Marta Piñeiro. Kvernhuset Report by Marta Piñeiro Lago

Kvernhuset ungdomsskole AAR4926 - Integrated Energy Design Assigment 1_ Octover 2016

Supervisor: Inger Andresen Student: Marta PiĂąeiro Lago

Abstract Kvernhuset Ungdomsskole is not and ordinary school building. It was meant to be a reference in sustainability and quality of design for educational buildings typology in Europe. As part of the Local Agenda 21 and the project for Smart and Energy efficient buildings, it was part of several experimental studies carried out by SINTEF and NTNU. It was design not only with a teaching purpose, but also as a learning tool. In this unconventional junior hight school, the students learn about energy use, recyclability, life cycles and use of resources through observation and experimentation. This junior high school is an exemplary model in natural resources use and passive strategies, which are key when designing a sustainable building in order to reduce its energy demand. For that reason, the focus point of this report, which aims to analyse the active energy systems implemented on the building, will be the use of daylight as a natural resource and its impact on the artificial lighting demand.

Index 1. 2.

Introduction ...............................................................................8 About the building......................................................................9 - Concept and goals...........................................................9 - Plan, layout and context................................................11 - The IED process.............................................................12 - The buildingâ&#x20AC;&#x2122;s envelope.................................................13

Integrated energy systems analysis..........................................14 - Daylight and lighting systems........................................14 - Ventilation system.........................................................34 - Water system................................................................36 - Heating and cooling system...........................................36

4. 5.

Results and conclusions............................................................38 Discussion.................................................................................40

1. Introduction The first time that I heard about Kvernhuset ungdomsskole was at the beginning of my first year at this master at NTNU. It was a light and lighting class and professor Barbara Szybinska Matusiak was explaining us one of her collaborations as a lighting designer. From that moment my fascination with Pir II and Kvernhuset begun.

1. Introduction _ Kvernhuset ungdomsskole

Kvernhuset is not a normal high school were students learn by listening to the teacher’s lectures. In this case the building is part of the lecture. This high school was design as a learning tool were, through its architectural design and integrated energy systems, students learn how the energy is utilised and resources are managed in a sustainable way, so they learn by experience and become more aware of the importance of a sustainable use of the natural and limited resources.

On the other hand, as part of the Agenda 21, the building was meant to be a role model for other school buildings to come. Therefore, the collaboration within different specialists from different fields was something indispensable, which makes this building the perfect example for studying the Integrated Energy Design (IED) process. The project for Kvernhuset ungdomsskole was presented at the International Architecture Exhibition at the Venice Biennale in 2000, chosen by an international jury. The theme of the exhibition was “Less Aesthetics, More Ethics”. Since then, the project of this high school in Fredrikstad has received great attention in European architectural journals. Thanks to this project Pir II Architectural was also nominated for the EU Commission’s “Mies van der Rohe Award 2003” for innovative buildings that have an artistic added value, a nomination that is by itself a big acknowledgment for the office.

Some weeks ago, when professor Inger Andresen revealed us Kvernhuset as one of her favourite sustainable buildings and asked us to choose one building to analyse, I saw the opportunity for learning more about a building which I already considered the perfect symbiosis within sustainability, creativity and aesthetics. Moreover, the advantage of having the office here in Trondheim would increase the possibilities and facilitate the process of getting first-hand information about the collaboration within different experts in the design and construction process of the building, and would give me the possibility to get in touch with an architecture office that I admire. In order to do so, the contact with the architecture office (Pir II Arkitekter), and the energy consultant (Karin Buvik) was crucial. They kindly provide me all the information I needed to carry out this small research work. Thanks to them the following findings presented in this report have been achieved.

About the building

Kvernhuset ungdomsskole was meant to be a revolutionary building regarding both the design process and the technical systems implemented at the time it was built (1998-2002). As part of the local Agenda 21 and the project “Smarte energieffektive bygninger“(Smart and Energy efficient buildings) this school is one of the firsts sustainable public buildings built in Norway. In order to create such a role model, an environmental thinking would guide the whole design process, from the initial concept to the construction, and throughout its operational lifetime. CONCEPT AND GOALS

minimizing the use of energy, materials and financial resources, with and effective and adaptable use of space. Taking into account the local climate of the region, the passive strategies would be designed in order to minimize its energy demand and create warm and cosy living spaces. Among these goals, there were also a waterborne heating system, maximum use of daylight, a nature-based water process system and the selection of materials based on their abrasion resistance, cleanliness, recyclability, minimum maintenance cost and environmentally friendly 2 . About the building _ Kvernhuset ungdomsskole

List of objectives Since the moment in which the decision of creating such an innovative building was made, a group of community members met together in order to create the committee of experts and members of the school who would guide the architects throughout the design process, as well as to elaborate a list of objectives that the proposals for the architectural competition should follow. Some of this goals were a low energy consumption in terms of space heating, ventilation and artificial lighting; technical systems based on renewable energy sources, and an environmental educational purpose. This means that all the energy related systems had to be readable, and the visibility of the environmental thinking in the building clear. It was also a prerequisite to place the school near to or in contact with natural spaces, acting accordingly to the philosophy of “building back to the site”, which means a perfect integration of the building with the surroundings with a minimum impact on the natural environment,

Fig. 1: Situation plan of Kvernhuset ungdomsskole. Pir II Arkitekter

components. On the other hand, the spatial solutions should enable flexibility, co-operation and multi-use.

2 . About the building _ Kvernhuset ungdomsskole

Pir II and Duncan Lewis & Associates proposal

The winning proposal developed by Pir II in collaboration with Duncan Lewis and Associates was clear, simple and cleverly designed. There would be three main wings in the building, each one dedicated to a different environmental educational purpose. Thus, there would be a yellow wing dedicated to the energy-related education, a blue one dedicated to the water and the green and last one dedicated to life cycles and ecology.

Moreover, a careful study of daylight conditions was carried out in order to minimize as maximum as possible artificial lighting, highlighting on the other hand this natural resource as a source of health and well-being. This proposal was also based on the utilization of local materials and elements present on the site. For instance, the blocks under the three main wings would be dug into the mountain, and emerge from it built in the same material than the rocks extracted from the digging. Besides, all the trees cut in order to construct the building would be re-utilised, either as a cladding material or as constructive elements. From the initial draft design to the final project some changes were made due to difficulties with the utilization of very new technologies. For example, the use of biomass as an energy source was finally discarded due to the difficulties on finding a pellet supplier. However, thanks to the perseverance of all the people involved in the project the global concept and main ideas remained.

Fig. 2: Concept of Kvernhuset ungdomsskole. Own elaboration.

The architectâ&#x20AC;&#x2122;s proposal took advantage of the site, using the height of the mountain for capturing the maximum amount of daylight. They used the pine trees as a filter for daylight and a natural barrier for wind, dust and sound protection, considering on the other hand the land as an energy supplier. Thereby, the use of solar and geothermal energy combined with a heat pump were proposed, a hybrid ventilation system using natural driving forces was designed, and the grey and black waters and waist would be processed on site.

Fig. 3: West faĂ§ade of Kvernhuset ungdomsskole. Pir II Arkitekter

PLAN, LAYOUT AND CONTEXT

Second floor

The school, planned for 450 to 500 students and with a gross area of 6865 m2, is located in a wooded environment in the north of Fredrikstad. The students come from surrounding residential areas by bicycle or walking, minimizing the need of private vehicles in the transportation to the site.

The layout of the building is based on the interrelation among students and the flexibility of spaces. The three main wings are located in the second floor. Each one consists of three longitudinal and well defined zones: the classrooms area, a common multi-purpose area, and the “backbone” in the middle of these two. The classrooms area is located on the north façade of every wing. It is a very flexible space and its layout can be easily changed from year to year, allowing different configurations that range from small group rooms for the students to big classes with auditorium. All these flexible solutions will make it easy to alter working environments. An open concept library connects the wings between them in a transversal way.

On the first floor, the main entrance through a glass box and a huge

1- Energy wing 2- Water wing 3- Life cycles and ecology wing 4- Library and work space

2 . About the building _ Kvernhuset ungdomsskole

The common multi-purpose area is used for noisier & dirtier researchlike activities. It is located along the south façade. It is multifunctional space where the interrelation among students occurs. Secondary students’ entrances and lockers are also located here. Between the classrooms and this general area it, can be found the “backbone” of every wing, which contains toilets, storage rooms and ventilation chutes. All the rooms with fixed installations are assembled to this “backbone”, and above this “spine” there is a transparent air duct that supplies the wings with fresh air from the ducts under the ground.

Fig. 4: Plan of the second floor of Kvernhuset ungdomsskole. Pir II Arkitekter. Own edition.

First floor

In this floor, there are located as well the technical rooms and ventilation ducts, and from north to south, located in separated rectangular areas, the arts and crafts department, the teachers’ area, administration area, the school’s kitchen and the music department.

2 . About the building _ Kvernhuset ungdomsskole

Yellow wing

Blue wing

Green wing

Fig. 6: West façade of Kvernhuset ungdomsskole. Pir II Arkitekter. Own edition.

THE EID PROCESS Due to the ambitious goals of the project, a collaboration between different experts in specific fields was required. Therefore, it makes Kevernhuset a good example for studying how the EID process works.

1- Arts and crafts department 2- Teachers area 3- Administration 4- Arts and crafts common space, hall and main entrance, canteen

5- Kitchen 6- Music department 7- Changing rooms, bathrooms and utility rooms 8- Installations and ventilation ducts

Fig. 5: Plan of the first floor of Kvernhuset ungdomsskole. Pir II Arkitekter. Own edition.

main hall is located. This big hall is the main artery of the building. It runs along the mountain that forms the back wall of the school all the way from the arts and crafts department and exhibition areas in the north end trough the cafeteria and ends in the drama-stage (which actually is a flexible, multifunctional “black box”) and outdoor café area in the south end.

Thanks to a face to face interview with one of the architects responsible for this project, Ogmund Sørli, the following first-hand information was obtained: The collaboration was easy and fruitful and no disagreements were arising during the process. The three architects responsible for the project (Mette Melandsø and Ogmund Sørli from Pir II, and Duncan

Mr. Sørli specially mentioned how useful the participation of Karin Buvik was, not only as an expert in school buildings configurations, but also due to her experience with other integrated sustainable energy systems; as well as the collaboration with Barbara Szybinska Matusiak, due to her study of the site’s daylight conditions, which allowed to optimize daylight use and minimize the need of artificial lighting.

floor, and their façades testify that the trees have been an inspiration source for design. The walls are covered with wood panelling from the plot and glass panes. Moreover, each wing has translucent panels coloured in yellow, green or blue depending on their educational purpose (yellow for the energy, blue for the water, and green for life cycles and ecology). Attached to these translucent elements there are mounted moulded “trees” in transparent coloured polycarbonate matching the colour of the panels. In addition to being decorative and identifying elements, these “trees” also feature as sun shielding. On the other hand, the trees cut from the site in order to construct the building are also re-utilised as structural columns, and wherever a tree was cut, a part of its trunk was embedded in the pavement of the school as a reminder of their previous existence. The window’s mullions were designed in wood in the original project. However, probably due to economic reasons, aluminium was finally chosen as their material, increasing their thermal conductivity.

THE BUILDING’S ENVELOPE The entire plant is composed of simple rectangular volumes, and prefabricated elements are widely used. The first floor is dug into the granite of the mountain giving a “cave” like feeling. Following the principle of utilizing local materials and elements present on the site, the stones extracted from the digging are used as gabion granite walls on the envelope of this first floor, giving thermal inertia to the building’s façades and functioning as a heat storage of the solar radiation. On top of the mountain and between the trees are located the three long and narrow main wings. The wings almost float above the ground

Fig. 7: Pictures of the stairs and the tree columns in the first floor, and the western façade of Kvernhuset ungdomsskole. Pir II Arkitekter.

2 . About the building _ Kvernhuset ungdomsskole

Lewis from Duncan Lewis & Associates) have worked in perfect synchrony regarding goals and ambitions. The teachers and other members of the school staff have actively participated during the design process and contributed with many of the ideas for the pedagogical elements present in the building. Furthermore, many people with different expertises have participated as well in the project, enriching the process and improving the final result. For instance, researchers from SINTEF, NTNU and NMBU (Norwegian University of Life Sciences) who were involved in questions related to energy demand, indoor climate conditions, rain beds and water cleaning.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

3. Integrated energy systems

In the following chapter, the various integrated energy systems present in this innovative junior high school will be explained and analysed. These energy systems take advantage of the most important renewable resources present on the site, which are daylight, fresh air, and a heat and cooling source due to energy exchange with the ground. All these integrated technical solutions were partly taken care of by a research project running parallel to the project and conducted by NTNU and SINTEF, as part of the research and development project (R&D), supported by the national programme EcoBuild. They contribute to energy saving and a better indoor climate. Therefore, it is important to consider that the better way to reduce energy demand is a good climatic design, taking into consideration the most suitable passive strategies for each climate. On the other hand, when designing an educational building, not only thermal comfort inside the building is important, but also health and well-being. Due to this fact, a special focus on the daylight design of Kvernhuset’s classroom areas will be put in this section of the report.

Comfort Percentages

SELECTED DESIGN TECHNIQUES: 1. passive solar heating

NAME: Fredrikstad LOCATION: WEEKDAYS: 00:00 - 24:00 Hrs WEEKENDS: 00:00 - 24:00 Hrs POSITION: 47.0°, 7.4° © Weather Tool

CLIMATE: Cfb Moist mid-latitude climate with mild winters. Marine climates found on the western coast of most continents. High humidity with short dry summers. Heavy precipitation in winter. Warmest month below 22°C.

Fig. 8: Fredrikstad climate table. Historical weather data. National Meteorological Station. %

MULTIPLE PASSIVE DESIGN TECHNIQUES

Before

After

Dec

Year

Comfort Percentages

SELECTED DESIGN TECHNIQUES: 1. passive solar heating 2. thermal mass effects 3. natural ventilation

NAME: Fredrikstad LOCATION: WEEKDAYS: 00:00 - 24:00 Hrs 00:00 - 24:00 Hrs 40 WEEKENDS: POSITION: 47.0°, 7.4° © Weather Tool

CLIMATE: Cfb Moist mid-latitude climate with mild winters. Marine climates found on the western coast of most continents. 20 High humidity with short dry summers. Heavy precipitation in winter. Warmest month below 22°C.

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Fig. 9: Increase in comfort percentages for Fredrikstad climate due to the use of passive solar heating. Weather tool.

DAYLIGHT AND LIGHTING SYSTEMS According to the Köppen-Geiger climate classification, Fredrikstad corresponds to a Cfb climate, which are moist mid-latitude climate with mild winters. High humidity with short dry summers, in which the warmest month is below 22°C, and heavy precipitation in winter. Characteristics that can be seen in the following table (see Fig. 8).

MULTIPLE PASSIVE DESIGN TECHNIQUES

Before

After

Dec

Year

However, as it can be appreciated in the following graph (see Fig. 9), the use of passive solar heating alone will not make a substantial difference (less than a 10% of improvement of the indoor climate

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Fig. 10: Increase of comfort percentages for Fredrikstad climate due to the combination of passive solar heating, natural ventilation and thermal mass. Weather tool.

single glass, and translucent coloured polycarbonate panels combined with low emissivity double glass windows. Since this project was built 15 years ago it is not easy to find the precise properties of the materials used. Therefore, an estimation of those will be done with the information available online.

Consequently, taking maximum advantage of the solar radiation was a crucial part of the design of this junior high school. In order to do so, a careful effort was put in the optimization of the window area (which has been calculated as a 40% of the floor area) and the choice of transparent and translucent materials that would allow a maximum uptake of solar radiation and minimal thermal losses. Materials use and properties A low compactness degree was chosen for the shape of this school, which means bigger exposed surface on the façades and the possibility to get more solar radiation inside the building. This can be translated in a healthier indoor climate for the students due to a suitable daylight factor inside the classroom area. However, this also means more thermal losses due to conductivity with the outdoor temperatures (which in cold climates like the one in Fredrikstad may be a big issue). Therefore, a special attention must be put in the selection of the isolation properties of the materials used, especially the ones used for the windows. There are three different materials used for the translucent and transparent parts of the main wings’ façades, placed gently on top of the hill, in between the existing trees. These are low emissivity double glass windows, Moniflex panels combined with a double and a

Fig. 11: Pictures of façade’s composition with translucent Moniflex panels, coloured polycarbonate panels and normal windows. J. Havran and Karin Buvik.

The standardised values for a normal low emission double glassed window does not fulfil the requirements for a passive house standard, having an U-value of approximately 1.5 W/m²K. When talking about windows, not only their thermal properties are important, but also their transmittance value (VT or Tvis), since is the value that defines the amount of light in the visible portion of the spectrum that passes through the glass. In this case, the normal transmittance value of a low emission double glass window is 0.65. The second type of translucent elements are made out of a combination of Moniflex and glass. Moniflex is an environmental friendly product produce by Isoflex and made of recycled polyethilene. The product is constructed of Crosswise glued, pleated cellulose foil with a small amount of fire retardant added. Due to its lack of content in loose

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

conditions). Nevertheless, combined with thermal mass, and natural ventilation, the improvement on the indoor temperature can be increased up to a 40% (see Fig.10). Moreover, a good daylight level indoors reduces considerably the need for artificial lighting, lowering the building’s energy consumption.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole 14

fibres it is easy to cut and handle. It is commercialised in different thicknesses that range from 10 to 60 mm, and it has an U-value of 0,0541 W/m²K, which is a very low U-value compared to a passive house standard window (0.8 W/m²K). It has in addition a single glassed pane on the outside and a double one on the inside. The transmittance in this case will be the result of multiplying the transmittance of the glass by the transmittance of the Moniflex elements, that is VTtotal = 0,33 VTMoniflex x 0,71 VTtriple glass = 0,23 (values provided by professor Barbara Szybinska Matusiak). Lastly, there is no specified U-value for the translucent coloured polycarbonate used in this building. However, using the website u-wert. net it has been possible to estimate the U-value for an hypothetical translucent partition composed of a normal low emissivity double glassed window of 24 mm with a 12mm polycarbonate layer attached to it, which has a total U-value of 1.03 W/m²K meaning a significant thermal conductivity through these part of the envelope. According to professor Barbara Szybinska Matusiak, its transmittance is guessed around 0,8, which must be multiplied per the transmittance of the two layers of glass. Therefore, the total transmittance of these components would be VTtotal = 0,8 VT polycarbonate x 0,82 VT double glass = 0,65.

of the construction materials. The windows and translucent panes of the second floor are combined with isolated panelled walls which use wood from the site, reutilising this natural resource. On the other hand, the first floor is “carved” into the rock, and the hills “reoccurs” as buildings clad with granite rubble and timber from the site, giving mass-balance to the façades composition. The roof above this first floor is made of in situ concrete, folded, and penetrated by small skylight domes. It is carried by timber posts from the site in a way that the forest re-appears inside the building. These skylights are also present on the second floor, and they have a key role on the daylight levels inside the school, especially in the classrooms, since they allow a uniform and non-disturbing daylight distribution, perfect for study environments. The curvature of their surface also plays an important role on the way the light penetrates through the domes, as well as their transmittance. These two factors will be the decisive ones in order to calculate the amount of solar radiation that is reflected and the part of it that reaches the inside of the school.

When calculating their thermal properties of the windows, the frame material must be considered as well. The linear heat transfer coefficient of an aluminium window frame is approximately 0.08 W/ mK. In order to know the U-value of this mullion, the inverse of this heat transfer coefficient has to be multiplied by the thickness of it. Therefore [(1/0.08 W/mK) x 0.05 m] = 0.625 W/m²K. The composition of the façades is made by repetition of modular elements, allowing savings in cost and time regarding the production

Fig. 12: Pictures of coloured polycarbonate panels and shading elements over the windows’ south façade, and skylight domes on top of the second floor. Karin Buvik.

As mentioned before, a good daylight design is a key factor in order to achieve energy savings. Unlike the energy demand for heating and cooling, which varies with the months and exterior climatic conditions, the energy consumption of electric lighting is usually a constant during the entire year. Therefore, energy savings in this integrated energy system may cause a significant difference in the global energy consumption. In order to analyse how efficiently the lighting system of this building has been designed, a computational analysis has been carried out. This has been done by means of modelling the less favourable main wing regarding orientation (the yellow wing) in Rhinoceros, and carrying out several simulations in the specialised software for daylight and lighting design called Diva for Rhinoceros (See Fig. 13). This wing has also been chosen due to the presence of solar cells in some of its windows on the south oriented faรงade. Thus, the objectives that these simulations aim to achieve are the followings: -To check the sufficiency of daylight levels inside the classrooms -To check possible glare exposure and the efficiency of glare control systems -To check how optimised is the position of the solar cells in this wing On the other hand, it is important to consider that some assumptions made during the modelling may affect the accuracy of the simulations. For instance, the actual luminance levels inside the wing may vary, since the surroundings of this building have been simplified in the model, meaning that the terrain has been modelled as flat and only

Fig. 13: Pictures the yellow wing model made in Rhinoceros. Own elaboration.

the neighbour volumes of the library, the near wing, and the trees have been taken into consideration in order to calculate the ambient bounces of the solar rays. Besides, the sun shielding effect of the moulded trees attached to the colour polycarbonate panels have been also omitted on the simulations due to their shape complexity. In order to make comparable analysis for the different simulations, four zones of this main wing were separately analysed, which are the common multi-purpose area facing south (1), the classroom in the corner area facing west (2), the big classroom space facing north (4) (which has been modelled without any internal divisions), and the classroom in the middle of the west class and the big class (3). These areas can be observed in the diagram bellow.

4 2

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Daylight analysis

Fig. 14: Diagram of zones analysed. Own elaboration.

15 2

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Luminance distribution The first type of simulations carried out are interior visualizations, which allow to check the interior luminance values. This photometric measure describes the amount of light that passes through, is emitted or reflected from a particular area, which means that measures the luminous intensity per unit area of light travelling in a given direction. The SI unit for luminance is candela per square metre (cd/m2). From this analysis the following visualizations were obtained.

Fig. 17: Simulation of zone 2, classroom on the west corner. Radiance visualization.

Fig. 15: Simulation of zone 1, common multi-purpose are. Radiance visualization.

Fig. 16: Simulation of zone 4, big classroom facing south. Radiance visualization.

These visualizations are carried out with Radiance through Diva simulations. When making this type of simulations is important to take into account that in order to obtain an accurate result it is necessary

Fig. 18: Simulation of zone 3, classroom in the middle. Radiance visualization.

some problems with glare. This possible glare will be checked with a specific analysis later on. These visualizations also allow us to easily visualize the luminance values. In the following colour fill images, this fact can be observed, with values that range from around 800 cd/m2 in some of the windows to 60 cd/m2 in the surfaces of the classroom. On the other hand, on these visualizations it is also possible to observe that the daylight levels inside the different zones seem to be sufficient. However, these simulations have been carried out for the specific situation of the spring and autumn Equinox, which means that this affirmation is only true for that specific moment of the year. In order to prove whether the daylight levels in the different areas are sufficient or not during the whole year, the following type of simulation has been carried out.

Fig. 19: Simulation of zone 1, common multi-purpose are, and zone 2, classroom on the west corner. Radiance visualization with colour fill.

Daylight autonomy It is widely known that performances of students increase by a good visual environment. Moreover, good quality of light plays a significant role in the psychological and biological processes of human beings.

Fig. 20: Simulation of zone 4, big classroom facing south, and zone 3, classroom in the middle. Radiance visualization with colour fill.

As it can be observed, while the zones facing north seem to have a more homogeneous distribution of the luminance levels, on the ones facing south some very bright surfaces appear, which may be translated in

However, there is certain degree of ambiguity among different studies and regulations regarding the optimal illuminance level for offices and school buildings. For instance, in the following table, the requirements for illuminance levels for different types of offices are shown (Fig. 21), which varies in a big extent from the requirements in the next table (Fig. 22), where the recommended values for different tasks carried in a classroom are detailed, not being that different the tasks that can be performed in a class than the tasks carried out in an office.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

to set a value for the ambient bounces of at least 4. This way, the simulation does not only take into account the direct daylight, but also the indirect solar radiation that results from the bounce of the solar rays with the neighbour volumes. This fact makes these simulations pretty slow, of at least one hour each, so it is important to keep a good balance between accuracy and time spent when choosing the number of ambient bounces. For that reason, 4 have been the ambient bounces defined for these simulations.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

The requirements from Fig. 21 are more similar however to the ones specified in Fig. 23, which once again refers to different working spaces and tasks.

Daylight autonomy is directly related to the Illuminance levels inside a room. Therefore, when talking about these kind of simulations it is important to understand what illuminance is. This photometric measure refers to the intensity of the light received at a surface. It is stated in lumens / meter squared (lm/m2) or lux (lx). Therefore, 1 lm/ m2 = 1 lx. Since daylight autonomy is a grid-based simulation, in order to carry these kind of analysis, a plane must be selected, in which some sensors with a specific height from the plane and distance between them will be set in order to analyse the solar radiation they receive. For the analysis of each zone of the wing, the plane of the class floor has been selected, and the height of the sensors has been specified in 0.85 m, coinciding with the height of a classroom desk. The distance specified between them is 0.5 m and the ambient bounces have been set once again to a value of 4, which is a sufficient value taking every simulation an average of 4 hours. It is also necessary to specify an occupancy schedule for the simulation, which has been set to a school schedule from 7:00 to 15:00 with daylight savings time in this case, so the target illuminance is going to be analysed whiting the hours of this schedule. Regarding this target illuminance, the minimum value required to fulfil daylight autonomy has been set as a default to 300 lx. However, as explained before, these requirements may vary and be more restrictive depending on the study or regulations.

Fig. 21: Proposed spaces uses and initial ranges for daylight criteria using DGP for glare assessment. Andrew McNeil and Galen Burrell. Building Performance Modeling Conference. 2016.

Fig. 22: Lighting in schools. Truus de Bruin-Hordijk en Ellie de Groot. Climate design/building physics, Faculty of Architecture, TU Delf.

Fig. 23: Table for recommended light level in different workspaces. NOAO (National Optical Astronomy Observatory from the U.S.)

It has been also calculated a mean Daylight Factor of 7.2% for this room. The Daylight Factor can be defined as the ratio of interior illuminance levels to exterior illuminance levels during overcast sky conditions. An occupancy based on the schedule selected previously (the school occupancy schedule from 7:00 to 15:00) also appears on the Daysim report, which has been calculated to 1680 hours per year. The Daysim report also provides additional information which is not shown in these figures. This information is the following: -Daylight Factor (DF) Analysis: 95% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across all spaces occupied for critical visual tasks, the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1.

Fig. 24: Daylight autonomy of zone 1, common multi-purpose area. Daysim simulation.

(Lux)

Average Iluminance values during daylight hours in zone 1

10000 9000 8000 7000 6000

-Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 78% for active occupant behaviour. The percentage of sensors with a DA_MAX>5% is 82%

5000 4000 3000 2000 1000 0

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190 197 204 211 218 225 232 239 246 253 260 267 274 281 288 295 302 309 316 323 330 337 344 351 358 365

-Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 69% for active occupant behaviour. The percentage of the space with a daylight autonomy larger than 50% is 96% for active occupant behaviour.

Average values for all sensors

Fig. 25: Graph of annual Illuminance levels (lux) of zone 1. Daily average values of all the sensor. Own elaboration.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

In the first simulation results (Fig. 24 and 25), which correspond to zone 1, a Daylit Area of 96% has been calculated. This means that 96% of the room area has a Daylight Autonomy that corresponds to at least 50%, meaning that 50% of the occupied time the daylight levels in the room are above the target illuminance (which was previously set to 300 lx).

for active occupant behaviour. -Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 36% for active occupant behaviour.

Moreover, a graph of the illuminance distributions during the year (Fig.25) has been elaborated with the .ill file provided by the Diva simulation. In this graph, the average dailight values for all the sensors are shown, taking into consideration only the daylit hours of the day, which have been estimated to 9 (from 7:00 to 16:00). It can be observed that these illuminance values may be very high during spring and summer months (being especially high in March and August), reaching values up to 9000 lx, which may lead to visual discomfort depending on the contrast of the surrounding. For the case of zone 2, which correspond to the classroom located on the west corner of the wing (Fig 26 and 27), the Daylit Area has been estimated to 100% of the floor area, and the mean Daylight factor has been set up to 8.6%. Regarding the rest of the Daysim report of this particular zone, it says what follows:

Fig. 26: Daylight autonomy of zone 2, classroom in the west corner. Daysim simulation.

(Lux)

Average Iluminance values during daylight hours in zone 2

10000,00 9000,00 8000,00 7000,00

-Daylight Factor (DF) Analysis: 100% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across all spaces occupied for critical visual tasks, the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1.

6000,00 5000,00 4000,00 3000,00 2000,00 1000,00 0,00

-Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 73% for active occupant behaviour. The percentage of the space with a daylight autonomy larger than 50% is 100% for active

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190 197 204 211 218 225 232 239 246 253 260 267 274 281 288 295 302 309 316 323 330 337 344 351 358 365

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

C:\Users\Marta\Desktop\Kvernhuset\kvernhuset.3dm

Average values for all sensors

Fig. 27: Graph of annual Illuminance levels (lux) of zone 2. Daily average values of all the sensor. Own elaboration.

C:\Users\Marta\Desktop\Kvernhuset\kvernhuset.3dm

-Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 81% for active occupant behaviour. The percentage of sensors with a DA_MAX>5% is 56% for active occupant behaviour. -Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 81% for active occupant behaviour. In this case, the graph elaborated of the room illuminance levels (Fig 27) shows more reasonable results, ranging from 2000 to 4500 lx during summer and spring. Anyhow, this may cause some undesirable glare, which will be analysed later on. The results of zone 3 analysis (Fig. 28 and 29), corresponding to the classroom in the middle of the big classroom and the classroom on the west corner, show a Daylit Area of 97%, and a mean Daylight Factor of 3.3%. This mean daylight factor does not fulfil the minimum value required for the mean Daylight Factor for school rooms, which is set by regulations to 5%. This fact is also warned on the Daysim report, which says the following:

Fig. 28: Daylight autonomy of zone 3, classroom in the middle. Daysim simulation. (Lux)

Average Iluminance values during daylight hours in zone 3

10000 9000 8000 7000 6000 5000 4000

-Daylight Autonomy (DA) Analysis: The mean daylight autonomy

3000 2000 1000 0

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190 197 204 211 218 225 232 239 246 253 260 267 274 281 288 295 302 309 316 323 330 337 344 351 358 365

-Daylight Factor (DF) Analysis: 51% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across all spaces occupied for critical visual tasks, the investigated lighting zone does not qualify for the LEEDNC 2.1 daylighting credit 8.1.

Average values for all sensors

Fig. 29: Graph of annual Illuminance levels (lux) of zone 3. Daily average values of all the sensor. Own elaboration.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

occupant behaviour.

C:\Users\Marta\Desktop\Kvernhuset\kvernhuset.3dm

-Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 65% for active occupant behaviour. The percentage of sensors with a DA_MAX>5% is 3% for active occupant behaviour. -Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 99% for active occupant behaviour. On the graph that represents the illuminance values for this area (Fig. 29) it can be observed that the average illuminance of this room is always bellow 1000, which means that it may require some artificial lighting to supply the lack of natural light, specially during the winter months for some tasks that requires high visual performance, since the illuminance values during these months range from 0 to 500 lx.

Fig. 30: Daylight autonomy of zone 4, big classroom facing north. Daysim simulation. (Lux)

Average Iluminance values during the daylight hours

10000 9000 8000

Lastly, in Fig. 30 and 31 can be observed the result from the last zone analysed (zone 4), corresponding to the biggest classroom of this yellow main wing, which is facing south. Despite of the fact that light coming from the south is rated as the best light for study environments, the lack of direct sunlight may be an occasional problem during the winter months, as it can be observed in the analysis results.

7000 6000 5000 4000 3000 2000 1000

For this case, the Daylit Area has been calculated as 83% of the floor area. However, the mean daylight factor is 4.7%, once again bellow 5%, which means that some artificial lighting may be needed during the daylight hours in the winter months.

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190 197 204 211 218 225 232 239 246 253 260 267 274 281 288 295 302 309 316 323 330 337 344 351 358 365

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

is 46% for active occupant behaviour. The percentage of the space with a daylight autonomy larger than 50% is 37% for active occupant behaviour.

Average values for all the sensors

Fig. 31: Graph of annual Illuminance levels (lux) of zone 4. Daily average values of all the sensor. Own elaboration.

-Daylight Factor (DF) Analysis: 88% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across all spaces occupied for critical visual tasks, the investigated lighting zone does not qualify for the LEEDNC 2.1 daylighting credit 8.1. -Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 58% for active occupant behaviour. The percentage of the space with a daylight autonomy larger than 50% is 83% for active occupant behaviour. -Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 73% for active occupant behaviour. The percentage of sensors with a DA_MAX>5% is 5% for active occupant behaviour.

Glare analysis and sun shading devices Once the sufficiency of the daylight levels has been analysed, it is also necessary to check whether it exits or not any disturbing glare due to the solar radiation. Glare can be defined as the visual sensation of discomfort caused by excessive brightness of a light source. It can be disabling or simply uncomfortable. It is subjective, and sensitivity to glare can vary widely. However, in order to make it possible to analyse glare probability, some values have been internationally set in order to identify due to luminanceâ&#x20AC;&#x2122;s contrast when glare effect may occur. Hence, some different glare levels have been established, which go from perceptible glare to intolerable glare. These different glare levels are shown in the following table (Fig. 33) and are measured according to Daylight Glare Probability (DGP). Thus, a DGP value between 0.35 and 0.40 is considered perceptible glare, which is a disturbing but tolerable glare

-Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 99% for active occupant behaviour. For this particular zone, the results of illuminance distribution are quite similar to the previous case. However, they are a litter big higher due to the fact that this room is also receiving a small percentage of light coming from the east windows during the mornings. Moreover, the number of skylights in this room is higher than in the previous one, which also ensures overhead light in the farthest area from the windows. Fig. 32: Pictures of the different shading strategies utilised in the building. On the left, moulded tree attached to the window. On the right, sunshades on the south faĂ§ade. Karin Buvik.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

The rest of the Daysim report is shown below:

effect, and above 0.45 the glare effect is considered intolerable for the human eye.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Diva considers the DGP formula as a two-part formula, based on the vertical eye illuminance that is present at the source of the camera

Fig. 33: Relation between DGP and subjective glare ratings. Wienold and Christofferson, 2006.

and the visual contrast of the scene, and It combines this two-part formula in order to calculate the daylight glare probability. With the aim of defining when shading devices to avoid glare are needed, a DGP analysis has been carried out for every of the zones defined in the module analysed. Once again, the occupancy schedule is set to a school type schedule, and the ambient bounces are set to 4. These parameters have to be set to the same values in all the simulation types in order to allow an equitable comparison. On the other hand, the fact of setting the ambient bounces to 4 makes these simulations very

Fig. 34: Graph of DGP schedule of zone 1 whit no dynamic shading. Daysim report.

time consuming, lasting each of them more than 4 hours. On Fig. 34, it can be observed the result of this analysis for zone 1, corresponding to the room facing south. As it was expectable due to the high illuminance values for this room recorded in the previous simulation, the glare analysis for zone 1 records an intolerable DGP of above 0.45 specially during the months of February, March, October and November from 9:00 to 15:00, which means that this effect is produce during the occupancy schedule. Therefore, in order to calculate the shading needed to avoid intolerable or disturbing glare, a mechanical and manually activated shading device has been modelled according to the pictures available of the school and the DGP analysis has been repeated adding dynamic shading control. These shading devices can be observed on the right picture of Fig. 32 and on the Rhinoceros model of Fig. 13. As it can be observed in the following result diagram (Fig. 35), this type of shading device does not seem to be very efficient during the winter months, which makes it necessary to design a new type of shading device.

Fig. 35: Graph of DGP schedule of zone 1 whit dynamic shading. Current shading devices. Daysim report.

that the current shading system present in the building is not able to block all this solar direct sunlight. Therefore, an alternative system composed by Venetian blinds located on the interior layer of the windows was proposed. As shown in the diagrams, this system allows to redirect all the direct sunlight without diminishing in excess the daylight inside the classroom.

The situations where unresolved glare effect was recorded were analysed. As it can be observed in the diagrams below (Fig. 36), the incidence angle of the solar radiation during November corresponds to 14 o of inclination angle, which may cause uncomfortable direct sunlight at the height of the desks (0.85 m). It can also be observed

On the other hand, as also shown in the DGP, there is no glare risk during the spring and summer months. Therefore, during these periods of the year, the Venetian blinds shading system can be completely folded, as shown in the diagrams below (Fig. 37).

Fig. 36: Diagram of the incidence angle of the solar radiation inside the classroom for the situation of November at 12:00, which corresponds to 14 o. On the upper diagram, the current shading system present in the building. On the one below, an alternative shading system composed by Venetian blinds twisted 45 o. Own elaboration.

Fig. 37: Diagram of the incidence angle of the solar radiation inside the classroom for the situation of May at 12:00, which corresponds to 46 o. On the upper diagram, the current shading system present in the building. On the one below, no shading system. Own elaboration.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

In order to do so, an analysis on the incidence angle of the solar rays inside the classroom has been carried out. This analysis has been done with the use of the Solarbeam program in order to obtain the threedimensional protractor for the city of Fredrikstad, and the website Solar Position Calculator designed by NOAA Earth System Research Lab.

Daysim Simulation Report

These Venetian blinds were modelled for two differentWarnings shading states, the first one with the slats twisted 45 o in a semi-closed position, ShadingGroup 1 has no and

Page 1 of 2

fff

the second one in a closed position with the slats twisted 70 o. This can Daysim Simulation Report be observed in the following pictures (Fig. 38). Daylit Area (DA300lux[50%])

reference sensors. ShadingGroup 2 has no reference sensors.

96% of floor area

Mean Daylight However, the factFactor of locating the 6.9% shading devices on the inside does not

Occupancy 1680may hourscause per year avoid excessive solar radiation that overheating problems 0.0% of occupied during the summer months. Due to this fact, a supplementary shading Glare hours system was located on the outside in order to avoid this problematic Shading Group 1 open 93% of occupied hours C:\DIVA\temp\kvernhusetcorridorlasttry\kvernhusetcorridorlasttry_intgain.csv effect (Fig. 38).

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Simulation Tips

Daysim generates a schedule file, that can be linked to a thermal simulation program. To open file click the link below

100% of occupied hours

Daysim SimulationShading Report Group 2 open

Page 1 of 2

With the proposed alternative of the dynamic shading system previously explained, the simulation for the DGP was repeated, as well Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 69% for active occupant behavior. The percentage of the space with a daylight autonomy l as a new Daylight Autonomy analysis. The results of this simulation is 96% for active occupant behavior. areDaylight shown below (Fig.The39 and 40).daylight autonomy is 78% for active occupant behavior. The percentage of sensors with a Continuous Autonomy (DA) Analysis: mean continuous Daylight Factor (DF) Analysis: 93% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across occupied for critical visual tasks', the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1 (see www.usgbc.org/LEED/).

Warnings

Daysim Simulation Report

Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 42% for active occupant behavior. ShadingGroup 1 has no reference sensors. 300lux Lighting Use: The predicted annual electric lighting energy use is: ShadingGroup 2 hasElectric no reference sensors.

Daylit Area (DA

Semi closed position - 45 o

Closed position - 70 o

fff

is 84% for active occupant behavior

Simulation Tips

[50%])

6.9%

Occupancy

1680 hours per year

Glare

0.0% of occupied hours

Simulation Assumptions

Daysim generates a schedule file, that can be linked to a Site Description: thermal simulation program. To open file click the link below

96% of floor area

Mean Daylight Factor

The investigated building is located in OSLO/FORNEBU_NOR (59.90 N/ 10.62 W). Shading Group 1 open 93% of occupied

C:\DIVA\temp\kvernhusetcorridorlasttry\kvernhusetcorridorlasttry_intgain.csv

User Description:

Shading Group 2 open

The total annual hours of occupancy at the work place are 1680.

hours

100% of occupied hours

Daylight Factor (DF) Analysis: 93% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across occupied for critical visual tasks', the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1 (see www.usgbc.org/LEED/). Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 69% for active occupant behavior. The percentage of the space with a daylight autonomy l is 96% for active occupant behavior. Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 78% for active occupant behavior. The percentage of sensors with a is 84% for active occupant behavior Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 42% for active occupant behavior. Electric Lighting Use: The predicted annual electric lighting energy use is:

Simulation Assumptions Site Description:

Fig. 38: Picture of the model with the exterior sunshade devices and the two stages for the dynamic shading system designed, which are Venetian blinds in a semi-closed position of 45 o and a second stage corresponding to a closed position of 70 o. Rhinoceros, Own elaboration.

The investigated building is located in OSLO/FORNEBU_NOR (59.90 N/ 10.62 W).

Fig. 39: New results for the Daylight Autonomy simulation and occupancy schedule with two dynamic The first corresponding to the Venetian blinds with the two Theshading total annual groups. hours of occupancy at the one work place are 1680. There is no electric lighting system specified for the scene. different shading states, and the second one an additional exterior sunshade. Daysim report.

User Description: Lighting Control:

ShadingControl: â&#x20AC;˘ ShadingGroup 1: The system is manually controlled according to the Lightswitch model. WARNING: Since Shading Group 1 has no reference sensor sensors are considered to be reference sensors.

Lighting Control: There is no electric lighting system specified for the scene. ShadingControl:

In the occupancy schedule graph (Fig. 39), which corresponds to the occupancy schedule previously set during the simulations (school working schedule), it can be observed in white the times of the year where the space is considered occupied and coloured black the moments of the year which are non-school period, and as it can be observed, the school is considered unoccupied during the summer months. As it can also be observed in this figure, the new Daylit Area taking into account the dynamic shading systems is 96%, and the mean DAylight Factor has been calculated as 6.9%, which are still very good values. Daysim Simulation Report This is due to the fact that the shading devices are not activated during the biggest part of the occupancy schedule, being 93% the percentage of this schedule where shading group 1 is not needed, and 100% for the case of shading group 2 (and this makes sense due to the fact that this second shading group was placed only to avoid overheating and not to deal with glare effect). These shading control schedule can be observed in Fig. 40, where the light blue colour indicates when the shading device has been manually activated.

Page 2 of 2

â&#x20AC;˘ ShadingGroup 2: The system is manually controlled according to the Lightswitch model. WARNING: Since Shading Group 2 has no reference sensor sensors are considered to be reference sensors.

file:///S:/Kvernhuset/kvernhusetcorridorlasttry%20-%20DIVA/Grid-Based/kvernhuset... 30.09.2017

The same DGP analysis was carried out for the case of zone 2. As it can be observed on the results of this simulation (Fig. 41), for this case there is also glare risk recorded. However, most of this glare risk occurs out of the occupied hours (before 7:00 or after 15:00), which means that it will be only necessary to deal with the DGP for the months of January, February, October and November, in the time zone from 14:00 to 15:00. In order to do that, and since the building does not count with a shading system in this part of the building, the same alternative dynamic shading system than in the previous case has been adopted. Although

Fig. 40: New results for the DGP and shading control schedules for the two dynamic shading groups. The first one corresponding to the Venetian blinds with the two different shading states, Daysim header File: C:\DIVA\temp\kvernhusetcorridorlasttry\kvernhusetcorridorlasttry.hea and the second one an additional exterior sunshade. Daysim report.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

â&#x20AC;˘ ShadingGroup 1: The system is manually controlled according to the Lightswitch model. WARNING: Since Shading Group 1 has no reference sensor sensors are considered to be reference sensors.

Shading Group 1 open

99% of occupied hours

Daylight Factor (DF) Analysis: 100% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across 'all spaces occupied for critical visual tasks', the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1 (see www.usgbc.org/LEED/). Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 71% for active occupant behavior. The percentage of the space with a daylight autonomy larger than 50% is 100% for active occupant behavior. Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 80% for active occupant behavior. The percentage of sensors with a DA_MAX > 5% is 43% for active occupant behavior Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 86% for active occupant behavior. Electric Lighting Use: The predicted annual electric lighting energy use is:

Simulation Assumptions Site Description: The investigated building is located in OSLO/FORNEBU_NOR (59.90 N/ 10.62 W).

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

User Description:

Since this time zone where the additional shading is needed is quite The total annual hours of occupancy at the work place are 1680. small, some curtains that allow to be moved through the façade to wherever they are needed could be a good option to solved that problem. However, as said before, this time zone is very small, so it might also be solved with a change of distribution of the students in the classroom. fff

Warnings ShadingGroup 1 has no reference sensors.

Fig. 41: Graph of DGP schedule of zone 2 whit no dynamic shading. Daysim report.

Simulation Tips

Daysim Simulation Report

Daylit Area (DA300lux[50%])

100% of floor area

Mean Daylight Factor

8.9%

Lighting Control: Daysim generates a schedule file, that can be linked to a is no electric lighting system specified for the scene. thermal simulation program.There To open file click the link below

this time the sunshade has not being use, since the orientation of this room is mainly towards west. Therefore, the overheating risk due to direct solar radiation is smaller.

Occupancy

1680 hours per year

Glare

0.7% of occupied hours

ShadingControl: C:\DIVA\temp\kvernhusetclasscorner\kvernhusetclasscorner_intgain.csv

Shading open according to the 99% of occupied hours Since Shading Group 1 has no reference sensors specified, all • ShadingGroup 1: The system isGroup manually1controlled Lightswitch model. WARNING: sensors are considered to be reference sensors. Daylight Factor (DF) Analysis: 100% of all illuminance sensors have a daylight factor of 2% or higher. Assuming that the sensors are evenly distributed across 'all spaces occupied for critical visual tasks', the investigated lighting zone should qualify for the LEED-NC 2.1 daylighting credit 8.1 (see www.usgbc.org/LEED/).

One the new DGP was calculated, it was also necessary to recalculate the Daylight Autonomy for this zone, since it may vary due to the installation of shading devices. The results of this simulation can be seen in the next figures (Fig. 41), where the new value for the Daylit Area has been calculated to a 100%. This result is quite surprising though, since it was to be expected that the introduction of this additional shading system may diminished the Daylit Are. However, when looking at the percentage the shading device is not used, this is established as 99% of the occupied hours, which may be the reason for that.

Daylight Autonomy (DA) Analysis: The mean daylight autonomy is 71% for active occupant behavior. The percentage of the space with a daylight autonomy larger than 50% is 100% for active occupant behavior. Continuous Daylight Autonomy (DA) Analysis: The mean continuous daylight autonomy is 80% for active occupant behavior. The percentage of sensors with a DA_MAX > 5% is 43% for active occupant behavior Useful Daylight Illuminance (UDI): The percentage of the space with a UDI<100-2000lux larger than 50% is 86% for active occupant behavior. Electric Lighting Use: The predicted annual electric lighting energy use is:

Simulation Assumptions Site Description: The investigated building is located in OSLO/FORNEBU_NOR (59.90 N/ 10.62 W). User Description: The total annual hours of occupancy at the work place are 1680.

The shading control schedule can be also seen in this figure, where it can be observed that this shading device is mainly required out of the occupied hours. On the graph below, which shows the new DGP schedule, it can be observed that there is still some intolerable DGP Fig. 41: New results for the Daylight Autonomy analysis, DGP analysis, and shading control recorded in the last hour of the occupancy schedule, which means schedules for the dynamic shading group corresponding to Venetian blinds with the two that and additional shading system should be implemented. Daysim header File: C:\DIVA\temp\kvernhusetclasscorner\kvernhusetclasscorner.hea different shading states. Daysim report. Lighting Control:

There is no electric lighting system specified for the scene.

ShadingControl:

• ShadingGroup 1: The system is manually controlled according to the Lightswitch model. WARNING: Since Shading Group 1 has no reference sensors specified, all sensors are considered to be reference sensors.

colliding with the different surfaces can be appreciated, as well as a simulation of the radiation that the solar cells obtained through the whole year.

This is due to the fact that both of them are receiving mainly both overhead light and light coming from the north faรงade, which is mainly diffuse light. With this kind of daylighting system where the solar radiation is not direct, the glare effect rarely occurs. Therefore, no additional dynamic shading controls are needed. The results of these simulations can be observed in the table below (Fig. 42).

The two visualizations obtained from this analysis are shown forward.

Fig. 43: South faรงade radiation map of the volume analysed, which corresponds to the yellow wing. Radiation values in KWh/m2 are displayed. Radiance. Fig. 42: Graph of DGP schedule of zone 2 whit no dynamic shading. Daysim report.

Radiation on the solar cells As means of demonstration experiment, solar cells are installed in some of the windows of the south oriented faรงade of the volume, which may be squared mono-crystalline cells. The last analysis done with Diva aims to find out whether the location of the solar cells installed on the south faรงade of this wing is optimal or not. In order to do that, two different visualizations of the exterior volume of the wing were simulated, in which the amount of energy due to solar radiation

Fig. 44: South faรงade luminance map of the volume analysed, which corresponds to the yellow wing. Radiation values in cd/m2 are displayed. Radiance.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Lastly, the same DGP simulation was carried out for zones 3 and 4. As it was expected due to the results obtained in the previous simulations, there is no glare risk recorded for these two areas.

(KWh/m2)

Annual average radiation received by the solar cells

600

500

400

300

200

100

1 9 17 25 33 41 49 57 65 73 81 89 97 105 113 121 129 137 145 153 161 169 177 185 193 201 209 217 225 233 241 249 257 265 273 281 289 297 305 313 321 329 337 345 353 361

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

The first one (Fig. 43) is a radiation map of the volume, in which the KWh/m2 that each of the surfaces receive for a specific time of the year (which has been set to the equinox at 12:00) are displayed. The

Average values all sensors

Fig. 44: Picture of the location of the solar cells on the south faรงade of the volume analysed (Rhinoceros), and graph of the average solar radiation received by the sensors during the whole year.. Own elaboration.

maximum values obtained in this simulations are located, precisely, were the solar cells are located, and the resulted values of the energy received due to the solar radiation for this area range from 1100 and 1300 KWh/m2. A similar result was obtained in the second one (Fig. 44), were the luminance map obtained shows the maximum luminance values located as well in this area of the south faรงade (which makes sense, since luminance or brightness of the surfaces also depends on the amount of solar radiation they receive, as well as in the reflectance of the material). In this case, the values for this area range from 900 to 938.7 cd/ m2. The last simulation done consist of a daylight grid-based radiation map (Fig. 44), that shows the solar radiation the solar cells are receiving during the whole year. According to this simulation, the maximum average value of the solar radiation in the solar cells is 753 KWh/m2, which coincides with the values obtained for the graph done with the .ill file produced by Diva and show below the image of the results. In this graph, the average values of the solar radiation received by the sensors during the daylight hours of the day (which has been set to 9, from 7:00 to 15:00) are shown, which range from less than 100 KWh/m2 during the winter months, to more than 500 KWh/m2 during spring and autumn, which is probably due to the inclination angle of the solar radiation during this months, being a more optimal angle with a surface perpendicular to the ground. These squared mono-crystalline solar cells are usually connected in series and have an efficiency of 20%, having into account that the estimated area of solar cells is 5.07 m2 (measured in the Rhinoceros model), this means that the energy produced in spring and autumn has a maximum value of 507 KWh and in winter 101.4 KWh (since Eproduced = Esupplied /m2 x efficiency x Asolar cells).

Once the efficiency of the daylighting design of he building has been analysed, is time to look at the artificial light system. The classroom lighting is automatically controlled through sensors according to presence and daylight levels, with the additional possibility of overriding both on and off. According to the SINTEF report, for the classroom lighting it is recommend to use T5 fluorescent lamps. However, these cannot be muted so that daylight control will consist in the automatic turning on

Fig. 45: Picture of a classroom interior of the blue wing, in which the luminaries of the artificial lighting system can be observed. Karin Buvik.

and off of the artificial light. On the other hand, the report also gives the possibility to use luminaries which intensity can be regulating according to the solar inclination angle. In this case, luminaries with standard fluorescent lamps should be used. Although it also warns about the significantly higher cost of this system. As part of the associated R & D project at SINTEF, this report emphasizes the importance of daylight for health, well-being, and visual impression. An average daylight factor for classrooms of 5% and minimum 2% is recommended which, as shown in the previous analysis, is fulfil for most of the cases. The report also includes an estimation of cost savings in daylight control of electrical lighting. Energy saving potential in a classroom of 84 m2 is estimated at 750 kWh/year for an on/off light control and 880 kWh/year for light control with intensity regulation. The additional costs for this lighting system with intensity control were estimated at SEK 9240 / classroom.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

Artificial lighting analysis

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

VENTILATION SYSTEM

Kvernhuset Ugdomskolen has an hybrid ventilation system, resulting of the combination of a mechanical system in the first floor and a natural ventilation system using natural driving forces, buoyancy and wind in the second one, which corresponds to the level where the main wings and the library volumes are located. This results in a minimum of power used for auxiliary fans. The natural ventilation system of the second floor is based on an underground duct system, which minimises the need of air filters, heating and cooling. The main air intake for this natural ventilation system is placed on the main entrance of the school, located on the first floor, which is a big glassed box clearly standing out from the other volumes (Fig. 46).

Fig. 47: Transversal section through the classroom areas of the main wings showing the diagram of the natural ventilation system.

The fresh ventilation air taken from the outside runs through the

Fig. 46: Pictures of the glassed box which acts as the main entrance of the school, as well as he main air intake source. Inger Andersen and Pir II.

Fig. 48: Plans of the underground concrete culverts on the basement and first floor of the school. Pir II.

buoyancy forces. These ventilation air flow can be observed in the following diagram (Fig. 47). The air flow rates are controlled through sensors according to the outdoor temperature (Fig. 50). Moreover, the mechanical driven ventilation system of the first floor has a heat recovery system installed, allowing that way to reduce the energy consumption of this integrated energy system.

The fresh air is supplied to the classrooms through valves in the upper part of the rooms, creating convective currents due to the descent of the cold air and the rise of the hot air by difference of densities, in a ventilation based on displacement. The exhausted air resulting from the natural ventilation of the second floor is evacuated through lamellas located on the vertical surfaces of the skylights, using Fig.50: Design ventilation air flow rates as a function of the ambient temperature. Barbara S. Matusiak.

According to Ogmund Sørli (one of the three architects in charge of the project from Pir II) due to the fact that the natural ventilation system of the second floor did not allow the possibility to install a heat recovery ventilation system, this natural system has been replaced nowadays by a conventional mechanical one, which on the eyes of the architect has been a mistake.

Fig. 49: Pictures of the ventilation ducts located on the “spine” of the green and the yellow wing, made out of a wooden structure and transparent polyethylene. Pir II and Karin Buvik.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

first floor inside underground concrete culverts (Fig. 48), and is later on conducted to the second floor through vertical ducts inside the recycled brick walls of the “spine” to translucent polyethylene ducts located on the upper part of this spine of the main wings (Fig. 49). The reason for these ducts on the second floor to be visible has to do with the purpose of creating a building that will serve a learning tool, goal that was set at the beginning of the project design process, allowing the students to observe how the air is conducted through the building and the space that it needs.

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole 34

WATER SYSTEM

HEATING AND COOLING SYSTEM

A wastewater cleaning facility in the lower part of the site has been installed. This cleaning plant is taking care of all the sewage. Thus, both grey and black water will be cleaned on site.

Regarding the integrated energy system in charge of the heating supply, a 360 KW heat pump has been installed in the school building, using bed rock as energy source. This heat pump is not only responsible for the space heating, but also for the domestic hot water production, and heating and cooling of the ventilation air. The heat is collected thanks to 28 wells dug into the ground up to 175 m depth, and the annual COP of this heat pump has been estimated to 3.0.

A NAVA Bed plant will clean the wastewater according to nature’s own principals. Hence, organic matter in wastewater is broken down by micro-organisms in a biofilter and phosphorus is bound to special “Leca spheres” in the phosphor filter. When the spheres are saturated with phosphorus, they are replaced with new ones. They used the spheres, which contain a lot of lime in addition to the phosphorus they have sucked, used as soil improver. This way, phosphorus is brought to the natural cycle. The purification plant is dug down and is under the school grounds. Once the water is purified, it is released into the stream that pass through the area.

1. sludge separator 2. pump well chamber 3. biofilter 4. phosphor filter 5. level sump

Fig. 51: Pictures of the ventilation ducts located on the “spine” of the green and the yellow wing, made out of a wooden structure and transparent polyethylene. Pir II and Karin Buvik.

Sapace heating Heating of ventilation air Sapace heating Tap water heating Heating of ventilation air Fans and pumps Tap water heating Lighting Fans and pumps Equipment Lighting Space cooling Equipment Cooling of ventilation air Space cooling Sum Cooling of ventilation air Sum

Energy demand in KWh/m2 Teaching wings. Second floor Administration. First floor Energy demand in KWh/m2 Teaching wings. Second floor Administration. First floor 73 41 86 52 73 41 10 11 86 52 5 35 10 11 9 20 5 35 12 30 09 020 12 2 630 0 0 196 195 2 6 196 195 2

Total

Total 60 72 60 10 1772 1310 1917 013 419 1960 4 196

Fig. 52: Estimated yearly net energy use in KWh/m heated floor area, based on a schematic design. Andresen and Dokka, 2001.

Electricity Oil Sum Electricity Oil Sum

Energy demand in KWh/m2 Teaching wings level 2 Administration level 1 Energy demand in KWh/m2 74 122 Teaching wings level 2 Administration level 1 35 14 108 136 74 122 35 14 108 136

Total 93 Total 27 120 93 27 120

Fig. 53: Estimated yearly gross energy use in KWh/m2 heated floor area, based on a schematic design. Andresen and Dokka, 2001.

Energy demand in KWh/m2

Some schools had installed heat pumps, but this was not a common energy system yet. At that time, a heat pump could reduce the heating requirement for room heating, ventilation and hot water up to approximately 70%. Therefore, when installing such an energy system it was reasonable to aim for a purchased energy quantity of less than 100 kWh/m2 /year, or even less for a really good environmental project. The energy requirement for the building was simulated using the Energy-Building data program, Version 3.0. (2001). This program is based on a dynamic calculation model that takes into account the buildingâ&#x20AC;&#x2122;s thermal inertia (thermal capacity) and thermal contribution of appliances. It also takes into account control systems for light, heating and ventilation. Thus, the total energy requirement is composed of energy requirements for heating, cooling, ventilation, lighting and equipment. The efficiency of the systems and the different energy carriers were also taken into account. The results obtained were, among other things, a gross annual energy requirement of 120 kWh/m2 heated floor space, of which 93 kWh/m2 were electricity and the remaining oil.

Energy demand in KWh/m2 Cooling of ventilation air Space cooling Equipment Lighting Fans and pumps Tap water heating Heating of ventilation air Sapace heating

Teaching wings. Second floor

100

Administration. First floor

Fig. 54: Energy demand in KWh/m2 . Own elaboration.

120

140

160

3 . Integrated energy systems analysis _ Kvernhuset ungdomsskole

When designing a school building, the environmental goals are usually that the amount of purchased energy should not exceed the norm that Norwayâ&#x20AC;&#x2122;s Water Resources and Energy Directorate (NVE) recommends for new energy efficient buildings. Fifteen years ago, the standard for climate zone South Norway, inland was 129 kWh/m2/year, and the average for new school buildings was around 200 kWh/m2/year.

Results and conclusions

As explained in the abstract of this report, the focus of this building analysis has been put in the study of the daylight design that allows to reduce the electricity consumption due to artificial lighting. In order to make clear conclusions out of this analysis, the following table of comparison has been created showing the values for active occupant

4 . Results and conclusions _ Kvernhuset ungdomsskole

ANALYSIS

behaviour. As it can be observed on the table, in general it can be concluded that the daylight design has been optimized, allowing to take maximum advantage of it so that the use of artificial lighting is minimized.

ZONE 1*

ZONE 2*

ZONE 3

ZONE 4

96% of the room area

100% of the room area

97% of the room area

83% of the room area

6.9%

8.6%

3.3%

4.7%

51% of all illuminance sensors

71% for active occupant behaviour

46% for active occupant behaviour

78% for active occupant behaviour

80% for active occupant behaviour

65% for active occupant behaviour

42% of floor area

86% of floor area

99%of floor area

99% of floor area

Shading group 1

7% of occupied hours

1% of occupied hours

Non required

Shading group 2

0% of occupied hours

Non required

22% of occupied hours

20% of occupied hours

35% of occupied hours

Daylit Area Mean Daylight Factor Minimum Daylight Factor of 2%

93% of all 100% of all illuminance illuminance sensors sensors

Mean Daylight Autonomy

69% for active occupant behaviour

Continuous Daylight Autonomy Useful Daylight Illuminance (100 < UDI < 200 lx larger than 50%)

Dynamic shading control Use of artificial lighting

(According to continuous Daylight Autonomy)

* Corrected values according to the secong Daylight Autonomy simulation after includding dynamic shading control groups.

On the other hand, the Useful Daylight Illuminance (UDI) is an indicator of the illuminance levels and can be related to user’s visual comfort or discomfort within the visual field of the room. Achieved UDI is defined as the annual occurrence of illuminances across the work plane where all the illuminances are within the range of 100 lx to 2000 lx. Hence, the degree to which UDI is not achieved because illuminances exceed the upper limit is indicative of the potential for occupant discomfort. As it is observed on the results table, only the zone 1 has a pretty high standard of visual discomfort (with an unachieved UDI of 58% of the floor area), which coincides with the results obtained from the DGP analysis explained previously on this report. Overall, it can be concluded that the daylighting in this project has been adequately exploit.

Regarding the total energy consumption calculated. It has not been possible to check whether the calculated value for the gross energy consumption coincides with the actual one. However, the resulting calculated value was well below the experience of equivalent buildings built at that time of 200 kWh/m2/year, and below the ENØK standard of 129 kWh/m2/year. Therefore, the goal of creating an energy efficient building was fulfil.

4 . Results and conclusions _ Kvernhuset ungdomsskole

It is possible to establish this conclusion thanks to the daylight autonomy values given by the simulations, which are relate to the need of electric lighting according to the user’s threshold specified. In order to make this conclusion, the values for the Continuous Daylight Autonomy (cDA) have been used. In contradistinction to the mean Daylight Autonomy (DAmean), the cDA awards partial credit in a linear fashion to values below the user defined threshold. Thus, if 300 lx were specified as the DA threshold and a specific point exceeded 300 lx during 50% of the time on an annual basis, then the cDA might result in a value of approximate 55% to 60% or more. According to this, it is possible to conclude that the need for electric light is 22% and 20% of the annual occupancy schedule for the cases of zone 1 and 2 respectively, and 35% for zones 3 and 4. Having into account the reduced number of daylight hours during the winter in Norway, these are very good standards.

Discussion

5 . Discussion _ Kvernhuset ungdomsskole

As previously said, Kevernhuset was built more than fifteen years ago. In that time, many new technologies, materials and technical equipment have been developed and are nowadays available in the market. On the other hand, the prices in some construction materials and technologies have been also decreased, becoming more costeffective.

When working with a private client with the purpose of designing a building, money is always a key factor. Most of the times, even in projects like this, where architects, constructors and even clients have the same goals and ambitions regarding sustainability and environmental impact, it is not possible to achieve all of them due to an excessive over-cost. Keeping the project within the budget is not an option, but a real need. Therefore, some of the goals set on the initial stages of the project have to be discarded or not being a priority anymore. This is, for instance, what happened with the heat recovery system for the exhaust air of the natural ventilation for the second floor. According to Eimund Skåret, Peter Blom, Trygve Hestad from the Norwegian Building Research Institute (Energy recovery possibilities in natural ventilation of office buildings, n.d.) “Heat recovery from exhaust air is the process of transferring the heat energy in the exhaust air stream to another energy carrier, suitable for transport and distribution, so that the recovered energy can be utilised in one or more of the energy systems in the building. Actual building energy systems are supply air preheating, room heating and preheating of consumer hot water”. According to the architect Ogmund Sørli, it was not possible to find a solution for installing such a system in an affordable way. Thus, the goal of having heat recovery from the exhaust air on the natural driven ventilation system had to be abandoned.

On the other hand, the decision taken years later of changing the natural ventilation system installed on the second floor of the building by a mechanical one have increased the total energy consumption, even with a heat recovery ventilation system, and ignores a natural resource that, in this climate, may allow to improve the thermal comfort up to a 20% during the hot season, which can be seen in Fig. 54. Therefore, the substitution of this natural driven system by the mechanical one is worthy of discussion. Moreover, another issue that may be once again related to budget reasons is the fact that the solar cells installed in the building have mainly a pedagogical purpose, which means that are not really used Comfort Percentages as energy suppliers. This is due to the fact that the area of solar cells is not big enough to produce a reasonable amount of energy that can supply part of the operational energy of the building. The reason for not installing a bigger area is probably the cost that this small cells had in the past. SELECTED DESIGN TECHNIQUES: 1. natural ventilation

MULTIPLE PASSIVE DESIGN TECHNIQUES

Before

After

Dec

Year

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Fig. 55: Increase in comfort percentages for Fredrikstad climate due to natural ventilation. Weather tool.

On the other hand, it is also true that this kind of technical systems do not have a big efficiency yet, even with the advancements achieved in this field. They required a high maintenance in order to get the most of the energy out of them, and some of their components do not have a very big life time, which makes replacement a significant contributor to the global price of such systems. Therefore, it is possible that solar panels instead of a photovoltaic system would be more an efficient solution. Another point to discuss is that building regulations have dramatically changed as well on the past fifteen years. They have become much more restrictive. For instance, nowadays the net energy budget for a passive house standard building in Norway has been set to 20 KWh/m2/ year, which is way below the standard of school buildings from fifteen years ago of 200 kWh/m2/year. This new standard of buildings is based on an airtight envelope, which means that materials with low U-values and high isolation thicknesses are used on the exterior envelope in order to avoid heat transfer with the exterior environment. This means that the high U-value windows that were used in Kvernhuset would not have been possible nowadays in a high efficient building. A triple low emission glass window of at least 0.8 W/mÂ˛K should be used instead.

Lastly, regarding the main energy supplier system, electric heat pumps are the less pollutant equipment regarding energy production. However, fifteen years ago, a very high contributor to the emissions of this kind of equipment were the refrigerants used as working fluid. At that time, the refrigerants used were mainly CFCs (chlorofluorocarbons) and HCFCs (hydro chlorofluorocarbons), which had very high values of ozone depletion potential (ODP) and high global warming potential (GWP). However, nowadays refrigerants in heat pumps are required to have zero ODP according to Montreal Protocol, and low GWP according to Kyoto protocol. To have a rough idea, the GWP of CO2 is equal to 1, while for the HCFCs is of the order of thousands. Nowadays, the tendency is to use HFCs (hydrofluorocarbons) which have zero ODP and lower GWPs than CFCs and HCFCs. Research is also moving towards the use of natural refrigerants, which are of three different types: ammonia, hydrocarbons (propane, methane and butane), and CO2, creating new more environmentally friendly heat pumps.

5 . Discussion _ Kvernhuset ungdomsskole

However, during the past years, the advancements in this fields have been remarkable. Solar cells and other type of photovoltaic solar systems had become more affordable and are nowadays within everyoneâ&#x20AC;&#x2122;s reach. Moreover, for the specific case of Kvernhuset, where a big roof surface is exposed to the solar radiation, the installation of such systems on it would be a possibility worthy of study.

References A. McNeil and G. Burrell, 2016. “Applicability of DGP and DGI for evaluating glare in a brightly daylit space”. Building Performance Modeling Conference. Salt Lake City, UT. Available at: file:///Users/ marta.pi.lago/Downloads/C008.pdf A. Nabil and J. Mardaljevic, n.d. “Useful daylight illuminance: A new paradigm for assessing daylight in buildings”. Institute of Energy and Sustainable Development (IESD). Montfort University. Available at: https://www.researchgate.net/publication/245385301_Useful_ daylight_illuminance_A_new_paradigm_for_assessing_daylight_in_ buildings. Advanced Buildings. Energy Performance Solutions from MBI, n.d. “Daylighting Pattern Guide_ Continuous Daylight Autonomy”. Available at: https://patternguide.advancedbuildings.net/ Eimund Skåret, Peter Blom, Trygve Hestad, n.d. “Energy recovery possibilities in natural ventilation of office buildings”. Norwegian Building Research Institute. Available at: http://citeseerx.ist.psu.edu/ viewdoc/download?doi=10.1.1.459.5185&rep=rep1&type=pdf I. Andresen, 2004. “Evaluering av Kvernhuset ungdomsskole – energi og miljø”. SINTEF Bygg og miljø. Arkitektur og byggteknikk. pdf Inoutic. The German Profile Engineers for Windows and Doors., n.d. “U-value calculation for windows”. Available at: http://www. inoutic.de/en/tips-on-window-purchase/saving-energy/u-value-forwindows/ K. Buvik, 2004. “Kvernhuset ungdomsskole – Sammendrag av FoUprosjekt knyttet til planlegging av skoleanlegget”. SINTEF Bygg og 40

miljø. Arkitektur og byggteknikk. pdf Markus Kottek, et al., n.d. “World Map of the Köppen-Geiger climate classification”. Biometeorology Group, University of Veterinary Medicine Vienna, Austria. Global Precipitation Climatology Centre, Deutscher Wetterdienst, Germany. Available at: http://koeppengeiger.vu-wien.ac.at/pdf/Paper_2006.pdf Moniflex, n.d. Available at: http://www.isoflex.se/moniflex Passiv Haus Instittut, n.d. “Window - Heat Transfer Coefficient Uw and Glazing - Heat Transfer Coefficient Ug”. Available at: http://passiv.de/ former_conferences/Passive_House_E/window_U.htm Pilkington, n.d. “Helping you. Part L of Government Building Regulations”. Available at: https://www.pilkington.com/~/media/ Pilkington/Site%20Content/UK/Reference/TableofDefaultUValues. ashx T. de Bruin-Hordijk and E. de Groot, n.d. “Lighting in schools”. Available at: http://lightinglab.fi/IEAAnnex45/publications/Technical_reports/ lighting_in_schools.pdf

u-wert.net, n.d. Available at: https://www.u-wert.net/u-wertrechner/