A building approaching net zero-energy use may be called a near-zero energy building or ultra-low energy house. Buildings that produce a surplus of energy during a portion of the year may be known as energy-plus buildings. If the building is located in an area that requires heating or cooling throughout parts of the year, it is easier to achieve net zero-energy consumption when the available living space is kept small.
Despite sharing the name zero energy building , there are several definitions of what ZEB means in practice, with a particular difference in usage between North America and Europe. The most cost-effective steps toward a reduction in a building's energy consumption usually occurs during the design process.
Successful zero energy building designers typically combine time tested passive solar, or natural conditioning, principles that work with the on site assets. Sunlight and solar heat, prevailing breezes, and the cool of the earth below a building, can provide daylighting and stable indoor temperatures with minimum mechanical means. Sophisticated 3D computer simulation tools are available to model how a building will perform with a range of design variables such as building orientation relative to the daily and seasonal position of the sun , window and door type and placement, overhang depth, insulation type and values of the building elements, air tightness weatherization , the efficiency of heating, cooling, lighting and other equipment, as well as local climate.
These simulations help the designers predict how the building will perform before it is built, and enable them to model the economic and financial implications on building cost benefit analysis, or even more appropriate - life cycle assessment. Zero-Energy Buildings are usually built with significant energy-saving features. The heating and cooling loads are often drastically lowered by using high-efficiency equipment, added insulation, high-efficiency windows, natural ventilation, and other techniques. These features can vary drastically between buildings in different climate zones.
Water heating loads can be lowered using water conservation fixtures, heat recovery units on waste water, and by using solar water heating, and high-efficiency water heating equipment. And miscellaneous electric loads can be lessened by choosing efficient appliances and minimizing phantom loads or standby power.
Energy Simulation in Building Design – Bóksalan
Other techniques to reach net zero dependent on climate are Earth sheltered building principles, superinsulation walls using straw-bale construction, and exterior landscaping for seasonal shading. Zero-energy buildings are often designed to make dual use of energy including white goods; for example, use refrigerator exhaust to heat domestic hot water, ventilation air and shower drain heat exchangers, office machines and computer servers, and even body heat from rooms with multiple occupants.
These buildings make use of heat energy that conventional buildings typically exhaust outside. They may use heat recovery ventilation, hot water heat recycling, combined heat and power, and absorption chiller units.
ZEBs harvest available energy to meet their electricity and heating or cooling needs. In the case of individual houses, various microgeneration technologies may be used to provide heat and electricity to the building, using solar cells or wind turbines for electricity, and biofuels or solar collectors linked to seasonal thermal stores for space heating. To cope with fluctuations in demand, zero energy buildings are frequently connected to the electricity grid, export electricity to the grid when there is a surplus, and drawing electricity when not enough electricity is being produced.
Other buildings may be fully autonomous. Energy harvesting is most often more effective in cost and resource utilization when done on a local but combined scale, for example, a group of houses, co-housing, local district, village, etc. A benefit of such localized energy harvesting note localised as opposed to individual is the elimination of electrical transmission and electricity distribution losses. These losses amount to about 7.
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The production of goods under net zero fossil energy consumption requires locations of Geothermal, Microhydro, Solar, and Wind resources to sustain the concept. Zero-energy neighborhoods, such as the BedZED development in the United Kingdom, and those that are spreading rapidly in California and China, may use distributed generation schemes. This may in some cases include district heating, community chilled water, shared wind turbines, etc. There are current plans to use ZEB technologies to build entire off-the-grid or net zero energy use cities.
One of the key areas of debate in zero energy building design is over the balance between energy conservation and the distributed point-of-use harvesting of renewable energy solar energy, and wind energy. Most zero energy homes use a combination of the two strategies. As a result of significant government subsidies for photovoltaic solar electric systems, wind turbines, etc. Entire additions of such homes have appeared in locations such as California  and other locations where photovoltaic PV subsidies are significant,  but many so called "Zero Energy Homes" still have utility bills.
This type of energy harvesting without added energy conservation may not be cost effective with the current price of electricity generated with photovoltaic equipment depending on the local price of power company electricity ,  and also requires greater embodied energy and greater resources and is thus the lesser ecological approach.. With expert design, this can be accomplished with little additional new construction cost for materials over a conventional building.
Very few industry experts have the skills or experience to fully capture benefits of the passive design. Such passive solar designs are much more cost effective than adding expensive photovoltaic panels on the roof of a conventional inefficient building. Photovoltaic generated electricity becomes more cost-effective when the overall demand for electricity is lower. The energy used in a building can vary greatly depending on the behavior of its occupants.
The acceptance of what is considered comfortable varies widely. Studies of identical homes in the United States have shown dramatic differences in energy use, with some homes using more than twice the energy of others. Wide acceptance of zero energy building technology may require more government incentives or building code regulations, the development of recognized standards, or significant increases in the cost of conventional energy. The Google photovoltaic campus, and the Microsoft kilowatt photovoltaic campus relied on U.
Federal, and especially California, subsidies and financial incentives. Led by the CEO of United Technologies and the Chairman of Lafarge, the organization has both the support of large global companies and the expertise to mobilize the corporate world and governmental support to make ZEB a reality. Their first report, a survey of key players in real estate and construction, indicates that the costs of building green are overestimated by percent.
Survey respondents estimated that greenhouse gas emissions by buildings are 19 percent of the worldwide total, in contrast to the actual value of roughly 40 percent. Those who commissioned construction of Passive Houses and Zero Energy Homes over the last three decades were essential to iterative, incremental, cutting-edge, technology innovations. Much has been learned from many significant successes, and a few expensive failures.
The zero energy building concept has been a progressive evolution from other low-energy building designs. Among these, the Canadian R and the German passive house standards have been internationally influential. Collaborative government demonstration projects, such as the superinsulated Saskatchewan House, and the International Energy Agency's Task 13 , have also played their part. The goal of green building and sustainable architecture is to use resources more efficiently and reduce a building's negative impact on the environment.
Zero energy buildings may or may not be considered "green" in all areas, such as reducing waste, using recycled building materials, etc.
- e-Technologies and Networks for Development: First International Conference, ICeND 2011, Dar-es-Salaam, Tanzania, August 3-5, 2011. Proceedings.
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The thermal patterns predicted by Energy2D roughly match those from an IR camera. There have been 29 published scientific papers that have used Energy2D as a research tool not just a citation.
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How many books have recommended it? Energy2D is a relatively new program Xie, and is not yet widely used as a building performance simulation tool. To gain more confidence in the predictions with Energy2D, an analytical validation study was therefore carried out first, inspired by the approach described in Hensen and Nakhi Loonen, Jan L. As such, this app can also be seen as an almost perfect and very customizable numerical engine for treating electrostatic problems of various assortment.
It is also very nice to see that three platforms are supported and every single one is free to use.
2 clarke j a 2011 energy simulation in building
That is just awesome and I want to say thank you for all users. I do not know how many messages of this type you are receiving. I was really impressed by how simple and easy these tools were and I'm definitely going to integrate them into some portion of my lectures. I have downloaded and demonstrating Energy2D for my heat transfer course.