Natural Ventilation: 1

- Envelope:
- Envelope flows:
- Internal flows:
- Natural ventilation:
- Prupose-provided openings:
- Advantaous openings:
- Infiltration:
- Exflitartion:

List the hierarchy of ventilation systems:

What should you you do before using mechanical solutions?

Advantages of natural ventilation:

Disadvantages of natural ventilation:

Design process diagram

Feasibility points:

Climate:

- Steady state conditions
- Transient weather file

Climate:

Data sources?

Climate:

What has to be done for climate weather data?

Climate:

Modified wind speed

Climate:

Modified wind speed equation

Internal heat gains:

Preventing over heating strategies

Internal heat gains:

Why are occupants important?

Building geometry and environment:

What creates pressure distribution around a building?

Building geometry and environment:

What is Pgauge equal to?

Building geometry and environment:

- What is the wind pressure coefficient?
- How can wind pressure babe measured?
- Alternatively?
- What about for simulations?

Building geometry and environment:

Diagram of regional boundary layers?
Diagram of isolated roughness flow?
What is a bu8ilding of isolated roughness effected by?

Building geometry and environment:

Diagram of building wakes
What can wakes do?

Building plan and layout:

Wakes induced by different forms.
The first is:

Building plan and layout:

Wakes induced by different forms.
The second is:

Building plan and layout:

Effect of incidence angle of internal flow (1 of 2):

Building plan and layout:

Augmenting positive pressure and internal air velocity using Wingwalls diagram

Building plan and layout:

- In deep plan buildings, what are the issues and how can they be resolved?

Building plan and layout:

Side sided room diagram

Building plan and layout:

Single sided double opening layout

Building plan and layout:

Cross ventilation room diagram

Building plan and layout:

Clerestory room diagram

Building plan and layout:

Stack

Building plan and layout:

Can high rises be naturally ventilated? How?

Building envelope:

Why is it one of the most important factors?

Building envelope:

What is adventitious leakage?

Building envelope:

What else occurs through the envelope apart from adventitious leakage?

Thermal storage:

Requirements

Thermal storage:

Diagram of thermal mass on peak indoor temperature

Control:

- By design
- By mechanical devices

Control:

- Other options

What does the term strategy refer to?

What are the 2 basic categories of internal space?

Isolated spaces - What are the 2 basic types?

Connected spaces: single cell building:

- Atrium/tower

Connected spaces: single cell building:

- Chimney
- Duct walls
- Wind catcher

Connected spaces: single cell building:

- Top down ventilation

Descriptions of Mechanisms:

Ventilation of a building can be considered as comprising two processes :–

Descriptions of Mechanisms:

What are the 3 cases?

Diagram of buoyancy alone (no wind)

Buoyancy alone (no wind):

- Envelope flow

- Internal air motion

Wind alone (uniform density) diagram

Wind alone (uniform density):

- Envelope flow

- Internal air motion

Wind and buoyancy combined:

- Graph
- In general...

Airflow through openings:

- Equation for discharge coeffiecnt

- Fundamental problems

3 basic mathematical models?

Sizing of openings:

What is the aim for a chosen strategy?

Why would we use the envelope flow model?

Sizing of openings:

Basic procedure

Design conditions:

- Climate with 2 seasons
- What does the explicit method determine?

Design conditions:

In winter what must we ensure?
What is the basic procedure?

Design conditions:

In winter, what is the 'worst case'?

Design conditions:

In winter, using the explicit method (iii) what must we use? Why not windows?

Design conditions:

In summer, what must be prevented?
What is the basic procedure?

Design conditions:

Rate of internal heat gains equation

Later design processes:

- What conditions are used?
- What types of tools are available?

Computational fluid dynamics:

Diagram

Computational fluid dynamics:

What are the most versatile design tools?

What are the uncertainities with CDF (computioanl fluid mechanics)?

Combined thermal and airflow models:

- What is a major difficulty in design?
- Are combinations available?

Combined thermal and airflow models:

- Do you use 2 models together?
- What is a more simple way?
- What is an issue?

What can you conclude from this topic?