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| 1) Deselect nZEB actions not to be included in the process | ||||||||||||||||||||||||||||||||||||||
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Definition of Allowed Thermal comfort ranges |
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Flexibility & Adaptability |
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Cooling Strategies |
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Plugloads and internal gains |
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BIM systems |
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Materials | |||||||||||||||||||||||||||
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Optimize Building Envelope |
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Optimize Solar Gains / Solar Control |
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Solar Thermal System |
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Storage facilities |
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Thermal Mass |
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Energy Flexibility | |||||||||||||||||||||||||||
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Improve Window to Wall Ratio |
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Improve Daylight Factor |
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Photovoltaics |
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Construction Det. |
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Energy Recov. | |||||||||||||||||||||||||||||
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Optimize Insulation |
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Energy performance Calculation |
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Mechanical Ventilation |
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Air tightness |
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Heat Pumps | |||||||||||||||||||||||||||||
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Efficient Space Design |
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Natural Ventilation |
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Domestic Hot Water |
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Activated Elem. |
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Funding | |||||||||||||||||||||||||||||
| 2) Define main drivers, targets, dates and track the status of the actions throughout the life cycle phase | ||||||||||||||||||||||||||||||||||||||
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Actions (Task Description) |
Main
driver (Lead) |
Specification
(Quantitative / Qualitative Targets) |
Start Date | Deadline | Status | |||||||||||||||||||||||||||||||||
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2,1 | Definition of Allowed Thermal comfort ranges |
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❶Description of the
Action There are six factors to take into consideration when designing for thermal comfort. Its determining factors include the following: Metabolic rate (met): The energy generated from the human body Clothing insulation (clo): The amount of thermal insulation the person is wearing Air temperature: Temperature of the air surrounding the occupant Radiant temperature: The weighted average of all the temperatures from surfaces surrounding an occupant Air velocity: Rate of air movement given distance over time Relative humidity: Percentage of water vapor in the air The environmental factors include temperature, radiant temperature, relative humidity, and air velocity. The personal factors are activity level (metabolic rate) and clothing. Looking at the operative temperature, the levels of radiation and convection are important. The following values can serve as general orientation when it comes to comfortable temperature sensation: The vertical air temperature difference between 0.1 and 1.1 meters above the floor should be less than 3K. The asymmetry of the radiation temperatures (windows or other cold surfaces against interior walls or similar) should be less than 10 K. Surface temperatures of the floor between 19 and 26 ° C are perceived as pleasant. In summer, the room temperature should not exceed 30 ° C. |
❷ Importance: Thermal comfort is very important regarding the quality of the building's indoor environment, and so one of the key aspects for the users to be guaranted. The property value is even higher when comfort ranges could be adhered. |
❸ Difficulty: - Complexity of the building services system and control could increase by strict comfort requirements, also raising the planning and maintenance costs of such comfort directed heating and cooling systems - Narrowly interpreted comfort values do not allow energy flexibility and could raise the energy consumption |
❹Standards and
Regulations: - Standard EN 15251 specifies indoor environmental input parameters faddressing indoor air quality, thermal environment, lighting and acoustics - EN 13779 applies to the design and implementation of ventilation and room conditioning in non-residential buildings - ISO Standard 7730 (ISO 1984) - Determination of the PMV and PPD Indices |
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2,2 | Optimize Building Envelope (Compactness and Insulation) |
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❶Description of the
Action The building envelope is first of all a matter of design, secondly a matter of safety for the residents. The strategy of saving energy by the building's envelope is known from the passive house standard: A compact building form and good insulation reduce the transmission losses, an airtight building envelope reduces the ventilation losses. Ideally, a simple structure is cost efficient (compact design), due to the relatively small envelope area in relation to the volume. The latter is expressed by the form factor as the ratio of enveloping area to heated volume - the smaller the form factor, the more favourable for the energy balance and construction costs of the building. Some passive house planners use the term "form factor" for the ratio of envelope area to treated floor area, so it makes sense to see what's behind the numbers. Big and compact buildings have small form factors, single family buildings big ones. |
❷ Importance: - Reduces the potential heat losses to the outside, makes comfortable wall heating systems work efficiently - A compact and well insulated building has less overheating problems - Thermal bridges caused by junctions of different building components are reduced |
❸ Difficulty: - Design variations are more restricted when thinking of compactness and insulation issues - Know-how and experience is necessary to plan and implement compact and well insulated buildings |
❹Standards and
Regulations: - passive-house standards described at http://passivehouse.com/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm - Some building codes like in Austria include limit values for the heating demand based on the form factor and so compactness of the building |
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2,3 | Improve Window to Wall Ratio |
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❶Description of the
Action For passive solar gains, the glazing and transparent components of a building should have a high total solar energy transmittance (g-value). On the other hand, the transparent parts of the building envelope create high losses (factor 5) compared to the opaque ones during cold seasons. A precise statement about which heat gains the building can use results in a simulation calculation with extensive consideration of the energetically relevant factors. Mostly a window to wall ratio of 20 to 30% can be found talking about residential buildings in European climate. That could be totally different in commercial buildings and other climate zones. Corresponding standards for insulating glass range around U-values of 0.8 - 1.3 W/m²K. Another important aspect - the energy balance of windows: A south-oriented window with a glazing U-value of 1.2 W/m²K and a g-value of 0.63 (means that 63 percent of the solar energy pass through the glass into the room) loses as much heat as it gains from the outside - the energy balance is zero. For the same window and the other orientations, the balance is negative. So generally for the south oriented windows a U-value of at least 1.2 W/m²K or lower, and for all the other windows a U-value around 0.8 W/m²K or lower is the best solution in residential buildings. |
❷ Importance: One gets energy savings only by considering the optimal window to wall ratio and at the same time thinking of an optimal g- and U-value of the walls and windows. These energy savings are related to both the energy balance during summer and winter. |
❸ Difficulty: - Again design variations are more restricted - A lot of know-how to follow all regulations and legal codes set on windows, doors, walls and buildings generally is necessary when planning an optimal window to wall ratio |
❹Standards and
Regulations: There are mainly minimum requirements in different national building codes regarding the ratio of window to net-floor area like in the Austrian national building guidelines "OIB Richtlinie 3" (2015) - page 6/7. These minimum requirements mostly refer to daylight or natural ventilation standards. Only the ASHRAE 90.1 - 2007 standard defines requirements for WWR. |
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2,4 | Optimize Insulation |
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❶Description of the
Action The heat transmission losses through external building components are in the focus of an energy-efficient design. The so-called envelope surface A separates the heated inner volume of the building from the outside space, from unheated building parts or from the soil. It covers both the transparent and the opaque areas of a facade, roof, etc. The heat transmission trough an external component is described by its U-value and indicates the potential heat that conducts through the area of 1 m² at 1 Kelvin [K] temperature difference between the out- and inside. The U-value of an external component, multiplied by the area of the component and the temperature difference between inside and outside, gives the potential heat flow to the outside. Insulating materials have a low thermal conductivity λ and considerably reduce the component thickness as well as the U-value. That is the reason why they are currently used for upgrading the building envelopes when speaking about energy eficiency. For example pressed straw as insulation material has a thermal conductivity λ of 0.055 W/mK and requires a thickness of 41 cm to achieve a passive house-compatible U-value. Vacuum insulated panels (VIPs) with λ around 0.002 W/mK reach the same U-value with a layer of 1.5 cm. The comparison of U-values and the subsequent choice of the construction are decisive criteria for the creation of energy-efficient buildings and thus also for a sustainable architecture. |
❷ Importance: Insulation measures raise the indoor comfort. The decision on the construction and the insulation materials for the external building components is crucial in a very early planning stage - it has a very high influence on: - the decision of the heating system incl. the energy sources and heat dissipation - the energy consumption during operation |
❸ Difficulty: - Knowledge on appropriate constructions is necessary to avoid thermal bridges and all related challenges, to apply airtight junctions and durable insulation etc. - Insulation investments currently have a long payback time due to low energy costs - In some cases insulation measures fail because of lacking space to the adjacent plot |
❹Standards and
Regulations: - National building codes stipulate limit values for specific building components. - Indirectly a lot of voluntary green building rating systems like LEED support low U-values by setting energy demand targets. Papers and Regulations: http://ec.europa.eu/environment/gpp/pdf/thermal_insulation_GPP_product_sheet.pdf, https://www.eurima.org/regulatory/eu-legislation/directives.html |
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2,5 | Efficient Space Design |
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❶Description of the
Action The purpose of an efficient space design is to identify those aspects that contribute to reach the highest functionality from a given space. The key aspects are the reduction of exceeding space (e.g. rethinking of a basement), the definition of the space/building function, the design of a balanced proportion between the used area and the built area, the definition of the use of the spaces according to the context, the orientation and the Window to Wall Ratio of the envelope. |
❷ Importance: - An efficient space design can lead to lower building and maintenance costs - Positive effects on working (or studying) enviroment in non-residential buildings - High energy saving potential exploiting the boundaries: orientation to maximise the solar gains during winter and to minimise them during summer |
❸ Difficulty: Building function can vary during the life-span. Space efficiency does not generally have high priority on the agenda in most building projects. |
❹Standards and
Regulations: There are no standards or regulation on this matter. |
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2,6 | Flexibility & Adaptability |
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❶Description of the
Action The concept of flexibility & adaptability refers to the possibility to make changes quickly and with relatively little effort or cost. In public buildings, adaptability can be associated, for example, with major changes in occupancy, usage or services. Flexibility is related to the configuration of working areas. |
❷ Importance: Changes in the configuration can be done without having strong consequences on comfort and technical systems' efficiency. |
❸ Difficulty: Major challenges arise during the planning phase. A bigger effort is required. |
❹Standards and
Regulations: No standards or regulations are available. |
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2,7 | Optimize Solar Gains / Solar Control |
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❶Description of the
Action To take advantage of solar energy passively in the design of structures many criteria, such as e.g. the orientation of the building, the proportion of glass in the façade and the materiality of the building are playing a role. The size and the positioning, but especially the orientation of the window surfaces are particularly important for passive solar energy use. Another criterion that must be taken into account when optimizing heat gains is the summer heat protection. Particular attention must be paid for the heating season, especially for non-residential buildings. Summer loads and cooling requirements of the building must also be considered. Basically, it should be remembered that the sun occurs at steeper and shallower angles, depending on the season, and thus permeates more or less deep into the building. Also variable is the duration of sunshine and the radiation intensity, which is also influenced by the clouds. |
❷ Importance: Optimally used passive solar systems can reduce the heating and cooling demand by 30 to 50%. |
❸ Difficulty: Specific knowlegde is necessary to create a good balance between passive heating and cooling measures over the year. |
❹Standards and
Regulations: The passive-house standards described at http://passivehouse.com/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm will give a lot of hints for the topic. |
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2,8 | Improve Daylight Factor |
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❶Description of the
Action Daylight Natural light is available depending on weather, day and season in quite different illuminance levels and fluctuates between 5,000 lux in winter up to 20,000 lux in summer. Daylight visually has the advantage that it contains all the spectral colors compared to artificial light. The change in light intensity and light color gives people a sense of the time of the day and the season, as well as continuous subconscious information about the outside climate. It stimulates the human metabolism, the formation of vitamins and the hormonal balance, as well as stimulates the soul through beautiful impressions such as a sunset, a rainbow or a stormy sky. The Daylight Factor is a ratio that represents the amount of illumination available indoors, relative to the illumination present outdoors at the same time under overcast sky. Sun protection systems determine the appearance of buildings and give architects extensive and differentiated freedom of design. The market today offers a multitude of shading elements and concept variants that range from classic systems such as sunblinds, roof projections and blinds to products such as electrochromic and thermochromic glass or holographic optical elements. |
❷ Importance: - Daylight significantly improves our health and wellbeing, makes us more productive and has a positive impact on the environment and business costs. - In terms of sustainable planning, daylight has a clear advantage compared to artificial light. But at least in office buildings the articicial lighting has to be adjusted to the indoor daylight conditions properly to exploit the expected savings. |
❸ Difficulty: - Daylight deprivation in buildings has been shown to have hugely damaging consequences. - Artificial light requires electrical energy and the heat input with bulbs is significantly higher than with daylight. - Prediction of illumination, planning knowledge |
❹Standards and
Regulations: - Building Code (or Building Regulation) requirements associated with ensuring adequate daylight have been introduced - ISO 8995:2002 Lighting of indoor work places - EN 12464-1:2002 Light and lighting – Lighting of work places – Part 1: Indoor work - BS 8206-2 Lighting for buildings. Part 2: code of practice for daylighting |
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2,9 | Energy performance Calculation |
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❶Description of the
Action Energy performance calculation of the building is conducted, thanks to a calculation tool or simulation, during the planning phase to estimate the annual energy demand for space heating, cooling, electricity and domestic hot water. The main features of the calculation method are provided by the European technical standard ISO 13790:2008 that includes: - the heat losses by transmission and ventilation of the building when heated or cooled to constant internal temperature; - the contribution of internal and solar heat gains to the building heat balance; - the annual energy demand for heating and cooling to maintain the specified set-point temperatures in the building – latent heat not included. Nevertheless, each country identified its own specificities in the calculation, defining specific boundaries, targets and energy performance classes tailored to the national context (See D2.1 Report on National Implementation of nZEBs). |
❷ Importance: An accurate energy performance calculation in the planning phase can lead to the adoption of the best design choices, from the energy efficiency point of view. Moreover, a positive impact on the real estate market has been recorded in countries with a long tradition of EPC. |
❸ Difficulty: - Special knowledge is needed to calculate the energy performance - The values from calculation can vary in a big range due to user influence and quality of the implemented construction and building services system |
❹Standards and
Regulations: ISO 13790:2008: Energy performance of buildings - Calculation of energy use for space heating and cooling. Energy Performance in Buildings Directive (EPBD 2010) and actual amendments (2016). |
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2,1 | Natural Ventilation |
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❶Description of the
Action Natural ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces. This natural ventilation of buildings depends on climate, building design and human behaviour. There are basically two types of natural ventilation that can be employed in a building: wind driven ventilation and stack ventilation. Both of which are caused by naturally occurring pressure differences. However, the pressure differences that cause wind driven ventilation uses the natural forces of the wind where as stack ventilation is caused by pressures generated by buoyancy as a result in the differences in temperature and humidity. Hence, there are different strategies in the optimization of the two types of natural ventilation. Factors directly influencing the airflow through openings: - Wind speed and pressure - Buoyancy (stack) pressure (interior temperature and humidity differences) - Characteristics of openings ("effectiveness") - Effective area of multiple openings Indoor Environmet Considerations/Requirements: - Thermal Comfort - Indoor Air Quality |
❷ Importance: - Natural ventilation can support mechanical ventilation systems to increase the indoor air quality and to cool the building by night and free cooling - It helps saving operating costs of the mechanical ventilation system by offering better indoor air quality |
❸ Difficulty: - Only in few cases natural ventilation is sufficient for establishing high indoor air qualiy - It is very difficult to plan and calculate sufficiently dimensioned natural ventilation systems, because it is dependent on so many parameters |
❹Standards and
Regulations: - ASHRAE Standard 55 or ISO 7730 (thermal comfort) - ASHRAE 62.1 and 62.2 or EN15242 / EN 13779 (ventilation rates, contaminant levels) - New standardization projects for natural ventilation started in 2017 in the groups CEN/TC 156 (Ventilation for buildings) and ISO/TC 205 (Building design) |
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2,11 | Cooling Strategies |
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❶Description of the
Action The main heat flows into a building are: - conduction through the building envelope - ventilation (windows, doors) - unintended infiltration (leakages) - solar heat gains through transparent components (windows) - internal heat generation (persons, appliances) Preventing these heat gains means preventing from overheating. Cooling is necessary if the heat gains within the building significantly exceed the heat losses. To avoid overheating and hold thermal comfort passive and active cooling measures can be taken. Passive Cooling: - Natural ventilation (free / night ventilation) - Activation of thermal mass - Evaporative Cooling - Others (shading, reflective surfaces, insulation, green roofs) Active Cooling: - Open or closed loop water-to-air heat exchanger - Mechanical, or forced ventilation, driven by fans - Use of chilled water or refrigerants - Evaporative cooling and Ice storage |
❷ Importance: - Building design with integrated passive cooling measures prevents buildings from bad summer comfort and eventual costs. - In European climate it is normally not necessary to apply active cooling, except specific functionality of the building requires cooling. |
❸ Difficulty: - The lack of experienced planners and architects is a challenge when integrating passive cooling into design - Similar to natural ventilation it is not simple to calculate the right cooling demand or hours with temperatures outside the comfort band. |
❹Standards and
Regulations: - ASHRAE Standard 62.1, Ventilation for Acceptable Indoor Air Quality - EN ISO 52016-1: 2018 02 01 - ISO 52016-1:2017: Specifies calculation methods for the assessment of e.g. the sensible heating and cooling load, based on hourly calculations - EN 15251:2007 and Austrian standard B 8180 - 3 |
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2,12 | Renewable Energy - Solar Thermal Systems |
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❶Description of the
Action The use of solar thermal systems for domestic water and heating support is a simple and effective way of renewable heat generation. The system technology is at a very high level of development - the need for maintenance and the susceptibility to malfunction are low. Two different solar thermal collector systems are used: the flat collector with absorber and transparent cover as a low-cost solution and the vacuum tube collector where the absorber is evacuated in a (vacuum) glass tube to reduce heat losses. For high-temperature requirements (industrial and commercial) and with limited space on buildings, the latter can be an advantage. For meteorological reasons, a big solar thermal collector area including big buffer storage tank would be needed to cover the whole heat consumption during the European heating season. Depending on the size of the system and the energy-efficiency standard of the building, around 70% of the heating demand for domestic hot water and around 10 to 50% for the space heating can be achieved. It is important to think of how to use a possible solar surplus during the summer months in the planning phase. It is advisible to store the solar thermal heat in the heating storage tank. The domestic hot water preparation could be done by a fresh water supply system using the heat of the storage tank via an external heat exchanger. In this case, a combination with the space heating can be made relatively easy. |
❷ Importance: - Supports the heating system in replacing fossil fuels by renewable heat decentrally. - Solar thermal systems work with a relatively high efficiency in relation to PV, and run with low costs. |
❸ Difficulty: - The investments costs are high related to other heating systems because of storage tank and backup heating system. - Even if the effectiveness of solar thermal sytems is higher than the one of PV - electricity can be used for more than "only" heating and so PV is more popular installed. |
❹Standards and
Regulations: - ISO 9806:2017(en): Solar energy - Solar thermal collectors - Test methods, and many more ISO standards under the direct responsibility of ISO/TC 180 - EN 12975: Thermal solar systems and components - Solar collectors - The IEA Solar Heating & Cooling Programme offers a lot of different publications, tools and project results at https://www.iea-shc.org/ |
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2,13 | Renewable Energy - Photovoltaics |
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❶Description of the
Action Photovoltaic solar panels, each comprising a number of solar cells, transform direct and diffused sunlight into electrical energy or "solar power". For solar power generation either grid-connected systems that are designed for a moderate year-round operation or island solutions, whose dimensioning is based on assumption of peak load and battery storage, are used: Solitary operation: If there is no grid connection, memory components are required for an independent operation. This makes economic sense if the installation of a grid connection would cost more than the PV installation, e.g. in the case of parking ticket or cigarette machines, display panels, congestion sensors or agricultural applications such as electric fences, irrigations, etc. The operation of larger units as buildings with an electrical consumption around 4,000 kWh/a is very expensive and therefore useful only in special cases such as alpine huts. Grid-connected operation: In grid-parallel operation the electricity generated from photovoltaic systems passes directly - i.e. without intermediate storage via batteries - into the AC installation of the associated house. An inverter converts the DC voltage into a 230 V AC voltage and into the house installation. The solar power is consumed in the household itself or fed as surplus into the grid of the local utility. |
❷ Importance: - Supports the electric energy system in replacing fossil fuels by renewable power - especially in synergy with wind power - The investment costs of the PV modules decreased rapidly during the last years, even new business models like communal PV-plants helped to make them economical interesting |
❸ Difficulty: - In winter time, when the most electricity is consumed, PV-modules yield much less energy than during the sunny season - The PV-modules run with a relatively low efficiency related to what the solar radiation would offer per m² - ratio 1:10 |
❹Standards and
Regulations: - Publications of different standardization organisations like IEC Technical Committee TC 82: http://www.pvresources.com/en/standards/standards.php - EN 61215 - Crystalline silicon terrestrial photovoltaic (PV) modules - Design qualification and type approval (IEC 61215:2005) - Different regional regulations control the use of PV-power (e.g. issues regarding commercial law when selling power to the market). |
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2,14 | Mechanical Ventilation |
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❶Description of the
Action Sufficient ventilation is crucial for receiving high indoor air quality. In energy-efficient buildings nobody wants to have uncontrolled air infiltration by leakages in the construction. So there is a need of an airtight building envelope. The air change then has to be done by a mechanical ventilation system since the minimum hygienic air change can not be ensured solely by window, i.e. natural ventilation. The combination of low ventilation rate and thermal bridges in the construction increases the risk of mould growth. So controlled mechanical ventilation can either be done by central exhaust or central balanced (supply and exhaust) ventilation systems. The latter uses different technologies of heat recovery: Crossflow heat exchanger with heat recovery (partially also moisture recovery) or rotary heat exchanger with moisture and heat recovery. Both exhaust and balanced ventilation can also be planned as decentralized systems. A heat exchanger preheats the cold outside air by the warm air from the inside and supplies this preheated fresh air to the living rooms and bedrooms. By recovering the heat of the ventilation system the energy losses are highly reduced (up to 90% - around 150 - 200 liters of oil equivalent per household). The necessary space must be planned for the corresponding units and pipework. The decision for a ventilation system has to be made because of the comfort increase, not the energy savings. |
❷ Importance: The indoor air quality can be increased efficiently by mechanical ventilation - so the CO2-concentration in the indoor air can be held around or even below 1000 ppm. CO2 is an indicator for polluted air, so if the concentration is low, also most of the other pollutants remain at a lower level. |
❸ Difficulty: - The investment costs of a mechanical ventilation system, although "well invested money", are the most critical in almost all construction projects - at least for residential buildings, the owners often claim high costs - The running costs, including the ones for operation and filters, are also often part of critisism |
❹Standards and
Regulations: Various technical standards are known around Indoor Air Quality and ventilation system specifications (units, ducts, fire dampers etc.) like ISO 16814:2008 "Building environment design - Indoor air quality - Methods of expressing the quality of indoor air for human occupancy", standard ISO 7730, standards EN 13779 and EN 15251 |
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2,15 | Domestic Hot Water |
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❶Description of the
Action The energy demand for domestic hot water heating can reach critical values in NZEB. This is because both the built construction components and the heating systems are efficiently planned but the domestic hot water demand depends strongly on the residents - and they are hardly predictable. So there is a need for a careful planning of the domestic water supply system, e.g. if it is supplied by the overall heating system or separately by electricity or partly by renewable energy like solar thermal or heat pump etc. It is worth to think about the distribution and supply system very early. Questions like should extra pipes supply hot water storage tanks in every single flat, or should a central storage deliver heat permanently by a circulatory system or should hot water only be supplied decentralized per each flat may be clarified in the planning stage. The decision on that influences the dimensioning of the energy supply and heating system as well as space and load requirements. |
❷ Importance: - A moderate use of domestic hot water could save a lot of energy as well as money. In NZEB the energy demand for domestic hot water can reach higher values than for the heating energy demand - It is important to decide for a suitable water heating system very early in the planning stage |
❸ Difficulty: - There is a lack of knowledge and often unwillingness to install energy and water saving technologies by the professional companies regarding domestic hot water systems. - It is very hard to predict and calculate domestic hot water consumption for a specific building - detailed knowledge on the future users would be necessary. |
❹Standards and
Regulations: - DIN 1988-300:2012 and DIN 1988-3; NBN EN 806-3; EN 806 und EN 246; EN 12828: 2014 - European Technical Guidelines for the Prevention, Control and Investigation, of Infections Caused by Legionella species, June 2017 by The European Guidelines Working Group |
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2,16 | Plugloads and internal gains |
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❶Description of the
Action Internal heat gains from occupants, equipment and lighting can have a high impact on the energy demand of a building. In particular in a NZEB, where the energy demand is very low, a correct estimation of the gains can lead to a significant increase of the design effectiveness. In particular, during the design phase, it is important to classify all the potential loads: occupants, lighting, equipments and ICT devices, and to assign the correspondant gain. The gains correspond to a reduction of the heating energy demand during winter, having a positive effect on the building performance and, on the other hand, they contribute to the load to be reduced during summer. |
❷ Importance: In non-residential buildings internal gains strongly affect the heating demand in winter. In the same way these play an important role in summer. A proper estimation of their entity can lead to relevant savings in winter and avoid overheating in summer. |
❸ Difficulty: - Correct appraisal in the planning phase - Variable during the life span of a building, due to building layout or function change |
❹Standards and
Regulations: ASHRAE: Method of Test for Determining Heat Gain of Office Equipment Used in Buildings (https://www.ashrae.org/about/news/2015/new-ashrae-standard-provides-method-of-test-on-determining-heat-gain-of-office-equipment) |
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2,17 | Storage facilities |
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❶Description of the
Action The more indepent a building owner or a building complex of a community or company would like to be from specific energy sources and external energy grids the sooner investments in storage facilities will be made. They can foster both the resilience of a local energy system and the advantage to use energy sources when they are ecologically or financially interesting. In most cases they even help to become NZEB standard. Different storage technologies are available - at the moment the most cost effective ones are water storage tanks for heating and pumped-storage power plants for electricity. But electro-chemical for power, chemical storage technologies and big water storage basins with hundreds of cubic meter for heating are evolving quickly. For example in Austria, known as one of the countries with a high number of storage facilities in buildings, the most installed storage facilities are hot water and heating buffer storage tanks with a volume between 200 and 1000 liter. Electric batteries, for which the lithium-ion battery is the most common one at the moment, are currently more used to support photovoltaic systems, still less playing a role in local load management of utilities and bigger consumers. But if the problem of short resources for the batteries would be solved, they could play a more important role to help energy flexibility in energy systems. |
❷ Importance: - Storage facilities of buildings increase the flexibility and resilience of a local energy system. - Storage technologies make the efficient use of renewable energy sources possible, e.g. solar thermal technologies heat is produced during the day and consumed mostly during nighttime, the storage technologies are the missing link. |
❸ Difficulty: - Like all additional components storage technologies increase the investment costs of the building services. - The use of storage technologies increases the energy losses of the whole system. |
❹Standards and
Regulations: - REGULATION (EU) No 812/2013: energy labelling of water heaters, hot water storage tanks and packages of water heater and solar device - REGULATION (EU) No 814/2013: ecodesign requirements for water heaters and hot water storage tanks - Various standards on batteries from IEC like IEC 61960 for Li-ion, regulation on waste batteries and accumulators |
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2,18 | Construction Details - Heat Bridges |
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❶Description of the
Action Thermal bridges are localized areas in the heat-transferring envelope of a building where increased heat flow occurs. This is associated with lower inside surface temperatures. Material-related thermal bridges They occur where different materials with different thermal conductivity in the construction meet Geometry-related thermal bridges They arise when thicknesses of a building element changes or at building edges and building corners Thermal bridges due to planning and execution errors These are caused by leaks due to poorly executed construction work Advantages: Lower running costs through reduced heat loss; reduced condensation, verification of building's quality |
❷ Importance: - Avoiding thermal bridging can result in decreased energy consumption due to winter heat loss and summer heat gain - Near thermal bridges, occupants may experience thermal discomfort due to differen surface temperatures - a second impoertant reason to avoid them |
❸ Difficulty: - Due to their partly significant impact on the heat transfer, correctly modeling the thermal bridges is important to estimate overall energy use - There is a risk of condensation in the building envelope due to the cooler temperature on the interior surface at thermal bridge locations which can ultimately result in mould growth |
❸ Difficulty: - Due to their partly significant impact on the heat transfer, correctly modeling the thermal bridges is important to estimate overall energy use - There is a risk of condensation in the building envelope due to the cooler temperature on the interior surface at thermal bridge locations which can ultimately result in mould growth |
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2,19 | Air tightness |
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❶Description of the
Action The airtightness of the building envelope is an essential element in the design of energy-optimized buildings. The airtight design requires a detailed planning, in the later execution of a careful implementation and possibly a qualitative final inspection. The production of the airtightness of the building envelope already begins with the planning by means of an airtightness concept. Just as with thermal insulation, the interruptions of which by thermal bridges are avoided as far as possible, the airtightness concept ensures that the components and connection joints are airtight. For the implementation of the planning detailed drawings of the connection points are helpful. For solid inner walls, the airtightness is usually produced with the interior plaster. For multi-layered wooden structures, the airtight layer may be inside the wall. |
❷ Importance: - Airtightness of the roof and building envelope prevents damage caused by water vapour that is transported in air gaps - Ventilation systems with supply and exhaust air duly operate only if the building envelope is sufficiently airtight - Airtightness also results in better sound protection |
❸ Difficulty: - The connection joints between different materials or at construction corners and edges are problematic in planning and execution - All employees and sub-contractors need to be suitably trained / qualified to carry out airtightness of the construction - Design specifications need special attention during construction |
❹Standards and
Regulations: ISO 9972:2015 Thermal performance of buildings -- Determination of air permeability of buildings -- Fan pressurization method |
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2,2 | Thermal Activated Building Elements |
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❶Description of the
Action Thermal component activation or concrete core tempering refers to heating or cooling systems in which water-bearing pipelines pass through walls, ceilings or floors and use the thermal masses of these components for temperature regulation. Due to the considerably larger transmission surfaces compared to conventional radiators, the systems deliver significant power to the room even at low temperatures of the heating or cooling water (18° to 22°C or max. 27° to 29°C). Thus, it can be heated and cooled also with renewable energy at very low supply temperature level. |
❷ Importance: Because the power of the activated thermal mass is limited due to the small temperature difference between the heating or cooling medium and the room temperature these elements should not be clad or suspended to ensure heat exchange with the room. |
❸ Difficulty: - If the building is to be heated and cooled exclusively by means of concrete core temperature control, the architecture, building physics and technology must be optimally coordinated and the heating and cooling load consistently limited - In buildings with concrete core activation, the room temperature can not be adjusted individually or quickly |
❹Standards and
Regulations: ISO 13370:2017 Thermal performance of buildings -- Heat transfer via the ground -- Calculation methods |
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2,21 | BIM systems |
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❶Description of the
Action Building Information Modelling (BIM) refers to the optimized design and construction of buildings by means of suitable software. BIM is a smart digital building model allowing all the partners involved in a project - from architects and builders to building services and facility managers - to work together on and jointly implement this integrated model. BIM is used to draw up an intelligent digital building model that can be examined and edited collaboratively by all the partners involved. The data model digitally specifies all the relevant building data and combines and links them. The building is also geometrically represented as a virtual computer model. The BIM data are of a very high quality as they are drawn from a common data basis and are continually updated and synchronized. The immediate and continuous availability of all the current, relevant data ensures optimal information exchange between the partners and helps improve the efficiency of the planning process with regard to cost, deadlines and quality. |
❷ Importance: - Improved communication, intelligibility and visualization - Improved coordination and progress control - Improved planning and design quality - Reduction of project duration and guarantee of on-time delivery - Cost reduction (construction / operating costs) |
❸ Difficulty: - High ratio of involved stakeholders is short on experience, BIM is mainly used by architects, less structural engineering and building services engineering - Two different approaches possible -> open BIM vs. closed BIM - Varying from country to country and from manufacturer to manufacturer, same properties / parameters can have different names |
❹Standards and
Regulations: - CEN/TC 442 - Building Information Modelling (BIM) - ISO/TC 59/SC 13: Organization and digitization of information about buildings and civil engineering works, including building information modelling (BIM) - ISO 16739:2013: Industry Foundation Classes (IFC) for data sharing in the construction and facility management industries |
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2,22 | Accession of Thermal Mass |
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❶Description of the
Action Using thermal mass inside a building makes it possible to absorb and store heat energy. A lot of heat energy is required to change the temperature of high density materials like concrete, bricks and tiles. They have high thermal mass. Lightweight materials such as timber have low thermal mass. Appropriate use of thermal mass throughout homes can make a big difference to comfort. |
❷ Importance: - Thermal mass, correctly used, moderates internal temperatures by averaging out diurnal (day−night) extremes - Thermal mass must be integrated with sound passive design techniques. This means having appropriate areas of glazing facing appropriate directions with appropriate levels of shading, ventilation, insulation and thermal mass |
❸ Difficulty: - Poor use of thermal mass can exacerbate the indoor climate and can turn to energy and comfort liability. It can radiate heat all night during a summer heatwave or absorb the heat produced on a winter night - The presence of exposed mass within buildings can cause problems with high acoustic reverberation |
❹Standards and
Regulations: - ISO 13789:2017(en) Thermal performance of buildings — Transmission and ventilation heat transfer coefficients — Calculation method - ISO/DIS 52017-1(en) Energy performance of buildings — Calculation of the dynamic thermal balance in a building or building zone — Part 1: Generic calculation procedure |
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2,23 | Energy Recovery Systems |
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❶Description of the
Action Energy-recovery techniques within heating, cooling and ventilation systems can provide the right building temperature and air quality. At the same time they can reduce heat losses, and hence energy consumption. The type of system to use varies depending on the application, but the most common is heat recovery within the ventilation system. Regarding heat sources in buildings, exhaust air and the wastewater are the main used ones. Various types of heat recovery units are available for building ventilation (cross flow, rotary, twin coil, heat pipes, ...) with different efficiency. |
❷ Importance: Ventilation systems are fundamental in maintaining indoor air quality. Therefore significant energy savings can be provided by a correct design of the heat recovery within the systems. |
❸ Difficulty: The investment and running costs are higher if heat recovery is used within existing ventilation or heating systems, including more investments on filters. |
❹Standards and
Regulations: Ecodesign Directive (Directive 2009/125/EC) |
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2,24 | Heat Pumps |
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❶Description of the
Action The operating principle of a heat pump uses electric power to generate a higher temperature level out of a heat source with a lower level. This thermodynamic cycle is called the Carnot Process. Heat sources for heat pumps: - Groundwater: this is the most reliable source of heat that provides a constant heat source temperature virtually year round. The required well installation is not possible or approvable at all locations and, above all, entails high investment costs. A case-by-case examination is required. With a suitable heat distribution (e.g. underfloor heating), good performance can be achieved. - Geothermal probe: harnessing geothermal energy via a probe system is associated with higher investment costs, but is a reliable heat source depending on the location, which provides good annual work figures. Again, as with all heat pump systems, a heat distribution is necessary, which works with low flow temperatures. - Ground collector plant: a ground collector plant is very area-intensive and is only possible or useful for new construction project with sufficient land size. In the winter months, a stronger cooling of the collector must be expected, so that the work figures at the end of the heating season decrease and thus suffers the effectiveness of the heat pump system. The solution, however, is cheaper than a geothermal probe. - Heat source air: the use of an air heat pump has the advantage that no elaborate well or collector system has to be created. The main disadvantage is the poor number of jobs at low outdoor temperatures. |
❷ Importance: To reach NZEB standards, electric heat pump seems to be the most suitable technology, due to the expected increase of the renewable energy share in the national electricity mix and renewable on-site production. |
❸ Difficulty: - To run heat pumps, electricity is needed which is in many countries the most expensive and not really environment friendliest energy source at the moment - this should be taken into consideration when designing the heating system - High flow temperatures in the heat distribution system make heat pumps very inefficient |
❹Standards and
Regulations: Many standards and guidelines regulate heat pump systems. Examples: - EN 255-3: Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors - Heating mode - EN 15450: Heating systems in buildings - Design of heat pump heating systems |
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2,25 | Apply For Funding |
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❶Description of the
Action In the development of NZEB projects, not only technological and skills-related but also financial challenges could limit the implementation of interesting concepts. So there is a need to overcome these financial barriers to finalize the projects. Funding possibilities increase the probability to bring down NZEB projects. They are an important part of the portfolio the society or public organisations can give to change normal market behaviour. |
❷ Importance: - Funding is often the dot over an i for a lot of new NZEB concepts to be realized. - In Europe there are manyfold ways of possibilities for funding - it is worth to contact professional advice to benefit from this big diversity. - The process to get the funding mostly is connected to some quality assurance steps for NZEBs - could be very positive for the projects generally. |
❸ Difficulty: - The big diversity of funding schemes and possibilities confuses and makes it difficult to keep the overview, especially regarding requirements and quality assurance verification - In some cases the amount of funding bears no relation to the time and effort of application - a great barrier for little companies not having personal resources |
❹Standards and
Regulations: The European Commission as well as every nation or region has a legal framework where funding schemes are based on, because otherwise funding could be seen as a market-distorting mechanism which is not allowed. |
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2,26 | Efficient use of materials |
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❶Description of the
Action Efficient use of materials may drasticaly decrease the environmental impact, but also make savings in monetary terms. Architects may consider the geometry and layout of the building. Not only to make it more compact and space efficient (Area to Volume ratio) but also to consider how to enable a resource efficient superstructure. E.g. short spans = less material. Another example may be to set high quality requirements and tight tolerance requirements, resulting in lower usage of materials. Early in the planning phase, the environmental impact of the building materials should be calculated in order to identify potentials (LCA-calculations). |
❷ Importance: As buildings become more energy efficient, the relative impact from materials increases. In very energy efficient buildings, more than 50% of the environmental impact may be related to the use of materials. |
❸ Difficulty: It´s complex to do LCA-calculations early in the design phase. |
❹Standards and
Regulations: - ISO 129-1, EN 60300, ISO 15686 - LEED: NC-v4 MRc1: Building life-cycle impact reduction |
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2,27 | Energy Flexibility - Demand Response |
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❶Description of the
Action Energy systems based on fluctuating renewable energy sources are characterized by intermittent generation. Their rapid increase challenges the stability of both thermal and electric grids. A mitigating effect of the stress put on the grid by variable renewable energy sources (VRES) penetration can be played by buildings, which are gradually moving from standalone consumers to interconnected prosumers (both producers and consumers) able to provide and store renewable energy and actively participate in demand response. Based on the initial definition of the IEA EBC project Annex 67 (Energy Flexible Buildings), building Energy Flexibility represents “the capacity of a building to manage its demand and generation according to local climate conditions, user needs and grid requirements. Energy Flexibility of buildings will thus allow for demand side management/load control and thereby demand response based on the requirements of the surrounding grids”. In this regards, the concept if flexibility is connected to the demand response aims to reduce the peak demand in grids by adjusting the power consumption strategy of the building energy systems. This demand response is often obtained through the implementation of energy storage systems. |
❷ Importance: By utilizing energy flexibility, reduce energy from fossil sources, increase the use of renewable energy sources in the overall energy system and so reduce greenhouse gas emissions associated with new building construction. |
❸ Difficulty: A shared methodology for the evaluation of energy flexibility is still under development. |
❹Standards and
Regulations: Clean energy for all europeans. COM(2016) 860 final. Brussels, 30.11.2016. Including 2016 amended EPBD. |
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