Investigation of energy performance of newly built low-energy buildings in Sweden

Energy use in the built environment represents a large part of total energy use in Sweden and is one important sector where energy conservation needs to be significantly improved in order to meet the national implementation of the European goals. One key question that needs to be investigated in relation to these goals is the performance and implementation of passive or low-energy houses. This paper presents results and an evaluation of a newly built house in an area with passive houses in Linköping, Sweden. Nine passive houses were built with the aim to be energy efficient, with an annual space heating demand of 21 kWh/m², and at the same time to have the same visual appearance as any other building in the surrounding area.This study evaluates the energy performance of a residential area with low-energy buildings based on Building Energy Simulation (BES) (IDA ICE 4), and measurements from the real object. Both annual and hourly validation is performed using room by room modeling and internal heat gains. A novel approach to internal heat gain modeling is presented using time-use data (TUD). The results show possible improvements in the design, the building envelope and in the heating control.     

Bauliche Konzeptentwicklung für eine 3‐Liter‐Reihenhauszeile im Rahmen von Modernisierungsmaßnahmen in Mannheim‐Gartenstadt

Structural concept and detailing of a 3‐litre‐terraced houses on the occasion of modernization measures. Between 2001 and 2008, extensive refurbishment measures including partial renovation, complete modernisation, demolition works and subsequent new building development are scheduled for the residential area of Mannheim‐Gartenstadt. A total of 10 two‐storey residential houses built in the 1930s and the 1950s (comprising about 230 flats) are going to be refurbished. The flats are in a poor condition, not meeting nowadays standards regarding construction and technical installations. By conducting these structural measures, the GBG Mannheim housing society also follows the aim of improving the residential quarter’s attractiveness. Three buildings, including 68 flats, were to be modernised by the end of 2003. So far, refurbishment measures merely complied with the statutory requirements stipulated in the German regulations on energy conservation (EnEV), but future retrofitting measures for a terrace with 6 dwelling houses are to achieve a level of energy which will exceed these requirements by far. The energy performance of these buildings is to be substantially improved, with the aim of turning them into ’3‐litre houses’. Though this concept has been successfully implemented in new residential buildings, it is still a challenge for construction in existing buildings. Low‐energy buildings with an annual primary energy demand for heating of less than 34 kWh/m²a (inclusive of auxiliary energy) are referred to as ’3‐litre houses’. This corresponds to the primary energy content of 3 litres of heating oil.     

东北地区太阳能农宅设计和研究

针对东北地区的气候特点和农村的自然条件,根据太阳能房的工作原理,通过对农村住宅进行合理的户型设计和构造设计,有效利用太阳能解决冬季农宅采暖和夏季降温,并对太阳能产生的经济效益进行分析,通过试点工程表明,太阳能住宅设计大大提高了农宅的热工性能,既降低了冬季农宅的采暖能耗,也调节了夏季的室内温度,达到了节能、环保、经济的目的,走可持续发展的道路是可行的。     

基于太阳辐射利用的寒地建筑组团形态优化设计研究

寒地气候严酷,采暖能耗高,太阳辐射时长短。寒地建筑太阳辐射利用对降低能耗、改善室内热舒适均具有重要意义。建筑形态作为室内外环境交互界面,决定着建筑太阳辐射利用水平。研究旨在基于多目标进化算法,应用建筑信息建模、参数编程和建筑太阳辐射性能模拟工具,探索太阳辐射利用导向下的寒地建筑组团形态优化设计方法,并结合工程项目展开实践。结果表明：形态优化设计可将屋面太阳辐射可利用面积百分比于64.71%显著提高至94.15%,制冷季太阳辐射得热量于423.87kWh/m2降低至343.28kWh/m2,并将采暖季太阳辐射得热量于212.19kWh/m2提高至259.29kWh/m2;同时,形态优化设计获得了150项建筑组团形态非支配解,可助力设计者权衡采暖、制冷季太阳辐射得热量与屋面太阳辐射可利用面积百分比性能目标。     

Energy-efficient terrace houses in Sweden: Simulations and measurements

Reducing energy use in buildings is essential to decrease the environmental impact. Outside Gothenburg in Sweden, 20 terrace houses were built according to the passive house standard and completed in 2001. The goal was to show that it is possible to build passive houses in a Scandinavian climate with very low energy use and to normal costs. The houses are the result of a project including research, design, construction, monitoring and evaluation. The passive house standard means that the space heating peak load should not exceed 10 W/m² living area in order to use supply air heating. This requires low transmission and ventilation losses and the building envelope is therefore highly insulated and very airtight. A mechanical ventilation system with approximately 80% heat recovery is used. The electric resistance heating in the supply air is 900 W per living unit. Solar collectors on the roof provide 40% of the energy needed for the domestic hot water. The monitored delivered energy demand is 68 kWh/m² a. Energy simulations show that main differences between predicted and monitored energy performance concern the household electricity and the space heating demand. Total delivered energy is approximately 40% compared with normal standard in Sweden.     

加拿大卡尔加里市Okotoks小镇太阳能小区建设

简要介绍了北美目前最大的跨季太阳能储存项目——加拿大0kotoks小镇的太阳能小区建设，对其太阳能供热系统的工作原理及利用土壤床作为储能体进行大规模跨季节太阳能储存的方法进行了分析。该项目根据不同季节可利用太阳能数量的不同，分别设置了短期（临时）太阳能储箱（STTS）及跨季节太阳能储存箱（BTES），以提高太阳能的利用率。其中，BTES的效率可达50％以上。小区太阳能家用热水系统（DWH）可满足住户60％的热水需求，而太阳能采暖系统则可满足90％采暖要求；建成后每幢住宅每年可减排5t温室气体，整个小区可减排260t／年。     

Housing at Clonmel,Ireland

A 63‐house public authority scheme was chosen to monitor the energy performance of three house types: ‘standard’, ‘well insulated’ and ‘passive solar’, all essentially based on a prize‐winning house design in an EEC competition. However, inadequate space heating — since replaced —vitiated many of the expected energy savings, and in the passive solar design heat losses from the uninsulated south‐facing conservatory largely offset the solar gains. Experience also showed that some form of curtaining should be assumed when considering direct solar gain through windows. The author is a Senior Research Officer at An Foras Forbartha.     

Mitigating temperature increases in high lot density sub-tropical residential developments

Residential developments built with houses that use passive design features can have significantly reduced energy requirements for thermal comfort. In the context of global warming, this can reduce greenhouse gas emissions. The current trend towards higher lot density in residential developments and the resulting increase in thermal mass increases the associated heat island effect. Designers of future residential developments face the dual challenges of heat island impacts and any future global warming. Resource efficient house designs combined with approaches that mitigate the outdoor heat load must be considered and addressed from the design of the initial subdivision layout. Some land sub-division and house design initiatives are proposed for sub-tropical climatic conditions as prevailing in south-east Queensland, Australia. Computer simulations that account for heat island and global warming effects are used to estimate the indoor thermal performance of display houses constructed by a large scale property developer for current climate conditions and scenarios that may occur in the future. The use of north–south orientation of narrow building lots combined with high albedo house surfaces and the increased strategic use of shade trees for reducing the heat island effect of high density residential developments are presented. The cooling requirements of houses with high-energy rating (5 star or more) are found to be significantly superior to those with low rating (3.5 star) in scenarios of global warming.     

Climate change impacts on building heating and cooling energy demand in Switzerland

The potential impacts of climate change on heating and cooling energy demand were investigated by means of transient building energy simulations and hourly weather data scenarios for the Zurich–Kloten location, which is representative for the climatic situation in the Swiss Central Plateau. A multistory building with varying thermal insulation levels and internal heat gains, and a fixed window area fraction of 30% was considered. For the time horizon 2050–2100, a climatic warm reference year scenario was used that foresees a 4.4 °C rise in mean annual air temperature relative to the 1961–1990 climatological normals and is thereby roughly in line with the climate change predictions made by the Intergovernmental Panel on Climate Change (IPCC). The calculation results show a 33–44% decrease in the annual heating energy demand for Swiss residential buildings for the period 2050–2100. The annual cooling energy demand for office buildings with internal heat gains of 20–30 W/m² will increase by 223–1050% while the heating energy demand will fall by 36–58%. A shortening of the heating season by up to 53 days can be observed. The study shows that efficient solar protection and night ventilation strategies capable of keeping indoor air temperatures within an acceptable comfort range and obviating the need for cooling plant are set to become a crucial building design issue.     

Passive annual heat storage principles in earth sheltered housing,a supplementary energy saving system in residential housing

This paper looks through the many benefits of earth not only as a building element in its natural form but as a building mass, energy pack and spatial enclosure which characterized by location, unique physical terrain and climatic factors can be utilized in developing housing units that will provide the needed benefits of comfort alongside the seasons. Firstly the study identifies existing sunken earth houses in the North-west of China together with identifying the characters that formed the ideas behind the choice of going below the ground. Secondly, the study examines the pattern of heat exchange, heat gains and losses as to identify the principles that makes building in earth significant as an energy conservation system. The objective of this, is to relate the ideas of sunken earth home design with such principles as the passive annual heat storage systems (PAHS) in producing houses that will serve as units used to collect free solar heat all summer and cools passively while heating the earth around it and also keeping warm in winter by retrieving heat from the soil while utilizing the free solar heat stored throughout the summer as a year-round natural thermal resource.     

A solar heating system with annual storage

A heating system is described for a one-family house in Trento, Italy, using solar collectors with buried long-term storage water tanks, made of reinforced concrete and internally water-proofed, assisted by an electrical water—water type heat pump.

The following design parameters are described and evaluated:

a. the annual energy requirement for the house;

b. the solar energy available;

c. the average monthly efficiency of the collectors;

d. the storage tank—ground heat flows, taking storage insulation, water storage temperature and COP to be variable with time;

e. the overall energy balance of the system for the house in question.

The conclusion is that the proposed system can cover the annual energy required for this house with an electrical consumption equal to 20% of the total.     

“3‐Liter‐Haus” im Bestand – Messkonzept und Messergebnisse von 3 Heizperioden

Energetic renovation of an residential building – measurement and measuring results of an “3 liter building” during 3 heating periods. In Germany 80 % of all buildings are considered “old” from the point of view of their demand of energy. They have a considerable energy consumption and environmental impact. As object of study was taken a residential building in Ludwigshafen (Germany), which besides the usual renovation works, it was renewed paying special attention to its energy requirements. The goal of the project was to convert the building into a “3 liter building” (30 kWh/m²a). To achieve this objective the heat losses by transmission were reduced, the passive solar gains were increased and the heat losses by ventilation were decreased by installing a new ventilation system with heat recovery. In the building several variables were measured during three heating periods. The measurements showed a good correlation with the average energy requirements calculated for a big building. However some of the apartments had big deviations in respect to these average values. Now regarding the coming Energy Performance Certificate as energy requirements and energy demand certificate, the question about the influence of the behaviour of each users gains importance in buildings with few apartments. The data collected during this study show interesting results, which question the Energy Performance Certificate for buildings with few apartments.     

An arctic low-energy house as experimental setup for studies of heat dynamics of buildings

This paper addresses the difficulties in pinpointing reasons for unexpectedly high energy consumption in construction, and in low-energy houses especially. Statistical methods are applied to improve the insight into the energy performance and heat dynamics of a building based on consumption records and weather data. Dynamical methods separate influences from outdoor temperature, solar radiation, and wind on the energy consumption in the building. The studied building is a low-energy house in Sisimiut, Greenland. Weather conditions like large temperature differences between indoors and outdoors throughout long winters, strong winds, and very different circumstances regarding solar radiation compared to areas where low-energy houses are usually built, make the location very interesting for modeling and testing purposes. In 2011 new measurement equipment was installed in the house, which will be used to develop more detailed models of the heat dynamics and energy performance in relation to different meteorological variables, heating systems, and user behavior. This type of models is known as a graybox model and is been introduced in this paper.     

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.     

An active and passive solar house

The majority of the world's population lives in rural and remote areas in the Third World countries. Many of these areas still do not have regular electric and water supplies. Having the increasing cost of conventional energy in mind, a prototype solar house has been developed in which all the energy requirements of the house are met with solar energy.

Concepts of photovoltaic electric power, thermal heating and passive cooling have been used. All the systems have been functioning satisfactorily. Although the cost of this type of house will be high, such houses can bring considerable improvement in the life-style of rural and remote dwellers in Third World countries.     

新农村建设的新思维--北京平谷区玻璃台村规划设计

基于旅游产业发展的思路,北京玻璃台村在原村址上进行了原拆原建,形成了全新的农村形象;新民居的设计在农民经济承受能力的范围内,兼顾了农村生产、生活和旅游的要求,并保持了农村的特有风貌;对村前的石河进行了景观整治,与防洪巧妙结合;在新民居建设中使用了生物污水处理、外墙外保温与太阳能采暖新技术;在资金运用上将政府与农民的力量结合起来,着重于农村的产业发展和农民的创收能力的建设上.     

新疆绿色民居构造研究

通过对新疆民居特点的剖析,从屋顶种植草皮,充分利用太阳能、风能等方面,介绍了绿色民居尚需改造、提升的不同要求,指出应借鉴传统民居,充分利用气候、环境因素进行现代绿色建筑设计。     

Simulating space heating demand with respect to non-constant heat gains from household electricity

It is crucial to perform energy simulations during the building process to design a building that meets requirements regarding low energy use. In a low energy building, internal heat gains such as excess heat from household electricity are a large part of the heat balance of the building. The internal heat gains depend on the occupants and are not constant, although they are often assumed constant in simulations of space heating demand. This article analyses how different usage patterns of household electricity affects simulated space heating demand. Parametric studies of energy use-related parameters were done to study the influence from different designs. The results show that the different energy use patterns affect the space heating demand, especially in low energy buildings and during the colder parts of the year. To make accurate energy simulations of low energy buildings, household electricity use patterns should be taken into account.     

村镇住宅建设与太阳能利用

通过对我国太阳能资源分布情况的分析以及太阳能应用可行性研究,提出了一种既节约能源又节省投资的太阳能绿色建筑设计方案.将建筑设计技术与太阳能利用技术相结合,建造一种利用南外墙进行集热和蓄热的被动式太阳房或利用太阳能热水循环技术的主动式太阳房,解决严寒季节供暖问题以及生活热水供应问题,对发展村镇建设,提高人居环境质量,创建"和谐社会"有着重大的现实意义.     

Overheating in Auckland homes: testing and interventions in full-scale and simulated houses

ABSTRACT

New Zealand dwellings have thermal conditions managed with relatively light regulation. No minimum airtightness standards exist and historical increases in required insulation levels aimed to reduce winter heating energy consumption. A consequence of this policy is an increased potential for overheating in summer. There has been a steady increase in the use of heat pumps, risking heating energy savings being outweighed by cooling energy increases. Internal temperatures and humidity were monitored in the living spaces of three unoccupied, transportable houses over all four seasons of the Auckland climate. The houses are located on the same site and are of identical construction, apart from selected interventions which were tested to explore their potential to mitigate overheating. Results indicate that overheating can be extreme and long lasting. High internal temperatures are very closely connected with solar gains. Internal temperatures reached 32°C in autumn. Roof space temperatures reached 51°C in summertime. Interventions resulted in modest improvements and an airtight construction provided a small thermal benefit. A thermal model for the houses was developed using EnergyPlus and compared with actual measurements and the interventions. Early results point to the further need to reduce solar gain, increase roof-space ventilation and increase mass, where feasible.