9/18/2017. Nicholas Thornton, CEM. Systems: HVAC, Electrical, and Technology. Overview. Today s Goals Introductions HVAC Electrical Technology Q&A

Transcription

1 Nicholas Thornton, CEM 1 Overview Today s Goals Introductions HVAC Electrical Technology Q&A 2 1

2 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 3 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 4 2

3 Introductions Name Role Company / School District One thing you hope to learn today 5 HVAC Function / Definition Components Tips & Resources 6 3

4 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&Ror HVACR, or ventilating is dropped as in HACR (Wikipedia ) 7 HVAC: Put simply Equipment & Systems that provide Heating, Ventilation, & Air Conditioning, usually including refrigeration, Process, and Central Plant stuff 8 4

5 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 9 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 10 5

6 HVAC: Start to Finish Roof Top Unit (RTU) VAV Box Reheat Coils Air Hander/ Supply Unit(AHU) Boilers & Chillers Pumps Strainers Circuit Setters Balance Valves Unit Ventilator (UV) Cabinet Unit Heater 11 RTUs, UVs, AHUs: The Basic H Diagram Exhaust Air (Relief Air) Outside Air Dampers Return Fan Supply Fan Return Air Supply Air Filters Heating/Cooling Coils 12 6

7 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) 13 HVAC: The (Complex) H Diagram 14 7

8 HVAC: The (Complex) H Diagram 15 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 16 8

9 HVAC: Unit Ventilators 17 HVAC: Air Handlers 18 9

10 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 19 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) 20 10

11 Terminal Units ~55 AHU/RTU 55 (No Control) (just more or less) Reheat Coil VAV Box VAV Box w/ Reheat Coil

12 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 $$ 23 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 24 12

13 Boilers 25 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) 26 13

14 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 27 Chillers Water To/From Tower (Reject Heat) Water To/From Building (Absorb Heat) 28 14

15 Chillers-Water Cooled 29 Chillers-Water Cooled (Towers) (Reject Heat) Cooling Air Water To/From Building (Absorb Heat) 30 15

16 Chillers-Air Cooled (One unit) (Reject Heat) Water To/From Building (Absorb Heat) Cooling Air 31 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) 32 16

17 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 33 Pumps & Stuff 34 17

18 Pumps & Stuff Motor Pump 35 Pumps more than just one Pump w/vfd 44 deg F Pump w/vfd Pump w/vfd 43 deg F 42 deg F Pump w/vfd deg F Air Handlers & Process Equipment Bypass Bypass Chillers / Heat Exchanger Towers deg F deg F deg F Building Loop Secondary Loop Primary Loop Condenser Loop 36 18

19 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%...) 37 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 38 19

20 Questions? 39 20