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JOTUN Cool Shades Impact of the TSR Value on the Users Comfort and the Energy Performance of Buildings ai³ Werner Jager

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JOTUN Cool Shades

Impact of the TSR Value on the Users Comfort and the Energy Performance of Buildings

ai³ Werner Jager

JOTUN Coatings

Impact of the TSR Value on the Users Comfort and the Energy Performance of Buildings

1 09.10.2013

Exclusion of warranty:

All tables, graphical charts and results presented within this report are made with the

highest possible care. A warranty for the correctness of the charts, data, values,

figures and conclusions cannot be given and is excluded at any point in time.

Furthermore the results are calculated with numerical assumptions, formulas and

parameters that could differ in real conditions. A direct comparison between the

results presented and discussed in this report and the situation on site is not possible.

A claim on warranty due to the use of those results is invalid at any point in time.

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Table of Contents

1. General Page 3

2. Results

a. Interior Comfort Page 9

b. Energy Requirement of Buildings

i. Module A Page 13

a) Discussion of Results Doha in Qatar Page 15

b) Discussion of Results Shanghai in China Page 19

c) Discussion of Results Istanbul in Turkey Page 23

d) Discussion of Results Bangkok in Thailand Page 27

e) Discussion of Results Sydney in Australia Page 31

ii. Module B Page 35

a) Discussion of Results Doha in Qatar Page 36

b) Discussion of Results Istanbul in Turkey Page 38

c) Discussion of Results Bangkok in Thailand Page 40

iii. Module C

Discussion of Results Doha in Qatar Page 42

3. Literature Page 44

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Executive Summary

1. General The goal of the project was to investigate the impact of the Total Solar Reflectance of the envelope surfaces on the energy requirement of building. The simulations are made for 5 locations Istanbul in Turkey, Doha in Qatar, Bangkok in Thailand, Shanghai in China and Sydney in Australia. The simulations did have focused on 2 major aspects and impact areas of TSR coatings for the building envelope: Interior comfort and energy requirements for heating, cooling mainly. To assess the impact of the TSR value of coatings on the interior comfort, the interior surface temperature of aluminum window systems were calculated. The boundary conditions had been: Interior air temperature +20°C /+25°C, exterior air temperature +35°C and 1000 W/m² solar irradiation. Furthermore 2 window types have been investigated. The one is representing the major solution in countries around Middle East and is a thermally non insulated window system solution, aluminum based. The second window system is thermally highly insulted and represents the major solution for climates was mainly heating energy requirements, e.g. central and north Europe, Asia or America. The energy requirements are simulated on a building model representing a residential building block, currently used in Middle East climates containing 80 apartments on 20 floors. The total amount of simulations is defined into 3 major modules. Orientation of the building is ideally south. In Module A all opaque surface areas of the envelope (window frames + vertical walls + roof) show the same TSR value at the same time. In Module B the TSR values are varied for the window frames independently from the rest of the opaque surface areas (vertical walls + roof) and vice versa. In this simulation runs the question was investigated to which extend does the framing of the window and curtain wall elements impact the heating and cooling energy requirements of the building type selected. This impact was investigated for different TSR values of the remaining opaque building envelope area.The thermal insulation standard used for all areas and components is low, to represent the current building practice in Middle East climates. Module C is discussing the question of how the thermal insulation level of the window frame is influencing the choice of TSR value when a „cooling climate“ is considered. The TSR values selected for the Energy Requirement of Buildings simulation runs are 5%, 10%, 30%, 50% 70% and 90%. For the Interior Comfort investigation the TSR values are varied as follows: 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%. Software Description The software solutions chosen are

flixo professional version 7 from Infomind.ch for the Interior Comfort investigations and

ArchiWizard version 2.7.1 from RayCreatis.com for the Energy Requirements of Buildings.

The flixo professional version 7 simulates acc. to the following European standards: •EN ISO 10211: 2007 (Thermal bridges in building construction - Heat flows and surface temperatures - detailed calculations) •EN ISO 10077-2: 2012 (Thermal performance of windows, doors and shutters - Calculation of thermal transmittance - Part 2: Numerical method for frames)

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The ArchiWizard software kernel and solution is based on the International and European Standard EN ISO 13790:2008 and acc. to its origin contains further regulations and definitions based on the French Energy Performance of Buildings Regulation RT 2005 and RT 2012. The EN ISO 1379:2008 Standard gives calculation methods for assessment of the annual energy use for space heating and cooling of a residential and a non-residential building. The Standard includes the determination and calculation of:

„The heat transfer by transmission and ventilation of the building zone when heated or cooled to constant internal temperature“(Quote ISO Organization); Dynamic change of room temperature, e.g. caused by solar irradiation into the building is not possible to be done, but the dynamic behavior of building components is taken into account and here the EN ISO 13786 is used for.

The contribution of internal (person, equipment, artificial lighting etc.)and solar heat gains to the building heat balance;

The annual energy needs for heating and cooling, to maintain the set-point temperatures in the building; the set/point temperatures are pre-defined but can be chosen independently as well. Furthermore latent heat is not considered, indicating that latent heat storage materials such as PCMs (Phase Change Materials) cannot be taken into account yet;

The annual energy use for heating and cooling of the building, using input from the relevant system standards referred to in ISO 13790:2008 and specified in Annex A.

„ISO 13790:2008 also gives an alternative simple hourly method, using hourly user schedules (such as temperature set-points, ventilation modes or operation schedules of movable solar shading). “ (Quote ISO Organization) „Procedures are given for the use of more detailed simulation methods to ensure compatibility and consistency between the application and results of the different types of method. ISO 13790:2008 provides, for instance, common rules for the boundary conditions and physical input data irrespective of the calculation approach chosen. “(Quote ISO Organization)

Thermal bridges of the building are pre-set acc. to RT 2005, but have been defined to be 0.1 W/ (m ▪ K) for the calculation runs. Here the connecting areas between wall areas, wall to roof and wall to basement ceiling are meant, as for the thermal bridges window to wall are defined acc. to the EN ISO 10211.

The heat flux through the basement ceiling is calculated acc. to EN 13370. Window and Curtain wall thermal parameters are defined in accordance to the EN ISO 6946 and the EN ISO 10077 Part 2.

The lighting and solar irradiation characteristics of the window and curtain wall components are defined acc. to EN 410 and EN 13363 Part 1.

Air infiltration into the building and the ventilation of the building is based on the Standards EN 15243 and the RT 2005.

Also the hourly exposure of building components to the sky and its induced long wave infra-red exchange is considered in accordance with RT 2005 definitions.

The hot water demand is calculated acc. to RT 2012 definitions as well as

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The utilization scenarios of the building zones.

Hourly solar irradiation is used to calculate o the hourly natural lighting of areas within the building and o The impact of shading of exterior envelope components by the Ray tracing

method. The use of Archiwizard therefore provides a backing of validated International and European

Standards and Energy Saving Regulations. Making the results achieved easy to be compared.

The results are indicators of energy demand and are not the final energy demand or the

primary energy demand figures, as for these factors the real energy supply system has to be

considered as well, which is dependent of the location and the final equipment and energy

source chosen to operate the building.

Picture 1.1: International and European Standards and National Regulations used in Archiwizard V2

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Important aspect of the related energy requirements is the set point for heating and cooling

as well as the use scenario chosen. These have been defined by the French Energy Saving

Regulations definitions for “collective housing” buildings (RT 2012). For these building type

the room air temperature during presence of users is defined to be between + 19°C and

below + 28°C. Meaning that e.g. the inner room air temperature is at + 19°C, the heating

device is supplying additional heating energy. Reaching + 28°C, the cooling device is supplying

additional cooling energy.

Within the scenario of “collective housing” the base assumption is that the temperature

range between + 19°C and + 28°C is used, whenever users are normally present. During the

day users go to work or are at school, so here the facility system is reflecting this by being

operated by average set points, allowing in that time frame a min. temperature of + 16°C and

max. temperature of + 30°C.

These temperature settings and the “collective housing” scenario of operation leads to high

energy requirements as the set points + 19°C/ + 28°C are also applied during the night time.

In addition the RT 2012 prescribes for “collective housing” the use of a ventilation system. In

the simulation runs the ventilation system is a mechanical air extraction system with heat

exchanger. The energy losses by air renewal and envelope air permeability are therefor also

taken into account, when the overall heating and cooling demand is calculated.

The energy balance is therefore a complete analysis of the energy gains (mainly solar and

internal) vs. the energy losses (mainly losses by thermal transmission, air renewal and

infiltration, radiation towards the sky) leading to heating, cooling, ventilating and lighting

energy demands.

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Picture 1.2: Temperature set points for heating and cooling defined acc. to RT 2012 and

used in Archiwizard V2

Picture 1.3: Scenario of annual heating and cooling defined acc. to RT 2012 and

used in Archiwizard V2

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The variation on TSR value of the exterior envelope surfaces is, due to the building model chosen,

also impacting the artificial lighting demand, as the interior surface properties are linked to the

exterior ones. Due to the low energy requirement value for artificial lighting, which is around factor

20 times and more lower, than the requirement for heating and/ or cooling, the contribution can be

accepted within the frame of that study.

Picture 1.4: Characteristics of the opaque wall, thermal bridges and openings used

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2. Results a. Interior Comfort

The simulation shows that a high TSR value on the outside surfaces of aluminum window systems is reducing the interior surface temperatures of that building component. A lower inner surface temperature leads also to an increased interior comfort of the users. The less thermally insulated the window system is the bigger is the possible improvement. The more thermally insulated the window system is the less the TSR value variation is impacting that interior surface temperature. Higher insulated systems have in general lower interior surface temperatures than less insulated solutions. The dependency of the interior comfort from the inner surface temperatures is described by W. Frank: „Raumklima und thermische Behaglichkeit“, Berichte aus der Bauforschung, Heft 104, Berlin 1975. Here the interior comfort is described to be depended from the inner air temperature and the average surface temperature of the room surfaces. In analogy to that dependency the surface temperatures of the window frames were assessed in terms of comfort. The impact of the interior surface temperatures on the comfort of users is mainly due to the long wave infrared heat exchange between these surfaces and the human skin. Figure 1: Room climate and thermal comfort acc. to W. Frank

If the inner room air temperature is defined to be +20°C, surface temperatures between approx. +19°C and +25°C are defined to be comfortable (dark green area in Fig. 1), surface temperatures in the range of approx. +16°C to +19°C, as well as from approx. +25°C to +28°C are defined to be acceptable (bright green area in Fig. 1). Surface temperatures below approx. +16°C and above approx. +28°C are defined to become uncomfortable (silver white area in Fig.1). Under that assumptions and parameters set the highest surface temperature of a thermally non insulated aluminum system (here Uframe = 7.1 W/(m²K)) is getting close

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to +41°C with a TSR value of 5%. The same window solution, but coated with a TSR 90% coating has an interior surface temperature of +31°C. Reaching therefore 10 K lower inner surface temperatures just by chosen a coating with a high TSR value. A highly thermally insulated window system (here Uframe = 1.3 W/(m²K)) achieves

interior surface temperatures between +23°C (TSR 90%) and +25°C (TSR 90%).

Here the solar irradiation is absorbed at the outside surfaces of the window frame and the glazing unit, as well as partly at the inner glazing bead due to solar transmission through the transparent glazing unit. Figure 2.1: Interior surface temperature of window systems (+20°C inner air temperature)

Here the highly thermally broken solution stays at all TSR surface value variations within the comfortable zone, but improving even its position with higher TSR values. The thermally non insulated systems comes closer and closer to the acceptable comfort zone the higher the TSR value of the coating gets, at a TSR of 90% it is only 1 K away from that zone under the chosen boundary conditions. As a potential consequence one can see, that higher TSR values achieve best results when applied on better thermally broken window systems, as than they will be able to reach the comfortable zone easier. Defining the inner room air temperature to be +25°C, the area comfortable (dark green color area in Fig.1) is not possible to be reached due to the already high interior air temperature. Surface temperatures in the range of approx. +10°C to +24°C, are defined to be acceptable (bright green area in Fig.1). Surface temperatures below approx. +10°C and above approx. +24°C are defined to become uncomfortable. The highest surface temperature of a thermally non insulated aluminum system is getting close to +43°C with a TSR value of 5%. The same window solution, but coated with a TSR 90% coating has an interior surface temperature of +33°C. A highly thermally insulated window system achieves interior surface temperatures between +28°C (TSR 5%) and +30°C (TSR 90%). Conclusion form that additional variation of the interior room air temperature is, that a higher interior room air temperature leads to higher inner surface temperatures as

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well, leading more to discomfort for the user of the room. Window frame coatings with high TSR values lead to an increased comfort aspect for the user. The combined use of high TSR coating and thermally insulated window frames achieve the comfort zone much easier, than each measure individually. The Figure 2.1 (+20°C inner air temperature) or the The Figure 2.2 (+25°C inner air temperature) can be taken as a chart where the possible results of a combination between TSR value and Uframe value (thermal energy transmission coefficient defined in EN ISO 10077) can be predefined, as the upper blue line is the result for a Uframe value of 7.1 W/(m²K) and the lower red line is marking a Uframe value of 1.3 W/(m²K). If the Uframe value is between both values, a linear interpolation seems to lead to a sufficiently accurate estimation.

Figure 2.2: Interior surface temperature of window systems (+25°C inner air temperature)

At indoor air temperature levels set to be +25°C only a combination of highly thermally broken window systems and high TSR values (≥ 50%) can lead to interior surface temperatures of the window system in the comfort zone acceptable. The simulations of the impact of the coating TSR value on the inner surface temperature of windows indicate that thermally non insulated window and curtain wall systems benefit the most from coatings with high TSR values. To reach the defined comfort zones according to literature, one should use better thermally insulated window and curtain wall systems. The comfort zone is defined by the inner air temperature set. The higher the inner room air temperature is chosen the higher as well the thermal insulation of the window and curtain wall systems should become to reach or come closer to the comfort zone defined acc. to W. Frank.

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In climates with cooling demand like e.g. Middle East or the summer period in Europe an additional aspect, not reflected by the work of W.Frank nor part of Fig.1, is that in case of high solar absorption, combined with low thermally insulated building components and reduced heat transfer coefficients at the exterior and interior surfaces plus a high solar absorption of surfaces can lead to very high temperatures of these surfaces. ai³ made here an additional simulation run to estimate in worst case scenario what surface temperatures could be possible, choosing the parameters as follows:

Uframe value of 7.1 W/(m²K)

inner room air temperature to be +25°C

exterior ambient air temperature to be +35°C

Solar irradiation 1000 W/m²

Reduced interior heat transfer coefficient 0.25 (m²K)/W e.g. minimizing convection and radiation exchange can occur by an internal curtain close to the window

Reduced exterior heat transfer coefficient 0.08 (m²K)/W e.g. minimizing convection can occur by the building geometry

TSR value of the window frame 5%

Here the interior surface temperature of the window frame can get higher than +50°C. At different parameter settings this temperature could get even higher. Acc. to German Risk Research done (SKIEA 1979) such high material and surface contact temperatures can lead to skin irritations and burns, when touched over a certain period of time (Figure 2.3). If the simulated non-thermally insulated window would have been coated with a TSR 90% powder solution, the temperature on the inner surface of the component would have been at +35°C and, acc. to simulation settings, away from any risk of skin irritation or burns when touched by people.

Figure 2.3: Interior surface temperature of components and risk scenario (SKIEA 1979 and

gesundheitsbeurteilung.de)

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b. Energy Requirement of the Building The simulation work is split into 2 parts

i. Module A Module A is meant as general approach to the question of how the variation of Total Solar Reflectance TSR values for the entire opaque envelope components is impacting the annual energy requirements for heating, cooling, ventilating and hot water supplies. Here all envelope components that are exposed to solar radiation and are opaque get the same TSR value. The envelope components are the roof, the vertical concrete walls with exterior plaster and the window frames of the transparent components. The insulation glazing units (2-IGU) self-maintain their specific TSR properties and are not part of the general TSR variation. The concrete wall with plaster area can also become a lightweight curtain wall structure with aluminum cladding of the opaque area and still the presented simulation results can be valid, if the curtain wall structure has the same thermal insulation level and absorbing surface area as the simulated concrete wall with plaster. To use these results also for a lightweight curtain wall solution, it has to be ensured in addition, that the thermal storage capacity chosen here (very heavy) for the entire building is still reached. The 20 store building, representing 80 apartments, is chosen to represent the economic construction solutions done today in climates such as Middle East. The window systems are made out aluminum and indicate, with a thermal heat transfer coefficient of ≥ 7 W/ (m² ▪ K), the use of a non-thermally insulated solution. Also the roof and the vertical walls are composed out of concrete, mainly without an additional insulation layer such as mineral wool or foamed PS plates. The inertia of those building components are selected to be heavy, as no additional insulation layer is impacting the heat storage capacity of these building materials. As HVAC system a simple double flux exhaust and supply system without additional heat exchanger is chosen. The artificial lighting is done by light bulbs with a luminance of 12 Lumen per Watt. To compare the impact of higher TSR values of the building components, the reference TSR value has been chosen in Module A to be 30%, representing surface color from „dark grey sparkle“ to „sand”.

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Picture 3: Surface color indications from „dark grey sparkle“ to „sand” representing TSR values around 30% (Source JOTUN).

The weather data used derives from METEONORM 7, the latest edition of Meteotest.com, and is representing hourly values for temperatures of the ambient air and the sky, diffuse and direct solar irradiation, IL luminance and relative humidity.

Picture 4: Screenshot of the Meteonorm 7 data file selection - Example DOHA in Qatar

The building is using the utilization scenarios of a multiple residential building type, defined in RT 2012.

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Discussion of Results

a. Doha in Qatar

Graph 1.1 is containing the total Energy requirements, the pure heating requirements as well as the pure cooling requirements in [kWh] for the year, for the DOHA climate in Qatar. The location of the related weather station is the International Airport. The climate at Doha can be named “Cooling Climate” as the demand of heating energy is negligible low. The use of coatings with high TSR properties lead to a reduction of cooling loads, which is nearly similar to the reduction of the total energy requirement of the building for heating, cooling, lighting and ventilating as well as warm water suppliers.

Graph 1.1: Energy Requirements for various TSR values - Example DOHA in Qatar

Between a TSR of 5% and a TSR of 90% the total energy requirement difference is more than 400,000 kWh of which only the difference in cooling energy requirement is close to 380,000 kWh a year. Comparing to a building envelope TSR Value of 90%, the reference case TSR 30% has an additional total energy demand of 14%, the additional cooling energy demand is above 17%. But also for a lower building envelope TSR value of 70% or 50%, the reference case TSR 30% has an additional total energy demand of more than 8% (TSR 70%) respectively more than 4% (TSR 50%) , the additional cooling energy demand is above 10% (TSR 70%) respectively more than 5% (TSR 50%). Building envelopes with low TSR values realize a higher demand of total energy requirements. The lower the TSR value the higher becomes the energy demand.

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Table 1: Energy Requirements for various TSR values - Example DOHA in Qatar

For the energy balance, the solar contribution in combination with the heat sources, that are available internally, are the biggest impact sources all year long. During the summer period (May to September) the thermal transmission through the opaque building components and the losses of energy due to the needed air renewal, which need higher air conditioning demand, add to the overall energy balance. On the other side the low thermally insulated opaque building components support during the winter season (November to April) the flow of passive solar gains from inside to outside, reducing the additional demand for cooling during that period. Similar support, but lower in numbers, is provided by the air renewal and the radiation towards the sky. For the energy balance cooling demand becomes dominant from April to November. With higher TSR values of the envelope components the energy balance is less and less impacted by the solar contribution. The value for the envelope transmissions are even increased during the period May to September, as higher TSR values are also impacting the radiation exchange towards the sky, which potentially support the reduction of cooling energy requirements during that period. Vice versa that effect leads to lower envelop transmission for the winter period November to April. (Graph 1.2 and 1.3) The energy demand is dominated by cooling requirements from April to November. Hot water and ventilation needs are almost constant throughout the year. The energy demand for lighting is comparatively low and mostly constant during the year, when discussed on a monthly scale. This effect is similar for low as for higher TSR values of the considered opaque building envelope components. (Graph 1.4 and 1.5)

TSR 5% TSR 10% TSR 30% TSR 50% TSR 70% TSR 90%A.1.1 A.1.2 A.1.3 A.1.4 A.1.5 A.1.6

Heating Requirements in [kWh] 1.573 1.677 2.225 3.116 4.385 6.205

Cooling Requirements in [kWh] 1.947.241 1.926.690 1.839.853 1.747.896 1.661.348 1.568.661

Total Energy Requirements in [kWh] 2.566.013 2.545.564 2.453.681 2.348.865 2.254.526 2.151.660

Variation Heating in [%] -41,4 -32,7 0,0 28,6 49,3 64,1

Variation Cooling in [%] 5,5 4,5 0,0 -5,3 -10,7 -17,3

Variation Total in [%] 4,4 3,6 0,0 -4,5 -8,8 -14,0

Variation Heating in [kWh] -652 -548 0 891 2.160 3.980

Variation Cooling in [kWh] 107.388 86.837 0 -91.957 -178.505 -271.192

Variation Total in [kWh] 112.332 91.883 0 -104.816 -199.155 -302.021

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Graph 1.2: Energy Balance - Example DOHA in Qatar Variation A.1.1 TSR 5%

Graph 1.3: Energy Balance - Example DOHA in Qatar Variation A.1.6 TSR 90%

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Graph 1.4: Energy Demand - Example DOHA in Qatar Variation A.1.1 TSR 5%

Graph 1.5: Energy Demand - Example DOHA in Qatar Variation A.1.6 TSR 90%

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b. Shanghai in China

Graph 2.1 is containing the total Energy requirements, the pure heating requirements as well as the pure cooling requirements in [kWh] for the year, for the Shanghai climate in China. The location of the related weather station is close to the city center. The climate at Shanghai can be named “Heating Climate with Cooling Requirements” as the demand of heating energy is around 4 times the one for cooling. The use of coatings with high TSR properties lead to a reduction of cooling loads, but increase the demand for heating energy. For the chosen building type and setting, the cooling energy reductions by building envelope components with higher TSR values is in numbers bigger than the increase for heating. So an overall reduction of the total energy requirement could be achieved.

Graph 2.1: Energy Requirements for various TSR values - Example Shanghai in China

Between a TSR of 5% and a TSR of 90% the total energy requirement difference is around 70,000 kWh of which only the difference in cooling energy requirement is close to 150,000 kWh a year, indicating that higher TSR values of the envelope components lead to higher heating demands, which are partly compensating the achievable cooling energy reductions. Comparing to a building envelope TSR Value of 90%, the reference case TSR 30% has an additional total energy demand of 2%, the additional cooling energy demand is above 47%, but the TSR 30% reference building provides 7% less in heating energy requirements annually. But also for a lower building envelope TSR value of 70% or 50%, the reference case TSR 30% has an additional total energy demand of close to

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2 % (TSR 70%) respective around 1% (TSR 50%) , the additional cooling energy demand is above 28% (TSR 70%) respective more than 13% (TSR 50%). Thus indicating that even for a “Heating Climate with Cooling Requirements” like Shanghai, the use of colors with a higher TSR values could provide additional total energy savings. Building envelopes with low TSR values realize the higher demand of total energy requirements. The lower the TSR value the higher becomes the total energy demand.

Table 2: Energy Requirements for various TSR values - Example Shanghai in China

For the energy balance, the heating need becomes most dominating during the period from November to April. Solar irradiation is impacting the energy balance throughout the year, supporting energy savings in winter due to passive solar gains, but impacting the cooling energy demand during summer. The major cooling period is from June to September. The values for envelope transmissions indicate in addition, that the envelope components should be higher thermally insulated to realize more energy saving. With higher TSR values of the envelope components the energy balance is less and less impacted by the solar contribution, compensated by increased heating energy demands in winter. (Graph 2.2 and 2.3) The energy demand is dominated by heating requirements from November to April and by cooling requirements from June to September. May and October are the month dominated by the needs for air renewal and hot water, which are almost constant throughout the year. The energy demand for lighting is comparatively low and mostly constant during the year, when discussed on a monthly scale. This effect is similar for low as for higher TSR values of the considered opaque building envelope components. (Graph 2.4 and 2.5)

TSR 5% TSR 10% TSR 30% TSR 50% TSR 70% TSR 90%A.2.1 A.2.2 A.2.3 A.2.4 A.2.5 A.2.6

Heating Requirements in [kWh] 1.159.356 1.164.772 1.188.924 1.218.241 1.249.147 1.284.446

Cooling Requirements in [kWh] 370.816 361.355 323.654 285.696 251.902 219.291

Total Energy Requirements in [kWh] 2.147.370 2.143.326 2.125.547 2.104.032 2.089.894 2.080.557

Variation Heating in [%] -2,6 -2,1 0,0 2,4 4,8 7,4

Variation Cooling in [%] 12,7 10,4 0,0 -13,3 -28,5 -47,6

Variation Total in [%] 1,0 0,8 0,0 -1,0 -1,7 -2,2

Variation Heating in [kWh] -29.568 -24.152 0 29.317 60.223 95.522

Variation Cooling in [kWh] 47.162 37.701 0 -37.958 -71.752 -104.363

Variation Total in [kWh] 21.823 17.779 0 -21.515 -35.653 -44.990

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Graph 2.2: Energy Balance - Example Shanghai in China Variation A.2.1 TSR 5%

Graph 2.3: Energy Balance - Example Shanghai in China Variation A.2.6 TSR 90%

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Graph 2.4: Energy Demand - Example Shanghai in China Variation A.2.1 TSR 5%

Graph 2.5: Energy Demand - Example Shanghai in China Variation A.2.6 TSR 90%

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c. Istanbul in Turkey

Graph 3.1 is containing the total Energy requirements, the pure heating requirements as well as the pure cooling requirements in [kWh] for the year, for the Istanbul climate in Turkey. The location of the related weather station is close to the Mediterranean Sea. The climate at Istanbul can be named “Heating Climate with Cooling Requirements”, similar as Shanghai climate, as the demand of heating energy is around 4 times the one for cooling. The use of coatings with high TSR properties lead to a reduction of cooling loads, but increase the demand for heating energy. For the chosen building type and setting, the cooling energy reductions by building envelope components with higher TSR values is in numbers bigger than the increase for heating. So an overall reduction of the total energy requirement could be achieved.

Graph 2.1: Energy Requirements for various TSR values - Example Shanghai in China

Between a TSR of 5% and a TSR of 90% the total energy requirement difference is around 70,000 kWh of which only the difference in cooling energy requirement is close to 120,000 kWh a year, indicating that higher TSR values of the envelope components lead to higher heating demands, which are partly compensating the achievable cooling energy reductions. Comparing to a building envelope TSR Value of 90%, the reference case TSR 30% has an additional total energy demand of 2.5%, the additional cooling energy demand is arround 80%, but the TSR 30% reference building provides 7% less in heating energy requirements annually.

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But also for a lower building envelope TSR value of 70% or 50%, the reference case TSR 30% has an additional total energy demand of close to 2 % (TSR 70%) respective above 1% (TSR 50%) , the additional cooling energy demand is around 45% (TSR 70%) respective more than 19% (TSR 50%). Thus indicating that even for a “Heating Climate with Cooling Requirements” like Shanghai, the use of colors with a higher TSR values could provide additional total energy savings. Building envelopes with low TSR values realize the higher demand of total energy requirements. The lower the TSR value the higher becomes the total energy demand.

Table 3: Energy Requirements for various TSR values - Example Istanbul in Turkey

For the energy balance, the heating need becomes most dominating during the period from November to April. Solar irradiation is impacting the energy balance throughout the year, supporting energy savings in winter due to passive solar gains, but impacting the cooling energy demand during summer. The major cooling period is from June to September. The values for envelope transmissions indicate in addition, that the envelope components should be higher thermally insulated to realize more energy saving. With higher TSR values of the envelope components the energy balance is less and less impacted by the solar contribution, compensated by increased heating energy demands in winter. (Graph 3.2 and 3.3) The energy demand is dominated by heating requirements from November to April and by cooling requirements from June to September. May and October are the month dominated by the needs for air renewal and hot water, which are almost constant throughout the year. The energy demand for lighting is comparatively low and mostly constant during the year, when discussed on a monthly scale. This effect is similar for low as for higher TSR values of the considered opaque building envelope components. (Graph 3.4 and 3.5)

TSR 5% TSR 10% TSR 30% TSR 50% TSR 70% TSR 90%A.3.1 A.3.2 A.3.3 A.3.4 A.3.5 A.3.6

Heating Requirements in [kWh] 1.029.446 1.033.381 1.051.188 1.073.951 1.098.702 1.127.360

Cooling Requirements in [kWh] 237.890 230.130 197.493 165.152 136.620 109.922

Total Energy Requirements in [kWh] 1.884.534 1.880.702 1.860.300 1.837.034 1.822.658 1.815.256

Variation Heating in [%] -2,1 -1,7 0,0 2,1 4,3 6,8

Variation Cooling in [%] 17,0 14,2 0,0 -19,6 -44,6 -79,7

Variation Total in [%] 1,3 1,1 0,0 -1,3 -2,1 -2,5

Variation Heating in [kWh] -21.742 -17.807 0 22.763 47.514 76.172

Variation Cooling in [kWh] 40.397 32.637 0 -32.341 -60.873 -87.571

Variation Total in [kWh] 24.234 20.402 0 -23.266 -37.642 -45.044

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Graph3.2: Energy Balance - Example Istanbul in Turkey Variation A.3.1 TSR 5%

Graph 3.3: Energy Balance - Example Istanbul in Turkey Variation A.3.6 TSR 90%

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Graph 3.4: Energy Demand - Example Istanbul in Turkey Variation A.3.1 TSR 5%

Graph 3.5: Energy Demand - Example Istanbul in Turkey Variation A.3.6 TSR 90%

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d. Bangkok in Thailand

Graph 4 is containing the total Energy requirements, the pure heating requirements as well as the pure cooling requirements in [kWh] for the year, for the Bangkok climate in Thailand. The location of the related weather station is close to the city center. The climate at Bangkok can be named “Cooling Climate” as the demand of heating energy has become 0. The use of coatings with high TSR properties lead to a reduction of cooling loads and therefore becomes a major measure for potential energy reduction.

Graph 4.1: Energy Requirements for various TSR values - Example Bangkok in Thailand

Between a TSR of 5% and a TSR of 90% the total energy requirement difference is more than 900,000 kWh of which only the difference in cooling energy requirement is close to 880,000 kWh a year. Comparing to a building envelope TSR Value of 90%, the reference case TSR 30% has an additional total energy demand of 30%, the additional cooling energy demand is close to 39%. But also for a lower building envelope TSR value of 70% or 50%, the reference case TSR 30% has an additional total energy demand of more than 18% (TSR 70%) respective close to 9% (TSR 50%) , the additional cooling energy demand is above 22% (TSR 70%) respective more than 10% (TSR 50%). Building envelopes with low TSR values realize the higher demand of total energy requirements. The lower the TSR value the higher becomes the energy demand.

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Table 4: Energy Requirements for various TSR values - Example Bangkok in Thailand

For the energy balance, the solar contribution in combination with the heat sources, that are available internally, are the biggest impact sources all year long and at a similar level month by month, with low differences between the months. From May to July the cooling demand becomes higher than during the rest of the year. .

Graph4.2: Energy Balance - Example Bangkok in Thailand Variation A.5.1 TSR 5%

TSR 5% TSR 10% TSR 30% TSR 50% TSR 70% TSR 90%A.4.1 A.4.2 A.4.3 A.4.4 A.4.5 A.4.6

Heating Requirements in [kWh] 0 0 0 0 0 0

Cooling Requirements in [kWh] 2.489.119 2.440.588 2.236.749 2.024.928 1.822.787 1.613.646

Total Energy Requirements in [kWh] 3.106.317 3.057.763 2.845.524 2.619.231 2.407.889 2.191.521

Variation Heating in [%] 0,0 0,0 0,0 0,0 0,0 0,0

Variation Cooling in [%] 10,1 8,4 0,0 -10,5 -22,7 -38,6

Variation Total in [%] 8,4 6,9 0,0 -8,6 -18,2 -29,8

Variation Heating in [kWh] 0 0 0 0 0 0

Variation Cooling in [kWh] 252.370 203.839 0 -211.821 -413.962 -623.103

Variation Total in [kWh] 260.793 212.239 0 -226.293 -437.635 -654.003

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Graph 4.3: Energy Balance - Example Bangkok in Thailand Variation A.4.6 TSR 90%

With higher TSR values of the envelope components the energy balance is less and less impacted by the solar contribution and the internal contributors, like people and equipment get dominant. (Graph 4.2 and 4.3) The energy demand is dominated by cooling requirements throughout the year. Hot water and ventilation needs are almost constant throughout the year and are factor 8 to 12 below the cooling ones. The energy demand for lighting is comparatively low and mostly constant during the year, when discussed on a monthly scale. This effect is similar for low as for higher TSR values of the considered opaque building envelope components. (Graph 4.4 and 4.5)

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Graph 4.5: Energy Demand - Example Bangkok in Thailand Variation A.4.1 TSR 5%

Graph 4.6: Energy Demand - Example Bangkok in Thailand Variation A.4.6 TSR 90%

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c. Sydney in Australia

Graph 5 is containing the total Energy requirements, the pure heating requirements as well as the pure cooling requirements in [kWh] for the year, for the Sydney climate in Australia. The location of the related weather station is close to the city center. The climate in Sydney can be named “Moderate Climate” as the demand of heating energy as well exists as the demand for cooling. The use of coatings with high TSR properties lead to a reduction of cooling loads, but increase the demand for heating energy. For the chosen building type and setting, the cooling energy reductions by building envelope components with higher TSR values is in numbers bigger than the increase for heating. So an overall reduction of the total energy requirement could be achieved.

Graph 5.1: Energy Requirements for various TSR values - Example Sydney in Australia

Between a TSR of 5% and a TSR of 90% the total energy requirement difference is more than 60,000 kWh of which only the difference in cooling energy requirement is close to 80,000 kWh a year. Comparing to a building envelope TSR Value of 90%, the reference case TSR 30% has an additional total energy demand of 4%, the additional cooling energy demand is above 360%. But also for a lower building envelope TSR value of 70% or 50%, the reference case TSR 30% has an additional total energy demand of more than 4% (TSR 70%) respective more than 3% (TSR 50%) , the additional cooling energy demand is above 150% (TSR 70%) respective more than 50% (TSR 50%). Building envelopes with low TSR values realize the higher demand of total energy requirements. The lower the TSR value the higher becomes the

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energy demand. At TSR value of 5% the amount of cooling energy is nearly as high as the amount of heating energy, whereas at a TSR value of 90% the cooling energy demand is times 15 lower than the heating energy demand.

Table 5: Energy Requirements for various TSR values - Example Sydney in Australia

For the energy balance, the solar contribution in combination with the heat sources, that are available internally, are the biggest impact sources all year long. During the period June to August additional heating requirements have to be satisfied by the HVAC (Heating Ventilating Air Conditioning) system, whereas from December until March cooling is needed. For the whole year the losses of energy due to air renewal, radiation towards the sky and thermal transmission through the envelope have a similar amount than the gains induced by solar and internal contribution. This is leading to comparatively low overall energy requirement for the chosen building type and parameter settings. With higher TSR values of the envelope components the energy balance is less and less impacted by the solar contribution. Higher TSR value lead to an increased heating demand in the period from May until September, but lead to strongly reduced cooling loads for the rest of the year. (Graph 5.2 and 5.3) The energy demand is dominated by hot water supply requirements for the whole year. From May to September heating demands happen, with highest values in June and July. Cooling starts from October until April, but with remarkable amounts only from December to March, with peaks in December, January and February. This effect is similar for low as for higher TSR values of the considered opaque building envelope components, but with the effect, that with higher TSR values the need for cooling is low. Indicating that by some additional measures (e.g. optimized HVAC system or envelope components) the need for a cooling device can be discussed, leading eventually to an additional cost saving option. (Graph 5.4 and 5.5)

TSR 5% TSR 10% TSR 30% TSR 50% TSR 70% TSR 90%A.5.1 A.5.2 A.5.3 A.5.4 A.5.5 A.5.6

Heating Requirements in [kWh] 138.770 141.197 152.025 165.395 180.257 199.384

Cooling Requirements in [kWh] 102.258 94.727 64.441 40.989 25.353 13.841

Total Energy Requirements in [kWh] 858.226 853.094 825.430 800.053 791.551 794.012

Variation Heating in [%] -9,6 -7,7 0,0 8,1 15,7 23,8

Variation Cooling in [%] 37,0 32,0 0,0 -57,2 -154,2 -365,6

Variation Total in [%] 3,8 3,2 0,0 -3,2 -4,3 -4,0

Variation Heating in [kWh] -13.255 -10.828 0 13.370 28.232 47.359

Variation Cooling in [kWh] 37.817 30.286 0 -23.452 -39.088 -50.600

Variation Total in [kWh] 32.796 27.664 0 -25.377 -33.879 -31.418

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Graph 5.2: Energy Balance - Example Sydney in Australia Variation A.6.1 TSR 5%

Graph 5.3: Energy Balance - Example Sydney in Australia Variation A.5.6 TSR 90%

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Graph 5.4: Energy Demand - Example Sydney in Australia Variation A.5.1 TSR 5%

Graph 5.5: Energy Demand - Example Sydney in Australia Variation A.5.6 TSR 90%

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ii. Module B Module B is meant to differentiate the impact of the window frame coating from the coating of the remaining opaque building envelope. Taking the results of Module A into account the simulation was run for the climates of Doha, Bangkok and Istanbul. The Istanbul results of Module A have been close to the ones of Shanghai, so an additional simulation run will bring similar results. Sydney has provided an overall low energy demand, mainly dominated by auxiliary energy requirements like hot water supply or air renewal ventilation. So an additional simulation run will hardly bring more detailed understanding. The 20 store building, representing 80 apartments, is chosen to represent the economic construction solutions done today in climates such as Middle East. The window systems are made out aluminum and indicate, with a thermal heat transfer coefficient of ≥ 7 W/ (m² ▪ K), the use of a non-thermally insulated solution. Also the roof and the vertical walls are composed out of concrete, mainly without an additional insulation layer such as mineral wool or foamed PS plates. The inertia of those building components is selected to be heavy, as no additional insulation layer is impacting the heat storage capacity of these building materials. As HVAC system a simple double flux exhaust and supply system without additional heat exchanger is chosen. The artificial lighting is done by light bulbs with a luminance of 12 Lumen per Watt. The reference TSR value has been chosen in Module B to be 50%, representing surface color „yellow“ or „apple”. Within the variation of the window frame coating TSR value, the TSR value of the remaining opaque building envelope was kept at 50% and vice versa, when the remaining opaque building envelope was varied in the area of the TSR value, the window frame coating TSR value was kept at 50%. This was selected to also get a different reference point than Module A, so that the discussion gets an additional view.

Picture 5: Surface color indications „yellow” representing TSR values around 50% (Source JOTUN).

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Discussion of Results a. Doha in Qatar

Table 6 is containing the total Energy requirements, the pure impact of the window frame coating TSR variation and the pure impact of the remaining opaque building envelope TSR value variations in [kWh] for the year. The location of the related weather station is the International Airport. The climate at Doha can be named “Cooling Climate” as the demand of heating energy is negligibly low. The use of coatings with high TSR properties lead to a reduction of cooling loads. Table 6 contains the following data:

The total energy requirement, if the entire opaque building envelope (window frames + vertical walls + roof) has the same TSR value

The Impact of the envelope (vertical walls + roof) by varying the related TSR value between 5 % and 90%. Here the window frame coating TSR is kept at 50%.

The Impact of the window frames by varying the related TSR value between 5 % and 90%. Here the vertical wall + roof coating TSR are kept at 50%.

The variation of the vertical wall + roof TSR value between 5% and 90% results in an overall energy requirement difference of around 270,000 [kWh] a year (Table 6, row Impact of Envelope in [kWh]), whereas the variation of the window frames coating TSR value variation between 5% and 90% achieves a difference of close to 140,000 [kWh] (Table 6, row Impact of window frames in [kWh]). Anyhow the window frames contribute in relation a lot more to the entire energy saving, when high TSR value coatings are applied, as their current ratio transparent window area to opaque building envelope (concrete wall, roof and floor) is just at 15% (Picture 1.4), relative to the North oriented vertical wall area the window opening area, facing North orientation, is here 30%. Similar for the South oriented surfaces. The East and West oriented window opening areas are 20% of the respectively considered vertical surface of each orientation. Reason for the comparatively high impact is caused by the low thermal performance of the window frames; thermal transmission from outside to the inside of the building is high in that area. Especially in climates with cooling energy as major demand, than the application of coatings with high TSR value are favorable. The impact on the total energy requirement is nearly linear between 10% and 90% of TSR, so that a direct interpolation of other TSR than the additionally simulated 30% - 50% - 70% seems acceptable. (Graph 6) As example that could mean that compared to applying

a standard “yellow” color (TSR 50%) on a window frame , the use of the JOTUN “apple” Cool shades color (TSR 60%) will reduce the overall energy requirement by more than 16,000 [kWh],

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a standard “Dark grey” color (TSR 9%) on a window frame , the use of the JOTUN “birch” Cool shades color (TSR 30.7%) will reduce the overall energy requirement by more than 40,000 [kWh]

under the chosen building and building component settings and climate.

Graph 6: Energy Requirements for various TSR values - Example DOHA in Qatar

Table 6: Energy Requirements for various TSR values - Example DOHA in Qatar

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b. Istanbul in Turkey

Table 7 is containing the total Energy requirements, the pure impact of the window frame coating TSR variation and the pure impact of the remaining opaque building envelope TSR value variations in [kWh] for the year.The location of the related weather station is close to the Mediterranean Sea. The climate at Istanbul can be named “Heating Climate with Cooling Requirements. The use of coatings with high TSR properties leads to a reduction of cooling loads, but only when applied on the remaining envelope are vertical walls + roof. The use of coatings with high TSR values lead to nearly no impact, when the whole year is summed up from an energy requirement point of view (Graph 7). Reason is, that the cooling energy reductions (Summer period) achieved by applying high TSR value coatings on window frames is compensated entirely by the additional heating needs (Winter season) induced by the thermally non insulated aluminum window frames. Table 7 contains the following data:

The total energy requirement, if the entire opaque building envelope (window frames + vertical walls + roof) has the same TSR value

The Impact of the envelope (vertical walls + roof) by varying the related TSR value between 5 % and 90%. Here the window frame coating TSR is kept at 50%.

The Impact of the window frames by varying the related TSR value between 5 % and 90%. Here the vertical wall + roof coating TSR are kept at 50%.

The impact on the total energy requirement is nearly linear between 10% and 90% of TSR, so that a direct interpolation of other TSR than the additionally simulated 30% - 50% - 70% seems acceptable. (Graph 7) As example that could mean that compared to applying

a standard “yellow” color (TSR 50%) on a window frame , the use of the JOTUN “apple” Cool shades color (TSR 60%) will increase the overall energy requirement by more than 600 [kWh], (Table 7, row Impact of window frames in [kWh] ~ (Value 50%+value70%)/2)

a standard “Dark grey” color (TSR 9%) on a window frame , the use of the JOTUN “birch” Cool shades color (TSR 30.7%) will increase the overall energy requirement by around 240 [kWh] (Table 7, row Impact of window frames in [kWh] ~ (Value 10% - value 30%))

under the chosen building and building component settings and climate. This low impact of high TSR values leads to the indication that for that climate conditions a window system with a higher thermally insulation level could be favorable.

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Graph 7: Energy Requirements for various TSR values - Example Istanbul in Turkey

Table 7: Energy Requirements for various TSR values - Example Istanbul in Turkey

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c. Bangkok in Thailand

Table 8 is containing the total Energy requirements, the pure impact of the window frame coating TSR variation and the pure impact of the remaining opaque building envelope TSR value variations in [kWh] for the year. The location of the related weather station is the International Airport. The climate at Doha can be named “Cooling Climate” as the demand of heating energy is 0. The use of coatings with high TSR properties lead to a reduction of cooling loads, which is nearly similar to the reduction of the total energy requirement of the building for heating, cooling, lighting and ventilating as well as warm water suppliers. Table 8 contains the following data:

The total energy requirement, if the entire opaque building envelope (window frames + vertical walls + roof) has the same TSR value

The Impact of the envelope (vertical walls + roof) by varying the related TSR value between 5 % and 90%. Here the window frame coating TSR is kept at 50%.

The Impact of the window frames by varying the related TSR value between 5 % and 90%. Here the vertical wall + roof coating TSR are kept at 50%.

The variation of the vertical wall + roof TSR value between 5% and 90% results in an overall energy requirement difference of around 670,000 [kWh] a year, whereas the variation of the window frames coating TSR value variation between 5% and 90% achieves a difference of close to 240,000 [kWh]. Anyhow the window frames contribute in relation a lot more to the entire energy saving, when high TSR value coatings are applied, as their current ratio transparent window area to opaque building envelope (concrete wall, roof and floor) is just at 15% (Picture 1.4), relative to the North oriented vertical wall area the window opening area, facing North orientation, is here 30%. Similar for the South oriented surfaces. The East and West oriented window opening areas are 20% of the respectively considered vertical surface of each orientation. Reason for the comparatively high impact is caused by the low thermal performance of the window frames; thermal transmission from outside to the inside of the building is high in that area. Especially in climates with cooling energy as major demand, than the application of coatings with high TSR value are favorable. The impact on the total energy requirement is nearly linear between 10% and 90% of TSR, so that a direct interpolation of other TSR than the additionally simulated 30% - 50% - 70% seems acceptable. (Graph 8) As example that could mean that compared to applying

a standard “yellow” color (TSR 50%) on a window frame , the use of the JOTUN “apple” Cool shades color (TSR 60%) will reduce the overall energy requirement by more than 30,000 [kWh],

a standard “Dark grey” color (TSR 9%) on a window frame , the use of the JOTUN “birch” Cool shades color (TSR 30.7%) will reduce the overall energy requirement by more than 70,000 [kWh]

under the chosen building and building component settings and climate.

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The results indicate, that under this climate condition, all building envelope components (vertical wall + roof+ window frames) should be coated with high TSR value paints to achieve the max possible energy savings.

Graph 8: Energy Requirements for various TSR values - Example Bangkok in Thailand

Table 8: Energy Requirements for various TSR values - Example Bangkok in Thailand

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iii. Module C Module C is result of the total energy simulations of Module A and B to investigate what is the impact of TSR value variation combined with the thermal insulation level of the window frame. To assess the dependency one has chosen the climate of Doha in Qatar and 2 thermal insulation level for the window frames:

Thermally highly insulated window system with Uframe = 1.5 W/(m²K)

Thermally non insulated window system with Uframe = 7.0 W/(m²K)

The comparison shows that thermally broken windows reduce also in „cooling climates“ the total energy requirements annually, expressed in kWh even more than non-thermally broken solutions. The higher the insulation level of the window frames the less does the TSR value of the coating influence the reduction of the energy requirements. In all cases a thermally lower insulated window system will lead to higher energy consumption in Doha, than a better thermally insulated window system. The difference is higher for low TSR values and lower for high TSR values. While at a TSR value of the coating of 5% the difference between thermally highly insulated window system and non-insulated one is more than 110,000 [kWh] per year, the difference becomes less than 40,000 [kWh] per year for a TSR value of 90%. (Graph 9) A reading out of that could be that for lower TSR values a better thermally insulated window system is preferred, while at higher TSR values the need for thermally insulation of the window frames becomes less dominant for the Doha climate conditions.

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Graph 9: Energy Requirements for various TSR values, depending on the thermal insulation of the

window frames - Example Doha in Qatar

Table 9: Energy Requirements for various TSR values, depending on the thermal insulation of the

window frames - Example Doha in Qatar

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3. Literature

[1] W. Frank: „Raumklima und thermische Behaglichkeit“, Berichte aus der Bauforschung, Heft 104, Berlin 1975

[2] EN ISO 10211: 2007 Thermal bridges in building construction - Heat flows and surface temperatures - detailed calculations

[3] EN ISO 10077-2: 2012 Thermal performance of windows, doors and shutters - Calculation of thermal transmittance - Part 2: Numerical method for frames

[4] METOTEST: metonorm Global Meteorological Database, Handbook Part I Software Version 7.1.0, June 2013

[5] RayCreatis: ArchiWIZARD Esquisse V2.5 et versions ulterieures, Methode de calcul, November 2012, ISO-2012-11-06/ NRJ rev. 2