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Overview
of Distributed Resources
by
Dan Rastler, Area Manager Distributed Resources
EPRIsolutions
50 WAYS TO SAVE ENERGY
Roger Engstrom P.E
ITC Energy Division
1-408-518-2133
Extracted from:
The Integrated Design Process
50 Steps to Integrated
Design
By: Clark C. Bisel, P.E.
Flack + Kurtz Consulting Engineers, San Francisco
Trying to develop a definitive list of 50 energy-saving ideas is a little like trying to sum up
the history of the world in 50 words or fewer - you're bound to miss or gloss over more than a few
major points. With that in mind, the following recommendations offer several ideas for
energy-savings technologies and design practices that can be incorporated as part of an overall,
integrated design. This list could just as easily contain 500 or more ideas.
Obviously, no one solution works in every situation. Items must be evaluated based on the
project's specific requirements, and although items are listed under disciplinary heading, each
must be viewed as part of an overall integrated solution.
MECHANICAL SYSTEMS
| 1 |
Complete a General HVAC Systems Evaluation - Energy use is a variable to be quantified in
this process and economics should be carefully considered. This step should not sidestep
additional enhancements. |
| 2 |
Balance Indoor Air Quality against Energy Efficiency - Every design should make indoor air
quality a cornerstone and energy efficiency should be then be considered in light of this factor.
Past energy conservation efforts were often completed without regard for indoor air quality and
the poor results are well documented. Today, an engineer can take advantage of system enhancements
such as heat pipes and run around hydronic heat recovery loops to minimize the impact on energy
use due to current ventilation standards. |
| 3 |
Tailor Project Design Criteria - The definition of general design criteria
(occupancy density, office equipment levels, lighting levels, comfort ranges, etc.) is
often left up to the engineer who bases his design upon other typical buildings in the
marketplace. The use of the building should be understood and design criteria tailored to
specific needs. Actual operating data from similar buildings would be of value in this
process, but it is not generally available. When determining final criteria the engineer
should consider the flexibility to accept future increases in design factors so that the
current design will not be burdened with overly conservative design criteria guidelines.
Have the client review and understand this criteria. |
| 4 |
Use Advanced Design Methods - Use the best design tools available to accurately size
and select system components. Specify equipment that meets these calculations and don't
oversize unless future load increases are part of the design criteria. |
| 5 |
Design for Part-Load Efficiency - Select equipment that remains efficient over a
wide range of load conditions. Equipment will operate at part load a great percentage of
the time. |
| 6 |
Reduce Duct System Pressure Losses - Fan energy to distribute air throughout a
building is significant. Sizing ductwork is often based on rules-of-thumb criteria and
doesn't consider the distribution system as a whole. Computer based duct sizing programs
are becoming widespread and with the integration into CAD systems will become more
important. Optimize balancing damper locations to reduce losses during the design. |
| 7 |
Reduce Duct Thermal Losses - Reduce leakage and thermal losses by specifying low
leakage sealing methods and better insulation of ducts. |
| 8 |
Select Proper Diffusers - Proper air distribution to deliver conditioned air to the
occupied space must be considered. Selection and location of diffuser will both save
energy and improve control of the HVAC system. Select diffusers with high induction ratios,
low-pressure drop, and good partial flow performance. |
| 9 |
Reduce Face Velocity across Coils and Filters - Reducing velocity across coils and
filter will reduce energy directly lost through each component, allow more efficient fan
selections, and reduce acoustical attenuation needs (which impact energy loss). |
| 10 |
Consider Under floor Air Distribution - Once the solution only for computer rooms,
under floor and displacement ventilation techniques are gaining acceptance in other
building types. This solution involves coordination with architectural and structural
design and any analysis should consider the integrated benefits (architectural, power and
telecommunication wiring systems) as decision factors. Under floor systems can operate at
higher supply air temperatures (with a greater number of outdoor air free cooling hours and
chillers operating at higher efficiency when they are needed), with much lower fan energy
requirements. Indoor air quality should also benefit because greater quantities of outdoor
air can be used, and room air distribution can be more uniform. |
| 11 |
Review Chiller Selection - This is evaluated on larger projects, but is often
overlooked with smaller packaged equipment. New equipment is on the market, and even
better equipment under development, for all product sizes that improve performance.
Integrated controls are also available to increase operating flexibility and the ability to
work with other HVAC components. Refrigerant conversion of outdated chillers containing an
environmentally harmful refrigerant needs to be considered for its energy impact. |
| 12 |
Contrast System Efficiency vs. Component Efficiency - The cooling system components
should be optimized together, including chiller, pumping, cooling tower, and distribution.
This approach may be somewhat contrary to utility rebate structures that often focus on
individual components, but should be considered as perhaps the best solution. Analyze the
benefits of increased chilled water and decreased condenser water temperatures. |
| 13 |
Size Multiple Chiller Systems differently - Most installations having a chiller
plant should have multiple, unequal size chillers. This allows for the most efficient
chiller for a given load to operate. |
| 14 |
Consider Desiccant Dehumidification - Such systems can prove effective where latent
loads are significant, such as humid climates or low humidity spaces. Adsorbent enthalpy
wheels, which use exhaust air to dehumidify or cool supply air, or heat regenerated
enthalpy wheels can both significantly reduce electrical power needs for refrigerant-based
dehumidification. |
| 15 |
Consider Gas and Absorption Cooling - While not likely for saving energy, this
approach can reduce energy costs and be cost effective. A heat source, typically from
natural gas, is used for driving the absorption refrigeration process. Direct-fired gas
equipment can be selected to also provide hot water for building heating needs in addition
to chilled water, which improves efficiency and economics. |
| 16 |
Manage loads with Thermal Energy Storage - More of a load management tool, TES
systems shift energy needs from expensive energy cost periods to cheaper time periods.
Depending on the approach this can save energy as well, and from a utility perspective,
will use energy at a time when more efficient generation and transmission is possible. |
| 17 |
Examine Variable-speed Pumping - Primary/secondary pumping systems with variable
speed drives should be considered for use because of their part load energy improvements.
The design should optimize total head loss with the minimum of flow balancing controls.
New opportunities may soon arrive with hydronic system additives to reduce system friction
losses and thus pumping energy. |
| 18 |
Select Heat Exchangers - with low approach temperatures and reduced pressure drops. |
| 19 |
Enhance Heating System Options - Consider condensing boilers, match output
temperatures to the load, use temperature reset strategies, and select equipment with good
part-load ability. Multiple, staged operation should be specified wherever possible. |
| 20 |
Evaluate use of Heat Recovery - Where simultaneous heating and cooling loads occur,
evaluate the use of heat recovery chillers. High ventilation loads would benefit with
air-to-air heat recovery systems for both sensible and latent recovery. |
| 21 |
Use High Efficiency Motors - Premium efficient motors are suggested for all
applications because of energy savings, longer lifetimes, and reduced maintenance. Motors
should be properly sized to reduce part-load losses. |
| 22 |
Use Variable Speed Drives - These systems have significantly advanced over recent
years and offer a proven means of substantially reducing fan and pump energy at part load
conditions. |
| 23 |
Consider Direct Drive Equipment - Losses in the power transmitted from motor to
driven equipment can often be surprising. The engineer should consider direct drive
equipment options and review actual loss factors on other belt or gear driven equipment. |
| 24 |
Employ Direct Digital Controls - Now nearly considered the norm, DDC systems offer
greater accuracy, flexibility, and operator interface than pneumatic systems. On this
latter factor, one can argue that greater operator abilities will reduce maintenance labor
that will more than offset any initial cost premium. Use sensors having the greatest
accuracy to improve energy efficiency. |
| 25 |
Implement Advanced Control Strategies - Greater operating efficiencies result from
use of a DDC system. System optimization, dynamic system control, integrated lighting/HVAC
control, and VAV box airflow tracking are just a few of the available strategies. |
| 26 |
Optimize Domestic Hot Water Heating - Efficient equipment with hot water temperature
matched to the load should be specified. Heat pumps, heat recovery, tankless water heaters,
and combination space heating/water heating systems are options to be considered. |
| 27 |
Install Low flow Plumbing Fixtures - While this might seem like only a water
conservation issue, energy will also be saved because of reduced pumping energy and water
heating use. Standard products are available for a wide-range of applications and are
expected to become standard practice in many areas. |
| 28 |
Reduce Hot Water system Standby Losses - Losses from both distribution piping and
hot water storage tanks can be more than 30% of input heating energy. Tank insulation,
anti-convection valves/heat traps, tank location, and smaller heaters with higher recovery
rates can reduce these loss factors. |
LIGHTING AND POWER DISTRIBUTION
| 29 |
Review Design Criteria - Often the attention paid to illumination criteria is very
minimal without consideration of current IES illumination guidelines, but more typically
use higher, outdated light level standards. IES provides target illumination levels for
various visual tasks that should be considered for specific guidance. |
| 30 |
Exploit Efficient Lamp Selection - Over the past two years the lighting industry has
developed a significant number of new high efficiency lamps and the Federal government has
mandated the future use of these higher efficiency lamps with the Energy Policy Act of
1992. The lighting engineer needs to be aware of these changes and specify the more
efficient source.
Additionally, the design needs to match specific lamp sources to the intended use.
Selecting incandescent lamps for accent lighting or in situations where dimming is
preferred is no longer warranted with today's new compact H.I.D. lamps and dimmable
fluorescent. The past problems with alternate light sources have been rectified with
today's choices and the opportunities associated with lamp selection have been greatly
expanded during this recent revolution in lamp technology. |
| 31 |
Consider Electronic Ballasts - One of the largest improvements for lighting
efficiency over the past few years has been the introduction of a reliable electronic
ballast, which is inherently some 10-20% more efficient than the most efficient magnetic
coil-type ballast. These devices have a higher frequency of lamp excitation and also have
a higher power factor to result in lower energy use. The latest ballasts have
substantially reduced induced harmonics, one of their previous drawbacks. |
| 32 |
Implement Improved Fixture Optics - The opportunities for energy efficiency are
available for both new construction and retrofit projects to take advantage of better
optical control (getting more light on the visual task and reducing glare or spilled light).
Reflectors can now be computer designed and optimized for better efficiency and control.
Louver finish options are also available for visual comfort and integration into a VDT
intensive occupancy. Specifying fluorescent fixtures with heat extraction over the lamp
cavity will also improve fixture efficiency with cooler lamps producing more light output. |
| 33 |
Apply Occupancy Sensors - Now being recognized as an alternative to local light
switching in energy codes, this technique should see much greater use in all types of
commercial construction. Studies have shown savings potential of over 60% depending on
type of occupancy. Recent project experience shows this to be less costly than
programmable control or dual level manual switching. |
| 34 |
Install Efficient Exit Signs - With exit signs of the past typically using 40 watts
and today's available products needing only 1 to 6 watts, the design engineer should be
looking to specify those new options that meet other project criteria. These fixtures are
operational 24 hours a day and when one multiplies the number of exit signs on a project
the savings can be sizable. |
| 35 |
Integrate Daylighting - Often poorly understood by today's architect, the use of
daylighting was a standard design goal in the early 1900's. Building form and orientation
play key roles in effective daylighting integration and should be considered by the
consultant early in the design to assist the architect. Computerized modeling and
visualization tools exist to aid in quantitative and qualitative evaluation. |
| 36 |
Integrate Daylighting Control Strategies - Every building should properly address
control of the electric lighting system in response to natural light from all envelope
sources. Now required by many energy codes on all buildings, the designer needs to be
aware of basic options and effective daylighting performance. Dimmable and stepped
daylighting controls are the two options that take advantage of latest technology.
Continuously dimmed control systems are seen as having the highest level of energy savings
and user acceptance and offer additional energy saving operational strategies, but have
greater initial cost. |
| 37 |
Apply Advanced Task Lighting Products - The inefficient incandescent and
under-counter strip fluorescent fixtures may no longer match occupant needs and are
outdated when compared to the advanced products now available on the market. Issues such
as luminance ratios (critical in VDT environments), ceiling reflectance, glare, and
asymmetrical light distribution are factors to be considered. High performance task lights
with occupancy sensors, compact fluorescent sources, asymmetric reflectors, and electronic
ballasts are now available that reduce energy use by more than 50% when compared to past
options. |
| 38 |
Control Lumen Maintenance - Luminaire light output will reduce through its operating
lifetime, due to factors such as inherent lamp lumen depreciation, luminaire dirt
accumulation, and other factors. Energy savings can be achieved by controlling light
fixture energy, and thus light output, in accordance with these factors. An option when
continuously dimmed ballasts are specified, lumen maintenance controls utilize photocells
to maintain desired illumination levels and adjusts lamp output in response to this
variable life-long output. |
| 39 |
"Tune" Light Level - Typical light fixture layouts are often developed by the
architect to standard spacing and fixture sizes for visual appeal and do not necessarily
correspond to the layout of workstations or the illumination criteria. In response to such
a situation lighting levels can be dimmed or "tuned" to the desired light levels and energy
use reduced. |
| 40 |
Improve Cavity Optics - Effective lighting is dependent on reflected light within
the space. As much as 30% of light in most office environments comes from reflected light
off walls, ceilings, tables, and other furniture. The use of brighter colors and higher
reflective surfaces play a big role in energy savings. The consultant plays an important
role in coordinating these issues with the interior design. |
| 41 |
Utilize Computerized Design Methods - Accurate computer design tools are available
to eliminate past practices of over lighting spaces to compensate for the conservative
standards engineers were forced to accept due to the complexity of any formal analysis
methods. Such tools are best suited for unique or non-typical applications and may not be
needed on standard applications after the engineer has completed a number of runs and has
better experience factors to draw upon. |
| 42 |
Design for Specific Visual Tasks - Typical lighting methodologies often does not
tailor the lighting criteria and the resulting system to the visual task. With the VDT
becoming a standard in all building types, considerations for lower ambient lighting levels
are gaining higher acceptance. Such task/ambient systems reduce overhead general light
levels with a proportionate level of lighting energy reduction and provide supplemental
task illumination only in required areas. Substantial energy is saved at the overhead
system by providing the higher light levels only at the visual task rather than throughout
the entire space. The result is an overall reduction in energy of 20 to 40 percent. |
| 43 |
Choose Higher Building Utilization Voltages - Less energy is lost in distribution
systems with higher system voltages. This factor is often ignored in an effort to minimize
initial construction costs and the long-term impact typically not quantified. |
| 44 |
Improve Power Factor - Power factor is an issue to both the utility and customer.
Poor power factor will result in increased distribution and motor losses that require
additional energy to offset. Motor selection, proper motor sizing, and correction
equipment should be used as appropriate. |
ARCHITECTURAL
- Influence Architectural Decisions
| 45 |
Siting, form, orientation, and landscaping. |
| 46 |
Solar control, shading, and glazing optimization. |
| 47 |
Thermal mass. |
| 48 |
Infiltration control and insulation. |
USER SYSTEMS
| 49 |
Watch out for Office equipment - Electricity use by office equipment is growing
faster than any other category of electricity use in US commercial buildings. Worse, after
all of the efficiency gains are made in mechanical, electrical and architectural design,
buildings will have a majority of their remaining energy used by office equipment.
Purchasing and operating factors are outside of the engineer's design realm, but can still
be influenced. The engineer should advise building users of the impact of such energy use
and also act as an information source on new office equipment now coming on the market.
Reductions of more than 75% are possible with these latest machines and future products may
further economize. |
COMMISSIONING
| 50 |
Commission Building Systems - The building needs to be operated in accordance with
the engineer's design intent. The best system will not perform unless building operators
understand the design and proper operating procedures are followed. Commissioning of
building systems is receiving greater attention by more sophisticated building owners. |
Top of Page
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Upcoming Meetings & Events
Chapter 39
Equinix IBX Data Center Tour
Wednesday, May 21
5:30 pm - 7 pm
Chapter 15
"Why Should I Comply With the Regulations?"
Thursday, May 22
5:30 pm - 7 pm
Sign Up Now for the first CPE Certification Course in the Bay Area in years!
Contact Mark Andresen, 408-342-0790 or Carol Lawrence, AFE Education Chair, 703-234-4066.
CPE Review Course Dates: Mon. – Thurs., May 12-15, 2008
CPE Exam: Fri., May 16, 2008, (8 hour exam)
Location: Peterson Power, 2828 Teagarden Street, San Leandro, CA
Cost: $1,095 for AFE Members; $1,295 for non-members.
Fee covers materials, lunches, and exam fees |
AFE 39 has just joined the US Green
Building Council. www.usgbc.org
MISSION STATEMENT
The U.S. Green Building Council is the nation's foremost coalition
of leaders from across the building industry working to promote
buildings that are environmentally responsible, profitable, and
healthy places to live and work.
More information |
Attention Sponsors
We need several sponsors for
meetings held during the year. Sponsors will receive special
recognition for their participation, including company history and
detailed articles in our newsletter as well as recognition on our
website. If you are interested in being a sponsor, contact Andy Taylor, APT Applied Power
Technologies, Inc., Phone 408-342-0790, Fax 408-342-0797, e-mail
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The Silicon Valley
Chapter is introducing a new service on its web site. We will post job
announcements from our members along with resumes of members seeking
employment. This service is FREE! If you have an open position, or if
you are looking for a new job, send your resume or
announcement to:
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and Associates
P.O. Box 3425
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Phone: 408-993-2086
Fax: 408-996-3581 |
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