electric tankless water heaters - Ron Blank and Associates, Inc.

© Ron Blank & Associates, Inc. 2013
Please note: you will need to complete the conclusion
quiz online at Ronblank.com to receive credit
Developed & Sponsored By
David Seitz, CEO,
Seisco International
888-296-9293
david@deseitz.com
ELECTRIC TANKLESS WATER HEATERS
sei15a
Credit: 1.5 AIA HSW CE Hour
Authored By:
David Seitz – CEO, Seisco International Limited, Inc.
Dr. Tom Harman, Ph.D. – Electrical Engineering, Rice University
Dr. Louis J. Everett, Ph.D. – Mechanical Engineering, Texas A&M University
Eddie Wilcut, MAG – Texas State University
An American Institute of Architects (AIA)
Continuing Education Program
Approved Promotional Statement:
Ron Blank & Associates, Inc. is a registered provider with The American Institute of
Architects Continuing Education System. Credit earned upon completion of this program
will be reported to CES Records for AIA members. Certificates of Completion are
available for all course participants upon completion of the course conclusion quiz with
+80%.
Please view the following slide for more information on Certificates of Completion
through RBA
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 or Ron Blank & Associates, Inc. of any material
of construction or any method or manner of handling, using, distributing, or dealing
in any material or product.
An American Institute of Architects (AIA)
Continuing Education Program
• Course Format: This is a structured, web-based, self study course with a final exam.
• Course Credit: 1.5 AIA Health Safety & Welfare (HSW) CE Hour
• Completion Certificate: A confirmation is sent to you by email and you can print one
upon successful completion of a course or from your RonBlank.com transcript. If you
have any difficulties printing or receiving your Certificate please send requests to
certificate@ronblank.com
• Design professionals, please remember to print or save your certificate of completion
after successfully completing a course conclusion quiz. Email confirmations will be
sent to the email address you have provided in your RonBlank.com account.
Did You Know?
• Did you know that a 2500 square foot home with a total electric service of 150 amps
can easily accommodate a perfectly adequate whole house tankless electric water
heater with no increase in the electrical service requirement and only two additional
electric circuits from the existing service panel?
• Did you know about “interlocks” that block unnecessary competitive electrical loads,
ensuring the adequacy of lower electric service requirements?
• This course will teach you this and much more.
Course Objectives
By completing this course, the design professional will be able to:
1. Explain the Water/Energy Nexus as it relates to water heating.
2. Discuss consumption patterns associated with typical residential hot water
usage.
3. Identify the different classifications of water heater designs currently on
the market.
4. Discuss the benefits and shortcomings associated with each classification
of water heating design.
Course Objectives
By completing this course, the design professional will be able to:
5. Explain the role and effectiveness of Electric Tankless Water Heaters.
6. Discuss the difference between flow control and temperature control as
separate demand water heating activation technologies.
7. Explain the issues of light flicker “power quality” related issues in
evaluating different Electric Tankless models and manufacturers.
8. Discuss the impact of hot water systems on electrical load and peak
demand.
Course Objectives
By completing this course, the design professional will be able to:
9. Describe how properly designed electric tankless water heaters integrate
into a sustainable, low-flow, energy efficient plumbing design.
10. Identify the benefits associated with the use of new low-flow “Electric
Tankless” system technology.
11. Identify the fuel source for each technology and how each is related to
renewable energy.
Course Description
This learning unit will address the benefits of a properly designed and installed
electric tankless water heater and explore how installing electric tankless
water heaters in new construction, in a retrofit situation, or as a companion to
other water heating technologies already in place can offer a reliable, endless
supply of hot water while maximizing both water savings and energy
efficiency.
Understanding the Nexus Between Energy & Water
OBJECTIVE 1
Image source: http://alexansouthwoodblog.com/files/2012/02/energy-lights.jpg/
The Water/Energy Nexus
• According to the American Water Works Association (AWWA), 3.9 trillion
gallons of water are consumed in the United States each month.
• Assuming that it takes, on average, two kilowatt hours to produce and treat
every thousand gallons of water consumed, that equates to 93.6 billion
kilowatt hours of energy needed to produce and treat that water every year.
• Considering all energy sources, an average of 1.3 pounds of CO2 emissions are
released for each kilowatt of energy produced, our current water consumption
results in approximately 122 billion pounds of CO2 emissions every year.
The Water/Energy Nexus
• On average, it takes 2 consumptive gallons of water to produce 1 kilowatt hour
of electricity.
• Annual consumption of electricity in the United States accounts for
approximately 3.9 Trillion Kilowatt Hours (kWh). Assuming that it takes two
gallons of water to produce one kWh of electricity, approximately 17% of all
the water consumed in the United States is used for power production.
The Water/Energy Nexus
• Considering that we consume 93.6 billion kilowatt hours to produce and treat
our water, we can estimate that it take 187 billion gallons of water to produce
that energy.
• In essence, approximately 1 precent of the water we consume each day is
consumed during the production and treatment process.
The Water/Energy Nexus
• Every time you save energy you save water and every time you save water you save
energy!
• Replacing an older 60 Watt light bulb with a new 15 watt CFL will save approximately
98 gallons of water per year.
• Replacing an older high flow toilet with a new High Efficiency Toilet (HET) will save 32
kWh per year.
The Water/Energy Nexus
How Can You Save Water and Energy with an Electric Tankless Water Heater?
1.
By locating the unit closer to the center of fixtures (i.e. clusters) or as a point of use heater, you reduce
the amount of water that would otherwise be wasted in order to get hot water. This saves substantial
amounts of water and energy.
2.
Advanced technologies, which provide for Flow/No Flow Temperature Activated Electric Tankless Water
Heaters allow for the installation of lower flow fixtures that are often not compatible with “MechanicalFlow Dependent” Activated Systems. The use of low flow fixtures saves water, which in turn saves
energy.
3.
Electric Tankless Water Heaters eliminate standby losses and increase the efficiency of the resource
that is being used. An increase in electrical efficiencies saves energy, which in turn saves water.
4.
Electric Tankless Water Heaters can increase the efficiency and/or utility of other systems, including
solar, heat pump water heaters as well as gas when added as an “extender”. By accommodating
smaller hot water draws and boosting temperature only to the level that is needed, the use of Electric
Tankless water heaters as companion devices help to save both water and energy.
REMEMBER, IT TAKES WATER TO GENERATE ELECTRICITY!
IT TAKES ELECTRICITY TO DELIVER WATER!
Understand the true consumption patterns associated
with typical residential hot water usage.
OBJECTIVE 2
Tankless Sizing: Whole Household
• According to the experts, 2.5 gallons of hot water per minute (GPM) will satisfy nearly
every U.S. household.
• The Energy Star program establishes a minimum 2.5 GPM at a 77⁰F rise for tankless
water heaters.
• A typical residential tank water heater provides 50-90 gallons in the first hour and
less during the second hour while it is in the process of heating the newly
introduced cold water to the desired set point.
• 2.5 GPM x 60 minutes is 180 gallons for the first and every hour after, providing
more than double the output of a typical tank water heater.
• Careful fixture sizing and modest lifestyle changes can avoid common oversizing of
tankless water heaters.
Case Study:
• In March of 2003, the National Association of Home Builders (NAHB) Research Center
conducted a “Performance Comparison of Residential Hot Water Systems” for the
National Renewable Energy Laboratories (NREL)
• A copy of this study can be found using the following internet link:
(http://www.nrel.gov/docs/fy03osti/32922.pdf)
• The following slide illustrates that in both a high-flow and low-flow home, a tankless
water heater with the ability to provide 2.5 to 3 GPM at 120⁰F meets nearly 99% of
the demand.
Hot Water Consumption by Flow Rate – Annual
Minutes of Use at Given Flow Rates for High & Low
Volume Homes
Source: National Renewable Energy Laboratory, “Performance Comparison of Residential Hot Water Systems” March 2003
Percent of Total Minutes
over 3 GPM
Low Volume Homes – 0%
High Volume Homes – 3%
Gallons per Minute (GPM) Flow Rates
0.5
Minutes per Year at Flow Rate - Low Volume Home 34,000
Minutes per Year at Flow Rate - High Volume Home 31,800
1.0
3,500
6,000
1.5
2,100
3,000
2.0
2.5
3.0
3.5
305
380 100
5
2,500 2,200 1,000 250
4.0
3
210
4.5
1
80
5.0
0
20
5.5
0
5
6.0
0
6
6+
0
25
*ALL STUDIES SHOW THAT 96 to 98 PERCENT OF ALL RESIDENTIAL HOT WATER USAGE OCCURS AT FLOWS OF 1 GPM OR LESS*
Understand the different classifications of water heater designs
currently on the market
OBJECTIVE 3
Water Heating Classification
• Non-Condensing Gas – Storage Type
Water Heater
• Condensing Gas – Storage Type Water
Heater
• Non-Condensing Gas – Tankless Water
Heater
• Condensing Gas – Tankless Water Heater
• Non-Condensing Gas – Hybrid
• Condensing Gas – Hybrid
• Heat Pump
• Desuperheater
• Geothermal
• Solar
• Electric – Storage Type Water Heater
• Electric Tankless
• Whole House
• Point of Use
• Hydronic Space Heaters
Traditional Tank Water Heaters
• With traditional tank water heaters, incoming cold
water must be heated to a desired temperature and
continuously maintained at that desired
temperature in order to ensure the availability of
hot water when it is needed.
• High flue temperature creates unutilized heat that is
ultimately wasted as it is exhausted thru the flue.
• In order to maintain the desired temperature within
the proper range, the water is first heated to the
temperature set point and then allowed to cool to
the point where the thermostat calls for another
heating cycle. The process of heating and cooling
throughout the day, in the absence of hot water
usage, is a function of standby losses.
• Standby losses related to water and ambient
temperature are dependent upon the insulation
associated with the tank itself. In general, better
insulated tanks will incur less standby losses over a
given period of time.
Source: http://www.diyanswerguy.com
Source: http://eternalwaterheater.com/technology.html
Condensing Gas Storage Water Heaters
• In a condensing storage water heater, a draft-inducing fan pushes
air and fuel into a sealed combustion chamber inside the storage
tank. As the fuel burns, combustion gas is exhausted through a
secondary heat exchanger consisting of coiled stainless steel
tubing which is actually submerged within the tank’s water
supply. Both the combustion chamber and heat exchanger have
large surface areas that help to maximize the heat transfer to the
water.
• With these types of heaters, the heat transfer is so efficient that
the combustion gases actually cool to the point where the water
vapor in the exhaust condenses, releasing its latent heat, which is
also transferred to the stored water. Thru transference of its
latent heat load, the exhaust gas leaving the heater is generally
cool enough to be safely vented through materials such as PVC,
which is far less expensive than stainless steel.
• Some gas condensing storage heater manufacturers claim
efficiencies up to 96% percent.
Picture taken from US EPA Energy Star Website
Gas Tankless Water Heaters
• Modern Gas Tankless Water Heaters were invented with the
intent of eliminating standby losses and ensuring an
unlimited supply of hot water.
• The efficiency of gas tankless water heaters is highly
dependent upon the consumption patterns of the end user
which can result in wide changes in flow rates. In most cases,
higher efficiencies are gained at steady state high flow rates.
Smaller intermittent hot water flows, which are more
common in residential settings, actually serve to reduce
overall efficiency. This is because the unit has to continuously
go thru both the shutdown and startup cycle for each event.
Each time the heater is restarted, the heat exchanger, which
was cooled by fans at shutdown must be reignited. The heat
exchanger must then be reheated before heating any water.
• According to the “Performance Comparison of Residential
Hot Water Systems” conducted by the National Renewable
Energy Laboratory (NREL) in 2003, 97% of all hot water
events in a home with high flow fixtures are less then three
gallons per minute (gpm), while 100% of all hot water in a
home with high flow fixtures are less than three gpm.
Source: http://www.hvacdesmoines.com/tankless_water_heater.html
Gas Tankless Water Heaters
• All gas tankless water heaters require a minimum flow in order to trigger the combustion process.
In many cases, this required flow rate may not be compatible with many of todays low flow
devices that operate at rates of one gallon per minute (GPM) or less.
• The start up and shutdown processes associated with many gas tankless water heaters can
actually trigger a delay in heating the water when there are small durations between hot water
events. This delay in heating can be as long as 10 to 15 seconds. During this time, cold water is
allowed to enter the hot water line, where it is sandwiched between the hot water that was
already in the line and the water that is being heated. This “Cold Water Sandwich” can cause
discomfort to the end user, especially during a shower.
• At every shut down, the unit is cooled. The unit must then be reignited to heat the water. This
results in a delay and wastes energy.
Source: http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=WH
Condensing Gas Tankless Water Heaters
• Condensing Tankless Water Heaters work in a similar
fashion to their storage tank counterparts in that they
employ two heat exchangers. The second heat
exchanger cools the exhaust gases to a point where the
water vapor in the exhaust actually condenses, releasing
its latent heat. As a result, the exhaust gases are
generally much cooler and can therefore be vented using
less expensive materials.
• In most cases, cooling the exhaust gases produces
condensation inside the unit. This condensate can be
very corrosive and the heat exchanger needs to be of
higher quality, non-corrosive materials in order to be
able to withstand the corrosiveness.
• In general, gas condensing tankless water heaters are
more efficient than their non-condensing counterparts.
Source: http://www.navienamerica.com/rearning/
condensing.aspx?skin=condensing
Gas Condensing & Non-Condensing
Hybrids
• Gas hybrids seek to address the concerns associated
with lower flow rates and the cold water sandwich
effect by incorporating a small storage tank which
acts as a hot water buffer.
• Hot water is consistently maintained within the
storage tank to compensate for the delay in heating
caused by the combustion process and by the nontriggering of combustion associated with certain
low flow events.
Source: http://www.hotwater.com/waterheaters/residential/hybrid/next-hybrid-gas/
Heat Pump Water Heaters
• Heat pump water heaters work in the same manner as an air
conditioner, only in the reverse order. Whereas an air
conditioner takes the heat from the compressor and expels
that heat outside the house, a heat pump water heater puts
the heat generated from a compressor into the water in the
tank.
• Refrigerant is vaporized in the heat pump's evaporator and
passed into the compressor. As the pressure of the
refrigerant increases, so does its temperature. The heated
refrigerant runs through a condenser coil within the storage
tank, transferring heat to the water stored there. As the
refrigerant delivers its heat to the water, it cools and
condenses, and then passes through an expansion valve
where the pressure is reduced and the cycle starts over.
• In addition to hot water, the byproduct of a heat pump is cool
air, which can in turn be used to condition surrounding space.
• Heat pump water heaters experience very slow recovery
rates, requiring auxiliary resistance heat, which most often
overrides the heating potential from the heat pump itself.
Source: http://www.heatpump-waterheater.com/
Solar Water Heaters
• Solar Water Heaters seek to harness the sun’s energy
to heat the water and then store it until needed.
• In general, solar water heaters function in one of two
ways, “direct” or “indirect”.
• In a direct system, water is pumped directly thru the
solar collector and into a storage tank.
• In an indirect system, a freeze resistant heat-transfer
fluid is pumped thru the solar collector and passed
thru a heat exchanger where the heat is transferred
to the potable water. These types of systems are
more common in areas where lower temperatures
could cause water in the tubes to freeze, thus causing
damage to the system.
Source: http://www.dudadiesel.com
Electric Storage Type Water Heaters
• Electric Storage Type Water Heaters generally
consist of an upper and lower heating element,
each of which is controlled by its own thermostat,
but interlocked so that only one element at a time
can be turned on. This helps to ensure an even
temperature throughout the tank.
• Like their gas counterparts, electric storage heaters
do incur standby losses, which are directly related
to the insulation associated with a given system.
• Unlike their gas counterparts, electric storage tank
units do not have a non-insulated flue going up thru
the middle of the tank. The gas flues represent a
significant source for heat loss.
• Electric Storage Tank heaters today are very efficient
and can have a thermal efficiency above 95%.
Source: http://omurtlak9.bloguez.com
Electric Tankless Water Heaters
• Advanced tankless water heaters with technologies that are rated to work well with
preheated water help reduce scald potential and work well in many applications for
any other water heating technology on the market such as solar, heat pump and
geothermal heat recovery systems.
• Electric tankless water heaters can generally be broken down into one of four
categories, Whole House, Point of Use, Booster & Extender.
Electric Tankless Water Heaters
“Whole House Units” just like
their gas counterparts, are
capable of meeting all
household needs while
ensuring an endless supply of
hot water.
“Point of Use Heaters” are capable
of serving one or more fixtures
within a general area and
significantly reduce the amount of
time it takes for hot water to arrive
at the fixture, thus providing huge
savings of water and energy. It is
highly important to ensure that the
unit you choose is certified for use
with preheated water.
“Extenders & Boosters” are
intended to raise the water
temperature higher than the
capabilities of the primary source
of hot water supply. It is highly
important to ensure that the unit
you choose is certified for use
with preheated water.
“Extenders and Boosters” allow for the significant increase of the availability of hot water from
another water heating system by maintaining the temperature of PREHEATED WATER to the
desired set point.
Understand the benefits and shortcomings associated with each
classification of water heating design
OBJECTIVE 4
X
X
X
X
X
X
X
X
Geothermal
Easy to Install
Compatible with
Low Flow Fixtures
Available Hot Water
During Loss of Power
Claim to be Up
to 96% Efficient
Availability of Rebates
& Incentives
Desuperheater
X
Solar
X
Gas Tankless
Hybrid
X
Heat Pump
Electric Tankless
Point of
Use/Extenders &
Boosters
Condensing Gas
Tankless
Electric Storage
Inexpensive
Technology
Gas Tankless
Gas Storage
Condensing Gas
Storage
Benefits
X
X
X
X
Benefits
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Electric Tankless
Heat Pump
Solar
X
X
X
X X
X
Increased Efficiency as Compared to
Non-Condensing Gas Storage
X
X
X
X
X
X
X X X
X
Some Models of Gas Condensing
Storage units have high Btu ratings
and will provide endless hot water
X
X
X
X
X
X
Geothermal
Point of
Use/Extenders &
Boosters
X
Desuperheater
Condensing Gas
Tankless
X
Gas Tankless
Hybrid
Gas Tankless
X
Electric Storage
X
Technology
Gas Storage
Condensing Gas
Storage
Benefits
Benefits
Reduced Consumption of Non
Renewable Resources
Unlimited Supply of Hot Water
x
Technology
Electric Tankless
X
X
X
X
Some Models Provide Excellent
Back Up for Other Technologies
X
X
Can Be Centrally Located
X
X
X
Geothermal
Desuperheater
Solar
Heat Pump
Point of
Use/Extenders &
Boosters
Gas Tankless
Condensing Gas
Storage
Electric Storage
Gas Tankless
Hybrid
Benefits
Condensing Gas
Tankless
Claim to be Up to 99% Efficient
Gas Storage
Benefits
Heat Pump
Solar
Desuperheater
Geothermal
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Space Requirement
X
X
X
X
X
X
X
Sediment Accumulation
within Tank
X
X
X
X
X
Reduced Efficiency
Limited Hot Water
Availability
X
X
X
Difficult to Centrally
Locate
Point of
Use/Extenders &
Boosters
X
Gas Tankless
Hybrid
X
X
Condensing Gas
Tankless
X
Standby Losses
Technology
Gas Tankless
Condensing Gas
Storage
X
Gas Storage
Electric Storage
Electric Tankless
Shortcomings
Shortcomings
X
X
X
Most Installations Require
Backups
Slower Recovery Rates
Performance Deviations
dependent upon Climate
X
X
Electric Tankless
Heat Pump
X
X
X
X
X
X X X
X
X
X
X
X X
X
X X
X X
X
X
X
X
Geothermal
X
Desuperheater
X
Solar
X
Point of
Use/Extenders &
Boosters
Gas Tankless
Hybrid
Potential for Scaling
Condensing Gas
Tankless
Higher Upfront Costs
Gas Tankless
X
Condensing Gas
Storage
Uses a 100% NonRenewable Fuel Source
Electric Storage
Technology
Shortcomings
Gas Storage
Shortcomings
X
X
Shortcomings
Incompatibility with Low Flow
Fixtures
X
X
Reduced Efficiency Associated
with Smaller Draws
X
X
Cold Water Sandwich Effect
X
X
Some Models Experience
Power Flicker Issues
X
High Upfront Costs with Whole
House Units
X
X
X
Most Models Not Suitable for
Use with Pre Heated Water
X
X
X
X
X
X
X
Geothermal
Desuperheater
Solar
Heat Pump
Electric Tankless
Point of
Use/Extenders &
Boosters
Gas Tankless
Hybrid
Condensing Gas
Tankless
Gas Tankless
Condensing Gas
Storage
Technology
Gas Storage
Electric Storage
Shortcomings
Understand the applications and effectiveness of electric
tankless water heating.
OBJECTIVE 5
US Coal Reserves and Clean Coal
Electric Generation
The U.S. currently has the largest proven recoverable coal reserves in
the world at 30% of all proven reserves.
• Clean coal electric generation increases jobs, supports local economies and is environmentally
responsible.
• With coal likely to remain one of the nation's lowest-cost electric power sources for the
foreseeable future, the United States Power Industry has pledged a new commitment to even
more use of advanced clean coal technologies.
• The use of technologies that promote the efficient use of electricity produced through clean coal
production also serve to increase jobs, support local economies and promote environmental
responsibility.
Applications and Effectiveness
• The move to renewable energy is a move to electricity as the energy source of choice,
because electricity itself is renewable when generated from wind, hydro, wave power,
solar power, biofuels and other renewable sources.
• Electric Tankless enjoy efficiencies greater than 95%: SAVE ENERGY cleaner,
renewable electric power.
• Electric Tankless can be installed closer to the point of use reducing the wait for hot
water: SAVE WATER & ENERGY.
• Radiant heat loss through the plumbing distribution can be reduced: SAVE ENERGY.
• Opportunities for Off Peak Applications, including Space Heating.
THE DEVIL IS NOT IN THE kW DEMAND,
BUT IN THE CURRENT AND VERY INEFFICIENT
DISTRIBUTION (GRID) SYSTEMS.
Energy Sources & Hot Water: Electric
• Electric tankless can make other technologies more efficient while improving their
performance.
• Ideal companion technology to solar, geothermal, heat pump and desuperheater
heat recovery systems. Provides full utility for systems that normally require a
long recovery period without having to heat more than the water that is actually
used. The only energy required for the additional heat is that which is required to
heat the water to the required temperature, “OFF PEAK”.
• Add to gas tankless to serve low flow draws, including recirculating systems, and
avoid wasted water. Use smaller more efficient gas burner sizing. Save energy
and water with electric tankless/ gas “dual-fuel” hybrid configurations.
• Add to Gas Tankless Units to eliminate the Cold Water Sandwich Effect.
• Significant opportunity for off peak electrical use in hybrid situations, especially in
dual space heating applications.
Energy Sources & Hot Water: Electric
• With all these benefits and nearly 40% of homes heating water electrically, why are electric
tankless not more prevalent, and what improvements have been made?
• The predominant application for these units in the past were mainly “point of use”. These
units were typically considered “Throw Aways”. Most units had very little control, if any,
except for ambient water temperature, flow rate and kW capacity of the heater. These units
were very inexpensive, highly susceptible to scald potential and highly subject to failure.
• Since 1999, many manufacturers have attempted to stack these types of units and use them
as whole house units which resulted in consumer and service provider dissatisfaction.
• Power quality issues resulting from light flicker negatively impacted the electric service
provider who in many cases had to replace transformers to try and satisfy customers.
• Gross misstatements from competing “off shore” manufacturers of gas tankless, particularly
about electrical service requirements and performance which were parroted by national
celebrities added to poor perception.
• Lack of education for both the consumer and installer.
• Disparity in features and quality between different manufacturers of electric tankless
products.
• Misinformation on sizing, particularly with respect to the electric service requirements that
would provide for the use of the appropriate model.
• Electric tankless, when properly sized and designed, provide savings in energy, water and
operating cost. Electricity from renewable is the principle energy source of the future.
Install Cost Comparisons
Whole House Solutions (New Construction)
Heater Type
Cost
Install
Electric Tankless
$900
$450
Electric (60 Gallon)
$350
$450
$1,100
Natural Gas HE (50 Gallon)
T&P
Electric
Gas
Line
Vent
Total
$500
$1,850
$125
$250
$1,175
$450
$125
$250
$500
* $450
$2,875
$675
$450
$125
$250
$250
$250
$2,000
Natural Gas (80 Gallon)
$525
$400
$125
$250
$275
$1,575
Natural Gas HE (80 Gallon)
$725
$450
$125
$250
$275
$2,075
Desuperheater
$500
$450
Heat Pump
$1300
$450
Gas Tankless (199 KBTU)
* Eliminate vent for all outside gas tankless installs
$250
$250
$2000
Operating Cost Comparisons Forecast
Whole House Solutions
Energy Cost
2012
2017
2022
Electricity (kWh)
Gas (CCF)
Propane
Gallons per Day
Water & Sewer (kGal)
$0.12
$1.53
$2.87
65
$6.60
$0.14
$2.25
$4.22
60
$8.03
$0.15
$3.30
$6.20
55
$9.77
Annual Operating Costs
Natural Gas Tank
Natural Gas Tankless*
Propane Tank
Propane Tankless
Electric Tank
Electric Tankless
$423.38
$439.19
$713.87
$639.57
$739.16
$651.77
$538.03
$526.79
$932.25
$831.40
$803.24
$709.13
$683.05
$636.86
$1,214.82
$1,078.99
$812.31
$719.89
Assumed Price
Increase per Year
2012-2022
2.5% per year
8.0% per year
8.0% per year
N/A
4.0% per year
Assumed Efficiency
Rating
50%
90%
50%
70%
80%
98%
*Includes $100 for annual maintenance expense recommended by DOE and Manufacturer
Cost Comparison:
• Electric Tankless are cheaper to install in new construction than gas tankless units and
offer a lower cost alternative for price sensitive retrofit buyers even compared to High
Efficiency tank water heaters.
• Electric tankless is always the preferred solution where butane and propane are used.
(The fuel tank never runs dry, there is no pilot to light, and it results in significant
operating savings)
• With no need for venting and relatively minimal space requirement, electric tankless
water heaters, as previously demonstrated, can be centrally located, thus reducing
the length of the piping runs from the water heater to the fixture. This results in
significant water and energy savings.
Discuss the difference between flow control and temperature
control as separate demand water heating activation
technologies.
OBJECTIVE 6
Demand Water Heating Activation
Technologies
• Flow Activated – Gas Tankless and Most Electrics
• This is the most typical design. These models use a turbine or magnet to
mechanically detect flow/no flow.
• Frequently requires a minimum flow rate of 0.75 GPM or more to activate.
• Delays delivery of hot water – especially with repetitive small draws with gas
tankless due to a safety feature intended to prevent dangerous over-temperature
conditions. This also results in the cold water sandwich effect.
• Temperature Controlled
• Advanced microprocessor design uses multiple temperature sensors and
computer algorithms to detect flow.
• Works with low flow fixtures and high efficiency appliances with virtually no
minimum flow – allows hybrid configurations with preheated water.
Solutions for High Flow Applications
Temperature controlled electric tankless are the ideal technology for High Flow
Applications.
• Multiple units may be used for higher flow applications, such as multi-head body spa
showers, roman style tubs, and unusual usage patterns.
• A unit can also be added to substantially increase the deliverable hot water from the
existing storage tank water heater. The temperature activated unit will only turn on when
the tank temperature drops below the pre-set set point, allowing the tank to deliver its full
capacity with no temperature drop in order to meet the peak demand, then continuing to
deliver hot water at the unit’s rated flow as the tank recovers for normal household
demands.
• Use a high efficiency heat-pump, geothermal or solar tank to maximize energy savings.
• A supercharger can be paired with a storage tank water heater to produce an endless
supply of hot water. A supercharger extends the amount of available water at higher
temperatures because of its ability to work with water that is already preheated.
Understand the light flicker/”power quality” related issues in
evaluating different Electric Tankless models and manufacturers
OBJECTIVE 7
Light Flicker and Power Fluctuation
• There are two proven methods to manage power to maintain flicker and power
quality related issues within the generally accepted standards.
• Multiple and varied kW elements with “Sequential Element Pattern Activation
Control” at predetermined switching frequencies.
• Power-sharing – Controlling the percentage of kW input associated with Multiple
Elements by maintaining a balanced load at switching frequencies in order to
avoid power quality/flicker issues.
• All other methods currently used for modulating power in demand electric water
heaters can create disruption in power quality. This issue and deficiency in these
types of electric tankless water heaters should be taken consideration before such
products are installed.
Power Sharing
PowerShare control technology utilizes computer algorithms and electronic TRIACs to
pulse power on and off, at electric half cycles, to all of the heating elements equally. The
advanced control algorithms used in power sharing provide for high kW load switching at
frequencies that avoid light flicker, while providing uniform temperature modulation
between one to 100% of the heating element’s range.
Staged Activation
The following table represents four independent heating elements operating
continuously at 25% of the heater’s rated output. When the first element is on, the
remaining elements are off, and so forth. This staged activation at electrical half cycles
(8.33 milliseconds) ensures each element is contributing equally to the heat required. It
also maintains the same power level at each cycle avoiding flicker.
PRESS “ENTER” OR “RETURN” TO ACTIVATE THE SEQUENCE
OFF
ON
OFF
ON
ON
OFF
OFF
ON
Element # 1
OFF
ON
OFF
ON
OFF
ON
OFF
ON
Element # 2
OFF
ON
OFF
ON
OFF
ON
OFF
ON
Element # 3
ON
OFF
OFF
ON
OFF
ON
OFF
ON
Element # 4
Benefits of Power Sharing
•
Sequentially activated systems represent the typical control scheme associated with most electric
tankless water heaters. This control scheme sequences elements to full power, one element at a time.
At the end of the hot water event, there is at least one fully powered element on which, at shutdown,
raises the surrounding water temperature to above boiling. These higher temperatures greatly increase
the potential for deposition of mineral deposits. The shutdown temperature on a smaller sheath surface
area operating at 100% will be much higher than the larger sheath surface area operating at 50%. This
unbalanced switching of high kW elements also creates electric power quality issues.
•
By equally and incrementally distributing the power requirements to each element, during most
applications, no single element is on at 100% of its power. Even when there are multiple use events and
all elements are on 100% at some point during use, at shutdown of the hot water events typically only
one application is on at the time the water heater is turned off. Thus because at shutdown it is rare for
the multi-controlled elements to be on at high wattage the latent heat in any element is much lower, and
scaling, which takes place along the heating elements sheath when shutdown temperatures exceed
boiling, is virtually eliminated.
•
The “Electric Tankless Water Heating: Competitive Assessment” conducted by Global Energy Partners,
LLC in 2005 referenced the 1997 monitoring of an electric tankless water heater by the Tennessee Valley
Authority (TVA). Initially, the TVA noted the noticeable blinking of lights that they attributed to harmonic
distortion that resulted from voltage drops from poorly controlled high wattage heating element control.
As a result the manufacturer spent over 3 years developing and testing a new control strategy and
changed out the old control with the new harmonic balancing or “Power Sharing” feature. As a result the
TVA was able to record and verify that the blinking of household lights had been reduced to
“unnoticeable levels.” No additional power quality issues were noted after this modification.
Benefits of Power Sharing
• The larger the heating surface area and the lower the heating surface temperature at
shutdown, the less potential for boiling along the element’s sheath and mineral
deposition.
• Minimizes element operating temperature along the heating element sheath, thus
virtually eliminating mineral deposit precipitation as well as scald potential.
• The shutdown temperature on a smaller sheath surface area operating at 100% will
be much higher than the larger sheath surface area operating at 50%. The higher the
temperature at shutdown, the greater the opportunity for boiling, which can result in
the precipitation of minerals.
Programmed Combination of Multiple
Sized kW Elements
• This technique uses multiple heating elements of differing wattages within the
heating chambers.
• The temperature is modulated by varying the combination of elements that best
match the current demand.
• Drawbacks:
• Non-Standard Elements
• All elements operate at 100% or 0% resulting in boiling and scale buildup
• Reduced element life and higher cost of repair
Sizing Made Simple
System Match – Fixtures, Appliances and Water Heater
• For the whole house you should use the largest kW system that can be
accommodated by the existing residential electrical service.
• Initially, many manufacturers took point of use water heaters and stacked them in
series in attempts to provide a whole house water heating. The smaller diameter
tubing associated with these units result in pressure losses to the hot water supply
that were not only unacceptable to the end user but also were in violation of
plumbing codes.
• Electric tankless units with temperature controlled flow/no flow activation, rather
than mechanical activation, are the only electric tankless units optimized for use with
low flow fixtures and high efficiency appliances.
• Temperature controlled ETWH are the ideal choice when upgrading fixtures and
appliances for energy and water savings.
Flow Restriction:
• When evaluating different Electric Tankless heaters it is highly important to check the
manufacturer’s published pressure drop curves. If you cannot find them, ASK.
• Match rated flow rate with the application to avoid restrictions and user
dissatisfaction. Evaluate pressure drop at desired flow to verify design.
• Many models reduce internal pipe sizing below acceptable levels for whole house
applications, technically violating plumbing code.
Understanding the truth of the real impact, if any, of high wattage electric
tankless water heaters on power quality and fully diversified peak electric
demand
OBJECTIVE 8
Tankless Water Heaters: Determining
The Proper Electric Load Requirements
A simplified view of Electric Tankless load
• According to the NREL and ASHRAE the average home uses between 50-80 gallons of
hot water per day.
• At 1.5 GPM that’s 40 to 60 minutes a day of tankless water heater operation at its
rated load.
• The National Electric Code recognizes "non continuous " loads that do not continue
for more than 3 hours. An electric tankless water heater would be considered as noncontinuous unless used in space heating.
• At a rated load of 117 AMPs for a 28kW (28K/240V) times a 40% load factor for an
occasional use appliance (per NEC) yields a 47 AMP service load requirement for
panel sizing purposes.
Tankless Water Heaters: Electrical Load
Requirements
Typical Residential Load Calculations
Square Feet
5,000
3,500
3,000
2,500
2,000
1,500
Lights
15,000
10,500
9,000
7,500
6,000
4,500
Appliances
22,700
22,700
22,700
22,700
22,700
22,700
ETWH *
32,000
32,000
28,000
28,000
28,000
28,000
Subtotal Load
69,700
65,200
59,700
58,200
56,700
55,200
10 kW@100%
10,000
10,000
10,000
10,000
10,000
10,000
Remainder@40%
23,880
22,080
19,880
19,280
18,680
18,080
A/C
13,568
10,176
10,176
8,480
5,088
5,088
Total Load (kW)
47,448
42,256
40,056
37,760
33,768
33,168
Total Load (A)
198
176
167
157
141
138
Panel Size (A)
200
200
200
200
150
150
* 32,000 Denotes a 32 kW Heater and 28,000 Denotes a 28kW Heater
Maximum Flow Rates KW Design Rating
kW
TEMPERATURE RISE IN °F & RELATED FLOW RATES IN GPM
kW
2.5
3.5
5.0
7.0
9.0
11.0
14.0
16.0
18.0
22.0
28.0
32.0
44.0
25°
0.7
1.0
1.4
1.9
2.4
3.0
3.8
4.3
4.9
6.0
7.6
9.5
11.9
30°
0.6
0.8
1.1
1.6
2.0
2.5
3.2
3.6
4.1
5.0
6.3
8.0
10.0
35°
0.5
0.7
1.0
1.4
1.7
2.1
2.7
3.1
3.5
4.3
5.4
6.8
8.5
40°
0.4
0.6
0.8
1.2
1.5
1.9
2.4
2.7
3.1
3.7
4.8
6.0
7.5
45°
0.4
0.5
0.8
1.1
1.4
1.7
2.1
2.4
2.7
3.3
4.2
5.3
6.6
50°
0.3
0.5
0.7
1.0
1.2
1.5
1.9
2.2
2.4
3.0
3.8
4.8
6.0
60°
0.3
0.4
0.6
0.8
1.0
1.2
1.6
1.8
2.0
2.5
3.2
4.0
5.0
65°
0.3
0.4
0.5
0.7
0.9
1.1
1.5
1.7
1.9
2.3
2.9
3.7
4.6
70°
0.2
0.3
0.5
0.7
0.9
1.1
1.4
1.6
1.7
2.1
2.7
3.4
4.3
77°
0.2
0.3
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.9
2.5
3.1
3.9
Tankless Water Heaters: Electrical Load
& Importance of Interlock Relays
• The use of an interlock is part of the most sophisticated control systems including
those using power sharing. The control automatically activates to disengage
resistance loads such as electric resistance back up to heat pumps, or electric
resistance heating systems, at the commencement of hot water use and enables
these resistance loads after the end of the hot water period. This manner of control
during the hot water usage does not impact the comfort of the user as the time is too
short to significantly impact the room temperature. Interlocks are used most often in
products approved to be used in space heating as well as domestic water heating.
The use of the interlock eliminates competing resistive loads and thus demand and
electric service load requirements.
• Interlock devices associated with water heating should never be used to control airconditioning condensers or heat pumps directly for periods of shutdown of less than
15 minutes.
• Check with your manufacturer to be sure the products have been listed by a
recognized listing agency for both water and space heating.
Electrical Load: Interlock Relay
The following chart represents the service load calculations for a residence having a 200 AMP service
panel. Under the current conditions, the home is equipped with a standard electric resistance
storage tank water heater. Under the proposed “New” system, the home would be equipped with a
32kW Electric Tankless water heater. The service load requirement is increased by the addition of the
electric tankless water heater, however, the total load requirement remains exactly the same. This is
because the addition of an interlock relay ensures that the resistance space heating load and the
Electric Tankless water heater load will NEVER occur at the same time.
Lighting & Outlets
Water Heater
Total all Non HVAC
First 10,000 Watts at 100%
Remainder at 40%
Resistance Space Heating
Total Load Requirement
Recommended Safe Capacity at
80% (Based on 200 AMP Panel)
Interlock Relay Load Interruption
Total Load Requirement
Current Wattage Current AMP New Wattage New AMP
Requirements
Requirements Requirements Requirements
9600
40
9600
40
7200
30
31920
133
52800
220
77520
323
10000
42
10000
42
17040
71
24240
101
7200
30
7200
30
34240
143
41440
173
38400
0
34320
160
143
38400
-7200
34320
160
-30
143
127 Unit Apartment Complex – Melbourne, Florida
Conclusion: Based on independent measured demand and energy consumption.
“Electric Tankless Water Heaters reduces fully diversified peak system electric
demand as well as kW consumption.”
CASE STUDY
Case Study
Florida Power billing history for the Senior Apartment project shows:
• Total of 138,000 sq. ft., with 127 apartments each equipped with an Electric
Tankless Water Heater, single metered to include the 127 apartments, as well as
all common areas and outside lighting.
• Experienced an average maximum peak demand of less than 1kW per apartment
including the load for the common area and restaurants in the total (calculated as
total load divided by the 127 apartments).
Case Study
Billing / Charges History
FPL Account Number: 0228609152 CRANE CREEK APARTMENTS, MELBOURNE, FLA.
Date
Service Days KWH Use Max Demand
Amount
Description
1/23/2007
35
41,280
85
$4,403.88
Electric Bill
12/19/2006
34
38,760
84
$4,412.42
Electric Bill
11/16/2006
28
36,240
102
$4,333.44
Electric Bill
10/18/2006
29
41,280
102
$4,806.34
Electric Bill
9/19/2006
32
51,480
114
$5,868.40
Electric Bill
8/18/2006
29
50,400
122
$5,837.03
Electric Bill
7/20/2006
30
48,720
113
$5,600.68
Electric Bill
The above chart shows the maximum recorded demand for any given month after the
installation of 127 electric tankless water heaters. In no case was the maximum ever greater
than 0.9 kW per unit. Had these been equipped with conventional storage tank heaters, the
kW demand associated with the majority of units in recovery mode at the same time would
have yielded significantly higher kW demand. In most commercial applications, the kW
demand charge is the highest charge generally incurred.
Case Study Conclusion
• Electric Tankless Water Heaters actually reduce the peak load.
• Remember our charts and assumptions:
• 60-80 gallons of hot water per day, 20-30 minutes a day for the tankless, but
nearly 2-4 hours for the tank.
• What does this mean?
• In the late morning, most electric tank water heaters are running at the same
time. These loads stack to create peak demand and continue as these storage
tanks’ water heaters continue to recover, even after everyone gets ready and
leaves for work or school.
• Multiple electric tankless, even on the same transformer will be turning on
and off as each draw occurs with less opportunity for overlap (stacking).
Describe how a properly sized electric tankless water heater
integrates into a sustainable, low-flow, energy efficient
plumbing design.
OBJECTIVE 9
Dedicated Use/Larger Dwellings
Place Electric Tankless heaters to group nearby fixtures and appliances, shorten distance
and size heater by task. Because there is no venting or gas piping, location can be more
creative.
“On Demand" Recirculation
New Installation: Insulated hot water loop with short branch lines to fixtures. Low water
and energy use design.
Demand Recirculation
Retrofit Installation: Use cold water line to complete recirculation loop to farthest
fixture. The use of an electric tankless water heater in this application helps to ensure
heating of the water at the lower flow rates that are common with the recirculating
pump.
Single Unit Configurations
• Shut off valve recommended on inlet for easy servicing.
• T&P valve shown where required by code.
Compatibility: Dual Unit Configuration
• While a whole house Electric Tankless water heater is generally capable of meeting all
household hot water demands, there are times, as can occur with any system, where
simultaneous events may demand more than the unit can effectively deliver. With
temperature activated units, the end user can place two or more units in line as back
up for higher demand hot water events. As with other compatibility situations, water
leaving one unit at the optimal temperature will not trigger activation in the next unit.
• Units should be plumbed in parallel
• Temperature settings should be the same
• Both units should be the same model
DO NOT USE THIS DESIGN WITH ANY TANKLESS ELECTRIC WATER HEATER NOT
“CERTIFIED OR LISTED FOR SAFE USE WITH PREHEATED WATER”
High Volume Endless Hot Water
Install in series with conventional or heat pump tank water heater. Size smaller tank for
peak demand. Save energy while never having to take a cold shower again.
DO NOT USE THIS DESIGN WITH ANY TANKLESS ELECTRIC WATER HEATER NOT
“CERTIFIED OR LISTED FOR SAFE USE WITH PREHEATED WATER”
Compatibility: With Gas, Electric, Geothermal, Solar,
Desuperheater & Heat Pump Storage Water Heaters
• As storage type heaters are depleted of hot water, the rate at which they are able to recover is
defined as the first hour recovery rate. When the amount of water use exceeds the capacity of a
given storage tank, regardless of its heat source, the temperature of the water at the fixture is less
than desired. Also, as effective as today’s alternative heating systems are at transferring heat
energy from natural gas, electricity or other alternative source to the water, there are simply
times where little or no hot water is capable of being produced. During such periods, a
temperature activated electric tankless water heater is capable of boosting the water leaving the
tank to the desired temperature.
• By installing an electric tankless water heater at hot water outlet of the existing tank, you will
extend the capacity of the existing water heater. When water coming from the tank is at the
correct temperature, the temperature “flow/no flow” activation associated with certain advanced
electric tankless heaters ensures that the unit will not turn on or heat water that is already hot.
DO NOT USE THIS DESIGN WITH ANY TANKLESS
ELECTRIC WATER HEATER NOT “CERTIFIED OR
LISTED FOR SAFE USE WITH PREHEATED WATER”
Gas Tankless Companion
Install in series with gas tankless water heater. Use smaller more efficient electric tankless,
allowing the electric tankless unit to handle the smaller GPM draws, including hot water
recirculation. This hybrid configuration reduces the initial equipment costs and potentially any
additional gas service requirements. Furthermore, this installation can eliminate issues such
as the “cold water sandwich effect”.
DO NOT USE THIS DESIGN WITH ANY TANKLESS ELECTRIC WATER HEATER NOT
“CERTIFIED OR LISTED FOR SAFE USE WITH PREHEATED WATER”
Understand the benefits associated with the use of this new
low flow “Electric Tankless” system
OBJECTIVE 10
The Benefits
1.
By locating the unit closer to the fixture, you reduce the amount of water that
must be displaced in order to get hot water.
2.
Temperature Activated Electric Tankless Water Heaters allow for the installation of
lower flow fixtures that are often not compatible with Flow Activated Systems.
The use of low flow fixtures saves water, which in turn saves energy.
3.
Electric Tankless Water Heaters eliminate standby losses and increase the
efficiency of the resource that is being used. Increase in electrical efficiencies
saves energy, which in turn saves water.
4.
Electric Tankless Water Heaters can increase the efficiency of other systems, both
solar and gas when added as a booster. By accommodating smaller hot water
draws and boosting temperature only to the level that is needed, the use of
Electric Tankless water heaters as companion devices help to save both water and
energy.
Understand the fuel source for each technology and how each
is related to renewable energy.
OBJECTIVE 11
Gas Storage & Tankless Water Heaters
• Fuel Source – Natural Gas
• Renewable? NO
• Sustainable? NO
• Alternatives – Bio Gas
• Renewable? Yes
• Sustainable? Yes
http://greenarchitecturenotes.com/2012/02/water-heater-basics-gas-or-electric/
http://www.grainger.com/Grainger/RINNAI-Water-Heater-10D428
Electric Storage, Heat Pump Storage,
Geothermal, Desuperheater & Electric Tankless Water
Heaters
• Fuel Source – Coal Generated Electricity
• Renewable? NO
• Sustainable? NO
• Fuel Source – Heat Recovery
• Renewable? YES
• Sustainable? YES
• Fuel Source – Natural Gas Generated
Electricity
• Renewable? NO
• Sustainable? NO
• Alternatives – Solar, Wind, Hydro, Bio Gas,
Geothermal & Wave Energy
• Renewable? YES
• Sustainable? YES
• Fuel Source – Nuclear Generated Electricity
• Renewable? NO
• Sustainable? YES
Source: http://www.reliable-mechanical.com/green/geothermal.html
Solar Water Heaters
• Fuel Source – Solar Energy
• Renewable? Yes
• Sustainable? Yes
http://www.made-in-china.com/showroom/prcsolar/product-detailyMOmiGuVAPhK/China-Separated-Solar-Water-Heater-FTSL-03-.html
APPENDIX
BASIC WATER HEATING CALCULATIONS
NATIONAL WATER HEATING STATISTICS
US AVERAGE GROUND WATER TEMPERATURES
US NATURAL GAS PRICES
AVAILABILITY OF STATE REBATES AND INCENTIVES
Basic Water Heating Calculations –
Natural Gas
• One British Thermal Unit (Btu) is the amount of energy needed to raise one pound of
water by one degree Fahrenheit.
• One gallon of water weighs 8.33 pounds.
• There are approximately 1,020 Btu in one cubic foot of natural gas.
• One cubic foot of natural gas has the potential to raise the temperature of 10 gallons
of water by approximately 12.24 degrees Fahrenheit.
• The amount of natural gas needed to raise a 50 gallon tank starting at 70 degrees
Fahrenheit to 130 degrees Fahrenheit can be calculated as follows:
(50 x 8.33 x 60) /1020 = 24.5 Cubic Feet
• It is important to remember that the efficiency of the system also plays a very
important role. If the current heating system is only 80% efficient, the amount of
natural gas consumed would actually be increased by 20% to 29.4 cubic feet.
Basic Water Heating Calculations –
Electric
• One British Thermal Unit (Btu) is the amount of energy needed to raise one pound of
water by one degree Fahrenheit.
• One gallon of water weighs 8.33 pounds.
• There are approximately 3412 Btu in one kilowatt hour (kWh) of electricity
• One kWh of electricity has the potential to raise the temperature of 10 gallons of
water by approximately 40.96 degrees Fahrenheit.
• The amount of electricity needed to raise a 50 gallon tank starting at 70 degrees
Fahrenheit to 130 degrees Fahrenheit can be calculated as follows:
(50 x 8.33 x 60) / 3412 = 7.3 kWh
• It is important to remember that the efficiency of the system also plays a very
important role. If the current heating system is only 90% efficient, the amount of
electricity consumed would actually be increased by 10% to 8.03 kWh.
National Averages
According to the Department of Energy, water heating represents 20% of total annual
household energy consumption in the U.S. About 53% of U.S. households use natural
gas water heaters, while 38% use electric and less than 4% use oil.
US Average Groundwater Temperatures
The required temperature rise for a given water heating system is directly related to the
incoming water temperature. Such data is typically available from the local water utility
and is generally included as part of the annual water quality report. Knowledge of the
local water temperature is an important factor in choosing and designing the most
efficient water heating system.
COOL NORTHERN CLIMATE
Cold temperature increases
required heater size by 35% to
50%.
Source: http://www.best-money-saving-tips.com/instant-flow-water-heater.html
Availability & Pricing
The availability of the fuel source can be just as important as any other factor in
choosing and designing a water heating system. In areas such as the Southeastern
portion of the United States where natural gas prices are significantly higher, electric
water heating systems are much more common.
Rebates & Incentives
The availability of rebates and incentives at the federal, state and local levels can significantly reduce
the payback as compared to other seemingly less expensive options.
It is very important that you check with your local utility, as rebates for a variety of systems may be
available.
It is also very important to remember that there is NEVER a payback when installing products that
meet ONLY the “Minimum Efficiency Standards”. In many cases, the addition of rebates to the
potential energy and water savings can result in paybacks of less than one year when compared to
the cost of installing less efficient products.
These states budgeted over 2% of electric revenues for electric energy efficiency
programs in 2010
These states budgeted between 1% and 2% of electric revenues for electric energy
efficiency programs in 2010
These states budgeted between 0.5% and 1% of electric revenues for electric energy
efficiency programs in 2010
These states budgeted less than 0.5% of electric revenues for electric energy efficiency
programs in 2010 or did not provide data
These states have distributed generation (including renewables) programs available
These states have gas programs
Source: US Department of Energy – Federal Energy Management Program
Course Summary
Now, the design professional will be able to:
1. Explain the Water/Energy Nexus as it relates to water heating.
2. Discuss consumption patterns associated with typical residential hot water
usage.
3. Identify the different classifications of water heater designs currently on
the market.
4. Discuss the benefits and shortcomings associated with each classification
of water heating design.
Course Summary
Now, the design professional will be able to:
5. Explain the role and effectiveness of Electric Tankless Water Heaters.
6. Discuss the difference between flow control and temperature control as
separate demand water heating activation technologies.
7. Explain the issues of light flicker “power quality” related issues in
evaluating different Electric Tankless models and manufacturers.
8. Discuss the impact of hot water systems on electrical load and peak
demand.
Course Summary
Now, the design professional will be able to:
9. Describe how properly designed electric tankless water heaters integrate
into a sustainable, low-flow, energy efficient plumbing design.
10. Identify the benefits associated with the use of new low-flow “Electric
Tankless” system technology.
11. Identify the fuel source for each technology and how each is related to
renewable energy.
© Ron Blank & Associates, Inc. 2013
Please note: you will need to complete the conclusion
quiz online at Ronblank.com to receive credit
Developed & Sponsored By
David Seitz, CEO,
Seisco International
888-296-9293
david@deseitz.com
ELECTRIC TANKLESS WATER HEATERS
sei15a
Credit: 1.5 AIA HSW CE Hour
Authored By:
David Seitz – CEO, Seisco International Limited, Inc.
Dr. Tom Harman, Ph.D. – Electrical Engineering, Rice University
Dr. Louis J. Everett, Ph.D. – Mechanical Engineering, Texas A&M University
Eddie Wilcut, MAG – Texas State University