Enhanced energy conservation in houses through high performance design

Key design features of high performance houses are investigated for improving energy efficiency in cold climates. Reference dwellings with typical constructions and system designs are compared with high performance houses using the best technology available. The dwellings used for reference are a multi-family apartment building and a single-family detached house, designed according to a mix of Nordic building codes of 2001. The high performance houses designed fulfilled the target requirements of IEA Task 28, Sustainable Solar Housing. Simulations of the buildings are performed using the computer programme DEROB-LTH and results from simulations give the hourly space-heating demand and peak load of the buildings. A comparison of reference houses to high performance solutions shows that the space-heating demand can be reduced by up to 83% for single-family houses and by up to 85% for apartment buildings. The climate data used for all simulations is Stockholm, Sweden. The environmental effects in terms of CO₂ equivalent emissions and use of non-renewable primary energy are quantified for each building type and construction. The energy saving potential of high performance houses in cold climates is demonstrated.     

Modular energy cost optimization for buildings with integrated microgrid

Buildings are becoming suitable for application of sophisticated energy management approaches to increase their energy efficiency and possibly turn them into active energy market participants.The paper proposes a modular coordination mechanism between building zones comfort control and building microgrid energy flows control based on model predictive control. The approach opens possibilities to modularly coordinate technologically heterogeneous building subsystems for economically-optimal operation under user comfort constraints. The imposed modularity is based on a simple interface for exchanging building consumption and microgrid energyprice profiles. This is a key element for technology separation,replication and up-scaling towards the levels of smart grids and smart cities where buildings play active roles in energy management. The proposed coordination mechanism is presented in a comprehensive realistic case study of maintaining comfort in an office building with integrated microgrid. The approach stands out with significant performance improvements compared to various non-coordinated predictive control schemes and baseline controllers. Results give detailed information about yearly cost-effectiveness of the considered configurations,which are suitable for deployment as short-and long-term zero-energy building investments.     

Glazing energy performance and design optimization with daylighting

This study systematically explores the influence of glazing systems on component loads and annual energy use in prototypical office buildings. The DOE-2.1B building energy simulation program, which contains an integrated daylighting model, is used to determine fenestration energy performance in diverse climates. The sensitivity of total energy use to orientation, window area, glazing properties (U-value, shading coefficient, visible transmittance), window management strategy, installed lighting power, and lighting control strategy are all described. We examine the conditions under which daylighting reduces net anual energy use as well as those conditions under which energy use may increase. Combinations of wall and fenestration properties that minimize net energy requirements as a function of climate and orientation are described.     

住宅的空间设计与节能

针对中国建筑能耗的基本情况,提出改善住宅室内热环境是最基本的节能措施,并对住宅的主要空间与建筑节能设计进行了探讨,归纳总结了住宅的五种节能途径,以期为住户提供健康、舒适的生活空间。     

Analysis of feasibility on heating single family houses in rural areas by using sun and wind energy

Households in Lithuania consume about 1/3 of total final consumption of fuel energy. In order to reduce imports of fossil fuel and emissions of dangerous pollutants, solar energy could be used for the above-mentioned needs. That would require large collector areas and volumes for seasonal heat storage. In wintertime the wind speed velocity is much higher than in summertime in Lithuania. Therefore, it is advisable to study meeting the thermal needs of single family houses by combining use of wind and solar energy. To this end analytical research has been made by using deterministic method. The analysis has been carried out for the case when 1 m² of heated room area requires 0.25 m² of solar collector area and 0.5 m² working area of wind turbine rotor. Heat storage is planned for 24 h. By using such a hybrid system during the heating season 42.6–56.2% of heating needs for space and domestic hot water are satisfied. However, for individual days (especially from May to October) a surplus of generated heat is formed and it reaches about 53.6% of space heating needs per year. This relative surplus of energy could be used for transmitting wind power-plant energy to the electric network or in a household and thermal energy can be used for drying agricultural produce, heating greenhouses, open swimming pools and satisfying other needs.     

Life cycle energy of single landed houses in Indonesia

Building enclosures contribute 10–50% of the total building cost and 14–17% of the total material mass. The direct as well as indirect influence of the enclosure materials plays an important role in the building life cycle energy. Single landed houses, the typical houses in Indonesia, have been chosen for this study. The life cycle energy of the house enclosures and energy consumed during their life spans shows intriguing results. The initial embodied energy of typical brick and clay roof enclosures is 45 GJ compared to the other typical walls and roof material (cement based) which is 46 GJ. However, over the 40 years life span of the houses, the clay based ones have a better energy performance than the cement based ones, 692 GJ versus 733 GJ, respectively. The material selection during the design phase is thus crucial since the buildings have at least 40–50 years’ life span.     

陇东地区农宅建筑热工性能调查与节能构造设计

对陇东地区农宅建筑整体节能特性进行了探讨,并对该地区典型农宅建筑热工性能进行了调研分析,综合传统农宅和新农村建筑热工节能方面的优劣,提出建筑节能构造综合设计方案。     

设计与建造一体化成本管理分析

分析了设计与建造一体化模式的优缺点,探讨了该模式中计价特征、造价构成、合同形式选择及造价管理的特点,并从发包方、承包方及审计方三方面,阐述了造价管理的方法及主要环节,有利于促进国内设计—建造模式的快速发展。     

Life cycle assessment applied to the comparative evaluation of single family houses in the French context

A life cycle simulation tool has been developed and linked with thermal simulation. Inventories given in the Oekoinventare database or collected in the European REGENER project are considered to evaluate the environmental impacts of material fabrication and other processes (energy, transport, etc.). An application of this tool is presented here concerning the comparison of three houses: the present construction standard in France (reference), a solar and a wooden frame house. The results of this exercise are presented and its limits are discussed. It seems still difficult to apply life cycle assessment (LCA) to the selection of materials and components. Rather, LCA can be used for the improvement of technical solutions (e.g. increasing the roof insulation in the solar house).     

Feasibility of upgrading the energy performance of recent massive brick houses

Climate change policies imply significant reductions of energy use in buildings. For this, prevailing energy performance standards fall short, notwithstanding the emergence of stricter national building regulations. Regulations cover new built and renovation projects. New built houses that miss the best energy performance are soon candidate for energy upgrading. We investigate the architectural and economic aspects of upgrading recently built detached massive brick houses in Flanders (Belgium). For representing actual building practices, consecutive upgrading steps from lower to higher energy performance levels are considered. Questions addressed are: What is technically feasible in upgrading such houses? Which construction works are easy, which difficult? What are the architectural and financial consequences of a thorough upgrading? The analysis shows that deep energy transformations are financially unacceptable, related to the irrevocable character of investments in energy efficiency attributes of massive brick houses. This confirms that energy performance endowment measures should be designed and implemented at the time of first construction of a building.     

A cost effective approach to design of energy efficient residential buildings

The objective of this study is to identify cost-optimal efficiency packages at several levels of building energy savings. A two-story residential building located in Jordan is selected as a case study. DesignBuilder software is used to predict the annual energy usage of a two-story residence in Irbid, Jordan. Real-time experimental data from a single isolated controlled room was used to verify the proposed model. In addition to energy analysis, the economic, environmental, and social benefits of the proposed design have been investigated. The sequential search optimization approach is used to estimate the minimum cost of the building while considering various design scenarios. In addition, the impact of various energy conservation techniques on residential buildings is assessed, and the payback period for each program is calculated. Ultimately, the optimal combination of design to achieve energy efficiency measures has been identified in several climate regions. The simulations results predict that the annual electricity consumption can be reduced up to 50% if the proper combinations of energy conservation measures are selected at the lowest cost. The payback period is 9.3 years. Finally, energy efficiency measures can lead to a total of 9470 jobs/year job opportunities.The study provide practical framework to link between energy performance criteria and economic goals of building. Linking the energy performance requirements to economic targets provides guidelines for homeowners, contractors, and policymakers for making a suitable decision regarding the retrofitting of existing residential buildings. The study focuses on developing new methodologies that support minimizing costs during a building's lifecycle while maximizing environmental benefits which can not be identified by a series of parametric analyses using individual energy-efficient measures.     

A cost effective approach to design of energy efficient residential buildings

The objective of this study is to identify cost-optimal efficiency packages at several levels of building energy savings.A two-story residential building locate...     

Energy-efficient houses built according to the energy performance requirements introduced in Denmark in 2006

In order to meet new tighter building energy requirements introduced in Denmark in 2006 and prepare the way for future buildings with even lower energy consumption, single-family houses were built with the purpose to demonstrate that it is possible to build typical single-family houses with an energy consumption that meets the demands without problems concerning building technology or economy. The paper gives a brief presentation of the houses and the applied energy-saving measures. The paper also presents results from measurements of the overall energy use, indoor climate and air tightness. Furthermore, results from detailed calculations of the utilization of electricity-related heat gains are presented. Looking at the energy consumption in relation to the new energy requirements, the paper concludes that the single houses can relatively easily keep the future energy demands. The energy consumption of the houses is on a level corresponding to a classification as “low-energy house class 2” or an energy consumption of 75% of the required maximum energy consumption. With minor modifications, some houses could be classified as “low-energy building class 1” corresponding to an energy consumption of only 50% of the required and almost the level of typical passive houses.     

节能创造价值--谈湖南地区住宅建筑的节能设计

本文阐述了湖南地区住宅建筑进行节能设计对使用者、开发商和社会的价值,以及如何在该地区进行住宅建筑节能设计.     

Building leakage,infiltration, and energy performance analyses for Finnish detached houses

This study focuses on the relation between the airtightness of a building envelope, infiltration, and energy use of a typical modern Finnish detached house in the cold climate of Finland. The study is conducted with an empirically tested dynamic IDA-ICE simulation model of a detached house. The effect of several factors, such as Finnish climate and wind conditions, balance of ventilation system and leakage distribution, on infiltration was studied and a simple adapted model for the rough estimation of annual infiltration in Finnish detached houses was determined from the numerical simulation results. The energy impact of infiltration is also studied, taking into account the infiltration heat recovery effect. According to the results, infiltration causes about 15–30% of the energy use of space heating including ventilation in the typical Finnish detached house. The average infiltration rate and heat energy use increase almost linearly with the building leakage rate n₅₀. Finland can be roughly divided into two zones based on the average infiltration rate of detached houses, for which stack-induced infiltration is typically dominant, regardless of the climate zone. The infiltration heat recovery effect is minor in the studied detached house.     

House price indexes: The hedonic technique,and some other methods applied to price movements of single family houses in Sweden

The fact that the quality of goods changes over time has always complicated price index calculations. The hedonic technique was originally developed to tackle this problem. From a theoretical point of view the technique offers the best approach to the estimation of changes in ‘pure’ price of single family houses. It is, however, rather expensive and nowhere in abundant use. The purposes of this paper are on one hand to investigate whether the hedonic method may be substituted for some simpler and cheaper method, and on the other to examine the reliability of the ‘official’ price index of Sweden. This is done by comparing the empirical results of different methods with the price estimates of the hedonic technique. The estimated price changes seem to be very sensitive to the method used and none of the alternative methods presented in the paper is capable of superseding the hedonic technique.     

A bi-level design and operation optimization process applied to an energy centre

This paper presents the methods and results of a bi-level optimization process used to select and size the components of an energy centre as well as to determine their optimal operation. The optimization process used a single-objective optimization of operational control nested within a two-objective optimization of design parameters that minimized capital costs and carbon emissions. Different cases were examined in which the ‘credit’ assigned for the export of excess electricity to the grid was varied. Results are presented including the overall trade-off front, trends amongst design variables, operational schedules for a particular solution, and aggregated parameters like total energy supplied by each device. Constraints on roof area were critical at the design-level, and complex interactions between demand and supply were identified at the operational level. Comparison of the two cases highlights the impact of the export of excess power to the grid.     

Reliability-based design optimization with discrete design variables and non-smooth performance functions: AB-PSO algorithm

The purpose of reliability-based design optimization (RBDO) is to find a balanced design that is not only economical but also reliable in the presence of uncertainty. Practical applications of RBDO involve discrete design variables, which are selected from commercially available lists, and non-smooth (non-differentiable) performance functions. In these cases, the problem becomes an NP-complete combinatorial optimization problem, which is intractable for discrete optimization methods. Moreover, the non-smooth performance functions would hinder the use of gradient-based optimizers as gradient information is of questionable accuracy. A framework is presented in this paper whereby subset simulation is integrated with a new particle swarm optimization (PSO) algorithm to solve the discrete and non-smooth RBDO problem. Subset simulation overcomes the inefficiency of direct Monte Carlo simulation (MCS) in estimating small failure probabilities, while being robust against the presence of non-smooth performance functions. The proposed PSO algorithm extends standard PSO to include two new features: auto-tuning and boundary-approaching. The former feature allows the proposed algorithm to automatically fine tune its control parameters without tedious trial-and-error procedures. The latter feature substantially increases the computational efficiency by encouraging movement toward the boundary of the safe region. The proposed auto-tuning boundary-approaching PSO algorithm (AB-PSO) is used to find the optimal design of a ten-bar truss, whose component sizes are selected from commercial standards, while reliability constraints are imposed by the current design code. In multiple trials, the AB-PSO algorithm is able to deliver competitive solutions with consistency. The superiority of the AB-PSO algorithm over standard PSO and GA (genetic algorithm) is statistically supported by non-parametric Mann-Whitney U tests with the p-value less than 0.01.     

建筑结构优化设计方法及展望

结合建筑结构设计工作中选择合理的结构方案时应遵循的一些基本原则,探讨在进行正确的结构计算时应注意的一些问题,对优化设计综合评价指标体系的建立和使用方法进行研究,并对结构优化设计的发展进行展望.     

夏热冬冷地区住宅的节能设计研究

根据夏热冬冷地区的气候特征，从外墙保温、门窗的保温与节能的措施出发，论述了该地区住宅围护结构的节能设计方法，从而创造良好的室内热环境，节约能源。