Airex University VAV Applications Displacement Ventilation

Discussion Items Terminal Unit Systems Single Duct Dual Duct Fan Powered Terminal Unit Options TU Applications & Sizing

The Terminal Unit System CONTROLLER / ACTUATOR DAMPER THERMOSTAT VELOCITY SENSOR THERMOSTAT Measures the air temperature in the space VELOCITY SENSOR Measures the airflow through the unit CONTROLLER /ACTUATOR Receives input from Velocity Sensor / Thermostat, calculates output to Actuator DAMPER Modulates to control space temperature

Flow Sensor Inlet of the terminal Senses amplified velocity pressure which is converted into an electric output in the controller Multi-point center averaging sensor Accurate to +/-5% of any airflow range Provides accuracy no matter the inlet conditions TU TU TU

Single Duct ESV Cooling only - interior zones Single duct with reheat - perimeter

Single Duct ESV Cooling Only Supply Discharge Hot Water/Electric Coil Cooling / Reheat Supply Discharge

Dual Duct System Hot and cold air is blended in unit Provides simultaneous heating and cooling of zones throughout building All air is filtered Air Handling Unit Dual Duct TU

Dual Duct Common Applications Typically used in hospitals and universities Hospitals: For clean air vs. fan powered ceiling plenum heat Universities: For lower sound vs. fan powered terminal units Up to twice the cost of single duct systems Dedicated outside air systems (DOAS) Rising in usage Larger capacity unit needed to overcome pressure drop Requires an access door upstream of the heating coil

Fan Powered Terminals Overview Two basic types Series fan Parallel fan Both utilize heat recovery Recirculate ceiling plenum air

Titus Fan Powered Terminals TQS / TFS / FLS - Series Fan Power Terminal Units TQP / FLP - Parallel Fan Power Terminal Units

Series Fan Terminal Overview Advantages Perceived improved room air motion due to constant volume Constant sound source Used in high profile, sound sensitive applications Disadvantages Operates continuously Larger fan motor since sized for cooling requirements

Series Fan Power Terminal Unit Air path in series with primary Lower inlet static because air only needs to be delivered to the fan Primary Air Return Air Fan Discharge

Series Fan Power Terminal Unit TFS-F FAST TM attenuator Ships internal to the unit Spring clip design/no tools required Shaft down motor Eliminated the need for fan packing Enhanced reliability Lance and tab Motor/ Blower Assembly Faster/easier removal for maintenance staff FAST TM Attenuator Return Air

Parallel Fan Power Terminal Overview Advantages Smaller fans sized only for heating loads Utilizes wasted plenum heat from lights Disadvantages Noise objections from cycling fans

Parallel Fan Terminal Designed for intermittent operation of fan during heat cycle only Smaller fan required - sized only for heating volume During cooling cycle, fan is off, box acts like single duct Primary Air Discharge Air Return Air Fan Back draft Damper

Series vs. Parallel SERIES Constant room air motion due to constant fan Constant sound level Lower system pressure requirements (.50-.75 w.g.) PARALLEL Fan runs during heating only Smaller motor/blower Variable sound level and air volumes Used in high profile, sound sensitive applications Primary Air Return Air Fan Discharge Air Primary Air Return Air Fan Back draft Damper Discharge Air

Options Liners Heat Motors Controls

Linear Types (Insulation) ½" and 1" Fiberglass (standard) ½ and 1 EcoShield Matte and Foil Face Fiber Free SteriLoc UltraLoc (Dual Wall)

Fiberglass ½" and 1" fiberglass Industry standard liner Dual density Typically not specified for hospital or IAQ applications

EcoShield Titus Standard ½ and 1 Cotton Liner (recycled denim) Contains no fiberglass Does not itch or irritate the skin No outgassing or (VOC) concerns Meets all the same req. as fiberglass

Fiber Free ½ and 1 EPFI (Engineered Polymer Foam Insulation) Contains no fiberglass Cleanable surface Low thermal conductivity Very low vapor transmission

SteriLoc Foil face duct board 7/8 thick fiberglass Foil facing provides cleanable surface Sound penalty for reflective surface All edges encapsulated Hospital and IAQ applications

UltraLoc Dual wall liner has 1 fiberglass encapsulated within a metal liner Units are much heavier Sound penalty due to inner metal lining Specified for cleanable surface

Reheat Coils Hot water coils Electric coils Coils are typically selected at the minimum CFM Per ASHRAE discharge temperature + 15 F <= room air temperature

Hot Water Coils Standard (10 FPI) or High Capacity (12 FPI) Pressure tested to 450 psi Located on the discharge side of the Single Duct and Series Fan Powered units Can be on inlet or discharge of Parallel Fan Powered units Adds pressure drop Factor into downstream static

Standard Electric Heat Option Standard 3-stage heater 1 st Stage: 33% 2 nd Stage: 67% 3 rd Stage: 100 %

SCR Electric Heat Time proportioned One stage of heat modulated based on a PWM signal Provides heat based on room load

Lynergy Electric Heat Time proportioned Silent, rapid response solid-state relays Optional Discharge Temperature Sensor PWM Output Actual Room Heat Load Room Heat Requirement 100% 80% 60% 40% 20% 0% 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Off Pulse On Duration of Pulse

Terminal Unit Controls Pressure dependent Volume dependent upon static pressure, no flow limits No velocity sensor or controller required Thermostat and actuator only Can t meet modern ventilation codes

Terminal Unit Controls Pressure independent Volume independent of static pressure (as long as minimum pressure available) Velocity sensor required Thermostat, controller and actuator Minimum and maximum flow limit adjustment

Terminal Unit Controls Pneumatic controls Pressure dependent or independent Requires compressed air system Moderate installed cost (compressor/maintenance)

Terminal Unit Controls Analog electronic controls Pressure independent High accuracy Low installed cost Easy setup - adjustments made at thermostat with screwdriver

Terminal Unit Controls Digital electronic controls Pressure independent Communication capability - dynamic changes possible System integration into BAS High installed cost (network wiring, hardware, software, commissioning, user training)

Terminal Unit Sizing How to size and select terminal units Single duct terminals Series / Parallel fan box terminals Electric Heat sizing

Single Duct Sizing When selecting a box, don t choose a box that is near the top end of the requirement No room for expansion Size for maximum inlet velocity of 2000fpm Allows for typical minimum inlet velocity of 400-500fpm This guarantees easy and accurate damper control

Fan Curves Fan performance is dependent on changes in system pressure Minimum - fan performance at lowest turndown Maximum - fan performance at highest voltage

Inlet Selection Determine inlet size based on cfm requirements When selecting a box, don t choose a box that is near the top end of the requirement No room for expansion Size for maximum inlet velocity of 2000fpm Reduce sound concerns Allows for typical minimum inlet velocity of 400-500fpm This guarantees easy and accurate damper control CFM Inlet Size Range 4 27-225 5 36-350 6 45-500 7 67-650 8 90-900 9 117-900 10 144-1400 12 189-2000 14 302-3000 16 384-4000 24x16 718-8000

Series Fan Box Sizing Select fan at 75% of maximum capacity Select fan for cooling load

Parallel Fan Box Sizing Select fan at 50-75% of maximum capacity Select fan for heating load

Oversizing Issues Most fan box problems caused by oversizing for sound Motor efficiency drops, motor runs hotter, rapid bearing wear, reduced service life, etc. Not necessarily quieter! Motor hum from lower PSC motor speeds

Oversized Terminals Oversized inlets cause problems Limited damper motion Minimum flow control problems Excessive temperature rise for reheat

Electric Heat Rules Minimum kw determined by smallest wire gauge we can use and voltage Maximum kw determined watt density and current draw Minimum airflow is determined by minimum velocity pressure to close airflow switch 45 F max temperature rise across heater 70 CFM/kW

Motor Options PSC motors (SCR controlled) 120 208/240 277 ECM motors 120 208/240 277 Manual PWM Remote PWM

Terminal Unit Motors PSC motors ECM motors Speed controllers Fan curves

Standard PSC Motors Typically specified as highefficiency motor Only when compared to other induction motors Efficiencies from 20 to 60% depending on turndown Fan speed is controlled by SCR

SCR s Speed controlled by SCR (Silicon Controlled Rectifier) A switch that chops the effective voltage to the motor Does not directly control torque Low cost Works well for most applications

ECM Motor Electronically Commutated Motor www.greenspec.com

ECM Benefits Properly developed motor holds constant cfm regardless of changes in static pressure Motor will compensate for dirty filters, etc. Soft start Motors are set to start up slowly, less wear and tear, quieter No wearing of brushes Motor life is ~90,000 hours (30 years of typical series fan powered terminal life vs. 50,000 hours for PSC motor)

ECM Speed Controllers Manual PWM speed control Provides manual adjustment dial with duty cycle % and live RPM readout Remote PWM speed control Accepts 0-10 VDC speed control signal

ECM vs. SCR Watt Comparison 1200 1000 800 TQS 6 @ 0.20 Sp Watts 600 400 ECM PSC 200 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 cfm

ECM Energy Savings 350 watts savings =.350 kw 250 days/year x 12 hours/day = 3000 operating hours/year.350 kw x 3000 hours = 1050 kwh 1050 kwh x $.10* per kwh = $105 per unit per year energy savings!

ECM Fan Curves ECM provides constant volume with changes in pressure 52 Fan curves show constant volume range

VAV Diffusers (T 3 SQ)

T 3 SQ-4 Thermal Description Thermally powered variable volume diffuser Mounted in the popular OMNI diffuser Maintains space temperature www.greenspec.com Available in heating/cooling auto-changeover configuration 54

T 3 SQ-4 Thermal Parts Backpan Thermal Actuator Control Disc Venturi Tube Induction Channel Face Plaque Induction Cap

Face Plaque OMNI plaque with center induction cap Operation instructions and UL listing are on the back of every plaque

Plaque Assembly Unit will ship fully assembled to the plaque Install backpan only

T 3 SQ-4 Thermal Operation Room sensing element located behind induction cap in center of diffuser panel Control disc position varied by wax filled thermal element Wax cools down the actuator assembly retracts under the action of a return spring 58

T 3 SQ-4 Operation 59

Induction 60

T 3 SQ-2 Electronic Diffuser Digital electronic, plug & play Interchangeable master/drone configurations BMS Interface Stand-Alone networked Lonworks BACnet

T 3 SQ-2 Parts

Plaque Assembly OMNI plaque with induction channel and one-piece actuator/control disc assembly Supplied with actuator cable

Backpan Modified OMNI backpan Plug-n-play wiring box Unit ships without actuator connected to backpan

Wiring Interface Box

Control Module / Room Sensor Control module/room sensor Every must have a control module/room sensor 7 day programmable Override capabilities

Power Supply Module 120V / 24V transformer 208V / 24V transformer 277V / 24V transformer 1 RJ-9 connection 2 (4 pin) Mini-fit plenum cable Line voltage field wired

Master Communications Module (MCM) Available in three platforms: Stand-Alone LonWorks BACnet 4 Channels 15 diffusers per 60 total

Master Communications Module (MCM) Information collected per diffuser: Room Temperature Supply temperature Flow rate per diffuser Night Setback Facility Control disc position

Optional Inlet Heater Mounts diffuser neck Requires line voltage 120V, 208V or 277V 2 Thermal cutouts Airflow proving switch ETL Listed

Inlet Heater Powered via separate circuits. Enables Sub-metering Sub-metering via BMS Individual offices and individual diffusers Measurable heating cost on individual diffuser or group of diffusers

Displacement Ventilation Systems Comfort & Contaminates Basic Concepts & System Benefits Outlet Types and Air Patterns Example Space Layouts Displacement & LEED

2015 Application Ch. 57 Fully Mixed Fully Stratified G.R.D. Displacement

Graphic Comfort Zone (5.2.1.1) Met Rate 1.0 1.3 Data based on ISO 7730 And ASHRAE Std. 55 Upper Recommended Humidity Limit 0.012 humidity ratio DPT < 62.2 F 1.0 Clo 0.5 Clo Met Rate 1.0 1.3 70 75 80 Operative Temperature F

Temperature Gradient ASHRAE Standard 55-2010

Cooling Supply Air 48-58 F (8.9-14.4 C) Heating 85-90 F (29.4 32.2 C) Uniform Temperature

Fully Mixed Air Distribution Mixed Contaminates

Cool Air Supply Only 60 F - 68 F (16 C - 20 C ) Low Velocity < 70 fpm (0.36 m/s)

Fully Stratified Air Distribution Light Weight Contaminates Removed

Displacement Ventilation Basic Concepts & System Benefits

Adjacent Zone

Discharge Air Patterns

Standard Air Patterns Adjusted Air Patterns

Basic Concepts & System Benefits Low Energy ( < 0.04 Ps) (10Pa) Air Change Effectiveness (Std. 62.1, Ez = 1.2) Quiet Operation (< 25 NC)

Displacement Cooling

Displacement Stratification

Low Energy Higher equipment efficiency Uses warmer supply air 65 F (18 C) compared to 55 F (13 C)

Low Energy Lower horsepower fans 0.04 in. pressure (10 Pa) is required for proper diffuser performance Results in lower horsepower fans required = Fan Energy Savings

Displacement & Energy Savings Higher equipment efficiency 65 F compared to 55 F Higher discharge temperature reduces energy consumption IEER Temp (off coil) Nom Tons Annual KWH % Energy Savings 13.0 55º 50 92,308 base line 13.0 65º 25 46,154 50.0% 18.0 55º 50 66,667 27.8% 18.0 65º 25 33,333 63.9% Calculations assume 2,000 annual run hours per year and 50% RH in space return

Fan Energy Savings with Displacement Cost of Pressure Supply Total Electricity Annual Diffuser Type Airflow Pressure cost Tp cost (cfm) (Tp) 0.08/KW per diffuser 3-cone 3-Cone Ceiling (TMS) Diffuser 0.06 $0.94 Sq. Plaque Plaque Face Ceiling (OMNI) Diffuser 0.09 $1.41 Louvered (TDC) 400 0.11 $0.08 $1.72 Louver Face Ceiling Diffuser Perforated (PAS) 0.18 $2.81 Perforated Face Ceiling Diffuser DVRI 0.045 $0.78 Displacement Diffuser Ceiling diffusers: 24 x 24, 10 inlet Displacement diffuser: 24 x 79, 10 inlet

Improved Ventilation ASHRAE Standard 62.1 - Ventilation for Acceptable Indoor Air Quality Zone Air Distribution Effectiveness, E z Overhead Cooling System = 1.0 Displacement Ventilation = 1.2 16.7% Less Fresh Air Required

HVAC System Benefits Heat sources outside the stratification layer are not considered in airflow calculations

Return Air Outlet located at ceiling level Allows heat from ceiling lights to be returned before it is able to mix with occupied zone

Humidity Issues Supply system must reduce relative humidity to less than 60% to meet IAQ concerns If 55 o F (13 o C) supply air is used for dehumidification, return air can be mixed with supply air to achieve 65 o F (18 o C) air

Return Air

Perimeter Heating Perimeter heating can not be accomplished with traditional displacement ventilation Separate system required in most applications: Dual Chamber Diffuser

Dual Chamber Diffuser Dual chamber plenum Dual chamber diffuser Displacement cooling Mixed-air heating Actuated diverter (24V) Displacement diffuser cooling Separate Discharge for Heating

Low Level Mixed Heating

Ideal Applications Ceiling Height > 9.0 ft. (2.75m) Open Plan Offices Casinos Theaters & Auditoriums Schools

Displacement Ventilation Advantages Smaller cooling power for desired room temperature in the occupied area Improved air quality in occupied area Longer periods of free cooling

Application Examples Poor Applications Room height < 9 ft. (2.75m) Surplus heat is the main problem not air quality In combination with mixing systems Office/rooms with cubicles Spaces with heavy contaminants

Displacement Ventilation Disadvantages Risk of draft due to placement of the diffusers Wall mounted devices often occupy large wall areas Stratified air becomes uncomfortable when cooling load exceeds ~30 Btu/hr/ft 2 (0.095/kW/m 2 ) Cannot heat with displacement ventilation

Temperature Gradient Ceiling Height 9 (2.75m)- 14 (4.25m) 50% Rule is applied 62 F 72 F 82 F 10 F - 10 F (Displacement ventilation, REHVA)

Temperature Gradient Ceiling Height > 14 (4.25m) 33% 67% 33% Rule 64 F 72 F 86 F 8 F - 14 F (Displacement ventilation, REHVA)

Displacement Ventilation Types of Outlets & Distribution Patterns

Displacement Diffusers Rectangular Mounts in wall 1 way pattern

Displacement Diffusers Rectangular Rectangular In wall, flush or floor mount

Displacement Diffusers Rectangular 3-Way Rectangular In wall, flush or mount floor 3 way pattern

Displacement Diffusers Rectangular Curved Face Flush or floor mount 3 way pattern

Displacement Diffusers Rectangular Stair Riser Steps, Stair Risers applications Great for auditoriums, concert arena s, and lecture halls

Displacement Diffusers Circular Column or floor mount 360º discharge

Displacement Diffusers Semi-Circular 180º Sidewall or column applications 180º pattern

Displacement Diffusers U shaped Semi-circular with straight sides 3 way pattern

Displacement Diffusers Corner w/ Curved Face Corner mount applications 2 way pattern

Displacement Diffusers Corner/Flat Face Corner mount applications 2 way pattern

Displacement Ventilation EXAMPLE Space Layouts

Private Perimeter Office Perimeter Wall

Open Plan Interior Office

Interior Break Room Round Outlets

Perimeter Conference Room Outside Wall

School Classroom Perimeter Wall

ASHRAE Standards for LEED ASHRAE 62.1 IEQ Prerequisite 1: Minimum IAQ Performance IEQ Credit 1: Outdoor Air Delivery Monitoring IEQ Credit 2: Increased Ventilation IEQ Credit 6.2: Controllability of Systems: Thermal Comfort (for naturally ventilated spaces) ASHRAE Standard 55 IEQ Credit 6.2: Controllability of Systems: Thermal Comfort IEQ Credit 7.1: Thermal Comfort: Design IEQ Credit 7.2: Thermal Comfort: Verification

Displacement Ventilation & LEED Minimum Energy Performance: EAp2 Optimize Energy Performance: EAc1 Minimum Indoor Air Quality Performance: IEQ p1 Increased Ventilation: IEQc2 Thermal Comfort Design: IEQc7.1

Publications HVAC Applications Handbook, Chapter 57 (ASHRAE, 2011) Fundamentals Handbook, Chapter 20 (ASHRAE, 2013) System Performance Evaluation and Guidelines for Displacement Ventilation (ASHRAE, 2003) Displacement Ventilation in Non-Industrial Premises (REHVA, 2002)

LSC Terminal Unit Series fan powered terminal unit featuring a SENSIBLE COOLING chilled water coil. Designed to be part of a dedicated outdoor air system (DOAS) DOAS provides an alternative solution to addressing ASHRAE 62.1 ventilation requirements 12

LSC - Configuration Control Enclosure Hanging Brackets (Optional x4) Primary Air Inlet c/w: Aerocross Damper ECM Motor Sensible Cooling Coil ( + Heating Coil Optional) DWDI Blower Electric Heater (Optional) Return Air: Non Ducted Ducted (Optional) Filter MERV8 (Optional) Condensate Pan ECOSHIELD STD ½ Liner

LSC - Configuration Primar y Air Return Air LSC Terminal Unit Multiple Discharge Grilles

SOLUTION FOR SCHOOLS Displacement, chilled beams and radiation principles. Induction Nozzles Tempered and dry primary supply air delivered at 55ºF Induced room air and mix to discharge air at appropriate temperature Heat Transfer Coils Room air induced through coils Sensible load handled by the coil Eliminates separate Heating system

TAO Section View

TAO: Cooling mode operation Cooling Mode Supply Airflow (70 to 71 ºF) Return Air 100% Exhausted Primary Airflow (55 to 58ºF) Chilled Water Room Air (75ºF) Supply Airflow (62 to 63ºF)

TAO: Heating mode operation Heating Mode Exhausted Supply Airflow (85-92ºF) Optional Heat Recovery Primary Airflow 450 CFM (62-66ºF) Room Air 900 CFM (70-72ºF) Supply Airflow (67-70º F)

Potential for Increased Economizer San Francisco 55 F = 158 Days: 65 F = 365 Days: 207 Difference Dallas 55 F = 107 Days: 65 F = 177 Days: 70 Difference Chicago 55 F = 209 Days: 65 F = 263 Days: 54 Differenc (based on average daily temperatures)

Dual Duct Types Different designs for different mixing requirements Non-Mixing Standard Mixing High Mixing

Mixing Characteristics EDV (Non Mixing) - 1:10 For 10 F EAT Variance, there is 1 F differential 4 duct diameters downstream MDV (Mixing) - 1:20 Higher Ratio Sound Penalty

Dual Duct Terminal Unit Mixing Cold Supply Hot Supply Blended Discharge Non-Mixing Cold Supply Hot Supply Cold Discharge Hot Discharge

Thank You!