School of Civil Engineering Integrating Heat Transfer Devices Into Wind Tower Systems to provide...

School of Civil Engineering

Integrating Heat Transfer Devices Into Wind Tower Systems to provide Thermal Comfort in Residential Buildings

John Kaiser S. CalautitSupervisors: Dr. B. Hughes and Prof. N. Wright3rd CFD Group Meeting


John Kaiser S. Calautit

Wind Tower – Natural Ventilation Device

Stale Air Out

Fresh Air In

(Micro Climate)

- Leeward

+ Windward

(Macro Climate)((

(Macro Climate)((

• • Originated from the Middle East (hot and arid regions).

• Incorporated with advance technology (control dampers, ceiling diffusers , solar panels)

Traditional Architecture Commercialized Re-Engineering

• Bring the technology back to the Middle East using heat transfer devices powered system.

Buoyancy and displacement effect (driving forces)

Windward (+) Leeward (-)


Looking into Wind Tower Systems – Airflow Analysis

• Supplies airflow at ceiling level

• Increased the indoor airflow by up to 60%

• Two 4-sided wind tower system (2 floor residential building)

• Average indoor airflow of 0.4 m/s



Traditional Evaporative Cooling (Controlled Test): Existing Cooling Technology

0 1 2 3 4 5 6 7 8 9 10293295297299301303305307309311

Evaporative cooling

Position (m)

Stat

ic T

empe

ratu

re (k

)

Disadvantages:

1. Water - scarce

2. Pump – continuous power supply

3. High Tower – not feasible in urban areas

297 K

Wind Tower Channel with Evaporative Cooling (Published Data)

310K

297 K


Inlet310K

Outlet

Injected Water 0.05 kg/s, 293K



Top Hat

Adjustable Dampers

Louver

1. Integrate heat transfer devices into a commercial wind tower system for the Middle East.

Aims and Objective:

Evaporator

Condenser

Heat exchanger system



2. Optimize the thermal comfort of a Qatari residence using the proposed wind tower system. Predicting thermal comfort using PMV model software.

0 5 10 15 20 2505

1015202530354045

Summer - June

InsideOutside

Time (Hour)

Tem

per

atu

re (

C°)

35 C°

Predict Thermal Comfort

•Required Indoor Temperature?•Required Indoor Velocity?

Hottest Month



Challenges:

1. Reduce the indoor temperature by 10-12K to achieve thermal comfort during summer periods.

2. Achieve minimal restriction in the external air flow stream while ensuring maximum contact time. Supply up to 400 L/s

3. Compact Design - Fit the heat transfer devices and cool sink inside wind tower.

4. Cool Sink

5. Dust



CFD Results : Airflow Analysis – Louver Angle (Components)

2.55 m/s

3.31m/s

45˚ 35˚

Reduced Air CirculationHigh Air Circulation

1 m/s 1 m/sUnavoidable due to the louvers and 90˚ bend



Research Output: Publications

• B R Hughes, J K Calautit, S A Ghani, The development of commercial wind towers for natural ventilation: A review, Applied Energy, 92, 606-627, 2012

• J K Calautit, B R Hughes, S A Ghani, A Numerical Investigation into the Feasibility of Integrating Green Building Technologies into Row Houses in the Middle East, Architectural Science Review, 55, 1-18, 2012.

Future Work:

• CFD (Transient Modeling, UDF, Solar Loading, Dynamic Mesh)

• Experimental Work (Wind Tunnel Design, Scaled-Model Testing)

• Qatar Visit (Duct Testing and Full Scale Testing)

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