Ventilation and Airflow in Buildings
Höfundur:
Claude-Alain Roulet (Útgáfa: 1)
Kaup valmöguleikar
Energy efficiency in buildings requires, among other things, that ventilation be appropriately dimensioned: too much ventilation wastes energy, and insufficient ventilation leads to poor indoor air quality and low comfort. Studies have shown that ventilation systems seldom function according to their commissioned design. They have also shown that airflow measurement results are essential in improving a ventilation system.
This key handbook explains why ventilation in buildings should be measured and describes how to measure it, giving applied examples for each measurement method. The book will help building physicists and ventilation engineers to properly commission ventilation systems and appropriately diagnose ventilation problems throughout the life of a building. Drawing on over 20 years of experience and the results of recent international research projects, this is the definitive guide to diagnosing airflow patterns within buildings.
Nánar um bókina
- Taylor & Francis
- 9781136549083
- 9781138986695
- ePub
- 1
- Claude-Alain Roulet
- English
- 2012-05-16
- 100
- 2
- 2
Kaflar
- Cover Page
- Half Title page
- Title Page
- Copyright Page
- Contents
- List of Figures and Tables
- Preamble
- Introduction
- 1 Airflow Rates in Buildings
- Single-zone measurements
- Mass conservation of tracer gas and air
- Tracer decay, no injection
- Constant injection rate
- Constant concentration
- Pulse injection
- Simple and cheap air change rate measurement using CO2 concentration decays
- Method
- Equivalent outdoor airflow rate
- Equivalent outdoor airflow rate per person
- Example of application
- Application to buildings, multi-zone
- Conservation of the masses of air and tracer gas
- Global system of equations
- Zone by zone systems of equations
- Further interpretation of the flow matrix
- Properties of the flow matrix
- Transfer of contaminants between zones
- Age matrix and mean age of air
- Equations for volume flow rates
- Summary of the various tracer gas methods
- 2 Airflow Rates in Air Handling Units
- Measurement of the airflow rate in a duct
- Summary of measurement methods
- Orifice plate, nozzle and Venturi flowmeters
- Velocity traverse
- Equipment to measure air speed
- Test procedure
- Tracer gas dilution
- Airflow measurements at ventilation grilles
- Inflatable bag
- Flowmeter
- Compensated flowmeter
- Airflow rate measurements in air handling units
- Tracer gas injection ports
- Sampling points for concentration measurements
- Principle of the interpretation procedure
- Node by node method
- General method for ‘black box' air handling unit
- Building the system of equations
- Least square solution
- Eliminating some equations
- Looking for the best conditioned system
- Simplest way
- Less than four tracer gases
- Planning tool
- Example of application
- Simple measurement using CO2 from occupants
- Measurements in buildings with large time constants
- Appropriate method for assessing the recirculation ratio
- 3 Age of Air and Ventilation Efficiency
- Definitions
- Age of the air
- Nominal time constant
- Air exchange efficiency
- Measurement method
- Practical interpretation of the concentration records
- Error analysis
- Example of application
- Mapping the age of the air in rooms
- Minimum number of measurements
- Location of the measurement points
- Criteria for location of the measurement points
- The model matrix M
- Variance of the calculated response
- Condition of the model matrix
- Expendability of the experimental design
- Examples of experimental designs
- Factorial designs
- 3-D designs
- Example of application
- 4 Airtightness
- Why check airtightness?
- Measurement methods
- The fan pressurization method
- Reductive sealing
- Multi-zone fan pressurization method
- Determining the leakage coefficients
- Density corrections
- Two measurement points
- More than two measurement points
- Corrections for standard conditions
- Ways of expressing the airtightness
- Airflow rate at conventional pressure
- Virtual air change rate
- Specific leakage rate
- Equivalent leakage area
- Specific equivalent leakage area
- Airtightness of buildings
- External fan
- Internal fan
- Leakage visualization
- The stack effect method
- Neutral height method
- Measurement of airtightness of a duct or network
- Pressurization method
- Flow rate difference method
- Differential building pressurization
- 5 Measurements and Measures Related to Energy Efficiency in Ventilation
- Energy in buildings
- Energy uses and indoor environment quality
- Passive and active ways to get high quality buildings.
- Energy in air handling units
- Energy for heating and cooling buildings
- Energy for air conditioning
- Measurement of energy for heating, cooling, humidifying or dehumidifying air
- Heat exchangers
- Types of heat exchangers
- Rotating heat exchangers
- Glycol heat exchanger
- Heat pump
- Heat exchange efficiency
- Leakage through heat exchangers
- Effect of leakages and shortcuts on heat recovery
- Definitions of global heat recovery efficiency
- Global heat recovery efficiency
- Net energy saving and performance index
- Examples of application
- Energy for ventilation
- Why check fan power and related quantities?
- Measurement of airflow rate
- Measurement of pressure differences
- Measurement of electric power
- Examples of application
- Energy effects of indoor air quality measures
- Method
- Simulation results
- Recirculation
- Heating
- Cooling
- Filters
- Humidification
- Heat recovery
- Ductwork
- Notes
- 6 Contaminants in Air Handling Units
- Filters
- Ducts
- Humidifiers
- Rotating heat exchangers
- Coils
- Measurement protocols
- Sensory pollution
- Principle of the method
- Selecting the panel
- Training procedure
- Experimental day
- Contaminant transport in rotating heat exchangers
- Principle of the method
- Injection technique
- Air sampling and analysis
- Which VOCs?
- Example of application
- Results
- Evidence for adsorption
- Strategies to improve the performance of HVAC systems
- Notes
- 7 Common Methods and Techniques
- Expressing concentrations and flow rates
- Coherent units
- Corrections for density changes
- Conversion formulae for concentration
- Tracer gas dilution techniques
- Properties of tracer gases
- Mixing tracer gases
- Tracer density problem
- Sampling methods
- Grab sampling
- Passive sampling
- Networks, pumps and pipes
- Injection and sampling port locations
- Injection and sampling sequence
- Tracer gas analysers
- Objective of the analysis
- Infrared absorption spectrometry
- Photo-acoustic detector
- Mass spectrometry
- Gas chromatography
- Chemical indicator tubes
- Calibration of the analysers
- Identification methods
- Linear least square fit
- Linear least square fit of the first kind
- Confidence in the coefficients
- Regression of the second kind
- Orthogonal regression
- Bayesian identification
- Identification of the model parameters
- Error analysis
- Error analysis
- Purpose of the error analysis
- Definitions
- A few statistics
- Average
- Variance and standard deviation
- Covariance
- Statistical distributions
- Confidence interval of the Gaussian distribution
- Error analysis
- What is the problem?
- Most simple error analysis
- Estimate of the variance
- Linear equations systems
- Complete error analysis
- Upper bound of the errors
- Vectorial norms and matrix norms
- Calculation of the upper bound
- Constant absolute error
- Constant relative error
- Notes
- References
- Annex A Unit Conversion Tables
- Introduction
- Multiples and sub-multiples
- Length
- Area
- Volume
- Mass
- Time
- Pressure
- Volume flow rate
- Mass flow rate
- Annex B Glossary
- Index