Performance analysis of a schoolroom model for solar applications


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Iskandar Makhmudov (Jeju National University)
SET2009 - 8th International Conference on Sustainable Energy Technologies, Aachen, Germany.

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Performance analysis of a schoolroom model for solar applications

  1. 1. SET2009 - 8th International Conference on Sustainable Energy Technologies, .Aachen, Germany. August 31st to 3rd September 2009 Page 1 of 4 Performance analysis of a schoolroom model for solar applications Iskandar Makhmudov1, Hyunjoo Han2, Young Il Jeon2, Sang Hoon Lim3, Wongee Chun1 1 Department of Nuclear & Energy Engineering Department, Jeju National University, Jeju, 690-756, Korea 2 Division of Architecture, Dongguk University, Seoul, 100-715, Korea 3 New & Renewable Energy Research Division, Korea Institute of Energy Research, Taejeon, 305-343, Korea ABSTRACT: The thermal and indoor daylighting behaviour of a schoolroom was investigated by using a numerical model whose reliability was experimentally examined. The schoolroom model, constructed using the modern simulation tool, has a number of south-oriented windows under which black iron plates are installed to induce thermosyphoning with arrays of upper and lower vents. A hallway is considered to cause 0.35 air changes per hour for zones by natural ventilation. For thermal analysis, simulations were carried out using the standard weather conditions and physical properties of real materials. Perfect thermal insulation was assumed for the ceiling, floor and walls between adjoining schoolrooms. Results showed that the simulation model of the present work, although simple, is accurate enough to predict the building’s thermal performance. Especially, in the early stages of designing, the results could be effectively applied to assess various aspects of design parameters in real cases without undue difficulties. Keywords: Thermal analysis, Simulation, Daylighting, Schoolroom 1. INTRODUCTION windows. The configuration of schoolroom design, which contains certain distinctive Passive solar heating technologies can characteristics in trapping and utilization of offer a wide range of benefits for buildings solar energy, was proposed by the Ministry and our deteriorating environment by of Education in Korea (once considered as reducing energy consumption and carbon the standard passive solar schoolroom). The emissions. Considering the geographical configuration adopts the two-zone system location of Korea, passive solar schemes with black iron plates for quick absorption could be efficiently (and economically) and release of solar energy. The thermal applied to public and residential buildings performance of the schoolroom during for space heating and daylighting. winter time will be presented in this study. This paper reports the design, simulation and in-site measurement results of a prototype schoolroom with some passive solar features other than large south-facing
  2. 2. SET2009 - 8th International Conference on Sustainable Energy Technologies. Aachen, Germany 31st August to 3rd September 2009 Page 2 of 4 2. MODEL SCHOOLROOM The configuration of the schoolroom model (Fig.1) consists of two parts (zones): a schoolroom with 7.5m (length) x 9m (width) x 3.3m (height) and hallway with 2.7m x 9m x 3.3m. The schoolroom has large south facing windows whereas the hallway locates relatively small windows on the north side of the wall. The walls, ceiling and floor of the schoolroom are made of concrete and heavily insulated. Figure 2: Schematic view of the schoolroom south-facing area. Thermosyphoning could be induced by Figure 1: Schematic view of the opening the upper and lower vents which schoolroom model. allows continuous flow of hot air into the schoolroom during heating periods. In The south-facing area of the schoolroom summer, overhang prevents the indoor is comprised of two sections (Fig.2). The temperature from overheating and cross- upper half consists of two layers of operable ventilation is induced by opening the windows for direct gains, while the lower windows in the opposite (north) side of the half is characterized by a non-operable schoolroom. glazing followed by a black iron plate for Weather conditions were taken from the quick absorption and emission of solar weather database [1] of the U.S. Department energy. The black iron plate is covered with of Energy for Seoul, Korea. The interzonal 3mm single glass layer for protection from air flow between the schoolroom and environment impacts. As the sun’s rays pass hallway is assumed to be 0.35 air changes through the outer glazing and hit the surface per hour. This accounts for the occasional of black plate, this immediately raises its opening of the door during intermissions. temperature and in turn heats the air trapped Most of the heat flow between the zones is within glazing and the iron plate. through the partition wall that separates the schoolroom and hallway. Each schoolroom is occupied with 50 students. Classes are held from 9 a.m. to 5 p.m.
  3. 3. SET2009 - 8th International Conference on Sustainable Energy Technologies. Aachen, Germany 31st August to 3rd September 2009 Page 3 of 4 3. RESULTS AND DISCUSSION complexity of the schoolroom model in the present analysis. Thermal analysis was done by To measure the effect of solar lighting for ECOTECT and its results were compared the schoolroom, photometric analysis was with previous simulation results of also carried out (Tab. 2). Nine photosensors SUNCODE (Tab. 1). In general, ECOTECT were placed on the western wall (where a values [2, 3, 4] fluctuated from 6.0 C to 9.6 chalkboard is situated) horizontally and C and SUNCODE values showed a range vertically at a regular interval of 45cm. The of 5.9 - 8.2 C. The highest values were illuminance values shown in Table 2 are observed at 1 p.m. in both cases. those recorded at 12:30 p.m. under an overcast sky condition in Seoul (37.5° N and Table 1: Temperature comparison between 126.9° E). Simulations were also carried out SUNCODE and ECOTECT(C). for daylighting using RADIANCE whose ___________________________________ accuracy has long been established by many Hour ECOTECT SUNCODE Temp. Diff. previous studies. ___________________________________ 00 6.2 6.3 0.1 Table 2: Illuminance value compared at 01 6.2 6.4 0.2 different locations between the measured 02 6.2 6.3 0.1 and simulation (lux). 03 6.2 6.2 0.0 __________________________________ 04 6.2 6.1 0.1 Sensor Simulation Measured 05 6.2 6.1 0.1 __________________________________ 06 6.2 6.0 0.2 1 421.6 421 07 6.3 5.9 0.4 2 470.9 414 08 6.4 5.9 0.5 3 468.0 434 09 9.3 6.4 2.9 4 323.5 343 10 9.4 6.5 2.9 5 350.0 350 11 9.4 7.2 2.2 6 360.3 359 12 9.4 8.0 1.4 7 254.6 254 13 9.6 8.2 1.4 8 274.1 265 14 9.4 8.0 1.4 9 271.8 271 15 9.2 8.0 1.2 _________________________________ 16 9.2 8.1 1.1 17 9.0 7.8 1.2 From this table, we could see two agrees 18 6.2 7.5 1.3 quite well despite measurement 19 6.1 7.1 1.0 uncertainties and other unknown factors that 20 6.1 7.0 0.9 could have influenced otherwise. 21 6.0 6.8 0.8 22 6.0 6.5 0.5 23 6.0 6.3 0.3 5. CONCLUSION ___________________________________ In the present study, the typical passive Temperatures varied proportionate to the schoolroom model was investigated for its intensity of solar radiation, which changes indoor thermal and daylighting performance throughout the day. A maximum using different computational tools. For temperature difference of 2.9 C was thermal analysis, ECOTECT was brought in observed in two cases which deems whose results were compared with those of relatively reasonable considering the SUNCODE. Meanwhile, its indoor daylighting performance was examined
  4. 4. SET2009 - 8th International Conference on Sustainable Energy Technologies. Aachen, Germany 31st August to 3rd September 2009 Page 4 of 4 using RADIANCE and then compared with some measured values. It is felt that the procedures taken for thermal and lighting analyses in the present study could be further extended for other types of solar buildings (systems) to elicit the most feasible design in reality for maximum efficiency in utilizing the sun’s energy. ACKNOWLEDGEMENT This work was supported by the grant (No. 2009-0075776) from the Korea Science & Engineering Foundation. REFERENCES [1]Weather database of the U.S. Department of Energy: [2]S.H. Lim, N.H. Lee, and B.K. Lim, 1991. A performance study on Direct Gain Passive Solar School Buildings. Journal of Solar Energy Society of Korea, Vol. 11. No. 3. pp.37-43. Korea. [3]Norbert Lechner, 2000. Heating, Cooling, Lighting: Design Methods for Architects (2nd edition). [4] H. Han, A comparative study on the thermal performance of passive solar schoolroom, MS Thesis, Chungnam Nat’l University, Korea, 1991. [5]G. Makaka, E.L.Meyer, M. McPherson, 2008. Thermal behaviour and ventilation efficiency of a low-cost passive solar energy efficient house. Renewable Energy, Vol. 33. Issue 9. pp. 1959-1973. [6]D.B. Crawley, J.W. Hand, M. Kummert, B.T. Griffith, 2008. Contrasting the capabilities of building energy performance simulation programs. Building and Environment, Volume 43. Issue 4. pp. 661-673. [7]C. Reinhart, A. Fitz, 2006. Findings from a survey on the current use of daylight simulations in building design. Energy and Buildings. Volume 38. Issue 7. pp. 824-835.