Analysis of the energy and thermal performance of a radiant cooling panel system with integrated phase change materials in very hot and humid conditions (original) (raw)
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Procedia Engineering
This study compared the effectiveness of passive and free cooling application methods of Phase change materials (PCMs) when used as energy efficient retrofitting in a residential building. A modern duplex residential building in Melbourne, Australia was considered for the case study. In passive application, PCM was installed in the ceilings of the house. In free cooling application, outdoor air was supplied to the indoor after passing it through a PCM storage unit. The study was carried out using building simulation software EnergyPlus V8.4 and computational fluid dynamics (CFD) software ANSYS V15.1. The developed simulation models of passive and free cooling applications were validated using relevant experimental data. The validated simulation models were then used to investigate the effectiveness of these PCM application methods in the selected building. The results showed that, for the studied house, free cooling application of PCM is more effective than the passive application in reducing the internal zone temperature. Under typical summer climatic conditions of Melbourne, free cooling application resulted in up to 1.8°C reduction in zone air temperature, compared to only 0.5°C when PCM was applied as passive heat storage system. The outcome of this study would be helpful in selecting the effective PCM application method for these types of residential buildings in similar climates.
Journal of Energy Storage, 2020
Free cooling of buildings uses the nocturnal outdoor air as a heat sink via a ventilation process. This could be performed by storing the night coolness for use during the daytime as appropriate. Due to the latent heat capacity, phase change material (PCM) could play an essential role in the effective operation of the free cooling systems by shifting the daytime peak load to the night. However, there is a scarceness on the technology application in hot climates. This paper presents results of a parametric investigation into the application of PCMs as thermal energy storage (TES) to provide sustainable cooling to buildings in hot arid climate by making use of the night-time free cooling. The proposed TES medium comprises an arrangement of metallic modules filled with RT28HC PCM. Numerous geometrical configurations and operational parameters have been assessed. A transient CFD simulation has been employed using ANSYS Fluent software. Validation of the numerical results with experimental data has shown a good agreement. The results have demonstrated that the temperature difference between the PCM and the air, at appropriate air flow rate would have a significant impact on the performance of the system. A free cooling system based on the proposed arrangement has the potential to meet around 42% of a typical building cooling load and has the ability to save up to 67% of building cooling energy load in summer season compared to conventional airconditioning systems in hot arid climates.
Increasing Energy Efficiency of HVAC Systems of Buildings Using Phase Change Material
ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C, 2011
Using Computational Fluid Dynamics (CFD), four different cooling systems used in modern office and residential environments are modeled in order to gain insight into the relative energy consumptions and thermal comfort levels involved. Utilizing convection and radiation technologies, full-scale models of an outward facing office room are created to compare arrangements for (a) a Variable Air Volume (VAV) all overhead air system, (b) a combined VAV and hydronic radiant system, (c) a Displacement Ventilation (DV) all-air raised floor system, and (d) a combined DV and hydronic radiant system. The room model used for each computation consists of one isothermal wall (simulating the exterior wall of
Energy Procedia, 2015
The use of PCMs for improving buildings' thermal comfort conditions and reducing summer cooling need has been largely investigated in the last decade. The capability of these materials of storing heat in latent form has been pointed out, especially when integrated in building envelopes. This paper deals with the analysis of the benefits in terms of buildings' energy saving generated by the integration of PCMs inside two types of membrane for roofing applications, i.e. a traditional bitumen membrane and an innovative cool polyurethane-based membrane. To this aim, the dynamic simulation of the energy performance of a testroom was carried out. Four configurations were simulated and compared: (i) roof covered by a bitumen sheet membrane, (ii) roof covered by a cool membrane, (iii) the cool membrane with integrated PCMs, and (iv) the bitumen membrane with integrated PCMs. Both winter and summer conditions were studied. The results showed that PCMs integrated into the cool membrane are able to guarantee a 10.4% cooling energy saving, while PCMs integrated into the bitumen membrane generate a 12.6% of energy reduction for cooling if compared to the only bitumen membrane. The same roof configurations without taking into account the roof insulation layer generate a reduction of the cooling energy requirement of about 9.4% and 16.6%, respectively. In winter conditions, the reduction of the heating demand generated by the integration of PCMs inside the bitumen membrane is about 4.4% and 6.9%, with and without considering the roof insulation, respectively. Additionally, the heating energy saving generated by including PCMs into the cool membrane is equal to 5.4% and 8.4%, with and without considering the roof insulation layer, respectively. These results demonstrated that the integration of PCMs in both cool and non-cool roof membranes is able to reduce building energy requirement in both summer and winter conditions, especially in non-insulated roof configuration.
Free cooling using phase change material for buildings in hot-arid climate
International Journal of Low-Carbon Technologies, 2018
Free Cooling based on Phase Change Materials (FCPCM) are promising sustainable technologies which aim to use the cold night ambient air as a heat sink. The stored cooling in the PCM could be used to offset the heat generated during the daytime. The current work aims to evaluate the feasibility of FCPCM technology in hot-arid regions where the cooling demand is dominant throughout most of the year. A PCM storage system comprising a number of PCM panels has been developed and assessed using Computational Fluid Dynamics modelling utilising ANSYS Fluent. The influence of operating conditions on the system performance was discussed by studying the solidification and melting process characterisation of the PCM. The results indicate that the proposed system is capable of reducing the cooling load substantially and the temperature of air supplied by the system is maintained well within the summer comfort zone of 25.5 and 30°C under the case study climate for up to 14.5 h during the discharging period. However, the system performance is less efficient during peak summer conditions, and a combination with other passive cooling strategies may be required.
The effects of carbon fuel consumption on the environment have stimulated development of a 'net-zero' energy measurement in buildings envelope for sustainable buildings a net-zero energy is key to reducing energy use and saving money .For several decades, low-income citizens in Moroccan cities have been suffering from thermal inequality, energy poverty and thermal comfort constraints.The article presents the integrated the mechanical solar ventilation and phase change materials into the building envelope using the simulation software of the thermal behavior in dynamic regime TRNSYS, this project aims at the design of a singlefamily house whose energy balance over one year of operation. In particular when the air temperature is close to the melting temperature 22 °C. A global building model consisting of a building envelope modeled and simulated in TRNSYS and EnergyPlus and the modeled exchanger Mechanic solar ventilation air/PCM fan system is simulated under climate (CASABLANCA NOUSSEUR).The energy consumption related to the specific uses of electricity is taken into account in the annual energy balance. The results show that the Mechanical solar ventilation with the phase change materials (PCM+MSV) reduces the operating temperature of the house significantly and relative humidity and maintain the demand energy from HVAC system. Indeed, the Mechanical solar ventilation has decreased its average operating temperature by about 2.7°C-3°C and created the fresh and comfort space.
E3S web of conferences, 2022
Energy consumption for cooling is the fastest-growing use of energy in buildings, and the space cooling systems have become one of the major end-users in building service systems. In recent years, phase change materials (PCM) have been increasingly adopted to reduce cooling energy consumption. This paper presents the simulations of an integrated latent heat thermal energy storage (ILHTES) system for residential buildings, which includes the PCM-to-air heat exchanger (PAHX) and air conditioner (AC). In this study, the Modelica language is adopted to develop the numerical model of the ILHTES system. A numerical heat transfer model has been used to simulate the performance of PCM-to-air heat exchanger, and it has been validated against data from the literature. Using the Modelica library AixLib, a simulation of the dynamic behavior and energy consumption of the building is performed. With the help of the ILHTES model, the optimal design of the system can be obtained using the results of the simulations throughout the cooling season. This study evaluates the energy savings potential of the ILHTES system over the conventional air conditioning system under realistic climate conditions in Budapest. The results show that an energy saving ratio of 32.4% can be achieved. The effect of PCM type on energy consumption of the ILHTES system is investigated, the results show that for three commercially available PCMs, RT25, RT20, and RT18, the ILHTES system using RT25 can utilize less energy and obtain a higher energy saving ratio.
Energy and Buildings, 2015
A novel window-based cooling unit filled with phase change materials (PCMs) is developed in an office building. At night, outdoor coolness is stored in the unit by natural ventilation and it is actively released to indoor environment during daytime. Thermal performances of this cooling unit during both cool storage and release periods are numerically investigated with a transient 3-D model. The results show that during cool storage period most parts of the PCM slabs with optimum thickness of 5 mm can
Developing New Components to Improve Energy Savings in Buildings by Using Phase Change Materials
In this paper is presented a general overview of studies which aim at developing new components to be used in buildings to improve energy savings without decreasing human thermal comfort. The main features of these studies are reminded and the paper is focused on the realisation and test of honeycomb panels filled with PCMs. Thermal response of panels is determined with a specific test bench and PCM effects are clearly shown. Modelling and numerical simulation allowed us to interpret experimental results.