Figure 1
Flow chart showing the steps applied in the research method.
Figure 2
Floor plan for the two-bedroom apartment case study.
Note: Dimensions = mm.
Table 1
Building envelope properties.
| BAU ENVELOPE PROPERTIES | ECBC ENVELOPE PROPERTIES | |
|---|---|---|
| Wall | 18 mm cement plaster (inner most) 230 mm uninsulated brick wall 18 mm cement plaster (outer most) U-value: 1.722 W/m2K | 18 mm cement plaster (inner most) 230 mm uninsulated brick wall with XPS insulation 18 mm cement plaster (outer most) brick wall U-value: 0.44 W/m2K |
| Roof/floor | 12 mm cement plaster (inner most) 150 mm concrete roof 12 mm tiles (outer most) U-value: 2.942 W/m2K | 12 mm cement plaster (inner most) 150 mm concrete roof with XPS insulation 12 mm tiles (outer most) U-value: 0.409 W/m2K |
| Window | 6 mm single-glazed anodised aluminium frame without thermal breaks U-value: 5.8 W/m2K | Double-glazed windows with thermal break U-value: 3.3 W/m2K |
Table 2
Summary of the different ventilation and cooling scenarios and systems per space.
| APARTMENT SPACE | WINDOWS | DAMPERS | CEILING FAN | MECHANICAL COOLING–AC SPLIT UNIT | DEHUMIDIFIER | MECHANICAL VENTILATION |
|---|---|---|---|---|---|---|
| Available systems per space | ||||||
| Living room | Yes | Yes | Yes | Yes | Yes | Yes |
| Master bedroom | Yes | Yes | Yes | Yes | No | No |
| Small bedroom | Yes | Yes | Yes | Yes | No | No |
| Available systems per ventilation and cooling strategy | ||||||
| Base case (fully AC mode) | Not provided | Not provided | Not provided | Provided | Not provided | Not provided |
| VCS 1 | Provided | Not provided | Not provided | Provided | Not provided | Not provided |
| VCS 2 | Provided | Provided | Not provided | Provided | Not provided | Not provided |
| VCS 3 | Provided | Provided | Provided | Provided | Not provided | Not provided |
| VCS 4 | Provided | Provided | Provided | Provided | Provided | Provided |
[i] Note: AC = air-conditioning; VCS = ventilation and cooling control strategy.
Figure 3
Master control algorithm.
Figure 4
Variable exchange between the EnergyPlus and Dymola simulation tools.
Table 3
Scenarios examined for the validation study.
| SCENARIO | DATE | TIME (HOURS) | Tout (°C) | Tinternal (°C) 1 H BEFORE THE EXPERIMENT | WINDOW OPENING AREA (m2) | DAMPER NV1 OPENING AREA (m2) | DAMPER NV2 OPENING AREA (m2) | ASSUMED AIR VELOCITY (m/s) | TOTAL INTERNAL HEAT LOAD (W) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 July | 23.00–00.00 | 29.3 | 31.3 | 0.440 | 0.171 | 0.173 | 0.6 | 305 |
| 2 | 4 August | 08.00–09.00 | 27.4 | 27.9 | 0.501 | 0.183 | 0.184 | 0.0 | 216 |
| 3 | 11 March | 21.00–22.00 | 27.3 | 29.4 | 0.416 | 0.170 | 0.173 | 0.9 | 324 |
| 4 | 14 May | 03.00–04.00 | 27.3 | 29.4 | 0.398 | 0.170 | 0.172 | 0.0 | 262 |
| 5 | 5 December | 00.00–01.00 | 20.5 | 25.0 | 0.281 | 0.150 | 0.155 | 0.0 | 285 |
| 6 | 16 August | 02.00–03.00 | 26.3 | 29.7 | 0.315 | 0.156 | 0.159 | 1.2 | 322 |
| 7 | 6 November | 22.00–23.00 | 23.8 | 30.2 | 0.0 | 0.092 | 0.102 | 1.2 | 322 |
| 8 | 31 January | 07.00–08.00 | 18.3 | 23.2 | 0.0 | 0.133 | 0.133 | 0.0 | 267 |
| 9 | 7 August | 06.00–07.00 | 25.6 | 30.7 | 0.0 | 0.133 | 0.139 | 0.6 | 326 |
[i] Note: NV = natural ventilation.
Table 4
Construction materials and thermal properties of the experimental chamber.
| MATERIAL | CONDUCTIVITY (W/(mK)) | SPECIFIC HEAT (J/(kgK)) | DENSITY (kg/m3) |
|---|---|---|---|
| Kota stone | 3.02 | 668 | 3102 |
| Sand mortar | 0.88 | 896 | 2800 |
| Plain cement concrete | 0.72 | 840 | 1860 |
| Cement putty | 0.114 | 742 | 1070 |
| Plaster (dense) | 0.50 | 1000 | 1300 |
| AAC block | 0.35 | 1100 | 780 |
| Insulation (XPS) | 0.029 | 1525 | 37 |
| RCC (2% steel) | 2.50 | 1000 | 2400 |
| Cement mortar | 0.720 | 920 | 1650 |
| Ceramic tiles flooring | 0.920 | 820 | 1950 |
| Acrylic paint | 0.201 | 1342 | 745 |
[i] Note: AAC = autoclaved aerated concrete; RCC = reinforced cement concrete; XPS = extruded polystyrene.
Figure 5
Sensor location in the experimental chamber.
Table 5
Sensors used for the experiments and their accuracy.
| INSTRUMENT | PARAMETER MEASURED | QUANTITY | ACCURACY | |
|---|---|---|---|---|
| Testo 480 climate measurement instrument | Globe thermometer | Globe temperature (°C) | 1 | ±1.5°C between –40 and 375°C |
| IAQ probe | CO2 (ppm) | 1 | ±(75 ppm + 3% of the mean) | |
| Turbulence probe | Air velocity (m/s) | 1 | ±(0.03 m/s + 4% of the mean) | |
| PT100 RTD | Air temperature (°C) | 12 | ±0.15°C | |
| Surface temperature (°C) | 7 | ±0.15°C | ||
| CO2 sensor | CO2 concentration (ppm) | 2 | ±30 ppm + 3% of reading | |
| IAQ sensor | CO2 concentration (ppm) | 2 | 50 ppm ± 3% | |
[i] Note: IAQ = indoor air quality; ppm = parts per million; RTD = resistance temperature detector.
Figure 6
Flow chart for the set-up of the physical experiments performed in the environmental chamber.
Figure 7
Comparison of the experimental and simulated models.
Note: Error bars highlight the uncertainties during the experiments.
Table 6
Total number of hours of natural ventilation (NV) and comfort hours for all cities when split air-conditioning (AC) units were used as the cooling systems.
| CITY | AHMEDABAD | BANGALORE | CHENNAI | DELHI | ||||
|---|---|---|---|---|---|---|---|---|
| Window operation with up to 20% night-time restriction or none | Restrict | None | Restrict | None | Restrict | None | Restrict | None |
| VCS 1 (without ceiling fan) | ||||||||
| Comfort hours (h) | 1287 | 1557 | 2788 | 2977 | 948 | 1458 | 986 | 1247 |
| NV hours (h) | 2247 | 2398 | 4673 | 4879 | 1797 | 2647 | 1876 | 2247 |
| Comfort hours/(NV hours) (%) | 57% | 65% | 60% | 61% | 53% | 55% | 53% | 56% |
| VCS 2 (without ceiling fan) | ||||||||
| Comfort hours (h) | 1758 | 2018 | 3578 | 3987 | 1267 | 1787 | 1685 | 1934 |
| NV hours (h) | 2378 | 2680 | 4757 | 5087 | 2058 | 2700 | 2230 | 2487 |
| Comfort hours/(NV hours) (%) | 74% | 75% | 75% | 78% | 62% | 66% | 76% | 78% |
| VCS 3 (with ceiling fan) | ||||||||
| Comfort hours (h) | 2457 | 2788 | 4673 | 5304 | 2449 | 2946 | 1968 | 2315 |
| NV hours (h) | 2745 | 3058 | 5087 | 5677 | 3126 | 3575 | 2384 | 2679 |
| Comfort hours/(NV hours) (%) | 90% | 91% | 92% | 93% | 78% | 82% | 83% | 86% |
| VCS 4 (with ceiling fan) | ||||||||
| Comfort hours (h) | 1977 | 2249 | 3973 | 4079 | 2143 | 2317 | 1578 | 1789 |
| NV hours (h) | 2687 | 2788 | 4869 | 4939 | 2887 | 2967 | 2047 | 2177 |
| Comfort hours/(NV hours) (%) | 74% | 81% | 82% | 83% | 74% | 78% | 77% | 82% |
[i] Note: VCS = ventilation and cooling control strategy.
Figure 8
Energy-saving potential for the different ventilation and cooling strategies applied to (a) Ahmedabad, (b) Bangalore, (c) Chennai and (d) Delhi.