AN INNOVATIVE COOLING ROOF REDUCING THE ENERGY DEMAND FOR A NON-RESIDENTIAL BUILDING IN TROPICAL CLIMATE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mauro Rodolfo Cepeda Ortiz
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Residential Building ◽  
Design Strategies ◽  
Building Roof ◽  
Correct Orientation ◽  
Energy Demands ◽  
Tropical Climates ◽  
Roof Design ◽  
Cooling Loads

In tropical climates, high temperatures and high levels of humidity, coupled with inadequate design of buildings, lead to an increase in thermal loads. The roof is the element of the building that receives the greatest amount of solar radiation throughout the year. As a result, the roof receives excessive thermal gain, which is then transmitted to the rest of the building and leads to an increase in final energy demands. Much of this can be solved with passive design strategies. With respect to the main problem of the building roof, natural ventilation can provide improvements in reducing temperatures in this area and the structure below. First, through correct orientation, a reduction of the building’s annual energy consumption by 24.32% was achieved. Secondly, by applying different configurations of the roof a reduction of 78.09% in roof cooling loads was obtained. This was brought about through a combination of optimization of the roof design for natural ventilation and the application of reflective materials with a U value of 0.13 W / mK. From the second scenario it was reduced by 14.74% with the applied strategy.

scholarly journals Experimental Data and Simulations of Performance and Thermal Comfort in a Typical Mediterranean House

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3311
Author(s):  
Víctor Pérez-Andreu ◽  
Carolina Aparicio-Fernández ◽  
José-Luis Vivancos ◽  
Javier Cárcel-Carrasco
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Thermal Characterization ◽  
Energy Performance ◽  
Building Stock ◽  
Energy Demands ◽  
Dwelling House ◽  
Account Standard

The number of buildings renovated following the introduction of European energy-efficiency policy represents a small number of buildings in Spain. So, the main Spanish building stock needs an urgent energy renovation. Using passive strategies is essential, and thermal characterization and predictive tests of the energy-efficiency improvements achieving acceptable levels of comfort for their users are urgently necessary. This study analyzes the energy performance and thermal comfort of the users in a typical Mediterranean dwelling house. A transient simulation has been used to acquire the scope of Spanish standards for its energy rehabilitation, taking into account standard comfort conditions. The work is based on thermal monitoring of the building and a numerical validated model developed in TRNSYS. Energy demands for different models have been calculated considering different passive constructive measures combined with real wind site conditions and the behavior of users related to natural ventilation. This methodology has given us the necessary information to decide the best solution in relation to energy demand and facility of implementation. The thermal comfort for different models is not directly related to energy demand and has allowed checking when and where the measures need to be done.

scholarly journals A short review on passive strategies applied to minimise the building cooling loads in hot locations

2021 ◽  
Vol 15 (2) ◽  
pp. 20-30
Author(s):  
Qudama Al-Yasiri ◽  
Márta Szabó
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Phase Change Materials ◽  
Weather Conditions ◽  
Short Review ◽  
Building Energy ◽  
Passive Strategies ◽  
Shading Devices ◽  
Building Cooling ◽  
Cooling Loads

Cooling and air-conditioning systems are responsible for the highest energy consumption in buildings located in hot areas. This high share does not only increase the building energy demand cost but also increases the environmental impact, the topmost awareness of the modern era. The development of traditional systems and reliance on renewable technologies have increased drastically in the last century but still lacks economic concerns. Passive cooling strategies have been introduced as a successful option to mitigate the energy demand and improve energy conservation in buildings. This paper shed light on some passive strategies that could be applied to minimise building cooling loads to encourage the movement towards healthier and more energy-efficient buildings. For this purpose, seven popular passive technologies have been discussed shortly: multi-panned windows, shading devices, insulations, green roofing, phase change materials, reflective coatings, and natural ventilation using the windcatcher technique. The analysis of each strategy has shown that the building energy could be improved remarkably. Furthermore, adopting more passive strategies can significantly enhance the building thermal comfort even under severe weather conditions.

scholarly journals Application of Phase Change Materials and Conventional Thermal Mass for Control of Roof-Generated Cooling Loads

2020 ◽  
Vol 10 (19) ◽  
pp. 6875
Author(s):  
Jan Kośny ◽  
William Anthony Miller ◽  
David Yarbrough ◽  
Elisabeth Kossecka ◽  
Kaushik Biswas
Keyword(s):  
Energy Demand ◽  
Phase Change Materials ◽  
Peak Load ◽  
Thermal Response ◽  
Climatic Conditions ◽  
Thermal Mass ◽  
Design Strategies ◽  
Response Characteristics ◽  
Intense Solar Radiation ◽  
Cooling Loads

Among all of the internal fabric and external enclosure components of buildings, sloped roofs and adjacent attics are often the most dynamic areas. Roofs are exposed to high temperature fluctuations and intense solar radiation that are subject to seasonal changes in climatic conditions. Following the currently rising interests in demand-side management, building energy dynamics, and the thermal response characteristics of building components, this paper contains unpublished results from past studies that focused on innovative roof and attic configurations. The authors share unique design strategies that yield significant reduction of daytime roof peak temperatures, thermal-load shavings, and up to a ten-hour shift of the peak load period. Furthermore, advance configurations of the roofs and attics that are discussed in this paper enable over 90% reductions in roof-generated peak-hour cooling loads and sometimes close to 50% reductions in overall roof-generated cooling loads as compared with traditionally constructed roofs with the same or similar levels of thermal insulation. It is expected that the proposed new roof design schemes could support the effective management of dynamic energy demand in future buildings.

scholarly journals Thermal Diagnostics of Natural Ventilation in Buildings: An Integrated Approach

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4556 ◽  
Author(s):  
Joanna Ferdyn-Grygierek ◽  
Andrzej Baranowski ◽  
Monika Blaszczok ◽  
Jan Kaczmarczyk
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Residential Building ◽  
Integrated Approach ◽  
Airflow Rate ◽  
The Real ◽  
Heat Demand ◽  
Design Values ◽  
The Difference

Diagnostics of natural ventilation in buildings is problematic, as the airflow rate changes considerably over time. One constant average airflow is usually assumed when calculating energy demand for a building, however, such a simplification could be fraught with considerable error. The paper describes a comprehensive methodology for the diagnostics of a natural ventilation system in a building and its practical application. Based on in situ measurements and simulations in two existing buildings (dwelling house and school) in Poland, the real values of the ventilating airflows were analyzed and resulting heat demand was compared with the design values. The pros and cons of various methods for evaluation of natural ventilation are discussed. The real airflow was determined by measurements in a ventilation grille or by a tracer gas concentration decay method. The airtightness of the buildings’ envelope was evaluated based on the fan pressurization test. The last stage entailed computer simulations of air exchange in buildings using CONTAM software. The multizone models of the buildings were calibrated and verified with existing measured data. Measured airflow in a multifamily house was small and substantially deviated from the Polish standard. In case of a school, the air flow rate amounted to an average of 10% of the required value. Calculation of the heat demand for ventilation based on the standard value of the airflow led to a considerable overestimation of this value in relation to the real consumption. In the analyzed cases, the difference was 40% for the school and 30% for the residential building.

The Energy Saving Effect of Natural Ventilation for Residential Building in Guangzhou

2011 ◽  
Vol 121-126 ◽  
pp. 597-601
Author(s):  
Cui Cui Qin ◽  
Li Hua Zhao
Keyword(s):  
Wind Speed ◽  
Energy Saving ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Residential Building ◽  
Air Conditioning System ◽  
Effective Measure ◽  
Rate Of Cooling ◽  
Saving Effect ◽  
Cooling Loads

Natural ventilation is the most effective measure to reduce the cooling energy consumption, but it is quite difficult to control and quantitatively assess the natural ventilation. A method was developed with coupling simulation by both software of DeST-h and computational fluid dynamics (CFD) in typical meteorological year (TMY) in Guangzhou. First, the base room temperatures with different air change (ACH) rates of natural ventilated dwelling were simulated with DeST-h. The time period in that the indoor air temperature could meet thermal comfort requirement only by natural ventilation in occupied period was analyzed, in which the wind speed and direction in TMY was obtained for the ventilation environment simulation of rooms in windows and doors switching with the PHOENICS software. The actual air change rates in different rooms in such wind speed and direction were calculated. Also the cooling loads of building in the actual air change rates were simulated with intermittent air conditioning. The air conditioning system operated when the base room temperature was higher than 29°C. Rate of cooling loads reduction was calculated by comparing the result to the baseline, which were the cooling loads of building with 1 ACH. The actual air change rates show that the energy saving effect of natural ventilation was influenced by the windows and doors switching. 61~71.37% of the natural ventilation potential was used in the rooms with windows and doors opened, and 14.06~82.54% of the natural ventilation potential was used in the rooms with windows opened and doors closed. The rate of cooling loads reduction in rooms and building were 0.34~10.50% and 6.14% respectively.

Research on the Natural Ventilation Cooling Effect of Residential Building Based on the CFD and DeST Simulation

2011 ◽  
Vol 374-377 ◽  
pp. 685-689
Author(s):  
Li Hua Zhao ◽  
Cui Cui Qin
Keyword(s):  
Air Conditioning ◽  
Large Scale ◽  
Natural Ventilation ◽  
Residential Building ◽  
Cooling Effect ◽  
Living Room ◽  
Naturally Ventilated Buildings ◽  
Computational Fluid Dynamics Cfd ◽  
Rate Of Cooling ◽  
Cooling Loads

Assessing the energy saving of natural ventilation is difficult, especially for large scale naturally ventilated buildings, due to the lack of deterministic data and method. This paper presents a method, integrating simulation by both software of DeST-h and computational fluid dynamics (CFD) in typical meteorological year (TMY) in Guangzhou, to evaluate quantitatively the natural ventilation cooling effect. The results showed that the cooling effect of natural ventilation was influenced by the windows and doors switching. Air conditioning operating hours reduction in the living room can reach 509h by natural ventilation during the occupied time with the windows and doors opened, which can reach 325h with the windows opened and doors closed. The cooling effect of natural ventilation was more significant in windows and doors opened case than that in windows opened and doors closed case. Annual rate of cooling loads reduction in rooms and building were 0.34~10.50% and 6.14% respectively. It is necessary to organize and design building opening to maximize the natural ventilation using.

scholarly journals The retrofit of ‘70s office buildings curtain walls in London

2021 ◽  
Vol 2042 (1) ◽  
pp. 012154
Author(s):  
A Cirillo ◽  
A Scofone
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Fire Risk ◽  
Office Buildings ◽  
Base Case ◽  
Design Strategies ◽  
Building Stock ◽  
Curtain Wall ◽  
Air Infiltration ◽  
Passive Design

Abstract The built environment accounts for 44% of UK emissions, of which 18% are from non-domestic buildings. Considering that a façade's performance accounts for more than 50% of the energy consumption of a building, the retrofit of a ‘70s curtain wall system is analysed along with common issues such as poor insulation, fire risk, air infiltration and absence of natural ventilation, all of which are known to affect both occupants’ comfort and energy demand negatively. The methodology includes thermal and energy analysis of the Euston tower, results from which are used to inform an analytical model representing a more extensive building stock. Orientation, occupation, window to wall ratio and floor heights are examined as the main factors influencing heat gains, and different passive design solutions are tested to reduce them. Combining these passive design strategies shows a reduction of cooling demand by up to 91% and overheating hours down to 0% from base case to best case, demonstrating how the retrofit of curtain walls in office buildings is essential to cut emissions, reducing energy demand and improving comfort and productivity.

scholarly journals Building form and energy efficiency in tropical climates: A case study of Penang, Malaysia

2021 ◽  
Vol 13 ◽  
Author(s):  
Maryam Mohsenzadeh ◽  
Massoomeh Hedayati Marzbali ◽  
Mohammad Javad Maghsoodi Tilaki ◽  
Aldrin Abdullah
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Demand ◽  
Simulation Analysis ◽  
Energy Performance ◽  
Design Strategies ◽  
Building Shape ◽  
Suitable Form ◽  
Tropical Climates ◽  
Building Form

Abstract Malaysia is a nation that has undergone a massive development based on its abundance of fuel supply. The imbalance ratio between gross domestic products and energy demand clearly indicates the need to promote energy-efficiency strategies in the country. This study investigates the relationship between building shape and energy consumption by considering the control of excessive solar radiation in a tropical climate. In the first step, four basic plan geometries, namely, square, rectangle, triangle and circle shapes, are studied to determine the optimal building shape in terms of energy consumption in Penang, Malaysia. Results of simulation analysis using DesignBuilder software (Version 5.4.0) reveal that the circle is the most suitable form in terms of energy performance. In the second step, all buildings with extended shapes based on the optimal shape obtained from the first step are simulated under the same condition to analyse the thermal behaviour of different building forms. Amongst four alternative extended cases, Case 3 with 90 cm depth and without vertical offset from the top of the window has superior energy performance and sufficient natural daylight. This study contributes to enhance energy efficiency of new buildings by incorporating design strategies in the design process.

scholarly journals CFD investigation of natural ventilation in a family house in Hungary

2021 ◽  
Vol 2069 (1) ◽  
pp. 012095
Author(s):  
Modar Ali ◽  
Ádám László Katona ◽  
István Kistelegdi
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Energy Use ◽  
Residential Building ◽  
Software Tool ◽  
Point Of View ◽  
Ansys Fluent ◽  
Ongoing Research ◽  
Fluent Software ◽  
Computational Fluid Dynamics Cfd

Abstract Buildings are responsible for around 40% of greenhouse emissions globally. The residential building sector is responsible for 24% of energy use. In Hungary, about 800.000 ‘Cube houses’ which date back to the socialist era are still standing. These houses suffer shortages from the energy point of view. This paper presents a new refurbishment approach that attempts to achieve passive cooling with aerodynamic design by integrating the “Venturi disc” which stimulates natural ventilation and night cooling. The work was achieved by using Computational Fluid Dynamics (CFD) simulations using ANSYS Fluent software tool. The implemented building provides lower energy demand and considerably higher comfort in comparison with the typical ‘Cube house’. The building is not only a case study, rather a sustainable model for all the ‘Cube houses’ renewal and further family housing renovations or constructions to reach a higher standard. This paper is a step in an ongoing research project.

scholarly journals Passive Design Strategies for Residential Buildings in Different Spanish Climate Zones

2019 ◽  
Vol 11 (18) ◽  
pp. 4816 ◽  
Author(s):  
Maria-Mar Fernandez-Antolin ◽  
José del Río ◽  
Vincenzo Costanzo ◽  
Francesco Nocera ◽  
Roberto-Alonso Gonzalez-Lezcano
Keyword(s):  
Energy Efficiency ◽  
Energy Demand ◽  
Architectural Design ◽  
Residential Buildings ◽  
Research Work ◽  
Residential Building ◽  
Design Strategies ◽  
Climate Zones ◽  
Building Performance Simulation ◽  
Passive Design

The Passive House (PH) concept is considered an efficient strategy to reduce energy consumption in the building sector, where most of the energy is used for heating and cooling applications. For this reason, energy efficiency measures are increasingly implemented in the residential sector, which is the main responsible for such a consumption. The need for professionals dealing with energy issues, and particularly for architects during the early stages of their architectural design, is crucial when considering energy efficient buildings. Therefore, architects involved in the design and construction stages have key roles in the process of enhancing energy efficiency in buildings. This research work explores the energy efficiency and optimized architectural design for residential buildings located in different climate zones in Spain, with an emphasis on Building Performance Simulation (BPS) as the key tool for architects and other professionals. According to a parametric analysis performed using Design Builder, the following optimal configurations are found for typical residential building projects: North-to-South orientation in all the five climate zones, a maximum shape factor of 0.48, external walls complying with the maximum U-value prescribed by Spanish Building Technical Code (0.35 Wm−2K−1) and a Window-to-Wall Ratio of no more than 20%. In terms of solar reflectance, it is found that the use of light colors is better in hotter climate zones A4, B4, and C4, whereas the best option is using darker colors in the colder climate zones D3 and E1. These measures help reaching the energy demand thresholds set by the Passivhaus Standard in all climate zones except for those located in climates C4, D3 and E1, for which further passive design measures are needed.

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