indoor air quality element in acmv...

Indoor Air Quality Element in ACMV Design

Presented by:

Ir. Muhammad Fadzli B. Muhammad Saleh

Outline of Presentation

• Objectives

• Introduction

• Types of ACMV System in Malaysia

• Primary Components

• IAQ Concerns in ACMV Design

Conceptual Design

Preliminary Design

Detail Design

Design Validation

• Case Study

Objectives

• Able to identify Indoor Air Quality (IAQ) parameters that could be directly caused/affected by ACMV System

• Able to recognize primary components for various types of ACMV in Malaysia

• Briefly understand the adaptation of IAQ element at various levels of ACMV design process

Introduction IAQ ELEMENT IN ACMV DESIGN

IAQ and ACMV

• Main references in IAQ subjects:

i. Industry Code Of Practice on Indoor Air Quality (DOSH 2010)

ii. Indoor Air Quality : A System Approach (SMACNA)

iii. Indoor Air Quality Guide: Best Practices for Design, Construction and Commissioning (ASHRAE 2013)

iv. ASHRAE Standard 62.1 – Ventilation for Acceptable Indoor Air Quality

IAQ and ACMV

• What is IAQ :

- “The state of the environment in a space occupied, or intended to be occupied, by human beings specifically concentrating on the constituents in the air which are not considered to be part of normal, fresh outside air.” (SMACNA, Jan 1998)

• How do we control the state of environment in an occupied space?

AIR –CONDITIONING AND MECHANICAL VENTILATION SYSTEM (ACMV)

IAQ Parameters (COP)

• Physical Parameters

i. Air Temperature 23 – 26 oC

ii. Relative Humidity 40 – 70 %

iii. Air Movement 0.15 – 0.50 m/s

• Chemical Contaminants

i. Carbon Monoxide

ii. Formaldehyde

iii. Ozone

iv. Respirable Particulates

v. Total Volatile Organic Compounds (TVOC)

IAQ Parameters (COP) continued..

• Biological Contaminants

i. Total Bacterial Counts

ii. Total Fungal Counts

• Ventilation

i. Carbon Dioxide Level as indicator

• Which parameters from the above are directly affected by ACMV design?

Physical Parameters

Ventilation

Air-Conditioning & Mechanical Ventilation System (ACMV) IAQ ELEMENT IN ACMV DESIGN

Type of ACMV in Malaysia

• Mechanical Ventilation System (Ducted or Direct)

• Conventional Split Unit System

• Multi Split Unit System

i. Conventional

ii. Variable Refrigerant Flow (VRF)

• Air Cooled Packaged System

• Water Cooled Packaged System

• Air Cooled Chiller System

• Water Cooled Chiller System

Primary Components of ACMV

• Axial Fan (Wall Type)

Primary Components of ACMV continued..

• Axial Fan (for ducted installation)


• Centrifugal Fan


• Condensing Unit


• Indoor Unit (Fan Coil Unit)

Wall mounted type Universal type

Concealed Duct type Ceiling Cassette type


• Indoor Unit (Fan Coil Unit)

Floor Ceiling type (ceiling expose) Floor Standing type


• Air Handling Unit


• Supply Air Diffuser


• ACMV Ducting


• Return Air Grill


• Water cooled Chiller


• Air Cooled Chiller


• Chilled Water Pumps


• Condenser Water Pumps


• Cooling Tower

IAQ Concerns in ACMV Design IAQ ELEMENT IN ACMV DESIGN

Video/EPA's 5 Indoor Air Quality Categories of Concern.mp4

IAQ Concerns in ACMV Design

• IAQ concerns in ACMV Design should be prescribed to meet the objectives for improving building IAQ suggested in ‘Indoor Air Quality Guide: Best Practice for Design, Construction, and Commissioning’ developed by ASHRAE and SMACNA: i. Manage the design and construction process to achieve good IAQ

ii. Control moisture in building assemblies

iii. Limit entry of outdoor contaminants

iv. Control moisture and contaminants related to mechanical system

v. Limit contaminants from indoor sources

vi. Capture and exhaust contaminants from building equipment and activities

vii. Reduce contaminant concentration trough ventilation, filtration and air cleaning

viii. Apply more advance ventilation approaches


continued ..

• IAQ concerns are addressed according to various phases of ACMV Design.

• Conceptual Design Stage

i. Select system that could provide proper ventilation - Wall Mounted AC Split?

- Ceiling Cassette AC Split?

- Ceiling Conceal AC Split?

- AHU?

ii. Provide a way to purge/remove out contaminated indoor air before handing over the building to client.

- naturally

- mechanically


continued ..

• Preliminary Design Stage

i. FCU/AHU should be located at the area where chances for it to be contaminated is as low as possible.

- Avoid near wet area

- Avoid near cafeteria

- Toilet / wash room

ii. Separate air-side system for high risk contaminated room. Full height partition should be provided by the architect.

- Toilet

- Archive Room

- Cafeteria

- Laboratory

- Operation Theater

iii. Fresh air / air inlet opening for ACMV should be located away from any contaminated or high risk contaminated room/space.


continued ..

• Detail Design Stage

i. Cooling Load Estimation and Air Side ACMV design should comply to the ICOP acceptable range:

- Air Temperature 23 – 26 oC

- Relative Humidity 40 – 70 %

- Air Movement 0.15 – 0.5 m/s

ii. For good ventilation, the air side of ACMV should be designed meet minimum recommended outdoor air-rate per person (ASHRAE Std. 62.1):

- Office Space 5 cfm/person & 0.06 cfm/ft2

- Mall & Supermarket 7.5 cfm/person & 0.06 cfm/ft2

- Restaurant & Café 7.5 cfm/person & 0.18 cfm/ft2

- Games Arcade 7.5 cfm/person & 0.18 cfm/ft2

- Computer & Science Lab 10 cfm/person & 0.18 cfm/ft2

- Disco & Aerobics Room 20 cfm/person & 0.06 cfm/ft2


continued ..

• Breathing Zone Outdoor Airflow (Vbz)

Vbz = Rp x Pz + Ra x Az

Where:

Rp required outdoor airflow rate per person (cfm)

Pz zone population (number of people)

Ra required outdoor air flow rate per unit area (cfm/ft2)

Az zone floor area (ft2)


continued ..

• Design Validation Stage

i. Carried out after the client occupied the building. (Not During Testing and Commissioning)

ii. Very important to measure the effectiveness of the applied design and for continuous design improvement

iii. How is it conducted? - IAQ parameters that directly related to ACMV design are measured

and compared to the same parameters in the design stage.

- Physical parameters like dry and wet bulb, relative humidity , CO2 level and air velocity can be measured directly using measuring instruments.

- Outdoor air-rate can be calculated using the measured parameters by applying the formula below:

%OA = ((CSA – CRA) / (CRA – COA)) x 100

QOA = %OA x QS


continued ..

• Where :

%OA Percentage of Outside Air

QOA Volumetric Flow Rate of Outside Air in CFM

CSA Supply Air CO2 Concentration into the room/space

CRA Return Air CO2 Concentration (in AHU Room)

COA Outside Air CO2 Concentration

QS Total Supply Air Flow Rate into the room

Case Study

The top management of CKM has received several complaint forms regarding the venue where trainings are usually conducted; “Bilik Latihan”. Most of the forms state that students are usually feeling sleepy during lecture. It is suspected that insufficient supply of the outdoor air inside the room is the main reason why it is happening..

As an IAQ assessor, you are asked to investigate whether or not this ‘Bilik Latihan’ has a sufficient outdoor air supply?

• Air Flow Rate per Diffuser 350 cfm

• Measured CO2 concentration of Supply air 610ppm

• Measured CO2 concentration of Return air 650 ppm

• Measured CO2 concentration of Outdoor air 500 ppm

• Area of “Bilik Latihan” 600 ft2

Objectives

• Able to identify Indoor Air Quality (IAQ) parameters that could be directly caused/affected by ACMV System

• Able to recognize primary components for various types of ACMV in Malaysia

• Briefly understand the adaptation of IAQ element at various levels of ACMV design process

Sekian, Terima kasih

Presented by:

Ir. Muhammad Fadzli Muhammad Saleh

Jurutera Mekanikal Kanan

Cawangan Kejuruteraan Mekanikal

Email : [email protected]

Office no :0326189487

H/p no :0103664321

mailto:[email protected]

indoor air quality element in acmv...

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