systems for msbo-hvac (part 1) [read-only] · basically all commercial units function like this...

9/18/2017

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Nicholas Thornton, CEM

1Systems: HVAC, Electrical, and Technology

Overview� Today’s Goals

� Introductions

� HVAC

� Electrical

� Technology

� Q&A


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Today’s Goals� An overview, a crash course

� Maybe a few ‘tangents’ (ASK QUESTIONS!)

� Show typical arrangements / equipment

� Provide some resources

� Brand agnostic

� Have fun


A bit about me…� Energy Engineer for Siemens for 2 ½ years

� Energy Manager for 8 years (Schools)

� Construction manager (Bond renovations) for schools for 7 years

� Some facility consulting along the way


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Introductions� Name

� Role

� Company / School District

� One thing you hope to learn today


HVAC� Function / Definition

� Components

� Tips & Resources


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HVAC: What?!� Heating, ventilation and air conditioning (HVAC)[1] is

the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a sub discipline of mechanical engineering…

� ...Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, or ventilating is dropped as in HACR …

� (Wikipedia 8.2.2017)


HVAC: Put simply…� Equipment & Systems that provide Heating, Ventilation,

& Air Conditioning, usually including refrigeration, Process, and Central Plant stuff


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HVAC: Basic Functions� Heating

� Ventilation

� Air Conditioning

� Dehumidification / Humidification

� Air Cleaning: Filters, UV, Air Washers

� Safety: CO2, VOCs, refrigerant monitoring, etc.

� Process Loads: cooling of test equip

� Domestic Hot Water

� Steam Power


HVAC: ‘House stuff’ on steroids� Might Run 24/7

� More variable loads

� More CO2 & odor concerns

� Bigger

� Usually has more outdoor air

� Usually has free cooling sequence (attic fan in your house)

� Usually utilizes a central plant


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HVAC: Start to Finish


Boilers & Chillers

Cabinet UnitHeater

VAV Box

Reheat Coils

Pumps

Strainers

Circuit Setters

Balance Valves

Roof Top Unit

(RTU)

Air Hander/

Supply Unit (AHU)

Unit Ventilator

(UV)

RTUs, UVs, AHUs:

The Basic H Diagram


ReturnAir

SupplyAir

OutsideAir

ExhaustAir(ReliefAir)

ReturnFan

SupplyFan

Dam

per

s

Heating/Cooling ‘Coils’

Fil

ters

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HVAC: The Basic H Diagram� Basically all commercial units function like this

� Extras: Humidification, more filters, UV lamps, etc.

� Can be variations:

� Energy Recovery (take energy from exhaust air and add into incoming outside air)

� No Return: 100% outside air…for labs…100% exhausted

� Different types of economizer programming (for determining when it’s best to use 100% outside air instead of return air)


HVAC: The (Complex) H Diagram


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HVAC: The (Complex) H Diagram


HVAC: The Basic H Diagram� Doesn’t have to be in the shape of an ‘H’…

� Can be in multiple pieces

� Relief or Exhaust on the roof

� Relief or exhaust in a different room

� Let’s look at some pictures…


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HVAC: Unit Ventilators


HVAC: Air Handlers


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For Large Air Handlers…� Some units serve a single room (zone) like a gym. They

turn on & off (like a house) OR they run constantly and modulate supply air temp to meet the temperature set point of the zone.

� Some units provide HVAC to multiple rooms …


For Large Air Handlers…� How to control temperature in each room?

� No individual control (i.e. like your house)..just one room has a thermostat

� VAV Box (Vary the air volume of cold air into each room)

� Reheat Coil (Add heat to the airstream at each room)

� These are called terminal units

� Frequently these units produce ~55° air all the time (for dehumidification and cooling capacity purposes for interior rooms)


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Terminal Units


~55 ° AHU/RTU

55 °

(No Control)

55-85 °

Reheat Coil

55-85 °

VAV Box w/

Reheat Coil

55 °

(just more or less)

VAV Box


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Air Handler Life Hacks� Keep filters clean (4x / year)

� Keep condenser coils clean (1x/ year)

� Consider cleaning heating coils if older units

� If older units, insulation can break down…can be sealed

� 55 degree air…otherwise no de-humidification happens

� Return (or exhaust) air is important…can’t put more air in without removing some

� Scheduling off when unoccupied saves big $$


Boilers� Turn fuel (natural gas, propane, fuel oil, etc.) into heat

� Put heat into: hot water, steam, high-temperature hot water

� Usually in pairs (redundancy), sometimes 3 or more

� Ideally a ‘closed’ (recycled water) system, except for leaks

� Some steam systems are ‘open’ where used steam (condensate) is dumped down the sewer or used for process and not returned to the boiler


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Boilers


Boilers-Life Hacks� Take care of steam traps (Number, inspect annually,

REPAIR)…~ 5% fail per year! ($$$)

� Have your Boilers tuned/check annually (CSD-1 Testing)

� Check for frequent, accidental condensing operation

� Some boilers are designed for < 140° (look for drain line from the boiler)

� Running boilers < 140° can be damaging if not designed for this

� Check your water chemistry (bio growth, oxygen pitting)


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Chillers� Move heat from one spot to another

� Air Cooled (one unit)

� Water Cooled (2 units) (+cooling tower or lake water)

� Electric or Steam-driven

� Frequently in pairs (redundancy), sometimes 3 or more

� A ‘closed’ (recycled water) system, except for leaks


Chillers


Water To/From Tower (Reject Heat)

WaterTo/From Building(Absorb Heat)

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Chillers-Water Cooled


Chillers-Water Cooled (Towers)


CoolingAir

(Reject Heat)

Water To/From Building(Absorb Heat)

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Chillers-Air Cooled (One unit)


(Reject Heat)

Water To/From Building(Absorb Heat)

Cooling Air

Chiller Life Hacks� Clean the condenser coils (1x/year)-Air Cooled

� Clean the condenser barrel tubes (1x / year)-Water Cooled

� Check your water chemistry (bio growth, oxygen pitting)


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Pumps & Stuff� Pumps move water (sometimes part glycol-antifreeze)

� At the boiler/chiller

� Around the central plant

� Around the building

� At the heating/cooling coil (when a boost is needed)

� Flow is controlled (fine tuned) by:

� VFD (dynamic)

� balancing valve

� Impeller size


Pumps & Stuff


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Pumps & Stuff


� Motor

� Pump

Pumps…more than just one


Chillers / Heat

Exchanger

Bypass

Pump w/VFD

38 - 86 deg F43 deg F 42 deg F

Condenser Loop

TowersBypass

Primary Loop

Secondary Loop

Air Handlers & Process

Equipment

44 deg F

Pump w/VFDPump w/VFD Pump w/VFD

50-56 deg F 50-56 deg F 50-56 deg F

Building Loop

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HVAC: Random Thoughts� Not all systems are equally efficient

� Controls are not all equal (even two controllers from the same vendor on two identical units might have different logic inside)

� Things that are working ‘fine’ can:

� Still be made more efficient (cleaning, comissioning, programming)

� Headed towards failure (imagine a VFD running at 100%...)


Some Final HVAC Tips� PM is super helpful on any HVAC system

� Start with a ‘list’ of your equip. (age, manuf., size, etc.)

� RTU, AHU (Gym, Cafeteria, Office)

� UV’s (Classrooms)

� Cabinet Unit Heaters (Vestibules, Hallways)

� Boilers, Chillers

� Pumps


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Questions?


systems for msbo-hvac (part 1) [read-only] · basically all commercial units function like this...

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