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In-House Training Air Conditioning & Mechanical Ventilation Basic Design – Part 1 April 2017

In-House Training Air Conditioning & Mechanical Ventilation Basic Design – Part 1 April 2017. Design Resources and Objectives. Agenda. Mechanical Ventilation Design. Air Conditioning System Design. Our Knowledge Centre. The KC provides design resources for your use, including:

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In-House Training Air Conditioning & Mechanical Ventilation Basic Design – Part 1 April 2017

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  1. In-House TrainingAir Conditioning & Mechanical VentilationBasic Design – Part 1April 2017

  2. Design Resources and Objectives Agenda Mechanical Ventilation Design Air Conditioning System Design

  3. Our Knowledge Centre The KC provides design resources for your use, including: • Design Guides • Calculation Templates • Work Examples • Codes & Standards

  4. Design Manual • Identifies relevant codes and regulations • Explains common calculation methods. • Provide commentary on important considerations and issues

  5. Design Objectives & Criteria

  6. Think WHY? Before WHAT? • Understand the function and arrangement of the space • Consider the needs of the occupants and equipment in the space • Identify design criteria for success and only then consider WHAT & HOW.

  7. Objectives – Comfort • Controlling environment for occupant comfort: • Temperature • Humidity • CO2 Common Applications: • Offices and shops • Kitchens • Factories Essential Reading: Design Criteria & Thermal Comfort: ACMV DM Chapter 1

  8. Objectives – Health • Removing and diluting airborne contaminants • Common Applications: • Smoking Areas • Carparks • Workshops Essential Reading: SS 553 & SS554

  9. Objectives – Performance • Controlling environment for equipment or process performance • Common Applications: • Electrical Switchgear Rooms • Data Centres • Mechanical rooms with high heat release • F&B Plants

  10. Objectives – Life Safety • Controlling environment for life safe purposes • Common Applications: • Exit Stair Pressurisation • Smoke Purging of basements • Smoke Control of large spaces or high population spaces

  11. What are the needs of this space ? OFFICE

  12. What are the needs of this space ? Car Park

  13. What are the needs of this space ? Chiller Plant Room

  14. Design Resources & Objectives Agenda Mechanical Ventilation Design Air Conditioning System Design

  15. Topics • Code Requirements • Types of Fans • Ductwork System Design • Ventilation Applications

  16. Codes & Regulations • Code of Practice for Fire Precautions in Buildings 2013 (‘The Fire Code’) • - Chp 2 Means of Escape • - Chp 7 ACMVare most relevant • SS530 Energy Efficiency Standard for Building Services & Equipment • - Maximum energy use for equipment • SS553 Code of Practice for Mechanical Ventilation and Air Conditioning in Buildings

  17. SS553 Adresses Many Issues • Ventilation rates in SS553are minimums. Beca recommendations often higher. • Defines ventilation system energy efficiency • Defines ventilation system materials • Defines ventilation system controls.

  18. Codes & Regulations • SS 550 Code of practice for Installation, operation and maintenance of electric passenger and goods lifts. • SS532 The Storage of Flammable Liquids. • - Generator & Diesel Storage Rooms • - Laboratory Fuel Storage • CP 51 CP Manufactured Gas Pipe Installation • - Kitchen Ventilation Control

  19. Codes & Regulations • Code of Practice on Environmental Sustainability of Buildings + GreenMark certification standards • The GM certification level also will dictate the require energy efficiency of our ACMV systems. • Need to agree targets with ESD team at early stage. • Will drive system selection decisions.

  20. Fan Types

  21. Equipment-Propeller Fans • Low pressure • Not so efficient • Usually use for wall-mounted installation

  22. Propellor fan

  23. Equipment - Axial Fans • Higher pressure • More efficient • Increase pressure by using 2-stage fans in series • Can adjust fan capacity by blade angles, more blades or inlet guide vanes • 1440 rpm or less to minimise noise

  24. Equipment – Centrifugal Fans • Higher air flow • Higher pressure • Highest efficiency • Less noise • Motors are outside the air stream allow easy maintenance • Easy to adjust fan speed • Take up more space • Higher cost Centrifugal fan

  25. Ductwork Systems

  26. Maximum Air Velocities Carpark & Plantrooms Typical Office • These are maximum velocities. Typically use 80% of these figures

  27. Good and bad practices (Axial fan)

  28. Good and bad practices (Axial fan)

  29. Good and bad practices (Axial fan)

  30. Good and bad practices (Centrifugal fan)

  31. Good and bad practices (Noise control)

  32. Good and bad practices (Noise control)

  33. Natural Ventilation • Natural ventilation are solutions becoming much more common as sustainability objectives increase • Manual calculations and simulation can be used. Essential Reading: Natural Ventilation Design Manual Section 2.4

  34. Duct Sizing Calculations - Use the Beca Calculation template on the Intranet - Refer to the Worked Example also in the template - A short list of duct C Factors is included in the Template. Beca Template: Ductwork Resistance

  35. Ventilation Applications

  36. Exit Staircase and Internal Passageway • Supply air only required • 4 air changes per hour • For > 4 storeys, duct outlets at alternate floor • Duct transverses out of staircase be fire rated - No fire damper

  37. Smoke Stop & Fire Fighting Lobby Ventilation • Supply air only • Normal Operation: 4 air-changes per hour • Fire Operation: 10 air-changes per hour • Link to fire alarm system to trigger speed change • Remote manual start-stop swich at FCC • Emergency Power Supply Beca Template: Stair & SLL Vent + PressurisationCalc Beca Template: Space Planning

  38. Staircase Pressurisation

  39. Staircase Pressurisation • For internal exit staircases and building with more than 4 basements or over 24m high • Supply air only • Link to fire alarm system • Remote manual start-stop switch at FCC

  40. Staircase Pressurisation a) Maintain air movement though doors Velocity, V = 1 m/s b) Door Leakage = (Number of stair doors x Leakage area x pressure difference) c) Shaft Leakage = 25% additional flow allowance Ventilation rate = a) + b) +c) Beca Template: Stair & SLL Vent + PressurisationCalc

  41. Kitchen Exhaust System Schematic Kitchen Exhaust Make Up Air Cooling / PAU KITCHEN DINING ROOM Transfer Air

  42. Kitchen Exhaust

  43. Kitchen Exhaust System • Size cooking hood exhaust using SS 553 face velocity method • General ventilation allow 20 ACH • Create negative pressure in kitchen • No fire damper allowed. Fire rate the duct that traverses out of kitchen • No more than 50% of make up air can be cooled (SS553) • All fumes must be treated with air cleaning system, before discharging at the roof

  44. Kitchen Exhaust Systems • Don’t share with MV systems serving other places • Kitchen hood required for appliances with heating capacity > 8KW and likely to generate grease vapour. • Interlock with gas solenoid valve: When exhaust fan fails or not operating, cut-off gas supply • Provide dedicated makeup air where exhaust rate exceeds outdoor air into the dining area. Cool make up to provide spot cooling.

  45. Ventilation of Carparks • There are three ventilation options: • Natural Ventilation • Fume Extract (low air change exhaust only) • Mechanical ventilation

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