SureFlow: A Paradigm Shift in Fan Coil SystemsUniversity of North Carolina at Greensboro – Edward Keller

Thermal Resource Sales, Inc. – Patrick McNamara, PE

Presenters:

Ed Keller – UNCG, Associate Director for Operations for Housing and Residence Life 

Patrick McNamara, PE – TRS‐Greensboro Manager, SESCO Engineering, P.C. – President 

A little bit about Ed…

A little bit about Patrick…

Who is TRS/SESCO?• Founded in 1996 as McNamara & Co.• Separately incorporated as TRS & SESCO in 1998.• Today we are approximately 90 total employees 

with 40 outside sales engineers across 3 states. • TRS represents 70+ manufacturers across the 

Carolina’s and Georgia focusing on custom engineered, energy efficient MEP equipment.

• TRS has a full service division supporting equipment installations, start‐up, commissioning, and warranty.

• SESCO business model includes engineering services, equipment procurement, and commissioning services.

• SESCO has completed 2,500+ supermarket projects stretching from Maine to Florida.

5

1. Introduction – Ed Keller, UNCG2. Fan Coil 101 – Patrick McNamara, TRS/SESCO3. SureFlow: A Paradigm Shift – Patrick McNamara, TRS/SESCO4. Rubber Meets The Road: Grogan and Cone Hall – Ed Keller, UNCG5. From The Owners Perspective – Ed Keller, UNCG6. Conclusion – Ed Keller & Patrick McNamara

OUTLINE

Fan  + Coil = Fan Coil

Room Fan‐Coil Performance RatingListed Per ANSI/AHRI Standard 440 

What Is A Fan Coil ?

Condensate Drain Pan

Thermostat

Air Filter

Return Air From Room

Return Water

Standard Coil Operation

Supply Water

Supply Air To Room

6-14 Fins Per Inch

1-12 Rows

Hot or Cold Water

Face Area ≈ 1 Sq Ft Per Ton

Tube Water Velocity2 < 7 Ft Per Second

Air Velocity Max≈ 450 Ft Per Minute

WPD, APD, & BTU’s

Always use Stainless Steel Casings on Chilled Water Coils

Coil Designs

10

CHILLERCHILLERFAN COIL

HEAT REJECTED OUTSIDE –WATER IS CHILLED

PUMP

PIPINGSYSTEM

HEAT REMOVED FROM ROOM AIR

42-47° FWater

Cooling Operation

BOILERBOILERFAN COILHEAT DELIVERED

TO ROOM AIR

PUMP

PIPINGSYSTEM

WATER IS HEATED WITH

ENERGY (NATURAL GAS, ELECTRICITY,

PROPANE, STEAM)

130-180° FWater

Heating Operation

FCU

ChillerChiller

FCUFCUFCU

Central Pump Drives Water Through Piping to Supply Each Fan Coil

Direct Return

ChillerChillerFCU FCU FCU FCU

Supply

Return

Express Return

Reverse Return

FCU

ChillerChiller

FCUFCUFCU

BoilerBoiler

What do I do if I want heat?Complain!

Boiler is OFF

2‐Pipe Heat / Cool Changeover = All Units Are Either Cooling or Heating

FCU

ChillerChiller

FCUFCUFCU

BoilerBoiler

What do I do if I want cool?Complain!

Chiller is OFF

2‐Pipe Heat / Cool Changeover = All Units Are Either Cooling or Heating

ChillerChiller BoilerBoiler

FCUFCUFCUFCU

4-Pipe Heat / Cool =Units May Cool or Heat Any Time

ChillerChiller BoilerBoiler

FCU

Supply

Return

4-Pipe Heat / CoolHow Is It Controlled ?

Determined from several parameters:• Coil Length• Coil Rows• Tube Circuits• GPM Flow Rate• Water Temperature

Example@ 3.0 GPMCoil PdFt = 5.9

Coil Pressure Drop

FCU

ChillerChiller

FCUFCUFCU

Ball Valves For Service / Isolation

ChillerChiller

FCUFCUFCUFCU

Add Control Valves and Thermostats ForIndividual Comfort Control

PdFt = (GPM / (0.658 x Cv ))^2

Cv = 2.5 (1/2 inch VT2212)GPM = 3PdFt = (3 / (0.658 x 2.5))^2

PdFt = 3.3

VT22122.5 Cv (5/16” Port)Close‐off = 40 PSI

Control Valve Pressure Drop

FCU

@ GPM = 3.0

Ball Valve PdFt = 0.1’

Coil PdFt = 5.9’

Control Valve PdFt =  3.3’

Ball Valve PdFt = 0.1’

Total PdFt = 9.4’

÷ 2.33

= 4.0 PSI Diff

Analyze Combined Unit And Valve Package Pressure Drop

Will These Fan Coils Operate As Advertised ?

ChillerChiller

FCU FCUFCUFCU

ChillerChiller

OFF ONONOFF

Water Flow Balance Is A Problem

ChillerChillerFCUFCUFCUFCU

Add Circuit Setters For Manual Balancing

• Manually Adjustable • Fixed CV Orifice – Pressure Drop Measurement• 1/2 Inch CV Rating 2.12 @ Full Open• 3/4 Inch CV Rating 3.90 @ Full Open

• Does Not Adjust to System Pressure Changes• If Pressure Changes – Flow Will Also Change

Manual Circuit Setter

ChillerChillerFCUFCUFCUFCU

Add Cartridge Valves For Automatic Balancing

• Self-Adjusts to System Pressure Changes• Accurate Flow Setting• Range 2 – 80 PSI Differential• Easy Change Cartridge To Change Flow Rate• Extremely Quiet

Automatic Flow Control

Flow Direction

ChillerChiller

FCUFCUFCUFCU

Add Strainers

FCU

ChillerChiller

FCUFCUFCU

3-Way Valve

Primary – Secondary Pumping

FCU

ChillerChiller

FCUFCUFCU

Primary – Secondary Pumping

Valve Package Complexity – vs – Value ?

There Must Be A Better Way

System Design Issues

Chiller / Boiler Equipment Plant Pumps Create Water Pressure Differential Pipes Running To and From Each Unit Valves – On/Off or Modulating Balancing Requires Flow Regulators or Circuit Setters Pressure Relief Valves on Mains Variable Speed Drives on Pumps Controls, DDC, Building Energy Management System Installation Labor:  2/Pipe – vs. – 4/Pipe Direct Return – vs. – Reverse Return Test & Balance is Recommended

The Better Way!

“Each piping system is a network; 

the more extensive the network, the more complex it is to understand,

analyze, or control.   

Thus, a major design objective is to maximizesimplicity.”

2012 ASHRAE HandbookHVAC Systems and Equipment

Chapter 13.11Piping Circuits

ASHRAE Handbook 1996‐2008, Chapter 12

ASHRAE Handbook 2012, Chapter 13

ASHRAE HandbookHVAC Systems and Equipment

2012 ASHRAE HandbookHVAC Systems and Equipment

Chapter 13

One-pipe diverting series circuits –“when coupled with compound pumping systems, series circuits can be applied to

multiple control zones on larger commercial or institutional systems.”

Design Considerations: Piping Circuits -Diverting Series

Primary Circuit Water Flow

Integrated CirculatorCycles on Thermostat Demand

2012 ASHRAE HandbookHVAC Systems and Equipment

Chapter 13

SureFlow by IEC

Multiple Units Share One Pipe

Central Pump Is NOT Responsible For Pressure Drop Of Coil Or Valve Packages

Multiple Loops

Chiller

FANCOIL

FANCOIL

FANCOIL

FANCOIL

Boiler

Two Pipe PerformanceWith Only One Installed Pipe

Chiller

FANCOIL

Boiler

FANCOIL

FANCOIL

FANCOIL

Four Pipe PerformanceWith Only Two Installed Pipes

42ºF 43.8ºF43.9ºF 45.1ºF

42.9ºF

Chiller

Off

52.1ºF

1 Ton13177 t 9954 s

1 Ton

12052 t 9519 s

1 Ton

14424 t 10448 s

1 Ton

SureFlow System Performance

Central Pump Horsepower = __Head x GPM__3960 x Efficiency

Primary Pump

Common Load

Secondary Pump

Chiller‐ Or ‐Heat 

Exchanger

Compound Primary‐Secondary

Loop 1

Chiller

Loop 2

Trunk Main

Service Valves

Balance Valves

Parallel Loops

CHWR

CHWS

Multiple Floors

Building 1 of X Building 2 of X

Central PlantLEED-NC Credit EAc4

Enhanced Refrigerant Management

Campus Chilled Water

SureFlow Water Calculation

Coil Pressure Drop is Redesigned to Match

Circulator Pump Curve

•Single Pipe Chilled Water•Single Pipe Hot Water•2-Pipes for 4-Pipe System•Wet Rotor Circulators•Rating Software

30 Years In Production

Millions In Use

Quiet Operation

Chilled Water CERTIFIED

Non‐Magnetic Impeller

Wet Rotor Cartridge Design

Internal Flow Check Valve

200 PSI Rating

No More Energy Than A Light Bulb

65Watts

SureFlow Circulator – 1/40 HP

SureFlow System Design Software

Rapidly Move Concept to PaperEstimatingBudgetSpeed of Design

Changes Are Made EasilyFlexible DesignFuture Changes Easily AdoptedDue Diligence is Covered

Benefits of SureFlow (Series Decoupled Hydronic Fan Coil Design (ASHRAE))

• Up to 40% reduction in installed pipe length and labor.• Maintenance time and cost is GREATLY reduced.• Pumping horsepower is reduced. Circulators Responsible for coil pressure drop.• Simple and stable on‐off pump operation. Complex modulating controls not required.• No proprietary components. Readily sourced parts.• Refrigerant is contained at the central plant, not distributed throughout the building. 

(LEED Refrigerant Management Credit)• Contractor jobsite coordination is simplified and balancing at the fan coil is eliminated.

Construction Cost Is Lowered. Maintenance Is Reduced. Energy Efficiency Is Enhanced.

A Case Study:

University of North Carolina at Greensboro 

Grogan & Cone Hall

Grogan Hall Stats:

‐ 75,000 Square Feet‐ Constructed in mid‐1960’s‐ Freshman Hall‐ Living and Learning Community‐ 165 Rooms‐ 336 Students‐ Existing 2‐pipe system‐ $2,300,000 Mechanical Renovation Budget (Based on 4‐pipe design)‐ $1,800,000 Mechanical Installed Cost‐ ~22% First Cost Savings‐ ~30% Reduction in Energy (Utilizing Occupancy Based T’Stats) 

Example Riser Diagram

Example Riser Diagram

Vertical Hallway SureFlow Units

Grogan Hall Case Study

University of North Carolina at Greensboro – Cone Hall

‐ Mirror of Grogan plus one additional floor‐ One major difference was that the space between block walls when entering the student room was too small to fit a standard SureFlow Fan Coil Unit. 

‐ Solution: Design a custom SureFlow Fan Coil Unit to fit!

‐ First Cost savings were enough to offset the increased cost of custom SureFlow Fan Coil Units.

SureFlowbyIEC

University of North Carolina at Greensboro – Cone Hall

University of North Carolina at Greensboro – Cone Hall

University of North Carolina at Greensboro – Cone Hall

University of North Carolina at Greensboro – Cone Hall

University of North Carolina at Greensboro – Cone Hall

Added Support For Circulators

Extended Drain Pan

4‐Pipe Valve Package32+ solder joints

SureFlow package16 solder joints

Side by Side Comparison: SureFlow Maintenance Benefits Become Obvious