Effect of solar ventilation on thermal improvement and energy efficiency of buildings using phase change materials (original) (raw)
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This article aims to provide an overview of best practices for the design and construction of more energy efficient building envelopes. So 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. They resist indoor temperatures of less than 16°C and more than 32°C, which causes the phenomenon of thermal stress. Among the sources of energy consumption, Heating, Ventilation and Air Conditioning (HVAC) systems represent about 50% of the total expenditure in buildings this considerable proportion can be explained in part by the great temperature variations recorded in Morocco, which make it essential to provide air conditioning or heating almost at all times. The development of green buildings thus inevitably requires an optimization of the use of HVAC SYSTEMS. 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 single-family house whose energy
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. They resist indoor temperatures of less than 16°C and more than 32°C, , many software come to us from the world to simulate the building envelope. we are working only with software related to: calculation and simulationof electrical and thermal zones, which causes the phenomenon of thermal stress. Among the sources of energy consumption, Heating, Ventilation and air Conditioning (HVAC) systems represent about 50% of the total expenditure in buildings this considerable proportion can be explained in part by the great temperature variations recorded in Morocco, which make it essential to provide air conditioning or heating almost at all times. The development of green buildings thus inevitably requires an optimization of the use of powered mechanical ventilation can increase the airflow and improve heat transfer. Similarly, solar mechanical ventilation can be used to accelerate the heat flow and also using the local building materials p.c.m , with low environmental impact. In this perspective, a clear difference between the use of HVAC systems during the day and at night has been observed. This is because, during the day, the solar irradiation incident on the façade of a building coupled with the various internal gains (occupancy density, lighting, etc.) cause a high demand for air conditioning. This article presents a comparison between the Trnsys and energy plus. If the diversity of these programs is a boon in that it allows many different simulations to be compared, it also poses a problem in terms of comparison of results and even choice of program.
When it comes to building simulation, many applications and programs come to us from all over the world. A multitude of software has been developed for similar purposes by different universities and laboratories. In this section we are concerned only with programs related to: calculation of thermal and electrical load zones, building envelope, solar gains, solar ventilation, renewable energy production, building electrical equipment, HVAC systems and equipment, and economic performance evaluation. These programs also take into account for the most part climatic input data. The use of simulation is decisive in the design process of a new building. It allows the evaluation of different alternatives in terms of energy performance and occupant comfort and is thus an essential decision-making tool. The resulting increase in the precision requirements of the calculations makes it essential to appreciate the uncertainties associated with these forecasts in order to improve the construction and evaluation process. This article presents a comparison between the evaluations of uncertainties based on the results of simulations in the design phase. If the diversity of these programs is a boon in that it allows many different simulations to be compared, it also poses a problem in terms of comparison of results and even choice of program. A major current challenge is therefore to succeed in making these different software programs communicate, many research works have been published in this sense.
Journal of Cleaner Production, 2022
Incorporating phase change material (PCM) into buildings in hot climates is an excellent strategy for better thermal comfort and energy-saving in future smart cities. Nevertheless, PCM elements suffer from adverse temperature behaviour at night due to the dissipation of stored diurnal heat. Night ventilation has been proposed as a promising solution and clean strategy for decreasing indoor building temperature at night and increasing PCM benefits in the following cycle. In this study, the effect of the natural night ventilation (NNV) period on the thermal performance of a room-integrated PCM is investigated experimentally under hot summer conditions in Iraq. Six NNV periods (with 1 h increment) are studied for six consecutive days in terms of average indoor and operative temperature reduction. Moreover, the work is extended to study the average heat gain difference in each day cycle to show the contribution of PCM to energy-saving. The results showed a slight enhancement in the average indoor air temperature of the PCM room compared with another identical no-PCM room regardless of the NNV period due to high outdoor ambient temperature at night. However, NNV for 4 h can reduce the average indoor air temperature by 28.6% compared with 1 h of NNV, whereas a slight extra reduction was achieved for 5 and 6 h. Besides, NNV slightly affected the operative temperature at night against no impact during the day, which was more influenced by the solar radiation and high diurnal ambient temperature. The results further revealed that a total average heat gain difference of 63.1-87.9 W was achieved, in which the roof contributed by more than 44% in each cycle.
Improving the energy performance of the building envelope using phase change materials
The building envelope (walls, floor, windows,roof) is a very important element of the design as it can have a effect on the energy performance of the building, that is comfortable all year round can be achieved with reasonable levels of insulation, reduced thermal bridging, summertime shading features, and ventilation. Depending on the properties of the thermal zone where we are, it is therefore possible to integrate PCM and optimize their parameters in order to favorably diphase the energy consumption peaks and energy consumption and, by the same token, significantly reducing the use of the HC system. Consequently, the integration of this PCM in the envelopes of new buildings or in renovation would contribute to reduce the energy bill in the building sector in Morocco. So the (PCM) represents a sustainable alternative to reduce energy consumption for this a thermal dynamic simulation was realized with TRNSYS 204. Since PCM involves large latent heat at small temperature phase changes, PCM is used for temperature stabilization and for storing heat with large energy densities and capacity the storage in combination with rather small temperature changes. The simulation was carried out for the climate zone of Morocco (Casablanca Nouasseur). The results of the simulation showed that the use of phase change materials in brick walls reduced overheating in the summer period, decreasing the ambient temperature of the indoor air by 3 ° C.
Thermal efficiency analysis of buildings with phase change materials
Sustainability, Agri, Food and Environmental Research, 2021
Increasing global temperature is alarming the need for construction industry to have thermally efficient building materials. Incorporating Phase Change Materials (PCM) in buildings is widely accepted method for reduction in temperature, thereby achieving better thermal efficiency. This paper focuses on the assessment of thermal performance of PCM-incorporated building under tropical climatic condition. The simulation process was carried out using Design Builder Software and the developed building model is validated with the results available in the literature. A parametric study is also performed in order to identify the effect of different parameters like building orientation, window to wall ratio, ceiling height and construction material on the indoor air temperature. The results showed that the maximum reduction was up to 2.76°C.
2021
Global warming presents major challenges to the world and especially to hot climatic countries, as global warming-driven increases in outdoor temperatures consequently increase the demand for cooling energy in buildings. A country like Egypt, whose climate is classified as hot and arid, is facing major challenges to meet the required high demand for energy that is mainly consumed for space cooling purposes in buildings, which will worsen due to global warming. The residential sector in Egypt consumes almost 50% of the energy produced compared to other sectors, and the high demand of air-conditioning systems in the Egyptian residential sector contributes the most to this consumption of energy. Residential buildings in Egypt are built with minimal energy efficiency standards which makes vital the need for space cooling. Thus, the idea of enhancing the thermal behaviour of residential buildings in Egypt is essential to reduce the heavy burden on the energy sector due to cooling needs. ...
Passive Study of Energy Efficiency of a Building with PCM on the Roof during Summer in Casablanca
Journal of Power and Energy Engineering, 2016
Energy efficiency in buildings is today a prime objective for energy policy at national and international levels. Because the residential and commercial energy consumption has steadily increased reaching figures between 20% and 40%. The use of thermal insulation of the building envelope is one of the most currently requested solutions to reduce this energy consumption. Phase Change Materials (PCM) have received increased attention due to their ability to store large amounts of thermal energy within narrow temperature ranges. This property makes them ideal for storage of passive heat in the building envelopes. An experimental study was conducted to analyze the influence of PCM in the construction of exterior walls. Two test cells are constructed in the Faculty of Science Ain Chock, Casablanca. One is equipped with a 0.56 cm layer of PCM on its roof while the second is a reference cell without PCM. The results presented for the period from 8 th to 10 th July 2014 show that the integration of PCM layer reduces the amplitude of instantaneous heat flux through the horizontal wall. The indoor and the internal vertical wall temperatures, in the case of the cell with PCM, are relatively decreased compared to those of the reference one. For example, the maximum deviation between the indoor temperatures of the cubicles is not more than 1.5˚C while the one on the west faces reaches 3˚C by mid day. Also the inclusion of a layer of PCM shifts the time of peak load and discharge.
PCM SOLAR AIR HEAT EXCHANGER AND ITS VENTILATION PREHEATING EFFECTIVENESS
ijetrm journal , 2020
This article presents a PCM solar air heat exchanger integrated into ventilated window developed to maximize the use of the solar energy to pre-heat the ventilated air. The system is designed to improve the indoor air quality and thermal comfort by continuous pre-heated air supply at a reduced energy use through the capturing and storing of solar energy. This study examines the thermodynamic behavior of the system both experimentally and numerically. This entails a full-scale experiment in climate boxes to study the thermal storage and heat release ability of the facility. Accordingly, a numerical model combining heat transfer and buoyancy derived laminar flow and nonlinear thermal properties of the PCM is built and validated with the experimental data. The model is then used for configuration optimization of the PCM solar air heat exchanger to maximize the solar energy storage and the ventilation pre-heating effectiveness. The results show that for a 6-h solar charging period, the optimum PCM plate depth is 90 mm and the optimum air gap thickness is 6 mm. The same configuration can be used for both summer night cooling and winter solar energy storage applications. The total stored/released latent heat after one charging period is 93.31 MJ/m 3. INTRODUCTION Building energy use for ventilation and HVAC systems amount to more than one-third of the total energy use in industrial countries and about 40% of the total energy use in Europe, and it shows growing trends as a result of increased thermal comfort requirements and climate changes. It has become a burden to the environment and the fossil fuel resources. To diminish the fuel consumption and carbon dioxide emission caused by building energy use, it is necessary to implement innovative technical solutions and renewable energy resources in the built environment. Many researchers have studied renewable energy such as solar energy applied in building energy systems to reduce the traditional building energy use. Excess renewable energy is often stored in thermal energy storage (TES) facilities with the advantages of grid peak shifting, building energy conservation, and the building thermal mass level improvement. Phase change material (PCM) applied in TES is one of the most promising solutions for renewable energy storage and has recently drawn much attention within the scientific community .Unlike the materials with only sensible energy storage, PCM releases/absorbs large amounts of latent heat during its phase transition in a small temperature range. The heat capacity of PCM during the phase transition period is much higher than the conventional building materials. The high energy density of the PCM offers a large heat storage ability with a relatively small storage volume, which makes it a good candidate for TES With adequate design and choices, the phase transition of the material occurs within the range of indoor thermal comfort, which allows direct applications of PCM in the building environment[2]-[4]. ventilative heating or cooling systems integrating PCM for thermal storage is a common building application, which
2019
As a key consumer of energy, and producer of greenhouse gas emissions, the building industry can play a pivotal role in reducing the global energy and carbon footprint. Thus, the application of passive techniques in buildings has gained particular attention. These techniques, with minimal auxiliary energy load, can mediate between the external climate and comfortable indoor conditions, while providing an aesthetically pleasing indoor environment. Thermal energy storage is considered an essential component when using passive techniques. The primary aim of energy storage incorporated into buildings using passive strategies is to implement approaches for efficiently controlling the time lag between building energy demand and outdoor energy sources. Examples of passive strategies are advanced thermal energy storage (TES) and night ventilation (NV). Phase change materials (PCMs) as a salient example of advanced TES, have received remarkable attention for their use in energy-efficient bui...