a metal sheet while the solar absorber of the other collector consisted of containers filled with organic phase change material. The experimental collectors were positioned side by side during the investigations to ensure the same operating conditions (incident solar radiation, outdoor temperature).

ACS Style

Pavel Charvat; O. Pech; J. Hejcik. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber. EPJ Web of Conferences 2013, 45, 1127 .

AMA Style

Pavel Charvat, O. Pech, J. Hejcik. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber. EPJ Web of Conferences. 2013; 45 ():1127.

Chicago/Turabian Style

Pavel Charvat; O. Pech; J. Hejcik. 2013. "Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber." EPJ Web of Conferences 45, no. : 1127.

Journal article
Published: 01 January 2013 in Advanced Materials Research
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The paper deals with the mathematical model of the multi-layer wall containing the phase change material (PCM). The model utilizes the effective heat capacity method for modeling the latent heat of phase change and the control volume method is used for the discretization of the model. The utilization of the model is then demonstrated on the problem of the optimal design of the multi-layer wall with the PCM. The TMY2 data for the city of Brno were used in simulations as operational conditions. The main attention is aimed at the determination of the optimal thickness of the PCM layer for the multi-layer wall design with various thicknesses of the masonry.

ACS Style

Lubomir Klimes; Pavel Charvat; Josef Stetina. Mathematical Model of Multi-Layer Wall with Phase Change Material and its Use in Optimal Design. Advanced Materials Research 2013, 649, 295 -298.

AMA Style

Lubomir Klimes, Pavel Charvat, Josef Stetina. Mathematical Model of Multi-Layer Wall with Phase Change Material and its Use in Optimal Design. Advanced Materials Research. 2013; 649 ():295-298.

Chicago/Turabian Style

Lubomir Klimes; Pavel Charvat; Josef Stetina. 2013. "Mathematical Model of Multi-Layer Wall with Phase Change Material and its Use in Optimal Design." Advanced Materials Research 649, no. : 295-298.