Energy consumption of 270 schools in Tianjin,China

With the rapid development of education cause, the increasing energy consumption of school buildings is gradually causing widespread concern in recent years in China. This paper presented an analysis of energy consumption of 270 schools located in the city of Tianjin, China. The analysis focused specifically on calculating the space heating energy consumption indexes and non-heating energy consumption indexes of different types of schools, aiming at providing reliable and precise data for the government to elaborate policies and measures. The space heating energy consumption of schools adopting district heating and gas boiler were 92.04 kWh/(m²·a) and 64.25 kWh/(m²·a), respectively. Comparing to the schools without a canteen, the non-heating energy consumption index of schools with a canteen can increase by 8%–37%. Furthermore, clustering of different energy sources, the total primary energy consumption indexes were also presented. Space heating energy consumption accounted for approximately 64%–79% of the total primary energy consumption. When using time-sharing control and self-contained gas boiler instead of district heating, an amount of almost 27.8 kWh/(m²·a) and 77.5 kWh/(m²·a) can be saved respectively. Through extensive statistical analysis of the data collected, this paper demonstrated that gross floor area, heating energy source and canteen had a close relationship with the total primary energy consumption regarding complete schools. Eventually, a linear regression equation was established to make a simple prediction about the total energy consumption of existing complete schools and to estimate the energy consumption of complete schools to be built.     

Path Analysis of Energy-Saving Technology in Yangtze River Basin Based on Multi-Objective and Multi-Parameter Optimisation

The Yangtze River Basin in China is characterised by hot-and cold-humid climates in summer and winter, respectively. Thus, increased demand for heating and cooling energy according to the season, as well as poor indoor thermal comfort, are inevitable. To overcome this problem, this study focused on the influence of passive design and heating, ventilation, and air conditioning equipment performance on the energy performance of residential buildings, and explored potential energy-saving technology paths involving passive design and improved coefficient of performance through a multi-objective and multi-parameter optimisation technique. A large-scale questionnaire survey covering a typical city was first conducted to identify family lifestyle patterns regarding time spent at home, family type, air conditioner use habits, indoor thermal comfort, etc. Then, the actual heating and cooling energy consumption and information of model building were determined for this region. Subsequently, the design parameters of an individual building were simulated using Energyplus to investigate the cooling and heating energy consumption for a typical residential building with an air conditioner. The results indicated an improvement of approximately 30% in energy efficiency through optimisation of the external-wall insulation thickness and the external-window and shading performance, and through use of appropriate ventilation technology. Thus, a multi-objective and multi-parameter optimisation model was developed to achieve comprehensive optimisation of several design parameters. Experimental results showed that comprehensive optimisation could not only reduce cooling and heating energy consumption, but also improve the thermal comfort level achieved with a non-artificial cooling and heating source. Finally, three energy-saving technology paths were formulated to achieve a balance between indoor thermal comfort improvement and the target energy efficiency(20 kWh/(m2?a)). The findings of this study have implications for the future design of buildings in the Yangtze River Basin, and for modification of existing buildings for improved energy efficiency.     

Distribution and temporal variability of the solar resource at a site in south-east Norway

Globally, solar energy is expected to play a significant role in the changing face of energy economies in the near future. However, the variability of this resource has been the main barrier for solar energy development in most locations around the world. This paper investigated the distribution and variability of solar radiation using the a 10-year (2006 to 2015) data collected at Sørås meteorological station located at latitude 59° 39′ N and longitude 10° 47′E, about 93.3 m above sea level (about 30 km from Oslo), in south-eastern part of Norway. It is found that on annual basis, the total number of days with a global solar radiation of less than 1 kWh/(m²·d) is 120 days while the total number of days with an expected global solar radiation greater than 3 kWh/(m²·d) is 156 days (42.74%) per year. The potential energy output from a horizontally placed solar collector in these 156 days is approximately 75% of the estimated annual energy output. In addition, it is found that the inter-annual coefficient of variation of the global solar radiation is 4.28%, while that of diffuse radiation is 4.96%.     

Indoor temperature changes in retrofit homes

The behavioral response (e.g. changes in indoor temperatures, attention to window and door openings) to residential technical efficiency improvements (e.g. attic insulation, storm windows) is an important and largely unresolved issue. Although there is considerable discussion concerning the extent to which households take back some of the energy savings due to technical efficiency improvements in increased comfort, there is almost no empirical evidence on the subject.Detailed electricity billing data (from mid-1981 to mid-1983) were analyzed for 79 households that received financial assistance from the Bonneville Power Administration to retrofit their homes in mid-1982. The mean retrofit expenditure in these homes was $1900; the mean reduction in annual electricity use was 4700 kWh, of which 83% was due to reductions in space heating electricity use. Analysis of the electricity billing data suggests that these households increased their indoor temperature settings after retrofit by almost 1 °F on average. This temperature increase led to an estimated average loss of almost 600 kWh of electricity saving. In other words, roughly 10% of the energy saving due to retrofit was taken back in terms of increased comfort. These results concerning changes in indoor temperatures should be viewed cautiously because of limitations in the analytical method and the large variation across households.     

Investigating the feasibility of positive energy residential buildings in tropical climates

Positive energy residential buildings are houses that generate more energy from renewable sources than they consume while maintaining appropriate thermal comfort levels. However, their design, construction and operation present several critical challenges. In particular, the considerable load reductions are not always compatible with the increased level of comfort expected in modern houses. Tropical climates, meanwhile, should be more amenable to the implementation of positive energy houses for two reasons. Firstly, negligible heating is generally required as compared to colder climates, where the heating energy requirements are considerable. Then, renewable energy resources are usually abundant in tropical climates. This paper investigates the feasibility of positive energy residential buildings in the tropical island of Mauritius. A baseline model representing a typical Mauritian house is designed using DesignBuilder software. The energy efficiency of the model is then optimised by investigating a whole range of passive building design strategies, many of them adapted from vernacular architecture. Results reveal that the application of passive strategies such as shading, insulation and natural ventilation have precluded the need for artificial cooling and ventilation in the positive energy (PE) house. The resulting electricity consumption of the house decreases from 24.14 to 14.30 kWh/m²/year. A 1.2 kW photovoltaic system provides the most cost-effective solution to exceed the annual electricity requirements of the house.     

BIPV/T技术在新徽派民居中的应用探索

针对新徽派民居中存在的建筑能耗大、热舒适性差及室内空气品质低等问题,探索在保持建筑典型特点的前提下,将太阳能光伏光热建筑一体化(BIPV/T)新技术和新方法在新徽派民居中综合运用.文章主要基于作者团队最新的研究,探讨了兼顾"黛瓦"的光伏瓦技术、兼顾"粉壁"的集热?除甲醛多效墙体技术、兼顾"马头墙"的通风?除菌杀毒多效太...     

Thermal performance and environmental impact of residential buildings’ heating in Morocco

The seasonal energy requirements and fuel consumption for heating purposes in residential buildings are influenced by the architectural design, construction materials characteristics, meteorological temperature measurements, internal gains and air exchange rate of the building. The goal of this study is to assess the thermal performance and environmental impact of residential buildings’ in Morocco taking into account all these factors and considering two sources of energy: liquefied petroleum gas (LPG) and electricity. The study concludes that the heating energy requirements for the prototype building vary between 2 and 253 kWh/m².year depending on localities, glazing type, glazing area percentage, the internal gains and the air exchange rates. The electricity consumption is 2.6 times greater than that of LPG in terms of kg oil equivalent, and by using LPG instead of electricity the emissions of greenhouse gases can be 3.4 times reduced.     

Use of solar assisted geothermal heat pump and small wind turbine systems for heating agricultural and residential buildings

The main objective of the present study is twofold: (i) to analyze thermal loads of the geothermally and passively heated solar greenhouses; and (ii) to investigate wind energy utilization in greenhouse heating which is modeled as a hybrid solar assisted geothermal heat pump and a small wind turbine system which is separately installed in the Solar Energy Institute of Ege University, Izmir, Turkey. The study shows 3.13% of the total yearly electricity energy consumption of the modeled system (3568 kWh) or 12.53% of the total yearly electricity energy consumptions of secondary water pumping, brine pumping, and fan coil (892 kWh) can be met by using small wind turbine system (SWTS) theoretically. According to this result, modeled passive solar pre heating technique and combined with geothermal heat pump system (GHPS) and SWTS can be economically preferable to the conventional space heating/cooling systems used in agricultural and residential building heating applications if these buildings are installed in a region, which has a good wind resource.     

The solar heating system with seasonal storage at the Solar-Campus Jülich

The Solar-Campus Jülich is an area of 14 ha in the north of the existing University of Applied Sciences. Three independent partners are constructing low energy buildings on this site (heating demand 144 MJ m⁻² a⁻¹). To date (June 2000) an auditorium with a library has been completed as well as an additional laboratory building. The Students’ Association Aachen has erected 23 houses with accommodation for 136 students. The houses are arranged in five rows, each of them demonstrating different kinds of modern energy-saving technologies for heating and ventilation. The energy utility in Jülich intends to build industrial buildings and move their complete organisation from southern Jülich to the Solar-Campus. A solar district heating concept, with seasonal storage, is planned to cover about 50–60% of the heating demand of all the buildings. The paper gives details of the design of the pyramidal seasonal storage tank including cost analysis. The top cover of the 2500 m³ tank will be constructed of several insulated floating pontoons, which are connected to each other, so that it is possible to walk on it. The 1200 m² of collectors are distributed over the different buildings and coupled to the underground storage tank by either a 2-, 3- or 4-pipe distribution network. Due to the low energy demand, the overall energy consumption will be low (2124 GJ a⁻¹). The heating cost consequently will be high: 0.17 DM/kWh with a conventional gas-based system, and 0.54 DM/kWh with the solar system including seasonal storage.     

Energy performance of residential buildings in Singapore

Energy consumption of buildings takes up about a third of Singapore's total electricity production. In this paper, we present a pioneering study to investigate the energy performance of residential buildings. Beginning with an energy survey of households, we established the air-conditioning usage patterns and modelled residential buildings for computer simulations. An ETTV equation for residential buildings was developed. Employing this equation, we demonstrated how to achieve improved energy efficiency in residential buildings. Two types of residential buildings, namely, point block and slab block, were modelled and parametric runs performed. ETTV impacts the energy consumption of residential buildings and thus lowering the ETTV will result in reduced building heat load. Results from the developed equation showed that a unit decrease in ETTV resulted in 4% and 3.5% reduction in annual cooling energy for point block and slab block residential buildings, respectively. In addition, a set of simple energy and load estimating equations were developed using computer simulation and local climatic data. These equations provided a means of estimating the annual cooling energy consumption of residential buildings in Singapore.     

Residential energy use in one-family households with natural gas provision in a city of the Patagonian Andean region

Residential energy use was studied in one-family houses in the city of Bariloche, in the Patagonian Andean region of Argentina. A survey was conducted of households connected to the natural gas network to correlate use of gas, living area and number of inhabitants per house. The annual average consumption of gas was found to be 169 GJ, and consumption of electricity 8 GJ. This total energy use per household per year is almost double the average value reported for Stockholm, Sweden, although both locations have similar heating requirements. The difference was mainly due to heating energy consumption per unit living space, which in Bariloche was 1530 MJ/m² per year, while in Stockholm the average is around 570 MJ/m² per year. The high energy consumption in Bariloche is explained primarily by the construction characteristics of the buildings, and secondarily by the efficiency of the heating devices used. We were able to conclude that subsidies on natural gas tariffs given to the residential sector do not promote a rational use of the resource. Furthermore, almost 40% of the population (mostly households in poverty) are not connected to the subsidised gas resource, but pay prices for alternative fuels that are between 10- and 15 times higher. Policies to improve buildings and appliances would reduce emissions and make access to energy more equitable.     

不同城市住宅热湿环境及能耗的调查实测结果分析

为全面了解住宅建筑能耗情况,于2006年1月至12月分别对七大城市住宅的能耗水平进行了读数调查,并于3月、9月进行了两次关于采暖、制冷设备使用状况的问卷调查.从2006年12月开始对其中三个城市的六户住宅室内外热环境和能耗特性进行预期长达一年的详细实测.本次调查实测所得到的基础数据,能为相关部门进行能源规划和政策调整提供依据.     

严寒地区农村住宅围护结构保温改造分析

严寒地区多数农村住宅建筑围护结构热损失严重,造成其采暖能耗增加,强化建筑围护结构的保温性是提高建筑采暖效率的方式之一。以位于严寒地区的安达市某传统农宅为研究对象,采用EnergyPlus对该住宅围护结构的保温性能进行研究,并分析了建筑能耗情况,获得了建筑墙体、玻璃、屋顶等围护结构部位采用保温后的节能效率。研究结果表明：安达地区节能效率较好的墙体和屋顶保温材料为XPS保温板、玻璃窗结构形式为6mm+12mm+6mmLow-E低辐射玻璃;传统农宅采用建筑保温材料后,其节能率可达72.0%,从而降低了农村住宅采暖能耗,并可维持室内良好的热环境。     

太阳能-生物质能联合供暖系统研究

为研究太阳能-生物质能联合供暖系统的供暖效果,通过正交实验设计了多种工况,并利用TRNSYS软件对不同工况进行模拟计算得出了最优工况,按照最优工况参数进行实验研究。结果表明：在集热器面积21 m²、生物质锅炉容量10 kW、集热水箱容积1.9 m³、谷电蓄热水箱容积1 m³的工况下,联合供暖系统具有良好的热舒适性,系统平均供热效率为68.70%。     

Evaluation on energy and thermal performance for residential envelopes in hot summer and cold winter zone of China

As a result of rapid economic growth in the last several decades, energy issue is becoming more and more important in today’s world because of a possible energy shortage in the future; the usage of residential electricity has increased rapidly in China and building energy efficiency is included as one of the 10 key programs targeting energy efficiency improvement in the 11th Five-Year Plan. In response to the growing concerns about energy conservation in residential buildings and its implications for the environment, systematic evaluation on energy and thermal Performance for residential envelops (EETP) is put forward to assess the energy efficiency of envelop designs and to calculate the energy consumption of cooling and heating systems. Hot summer and cold winter zone of China was selected for EETP analysis because of its rigorous climatic and huge energy consumption. The correlations between EETPs and electricity consumptions in cooling season, heating season, and the whole year were built in Shanghai, Changsha, Shaoguan and Chengdu, which represent A, B, C and D subzone of hot summer and cold winter zone in China, respectively. Illustrations indicate that the algorithm is simple and effective, energy and thermal performance of residential envelopes can be evaluated easily. The maximum allowable values of EETPs were determined when just meeting the compulsory indices of Standard JGJ134-2001, the corresponding allowable EETPs were also gained when achieving different energy-saving degrees on basis of it. EETP method can suggest possible ways to improve the energy efficiency for envelope designs of new building and retrofits of existing buildings and provide governments some useful information for the establishment of new policy on energy efficiency buildings. It has important meanings to carry out sustainable residential building designs with high thermal comfort and low energy consumption.     

Techno-economic analysis of a hybrid energy system for CCHP and hydrogen production based on solar energy

A typical problem in Northeast China is that a large amount of surplus electricity has arisen owing to the serious photovoltaic power curtailment phenomenon. To effectively utilize the excess photovoltaic power, a hybrid energy system is proposed that uses surplus electricity to produce hydrogen in this paper. It combines solar energy, hydrogen production system, and Combined Cooling Heating and Power (CCHP) system to realize cooling, heating, power, and hydrogen generation. The system supplies energy for three public buildings in Dalian City, Liaoning Province, China, and the system configuration with the lowest unit energy cost (0.0615$/kWh) was obtained via optimization. Two comparison strategies were used to evaluate the hybrid energy system in terms of unit energy cost, annual total cost, fossil energy consumption, and carbon dioxide emissions. Subsequently, the annual total energy supply, typical daily loads, and cost of the optimized system were analyzed. In conclusion, the system is feasible for small area public buildings, and provides a solution to solve the phenomenon of photovoltaic power curtailment.     

内蒙古农牧区风力发电节能供暖技术研究

将作为内蒙古散居农牧区家庭主要能源的风力发电机的余电提供给相对分散的居住房间和牲畜棚圈、蔬菜大棚进行主要或辅助供暖,利用清洁的风能来提高建筑物、构筑物室内的舒适性,把作为建筑设备的供暖电热辐射板（或空调风机盘管）与离网型风力发电机有机结合进行工作。     

A comprehensive energy solution for households employing a micro combined cooling,heating and power generation system

In recent years, micro combined cooling, heating and power generation (mCCHP) systems have attracted much attention in the energy demand side sector. The input energy of a mCCHP system is natural gas, while the outputs include heating, cooling and electricity energy. The mCCHP system is deemed as a possible solution for households with multiple energy demands. Given this background, a mCCHP based comprehensive energy solution for households is proposed in this paper. First, the mathematical model of a home energy hub (HEH) is presented to describe the inputs, outputs, conversion and consumption process of multiple energies in households. Then, electrical loads and thermal demands are classified and modeled in detail, and the coordination and complementation between electricity and natural gas are studied. Afterwards, the concept of thermal comfort is introduced and a robust optimization model for HEH is developed considering electricity price uncertainties. Finally, a household using a mCCHP as the energy conversion device is studied. The simulation results show that the comprehensive energy solution proposed in this work can realize multiple kinds of energy supplies for households with the minimized total energy cost.     

Low-cost green building practice in China: Library of Shandong Transportation College

This paper introduces the design idea and technique utilized in the Library of Shandong Transportation College, which ranked 1st in the 2nd National Green Buildings Innovation Award in China in March 2007 due to its low cost and climate-oriented green strategy during its design and construction phase, including land saving, energy efficiency, water conservation, and so on. Originally, the place was a landfill site with an odor pool. After reconstruction, it was changed into the construction site of the library with an area of 7000m² and a scenery pond. With the integrated use of passive shading, daylighting, ventilation with atriums, high-insulation materials, underground duct ventilation, and the substitution of cooling tower with the pond water, the HVAC load design indexes are 59 W/m² and 21.8 W/m² for space cooling and heating, respectively, much lower than the newly issued Chinese energy efficient design code for public buildings. Moreover, a set of measures is utilized for water conversation, material saving, and improvement of indoor environmental quality. After three years of operation, the real effect has been validated by electricity meter and field measurement. The total initial cost for the building with the above mentioned integrated technologies was only RMB 2150 per square meter, which was worth spending in China due to the climatic adaptability and the relative low cost.