Low Energy Consumption Building Research Articles

Study on convective heat transfer coefficient on vertical external surface of island-reef building based on naphthalene sublimation method

The island-reef areas located in southern China have a unique climate—high temperature, high humidity, high concentrations of salt mist, strong solar radiation, small diurnal/annual temperature range and perennial sea breeze, and it is exceedingly diverse with the climate in Chinese inland. In order to prove the simple naphthalene sublimation method for measuring convective heat transfer coefficient (CHTC) is feasible in extreme climate conditions and obtain CHTC recommended value in island-reef areas, the study adopted the research methods to combine field measurement and data statistics. According to taking the measured data from naphthalene sublimation experiment as strong support, predictive formula of CHTC on vertical external surface of island-reef building under low wind velocities was raised to provide convenience for engineering design and validated feasible by comparing with ASHRAE recommend formula based on error analysis. Subsequently, the CHTC predictive formula and the specific wind characteristics in Xisha Islands of China were analyzed together. The results showed that CHTCs had a wide range from 6.22W/m2·Kto 54.66W/m2·K, and the average CHTC of all measured points was 17.30W/m2·K. Additionally, CHTCs on windward were greater than those on leeward. Furthermore, the CHTC predictive formula under low wind velocities raised by this study was precise and reliable, and could guarantee to be applicable for island-reef building more than 55% time no matter which season it was. Consequently, CHTC on vertical external surface of island-reef building under low wind velocities was recommended as 21.51W/m2·K in terms of average level of the whole year. This study can provide convenience for popularizing the simplified method in extreme climate conditions and lay a solid foundation for the design of low energy consumption building in island-reef areas.

Internal heat gain from different light sources in the building lighting systems

EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output) were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

Low energy buildings in Taiwan mountain areas: A weather data analysis

ABSTRACTThe energy consumption of buildings is influenced by the climates tremendously. Taiwan is an island covered with high mountains. Crossed by the tropic of cancer, the basic climates zones include tropical and subtropical climates. In this research, the degree day and degree hour methods were used to analyze 37 weather stations data in mid and high elevation regions of Taiwan collected over 10 years. The WRF model were used to predict summer cooling hours using 26, 28, 30°C as the base temperatures. The research showed that Taiwan has complicated climate zones due to the variations of the elevation. The low air-conditioning load areas in the mid and high elevation regions will be the most suitable areas to design low energy consumption buildings in Taiwan.

Fast POD method to evaluate infiltration heat recovery in building walls

Air infiltration of buildings has a considerable impact on the energy performance of buildings. Permeability or airflow leakage can be evaluated by introducing the Infiltration Heat Recovery (IHR) factor in the energy balance equation. Conventionally, this factor is computed using a Computational Fluid Dynamics (CFD) software, that is time consuming and not very useful for a fast evaluation of balance energy of a building. This article proposes a Reduced-Order model (ROM) approach to evaluate the effect of the permeability of the energy balance for a building. The ROM, based on the well-known Proper Orthogonal Decomposition (POD) method, is developed in the Modelica modeling language. It is successfully applied to the case study of the air infiltration in the low energy consumption building.

Impact of sun patch and three-dimensional heat transfer descriptions on the accuracy of a building’s thermal behavior prediction

A thermal transient numerical model (M3D) which considers the three-dimensional heat transfer through the envelope of a room and the sun patch through a window has been developed and validated in a recent paper. The use of a refined spatial and temporal discretization allows considering more precise interactions between the sun patch projection with the structure and quick time perturbations in the stresses. This is particularly necessary for highly insulated and low energy consumption buildings. In this new paper, M3D is subsequently transformed to simpler configurations, close to classical modelling thermal building simulation software that neglects the sun patch and the 3D heat transfer, in order to quantify the main contributions of this model. A first configuration is to consider one-dimensional heat conduction for the envelope and the transmitted solar radiation is only projected onto the floor (M1D). A second configuration considers also one-dimensional heat conduction but the transmitted beam radiation falls on each wall or floor that is impacted (M1D,sp). Comparison between experimental data and numerical results of these three models shows, as expected, that M1D and M1D,sp are less accurate than M3D. This is particularly true when wanting to evaluate surface temperature distributions or heating power evolution in winter.

Experimental monitoring and post-occupancy evaluation of a non-domestic solar building in the central region of Argentina

Previous experience in designing and monitoring bioclimatic buildings in central Argentina suggests that their thermal behavior is a matter of concern and that further research is needed. Thus, the objectives of this work are: to describe the design and the post-occupancy evaluation of a new non-domestic solar building in a continental semiarid region of central Argentina (37°38′ latitude S, 63°34′ longitude, 175m above sea level), to analyze the building's hygrothermal and energy performance, and to estimate the PMV and PPD. The design guidelines were: to minimize the consumption of conventional energy in thermal-lighting conditioning, to use traditional technology, to maximize the thermal comfort, and to reach an extra-cost lower than 10%. The post-occupancy monitoring of the building was performed along one complete year (August 9th 2011–August 18th 2012). Data-loggers were installed in each functional area to sense the indoor temperature and relative humidity at time steps of 10min. A meteorological station was installed near the building. The experimental results showed that during winter the average temperature in the areas of permanent use was 20.3°C (average outdoor temperature: 10.1°C) and the heating energy consumption was around 73.5kWh/m2. During summer the average indoor temperature in the building was 26.9°C, 1.7°C below the outdoor temperature average (28.6°C); cooling systems were turned on when the indoor temperature reached 28°C, at approximately 11:30 AM, when the outdoor air temperature exceeded 30°C. Mechanical cooling consumed around 59% of the daily electricity consumption. The PDD results obtained for winter and summer representative days meet the requirements of ISO Norm 7730. Heating and cooling energy saving was around 63% and 76.5% respectively. The monitoring showed that the thermal behavior and energy performance met the expectations of both designers and users, and it is considered satisfactory and promising for low-energy consumption buildings.

Development of Intelligent Façade Based on Outdoor Environment and Indoor Thermal Comfort

Abstract In the last decades, the development of innovative solutions is considered as a prominent issue for achieving sustainability within the built environment. Facades are crucial to energy consumption and comfort within buildings. Incorporating intelligence in their design is an effective way to achieve low energy consumption buildings. The ability of specific facade systems to work reliably and effectively is one of the challenges towards sustainability. This study presents the state of art for intelligent facades at different outdoor environment in different climates. In addition the indoor environmental parameters such as thermal comfort, indoor air quality and visual comfort are outlined. The study concluded that intelligent facades in buildings and indoor thermal comfort require more development targeting low energy buildings and thermal comfort.

Concept Project of Zero Energy Building

The acute problem of carbon dioxide emissions reduction into the atmosphere becomes more important due to the fact of the global climate change. Housing stock consumes 30 to 40% of all energy resources, according to various estimates. As the result, it is possible to get carbon dioxide atmosphere emissions reduction due to energy consumption reduction. The problem of housing stock energy efficiency improvement becomes very important. Transition to low energy consumption buildings construction becomes a trend which in the nearest future will transform to the task of Applied Research in the field of design and construction. Such exploration object is to design buildings with zero energy consumption or close, which is planned construct on the site of the Polytechnic University. The novelty of the project consists in an integrated approach of the house design, which will be entirely autonomous and independent from the urban networks.

Heating and Cooling Load Characteristics Comparison between Normal Building and Low Energy Consumption Building

In this research, a normal building and low energy consumption building were chosen to compare and analyze heating and cooling load characteristics. Firstly, the abstract of two buildings were carried out. Secondly, methodology of measurement and calculation was researched. At last the heating and cooling load of two buildings was examined using this methodology.

Inter-seasonal Heat Storage in Low Energy House: From Requirements to TESS Specifications

This paper aims at providing sizing information concerning a thermal energy storage system (TESS) in the case of a low energy consumption building (< 50 kWh/m2.y). Numerical simulations for a reference individual building were run for twenty-three different cities in Europe. As power supply is the limiting factor in most of the TESS, results focuses on design power estimation. A clear correlation between power demand and heating degree hours (HDH) is presented. But as the design of a TESS based on maximum power is too ambitious, the analysis goes further. It gives the distribution of sorted power demand values as a function of HDH in the form of a power sizing chart. The purpose of this chart is to provide specification requirements for the sizing of a thermal storage system intended to partially cover power demand of a low energy residential house.

Specification requirements for inter-seasonal heat storage systems in a low energy residential house

This paper aims at providing sizing information concerning a thermal storage system in the case of a low energy consumption building (<50kWh/m2y). Numerical simulations for a reference individual building were run for 23 different cities in Europe. Results show a clear correlation between annual heat demand Qy and annual heating degree-day (HDD): Qy=f1(HDD). There is also a good correlation between power demand and HDD. But as heat coverage of the entire heating period may be too ambitious, the analysis goes further. It presents a correlation between heating demand Q and HDD as a function of the storage system autonomy t of the form Q=1-exp-tτ×Qy with τ=f2(HDD). It also gives the absolute distribution of sorted power demand values as a function of HDD in the form of a power sizing chart. The purpose of this chart is to provide specifications for the sizing of a thermal storage system intended to partially cover energy needs and power demand of a low energy residential house.

The Strategies of Passive Energy-Efficiency Design in Low Energy Building

This paper briefly analyzes the structure and conservation approaches of building energy consumption, analyzes the forming reason and influence factors of heating and air-conditioning energy consumption and proposes the passive energy conservation designing strategies of low energy consumption building. Through the passive methods of building design, envelop enclosure and planning landscape, the goal of last year building low energy conservation can be achieved.

Life Cycle Assessment of a passive house in a seismic temperate zone

This paper presents the results of a detailed LCA study of a low-energy consumption building (thermal energy for heating equal to 11kWh/m2year) located in Perugia, Italy, according to European ISO 14040 and 14044. The building matches the criteria of environmental sustainability and bio-architecture, complying with the “PassivHaus” standard. All life cycle phases were included in the research: acquisition and production of materials, on-site construction and use/maintenance, demolition and material disposal (100% landfilling and demolition with waste recycling). A life span of 70 years was considered.The research was therefore focused on cradle-to-grave life, based on data collected by authors, integrated with data from the literature. In particular the study was carried out to analyze: the benefits due to the use of recycled materials, a solar PV (during the utilization years) and the final demolition of the building. The LCA modeling was performed using the SimaPro software application, connected to the ecoinvent database. The results show that applying energy saving measures (highly insulated building envelope and passive-house standard, solar PV, waste recycling and recycled products in pre-production phase) could significantly decrease the impact of modern dwellings, with the consciousness that new ways of building do not always provide a positive environmental outcome.

Concerning the Application of Grass Brick House in Rural Construction - Make Shangdianzi Village in Jilin Province as an Example

The grass brick house is made of the grass brick which is compressed by rice (Michael) straw and built to house. It has good heat preservation performance, low energy consumption and production building convenient, and it is harmless to the environment, protecting land and other characteristics. It meets the needs of using new building materials into the rural residential construction. To make this new type energy saving and emission reduction technology on grass brick building can improve, promote to the more rural, and provide the reference which can better service for new countryside construction on using building materials.

Hourly Heating Load Prediction of Radiant Floor Heating System Based on the BP Neural Network

An improved error transfer BP neural network model is use to predict the dynamic heating load in a house or a dwelling unit with the character of hour heating load. Compared with the conventionally physical model, the computation consumption is reduced greatly for the less number of the parameters by improving the error transfer ways. The numerical simulation and experimental measure in a low energy consumption building of Dalian city are performed and the BP neural network model was based entirely on the field survey data. The results show that the simulated results are well agreed with the experimental data and the averaged relative error is less than 5%. Furthermore, this improved model can predict accurately hour heating load during the course of next 24 hours and it is favorable for predicting the short time heating load problems.

Sustainable Buildings: An Ever Evolving Target

Environmental considerations have called for new developments in building technologies to bridge the gap between this need for lower impacts on the environment and ever increasing comfort. These developments were generally directed at the reduction of the energy consumption during operations. While this was indeed a mandatory first step, complete environmental life cycle analysis raises new questions. For instance, for a typical low thermal energy consumption building, the embodied energy of construction materials now becomes an important component of the environmental footprint. In addition, the usual practice in life cycle analysis now appears to call for some adaptation—due to variable parameters in time—to be implemented successfully in building analysis. These issues bring new challenges to reach the goal of integrated design, construction, commissioning, operation, maintenance, and decommissioning of sustainable buildings.

Instalaciones del Pabellón de España en la Expo 2008

Is the subject of this article describing the technical installations in the Spanish Pavilion for the International Exhibition “Water and sustainable development” in Saragossa 2008. This description follows the design process until it achieves a low energy consumption building, not only on account of the materials and constructive systems employed, but also on account of the energy efficiency of the installations proposed. For this reason, it is studied from the global siting of the spaces required for installations, to the principal installations, so that the reader can understand the individual functioning of the each, independently and in its relationship to the whole. As one can confirm throughout the article, we are dealing with a work of architecture that optimally integrates passive energy savings with innovative installations technologies, achieving an exemplary icon–given the media importance of an event like an international exhibition–for sustainable architecture (rather than ‘bioclimatic’ architecture).

Natural Ventilation - A New Method Based on the Walton Model Applied to Cross-Ventilated Buildings having Two Large External Openings

In order to provide comfort in a low energy consumption building, it is preferable to use natural ventilation rather than HVAC systems. To achieve this, engineers need tools that predict the heat and mass transfer between the building's interior and exterior. This paper presents a method implemented in some building software, and the results are compared to CFD. The results show that the knowledge model is not sufficiently well described to identify all the physical phenomena and the relationships between them. A model was developed which introduces a new building-dependent coefficient allowing the use of Walton's model, as extended by Roldan to large external openings, and which better represents the turbulent phenomena near large external openings. The formulation of the mass flow rates was inversed to identify modelling problems. It appears that the discharge coefficient is not the only or best parameter to obtain an indoor static pressure compatible with CFD results, or to calculate more realistic mass flow rates.

Energy and environmental comparison of three variants of a family house during its whole life span

The aim of this study is to analyse and compare three variants of a family house in order to evaluate the total environmental impacts produced during the whole building life cycle. The first variant corresponds to the standard in force in Switzerland, the second alternative to the requirements of a quality control label for houses with low energy consumption and the third case is a very low energy consumption building. The three variants have the same architectural aspect but different insulation thicknesses and types, different energy production systems and the use of different renewable energies. The calculation of the environmental impacts is carried out by means of a life cycle analysis, which includes not only the impact related to the energy consumption during the occupancy stage, but also the materials manufacture, transport, replacement and elimination at the end of the building lifetime. The results are expressed with the Swiss and the UCTE (Union for the Co-ordination of Transmission of Electricity) electricity mix to analyse how they influence the building impact.