Optimization of building thermal design and control by multi-criterion genetic algorithm

The design of buildings is a multi-criterion optimization problem, there always being a trade-off to be made between capital expenditure, operating cost, and occupant thermal comfort. This paper investigates the application of a multi-objective genetic algorithm (MOGA) search method in the identification of the optimum pay-off characteristic between the energy cost of a building and the the occupant thermal discomfort. Results are presented for the pay-off characteristics between energy cost and zone thermal comfort, for three design days and three building weights. Inspection of the solutions indicates that the MOGA is able to find the optimum pay-off characteristic between the daily energy cost and zone thermal comfort. It can be concluded that multi-criterion genetic algorithm search methods offer great potential for the identification of the pay-off between the elements of building thermal design, and as such can help inform the building design process.     

计算机模拟在建筑节能设计中的应用

依据DBJ13—62—2004《福建省居住建筑节能设计标准实施细则》,从节能率、成本、建筑热舒适性、节能方案适宜性等方面对比分析了规定性指标节能设计法与动态权衡计算设计法的优劣。得出计算机仿真模拟技术在建筑节能设计中应用的重要性。     

Optimization of energy consumption in buildings with hydronic heating systems considering thermal comfort by use of computer-based tools

The paper deals with an optimization of parameters, which influence the energy and investment cost as well as the thermal comfort. The parameters considered in this study are: the insulation thickness of the building envelope, the supply-water temperature and the heat exchange area of the radiators. A combination of the building energy simulation software EnergyPlus ¹ and the generic optimization program GenOpt (see footnote 1) has been used for this purpose. The paper presents the application of a one-objective optimization algorithm solving the problems with two objectives, because the optimization algorithm is one-objective and the problem has two objectives, which are minimal total costs and satisfied thermal comfort. The total costs represent the sum of energy consumption and the investment costs. The thermal comfort is represented by Predicted Percentage of Dissatisfied (PPD) in this study. The optimization is used to determine the values of parameters that give the lowest sum of investment and energy cost, under the condition that the thermal comfort is satisfied. In addition, the optimization processes show the mutual influence of parameters on both the total cost and the thermal comfort.     

热力学下的冀北传统民居更新设计方法研究

传统民居更新保护中热力学问题是一个重要的研究方向。本文从热环境影响下的传统建造方法、舒适度边界与农村能源特征,研究冀北民居"空间、表皮、能源"三者协同节能的关系,实现传统形态整体优化。并以本地传统民居项目进行"低技术、低能耗、低造价"设计实践分析,形成系统的传统民居"热力学"设计思路,为冀北传统民居保护提供可行性的设计模式。     

空调室内气流组织与建筑节能

论述了室内环境热舒适性的重要性,以及空调气流组织对室内环境热舒适性和建筑节能的影响。空调室内气流组织不合理不仅会导致人员热舒适性降低,而且还会影响工作效率和身心健康,同时,还会导致设备初投资和运行费用的增加。室内空调气流组织优化不仅要考虑室内人员环境的热舒适性,同时,要考虑降低空调运行能耗以实现建筑节能。     

Thermo-economic optimization of rooftop unit’s evaporator coil for energy efficiency and thermal comfort

In this paper, the optimization-simulation approach is proposed to investigate energy saving potential of an air-cooled direct expansion rooftop package air conditioning system by refining the model of the HVAC system components and deriving optimal configuration for evaporator coil subject to technical constraints. In this method the frontal area of the evaporator coil is maintained as constant and the variation of other geometrical parameters on the thermal and economical performance of the system is investigated. An actual air-cooled rooftop package of a real-world commercial building in hot and dry climate conditions is used for experimental data collection. Both inputs and outputs are measured from the field monitoring in two summer weeks. Based on the mathematical models and using collected data, modules incorporating the proposed optimal redesign procedure were embedded in a transient simulation tool. A mixed heuristic- deterministic optimization algorithm was implemented in the transient tool to determine the synthesis and design variables that influence the cost and energy efficiency of each configuration. Available experimental results were compared to predicted results to validate the model. Afterwards, the computer model was used to predict how changes in cooling coil geometry would affect the building thermal comfort, the cost and energy consumption of the system.     

Multiobjective optimization of building design using TRNSYS simulations,genetic algorithm,and Artificial Neural Network

Building optimization involving multiple objectives is generally an extremely time-consuming process. The GAINN approach presented in this study first uses a simulation-based Artificial Neural Network (ANN) to characterize building behaviour, and then combines this ANN with a multiobjective Genetic Algorithm (NSGA-II) for optimization. The methodology has been used in the current study for the optimization of thermal comfort and energy consumption in a residential house. Results of ANN training and validation are first discussed. Two optimizations were then conducted taking variables from HVAC system settings, thermostat programming, and passive solar design. By integrating ANN into optimization the total simulation time was considerably reduced compared to classical optimization methodology. Results of the optimizations showed significant reduction in terms of energy consumption as well as improvement in thermal comfort. Finally, thanks to the multiobjective approach, dozens of potential designs were revealed, with a wide range of trade-offs between thermal comfort and energy consumption.     

HVAC system optimization for energy management by evolutionary programming

Energy management of heating, ventilating and air-conditioning (HVAC) systems is a primary concern in building projects, since the energy consumption in electricity has the highest percentage in HVAC among all building services installations and electric appliances. Without sacrifice of thermal comfort, to reset the suitable operating parameters, such as the chilled water temperature and supply air temperature, would have energy saving with immediate effect. For the typical commercial building projects, it is not difficult to acquire the reference settings for efficient operation. However, for some special projects, due to the specific design and control of the HVAC system, conventional settings may not be necessarily energy-efficient in daily operation.In this paper, the simulation-optimization approach was proposed for the effective energy management of HVAC system. Due to the complicated interrelationship of the entire HVAC system, which commonly includes the water side and air side systems, it is necessary to suggest optimum settings for different operations in response to the dynamic cooling loads and changing weather conditions throughout a year. A metaheuristic simulation–EP (evolutionary programming) coupling approach was developed using evolutionary programming, which can effectively handle the discrete, non-linear and highly constrained optimization problems, such as those related to HVAC systems. The effectiveness of this simulation–EP coupling suite was demonstrated through the establishment of a monthly optimum reset scheme for both the chilled water and supply air temperatures of the HVAC installations of a local project. This reset scheme would have a saving potential of about 7% as compared to the existing operational settings, without any extra cost.     

三联供与冰蓄冷耦合的复合系统优化设计

本文建立了一个冷热电三联供与冰蓄冷耦合的复合系统优化数学模型,以年总运行成本最小为目标函数,综合考虑了经济性、环保性、节能性评价指标对系统的影响。最后以上海某综合型超高层建筑为研究对象,利用LINGO软件进行多目标优化计算,提出了三联供耦合冰蓄冷系统的设备优化容量以及全年运行策略优化方案,并分析了电、气价格及二氧化碳排放税对系统的影响。     

Impact of adaptive comfort criteria and heat waves on optimal building thermal mass control

This article investigates building thermal mass control of commercial buildings to reduce utility costs with a particular emphasis on the individual impacts of both adaptive comfort criteria and of heat waves. Recent changes in international standards on thermal comfort for indoor environments allow for adaptation to the weather development as manifested in comfort criteria prEN 15251.2005 and NPR-CR 1752.2005 relative to the non-adaptive comfort criterion ISO 7730.2003. Furthermore, since extreme weather patterns tend to occur more frequently, even in moderate climate zones, it is of interest how a building's passive thermal storage inventory responds to prolonged heat waves. The individual and compounded effects of adaptive comfort criteria and heat waves on the conventional and optimal operation of a prototypical office building are investigated for the particularly hot month of August 2003 in Freiburg, Germany. It is found that operating commercial buildings using adaptive comfort criteria strongly reduces total cooling loads and associated building systems energy consumption under conventional and building thermal mass control. In the case of conventional control, total operating cost reductions follow the cooling loads reductions closely. Conversely, the use of adaptive comfort criteria under optimal building thermal mass control leads to both lower and slightly higher absolute operating costs compared to the optimal costs for the non-adaptive ISO 7730. While heat waves strongly affect the peak cooling loads under both conventional and optimal building thermal mass control, total cooling loads, building energy consumption and costs are only weakly affected for both control modes. Passive cooling under cost-optimal control, while achieving significant total cost reductions of up to 13%, is associated with total energy penalties on the order of 1–3% relative to conventional nighttime setup control. Thus, building thermal mass control defends its cost saving potential under optimal control in the presence of adaptive comfort criteria and heat waves.     

冷吊顶系统的研究进展

冷吊顶技术是一种节能的空调新技术。其优越性主要表现在它极佳的热舒适性、较低的能耗和运行费用上。本文综述了国内外对冷吊顶技术的研究进展情况。分别从空调系统的工况参数和热环境指标方面，评价了冷吊顶系统优于传统空调系统的热舒适性；从风机能耗、辐射传热特性和供冷工质的替代等方面，分析了冷吊顶空调系统独特的节能优势。就冷吊顶系统的模拟研究方法，评述了几种模拟模型、应用软件和实验方法等。并建议国内相关行业的研发人员在完善冷吊顶的模型模拟和实验方法后，应着重冷吊顶产品的设计方法、材料替代和制造工艺的研究。     

居住建筑室内热环境低能耗营造的多目标设计方法

人居环境改善涉及重大民生问题,节能减排是国家重大战略。因此,有必要寻求合理的居住建筑设计方法,使设计方案既满足居民的室内热舒适需求又能降低建筑能耗。基于多目标遗传优化算法,建立能够对建筑设计方案进行优化、实现增加室内热舒适时间比例的同时降低建筑全年冷热负荷的居住建筑设计双目标优化模型。最后,以重庆典型户型为实例进行优化,优化后的设计方案建筑全年冷热负荷降低了47.74%,室内热舒适时间比例提高了3.94%,验证了模型的可行性和准确性。     

Economic evaluation of the building envelope and operation period of heating system in terms of thermal comfort

One of the most important properties of a passively designed building is to provide thermal comfort conditions for users with a minimum heating energy cost. Therefore, primary parameters affecting heating energy consumption should be determined correctly during the design stage. Building envelope and operation period of the heating system are important parameters affecting total heating energy consumption in the building. In this study, an approach for the determination of the most convenient building envelope-operation period combination in relation to the life cycle cost and climatic comfort is proposed. For the application of the approach, total heat loss and life cycle cost of the building envelope-operation period combinations of a sample building, which is heated intermittently and used during underheated period of the year were calculated and combinations which provide thermal comfort during the occupation period with the minimum life cycle cost are determined as a most convenient combinations. This study is carried out in Istanbul, which is representative city for temperate-humid zone of Turkey.     

住宅建筑气候适应性优化设计研究

以中国5个典型城市的气候条件为例，提出住宅建筑气候适应性优化设计流程。基于Grasshopper参数化性能分析平台，和Ladybug/Honeybee环境分析插件，以热环境舒适度模型、建筑能耗模型和建筑生命周期成本模型为目标函数进行优化分析。发现哈尔滨和北京气候条件下，住宅建筑应选择nZEB'（权衡最优）设计参数，而上海、昆明和深圳气候条件下，C-O（成本效益最优）解决方案比nZEB（节能最优）解决方案的综合效益更好。基于参数化性能模拟的多目标优化可以有效辅助住宅建筑的气候适应性设计研究。     

置换通风的发展及研究现状

基于置换通风舒适、健康和节能的显著特点,本文回顾了置换通风的发展历程,从室内空气品质和节能等方面阐述了国内外置换通风的研究现状。气流组织、热舒适性和污染物分布是影响置换通风室内空气品质的主要因素,因而论文主要从置换通风的两个显著特性：热力分层和垂直温度梯度的角度讨论了室内热舒适性影响因素和研究现状,从颗粒和气体污染物的分布情况论述污染物对室内空气品质的影响,根据置换通风的气流特性,提出可以把室内污染物分为热源和冷源污染物进行研究;最后简要介绍了置换通风节能的情况和优势。     

由热舒适指标及空调设计计算参数谈节能

以PMV—PPD评价指标和ASHRAE舒适标准为理论依据，对空调设计舒适度和空调节能进行了讨论，认为应研究适于我国居民的热舒适标准，而后提出一些节能措施以及方向。     

室内平均辐射温度的建筑设计与调节

通过对人体热舒适和室内平均辐射温度及围护结构内表面温度的分析,从整体环境规划、单体建筑设计方面探讨了对室内平均辐射温度的设计调节措施,并提出了围护结构的节能与人体热舒适改善的一致性。     

Optimum, technical and energy efficiency design of residential building in Mediterranean region

Jordan heavily relies on imported oil and gas for meeting its energy need as the same time the construction sector consumed more than half of the total electricity consumption in Jordan in 2008. In order to provide the occupants with thermal comfort at least cost, applying energy saving measures into early design stage can be significant to achieve this goal.This paper discusses an assessment of best orientation of the building, windows size, thermal insulation thickness from energetic, economic and environmental point of view for typical residential building located in Mediterranean region. The results show that about 27.59% of annual energy consumption can be saved by choosing best orientation, optimum size of windows and shading device, and optimum insulation thickness. The Life Cycle Cost (LCC) is reduced by 11.94%. The specific energy consumption per square meter is 64 kWh/m² a.     

寒冷地区中小型高铁站候车厅夏季热舒适性及节能潜力研究

选取寒冷地区中小型高铁站,采用问卷调查与物理测试结合的方法,研究寒冷地区高铁站候车厅中旅客的热舒适度,得出旅客的中性温度与舒适温度阈值,并进而代入能耗模拟,探究热舒适与建筑能耗耦合作用下的高铁站房夏季节能潜力。研究结果表明,对于夏季高铁站候车厅,旅客中性温度为25.92℃,热舒适区间为22.03~28.43℃。通过中性温度及热舒适区间设置优化,其能降低约5%~11%的制冷能耗;而舒适区间范围内的能耗波动幅度为92 107 k W·h,约占制冷能耗的24.32%,节能效果可观。     

冷却吊顶系统的特性及应用

冷却吊顶由于其高舒适性和节能效果近几年在欧洲应用相当广泛,本文主要介绍冷却吊顶的工作原理,优越性及其空气和水系统的常用设计方法。