Thermostat strategies impact on energy consumption in residential buildings

This paper identifies the impact of thermostat strategies on heating and cooling energy consumptions in buildings, thus suggesting the importance of a database for understanding the effect of thermostat settings and for deciding energy-conscious strategies.Using computer simulation, diverse thermostat strategies – change of setback period, change of set-point temperature, and change of setback temperature – were tested parametrically in a typical USA single-family homes, located in two climate zones, namely cold (Detroit, Michigan) and hot-humid (Miami, Florida).Analysis revealed that heating and cooling systems were significant energy-consuming components in each climate zone. Accordingly, heating energy in cold climate zones and cooling energy in hot-humid climate zones have potential for matchingly significant saving. Diverse thermostat strategies (changes of setback period, of set-point, of setback temperature) demonstrated their obvious impacts on such saving. In the cold climate in particular, the heating system showed the most significant energy-saving effect via proper thermostat strategies. Proper setback period, set-point and setback temperature need to be established to achieve energy efficiency in residential buildings.     

The potential of energy flexibility of space heating and cooling in Portugal

This study assesses the potential of energy flexibility of space heating and cooling for a typical household under different geographical conditions in Portugal. The proposed approach modifies the demand through the optimization of the thermostat settings using a genetic algorithm to reduce either operational costs or interaction with the grid. The results show that the used energy flexibility indicator expresses the available potential and that flexibility depends on several factors, namely: i) thermal inertia of the archetypical household; ii) the time of use electricity tariffs; iii) users’ comfort boundaries; and iv) the geographical location of the houses.     

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.     

室内温控器的控制过程及设计

介绍了温控器对室内温度的控制过程、设计中涉及的重要概念,分析了温控器的辅助控制功能及设计中应注意的问题。探讨了可编程温控器对室内温度的控制过程。     

供暖系统调节设备的合理选用

每一个有效节能的供热系统都配有相应的调节控制设备,如自力式流量控制阀,压差控制阀等,随着供热计量收费体制的改革,室内供暖系统装配温控阀后热网如何正确配备控制设备是非常重要的,论述了装配温控阀前后系统的特性变化,指出了选择与温控阀正确配备的控制设备的方法,对供热系统设计和改造有参考意义。     

计量收费后热网运行的特点及控制策略

随着热计量改革的进展,传统供热系统运行模式已经越来越不适用。本文介绍了在新的条件下,装配温控阀前后系统的特性变化,指出了与温控阀正确配备的控制设备;以及相应的热网运行特点和控制策略。     

Evaluating diverse patterns of occupant behavior regarding control-based activities in energy performance simulation

Simulation is recognized as an effective tool for building energy performance assessment during design orretrofit processes. Nevertheless, simulation models yield deviating outcomes from the actual building performance and a significant portion of this deviation originates from the dynamic nature of occupant behavior. Literature on occupant behavior indicates that occupant behavior is not integrated into building energy performance assessment procedures with appropriate resolution, instead they are acceptedas as sumedand fixed data sets that usually represent the presence of occupants. This study attempts to evaluate the effect of diverse patterns of occupant behavior on energy performance simulation for office buildings. Diverse levels of sensitivity of occupant behavior on control-based activities such as using lighting apparatus, adjusting thermostat settings, and presence in space are employed through three diverse occupant behavior patterns. These occupancy patterns are correlated with three identical office spaces simulated within a conceptual office building. EDSL Tas is used to run building energy performance simulations. Effects of occupant behavior patterns on simulation outcomes are compared for five sample winter and summer workdays, with respect to heating and cooling loads. Results present findings on how diversity of occupancy profiles influences the consumption outcomes.     

Operational characteristics of residential and light-commercial air-conditioning systems in a hot and humid climate zone

Forced-air space-conditioning systems are ubiquitous in U.S. residential and light-commercial buildings, yet gaps exist in our knowledge of how they operate in real environments. This investigation strengthens the knowledge base of smaller air-conditioning systems by characterizing a variety of operational characteristics measured in 17 existing residential and light-commercial air-conditioning systems operating in the cooling mode in Austin, Texas. Some key findings include: measured airflow rates were outside of the range recommended by most manufacturers for almost every system; actual measured cooling capacities were less than two-thirds of rated cooling capacities on average; hourly fractional operation times increased approximately 6% for every °C increase in indoor–outdoor temperature difference; and lower mean indoor surrogate thermostat settings and higher supply duct leakage fractions were most associated with longer operation times. The operational characteristics and parameters detailed herein provide insight into the magnitude of the effects of HVAC systems on both energy consumption and indoor air quality (IAQ) in residential and light-commercial buildings.     

A covert field‐intervention experiment to determine how heating controls that conserve energy affect thermal comfort

A field‐intervention study was carried out in 106 households in Sweden. Without informing the householders, a retrofitted heat pump controller was twice disabled for 1 week at a time over a 4‐week period during the heating season, using a single‐blind cross‐over design with two pseudorandomly selected groups of householders, each experiencing different conditions at any given time. Thermal comfort was assessed by observing the total number of times that householders made adjustments to their set point temperature under each condition. A within‐household, repeated‐measures analysis was performed to determine whether this indicator was positively or negatively affected when the secondary controller was disabled so the heat pump system operated as designed. While over 80% of households showed no effect, among those that did respond to the imposed changes, a Wilcoxon matched‐pairs signed‐ranks test indicates that disabling the retrofitted controller had a negative effect on thermal comfort (P < 0.05 for a 2‐tail test), in that it resulted in significantly more thermostat adjustments. A concurrent increase in the variance of indoor temperature about the household mean was significant (P < 0.001) but small: The range within which indoor temperatures were maintained for 95% of the time (2.5 K) was increased by only 0.3 K (16%), indicating the sensitivity of the approach.     

Compensation for differential energy balance across a building incorporating solar energy systems

In order to compensate for imbalance in solar energy between different sides of a building, and the resultant difference in energy availability and (heating/cooling) demand, methods using offsetting were developed to adjust occupiers’ energy bills. In the case of solar electricity generation, a model was considered, in which all the power is routed through common meter(s), so that total electricity generated is recorded. Equal proportions of this metered energy can then be deducted from occupiers’ individual meter readings, to give the net energy use for which each user is billed. Computer-based models were used to calculate the imbalance on those energy demands, which are affected by solar gain, i.e., space heating and cooling. The offset was calculated, such that all users pay the same bill for a given thermostat setting, and are charged more or less, for settings which result in higher or lower energy consumption respectively. Several case studies were performed, in which one building parameter was changed between successive trials. It was found that the offset was different in each case. Therefore, it is necessary to calculate the offset separately for each location, and for each building, depending on those parameters related to solar and thermal energy exchange.     

新型数字温控器及远程控制系统

介绍了一种采用模糊控制的新型数字温控器及远程控制系统。     

植物及水体在民居中的调温作用

以浙江省安吉县任卫中所建造的夯土生态屋为例,把遮阳的含义进行了延伸与拓展,阐述了植物及水体在民居中的调温作用,说明了绿色植物与水体是隐性遮阳的重要元素.     

小型半导体恒温箱制冷性能试验研究

介绍了半导体热电制冷的研究现状。设计了小型半导体恒温箱,对其结构进行了分析,建立了小型半导体恒温箱测试系统。探讨了环境温度、热端强制对流散热、自然对流散热对热端、冷端、恒温箱内温度的影响。分析了稳定工况下,对半导体芯片施加不同电压时,冷端温度及电功率变化。环境温度越低,热端采用强制对流散热时冷端的温度越低。当处于稳定工况时,施加的电压增大到一定值后,即使电压继续增大,冷端温度的变化也不明显。应在尽可能控制耗电量的前提下,选择最佳电压。     

燃气热水器防过热防空烧的设计分析

分析了在家用燃气快速热水器的防过热、防空烧保护设计时应注意的影响因素,提出温控器的动作温度（换热器换热管的中端温度）宜设定为85—100℃。     

中控.SUPCON楼宇自控产品在医院建筑中的节能应用

本文对中控．SUPCON楼宇自控产品在医院建筑中的节能应用进行了分析和介绍,包括PCS-300分布式可编程控制系统对医院建筑机电设备节能监控管理、联网型风机盘管温控器FCU302对风机盘管集中节能管理、LCS-300智能照明控制系统对照明的节能控制。     

适合热计量的室内采暖系统

根据按户热计量采暖系统的技术要求,介绍了几种适合热计量的室内采暖方案,指出其优缺点及适用范围,分析了散热温恒温阀在热计量中的作用,并以具体实例阐述如何在双管系统中应用恒温阀解决水力失调问题。     

火墙环境下相变材料封装盒体的吸放热规律

采用恒温箱模拟火墙环境对肉豆蔻酸封装盒体进行加热与自然降温试验,通过埋置热电偶测试该封装盒体中不同位置处的温度,分析了不同金属和厚度封装盒体对其吸放热规律的影响.结果表明:肉豆蔻酸封装盒体在加热阶段可吸收并储存大量热量,在降温阶段具有明显的持续放热平台,可用于调节火墙采暖建筑物的室内温度,随着封装盒体厚度的增大,其储热能力和对周围空间的供热能力增强.当封装盒体厚度相同时,铝质肉豆蔻酸封装盒体的完全相变时间比铜和铁质肉豆蔻酸封装盒体的完全相变时间缩短了10%~20%.     

预应力混凝土箱形倒虹吸管温度应力的有限元分析

运用ANSYS有限元热—结构耦合分析建立箱形倒虹吸管结构温度计算的模型,分析了温度应力对预应力混凝土箱形倒虹吸管的影响,得出当温度应力过大时,会造成倒虹吸管表面产生裂缝的结论,该成果对类似工程温度应力分析和温控具有一定借鉴意义。     

Harmonic analysis of building thermal response applied to the optimal location of insulation within the walls

The analysis of heat transfer through building walls using Fourier transforms and the matric method are briefly reviewed. The formalism is applied to a simple one-room building. By making a few simplifying assumptions and by considering only one- or two-layer walls and roofs, the equations are kept sufficiently short to preserve the insight of the reader into the effects of a few construction features upon the building's thermal response. Such construction features, mainly the placement of insulation inside or outside the main wall mass, are extensively discussed, with an eye on their potential energy savings.The results are: (1) the placement of insulation outside the wall masonry reduces the amplitude of the internal temperature swing caused by weather conditions and by internal heat gains. If the inside temperature is left free to oscillate within a few degrees, the amplitude of the heating or cooling load is greatly reduced, allowing for substantial energy savings. However, the building is thermally sluggish and inefficient durign thermostat setbacks because of its large wall heat storage. (2) Inside placement of insulation increases the room temperature response to weather conditions and to internal heat gains. Thus, heating or cooling is needed for temperature peak-shaving. In return the building's response to a thermostat setting change is quick and the heat stored in the walls, lost during a setback, is relatively small.     

供暖系统恒温阀控制特性分析

恒温阀由恒温控制器(核心元件为感温包)与流量调节阀组成。建立恒温阀控制室内温度的数学模型,对恒温阀的控制特性进行了分析。恒温阀的控制为比例控制,其控制精度由感温包特性、流量调节阀的机械特性、供暖系统计算参数及恒温阀控制环路的滞后性决定。