• Numerical Analysis of a Wind Catcher Assisted Passive Cooling Technology

      Calautit, John Kaiser; Hughes, Ben; Shahzad, Sally; Nasir, Diana S. N. M.; University of Sheffield; University of Derby (USES 2015 - The University of Sheffield Engineering Symposium, 2015)
      Buildings are responsible for almost 40% of the world energy usage. Heating Ventilation and Air-Conditioning (HVAC) systems consume more than 60% of the total energy use of buildings. Clearly any technology that reduces HVAC consumption will have a dramatic effect on the energy performance of the building. Natural ventilation offers the opportunity to eliminate the mechanical requirements of HVAC systems by using the natural driving forces of external wind and buoyancy effect. One technology, which incorporates both wind and buoyancy driven forces, is the wind catcher. Wind catchers are natural ventilation systems based on the design of traditional architecture. Though the movement of air caused by the wind catcher will lead to a cooling sensation for occupants, the high air temperature in hot climates will result in little cooling to occupants. In order to maximise the properties of cooling by wind catchers, heat transfer devices were incorporated into the design to reduce the supply air temperature. The aim of this work was to investigate the performance of a wind catcher integrated with heat transfer devices using numerical modelling and wind tunnel experiment. The wind catcher model was incorporated to a building, representing a small room of 15 people. Care was taken to generate a high-quality CFD grid and specify consistent boundary conditions. An experimental model was created using 3D printing and tested in a wind tunnel. Qualitative and quantitative wind tunnel measurements were compared with the CFD data and good correlation was observed. The study highlighted the potential of the proposed wind catcher in reducing the air temperature by up to 12 K and supplying the required fresh air rates.
    • Numerical Analysis of a Wind Catcher Assisted Passive Cooling Technology.

      Calautit, John Kaiser; Hughes, Ben; Shahzad, Sally; Nasir, Diana S. N. M.; University of Sheffield; University of Derby (USES 2015 - The University of Sheffield Engineering Symposium, 2015)
      Buildings are responsible for almost 40% of the world energy usage. Heating Ventilation and Air-Conditioning (HVAC) systems consume more than 60% of the total energy use of buildings. Clearly any technology that reduces HVAC consumption will have a dramatic effect on the energy performance of the building. Natural ventilation offers the opportunity to eliminate the mechanical requirements of HVAC systems by using the natural driving forces of external wind and buoyancy effect. One technology, which incorporates both wind and buoyancy driven forces, is the wind catcher. Wind catchers are natural ventilation systems based on the design of traditional architecture. Though the movement of air caused by the wind catcher will lead to a cooling sensation for occupants, the high air temperature in hot climates will result in little cooling to occupants. In order to maximise the properties of cooling by wind catchers, heat transfer devices were incorporated into the design to reduce the supply air temperature. The aim of this work was to investigate the performance of a wind catcher integrated with heat transfer devices using numerical modelling and wind tunnel experiment. The wind catcher model was incorporated to a building, representing a small room of 15 people. Care was taken to generate a high-quality CFD grid and specify consistent boundary conditions. An experimental model was created using 3D printing and tested in a wind tunnel. Qualitative and quantitative wind tunnel measurements were compared with the CFD data and good correlation was observed. The study highlighted the potential of the proposed wind catcher in reducing the air temperature by up to 12 K and supplying the required fresh air rates.
    • Thermal comfort and indoor air quality analysis of a low-energy cooling windcatcher.

      Calautit, John Kaiser; Aquino, Angelo I.; Shahzad, Sally; Nasir, Diana S. N. M; Hughes, Ben Richard; University of Sheffield; University of Derby (Applied Energy, 2016)
      The aim of this work was to investigate the performance of a roof-mounted cooling windcatcher integrated with heat pipes using Computational Fluid Dynamics (CFD) and field test analysis. The windcatcher model was incorporated to a 5m x 5m x3 m test room model. The study employed the CFD code FLUENT 15 with the standard k-ɛ model to conduct the steady-state RANS simulation. The numerical model provided detailed analysis of the airflow and temperature distribution inside the test room. The CO2 concentration analysis showed that the system was capable of delivering fresh air inside the space and lowering the CO2 levels. The thermal comfort was calculated using the Predicted Mean Vote (PMV) method. The PMV values ranged between +0.48 to +0.99 and the average was +0.85 (slightly warm). Field test measurements were carried out in the Ras-Al-Khaimah (RAK), UAE during the month of September. Numerical model was validated using experimental data and good agreement was observed between both methods of analysis.