Design analysis and energy impacts

Design Simulation & Analysis Project 2 report Design analysis and impacts of adjacent surfaces for an office building in jakarta submitted by Ramkumar A0123482

Overview The study is to analyse the energy performance of an office building located in the city of Jakarta in terms of mean radiant temperature, total solar gain and total thermal energy for each zones and designing the best shading device to avoid glare in the interior thereby providing good daylighting performance.

Aim

To study and analyse the impact on energy performance due to the immediate adjacent blocks and compare the outputs for the different scenarios.

Design The blocks are made of prefabricated modules with openings on two sides containing the floor space area of 432 sqm across three floors. The composition of these blocks varies in response to its annex blocks such as blocks with three sides opening or blocks with annex block on top and so on as explained in the diagram. All the exposed roof has vegetation cover to bring down the energy consumption.

Figure 1: Zone with one annex block

Figure 2: Zone with two annex block

Figure 3: Zone with three annex block

Figure 4: Zone with four annex block

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Proceedings 1. To understand the sunlight hours for the entire building with 277 blocks for the north south orientation.

2. To analyse and compare the energy performance of different blocks with various adjacent scenarios.

3. To design the best shading devices for the blocks with maximum sunlight and avoid the glare inside the office space.

Software used Rhino -Grasshopper -Honey Bee & Lady bug -Energy plus -Radiance

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Zone selection To analyse the energy performance of the structure which is modular, only one floor is taken for analysis. The level in the middle of the structure is chosen for analysis, as there is no neighbouring context that has an impact on the building.

Also the blocks that are atached on top and bottom of level 8 is also assigned as thermal zones as it has impacts on the heat transfer.

Three floors above the selected level is assigned as shading devices as it cast shadows on the selected thermal zones.

Blocks above as shading surfaces Annex blocks on top Selecting LVL 8 for analysis Annex blocks below

Overall building elevation

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Assigned Thermal zones on level 8

NORTH

Blocks with no annex block (top/bottom) Blocks with annex block on top Blocks with annex block on top & bottom Blocks with annex block in bottom

Hypothesis The neighbouring blocks which is adjacent to the block has its impacts on the thermal energy of the block. For example the blocks with annex blocks on top and one side will have low thermal energy than the block which is exposed on top and botom. But the green vegetated roof on the exposed will help in bringing down the energy to 1 to 2 deg celcius.

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Glazing Each of the zones are assigned with 40% glazing

Shading device Each zone has been assigned with horizontal shading device with a depth of .5m and with interdistance of .4m considering the office space will be shaded with curtains during the work hours.

LVL 9 LVL 8 LVL 7

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Materials used Each of the zones has been assigned with the default materials for the walls, windows, interior and exterior floor.

Benefits of Vegetated roof Energy Conservation, improved thermal performance

Vegetated roof The exposed roof surfaces has been added with customised vegetated roof material

Green roof systems are recognised as providing greater thermal performance and roof insulation for the buildings they are laid on. This can vary depending on the time of the year, and the amount of water held within the system.

Cooling [summer] Poorly protected and insulated roofs can lead to substantial overheating of spaces beneath them. This can lead to the need for increased airconditioning. A green roof not only acts as an insulation barrier, but the combination of plant processes [photosynthesis and evapotranspiration] and soil processes [evapotransmission] reduces the amount of solar energy absorbed by the roof membrane, thus leading to cooler temperatures beneath the surface.

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Structure of the analysis

2. Selecting the appropriate zones for the energy performance study

1. Overall buiding scale

3. Selecting the critical zones for further

4. Selecting one zone for daylight analysis

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Preliminary Analysis The sunlight hour analysis is done for the hottest day in Jakarta for the month of May as mentioned in the weather file datas. Most of the surfaces in the east west gets more sunlight hours to a maximum of 7 hours in the east and upto 10 hours in the west.

Outdoor surface temperature

View from South East

View from South West

To begin the with the analysis the outdoor surface temperature has been simulated to understand the average surface area getting heated.

So on an average the surface outdoor temperature is around 30 to 33deg celcius. Also it is very obvious that the surfaces facing the west gets an average temperature of 40 degree celcius.

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Mean radiant temperature

zone 7

zone 13

The mean radiant temperature (MRT) is defined as the uniform temperature of an imaginary enclosure in which the radiant heat transfer from the human body is equal to the radiant heat transfer in the actual nonuniform enclosure.

zone 11

zone 9

zone 15

zone 3 zone 4 zone 16 zone 1

zone location Blocks with no annex block (top/bottom) Blocks with annex block on top Blocks with annex block on top & bottom Blocks with annex block in bottom Page 9

Observation The mean radiant temperature across the year shows that the month of May has the highest radiation particularly in zone 4 which goes high upto 28.56deg celcius.

Also it is evident from the graph that the energy consumption pattern is not the same across the year for all the zones.

For example comparing the radiant temperature for zone 1, zone 4 and zone 16 does not follow the same curve across the year.

zone 4

zone 6

This may be be due to the shading surfaces from the roof above, the sun angle and other factors.

zone 8

zone 14

zone 10

zone 1

zone 2

zone 5

zone 12 Page 10

Total Solar gain

zone 7

zone 13

Solar gain (also known as solar heat gain or passive solar gain) refers to the increase in temperature in a space, object or structure that results from solar radiation. The amount of solar gain increases with the strength of the sunlight, and with the ability of any intervening material to transmit or resist the radiation.

zone 11

zone 9

zone 15

zone 3

Blocks with no annex block (top/bottom) Blocks with annex block on top Blocks with annex block on top & bottom Blocks with annex block in bottom Page 11

Observation The total solar gain also varies with the arrangement of the zones. Some of the zones shows very obvious result like zone 4 which doesnt not have any adjacent blocks.

But when comparing the zone 13 and zone 15 on the western side, zone 15 gains more solar than zone 13.

The hottest month in Jakarta is May and the zone 4 gives the maximum value of 7.91Kwh

zone 4

zone 6

zone 8

zone 14

zone 10

zone 1

zone 2

zone 5

zone 12 Page 12

Total Thermal Energy Total thermal energy is the energy consumed by each of the zones including the energy for cooling and heating. zone 7

zone 13

zone 11

zone 9

zone 15

zone 3

Blocks with no annex block (top/bottom) Blocks with annex block on top Blocks with annex block on top & bottom Blocks with annex block in bottom Page 13

Observation The total thermal energy required for the zones remains more or less the same in the range of 12 to 15kwh per sqm per month.

On an average office building in Jakarta consumes about 230 kwh per sqm per annum.

This office building consumes 180 kwh per sqm per annum which is actually 20% reduction in the energy consumption. This can also due to he fact that all the exposed roofs has vegetated roof which by itself can reduce the total thermal energy of a building thus reducing the energy consumption for cooling in the case of Jakarta.

The zone 4 consumes the maximum of 10.4 KWh in the month of May which is reported to be the hottest month in Jakarta.

zone 4

zone 6

zone 8

zone 14

zone 10

zone 1

zone 2

zone 5

zone 12

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Stage 2 Out of the sixteen zones four of the critical blocks are chosen with different adjacent blocks scenarios and the next stage of simulations are done varying the shading device and analyse the impact of the design changes.

Blocks with no annex block (top/bottom) Blocks with annex block on top Blocks with annex block on top & bottom Blocks with annex block in bottom

The shading devices are made much denser and angular to analyse the impact of the louvres on the energy consumption.

Figure showing 0.2m shading device Page 15

0.5m Shading device

0.2m Shading device

0.5m

0.2m 0.4m

0.2m

zone 4

zone 4

zone 12

zone 12

zone 8

zone 8

zone 13

zone 13

Inference The impact of the shading device has not changed much after the change in the louvre arrangement.

Currently the energy consumption is lower than the average office usage in Jakarta. To further bring down the energy, some changes could be made in the material selection like choosing the appropriate materials, wall thickness could be increased to reduce the heat lag. Also the glazing could be made as Low E glazing to further reduce the heat radiation.

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Stage 3 The further simulations are done by using the DIVA platform to analyse the best daylighting performance.

Designing the best shading device for the zone 12.

Comparing the analysis of daylight factor, point in time illuminance and glare analysis to determine which shading device provides the best daylight.

As per the previous energy performance analysis the change in shading device does not have much impact on total thermal energy.

So this analysis will determine the shading device that allows the right amount of daylight and avoid the glare for the users inside the space.

Shading Device

0.5m 0.4m

0.5m shading

0.2m 0.2m

0.2m shading

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Daylight Factor 0.5m shading

Mean Daylight Factor = 4.24%

The daylight factor is very high which is not suitable for the office space.

0.2m shading

Mean Daylight Factor = 0.58%

The daylight factor seems very gloomy for 0.2m shading which seems very less for an office space as per the standards.

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Point in time Iluminance 0.5m shading

Mean Illuminance = 2500lux

The mean illuminance of the room is very high upto 2500lux which is not much suitable for the office space as per the standards.

0.2m shading Mean Illuminance = 700lux

The .2m shading depth with angle provides indirect lighting into the space by bouncing of the light from the metal louvres. The lux levels are at the range of 700- 750 which is still high for a general office space but can be further controlled using curtains or screens.

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Indirect light distribution in the room

The figure above shows the light bouncing inside the room reflected from the diffuse metal surface.

Common & recommended lighting levels indoor

Inference From the above analysis the 0.2m wide metall diffuse louvres at an angle of 45 degree provides better diffused daylighting.

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Glare analysis From the glare analysis it is understood that both the options does not give glare for the users as the range is much within the imperceptible glare range.

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Conclusion Thus when analysing the energy performance of a building, It is a known fact that the adjacent building blocks have impact on the thermal zones in terms of solar gain and radiant temperature thereby directly impacting the total thermal loads.

But the analysis help us understand on how many percentage it affects and to what extent it has the impacts. Thus while designing a building it will be very helpful to assign the right appropriate materials at the right orientation and thus help in value engineering of a building.

Also the energy performnace can be further optimised by using the right sizes of shading devices but also providing the required amount of daylighting inside a space. This can be further varied with different criterias such as energy performance, daylighting and ventilation inside a space.

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