Solar Chimney Ventilation Model

Buildings in hot climates spend a large share of their energy on mechanical ventilation and cooling, yet one of the oldest ventilation principles needs no electricity at all: heat air, let it rise through a tall stack, and fresh air is pulled in to replace it. A solar chimney turns this stack effect into a building system — a glazed solar collector heats air, a tall chimney amplifies the buoyancy draft, and the building ventilates itself whenever the sun shines. This project models that system on a bench-top rig: a glass-covered collector box with a black absorber plate, a vertical chimney stack, inlet vents, and a full sensor set (temperatures at inlet, collector and chimney, airflow velocity at the outlet) feeding an Arduino data logger. Students can vary collector area, chimney height and irradiance, and watch the ventilation rate respond — the core relationship every solar-chimney paper is built on.

1. Sunlight — or the sun-simulator lamps for indoor demos — passes through the glazing and heats the black absorber plate.
2. Air inside the collector box warms, becomes less dense and begins to rise into the chimney stack.
3. The tall stack amplifies the buoyancy pressure difference, accelerating the upward flow.
4. Rising hot air exits at the chimney top while cooler ambient air is drawn in through the inlet vents, creating continuous passive ventilation.
5. DS18B20 sensors log temperatures at the inlet, collector and chimney; the anemometer measures outlet velocity.
6. The Arduino displays live readings and exports timestamped CSV data so students can plot ventilation rate against irradiance and temperature difference.

Tech stack:

• Glazed collector box with black absorber plate
• Vertical chimney stack (approx. 1 m, scaled model)
• DS18B20 digital temperature sensors (inlet, collector, chimney)
• Anemometer for outlet airflow velocity
• IR/heat sun-simulator lamps
• Arduino data logger with LCD and serial CSV export

• [Glazed solar collector] A glass-covered box over a black absorber plate traps solar heat, raising the air temperature that drives the draft.
• [Tall chimney stack] A vertical stack of approximately one metre amplifies the buoyancy pressure difference between inlet and outlet.
• [Multi-point temperature logging] DS18B20 sensors record air temperature at the inlet, inside the collector and along the chimney.
• [Outlet airflow measurement] An anemometer at the chimney top measures the ventilation velocity the stack effect produces.
• [Sun-simulator lamps] Heat lamps stand in for the sun so the model demonstrates indoors regardless of weather or time of day.
• [Arduino data logger] An Arduino logs temperatures and airflow to an LCD readout and exports timestamped CSV over serial for analysis.
• [Optional turbine power demo] A small turbine-generator at the chimney outlet can be added as a customization to demonstrate solar-updraft power generation.

• Working solar chimney model with collector, stack and sensor instrumentation
• Arduino data-logger firmware source
• Fabrication drawings, wiring documentation, component list
• Experiment procedure (varying irradiance, chimney height, collector area)
• Project report PDF (stack-effect theory, heat-transfer analysis, experiment results format)
• PPT presentation for final review
• Viva Q&A preparation document (buoyancy, stack effect, solar thermal basics)
• Setup guide

• This is a scaled model — real solar chimneys are tens of metres tall, so absolute airflow values do not transfer directly to buildings; the model demonstrates the relationships, not full-scale performance.
• Airflow depends strongly on actual irradiance and ambient conditions; indoor lamp demonstrations only approximate the solar spectrum.
• All performance figures are design targets — students record their own temperature and airflow data during the experiments, and no results are pre-claimed.
• The base build is a passive ventilation demonstrator; active controls (dampers, night flushing logic) are possible customizations.
• The absorber and glazing need periodic cleaning for repeatable readings, as dust changes the heat absorption.