tankless water heaters an overview of the advantages, opportunities and key design points of this...

Tankless Water Heaters

An overview of the advantages,

opportunities and key design points of

this emerging technology

Rheem Manufacturing Company is a Registered Provider with TheAmerican Institute of Architects Continuing Education Systems.

Creditsearned on completion of this program will be reported to CES Recordsfor AIA members. Certificates of Completion for non-AIA members are available on request.

This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

Questions related to specific materials , methods, and services will beaddressed at the conclusion of this presentation.

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Rheem Manufacturing Company 2008

Learning Objectives

• Understand the history and growth associated with tankless water heaters, and the forces behind this growth.

• Understand the advantages of tankless water heaters, and recognize some of their possible shortcomings.

• Understand that tankless water heaters are not standardized, and how this can play a significant role in design considerations.

• Understand the basics of various installation options and industry accessories that can aid in that installation.

• Understand the basic tankless system sizing concept and how it differs from current methods used to size tank hot water systems.

Now is the time for


But first…….

I’m looking for a color. .

Can you take a fresh look at things?

…the color of a Yield sign.


• It started in the USA with – Edwin Ruud– In 1889 Edwin Rudd was awarded a patent

for his design of a tankless water heater. It had a cast iron body with a copper heat exchanger, and his patent was on a gas actuator valve which turned on the burner when a water faucet was opened

• The American Desire for Storage Tanks– Sometime in the 1920’s the cast iron all

copper heat exchanger design became to expensive to produce

– During that period America was introduced to a galvanized steel tank and then glass lined tanks in the1940’s

– And it’s been that way ever since…until now

History of Tankless Water Heaters

Tankless Global Perspective

Tankless technology – Tankless water heaters are used throughout most of the civilized world except in North America – Leading markets are Japan, China, Australia, Spain & Taiwan

World Market– Total World Water Heater Market is $10.8 billion– Gas tankless market is half or $5.4 billion– Electric Storage is $3.2 billion– Gas Storage is $1.7 billion– Electric tankless is $500 million



• 2009 Total US Market was 325,000 units

– 40% growth between 2003-2005– 50% growth in 2004 alone– 36% growth in 2006– 30% growth in 2007– LP currently accounts for 1/3 of market– Will become 10% or more of the gas market before 2015– Future impact estimated at 30-40% of market – Australian Model: 0 to 30% of market in @7 years

US Market Today

Why Tankless


151 lbs 55 lbs

.62 EF .82 EF

40,000 Btu’s 199,900 Btu’s


Tankless Vs Tank at 90o Rise

67 gal 1st hour(55 gal electric)

222 GPH

13 Ft3 2 Ft3

• Self-modulating or staged burner provide maximum energy efficiency

• No standing pilot – Electric spark ignition

• Temperature rise determines maximum output capacity

((HW outlet) – (CW inlet)) = Temperature rise

Btu input automatically increases as demand for hot water increases

Only operates when there is a demand for hot water

Advanced Technology – Most Models


Tankless Water HeatersWhy Tankless

– Energy Efficient• Up to 15% compared to new 80% efficient commercial tank• Up to 30% compared to new residential tank units• Off unless there is a demand for hot water

– Environmentally Friendly• Low NOx on most

– Precise temperature control• Most high end models• 20 – 50 increments

– Digital displays• Temperature control• Diagnostics and maintenance codes

Tankless Water HeatersWhy Tankless

– Installation flexibility• Indoor, outdoor and direct vent models • Vent horizontally or vertically• Possible lower installed costs

– Space Saving• Install close to end-use• Smaller Footprint – easier to zone

– Unlimited supply of hot water• Primary residential benefit• Manifold up to 20 or more units

– System Redundancy in manifold• If one goes down, the others remain operational



Are Not Standardized


Market Awareness – Know The Product

• Compare units at same temperature rise– Not a 450F rise with a 350 rise– GAMA rates at 770 rise

• Know the minimum fuel pressure required– Varies from 4” to 6” w.c. natural – 8” to 10” w.c. propane

• Know clearance to combustibles– Varies from ½” to 6” or more on the sides– 0” to 2” in rear– Up to 36” to the top and 24” to the front



• Know the minimum activation flow– Varies from .4 to .78 GPM

• Know the high altitude limitations– Does the unit compensate

» If yes – how» What are its limits

• Does the unit offer freeze protection– If yes, what is its low temperature limit

» Important, the units are protected but not the pipes



• Can the unit detect lime buildup– Single unit – Manifold

» Preventive maintenance requirements

• Is bigger better? Saves space, but» Generally lower efficiency» Possible loss of system redundancy

• Right product for the job– Tankless may not be the answer

What About Electric Tankless?

28 to 55 KW to compete with gas models• Home needs additional 120-300 amp supply• Communicating with electric utility is critical

– Failure to can result in equipment failures

Other concerns• Can existing infrastructure handle the load• Excess power for new homes

– Check with utility

Best opportunity at this time • Commercial applications



Tankless products offer design flexibility

Indoor Outdoor Direct Vent


• 3 Primary Tankless Designs

– Indoor power vent (PV)• Primary

– Attics, garages & basements with ample combustion air • Secondary

– Confined spaces without ample combustion air

– Outdoor• Mounted on wall - with or without pipe skirt• Mounted in recessed box

– Indoor direct vent (DV)• Primary

– Indoor confined spaces• Secondary

– Attics, garages & basements with ample combustion air


Options

and

Accessories


Optional Pipe Covers

•For indoor and outdoor models•Used for cosmetic purposes•Can enhance freeze protection

Tankless Water HeatersRecessed Box – Typical Installation

Custom Installation – Enhances Aesthetics



Lowers installation labor and long-term maintenance costs

Easier to install unit when pipe covers and recessed boxes are used

Aids in troubleshooting of units in manifold installations Aids in installation of pressure relief

Aids significantly in de-liming if necessary

Isolation and de-liming valve kits


• For the end-user - not the contractor

• Change temperature settings

• Monitors operation of unit

• Install in a location convenient for the owner

• Can have up to 3 controls per unit on some brands

• Contractor should have one in toolbox for troubleshooting

Remote Controls


Important

Design Considerations


Location is Important

•The shorter the vent, the more economical the installation•Install outside •Install on an adjacent outside wall

•The closer to the fuel supply, the more economical the installation

•Communicate with the fuel supplier•Right meter – right pressure

•Plan for upgrades

•System is only as good as the contractor installing it!

Gas Supply is Critical• Ensure correct pipe size for gas pressure supplied

• Ensure correct meter set by utility

• Ensure proper secondary regulators on >2psi systems

• Post design upgrades– Ensure upgrade is reviewed by all impacted parties

• Engineer, utility, plumbing contractor, gas contractor, etc.



VentingCategory III Appliances

Proprietary or Stainless Steel required(Check manufacturers’ specifications)

Cannot combine vents

B Vent and Galvanized are not acceptable!


Indoor Options•Power Vent or Direct Vent units

Side Wall Vent Termination

•Preferred indoor installation

•Provides lowest indoor installed cost

•Provide downward slope IAW Mfg spec.


Horizontal Venting to Outside Wall

Tankless water heaters are near condensing or condensing, therefore any condensate produced must be handled in accordance with local codes.

Vertical Condensate Trap

Tankless Water HeatersVertical Venting – Least Preferred Option

Outdoor Installations – Usually lowest cost option


Most units are freeze protected with electrical power

• However, plumbing is not•Insulation of pipes and/or heat tracing may be necessary

•Pipe covers or recessed boxes can help


Proper Sizing

It’s GPM - Not GPH!

Important Commercial Sizing Considerations

• Will a storage tank be required– What is the peak demand GPM flow rates

» Watch out for high GPM commercial demands– What is the minimum GPM requirements

» Watch our for low flows without recirculation.

• Can you recirc directly through the tankless system– Will this impact the warranty

• What is the temperature rise required– Restaurant, nursing home, etc.

• Right product for the job– Remember, tankless may not be the answer


Important Residential Sizing Considerations

• What is the most logical GPM usage– Number of showers, shower and appliances,

Roman tub fill, etc.– Residential fixture uses approximately 80% hot water

• What is the temperature rise required– The greater the temperature rise the lower the capacity– Use lowest inlet temperature at peak occupancy/usage– Or, default to January or February inlet water temperature

• Typical residential fixture uses approximately 80% hot water– Refer to GPM charts furnished by manufacturer– Refer to manufacturer’s sizing program if provided


High Efficiency Tanks

Pros – application dependent• Large stored volume• Longer vent options• Lower peak fuel demand

Cons• No system redundancy• Limited hot water supply

Design dependent• Space • Costs

High Efficiency TanklessPros• Unlimited hot water

• Multiple installation options

• Easier to zone

• System redundancy

• Green image & economical

Cons – application dependent• No stored capacity

• Peak fuel demand - retrofit

Design dependent• Space

• Costs


Applications

and

Installations


Residential Applications

•New Construction•Large homes

•Spec homes

•Multi-family

•HUD

•Retrofit•Single family

•Multi-family & HUD

•Mobile Homes

Commercial Applications


Tankless Water HeatersKnown Commercial Applications

• Restaurants• Schools• Churches• Laundromats• Hotels• Multi-family housing• Nursing homes• Prisons• Dormitories• Manufacturing• ?????

Why Foodservice Applications

• Restaurant benefits– Unlimited hot water– Energy Efficient– System redundancy– Saved space

• More production space

• Lower construction costs

• New Construction and Retrofit

• Most all major chains have test installations


Motels and Hotels

• 132 Rooms

– 100 Studios

– 32 One-Bedroom Suites

– Full Bath, Kitchen and dishwasher in each room

• Uses 8 units in manifold


Large Applications

• Removed four 100 gallon 199,000 BTU tanks

• Replaced with twelve

199,900 Btu outdoor units

• Utility bill reduced by 60%

• Expanded facility into old tank location and increased revenue

– 1 x MIC-180 controller


Typical twelve unit outdoor manifold installation



Summary

and

Q&A


•Fastest growing segment ever within the plumbing industry

•Consumer driven, whether an individual or corporation

•Embraced and supported by the natural gas & LP industries

•Proper design and proper installation are key to success

•Positions your firm as a leader in this growing industry

General Summary - Key Points


What is the normal GPM demand of system•Are there any large commercial loads•Most logical residential usage

What is the temperature rise required•Minimum design cold water inlet temperature•Maximum design outlet temperature required

What are the ratings of the tankless unit•GPM output at required temperature rise•Product design specifications•Pump head requirements•Minimum flow activation

Summary – Key Design Considerations


What are the fuel requirements?•Can the unit operate at the available pressure•What are the piping requirements•Communicate with the utility

What are the venting requirements?•Does it require proprietary or Cat III SS vent material•Will it require a condensate trap

Where will it be installed - indoors or outdoors?•Remember..The shorter the vent the more economical the installationThe closer the fuel source the more economical the installation

And finally, is tankless the right product for the job?•More than likely yes, but………..

Summary - Key Design Considerations

Services that may be offered:

• Application and sizing assistance

• PC based sizing program

• Pressure drop and flow rate curves

• Installation specifications

• Installation drawings – some engineering approved

– Manifold, recirculation, combo-heat, etc.

• Product training

Tankless Water HeatersCommunicate With The Manufacturer

tankless water heaters an overview of the advantages, opportunities and key design points of this...

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