LEED, Leadership in Energy and Environmental …franke.uchicago.edu/bigproblems/Energy/BP-Energy-LEED.doc · Web viewAs discussed in Section 2, LEED evaluates the energy performance

Building on LEED Cheng, Esener, King, Larsen

Building On LEED

Improving the Evaluation of Green Buildings

Completed for “Energy & Energy Policy”

Professors George Tolley & Steve Berry

Authors:

Likwan ChengAlp Esener

Kathryn KingErika Larsen

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Executive Summary

LEED (Leadership in Energy and Environmental Design) is a certification and standard-

setting programme designed to improve the environmental sustainability of buildings and

encourage the spread of “Green Buildings.” The success of this program could be

instrumental in achieving US energy and emission reduction goals; buildings contribute a

significant percentage of both US energy and carbon dioxide emissions. The current

version of LEED should be commended for its entrepreneurial progress; it has

undoubtedly contributed to considerable reductions in energy use and emissions.

However, in order for LEED to achieve its full potential and evolve from a benchmark

into a mandate, two key areas of improvement need to be addressed:

Point Alignment: The current version of LEED was designed to be a helpful

benchmark for commissioners who desired to build environmentally sustainable

buildings. It was not intended to be a mandate for all new buildings. As a result,

the point allocations are somewhat unsystematic and not directly correlated to

energy and emission reduction. To ensure that the LEED program achieves the

highest potential environmental improvements, we argue that the current point

system needs to be redesigned such that the points align with actual energy

savings over the lifecycle of the technology. Ultimately, the energy savings and

appropriate point allocation should be calculated and weighted using Life Cycle

Analysis (LCA).

Incorporating Appropriate Standards for Lab Buildings: Currently, analysts

are able to be reasonably accurate in projecting energy performance for most

LEED certified buildings. However, for high energy-use buildings (such as labs),

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the projections do not correlate well with actual performance. Without an

accurate understanding of future performance, it is difficult to design appropriate

LEED standards for high energy buildings. Thus, we recommend efforts to

improve the current knowledge base in relation to Lab buildings. In addition, we

propose establishing a separate point-allocation system specific to lab buildings;

like LEED for average buildings, this system should allocate points based on

actual energy savings.

The current LEED system has achieved a great deal and started us on a path towards

environmental sustainability in buildings. However, it is critical that we continue to

build on this success and allow LEED to have the greatest impact possible.

1.1 Background

LEED was designed by the U.S. Green Building Council (USGBC) in 1998.

Since then it has grown and been modified substantially, with the current version being

labelled LEED 2.2.1 Currently there are over 14,000 projects with LEED certification

and many government agencies have been promoting LEED by implementing its

standards in their own buildings. For example, a recent legislative initiative aims to

require LEED certification in all newly built public schools.

From an environmental standpoint LEED’s goal of reducing the environmental

impact of buildings is extremely important. In North America, where LEED is most

predominant, buildings account for 20% of all energy usage.2 Buildings also account for

72% of all electricity and 54% of all natural gas consumption. They also contribute 37%

1 There also exists a preliminary working paper open to public evaluation for LEED 3.0.2 National Academy of Sciences. (2008)

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of North American carbon dioxide emissions3 To put this into context, this means that US

buildings alone emit more carbon dioxide than any other entire country except China. To

encourage reductions in these environmental impacts of buildings, a system of standards

monitoring energy reduction and increase “greenness” of buildings is necessary. The

introduction of LEED was a first step in developing these standards; it was designed to be

used as a benchmark to be used by building commissioners who wished to be more

environmentally friendly. This effort has been largely successful; by 2006, 642 million

square feet of building space had achieved LEED certification.4 These buildings have

been proven to use significantly less energy and emit less carbon dioxide than non-

certified buildings. However, with success and expansion have come new challenges.

Because LEED is emerging as a mandated industry standard, it must be re-evaluated; its

initial ‘benchmark’ design needs to be adjusted to account for builders who may not be as

motivated. Furthermore, it needs to be made as effective as possible; despite the increase

in LEED certifications, emissions from buildings have, since 1990, continued to grow at

about 2.1% a year.5

1.2 Overview of the LEED Certification Process

LEED (2.2) certification is known as a “menu-based system”. Each building-

commissioner can choose from a list of projects and items (such as installing on-site

renewable energy facilities or improving insulation) to implement in the construction (or

renovation) of the building. The building is then awarded points for these projects/items.

3 Globally this figure is 10%.4 Housing Commission Documents (2007)5 McMahon, J.E (2007)

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With the exception of seven prerequisite requirements (to which no points are awarded

but which must be installed to become LEED certified) and two “special” items (which

have a range of attainable credits) all projects/items are awarded one point. Depending on

the level of points a building receives, varying levels of LEED certification are possible.

These are as follows.6

LEED Certification type Min-Max points necessary

Certified 26-32points

Silver 33-38points

Gold 39-51points

Platinum 52-69points

As the table indicates, there are a total of 69 attainable points. The projects/items from

which these points can be earned are organised into 6 different categories. These are:

1. Sustainable sites (1 prerequisite and 14 possible points): This category is

designed to focus on the sustainability of buildings by reducing the impact of the

buildings to the surrounding environment and by encouraging less

environmentally damaging modes of transport. For example, points are awarded

for locations close to public transportation.

2. Water Efficiency (5 possible points): This category is included to encourage

more efficient use of water and waste treatment. For example, points would be

awarded for installing low-flow water fixtures.

6 “LEED for New Construction and Major Renovation.” (2007)

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3. Energy and Atmosphere (3 prerequisites, 17 possible points, one item with 1-10

point range and one item with 1-3 point range. 4 more items worth 1 point each):

This is the largest and most important category and will be the main focus of this

paper. This category deals with a variety of issues, ranging from improvements in

commissioning (ensuring the building operates as planned), to items dealing with

the way the building optimises its energy. The methodology is two-fold; there are

points awarded for the use of ‘green’ and on-site renewable energies, as well as

points for technologies that reduce emissions and refrigerants.

4. Materials and Resources (1 prerequisite and 13 possible points): This category

deals primarily with building maintenance. Its purpose is to encourage the use of

sustainable and environmentally friendly materials in new constructions and

renovations. For example, points in this category are awarded for providing on-

site recycling facilities.

5. Indoor Environmental Quality (2 prerequisites and 15 possible points): Points

in this category are designed to improve health conditions in the building and to

reduce indoor pollution. Points are awarded for a range of items; these range from

following certain ventilation standards to use of low-emitting substances for

interior design (such as more environmentally friendly forms of paint) to windows

with better exposure to light and outside views.

6. Innovation and Design (5 possible points): This category awards points to

buildings that adhere to certain LEED innovation and design codes, including one

for inclusion of LEED certified member(s) on the building-project team.

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Applicants who wish to become LEED certified can submit an application (by mail or

online) during the design, construction or operational (post-completion) phase of the

building, after which a panel from USGBC will review the building and award it points

accordingly. USGBC requires that the building be inspected at least every 5 years to

maintain certification, but recommends doing so annually.

LEED also has slightly different auxiliary versions for specific types of buildings.

While the general guidelines mentioned above are primarily used for commercial

buildings (which are currently the main LEED adopters). For example, in January 2008

USGBC released a LEED for Homes Rating system that is principally the same as the

general LEED 2.2 but has some modifications to accommodate specific factors relevant

in residential buildings. The modified point system is as follows:7

As shown in the table, two new categories are added: Location and Linkages and

Awareness and Education. Location and Linkages awards points according to where the

house is built and the access it has to other environmentally friendly infrastructures and

7 “LEED for Homes Rating System”. (2008)

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commuter transport and sources. Awareness and Education grants points for educating

tenants and building managers on environmental sustainability.

1.3 Benefits of LEED

LEED has been linked to both economic and environmental benefits. Several

studies have shown that LEED buildings are considered more valuable than non-LEED

buildings, both in actual property and rental prices. LEED buildings are perceived to be

more fashionable among environmentally conscious buyers and renters and this is a

reputation component that can add prestige to the building. Because of this and their

lower energy costs, LEED buildings command a sales premium of $171 per square foot

and a rental premium of $11.28 per square foot when compared to non-LEED. They also

have a 3.8% higher occupancy rate. Perhaps even more importantly, research has also

determined that on average a LEED building saves 25-50% in energy, confirming its

environmentally friendlier status.8 Another possible, albeit less verified, benefit is that

certain materials that award LEED points also tend to increase the life potential of the

building, leading to fewer needs of renovation and maintenance9.

Finally, it has also been claimed that the work and living environment within LEED

buildings is healthier and contributes to higher productivity among individuals inside

it.10.This is difficult to verify; such conditions are rather difficult to isolate from other

variables.. Nonetheless, it can be reasonably assumed that some health benefits are

derived from the reduction in toxic substances throughout the building.

1.4 Costs of LEED

8 Turner, C. and Frankel, M. (2008). CoStar. (2007) 9 “Green Buildings,”.(2007) “LEED Certification for Buildings”.(2007) 10 “LEED Certification Program Leads to Potential Benefits”. (2007)

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Despite these benefits and increasing enthusiasm for LEED, obstacles to LEED

expansion remain. In fact, a large number of LEED projects are frequently abandoned or

halted before LEED certification is awarded. This is due to increased construction and

administrative costs that are difficult to quantify but may discourage potential contractors

and building commissioners from implementing the changes needed to obtain LEED

certification.

There are, primarily, costs for installing and/or constructing the items necessary to

gain LEED points towards certification. Because the LEED system is a point-based

system, these can be a variety of different materials or installations, ranging from types

of paint and insulation to different methods of deriving on-site energy (such as solar

panels). One study estimates these costs to add anywhere between 2-6% to the initial

construction cost of buildings. As mentioned before, LEED buildings sell at a premium

that may more than compensate for these expenses. However, this is only part of the

actual cost of obtaining LEED certification. The less quantifiable costs come from

increased administrative challenges. These can be categorised into commissioning,

documentation/administrative tasks and energy modelling and design. One study

estimates that energy modelling is not a very significant cost (about 0.1% increase in

construction costs), but that the other three categories may increase construction costs by

3-5%11. Below is a table explaining this in better detail:

11 Northbridge Environmental Management Consultants.

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Estimate of percentage cost inc. due to LEED

98%

99%

99%

100%

100%

101%

101%

102%

102%

103%

103%

104%

Low Est. Med. Est High. Est

Energy ModelingDocumentation & FeesComissioningDesignInitial Construction Cost

source: Northbridge Environmental Management Consultants. “Analyzing the Cost of LEED”. < http://www.cleanair-

coolplanet.org/for_communities/LEED_links/AnalyzingtheCostofLEED.pdf>

With these increases in costs, it is ambiguous whether, in terms of a cost-benefit

analysis, LEED is profitable to commission. As we will discuss in more detail later, this

is partially due to LEED’s one item one point structure; items that make more of an

environmental and/or economic impact are generally weighted the same as those who do

not. As a result, the benefit for the building is rather difficult to measure and the lack of a

clear figure and the wide range of equally scored items of different impact tend to cause

prospective commissioners to shy away from attempting to attain LEED certification. In

addition, there is always the issue of discount rates; some of LEED’s benefits, such as

reduced energy bills, accrue in the future. If consumers place too high of a discount rate

on the future, then LEED will not be profitable. Nevertheless, the existing premium for

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http://www.cleanair-coolplanet.org/for_communities/LEED_links/AnalyzingtheCostofLEED.pdf



LEED buildings suggests that either this is not the case, or the reputational benefits are

enough to override the discount.

1.5 Need for Life Cycle Focus

The above sections discussed near-term costs and benefits of LEED. However, to

truly understand the costs and benefits of LEED, it is necessary that we understand to

understand its impact over an entire building life-cycle. This type of analysis is known as

the life-cycle approach (LCA) and looks at the benefits and costs of a LEED building

over its entire lifetime, discounted to reveal its true present value. Using LCA, it is

possible take into account the item’s production, maintenance and other costs.

Discounting it over its lifetime, meanwhile, will allow for better comparison of the item

with other alternative opportunities.12

1.6 Other barriers to LEED expansion/adoption

In addition to the above mentioned cost issues, there are also other barriers that

are not measured in direct financial costs For example, obtaining LEED certification

requires a great deal of time investment. One study concluded that, on average, it takes

300 days for a project to become fully certified. Another found that it took over 225

hours to complete the documentation process. Furthermore, administrative obstacles

depend highly on the level of expertise and can cost up to $70,000 per project. This is

quite a high opportunity cost as it causes the commissioner to forego possibly more

productive activities.13

12 Of course what the exact discount rate is, is often subject to debate. 3% is usually an assumed benchmark for the long term, with current economic and monetary trends determining more short-term rates.13 Northbridge Environmental Management Consultants. Pise, M. N (2006)Johnson, B.T. (2005)

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Another significant barrier is expertise. Unfortunately, given that LEED is only a

10 year old concept, a lack of knowledge regarding its codes and practices exists among

the community of architects, engineers and other contractors for buildings. While this

community often has a reasonable base of knowledge in specific LEED components,

there is a lack of cross-functional expertise and coordination14. Indeed, often a one size

fits-all approach is taken, which does not take into account locational, financial and

dimensional difference between different buildings. In some ways, this problem will be

difficult to rectify without more and better training for professionals involved in the

construction sector. Nevertheless, in terms of LEED implementation, changes can be

made to the current regulations in order to streamline the process. In particular, as

mentioned before, the one-item one-point system is not an effective measure of a

building’s environmental and energy efficiency and does not create the most efficient

incentives for obtaining certification. Furthermore, it bogs down the administrative

process. Instead of focusing on high-impact easy to certify components, the one point

system shifts the focus toward more tedious, less consistent items. These inconsistencies

compound the coordination issues and lower the incentives for learning and adopting the

necessary expertise.

1.7 Overview Summary

Overall, the LEED system has been shown to have several important benefits and has

expanded accordingly. However, the one item-one point system does not efficiently

allocate points. Moreover, direct costs and administrative barriers could be reduced to

facilitate even greater uptake of LEED certification.

14 Johnson, B.T. (2005)

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SECTION 2: POINT REALLOCATION

2.1 Overview

As discussed in section 1, LEED encourages a whole-building approach to

sustainability by awarding points in five key areas of human and environmental health.15

One of the central performance areas of LEED is energy efficiency, which is recognized

in the Energy and Atmosphere (EA) section of the LEED scorecard. However, there

have been critiques of the current LEED EA section16 that recommend LEED points need

to be allocated based on an overall environmental and economic impact instead of just an

energy savings. The objective of this section is to articulate critiques of the LEED point

system and suggest improvements that will include both economic and environmental

impacts.

2.2 EA: Credit 1 Allocation

According to the USGBC, LEED Rating Systems are developed through an open,

consensus-based process led by a group of qualified committees.17 The current rating

system for the EAc1 section for LEED-NC sets a minimum performance requirement,

based on the ASHRAE 90.1-2004 standard. This baseline is then compared to the

percent savings that is calculated using the ASHRAE 90.1-2004 appendix G. This

quantification system of point allocation based energy savings does provide an overall

metric for reducing energy consumption. However, one of the biggest critiques of the

LEED scorecard is that most items are worth one point18, even though some items have a

15 (Energy Star)16 (Tolley and Sabina, April 2009)17 (Energy Star)18 (Chris W. Scheuer , Gregory A. Keoleian)

LEED, 13


greater environmental/economic impact. 19. To illustrate this issue, the following section

will compare two energy savings strategies that incur the same energy efficiencies, but

have very different economic impact.

2.3 Life Cycle Cost Analysis 20

One potential modification of LEED would be to take into account the economic

impact of a given technology over its entire lifecycle. This type of analysis is called Life

Cycle Cost analysis, or LCC. For example, according to Energy Star data, both an

Energy Star programmable thermostat and an oil furnace are predicted to be

approximately 18 percent more efficient than conventional appliances.21 However, these

two technologies should not be assumed to be equal; when their Life Cycle Costs (LCC)

19 (Nancy B. Solomon, AIA)20 (Energy Star Savings Calculator)21 (Energy Star Calculator) The 18% was calculated by finding the percent reduction in BTU’s of both technologies. These numbers are presented on the energy star calculation spreadsheet.

LEED, 14

Initial cost difference $320Life cycle savings $3,955Net life cycle savings (life cycle savings - additional cost) $3,635Simple payback of additional cost (years) 1.0Life cycle energy saved (MMBtu) 319Life cycle air pollution reduction (lbs of CO2) 51,400Air pollution reduction equivalence (number of cars removed from the road for a year) 4Air pollution reduction equivalence (acres of forest) 6Savings as a percent of retail price 330%

Summary of Benefits for a Oil Furnace

Initial cost difference $19Life cycle savings $2,519Net life cycle savings (life cycle savings - additional cost) $2,500Life cycle energy saved (MBTU)-includes both Heating and Cooling 236Simple payback of additional cost (years) 0.1Life cycle air pollution reduction (lbs of CO2) 30,297Air pollution reduction equivalence (number of cars removed from the road for a year) 3Air pollution reduction equivalence (acres of forest) 4Savings as a percent of retail price 2718%

Summary of Benefits for 1 Programmable Thermostat(s)


are compared side by side, there is a significant difference between their economic

impacts.

For example, the Energy Star graphs above calculate the Life Cycle Cost of an

efficient furnace by first, taking the cost difference between an Energy Star furnace and a

conventional furnace. Then, this difference of $320 is discounted by the rate of 4% over a

17-year life span. The final calculation for the Energy Star furnace is a 330%, dollar

savings over the life of the furnace compared to the retail price. On the other hand, with

the thermostat, Energy Star assumed a cost difference of $19 between a conventional

thermostat and an Energy Star thermostat, discounted by the rate of 4% over a 17-year

life span. Ultimately, the Energy Star thermostat, with the same 18% energy savings s

the furnace, results in a 2718% dollar savings in relation to the retail price. Clearly, these

technologies should be provided with different point allocations. However, LEED does

not address economic impacts, only energy savings. For LEED to take a more holistic

approach the USGBC committees need to weight technologies according to the economic

impact they produce. Additionally, a more holistic point structure would not only include

the economic impacts but also incorporate energy costs consumed during the life of a

technology.

2.4 Benefits of Point allocation based on Life Cycle Analysis

A second critique of the LEED EA point system is that the cost savings formula does not

account for the real energy costs of a given technology; it fails to incorporate the energy

costs of production, transportation, and other steps in the supply chain. The

quantification method for this is called Life Cycle Analysis (LCA). According to

Boustead Consulting, the concept of LCA originated in the 1960’s when architects

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realized the importance of examining the performance of industrial systems through their

entire life cycle, not just during operation.22 The analysis of a building’s energy life cycle

begins with calculating the energy needed to extract raw materials from the earth, energy

needed to transport the materials, energy needed for operation, and finally the energy

needed to dispose of the materials. This has also been referred to as “cradle to grave”

analysis.23 LCA is becoming nationally and internationally more recognized as a best

practice model for understanding the total environmental impact of building construction.

The Environmental Protection Agency (EPA), along with other international

leaders in energy reduction, has recently placed heavy emphasis on refining and requiring

a decision-making tool based on LCA.24 The reason for this emphasis is that an

implemented building technology, with the intention to reduce energy consumption,

could potentially consume more energy through its entire life cycle then it will reduce

during its operational life. If an analyst is well trained and using up to date software,

LCA is a very reliable method for architects and builders to identify and manage the total

environmental impact of implementing energy technologies, and is thus a good way to

assign LEED points in the EAc1 section.

LCA aligns well with sustainability because it addresses one of the main goals of

LEED; reduce a building’s total environmental impact. It also would serve a key role in

increasing awareness of the true impacts of different technologies. If the LEED EA point

system was made more equitable by using output from interpretation of LCA data, the

point system will encourage engineers to gain knowledge about what designs are worth

22 http://www.boustead-consulting.co.uk/introduc.htm23 (Barbara Nebel)24 (Kenneth R. Stone)

LEED, 16


replicating in the long run based how much economic and environmental life cycle

impact they will have during their life, not just while they are in operation. Since

engineers’ recommendations are incorporated into all phases of a building’s lifecycle, not

just the design, this knowledge would have significant impact.25 Another benefit of LCA

is it isolates the technologies that will have the highest Energy Return on Energy Invested

(EROEI). EROEI is the ratio of the amount of usable energy gained from a technology

compared to the amount of energy expended to obtain that technology. To increase its

impact and continue its leadership in the green community, LEED should weight points

based on LCA analysis, incorporating the life cycle energy consumption of new

technologies into their point structure.

2.4 Methods of Calculating LCA

There are many high quality Life Cycle Analysis software applications. However,

‘GABI 4’ is one of the most used and recognized applications.26 Other tools include:

Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts

(TRACI), developed by EPA27 and Building for Economic and Environmental

Sustainability (BEES) developed by the U.S. federal government.28 All of these

computer applications are able to calculate many different environmental and economic

outcomes from the entire life cycle of the materials used in green buildings (see figures

1,2,&3). The software’s data base includes most common building technologies,

however if the data you need is not in the data base it can be entered in the form of an

excel spreadsheet. Currently the biggest drawback of LCA is a lack of databases for the

25 (Scot W. Horst1, Wayne B. Trusty, MA2)26 (Michael Ivanovich)27 (S. Shyam Sunder, Barbara C. Lippiatt and Jennifer F. Helgeson )28 (Barbara lippiatt / NIST)

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most cutting edge technologies, in addition to the required training necessary for

professionals to interpret the findings and apply them appropriately. Proponents of LEED

should work to advocate for investment in the development of these databases; greater

amounts of knowledge incorporated into LCA analysis will eventually translate into

greater environmental gains from LEED certification.

2.5 Case Study: LCA costs for a Solar Panel

As mentioned in previous section, the current LEED point system only includes

the energy savings during the operation of the technology, not during the entire life cycle.

According to a resident case study, a Photovoltaic (PV) Solar Panel of 2.5 Kw is

estimated to yield a 10% annual energy savings for a house of approximately 2500 square

feet.29 However, this energy savings does not take into account potential energy used or

saved during manufacturing and transportation, as compared to alternative sources of

energy. An example of an LCA GABI software quantification of energy used, based on

national averages, for the Balance of system (BOS)30 of PV solar panel is shown in Fig. 1.

From the chart we see that a total of 542 MJ/mw of energy are used during the Life Cycle

of the BOS of a PV. For LEED to take the next steps for implementing a holistic point

system the energy needed to create, transport and disposal of the materials should be

subtracted from the predicted energy performance used in calculating the original savings

analysis.

2.6 Costs of implementing a more sophisticated point system

29 (Energy Efficiency Contractor)

30 (Vasilis M. Fthenakis and Hyung-Chul Kim)

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Although LCA would contribute significantly to the efficiency of the LEED point

allocation, it comes with its on set of costs. One of these costs is complexity. A more

sophisticated LEED point system yields a more accurate environmental impact, but it

may not be easily understood by architects and homeowners. Moreover, there will be

costs involved in building the required knowledge base. As mentioned above, the biggest

drawback of LCA is a lack of databases for the most cutting-edge technologies. In

addition, it will be necessary to invest in training to enable professionals to interpret the

findings and apply them appropriately. However, if USGBC committees are able to

conduct a complete Economic and Environmental impact analysis and equate the LEED

point system to these quantifications, USGBC will move much closer to a fully

sustainable green building approach. Ultimately, the benefits of this approach should

extend far beyond the initial cost.

2.7 Recommendation Summary

USGBC is continually working toward improving their point system to reflect

relevant environmental impacts. However, the LEED points in the EA section lack net

energy reductions and fail to incorporate economic impacts that accrue over the

technology life cycle. The next step is for USGBC to create benchmarks based on LCC

and LCA that can be applied as a new point LEED structure.

LEED, 19


LEED, 20

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Figure 3

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Figure 4: Assumptions for both graphs:

Life Span of 17 years.

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Discount RateCommercial and Residential Discount Rate (real) 4% A real discount rate of 4 percent is assumed, which is

roughly equivalent to the nominal discount rate of 7 percent (4 percent real discount rate + 3 percent inflation

Energy ConversionsBtus per Gallon of #2 oil 139,000 Btu/gal EIA 2006Btu per Therm of Gas 100,000 Btu/Therm LBNL 2004

Energy Prices2006 Residential Price of # 2 Oil $2.41 $/gal EIA 20072006 Commercial Price of # 2 Oil $2.04 $/gal EIA 20072006 Residential Gas Price $1.34 $/therm EIA 20072006 Commercial Gas Price $1.17 $/therm EIA 2007

Carbon Dioxide Emissions FactorsOil CO2 Emission Factor 161.27 lbs CO2/MMBtu EPA 2007Gas CO2 Factor 116.97 lbs CO2/MMBtu EPA 2007

Carbon Dioxide EquivalentsAnnual CO2 sequestration per forested acre 8,066 lbs CO2/year EPA 2004Annual CO2 emissions for "average" passenger car 11,470 lbs CO2/year EPA 2004


SECTION 3: LEED AND LABORATORY BUILDINGS; QUANTIFYING THE

IMPACTS OF LAB OPERATIONS ON BUILDING ENERGY PERFORMANCE

3.1 Background: Energy Performance of LEED Buildings

As discussed throughout this paper, a central goal of the LEED system is to

achieve energy savings. However, optimal energy savings are not achieved by merely

installing an energy-efficient technology. In the life-cycle energy consumption of a

building, the operation of the building occupies a dominant portion.31 As a result, the

success of LEED ultimately relies on the energy performance of the building after LEED

certification. While LEED certification is based on a point scheme, the effectiveness of

LEED as a system should not be judged by the amount of points achieved, but by the

actual energy performance of LEED buildings in comparison to average buildings of the

same type. Indeed, at first glance, LEED performs quite well. In 2008, the first

comprehensive post-occupancy assessment of LEED-certified buildings was published;32

this study, together with an earlier, smaller-scale similar study, has provided the first

evidence of LEED building performance.33 They show that LEED buildings of median

energy usage—offices, schools, libraries, etc.—are 25% more energy efficient than non-

LEED buildings of the same types. These studies also show that, on average, the actual

energy performances of LEED buildings are highly correlated with their design

projections. In Fig. 1, the energy usage intensities of LEED buildings from Diamond et al

31 Scheuer et al, 200332 Turner and Frankel, 200833 Diamond et al, 2006

LEED, 23


(2006) and Tuner and Frankel (2008) are shown; for median energy usage buildings,

good correlations are shown between design projections and actual measurements.

Nevertheless, despite the success of LEED with median energy usage buildings,

these studies also reveal significant discrepancies between design and actual

performances in high energy usage buildings, predominantly scientific laboratories. The

actual energy consumptions of these buildings generally exceed design projections.

Furthermore, their performances show significant inconsistency. In Fig. 1, the energy

performance data of laboratory buildings from Diamond et al (2006) and Tuner and

Frankel (2008) are also shown. Ultimately, its clear that the understanding in this area is

lacking.

3.2 Current Knowledge in Laboratory Building Energy Performance

The causes of the ‘poor’ performances in laboratory buildings are presently not

fully understood. In presenting their data, Tuner and Frankel (2008) observe that “the

characteristics [of laboratory buildings] are not well understood by the design

community,” and this understanding “has significant implications on [building] life-cycle

cost analysis.” They conclude rightly that “there is a need for significant additional

research into the performance characteristics of [laboratory] buildings”

This need is made even more significant when the high quantities of energy

consumption of laboratories are considered. An extensive study of laboratory energy

consumptions, covering 4 million sq. ft. of laboratory spaces on five campuses of the

University of California system, indicates that laboratories on average use 5 times more

LEED, 24


electricity and 5 times more fuel than non-laboratory spaces.34 The majority of recent

literature concurs with this estimation; in particular, the design guide by National

Institute of Building Sciences estimates that laboratory buildings consume 4 to 8 times

more energy than non-laboratory buildings.

This need to increase understanding of lab building performance is also made

urgent by the present boom in green laboratory constructions. Driven by increased

consciousness to energy conservation and legislative mandates, and coinciding with

intensified investments in research facilities by research universities, the number of new

construction (NC) LEED laboratories has significantly increased in the last few years.

3.3 Current Status of LEED for Laboratory Buildings

As discussed in Section 2, LEED evaluates the energy performance of a building

quantitatively. The method sets a minimum performance requirement, or baseline, based

on the energy use intensity (EUI) of the ASHRAE 90.1-2004 standard for the energy-

efficient design of buildings. Then, the provision in ASHRAE 90.1-2004 Appendix G is

used to demonstrate a percentage improvement over the baseline performance for LEED-

NC, Energy and Atmosphere Credit 1, optimize energy performance (EAc1). This

process is used in both projecting building performance during design and in evaluating

actual performance after construction. During design, EAc1 credits are awarded based on

the percentage of energy savings calculated from a required computer simulation.35

34 Mills et al, 199635 The simulation is an hour-by-hour whole building energy analysis using approved software.

LEED, 25


Given the differences in energy usage, it was recognized that the LEED scheme

for non-laboratory buildings is not suitable for laboratories. In 2005, a task force was

charged to create a LEED system specifically for laboratory buildings, called LEED

Application Guide for Laboratories (LEED-AGL). Nevertheless, progress has been

limited. As of May 2008, these guidelines are yet to be released for implementation.

Presently, practitioners rely on Laboratory for the Twenty-First Century (Labs21), an

alternative energy performance benchmark scheme developed by the EPA, for laboratory

design (US EPA, 2000). However, there is no official relationship between LEED and

Labs21; these can lead to coordination issues and sub-optimal evaluation.

3.3 Objective of Study: Connecting Operations and Whole-Building Consumption

To help understand the energy performance of laboratory buildings, we examine

the critical, but so far unexamined, connection between laboratory operations and energy

consumption at the whole-building level. Specifically, we ask the question: To what

extent do variations in laboratory operations (in the form of instrument plug loads)

account for, and therefore potentially explain, the observed variations in laboratory

building energy usage? Ultimately, answering this question will help to quantify the

contribution of laboratory operations to whole-building energy usage. It will help the

design community develop appropriate design strategies and measurement

methodologies, while also facilitating the ongoing development of LEED-AGL. Finally,

it will be critical in helping researchers, technicians, and laboratory building managers to

identify energy saving opportunities and adapt energy efficient work practices.

LEED, 26


3.4 Methods & Data Analysis; Composition and Characteristics of Laboratory

Energy Loads

In order to evaluate LEED performance in lab buildings, it is first necessary to

understand the energy usage, or “energy load” of this type of building. The energy load

of a laboratory building is composed of the building HVAC system, cooling, heating,

space lighting, and instrument plug and process loads. Compared to non-laboratory

commercial buildings, the HVAC load is significantly larger due to health and safety

regulations, and the plug-in and process loads are also significantly larger because of

large power requirements of experimental research equipments. Equally importantly,

laboratory operations do not follow regular schedules like those in offices and homes;

they are instead determined by the need of specific experiments being conducted. As a

result, compared to non-laboratory commercial buildings, energy consumption of

laboratory buildings are often both highly irregular and highly intense.

3.5 Methods & Data Analysis: “Bottom-Up” Approach for Evaluating Laboratory

Energy Usage

Given that buildings are integrated systems, building energy consumptions should

be evaluated at the whole-building level. However, to understand the underlying causes

of energy consumptions, one must begin by looking at individual plug sources, and how

they interact with the building system level. Therefore, a bottom-up model of energy

usage is needed.

LEED, 27


For this evaluation, we adopt the bottom-up approach of Tanimoto et al (2008). In

this approach, bottom-level detailed data on occupant activities, appliances usages and

their electric power ratings, and schedule of usage are collected or estimated. These data

are then used as inputs to a model which calculates the overall energy usage at the whole

building level. This approach is validated in that the modeled energy consumptions are in

good agreement with actual metered values.

3.6 Methods & Data Analysis: Data Collection

Data on laboratory instrument types and their electrical power ratings in operation

and stand-by modes was collected from several chemistry, condensed-matter physics, and

molecular biology research laboratories at Gordon Center in May 2008. Information of

laboratory spaces and working schedules was also collected from Gordon Center.

Additional instrument information was obtained from manufacture specification sheets.

3.7 Methods & Data Analysis: Model of an “Average” Laboratory

In order to create the model of a broadly representative, sufficiently complex and

energy dependent laboratory, we have chosen to “average” a more energy intensive

surface physics laboratory and a less energy intensive analytical chemistry laboratory.

The main instruments in the surface physics laboratory are the ultra-high vacuum

chamber (UHV) system with associated molecular beam deposition devices. The main

instruments in the analytical chemistry laboratory are the spectrometers and

chromatographers. The “average” laboratory is created by taking the means instrument

LEED, 28


loads of the two laboratories; common instruments, such as ultrasonic cleaner, are then

added into the equation..

The instrument details and their loads at the high and low usage conditions are

shown in Table 3.2. The EUI of the average laboratory under high and low usage

conditions are calculated by dividing the loads by the floor area of the laboratory, of

1,000 sq. ft.; these values are 38.4 and 13.1 kWh/sf (per year), respectively.

3.8 Methods & Data Analysis: Energy Analysis

We must now evaluate how the instrument plug loads summed up from Table 3.1 interact

with the building HVAC. In order to calculate this interaction, we rely on the energy

analysis presented for a typical Labs21 laboratory.36 Regardless of the climate zone of a

building, laboratory plug and process loads add to building HVAC loads. To evaluate

building system loads, we use data extracted from this Labs21 model to create a plug

intensity vs. building system intensity plot (Fig. 3.2); a linear fit to this plot gives the

equation y = 0.18x + 26.1, where x is the plug intensity and y is the system intensity.37

This equation provides the dependence of system intensity on the plug intensity, in

kWh/sf (per year). We use this relation to calculate the system EUI corresponding to the

high and low instrument plug intensities for the modeled average laboratory.

Subsequently, a range for the total EUI (instrument plus building system) is obtained

between the high and low usage periods; this range is 55.6 kWh/sf, or 190 kBtu/sf. The

range in this value represents the intrinsic uncertainty in total laboratory EUI due to

36 Enermodal Engineering and NREL, 200337 Enermodal Engineering and NREL, 2003

LEED, 29


variations in laboratory operations intensities; it is inherent to the nature of the usual

practice of scientific research. This range is graphically imposed in dash lines in the

design-vs.-measurement intensity plot in Fig. 3.1.

3.9 Discussion: Implications in Energy Design Strategies and Performance

Interpretation

This study confirms and quantifies the inherent nature of irregular energy usage in

laboratory research operations. Its finding should have significant implications in

laboratory energy performance in both the design and the evaluation phases. For the

design phase, the characteristic size of the EUI variation, of 190 kBtu/sf as determined for

our model, implies that the traditional ‘right sizing’ approach to energy savings

commonly used for office and apartment buildings is inadequate for laboratory design.

Instead, emphasis must be placed on implementing variable building system capabilities

that are capable of adjusting to the irregular nature of research operations intensities.

On the other hand, for building energy performance evaluation, evaluators must

recognize that the apparent discrepancies between measured EUI and design-projected

EUI might be due to irregularities in laboratory operations intensities and should not

necessarily be attributed to design failure. It is important to note that, in Fig. 3.1, if the

empirical uncertainty from the non-laboratory building data (where statistics are

sufficient) is added to the operations-induced uncertainties (y = ±95), most of the

laboratory data points would indeed fall within this uncertainty from the y = x line.

LEED, 30


In addition to instrument loads, variations in other laboratory end-use loads not

considered in this analysis may also contribute, although usually to a less extent, to

changes in whole-building EUI; these include lighting schedule, occupancy, and the habit

of operating the laboratory fume hood (discussed in further detail below). Ultimately,

any evaluation mechanism must be able to adjust to variations in instrument usage.

3.10 Discussion: Savings-Weighted LEED Point Allocation; A Case Study of the

Fume Hood

The present study also has implications in rational LEED point allocation. To encourage

variable building system measures that can adjust to frequent irregular activity demands,

LEED points should be awarded to implementing adjustable HVAC savings measures.

To illustrate this point, we use the example of the fume hood, a dominant HVAC

component that directly interfaces with laboratory spaces and activities. On average, a

fume hood consumes over 450 MBtu of energy (2.5 times that of a home) and has an

annual operations cost of over $5,000.38 Already, high-performance fume hood has been

identified as an item for LEED point allocation. However, present LEED schemes fall

short of correlating point quantities to the amounts of energy saved by a measure, an area

in which improvement has been exhibited.39

In general, fume hood energy savings are achieved by reducing air flow volume during

inactive periods, which statistically account for most of the hours of a day. Two EPA

Labs21-recommended measures serve this purpose—(1) closing down hood sash window

38 Mills et al 199639 Tolley and Shaikh, 2008

LEED, 31


with an automatic sash controller (ASC), and (2) reducing hood fan power with a variable

air volume (VAV) system. Fig. 3.3a and 3.3b show fume hood energy usages as a

function of sash opening height at constant fan powers, and energy usages as a function

of fan power at constant sash heights. These calculations are done using a model

developed by Lawrence Berkeley National Laboratory and are for the climate of

Chicago.40 Based on Fig. 3.3a and 3.3b, energy savings from reducing sash height from 6

inch to 0.25 inch using ASC and from reducing fan power from 1.8 W/cfm to 0.8 W/cfm

using VAV are calculated and shown in Table 2. Also shown is a comparative life-cycle

economic cost-benefits analysis for ASC and VAV.

As a further demonstration of this principle, Table 2 also illustrates saving-weighted

LEED point allocations proportional to the size of benefits. These point allocations are

done at three, increasingly broad economic levels—(1) based on energy savings only, (2)

based on net cost benefits, and (3) based on net cost benefits plus the benefits of

reductions in carbon emission. In this particular example, if we were calculating LEED

points based on energy savings alone, reducing the sash height alone would be worth 1

point, while reducing the fan power would be worth .4 points. However, if we took into

account net cost benefits and the reductions in carbon emissions, reduction in fan power

would only be worth 1/10 of the 1 point that should be awarded to reducing the sash

height. Hence, this savings-weighted point allocation method inherently spells out the

relative efficiencies among the eligible measures. It serves to steer consumers toward the

best measure and still retains a reasonable simplicity for practical implementation.

40 Mills and Sartor, 2006

LEED, 32


In summary, using instrument power and laboratory operations data, we have shown that

variations in laboratory operations induce an uncertainty in whole-building energy usage

intensity that is of the order of 200 kBtu/sf. This finding implies the importance of

employing variable system measures for energy savings. The principle of savings-

weighted LEED point allocations for variable savings measures has also been

demonstrated with the case of fume hood.

CONCLUSION

The LEED standard has accomplished a great deal; despite the oft-heard criticisms the

pioneers of LEED should be commended for their efforts to develop a standardized

evaluation mechanism for green buildings. Undoubtedly, these efforts have led to

dramatic reduction in energy usage and emissions within certified buildings.

Nevertheless, as LEED evolves from a general benchmark into a more widespread

mandate, two critical changes should be made: 1) the point system should take into

account relative energy savings across the entire life cycle of a given technology and 2) a

modified LEED evaluation system should be developed for energy-intensive/lab

buildings; this system should be developed using savings weighted point allocations that

award points for variable savings measures. One issue not directly addressed in our

paper, but that still needs a great deal of consideration, is quantifying and weighting

LEED points based on green house gas emission from both building materials and new

technologies. Ultimately, if these recommendations are adopted, LEED certification will

allow commissioners around the world to more efficiently build toward a better future.

LEED, 33


ACKNOWLEDGEMENT

We thank C. Turner of the New Buildings Institute for providing data referenced in

Turner and Frankel (2008).

SECTION 1 REFERENCES

Section 1 References

CoStar (2007). “Commercial Real Estate and the Environment”. <http://www.costar.com/partners/costar-green-study.pdf >

Johnson, B.T. (2005). “Barriers to Certification for LEED Registered Project. <http://www.ibe.colostate.edu/projects/theses/johnson_thesis.pdf

(2007) “Green Buildings, LEED certification proves cost-effective, ready to expand”. <http://sbt.siemens.com/customerlounge/whatsnew/press.249.asp>

(2007) “LEED Certification for Buildings”. <http://www.epa.gov/perftrac/members/Summary_LEEDs.htm>

(2007) “LEED Certification Program Leads to Potential Benefits”. <http://www.nuwireinvestor.com/articles/leed-program-leads-to-potential-profits-51367.aspx>

(2008) “LEED for Homes Rating System”. <http://www.usgbc.org/ShowFile.aspx?DocumentID=3638>

(2005) “LEED for New Construction and Major Renovation.” <http://www.usgbc.org/ShowFile.aspx?DocumentID=1095>

McMahon, J.E. “Chapter 9”. The First state of the Carbon Cycle Report http://www.climatescience.gov/Library/sap/sap2-2/final-report/sap2-2-final-chapter9.pdf

National Academy of Sciences. 2008. “What you need to know about Energy”.

Northbridge Environmental Management Consultants. 2003. “Analyzing the Cost of LEED”. < http://www.cleanair-coolplanet.org/for_communities/LEED_links/AnalyzingtheCostofLEED.pdf>

LEED, 34



http://www.climatescience.gov/Library/sap/sap2-2/final-report/sap2-2-final-chapter9.pdf

http://www.usgbc.org/ShowFile.aspx?DocumentID=1095



http://www.nuwireinvestor.com/articles/leed-program-leads-to-potential-profits-51367.aspx

http://www.nuwireinvestor.com/articles/leed-program-leads-to-potential-profits-51367.aspx

http://www.epa.gov/perftrac/members/Summary_LEEDs.htm

http://sbt.siemens.com/customerlounge/whatsnew/press.249.asp

http://www.ibe.colostate.edu/projects/theses/johnson_thesis.pdf

http://www.costar.com/partners/costar-green-study.pdf


Pise, M. N. 2006. “LEED Documentation Process: Implementation Barriers for School Projects”. <http://www.chple.arch.vt.edu/CHPLE%20Research%20files/ETD_Madhulika.pdf>

Turner, C. and Frankel, M. “Energy performance of LEED for new construction buildings”. New Buildings Institute Report (2008).


Dudley, Chris. Real Energy “How does renewable energy change the way we do things?”.(2008).http://mdsolar.blogspot.com/2008/01/eroie.html

Energy Efficiency Contractor. Residential Case Study. (2003)http://www.evnut.com/solar.htm

Energy Star. Saving Calculators. (2007).http://www.energystar.gov/index.cfm?c=furnaces.pr_furnace

EPA. System Analyst Reseach. (2007).http://www.epa.gov/nrmrl/std/sab/traci/

First Environment. “Life Cycle Assessment Case Study:BEES Software”.http://www.firstenvironment.com/html/lca_and_bees.html

Fthenakis .Vasilis M. and Hyung-Chul Kim. PV EH&S Research CenterBrookhaven National Laboratory. “Life Cycle Analysis of Photovoltaic Systems”.

Horst1, Scot W. and Wayne B. Trusty, MA2. “Integrating LCA Tools in LEED: First Steps”.

Ivanovich, Micheal. Engineering Innovation. (2007).

Lippiatt, Barbara. NIST. Office of Applied Economics. (2007)www.bfrl.nist.gov/oae/software/bees.html

Nebel, Barbara. White Paper – “Life Cycle Assessment And The Building And Construction industry”. (2006).

Scheuer , Chris W. and Gregory A. Keoleian. “Evaluation of LEED Using Life Cycle Assessment Methods”. (2002).

Solomon, Nancy B. AIA. Green Sources Magizine. McGraw Hill construction (2008) http://archrecord.construction.com/features/green/archives/0506edit-3.asp

LEED, 35

http://www.bfrl.nist.gov/oae/software/bees.html

http://www.firstenvironment.com/html/lca_and_bees.html

http://www.epa.gov/nrmrl/std/sab/traci/

http://www.evnut.com/solar.htm

http://mdsolar.blogspot.com/2008/01/eroie.html

http://www.chple.arch.vt.edu/CHPLE%20Research%20files/ETD_Madhulika.pdf

http://www.chple.arch.vt.edu/CHPLE%20Research%20files/ETD_Madhulika.pdf


Stone, Kenneth R. What EPA Means When it Says, "Life Cycle Assessment". (2007)

Sunder, S. Shyam, Barbara C. Lippiatt and Jennifer F. Helgeson “NIST Metrics and Tools for Tall and Green Buildings”. (2008).

The Free Dictionary. Definition of EROEI. (2008).http://encyclopedia.thefreedictionary.com/Energy+returned+on+energy+invested

Tolley, G.S. and S.L. Shaikh. The greening of buildings. “RFF Weekly Policy” Commentary. (2008).

U.S Department of Energy. Building Energy Software Tools. Directory. (2008)

U.S Department of Housing and Urban development BD&C LCA .White paper, “Final Report Assessing Their Applicability to the Home Building Industry Life Cycle Assessment Tools to Measure Environmental Impacts”.

Working Group B (LCA Methodology); Interim Report #1. “ Integrating LCA into LEED”. (November 2006).


Diamond, R., M. Optiz, T. Hicks, B. Von Neida, and S. Herrera, Evaluating the energy performance of first-generation LEED-certified commercial buildings. Proceedings of ACEEE Summer Study of Energy Efficiency in Buildings (2006).

Enermodal Engineering and National Renewable Energy Laboratory, Laboratories for the 21st Century: Energy Analysis. Department of Energy Report DOE/GO-102003-1694 (2003).

Mills, E., G. Bell, D. Sartor, A. Chan, D. Avery, M. Siminovitch, S. Greenberg, G. Marton, A. de Almeida, and L.E. Lock, Energy efficiency in California laboratory-type facilities. Lawrence Berkeley National Laboratory Report LBNL-39061 (1996).

Mills, E. and D. Sartor, Energy use and savings potential for laboratory fume hoods. Lawrence Berkeley National Laboratory Report LBNL-55400 (2006).

Sartor, D. and M.A. Piette, W. Tschudi, and S. Fok, Strategies for energy benchmarking in cleanrooms and laboratory-type facilities. Proceedings of ACEEE Summer Study on Energy Efficiency in Buildings (2000).

LEED, 36

http://encyclopedia.thefreedictionary.com/Energy+returned+on+energy+invested


Scheuer, C., G.A. Keoleian, and P. Reppe. Life cycle energy and environmental performance of a university building: Modeling challenges and design implications. Energy and Buildings 35, 1049 (2003).

Tanimoto, J., A. Hagishima, and H. Sagara, Validation of methodology for utility demand prediction considering actual variations in inhabitant behavior schedules. Journal of Building Performance Simulation 1, 31 (2008).

Tolley, G.S. and S.L. Shaikh. The greening of buildings. RFF Weekly Policy Commentary. April 14, 2008.

Turner, C/ and M. Frankel, Energy performance of LEED for new construction buildings. New Buildings Institute Report. Also sourced in personal communications (2008).

U.S. EPA Federal Energy Management Program, Laboratories for the 21st century: An introduction to Low-energy design (2000).

LEED, 37


TABLE 1. Laboratory instruments and their powers and loads during high and low usage conditions.

Devices Power Maximum

(Resting) (W)

Low Usage Load

(kWh/yr)

High Usage Load

(kWh/yr)General Instruments

Refrigerator (40) 350 350Freezer 1,000 320 320

Oven 1,400 525 525Balance 240 10 85

Stirrer 1,300 100 1,000Ultrasonic cleaner 150 40 85

Computers (4) 280 60 300Hood lighting 160 0 450

Glove box-Lighting 80 0 220Glove box-Freezers (2) 2,000 640 640

Glove box-Pumps (3) 900 250 3,150Total 2,295 7,125

Ultra-High Vacuum FacilityMechanical pump 300 250 1,050

Diffusion pump 9,000 5,700 20,000Turbo molecular pump 20,000 12,000 24,000

Chiller 2,600 0 1,350Heater (for baking) (6) 300 0 2,400

Effusion cell 600 75 290Sample manipulator 2,000 240 960

Gas injector 1,000 120 480Evaporation source bias 30 4 15

Evaporation filament 1,000 120 480Lighting (3) 180 20 85

Voltmeter 24 0 11Total 18,529 51,121

Analytical Chemistry FacilityHPLC-Temperature controller 960 0 850

HPLC-Pump 220 95 1,050HPLC-Chromatographer 180 77 155

HPLC-Degasser 35 0 30Mass spectrometer 16,000 3,850 13,800Bio-safety cabinet 1,600 1,300 1,300

Centrifuge 1,500 0 1,300Total 5,322 18,485

LEED, 38


TABLE 2. Comparisons of automatic sash controller (ASC) and variable air volume system (VAV) as two energy savings measures for a fume hood. All savings values are calculated with respect to operations parameters of sash height and fan power, (H, P) = (6in, 1.8 W/cfm), 24/7 and per annum.

Energy Savings Measures Reducing Sash Height (H)

Reducing Fan Power (P)

Both

Required Devices; Cost Automatic Sash Controller;

$1,500

Variable Air Volume

System; $1,000

ASC and VAV; $2,500

Operations Parameters (H, P) (0.25in, 1.8W/cfm)

(6in, 0.8W/cfm) (0.25in, 0.8W/cfm)

Energy Savings 5,765 kBtu 2,263 kBtu 5,860 kBtu

LEED Points Based on Energy Savings

1 0.4 1

Energy Cost Savings $1,034 $189 $1,042

Present Value of Life-Time Energy Cost Savings (Life, 15 years; Discount Rate, 5%)

$10,065 $1,839 $10,139

Net Benefits $8,565 $839 $7,639

LEED Points Based on Net Benefits

1 0.1 0.9

Fuel Savings 72 MBtu 0 72 MBtu

Carbon Emissions Due to Fuel 3,420 lb 0 3,420 lb

Carbon Cost Savings (CCX rate) $36 0 $36

Present Value of Life-Time Carbon Cost Savings (15 years; 5%)

$350 0 $350

Net Benefits Plus Carbon Cost Savings

$8,915 $839 $7,989

LEED Points Based on Net Benefits Plus Carbon Cost Savings

1 0.1 0.9

LEED, 39


Figure1. Correlation plots between design and actual energy usage intensities for non-

laboratory buildings (blue) and laboratory buildings (red). The dash lines indicate the

upper and lower limits of a variation of 190 kBtu/sf in laboratory energy intensity due to

variations in laboratory activities (see text). Raw data are from Diamond et al (2006) and

Turner and Frankel (2008).

LEED, 40


Figure 2. Building system EUI caused by laboratory plug and process EUI, based on a

laboratory model in Enermodal Engineering and NREL (2003).

Figure 3a. Dependences of fume hood energy usage on fan powers at constant sash

heights.

LEED, 41


Figure 3b. Dependences of fume hood energy usage on sash heights at constant fan

powers.

LEED, 42