MECHANICAL SERVICES 101 Ian White
Contents 1. Ventilation 2. Heat Gains & Losses 3. Heating Ventilation Air Conditioning (HVAC) Systems
What are Building Services Building Services incorporate all aspects to make a building comfortable. Mechanical Services include: Ventilation Heating & Cooling Costs associated: 10-15% construction cost 25% operational cost Smoke Control Controls and Building Automation
BUILDING SERVICES ENERGY CONSUMPTION Base Building Tenancy
WHAT IS COMFORT CLOTHING INSULATION METABOLIC RATE RADIANT TEMPERATURE
COOLING LOADS
HEATING LOADS
Heating and Cooling Gains Time of Day Time of Year Climatic Conditions Building Orientation Occupancy Activity Equipment Use
AIR CONDITIONING Creating a controlled climate in indoor living or working areas for the comfort or for the proper performance of some industrial or scientific process.
AIR CONDITIONING Removing & Transporting Heat - Absorb heat from space - Transport heat away from space - Reject heat from system
SYSTEM COMPONENTS: COOLING Heat transfer process from space to atmosphere
SYSTEM COMPONENTS: HEATING Heat transfer process to space
PLANT LOCATIONS CENTRAL PLANT: 1.Hot Water 2.Cold Water 3.Heat Rejection
PLANT LOCATIONS LOCAL PLANT: 1.Hot Water 2.Cold Water 3.Heat Rejection
SYSTEM DESIGN: ZONING
Medium for Transfer of Heat 1.REFRIGERANT = Small Pipes 2.WATER = Medium Pipes 3.AIR = Big Ducts
Refrigerant THE REFRIGERATION CYCLE
Refrigerant Direct Expansion (Split DX) Wall Mounted Split Package
Variable Refrigerant Volume VRF/VRV
Water Ducted PAC Units + Cooling Tower
Water Chilled Beams Chilled Ceilings
Water Chilled Beams
Water Fan Coil Units
Air Handling Units
Air Handling Units
CARBON FILTER MANOMETERS BAG FILTER PANEL FILTER GREASE FILTER
CHILLERS FUNCTIONS -Chilled water systems -Cool water transported by pumps & pipes -Water circulated through coils to cool air in an A/C system or through manufacturing or industrial process TYPES -Vapour-compression refrigeration cycle Driving source: compressor (electricity) Different type of compressors -Absorption refrigeration cycle Driving source: heat Condenser types: air or water cooled
CENTRIFUGAL CHILLER SCREW CHILLER RECIPROCATING CHILLER ABSORPTION CHILLER
Air Cooled Chiller
Water Cooled Chiller
HEAT REJECTION FUNCTION -Transfer heat from cooling medium & discharge to ambient TYPES -Cooling towers -Dry coolers -Adiabatic coolers -Harbour Cooling -Geothermal
HEAT REJECTION
COOLING TOWERS BENEFITS -Energy efficiency -Long equipment life CONSIDERATIONS -Water treatment e.g. legionella -Condenser tube washing & tower maintenance -Freeze protection -Makeup water
WATER SOURCE HEAT PUMP
WATER SOURCE HEAT PUMP
GEOTHERMAL HEAT PUMP
GEOTHERMAL HEAT PUMP
HEATING HOT WATER HEATERS FUNCTIONS -Hot water systems -Heat water transported by pumps and pipes -Water circulated through coils to heat air in an A/C system or through manufacturing or industrial process Types -Atmospheric or forced draught -Modular -Condensing
HEATING EXCHANGERS FUNCTIONS -Heat exchange -Heat recovery Types -Water to Water -Water to Air -Air to Air PLATE HEAT EXCHANGER COIL ENTHALPY WHEEL CROSSFLOW HEX
PUMPS FUNCTION -Circulate fluids through systems TYPES -Centrifugal -Back pull-out or in-line SELECTION -Water flow vs. Static pressure
FANS FUNCTION -Circulate fluids through systems TYPES -Axial -Centrifugal -Forward or backward curved SELECTION -Air flow vs. Static pressure -Acoustics -Equipment dimensions -Configuration
VARIABLE SPEED DRIVE FUNCTION -Control the rotational speed of an electric motor Fans & Pumps -Reduced energy consumption (part load operation) -Noise reduction -Smart controllers Compressors (chillers) -Ability to match the capacity to the actual need -Reduced costs: energy savings, lower installation costs caused by optimisation of the system and the compressor itself
Conventional All Air System
Displacement System
Chilled Beams
Chilled Ceiling
Chilled / Heated Slab
SYSTEM SELECTION & DESIGN Based On: -Comfort criteria -Thermal loads -Space considerations: plants and reticulation -Installation vs. operating costs -Economy of scale -Flexibility & maintenance -Simplicity of control strategy -Operation efficiency -Fine tuning for different users -Single / multiple point of failure
SYSTEM SELECTION & DESIGN All Air Central Systems -Constant Air Volume (CAV) -Variable Air Volume (VAV) Air & Water Systems -Induction systems -Fan coil systems -Chilled beams or chilled ceiling systems Limitations -Temperature -Noise -Cost
BUILDING MANAGEMENT SYSTEM FUNCTION -Control of mechanical services -Monitoring & Management -Energy use -Alarms & Fault finding -Interface or integration of hydraulic, security, lighting, metering systems
SAVE THE DATE: HYDRAULIC SERVICES 101 ELECTRICAL SERVICES 101 FIRE PROTECTION SERVICES 101 xxxxx