Daylight and Thermal Performance of Office Buildings in Ankara Ece Durmaz1 and Simos Yannas2 Sustainable Environmental Design, Architectural Association Graduate School, London, UK, ecedurmaz.92@gmail.com 2 Sustainable Environmental Design, Architectural Association Graduate School, London, UK, simos@aaschool.ac.uk.com 1
Abstract: With little regulation over energy consumption and a climate of cold winters and warm summers, the lack of benchmarks and built exemplars is a serious barrier to the development of an environmentally responsible architecture in Ankara, Turkey. The paper focuses on office buildings and draws upon the findings of recently completed research based on computational studies, using Radiance for daylighting and Energy Plus for thermal simulations, to explore the potential of passive design strategies taking account of orientation, external obstructions, solar protection and operational schedules including ventilation strategies. Keywords: Thermal Performance, Daylight Performance, Ventilation Strategy, Office Building, Ankara
Introduction According to national statistics some 470 office buildings were given building permits in the Turkish capital of Ankara in 2015 (TurkStat, 2016). Considering that the building sector is one of the largest energy consumers, it is crucial to follow-up current and future trends in occupancy and appliance use and how these affect internal heat gains and energy demand. There has been little research in Turkey on this topic especially in response to climate change. Johnston et. al (2011) described two likely future scenarios; one, where developments in technology would reduce the loads represented by appliances and artificial lighting (energy conscious scenario), and another where more and larger appliances (multiple monitors, media walls, etc.) would cause a massive increase in energy use (techno explosion scenario). The present paper summarises recent research (Durmaz, 2016) that looked at both of these scenarios as well as drawing comparisons with historical weather data and current operation of office buildings in Ankara. Climate Ankara is located in the central Anatolia region at latitude of 39o56’N and longitude 32o52’ E. Owing to its inland location winter months are cold and snowy, summers are hot and dry. Peak daily maximum temperatures can rise to 33oC in summer with minima as low as -20oC in winter (Fig. 1). Predictions for the year 2050 suggest an average increase of some 2oC compared to recent historical data. Thus, future overheating problems should be considered while coping with the low winter temperatures. The high diurnal temperature fluctuations provide good potential for night-time cooling during summer. The adaptive thermal comfort band was calculated according to EN 15251 for Building Category II under present and future scenarios.
TEMPERATURE | oC 40 COLD MILD 30 20 10 0 -10 -20 J F M
RADIATION | WH/M2 1200 MILD COLD 1000 800 600 400 200 0 O N D
WARM
A
M
J
J
A
S
DRY BULB MEAN TEMP. | OC DRY BULB TEMP. | OC COMFORT BAND | OC GLOBAL HOR. RAD. | WH/M2 DIRECT NORMAL RAD. | WH/M2 DIFFUSE RADIATION | WH/M2
Fig1. Monthly diurnal averages for Ankara and adaptive comfort band according to EN15251 - Category II Source: Meteonorm 7
Analytic Work Daylight Analysis – Part 1: Solar Protection Strategies Daylight simulations were performed with Radiance using the Ladybug and Honeybee user interfaces. A room of depth 6.0m and floor-to-ceiling height 3.2m was used throughout (Fig. 2). The periods selected for study include the most problematic times for each window orientation. The different solar protection devices considered by the study were tested under both overcast and sunny sky conditions. The simulation parameters are listed in Table 1. Figure 3 shows details of the solar protection devices that were assessed. For south-facing openings an overhang of 1.5m was assumed in conjunction with translucent or opaque horizontal blades. For east-facing openings, horizontal foldable panel and vertical shading devices were modelled. For west and north orientations, variants of vertical devices were assessed. The figure summarises the results highlighting the best shading strategy for each orientation. The simulation results showed that all orientations except for north require solar protection on openings to control illumination levels (Fig. 3). Translucent shading devices perform better than opaque elements and can eliminate the need for artificial lighting during daytime even when the shading devices are in place. As can be seen in Figure 3, translucent vertical shading and horizontal foldable elements performed similarly on east-facing openings. The horizontal foldable panel has the advantage that it does not impair the view. The north facade required internal roller due to over illumination next to the window.
Table1. Daylight Simulation Parameters TRANSMITTANCE
GENERAL AREA CLEAR HEIGHT WINDOW TO WALL RATIO (WWR) OCCUPANCY HOURS CONTEXT MEASUREMENT PLANE COMFORT RANGE
22.5M
GLAZING
135 m 3.2 m 50% (Sill height: 80cm) 09:00 - 18:00 No 80 cm above floor 300 - 2000 lux 2
0.65
REFLECTANCE WALL FLOOR CEILING FURNITURE
0.65 0.45 0.85 0.60
6M 3.2M FLOOR TO CEILING HEIGHT
INDOOR
OUTDOOR
GLAZING EXTERNAL VT: 0.65 I WWR: 50%
Fig2. Configuration of shoe-box model
EAST
SOUTH
21ST OF SEPTEMBER, 10:00
21ST OF SEPTEMBER, 12:00 30270 LUX
6
5
4
3
2
OVERCAST
1
LUX 2400 2000 1600 1200 800 400 0M 0
4212 LUX
6
SUNNY
1: NO SHADING 2: HOR. FOLD. PANEL 3: VER. SHADING
1: NO SHADING 2 & 3: HOR. FOLD. PANEL & VER. SHADING
DETAILS: 2: HOR. FOLD. PANEL
5
VT: 0.15 CLOSED
W: 145CM | VT: 0.15 42o TILTED
4
3
1: NO SHADING 2: TRAN. SHADING 3: VER. SHADING
2
1
1: NO SHADING 2: TRAN. SHADING 3: VER. SHADING DETAILS: 2: TRAN. SHADING 65o
3: VER. SHADING
W: 145CM | R: 0.85 OPEN
LUX 2400 2000 1600 1200 800 400 0 0M
SUNNY
DETAILS: 2: TRAN. SHADING
W: 145CM | VT: 0.15 OPEN
1: OVERHANG 2: TRAN. BLADES 3: HOR. BLADES
DETAILS: 2: TRAN. BLADES
DETAILS: 2: TRAN. BLADES
3: HOR. BLADES
3: HOR. BLADES
W: 55CM | VT: 0.15 85o TILTED
W: 55CM | R: 0.85 65o TILTED
21ST OF JUNE, 17:00
30500 LUX
5
0M
SUNNY
NORTH
21ST OF SEPTEMBER, 14:00
OVERCAST
1
W: 55CM | R: 0.85 MID-PART 30o TILTED
WEST
6
2
W: 55CM | VT: 0.15 MID-PART 30o TILTED
3: VER. SHADING 42o
3
1: OVERHANG 2: TRAN. BLADES 3: HOR. BLADES
DETAILS: 2 & 3: HOR. FOLD. PANEL & VER. SHADING
W: 190CM | VT: 0.15 FOLDED
4
OVERCAST
LUX 2000 1600 1200 800 400 0
65o
8747 LUX
6
5
4
3
OVERCAST
1: NO SHADING 2: VER. FOLD. PANEL 3: VER. SHADING
1
SUNNY
1: NO SHADING 2: VER. FOLD. PANEL 3: VER. SHADING
DETAILS: 2: TRAN. SHADING
W: 145CM | VT: 0.15 65o TILTED
W: 145CM | VT: 0.25 FOLDED
3: VER. SHADING
3: VER. SHADING
W: 145CM | R: 0.85 65o TILTED
2
W: 190CM | VT: 0.25 OPEN
LUX 2000 1600 1200 800 400 0M 0
DETAILS: 2: TRAN. SHADING 25o
W: 145CM | VT: 0.25 HALF CLOSED
3: VER. SHADING
W: 190CM | VT: 0.25 25o TILTED
Fig3. Room sections showing daylight penetration with openings of different orientation and different shading strategies under sunny and overcast sky in Ankara Source: Ladybug + Honeybee
Daylight Analysis – Part 2: Determining Depth For these studies the plan depth was varied in the range of 8.0-10.0m with one of its side looking into a three-sided atrium (Figs. 4 and 5). On the street side, the obstruction angle was assumed to be of 30 degrees from window sill. Vertical shading devices (VT: 0.25) were assumed for atrium roof and vertical glazing in the west facing atrium. Orientation of the atrium was varied between north and west in further studies. For this, shading devices were only applied to atrium roof and north facade left unprotected. On the atrium side of the new
shoe-box, glazing was assumed to have a visible light transmittance of 0.85. Daylight factors (DF), the useful daylight illuminance (UDI), the daylight autonomy (DA) and glare risk were calculated to assess daylighting performance. As expected, Fig. 6 shows that obstruction from buildings across the street results in lower DF values in all cases. With daylighting incoming from two sides, the CIBSE (1999) minimum requirement of 2% daylight factor was achieved for south, east and west oriented offices even when the plan depth was extended to 10m depth. A wide circulation zone was positioned near the center of the room with the workstations placed closer to the facades. For rooms with north-facing openings the 8.0m depth gave better results. UDI predictions are summarized in Figure 6. Low UDI values near windows are an indication of over-illumination that may cause glare. For this study workstations were assumed to be positioned at a distance of 0.5m from the window for the south-facing cases, Fig. 6. This was increased to 1.0m for east and west facing offices. The UDI pattern on the west-facing case was not homogenous within 1.0m setback due to the nature of the vertical shading devices. On north-facing cases workstations were positioned at a distance of 1.4m from the facade. The Daylight Glare Probability (DGP) was found to be below 0.35, corresponding to imperceptible glare. A higher prediction of 0.43 was obtained for west-facing openings fitted with vertical shading devices under overcast sky. This problem can be eliminated by tilting the vertical shading devices. INDOOR (ATRIUM)
8M / 10M
22.5M
3.2M FLOOR TO CEILING HEIGHT
42o OUTDOOR
Fig4. Hypothetical context and dimensions of new shoe-box model
CORRIDOR 1.5M DEPTH ATRIUM ROOF SHADING VT: 0.25 ATRIUM SHADING (FOR WEST FACING ATRIUM) VT: 0.25
CASE 1: GLAZING INTERNAL 10M DEPTH I VT: 0.85 I WWR: 65% CASE 2: GLAZING INTERNAL 8M DEPTH I VT: 0.85 I WWR: 50% GLAZING EXTERNAL VT: 0.65 I WWR: 50%
30o OBSTRUCTION ANGLE URBAN CANYON 42o
Fig5. Configuration of atrium and new shoe-box model
EAST
INDOOR 65 WWR 50 WWR
EAST
INDOOR 65 WWR 50 WWR 10
9
8
7
6
5
SOUTH
INDOOR 65 WWR 50 WWR
OUTDOOR % 16 OUTDOOR12 % 8 16 4 12 4 3 2 1 0M 0 8 8M | NO OBSTRUCTION 4 8M | WITH OBSTRUCTION 4 3 2 1 0M 0
SOUTH
INDOOR 65 WWR 50 WWR 10
10M | NO OBSTRUCTION 10M | WITH OBSTRUCTION 9 8 7 6 5 2%10 INDOOR - 2000LUX) | OVERCAST 10M |UDI NO(100 OBSTRUCTION 8M STATE | NO OBSTRUCTION 10 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 9 2% 8 7 INDOOR UDI (100 - 2000LUX) | OVERCAST STATE 6
W: 190CM | VT: 0.15 FOLDED OVERCAST STATE UDI (100-2000LUX): 73% HOR. PANEL71% MEAN FOLD. DA (300LUX): W: 190CM | VT: 0.15 FOLDED GLARE ANALYSIS UDI (100-2000LUX): 73% SEP 21,DA 10:00 MEAN (300LUX): 71% DGP: 0.28
10 5 9 4 8 3 7 2 6 1 5 0 4 OUTDOOR 3 2 1 SUNNY STATE 0 HOR. FOLD.OUTDOOR PANEL W: 190CM | VT: 0.15 CLOSED STATE SUNNY UDI (100-2000LUX): 67% HOR. PANEL39% MEAN FOLD. DA (300LUX): W: 190CM | VT: 0.15 CLOSED GLARE ANALYSIS UDI (100-2000LUX): 67% SEP 21,DA 10:00 MEAN (300LUX): 39% DGP: 0.24
GLARE ANALYSIS
GLARE ANALYSIS
1M SETBACK 1M SETBACK
WEST
OVERCAST STATE HOR. FOLD. PANEL
SEP 21, 10:00 DGP: 0.28
OUTDOOR % WEST 16 INDOOR OUTDOOR12 65 WWR 50 WWR % 8 16 4 12 10 9 8 7 6 5 4 3 2 1 0M 0 8 10M | NO OBSTRUCTION 8M | NO OBSTRUCTION 4 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 2%10 9 8 7 6 5 4 3 2 1 0M 0 INDOOR - 2000LUX) | OVERCAST 10M |UDI NO(100 OBSTRUCTION 8M STATE | NO OBSTRUCTION 10 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 9 2% 8 7 INDOOR UDI (100 - 2000LUX) | OVERCAST STATE 6
1M SETBACK
OVERCAST STATE
1M SETBACK TRAN. SHADING W: 145CM | VT: 0.15 OPEN OVERCAST STATE UDI (100-2000LUX): 75% TRAN. SHADING MEAN DA (300LUX): 68% W: 145CM | VT: 0.15 OPEN GLARE ANALYSIS UDI (100-2000LUX): 75% SEP 21,DA 14:00 MEAN (300LUX): 68% DGP: 0.43
GLARE ANALYSIS SEP 21, 14:00 DGP: 0.43
65o 65
o
10 5 9 4 8 3 7 2 6 1 5 0 4 OUTDOOR 3 2 SUNNY STATE 1 TRAN. SHADING 0 W: 145CM | OUTDOOR VT: 0.15 o 65 TILTEDSTATE SUNNY UDI (100-2000LUX): 74% TRAN.DA SHADING MEAN (300LUX): 52% W: 145CM | VT: 0.15 o 65 TILTED GLARE ANALYSIS UDI (100-2000LUX): 74% SEP 21,DA 14:00 MEAN (300LUX): 52% DGP: 0.30
8
7
5
W: 55CM | VT: 0.15 MID - PART 30o TILTED GLARE ANALYSIS UDI (100-2000LUX): 78% SEP 21,DA 12:00 MEAN (300LUX): 83% DGP: 0.31
10 5 9 4 8 3 7 2 6 1 5 0 4 OUTDOOR 3 2 1 SUNNY STATE 0 OUTDOOR TRAN. BLADES W: 55CM | VT: 0.15 85o TILTEDSTATE SUNNY UDI (100-2000LUX): 77% TRAN.DA BLADES MEAN (300LUX): 46% W: 55CM | VT: 0.15 o 85 TILTED GLARE ANALYSIS UDI (100-2000LUX): 77% SEP 21,DA 12:00 MEAN (300LUX): 46% DGP: 0.25
GLARE ANALYSIS
GLARE ANALYSIS
0.5M SETBACK 0.5M SETBACK
OVERCAST STATE TRAN. BLADES
W: 55CM | VT: 0.15
o MID - PART 30STATE TILTED OVERCAST
UDI (100-2000LUX): 78%
TRAN. BLADES MEAN DA (300LUX): 83%
SEP 21, 12:00 DGP: 0.31
SEP 21, 12:00 DGP: 0.25
NORTH
INDOOR 65 WWR 50 WWR
OUTDOOR % NORTH 16 INDOOR OUTDOOR12 65 WWR 50 WWR % 8 16 4 12 10 9 8 7 6 5 4 3 2 1 0M 0 8 10M | NO OBSTRUCTION 8M | NO OBSTRUCTION 4 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 2%10 9 8 7 6 5 4 3 2 1 0M 0 OUTDOOR - 2000LUX) | NO SHADING 10M |UDI NO(100 OBSTRUCTION 8M | NO OBSTRUCTION 0 1.4M 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 1 SETBACK 2% 2 3 OUTDOOR UDI (100 - 2000LUX) | NO SHADING 4 1.4M SETBACK
NO SHADING STATE NO SHADING
0 5 1 6 2 7 3 8 4 INDOOR 5 6 7 8 INDOOR
UDI (100-2000LUX): 71%
MEAN DA (300LUX): 85% NO SHADING STATE
NO SHADING
UDI (100-2000LUX): 71% MEAN (300LUX): 85% GLAREDA ANALYSIS JUN 21, 17:00 DGP: 0.27
GLARE ANALYSIS SEP 21, 14:00 DGP: 0.30
6
10M | NO OBSTRUCTION 10M | WITH OBSTRUCTION 9 8 7 6 5 2%10 INDOOR - 2000LUX) | OVERCAST 10M |UDI NO(100 OBSTRUCTION 8M STATE | NO OBSTRUCTION 10 10M | WITH OBSTRUCTION 8M | WITH OBSTRUCTION 9 2% 8 7 INDOOR UDI (100 - 2000LUX) | OVERCAST STATE 6
SEP 21, 10:00 DGP: 0.24
INDOOR 65 WWR 50 WWR
9
OUTDOOR % 16 OUTDOOR12 % 8 16 4 12 4 3 2 1 0M 0 8 8M | NO OBSTRUCTION 4 8M | WITH OBSTRUCTION 4 3 2 1 0M 0
%
%
UDI LEGEND
0
20 40 60 80 100
0
20 40 60 80 100
UDI LEGEND
GLARE ANALYSIS JUN 21, 17:00GLARE PROBABILITY DAYLIGHT DGP: 0.27 IMPERCEPTIBLE: DGP < 0.35 PERCEPTIBLE: 0.35 < DGP < 0.4 INTOLERABLE: DGP > 0.45 DAYLIGHT GLARE PROBABILITY IMPERCEPTIBLE: DGP < 0.35 PERCEPTIBLE: 0.35 < DGP < 0.4 INTOLERABLE: DGP > 0.45
Fig6. DF plots (top), UDI (middle) and DGP (bottom) Source: Ladybug + Honeybee
Thermal Analysis Thermal simulations were undertaken with Energy Plus using the Open Studio plugin for Google SketchUp. The building model used was that for the â&#x20AC;&#x153;Daylight Simulations - Part 2â&#x20AC;?. Key input data for the simulations are listed in Table 2 and Figure 7. Case A is based on the minimum standards of the TS825 Regulation (2008) for Region III. Case B represents typical construction in Ankara. Case C stands for best practice. A number of variants and operational conditions were studied and the results are summarized in Figure 8. Space heating and cooling loads were calculated for set points of 20oC and 26oC respectively. The simulations showed that differences in external obstruction did not have a significant impact on cooling loads owing to high summer sun angles. However, on East-West facing variants, the urban canyon had a significant effect in reducing cooling loads. Space heating loads increased, but by no more than 5 kWh/m2 in all cases. Application of solar protection reduced cooling loads significantly, especially for Case C. Application of night shutters from November to mid-April improved performance in all cases. The efficacy of the night shutters was found to be directly related with the airtightness of the facade. The effect of higher air exchange rates, applied from May to October, varied. Table2. General inputs and 3 envelopes defined for thermal simulations CASE B
CASE C
INFILTRATION 0.75 ACH FRESH AIR REQUIREMENT 1.03 ACH
CASE A
0.5 ACH 1.03 ACH
0.3 ACH 1.03 ACH
WWR EXT. WALL U VALUE GLAZING U VALUE
50% 50% 0.5 W/m2K 0.17 W/m2K 1.55 W/m2K 1.55 W/m2K
GENERAL INPUTS AREA VOLUME OCCUPIED HOURS
225 m2 (22.5 x 10m) 720 m3 09:00 - 18:00 weekdays only
OCCUPANCY DENSITY 7.2 m2/person LIGHTING POWER DENSITY 7 W/m2 EQUIPMENT POWER DENSITY 12 W/m2 W/M2 12 8 4 0
3
6
9 12 15 18 21 24
EQUIPMENT GAINS OCCUPANT GAINS LIGHTING GAINS OCCUPIED HOURS
KWH/M2 120 80 39 40 21 23 0
75% 0.5 W/m2K 2.5 W/m2K
70 21 23 23 10 10 CURRENT ENERGY TECHNO SCENARIO CONSCIOUS ERA
EQUIPMENT LOAD OCCUPANT LOAD LIGHTING LOAD
Fig7. Internal heat gain profiles for typical weekdays at present (left) and internal loads under current and future scenarios (right)
Space heating and cooling setpoints were re-adjusted for naturally ventilated cases in compliance with the EN 15251 (2007) adaptive thermal comfort band. For Case 4.3C, the cooling loads were reduced by up to 92% on the south-facing variants, Fig. 7. The south-facing offices were found to be free-running for 72% of the occupied time, Fig. 9. For other orientations, the free-running periods for Case C were 65%, 57% and 63% for east, west and north, respectively. Cross ventilation and night-time cooling (Case 4.3) resulted in the best performance for all orientations. This variant was taken as a base case for the mitigation of climate change effects and for future trends in office design. Two future scenarios, Energy Conscious (5.1: EC) and Techno Era (5.2: TE) were tested (Fig. 10). South-facing Case C was found to perform best with 684 hours out of comfort under the EC scenario and 454 hours under TE, over a total of 2610 occupied hours, Fig. 10. Figure 11 shows simulation results for future variants of a southfacing office on typical summer and winter days. As can be seen in the figure, higher future outdoor air temperatures will make night-time ventilation necessary for summer cooling. Windows were assumed to be kept mostly closed during daytime. In winter, the rise in outdoor temperature may not be sufficient to compensate for the lower internal heat gains of the energy conscious scenario (Fig. 11 - Case 5.1). Hence, this will continue to require additional heating input for occupant thermal comfort. On the other hand, the techno explosion scenario (Fig. 11 - Case 5.2C) was shown to lead to overheating problems potentially throughout the year. The naturally ventilated period might need to be extended over the whole year or the building design specification should be reassessed.
1-SIDED VENT
CROSS VENT
20oC NIGHT COOLING
NEW SET POINT
92%
37
3.4 16 3.9
4.3C 1016
2.9
24
24
37
4.3A 9 4.3B 9
4.2C
16 16
36 4.2A 13 23 4.2B 15
4.1C
4.1B
18 23 20 15 22
4.1A
27
3C
14
23 23 22
3B
3A
2C
2B
23 28 23 18 26
36
36
43
46
28oC
91%
43
4.3
4.2
3.5
22
33
4.3C 11 22
4.3A 10 4.3B 11
19 21 20
4.2C
4.2B
33
43
42 32 16
4.2A
4.1C
4.1B
4.1A
21
32 26 20 28
33
3C
20
29 30 30
3B
3A
29 25 33
2C
2B
2A
42
42
50 29
36
49
21
1C
86% 6.9
6.7
5.3
22
34
34 22 15
4.3C
4.3A 12 4.3B 14
23 22 25
4.2C
4.2B
44
44
44 33 19
4.2A
4.1C
4.1B
21
34
43 33 31
25
4.1A
38
3C
20
32 32 35
3B
2C 2C
3A
2B 2B
43
51 33 39 35 28 38
2A 2A
48
1C
21
45 38 31 43
4.3
22
4.5 85%
46 3.8
32
4.3C 11 22
4.3A 10 4.3B 11
19 21 21
4.2C
4.2B
16
4.2A
32
46
45 32
30
4.1C
4.1B
21
23
4.1A
3C
32 29
45
45
3B
3A
1C
29 23 31
25 31 30 20 31
36
1A
1B
25
34
22
C
1B
53
1A
18
C
B B
NIGHT SHUTTER
65
58
1B
1A
19
C
B
51
40
27
A
51
KWH/M2 I NORTH 70 60 50 40 30 20 10 0 35 31
1C 11
1A
46 38 31 43
41
28
A
KWH/M2 I WEST 70 60 50 40 30 20 10 0
27
SHADING
66
50
59
KWH/M2 I EAST 70 60 50 40 30 20 10 0
1B
18
30
39
49
C 9
B
A
15
25
43
57
KWH/M2 I SOUTH 70 60 50 40 30 20 10 0
52
OBSTRUCTION
BASE
A
30o
2A
HEATING LOAD COOLING LOAD
Fig.8 Heating and cooling load consumptions for Case A (Green), Case B (Pink), Case C (Blue) envelopes Source: OpenStudio & EnergyPlus % 100 4% 80 18% 60 24% 40 20 0 3C 4.1C 4.2C 4.3C NO VENT
72
68
50
64
61
45
26
NO VENT
% 100 80 3% 16% 60 16% 40 20 0 3B 4.1B 4.2B 4.3B 29
52
51
38
28
NO VENT
% 100 80 1% 60 13% 40 10% 20 0 3A 4.1A 4.2A 4.3A
3: 2 + NIGHT SHUTTER 4.1: 3 + 1 SIDED VENT. 4.2: 4.1 + CROSS VENT. 4.3: 4.2 + NIGHT COOLING
Fig.9 Percentage of occupied hours within comfort according to EN15251 Standard Category II for south facade Left for Case A, middle for Case B and right for Case C Source: EnergyPlus
A B C
A B C
5.2 TE
A B C
5.2 TE
5.1 EC
5.2 TE
A B C
5.1 EC
758 237 604 256 425 282
A B C
A B C
5.1 EC
NORTH
995 129 882 161 817 163
WEST 801 316 655 353 466 371
A B C
5.1 EC
974 110 839 159 753 156
921 37 807 67 618 66
EQUIPMENT LOAD: 12W/M2-> 6W/M2(5.1 EC) 12W/M2-> 22W/M2 (5.2 TE)
EAST
602 200 404 204 188 266
SOUTH
LIGHTING LOAD: 7W/M2 -> 4W/M2
1048 192 943 240 851 247
# OF HOURS 2610
719 255 534 284 351 303
DAY TIME OCCUPANCY: 80% -> 90%
A B C
5.2 TE
1K ABOVE COMFORT 1K BELOW COMFORT
FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH
Fig10. New inputs (left), number of hours out of comfort for 1K according to EN15251 Standard (right) Source: EnergyPlus W/m2 ACH I oC
ACH I oC 40
1000 40
W/m2 ACH I oC 1000 40
W/m2 ACH I oC 1000 35
W/m2 1000
875
35 SUMMER
875
35 SUMMER
875
30 WINTER
875
30
750
30
750
30
750
25
750
25
625
25
625
25
625
20
625
20
500
20
500
20
500
15
500
15
375
15
375
15
375
10
375
10
250
10
250
10
250
5
250
5
125
5
125
5
125
0
125
0
0
0
0
0
0
35 SUMMER
13 I 06
14 I 06
OUTDOOR TEMP. I OC CASE 5.1A: EC + 4.3A CASE 5.2A: TE + 4.3A CASE 5.1A INFILTRATION CASE 5.2A INFIL.
13 I 06
14 I 06
OUTDOOR TEMP. I OC CASE 5.1B: EC + 4.3B CASE 5.2B: TE + 4.3B CASE 5.1B INFIL. CASE 5.2B INFIL.
13 I 06
14 I 06
OUTDOOR TEMP. I OC CASE 5.1C: EC + 4.3C CASE 5.2C: TE + 4.3C CASE 5.1C INFIL. CASE 5.2C INFIL.
-5
04 I 12
05 I 12
0
OUTDOOR TEMP. I OC NIGHT SHUTTER ON CASE 5.1A: EC + 4.3A CASE 5.2A: TE + 4.3A CASE 5.1B: EC + 4.3B CASE 5.2B: TE + 4.3B CASE 5.1C: EC + 4.3C CASE 5.2C: TE + 4.3C
Fig11. Typical summer day (Case A, B, C respectively) and winter day (right) of a future south facing office Source: EnergyPlus
Conclusions The research summarized in this paper has shown the importance of window orientation in determining room depth and solar protection of workspaces in the climatic conditions of Ankara. Implementation of passive design measures can go a long way toward providing occupant thermal comfort for new office buildings. Conflicts between winter and summer performance tend to appear, but trade-offs can be found. The simulation studies showed that the atrium typology can provide better results for natural ventilation by exhausting warm air through the stack effect, and by creating a pleasant working environment for occupants. Occupant thermal comfort can be achieved for 72% of the time by the application of stack ventilation and night-time cooling on top of other passive strategies. Apart from the qualitative benefits, cooling loads can be reduced by up to 92% with a small penalty on heating loads. References
CIBSE. (1999). SLL Lighting guide 10: Daylighting and window design. The Chartered Institution of Building Services Engineers. London, UK. Durmaz, E. (2016). Daylight & Thermal Performance of Office Buildings in Ankara. Architectural Association School of Architecture, London, UK. EN15251. (2007). Indoor environmental input parameters for design and assessment of energy performance of buildings- addressing indoor air quality, thermal environment, lighting and acoustics. CEN, Brussels. Johnston, J., Counsell, J., & Strachan, P. A. (2011). Trends in office internal gains and the impact on space heating and cooling. CIBSE Technical Symposium. Leicester, UK: 06-07 September 2011. Meteotest (2015). Meteonorm version 7. Turk Standartlari Enstitusu (Turkish Standards Institution). (2008). Binalarda isi yalitim kurallari (Thermal insulation requirements for buildings), TS 825. Ankara, TSE (in Turkish). TurkStat (Turkish Statistical Institute). Building permits statistics. Retrieved August 25, 2016, from http:// www.turkstat.gov.tr (in Turkish).