Characteristics of Building Envelope that Influence the Value of Operative Temperature on Office Buildings Based on Jakarta Climate Data

Architecture is accused of being an energy user and the most significant contributor to global warming, so it is the architect's responsibility to ensure that indoor comfort conditions are achieved with little or no traditional energy. This study focuses on knowing the best Range in building envelope configurations to obtain Operative Temperature comfort values. Simulation methods is used for model this research. Software that b used for this research are EnergyPlus v8.1 and Open Studio plugin version 0.7. The results show that the temperature of operative temperature (Top) does not reach a comfort value of 25 ° C by SNI 03-6572-2001 standards. If the air temperature setting is smaller, the energy consumption of the building will be higher. In the WWR variation, intensity of energy consumption per Ta was reduced by 1 ° C by 3.68 kWh / m2. Then in the variation of SHGC, increase energy consumption value of each Ta is reduced by 1 ° C by 3.44 kWh / m2. While for shading variations, the increase in value is 3.57 kWh / m2.


ABSTRACT
Architecture is accused of being an energy user and the most significant contributor to global warming, so it is the architect's responsibility to ensure that indoor comfort conditions are achieved with little or no traditional energy.This study focuses on knowing the best Range in building envelope configurations to obtain Operative Temperature comfort values.Simulation methods is used for model this research.Software that b used for this research are EnergyPlus v8.1 and Open Studio plugin version 0.7.The results show that the temperature of operative temperature (Top) does not reach a comfort value of 25 ° C by SNI 03-6572-2001 standards.If the air temperature setting is smaller, the energy consumption of the building will be higher.In the WWR variation, intensity of energy consumption per Ta was reduced by 1 ° C by 3.68 kWh / m2.Then in the variation of SHGC, increase energy consumption value of each Ta is reduced by 1 ° C by 3.44 kWh / m2.While for shading variations, the increase in value is 3.57 kWh / m2.

INTRODUCTION
Architecture is accused of being an energy user and the most significant contributor to global warming, so it is the architect's responsibility to ensure that indoor comfort conditions are achieved with little or no traditional energy [1].Energy-efficient architecture is an architecture with the lowest possible energy requirements that can be achieved by reducing the number of resources that make sense.The heat source in the building itself can be divided into two, namely external and internal heat loads [2].The heat that comes with natural light is an example of external heat, while heat derived from body metabolism, lighting, and equipment is an example of internal heat.This aspect has a significant share in contributing to energy consumption in buildings.Thermal comfort we can talk about [3], indeed will not be separated by making the temperature indicator a benchmark.The actual indicator that must be considered in achieving the comfort level of humans inhabiting that space is the Operative Temperature value, where Operative Temperature is the average value of the sum between water temperature and mean radiant temperature and is the temperature directlyfelt by skin [4].
This study explains in more detail the use of heating systems that oppose cooling systems.This shows that the farther away the area is from the site of the outermost opening, the higher the temperature will be felt.In the case of buildings with a heating system and a sub-tropical climate with four seasons.If the building uses a cooling system, the farther the distance from the opening area, the lower the temperature felt [5].
So far, storeys buildings that use artificial ventilation just pay attention to air temperature in the cooling system / HVAC [6].The Operative Temperature value must be achieving human comfort level, where Operative Temperature is the temperature directly felt by human skin (Borgstein, 2014).This study aimed to determine the characteristics of building envelopes to attain optimal operative temperature values based on climate data.In addition, it is also associated with the amount of energy consumption in buildings when affected by a decrease in the Operative Temperature value if applied in the city of Jakarta [7].

RESEARCH METHOD
This research uses simulation methods using modelling on computer The simulation in this research was carried out computerized with the help of the superior software used [8], namely EnergyPlus v8.1 and the Open Studio plugin version 0.7 which was run on Google Sketchup v7.0 software.Modeling in this system is carried out on the middle floor with modeling only on typical floors [9].In Figure 1, the hypothetical floor dimensions are 40m x 40m.The division of zones in a typical floor model can be explained as follows, four office activity zones (air-cooled) and one core zone in the middle of the building (not air-conditioned).The naming of office zones includes east, south, west and north zones.The top and bottom floors of the simulation floor will be modeled adiabatically [10].This type of building modelling is divided into six parts from each orientation, namely two parts of the corner or angle which gets sunlight from two directions and four parts of depth.Between depth is taken as a 3.5m drive because, at that distance, the Top temperature data is obtained, significantly different from the temperature of the Top zone in the first [11].The function of the building to be studied is an office with an open plan layout set to simplify the calculation of air-cooling load (cooling load).Work time is set 5 days a week starting at 08.00-18.00.
The simulated variables include (applied to each orientation) the area of glass (WWR 30%; 40%; 50%; 60%; 65%).In this study WWR 10% -20% was very rarely applied in building design so it was not applied as a variable.Besides that, it also shows water temperature as a variable, where the variations include Ta 20 ° C, 18 ° C, 15 ° C. Then horizontal shade element variables (VSA 30,VSA 50,VSA 70,VSA 90).

Effect of WWR Variation on the Radiant Temperature Mean Value
The size of the opening is very influential on the value of Mean Radiant Temperature (TMRT) [12] .In this simulation, the application of a large number of openings from 30% to 65%, by locking the glass SHGC at a value of 0.4 (Stopsol Dark Blue type) and the value of water temperature in the HVAC setting of 25 ° C without using shading.This comparison is done to show the effect of increasing the WWR number on changes in the value of TMRT.If the larger WWR means the wider the area of the glass and the smaller the size of the massive wall.The larger the area of the glass will give effect to raise heat that get into the room which will directly affect the value of TMRT [13].Based on the figure 2, the simulation results show that the greater the ratio of the glass field will the greater the value of the value obtained.In addition, it can be seen that the simulation results showthe influence of WWR on the value of each orientation obtained that is highest in the northwest orientation and lowest in the southern orientation.The range of TMRT values when carried out by WWR variations is at a temperature of 30.49° C-39.26 ° C. From a 10% drop WWR can reduce the temperature of the Tm by approximately 1 ° C-1.5 ° C.
From the explanation above it can be explained on the Table 1 that the glass field provides the greatest contribution to indoor heat compared to a massive field or wall.Thus, increasing the area of the wall will reduce the value of TMRT so that the heat will get into the building less.Further simulation analysis is carried out by looking at the energy consumption consumed by the building.The size of the temperature or temperature is closely related to the size of the energy consumed by the building, this is because the lower the perceived value, the greater the consumption of energy used to cool the room, but despite the greater energy consumption but the occupants of the building will reach the optimal level of comfort.The table below is a table of obtaining energy consumption from WWR 40 compared to WWR 65 in conditions of HGC still 0.4, Ta 25 ° C and without using shading.
The difference in the amount of energy consumption between WWR 40% and WWR 65% is 5 kWh / m2 explain ini Table 2 dan 3.These results show the greater the WWR the greater the energy consumption.This is becausethe bigger the WWR will be the greater the heat that will be received by the building.With this condition, the greater the energy needed to be able to cool the building.
Table 3.The Figure 5 is a graph of Ta modification in WWR 30% -65% on the western wall.When the Ta setting changes to 20 ° C that meet the Top value on SNI standards, the occupant's comfort value of 25 ° C is only WWR 30%.Then changes were made again to the Ta setting to 18 ° C, the results obtained were those that were able to meet the Top SNI standards, namely WWR 35%, WWR 40% and WWR 50%.The last modification done is to change the Ta setting to 15 ° C and the whole WWR variable from 35% -65% can reach the Top value ± 25 ° C.
The graph above is a simulation result by locking the WWR variable at 40%, SHGC 0.4 and without shading.The results can be seen if the conditions can reach Top ± 25 ° C in all orientation directions, namely in the Ta setting of 18 ° C and 15 ° C. Based on the explanation above, it can be summarized that the WWR is almost always fulfilled to reach the comfort level of Top 25 ° C, which is between 30% -40%.
The Effect of Decreasing Air Temperature on Energy Consumption Intensity The level of energy consumption is influenced by the air temperature settings carried out.Decreasing the air temperature to reach air temperature has a direct impact on the energy consumption intensity of the building.The smaller the Ta temperature setting, the performance of the HVAC system will increase, resulting in higher energy consumption in the building but comfortably will have a very good effect to people that used the building.The Figure 6 below is a graph of the simulation results in several variations of WWR can show the level of increase in energy consumption from changes in Ta settings.Source: Personal Analysis, 2019.
If seen from the table 5, it can be seen that every decrease in regulation Ta will increase energy consumption.The range of increases in energy consumption per 10% WWR increase in the reduction of 25 ° C to 20 ° C is 18 kWh / m2 -20 kWh / m2.Then an increase of about 24 kWh / m2 -27.5 kWh / m2 each increases 10% WWR when the Ta is decrease to 18 ° C from 25 ° C.After that there was an increase in energy consumption of approximately 33.5 kWh / m2 -38 kWh / m2 in the reduction of Ta from 25 ° C to 15 ° C at every 10% increase in WWR.

Analysis of Variations in Shading on the Radiant Temperature Mean Value
In an effort to determine the effect of using shading on TMRT values, a simulation was carried out by locking WWR at 40%, SHGC 04, and Ta setting 25 ° C. while the simulated free variable is VSA 30, VSA 50, VSA 70 and without shading.The existence of this shading is able to reduce the value of surface inside temperature significantly.With that it is also able to reduce the TMRT value of the room.Based on the figure 12 and 13 can be seen that shading can reduce the value of surface inside temperature, the wider the shading will be the smaller surface inside temperature.The wider the shading, the more constant the temperature or temperature is from each zone.This is because the wider the shading will be more able to withstand the heat or radiation of the sun entering the building.On the Table 9 and Figure 14 with less light entering the food, it will further reduce the  Indirectly from the explanation on figure 14, if the wider the shading will decrease the surface inside temperature, the TMRT value will also decrease by applying shading.The detailed on the figure 15 and table 10.Based on Table 12, the size of the Top is closely connected to the building energy consumption.The results obtainedshowed that shading was able to reduce energy between 4 kwh / m2 11.5 kwh / m2.This depends on the length of the short shading used.The longer the shading is used, the lower the Top in the buildingwill be, so the smaller energy consumption will be smaller.
Based on the results of the TMRT and Top simulation, it was concluded that with the setting of water temperature (Ta) fixed at 25 ° C, nothing has been fulfilled to achieve a comfortable Top for occupants of 25 ° C because the lowest temperature value is still ± 28 ° C.However, based on simulations with a fixed Ta value of 25 ° C, it is sufficient to reduce or decrease the Top value by making changes to SHGC because it can reduce by ± 01 ° C-1.7 ° C.
With reference to the comparison table 13, the acquisition of Decrease Range results in theWWR variation gets the smallest value, which is in the range 0.1 ° C-0.6 ° C (every 10% reduction in WWR).This shows that this WWR variation has a big influence in increasing the Top value in the room.The larger the glass used will not only increase the cooling load value but will also create thermal discomfort in the room.

Figure 2 .
Figure 2. Graph Value of the WWR Intermediate Radiant Temperature Mean Source: Personal Analysis, 2019

Figure 3 .
Figure 3. Graph of Correlation between WWR and Operative Temperature Value Source: Personal Analysis, 2019.
Effect of Air Temperature on Operative Temperature ValueThe lowest Top temperature value when using the Ta setting of 25 ° C [14] which is 28.25 ° C.This shows on figure4that what has been done so far in designing comfort in space does not meet the appropriate standards.Then the next simulation is carried out by using air temperature (Ta) as a variable.The process carried out in the experiment is by changing the air temperature setting.Air Temperature variable values include 20°C, 18°C and 15°C.The target comfort value to be achieved is depends on the comfort value or operative temperature stated in SNI 03-6572-2001, namely 25°C.

Figure 4 .
Figure 4. Graph of Operative Temperature Value When Decreased in Air Temperature Settings Source: Personal Analysis, 2019.

Figure 5 .
Figure 5. Operative Temperature Value Chart When Performed in Decreasing Inter-WWR Temperature Water Settings Source: Personal Analysis, 2019.

Figure 6 .
Figure 6.Graph of the Value of Increase in Energy Consumption Intensity After the Decreasing of Temperature Water Settings Source: Personal Analysis, 2019.

Figure 12 .
Figure 12.Graph the value of Surface Inside Temperature and Mean Radiant Temperature at VSA 30 Source: Personal Analysis, 2019.

Figure 13 .
Figure 13.Graph of Surface Inside Temperature and Mean Radiant Temperature When Not Using Shading Source: Personal Analysis, 2019.

Figure 14 .
Figure 14.Graph Value Surface Inside Temperature between Shading Source: Personal Analysis, 2019.

Figure 15 .
Figure 15.Graph Value of Temperature Radiant Mean between Shading Source: Personal Analysis, 2019.

Table 1 .
Comparison of the Maximum Value and Minimum Surface Inside Temperature with Mean Radiant Temperature Table of Acquisition of Energy Consumption between WWR Table Comparison of Operative Temperature Values between Variables

Table 4 .
The Intensity Value of Energy Consumption (kWh / m2) between WWRs is based on a Decrease in Water Temperature Settings

Table 5 .
Difference in Value of IKE or Energy Consumption Intensity (kWh / m2) between WWR

38 Characteristics of Building Envelope that Influence the Value of Operative Temperature on Office Buildings Based on Jakarta Climate Data Nurina
Vidya Ayuningtyas, Istiana Adianti surface inside temperature and TMRT of the room.The existence of shading can reduce the surface inside temperature of approximately 1 ° C-3 ° C.Table9.Value of Surface Inside Temperature between Application Shading Source: Personal Analysis, 2019.

Table 10 .
Value of Temperature Radiant between Shading Applications

of Building Envelope that Influence the Value of Operative Temperature on Office Buildings Based on Jakarta Climate Data
Nurina Vidya Ayuningtyas, Istiana Adianti lowest Top Value at 28.61 ° C and the highest Top Value at 30.83 ° C.Figure 16.Graph of the Operative Temperature Value between Shading Source: Personal Analysis, 2019.
Table of Energy Consumption Gain between Shading

Table 13 .
Table Comparison of Operative Temperature Values between Variables Source: Personal Analysis, 2019.