CBEI Building 101 Case Study

BUILDING TESTBED & PHASED RETROFIT CASE STUDY

Building 101 at The Navy Yard in Philadelphia

Executive Summary The Philadelphia Industrial Development Corporation (PIDC) undertook a series of Energy Efficiency Measures (EEMs) in Building 101 between 2011 and 2013 at The Navy Yard in Philadelphia, PA. CBRE, the building manager, acted as the primary consultant to PIDC in making specific technology recommendations. The Consortium for Building Energy Innovation (CBEI) was also instrumental as a consultant advising CBRE and assisting in preparing RFPs. CBEI leveraged the building retrofit project for building science research, which included instrumenting the building, collecting building performance data, performing extensive modeling, and testing intelligent building operation.

The major EEM installed—and the primary focus of this report—was a new building automation system (BAS), which in turn affected the operation of the building’s HVAC and lighting systems.

While upgrading the BAS, mechanical issues were identified in the HVAC system, including installed but inoperable variable-frequency drives on the air handler fans, exhaust fans that were no longer required, and a host of inoperable valves. Experience suggests that these kinds of mechanical issues are likely to be found when upgrading dysfunctional BAS systems, particularly since some of the manual overrides in BAS systems are quick fixes to systemic problems.

The unexpected mechanical problems necessitated additional expenditures; however, the BAS yielded significant energy cost savings by allowing scheduled control of space conditioning (heating and cooling) and lighting, as well as vastly improving the efficiency of the ventilation system. Improved scheduling meant that the building would no longer be heated and cooled (while within low and high temperature limits, respectively), or lighted (aside from emergency lighting) on weekends and after business hours. Outside the main scope of CBEI’s work, a pilot LED lighting upgrade was installed in one tenant space; its energy impacts are examined in this report. The sum of these measures is expected to reduce annual energy use by 40%, with a simple payback of 2.8 years (or 3.2 years when LED upgrade costs are factored).

A condensing unit failure occurred at the time of the EEM performance evaluation. The unit, one of three aging units installed around the same time, was at the end of its useful life when it failed. The imminence of replacing the other two units prompted a rapid building-level HVAC asset assessment, in which three replacement alternatives were evaluated. Ultimately a direct-replacement condensing unit with new evaporator coil was chosen. The new unit upgraded the refrigerant circuit from R-22 to R-410a, improved operating efficiency, and yielded the best return on investment for the whole building moving forward.

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Contents 4

Introduction ➡

Building 101 at The Navy Yard

➡

Project Values

➡

Energy & Cost Savings Summary

8

Project Development

9

Owner Motivation

10

14

➡

Building Automation System

➡

LED Lighting

➡

Condensing Unit

Building Occupants & Indoor Environmental Quality ➡

Lighting

➡

Thermal

➡

Acoustic

Technological Research ➡

Testbed Instrumentation

➡

Informatics Research

➡

Modeling Research

➡

16

dvanced Building A Control Research

Energy Efficiency Measure Evaluation ➡

Energy Savings Evaluation •

Ventilation System HUs VFD Replacements: ºA Supply Fans

º Exhaust Fans • Cooling System

➡

25

•

Heating System

•

Exterior Lighting

•

Interior Lighting

ondensing Unit Failure C & Upgrade

Key Findings & Conclusions

4

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Introduction Building 101 at The Navy Yard Building 101 at The Navy Yard in Philadelphia, PA is the temporary headquarters of the U.S. Department of Energy’s Consortium for Building Energy Innovation (CBEI). The building is currently owned by the Philadelphia Industrial Development Corporation (PIDC) and managed by CBRE, both of which occupy tenant spaces in the building.

Initially built in 1911 to serve as a U.S. Marine Corps barracks, the building underwent a major renovation in 1999 to accommodate a single firm that owned and occupied the entire building as its headquarters.

A forced air heating and cooling system was added to the formerly hydronically heated1 barracks. Later, the firm left the building and sold it back to PIDC, which decided to divide Building 101 into a multitenant office building in response to market pressure for smaller tenant spaces, bringing it to its current state. PIDC’s building conversion required additional tenant fit-out, but did not include detailed study of the air distribution system within the building.

The building envelop is constructed of three-course brick punctuated by wood-framed double hung windows (screwed shut for HVAC purposes) and single-pane decorative fixed windows. Exterior

End Use

AHU Supply Fans Exhaust Fans Cooling

Pre-Retrofit Electrical Energy Consumption (KWh)

Pre-Retrofit Natural Gas Consumption (CCF)

walls are neither insulated on the inside, which PIDC views as a key design feature, nor on the outside, because this is not permissible for historic buildings.

Lighting is predominantly in the form of overhead T-5 fluorescent lamp fixtures. Heating, cooling, and ventilating of the building is delivered by three direct expansion split systems2 installed in 1999. Three air handling units (AHUs) supply a total of 27 variable air volume (VAV)3 boxes supplying conditioned air to 27 zones within the building.

Gross Building Floor Area is 75,156 ft2 with 65,214 ft2 of conditioned area currently found in the building, including a portion of the basement and three above-ground floors. For 2012, the weighted average occupied space was about 59,956 ft2 or 92%.

Annual Electrical Energy Savings (KWh)

Annual Natural Gas Savings (CCF)

Standardized Annual Savings (MMBTU)

Annual Cost Savings ($)

184,697

112,756

384

$16,575

13,884

9,880

34

$1,452

250,001

108,660

370

$15,973

958

$12,559

Heating*

22,000

9,303

Exterior Lighting

16,316

3,600

12

$529

Interior Lighting

266,603

56,422

192

$8,294

1,951†

$55,383†

Total

291,318

9,303

Table 1: Summary of anticipated energy and cost savings from the full suite of EEMs installed in Building 101 and discussed in this report. MMBTU is used as a standardizing unit so that modeled heating energy savings can be compared with the other EEMs’ electrical savings. * A complete analysis of the heating system’s actual energy impacts will take place following the 2013–14 heating season.

Current energy assessment is based on energy simulation modeling. † Numbers may not add up due to rounding.

Introduction

Project Values CBEI’s mission is to transform the energy efficiency market for small- and medium-sized commercial buildings, so these buildings are retrofitted and operated with low-cost, integrative technologies and innovative practices. Practitioners at CBEI approached Building 101’s retrofit as an opportunity to demonstrate the validity of applying integrative technology and innovative practices in a historical structure.

Shortly after CBEI was established in 2011, it set up its operational offices in Building 101.

A partnership with the PIDC ensued, made possible by PIDC’s leadership and vision for an energy efficient future for The Navy Yard. Both parties’ values were instrumental in driving the retrofit project; some values are shared by PIDC and CBEI, while others are unique to each party.

• Demonstrate successful implementation— proving energy and cost savings while being fiscally sound—of EEMs in practice (PIDC and CBEI) The PIDC is a non-profit city agency whose sole mission is to create economic development opportunities for Philadelphia.

Among other major endeavors, PIDC is managing the redevelopment of The Navy Yard in Philadelphia as an “energy campus.”

Their development strategy is based on controlled energy use growth, so that energy can be delivered reliably and affordably to all owners and lessees. The Navy Yard’s expansion will include much planned new construction, but will also leverage legacy structures, many of which are historic buildings, like Building 101, and which will need interventions to ensure optimal energy performance. Hence, PIDC views the experience gained in retrofitting Building 101 as a commodity that can be applied to future projects. PIDC is also seeking to apply these same experiences to the broader market

based on their larger mission of boosting economic development.

Ultimately, PIDC’s decision-making is driven by achieving the greatest return on property holdings; however, they are less profit-driven than private-sector counterparts, because decisions are counterbalanced by the economic development mission. As standard practice, PIDC operates their real estate holdings on an unsubsidized basis, paying for all upgrades through available capital flow. Capitalization may draw from a capital account provided that there is sufficient financial justification for the expenditure. Thus, all investments discussed in this report were vetted by PIDC and their advisors. PIDC’s decisions are further discussed in the Owner Motivation section of this report.

CBEI will utilize the demonstrated energy performance improvements, utility savings, and financial return information as examples to help drive market penetration of advanced energy retrofits (AERs).

•E nsure occupant comfort and health during and after EEM installations (PIDC and CBEI) Building occupant comfort and health often take second seat to the design of building programming and layout. This omission is generally inadvertent, caused by unclear understanding of factors that influence indoor environmental health and occupant comfort.

But, today’s buildings must be designed to better serve their inhabitants with their health and comfort set as a design imperative.

CBEI performance testbeds are evaluated for their occupant comfort and indoor environmental quality, along with their energy performance. CBEI’s evaluation is discussed in the Building Occupants and Indoor Environmental Quality section.

PIDC has a commercial interest in maintaining the comfort of its tenants and building

occupants and in ensuring that the process of executing retrofit measures in tenant spaces is as unobtrusive as possible. Demonstrated improvements in health, comfort, and productivity add value beyond simple energy cost savings, as documented by the Rocky Mountain Institute.4 This added value is typically glossed over, but it can help make the case for investing in advanced energy retrofits for PIDC and other developers.

CBEI’s mission is to transform the energy efficiency market for small- and medium-sized commercial buildings, so these buildings are retrofitted and operated with low-cost, integrative technologies & innovative practices.

•M ake a better business case for advanced energy retrofit investment (CBEI) Energy cost savings derived from EEMs is, for most property owners, the only consideration for investing in an EEM. These cost savings do make the case for the investment, but they belie the true depth of value offered by EEMs, which may include improved occupant comfort and health, higher rental rates, improved occupancy rates, and increased property valuation. And, as Rocky Mountain Institute explains, gauging value beyond energy cost saving can reduce investment risk and thus require a less significant discount rate or rate of return.5 The challenge with this proposition is that it has been very difficult

while air flow rate is varied to meet changing needs for heating and cooling.

1

Hydronic heating refers to the use of heated water as the transfer medium for space heating.

2

split system is a combination of an indoor air handling unit and an outdoor condensing unit.

A In direct expansion, the air passing over the indoor cooling coil is cooled by transferring its heat to the cold refrigerant.

Muldavin, S. Beyond the Tip of the Energy Iceberg: Why Retrofits Create More Value Than You Think. Rocky Mountain Institute. (2013) Retrieved from http://www.rmi.org/summer_2013_esj_ beyond_the_tip_of_the_energy_iceberg_main

3

In a variable air volume unit, the supply air temperature for heating and cooling remains the same,

5

4

Ibid.

5

6

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

to quantify and prove to the investment community. CBEI will leverage its experience with Building 101 to help make the case that well-planned EEMs provide increased value beyond energy cost savings and thus reduce investment risk.

• Demonstrate effectiveness of integrative design in achieving superior retrofit outcomes (CBEI) Buildings are more than a sum of their constituent parts; rather, they function as a complex system of interacting pieces.

Therefore, in order for a building to operate as designed, it must be designed as a whole system. Integrative design has the added advantage of finding efficiencies that only become apparent when the entire system is analyzed. A clear example is the retrofit of the Empire State Building,6 which was designed with a greater EEM investment in the building envelope than originally budgeted. The added envelope measures significantly reduced the design cooling load and chiller requirements, allowing for a less costly retrofit of the existing system, instead of expanding capacity with new, larger equipment. The smaller chiller system savings more than offset the additional EEM costs for the envelope and led to very favorable economics for the overall project.

RMI refers to this phenomenon as “tunneling through the cost barrier,” a principle that very likely applies to most commercial buildings contemplating a comprehensive7 retrofit.

Integrative design relies on sustained collaboration among the design team— designers, contractors and the building owner—as they work towards the project’s goals and align around a set of predetermined values. CBEI is acting as an integrative design liaison for PIDC as they take a staged approach to improving the energy performance of Building 101.

The experience gained from work with this building is being applied to improve the nascent Integrated Design Roadmaps guidebook series.

• Apply Progressive Building Science Research (CBEI) CBEI’s core mission is one built around market change. Part of that mission is satisfied by interacting directly with the market to push solutions to retrofit design challenges.

A separate, but equally important part is validating existing and developing new technical tools employed by the market.

Building 101 has acted as a research testbed for energy measurement, modeling, operation, and informatics, as discussed in the Technological Research section.

All of these varied values come together in Building 101 and, much like the integrative systems thinking that optimizes building energy performance, these joint convictions act in concert to demonstrate the true depth of value that can be derived from simple energy efficiency measures.

Energy & Cost Savings Summary The energy performance impacts of installed EEMs were evaluated by using EnergyPlus9 models using measured sensor data described in the Testbed Instrumentation section of this report. Weather-dependent end uses, such as AHU supply fan energy and building cooling and heating energy were assessed using regression models.10 These models rely on time-synchronized weather data collected from Weather Analytics for the Philadelphia Airport, located four miles south of Building 101 and normalized using Philadelphia Typical Meteorological Year (TMY3) data. Scheduledominated, weather-independent end uses, such as exterior/interior lighting and exhaust fans, are assessed directly using statistical analysis to compare energy usage profiles before and after the retrofits for different day types (workdays and weekends).

Item

Capital Investment

Building Automation System

$81,300

Interior Lighting Controls

$17,300

Exterior Lighting Controls

$2,700

Replace all AHU VFDs

$17,500

T, RH, CO2 sensors for VAV Zone Controls

$9,500

Air Distribution System Testing, Adjusting and Balancing (TAB)

$16,300

Software Light Switches

$11,760

Controls Retrofit Total

$156,360

LED Fixtures and Lamps*

$22,728

Total EEM Evaluated

$179,088

Table 2: Retrofit capital investment breakdown. * LED fixtures and lamps were supplied by the Sustainability Workshop and installed by CBRE in-house labor.

This price represents total costs for 56 four-foot clear lens, bi-pin bases with 2 LED lamp tubes and dimming.

6

arrington E. and Carmichael C. Project Case Study: Empire State Building. Rocky Mountain H Institute. (2009) Retrieved from http://www.rmi.org/Content/Files/ESBCaseStudy.pdf.

7

omprehensive retrofits, often referred to as deep building retrofits, are full-building retrofits C that address most building systems and allow for enhanced energy savings through synergistic interplays between building systems.

9

Energy Plus Energy Simulation Software. U.S. Department of Energy. Retrieved from http://apps1.

eere.energy.gov/buildings/energyplus.

10

R egression analysis helps one understand how the typical value of the dependent variable changes when any one of the independent variables is varied, while the other independent variables are held fixed. Most commonly, regression analysis estimates the conditional expectation of the dependent variable given the independent variables: that is, the average value of the dependent variable when the independent variables are fixed.

Introduction

All evaluations of energy savings were based on actual measured energy data standardized to weather conditions, with the exception of natural gas use for heating, which will be evaluated following the 2013–14 heating season. Results of selected periodic comparisons were then projected to the whole year to assess annualized savings. EEMs are discussed further in the Energy Efficiency Measure Evaluation section.

Buildings are more than a sum of their constituent parts; rather, they function as a complex system of interacting pieces. Therefore, in order for a building to operate as designed, it must be designed as a whole system.

Summary of EEMs installed through Summer 2013 1. Building Automation System (BAS) retrofit a. S upply fans with VFDs (Air Handling Units) b. Exhaust fans c. C ooling system improvements (economizer, demand control ventilation, supply air temperature reset and zone temperature setback) d. Heating system improvements e. Exterior lighting controls upgrade 2. I nterior lighting LED upgrade in single tenant space 3. Air conditioning failure and upgrade PIDC is a direct electricity distributor to the Navy Yard, purchasing electricity directly from the wholesale market. The electricity rate taken from January–April, 2012 utility bills is $0.147/ KWh. PGW’s natural gas rate for 2012–13 is $1.35/CCF for commercial buildings.

Baseline energy use data was available from sensors installed in 2011. Post-retrofit electricity savings were measured and results extrapolated to give annual saving estimates. No measured post-retrofit heating gas use data was available for this report, so model-predicted impacts were used instead.

Post-retrofit electricity savings are estimated to be 291,318 KWh (40%) annually, for a cost savings of approximately $42,800.

Modeled post-retrofit gas savings is 9,303 CCF (42%) annually, giving a cost saving of about $12,500. All told, energy cost savings are expected to amount to around $55,300 annually.

The BAS retrofit cost $156,360, including originally out-of-scope work described in the Owner Motivation section. The project has an expected simple payback of 2.8 years. When the additional cost for the pilot LED upgrade is included, the total project’s payback increases to 3.2 years.

7

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BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Project Development In 2011, Building 101 was designated a CBEI “performance testbed” to develop a detailed understanding of the building’s physics, detailed load profiles, controls operability and systems integration. Baseline performance data acquisition began in October 2011. Beginning in late 2012, a set of energy efficiency measures (EEMs) was installed and performance was measured and analyzed.

During this same time period, the building was used as a testbed for CBEI research in intelligent building operation, modeling, and informatics.

The work described in this report represents PIDC’s first stage of investment. The building automation system (BAS) upgrade was identified as an urgent need warranting immediate investment and drew from available revolving capital. PIDC plans to continue with staged retrofits based upon a yet-to-be drafted asset management plan and the needs identified in this report.

TIMELINE OF ACTIVITIES

Original BAS and

CBEI Established

HVAC Units Installed

Building Energy

CBRE LED

HVAC DX

Audit Completed

Lighting Installed

Unit Replaced

Building 101

Manufacturer

Building M&V

Building M&V

New BAS

Constructed

No Longer Supports

Instrumentation

Instrumentation

Installed

Original BAS

Installed

Installed

1911

1999

2008

2010

2011

2012

ENERGY CONSUMPTION OF MPC & BASELINE

2013

Project Development / Owner Motivation

Owner Motivation PIDC’s strategy for energy efficiency investments in its real estate holdings is based on two principals. First, investments should be made as a continuum over time, not as one large set of projects. Retrofits should be timed to align with changes in occupancy and necessary capital improvements based on an asset plan. Secondly, equipment replacements should be evaluated for life-cycle cost, which accounts for operating costs, not only first cost. All of the EEMs are described in more extensive detail in the Energy Efficiency Measure Evaluation section.

Building Automation System PIDC, the building owner, implemented a BAS upgrade in December of 2012. PIDC’s decision was guided by an energy audit conducted in 2011 and confirmed by building performance data collected by CBEI. Typically, a complete building energy asset assessment11 is recommended before endeavoring to implement EEMs. However, in this case, the poor condition of the existing BAS and the energy and cost saving potential of its replacement made it practical for the owner to invest immediately.

The original BAS was installed in 1999 and operated on a proprietary framework, which had ceased to be supported by the manufacturer by 2008. By the time an upgrade was being considered, very few controls were still handled by this antiquated system and all temperature controls were being adjusted manually. Building systems were no longer functioning on a schedule, meaning that heating, air conditioning, and lighting operated continuously, even during unoccupied periods.

CBRE, the building management firm, which acted as PIDC’s design consultant, recommended a BAS upgrade in order to reduce the escalating operating costs as well as to increase tenant satisfaction related to indoor air temperature and comfort issues. CBRE and CBEI drafted an RFP to do this work, allowing flexibility to accommodate building science research, as discussed in the Technological Research section. After identifying service providers and vendors in the region with the requisite service capabilities for the project,

CBEI distributed the RFP directly to these companies, rather than issuing an open bid.

The RFP garnered nine bids.

The replacement building automation system needed to avoid repeating some of the issues encountered with the original, outdated control system. The new system programming would be embedded across all controllers, creating redundancy and backup in case of central control failure or bypass. Further, an open (i.e. non-proprietary) system was chosen so that any service provider would be able to access and program the BAS easily.

Based upon these established operational requirements, the pool was narrowed to four finalists. The selected bid was the lowest cost and also included vendor-recommended “voluntary alternates,” all of which were implemented: • Installation of lighting controls (interior and exterior) • Replacement of all variable frequency drives • Replacement of variable air volume controls and sensors • Installation of gas meters • Total rebalance of air and water system

LED Lighting The Sustainability Institute provides a hands-on educational curriculum for high school students in Philadelphia. In 2012, the Sustainability Institute proposed to replace CBRE’s 320W T-5 fluorescent lighting fixtures with LED fixtures.

In exchange, CBRE and PIDC would allow the

program to use the office space as a hands-on classroom for the program’s students.

PIDC and CBRE’s decision to allow the program to use space hinged on whether the expected interference of having students present in the office space during the installation was acceptable. Ultimately, the convenience was seen as an acceptable tradeoff for the expected energy and cost savings, especially given that all material and service was being supplied by the Sustainability Institute.

Condensing Unit During the summer of 2013, a refrigerant leak reduced one of the three condensing unit’s (CU’s) cooling capacity by half. The sudden failure of CU2 during summer working conditions constituted an emergency situation and necessitated immediate equipment replacement. Temporary units were brought in as a stopgap measure, but the emergency situation allowed building management to supersede the normal public bidding process.

This emergency exemption is noted because it allowed PIDC a greater degree of flexibility in selecting a replacement system than would normally be allowed them as a public-serving entity. CBRE conducted a rapid HVAC asset assessment since the other two condenser units are also reaching the end of their useful service and proposed three replacement options.

PIDC chose to replace the failed unit with a more efficient unit using the same technology because, despite the modestly higher energy efficiencies of the other two options, their capital costs were higher and the returns on investment were modest.

A complete building energy asset assessment provides a timed sequence of recommended energy efficiency measures designed to yield optimal energy efficiency of the building as a system taking into consideration specifics of the building systems and economic conditions.

11

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BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Building Occupants & Indoor Environmental Quality Indoor environmental quality (IEQ) encompasses indoor air pollutants, as well as conditions tied to human comfort (e.g. lighting levels, noise levels, air movement, and temperature). CBEI assesses IEQ through sensor measurements and by surveying occupants themselves. These dual analytics also enable researchers to correlate measured conditions to actual occupant comfort, which is then applied to building simulation software. CBEI conducted an IEQ field study involving spot measurement (18 NEAT instrument cart locations12 and 23 occupant surveys) in three tenant spaces and two continuous measurements (May 16–June 14, 2012 and July 18–July 27, 2013) at a single location. Spot measurements occur at a short time window and give a single data point, whereas continuous measurements record measurements at regular intervals over a long time period, giving a set of continuous data points.

EEMs installed in the building to date B U Ihave LDING 101 not appreciably affected the IEQ, with one exception. Researchers were able to compare the visual impacts of the fluorescent lighting installed in most of the building against the LED lighting installed in one tenant space in 2012.

The remaining IEQ evaluation gives a concise baseline of existing conditions, which can be used to guide future EEM designs.

BUILDING 101 FLOOR PLAN (FIRST FLOOR)

NEAT Spot Measurement

NORTH

CBRE Office

24-HOUR CONTINUOUS MEASUREMENT

Lighting luminance was measured in Building 101 after the LED lighting was installed. In two of the three tenant spaces—including CBRE’s space with LED lighting—average measured lighting levels were below the recommended range. Unlike the effects of excess lighting,

12

T he NEAT instrument cart is a compact package for measuring all of the variables that determine an area’s IEQ and comes equipped with a data logger and a laptop. All of the technology in the NEAT cart is off-the-shelf and mounted on a foldable luggage carrier, making it cost-effective and easy to replicate.

The NEAT cart is placed in the position of the occupant’s chair for approximately fifteen minutes for each workstation sampled. Hand-held readings of light levels, radiant temperature, and air velocity are logged. Before leaving the room, two digital pictures are taken with a fisheye lens to capture brightness and contrast, and with a standard lens to record the workstation configuration, furniture, and primary work surfaces. While the physical measurements are recorded, the occupant is asked to complete a user satisfaction questionnaire related to that day’s specific environmental conditions as well as a questionnaire about conditions over the entire year.

NEAT Spot Meas

Lighting Regulation for lighting in tenant spaces call for luminance of 300-500 lux on work surfaces,13 but many older buildings were designed to deliver much higher levels and in many cases this lighting intensity was achieved entirely by overhead lighting. Such intensive overhead lighting contributes to occupant discomfort,14 16 reduced productivity,15 and health impacts.

24-HOUR

PIDC Office

FLOOR PLAN (

13

R ichman, E. Requirements for Lighting Levels. Pacific Northwest National Laboratory. Retrieved from http://www.wbdg.org/pdfs/usace_lightinglevels.pdf

14

hang, Y.; and Altan, H. (2011): A comparison of the occupant comfort in a conventional Z high-rise office block and a contemporary environmentally-concerned building: Building and Environment; 46 (2), pp. 535-545.

15

ishihara, N., Nishikawa, M., Haneda, M., & Tanabe, S. (2006). Productivity with Task and N ambient lighting system evaluated by fatigue and task performance. In ISIAQ (Ed.), Proceedings, Healthy Buildings 2006, Lisboa, Portugal (pp. 249-252). Lisboa, Portugal: ISIAQ.

16

akir, A. E. (1991). Light and Health: Influences of Lighting on Health and Well-being of Office Ç and Computer Workers. Berlin, Germany: Ergonomic Institut für Arbeits- und Sozialforschung

EEB Hub

CONTINUOUS M

Building Occupants & Indoor Environmental Quality

BUILDING 101 FLOOR PLAN (SECOND FLOOR)

NEAT Spot Measurement

EEB Hub Headquarters

NORTH 24-HOUR CONTINUOUS MEASUREMENT

the lower lighting luminance did not correlate to occupant dissatisfaction. A reasonable take-away from this study is that the LED lighting does not appear to impact occupant satisfaction, despite yielding a slightly lower luminance output than the fluorescent lighting that it replaced. The immense lighting energy savings possible with LED retrofits makes this an important finding.

Thermal The continuous measurement yielded some expected findings. The first set of measurements from 2012 was conducted before the BAS upgrade. Temperature and air quality measures were within acceptable ranges set

by ASHRAE and EPA, respectively. However, before the BAS upgrade, both heating and cooling continued throughout the night and on weekends. The continuous measurements in 2013, after the retrofit, illustrated the expected impacts of BAS temperature setbacks on nights and weekends.

However, post-retrofit spot measurements and user satisfaction surveys told a different story

than the continuous measurements. HVAC inefficiencies resulted in an 88% temperature dissatisfaction rate for surveyed ground floor tenants and 57% for surveyed 2nd floor tenants with spot measures within user spaces showing temperatures outside of the acceptable range.

Meanwhile, 60% of ground floor tenants and 25% of 2nd floor tenants complained of stuffiness. Researchers hypothesize that these stuffy conditions are related to poor layout of work spaces relative to diffuser locations, a likely result of the subdivision of Building 101 into separated tenant spaces without an equivalent redesign of the HVAC system. This particular inefficiency is now a top priority for PIDC in future EEM design.

Acoustic The post-retrofit analysis of noise levels revealed a direct correlation between measured noise levels and user satisfaction.

Nearly all noise level measurements were above the recommended range of 40 db, with users reporting 60% dissatisfaction with noise levels due to other people’s conversations and 45% dissatisfaction due to noise from

mechanical and office equipment. All tenant spaces are configured in open-plan layouts, which contribute significantly to the poor acoustic quality of the spaces. Another source of loud ambient noise is high velocity air blowing out of supply air diffusers installed during the 1999 installation.

LED lighting does not appear to impact occupant satisfaction, despite yielding a slightly lower luminance output than the fluorescent lighting that it replaced.

11

B U I L D I N G W E E K E N D D A I LY C O D I N G E N E R G

On average, AHU supply fans consumed 500 KWh per weekend day before the retrofit.

500 BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard Control Tests 400

300

200

M AY 1 6 , 2 0 1 2 – J U N E 1 4 , 2 0 1 2 C O N T I N U O U S M E A S U R E M E N T: T E M P E R AT U R E ( D AY )

100 90 0 25

30

35

40

45

50

55

60

65

70

75

80

85

90

84

T E M P E R AT U R E ( ° F )

12

High Temperature: 78.0 Low Temperature: 68.0

No Night-Setback Temperature Control AV E R A G E D D A I L Y O U T D O O R A I R T E M P E R AT U R E ( ° F )

No Night-Setback Temperature Control

78

72

66

60 0 AM

2 AM

4 AM

6 AM

8 AM

10 AM

12 PM

2 PM

4 PM

6 PM

8 PM

10 PM

0 AM

W E D N E S D AY, J U N E 1 3 , 2 0 1 2 ( T E S T E D M AY 1 6 , 2 0 1 2 0 1 : 2 1 P M T O J U N E 1 4 , 2 0 1 2 0 8 : 4 4 A M )

M AY 1 6 , 2 0 1 2 – J U N E 1 4 , 2 0 1 2 C O N T I N U O U S M E A S U R E M E N T: T E M P E R AT U R E ( W E E K ) 90

J U LY 1 8 , 2 0 1 3 – J U LY 2 7 , 2 0 1 3 C O N T I N U O U S M E A S U R E M E N T: T E M P E R AT U R E ( D AY )

90 84

T EU MRPEE R( °AT T E M P E R AT F )U R E ( ° F )

T O TA L A H U S U P P L Y F A N W E E K E N D D A I L Y E N E R

600

High Temperature: 78.0 Night-Setback Temperature Control

Night-Setback Temperature Control Temperature Control No Weekend Setback 84 78

Low Temperature: 68.0

High Temperature: 78.0 Low Temperature: 68.0

78 72

72 66

66 60 FRI 06.08 60 0 AM

SAT 06.09

2 AM

4 AM

SUN 06.10

6 AM

MON 06.11

TUE 06.12

WED 06.13

F O8 RAMP E R I O D :10F AM R I D AY 0 612 . 0PM 8 . 2 0 1 2 – F2RPM I D AY 0 6 . 145PM .2012

THU 06.14

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J U LY 1 8 , 2 0 1 3 – J U LY 2 7 , 2 0 1 3 C O N T I N U O U S M E A S U R E M E N T: T E M P E R AT U R E ( W E E K ) 90

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M AY 1 6 , 2 0 1 2 – J U N E 1 4 , 2 0 1 2 C O N T I N U O U S M E A S U R E M E N T: T E M P E R AT U R E ( W E E K ) 90

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13

14

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Technological Research Testbed Instrumentation Measurement and verification (M&V) is the most valuable tool for fully understanding how a building is operating today and how a retrofit changes its energy performance.

Without proper measurement, a building is a black box whose inner workings are a mystery. Measuring building performance is necessary in verifying return on investment.

For the market, validated performance is necessary to improve investor confidence and reduce risk. Often this change in performance is judged from changes in utility bills, giving an overall impression. Building 101, in contrast, was outfitted with an extraordinary number of sensors to deliver an extremely high-fidelity view of how the building functions. This instrumentation and the baseline of energy performance established before any measures were installed enables researchers to validate all of the impacts of EEMs on specific building systems and in different tenant spaces.

Instrumentation was installed at over 500 sensing points that capture over a thousand pieces of information about the conditions inside and outside of the building. Specifically, the building’s ongoing real-time instrumentation captures: • Major electricity and natural gas uses in the overall building • Heating and cooling capacity delivered by the HVAC equipment in order to understand the building loads and equipment efficiencies

Informatics Research It is essential to get building occupants on board with reducing energy use in a commercial building, as plug loads are one of the top building energy uses.

Using Building 101 as a testbed for such occupant engagement, CBEI filtered through building sensor data and laid out a sleek dashboard display for the building lobby with the goal of making an intuitive display that helps users understand how energy is being used in the building.

• Local weather conditions near the building

Modeling Research

• Ventilation flow rates, as well as the heating and cooling loads and indoor air quality (IAQ) issues associated with them

Existing modeling tools often perform only moderately well at predicting the energy performance of existing buildings as a whole, and they are worse at explaining performance as a measure of discrete elements such as HVAC, lighting, and outlet or plug loads. These tools often yield inaccurate predictions of actual energy savings from energy control measures targeted at discrete components.

• Overall air leakage rates for the building, as well as the air flows and leakage rates induced by mechanical systems and natural forces • IAQ parameters, including temperature, relative humidity, and CO2, as well as airborne contaminants and potential hazards entering the building, including, CO, airborne particulates, and total (non-methane) volatile organic compounds After the instrumentation was completed in 2011, performance data was collected to establish an energy and IAQ baseline. This baseline is now used to calibrate and verify detailed simulation models of the building systems utilizing Energy Plus, as well as to quantify the impact of improvements.

The data collected in Building 101 and other commercial buildings in the region is being used to calibrate models, validate model predictions, and develop new models to provide more accurate results. CBEI researchers have had initial success using a unique modeling approach, known as inverse modeling, to establish models of buildings that could tune a conventional model. In doing so, designers are able to confidently use the models

ENERGY CONSUMPTION OF MPC & BASELINE

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MPC

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ELECTRICITY ENERGY CONSUMPTION [kWh]

ooled Chiller Reclaim

Technological Research

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to investigate effects of retrofits on energy efficiency.17 In other words, researchers are better able to model how retrofitted buildings will perform by observing actual buildings under real-world conditions.

Another research effort has focused on identifying and analyzing sources of uncertainty to determine which particular unknown variables in an existing building may lead to inaccurate model predictions. Tested on Building 101, the effort included running 100 Monte Carlo simulations18 of 28 variables in the Building 101 EnergyPlus model that were identified as uncertain due to missing information and simplifications. The experiment yielded 13 simulation models with predicted energy use intensity (EUI) within 5% of measured EUI and one model with cooling and heating within 1% of measured EUI, a much greater accuracy than can be attained from traditional modeling methods.

17

Advanced Building Control Research Building control systems centralize control functions, such as HVAC and lighting, making it far easier to manage conditions within the building. At a supervisory level, the control systems provide set points to zone controllers and schedules for equipment operation; lights and heat may turn on at 7:00 am and turn off at 6:00 pm, for example. Advances in control algorithms and improved, less-expensive sensors are now making it possible to advance building controls so that they function based on real world conditions, and not simply on preset assumptions. These systems rely on a model predictive control (MPC) structure, which takes weather, occupancy, and other sensor information and uses it to predict the conditions that will occur later in the day. This processing allows a building control system to operate optimally when heating and cooling.

Braun, J. E. (2002). An Inverse Gray-Box Model for Transient Building Load Prediction. HVAC&R Research, 8(1), from http://www.tandfonline.com/doi abs/10.1080/10789669.2002.1039 1290#preview

18

Early results of testing in Building 101 have been very positive, showing a 33% reduction in energy consumption for cooling and a corresponding improvement in occupant comfort during a twenty-day test period. The energy savings resulted from improvements in the system’s dynamically set temperatures for the supply air from the air handling units and various building zones.

onte Carlo simulations rely on repeated random sampling to obtain numerical results; M typically one runs simulations many times over in order to obtain the distribution of an unknown probabilistic entity. Source: Wikipedia http://en.wikipedia.org/wiki/Monte_Carlo_method

15

16

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Energy Efficiency Measure Evaluation By 2011, much of the original BAS functionality had been bypassed by building operators to maintain overall system functionality to the detriment of overall system operational performance. As a result, CBRE needed to present PIDC with a set of unbudgeted mechanical system improvements (e.g. inoperable valves and variable frequency drives). This result was cited by CBRE’s representative as the most critical insight resulting from this retrofit process. The representative noted that this retrofit case was unique, since the owner had the in-house expertise of EEB Hub consultants and was more capable of understanding that the issues brought to light by the BAS upgrade were not caused by the BAS upgrade. A less informed building owner may have found it difficult to separate these ideas, possibly concluding that the new BAS installation itself was flawed.

D AY

Researchers determined that the AHU fan power control issue was caused by minimum VFD speeds set quite high (to 75% of full speed), with these controls being manually overridden during much of their operating history. Further examination revealed that the 4 to 20 milliamp signal from the BAS systems was not being correctly interpreted by the VFDs, indicating a lack of initial commissioning

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were completely nonfunctioning. This fault is easily seen when reviewing operational data 18 19 20 21 22 23 24 (Figure 1) that shows that the AHU fans were essentially running continuously 24/7, but this data was only available through the EEB Hub’s advanced data acquisition system and would not otherwise have been available to a building owner or operator.

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A forensic assessment of the existing control system revealed that the system was likely not properly commissioned at the time of the 1999 installation and therefore may have never performed properly. One finding was that the three AHU variable-frequency drives (VFDs)19

D A I LY S U P P LY FA N P O W E R U S E W I T H E X I S T I N G B A S C O N T R O L

kW

While the business case for the BAS G H T I N G H O U R L Y replacement E N E R G Y U S Ewas made partly on the premise of improving building tenant satisfaction, the new BAS has not yet fully delivered on this Pre-Retrofit: October &expectation.

November, 2012 Weekend Instead, the system evaluation capacity made possible by the BAS has Post-Retrofit: April & May, 2013 Weekend revealed that many of the occupant discomfort issues derive from subdividing parts of the building into smaller tenant spaces while the HVAC was not modified to accommodate these changes. Thus, additional analysis and investment will be necessary to resolve some of the tenant comfort issues.

D AT E

Figure 1: Daily supply fan power use with existing BAS control. The graph shows that fan power is fairly constant, whereas properly functioning VFD controllers would reduce energy use by modulating fan speeds.

Energy Efficiency Measure Evaluation

and an inability for the VFD to ever (throughout their entire operational lifetime) modulate fan motor speed as intended.

The assessment of existing conditions revealed that four attic exhaust fans had been installed in the building: • One provided no function and apparently never operated; • One provided bathroom exhaust for the building core; • One provided exhaust from a basement space that used to be an exercise room and now is an office; • And the last had been used with an old volatile ink-based large format printer that required direct exhaust and that was no longer in the building.

The latter two exhaust fans ran constantly despite serving no apparent function, and so were permanently shut down after the controls upgrade and before test, adjust, and balance (TAB) was conducted on the air and water systems.

The new BAS system was specified to measure and control temperature, humidity, and CO2 levels in each of the 27 HVAC zones. This control feature equipped the BAS to operate using demand control ventilation with static pressure reset and supply air temperature control. In addition, enthalpy-based economizing control20 was also added, but implementation was somewhat limited by the small physical size of the outside air intakes.

The exterior lighting is now controlled by photocells and the interior lighting remains largely schedule-based.

The interior lighting control was upgraded to a scheduling control with a software override system that lets tenants manually switch lights

19

on during off-hour times. The package allows for both flexible occupant work schedules and tight building schedules. Essentially an 8:00 am to 6:00 pm schedule can be maintained over the entire building while an individual can override the schedule for one lighting zone for one hour at the press of a button with newly installed controls. When the software override system was initially deployed, the new software override buttons failed to operate correctly if the lights were manually switched off with the original light switches. Consequently, the original manual switches were removed in July 2013 and the lights were fully set to BAS scheduled control with extended operating hours put in place. The new software override buttons are fully operable, allowing occupants to turn lights on during scheduled “unoccupied hours” (i.e. after 6:00 pm on weekdays and all day on weekends).

Energy Savings Evaluation Ventilation System AHUs VFD Replacements: Supply Fans Baseline condition: • AHUs ran continuously (24/7) despite supply fans being equipped with VFDs.

•U pgraded BAS turns the AHUs on and off based on the occupancy schedules: units are normally shut off after 6:00 pm during the weekdays and all day on weekends.

•A n “optimal start control” algorithm was programmed into the BAS to let the units start earlier in the morning to pre-condition the spaces.

Estimated annual energy savings from weekend days = 52,143 KWh. Estimated annual energy savings from weekdays= 60,613 KWh.

The combined estimated annual AHU energy savings from fan motor modulation & weekend scheduled shutdown = 112,756 KWh.

• Fan motor speed was not modulated to maintain a duct static pressure21 setpoint as the VAV box dampers operated.

• The VFDs were manually overridden during much of their operating history and did not perform as typical VAV systems.

Post-Retrofit condition: • New VFDs were installed on the AHU supply fans.

• Minimum VFD speed was set at 30% of full speed and controlled by a duct static pressure setpoint between 0.5 inch water gauge (in. wg) and 1.1 in. wg based on load conditions.

T he variable-frequency drive controller is a solid state power electronics conversion system that converts AC line input to AC inverter output and in the process can vary the frequency of the power output below the normal 60 hertz and thus slow motor speed by the ratio of the delivered frequency. Motors controlled by a VFD can consume less power than uncontrolled motors.

Typically, fan motors in AHUs are a significant power consumer and energy savings are realized by slowing them based on changing building conditions.

20

nthalpy-based economizing controls utilize “free cooling” from outdoor air when conditions fall E within a preprogrammed range of air temperature and relative humidity.

21

tatic pressure is a measure of the potential energy of a unit of air in the particular cross section S of a duct. Air pressure on the duct wall is considered static. Imagine a fan blowing into a completely closed duct: it will create only static pressure because there is no air flow through the duct.

17

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

A H U S U P P L Y F A N W E E K E N D E N E R G Y U S E C O M PA R I S O N

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On average, AHU supply fans consumed 500 KWh per weekend day before the retrofit.

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Figure 2: Weekend daily total AHU supply fan energy use is plotted against outdoor air temperature for the pre-retrofit (04/01/2012-12/09/2012) and post-retrofit periods (04/01/2013- 07/01/2013). On average, the supply fans in the three AHUs would use about 500 KWh on a typical weekend day before the retrofit and 0 KWh after the retrofit. Note that the outliers circled on the graph are caused by other control system tests conducted by EEB Hub researchers, and do not reflect “normal” operation.

A H U S U P P L Y F A N W E E K D AY E N E R G Y U S E C O M PA R I S O N

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W E E K D AY AV E R A G E D D A I L Y O U T D O O R A I R D R Y - B U L B T E M P E R AT U R E ( ° F ) 72

Figure 3: Baseline weekday daily fan energy is not tied to outdoor air temperature and associated building load, because the supply fans were not being properly controlled by the pre-retrofit VFDs. The calculated averaged daily consumption was about 509 KWh. The post-retrofit weekday fan energy use was modeled using a change-point linear 66 regression model and shows the expected relationship between fan energy and temperature.

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Energy Efficiency Measure Evaluation

P R E - A N D P O S T- R E T R O F I T E X H A U S T FA N E N E R G Y U S E

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38.3885

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Baseline condition: • No economizer (free-cooling) control,

Baseline condition: • T he gas-fired boiler was enabled or disabled basedDXon outside air temperature in order to Replacement Air-Cooled Chiller avoid simultaneously heating and cooling.

DX VERSUS CHILLER OPTIONS

35

Post-Retrofit (April 2013) 30

• Direct-expansion coils are staged to maintain the supply air temperature at 700,000 a fixed setpoint.

•W hen enabled, the existing boiler was cycled on and off to maintain the heating hot -13.8% water supply temperature at its setpoint.

Post-retrofit condition: 600,000 • Each of the 27 zones uses a combination temperature, humidity, and CO2 sensor for 500,000 space condition control.

• T he system typically provided excess cold air and led to occupant discomfort.

SITE ENERGY [kWh]

AV E R A G E E X H A U S T F A N E N E R G Y U S E [ k W h ]

Heating System

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• T he BAS controls the DX coils to maintain 300,000 supply air temperature setpoints, which are set based on the load conditions.

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5 0.0000 0 Weekday Average

Weekend Average

Figure 4: Exhaust fan savings for a typical week.

Exhaust Fans Baseline condition: • Three of four exhaust fans ran continuously (24/7).

Post-retrofit condition: • Exhaust fan operation was rescheduled in the new BAS so that only a single exhaust fan would operate.

• This fan is scheduled to operate from 5:00 am to 11:00 pm from Monday to Friday, consuming 75 KWh per week.22 • The remaining three exhaust fans serve no current purpose and do not operate.

Estimated annual energy savings for the exhaust fan system = 9,880 KWh.

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Cooling System

15 kWh / day * 5 days / week

-8.7%

•C ombining economizer operation, demand 0 control ventilation, supply air temperature Electricity control, and zone temperature setback provides optimal energy savings for this system while maintaining acceptable indoor air quality.

• T he post-retrofit building cooling system does not operate on weekends, because the AHUs are programmed to turn off as described in the AHUs VFD section. Therefore, the postretrofit weekend cooling energy use should be zero except for very hot days when building interior air temperature rises above the maximum setback setpoint of 80 degrees.

Estimated annual energy savings from the weekends = 76,710 KWh. Estimated annual energy savings from the weekdays = 31,950 KWh.

Estimated total annual cooling energy savings = 108,660 KWh. (43% reduction from the pre-retrofit cooling energy use of the building).

19

Post-retrofit condition: • T he boiler is available all year to enable reheating, which is used to increase air temperature in cases where the actual cooling needs were below the system’s minimum airflow requirements. It is important to note that reheat provides comfort, but constitutes an increase in energy use.

• T he new control scheme has the AHUs turn off on weekends, as described in the AHUs Natural Gas VFD section.

Heating gas energy savings were based on modeled predictions and are estimated to be 9,303 CCF annually. Following the 2013–14 heating season, these impacts will be reevaluated utilizing actual energy usage normalized to weather data, as was performed for the other systems in this report.

Air-Cooled Chiller Heat Reclaim

20

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

B U I L D I N G W E E K E N D D A I L Y C O O L I N G E N E R G Y U S E C O M PA R I S O N

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Poly: (Pre-Retrofit: 06.02.2012–12.09.2012) y = 0.7039x2 – 38.811x + 469.55 R2 – 0.8803

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Figure 5: Building cooling energy weekend daily total cooling energy use plotted against outdoor air temperature for both pre-retrofit (06/01/2012-12/09/2012) and postretrofit periods (04/01/2013- 08/17/2013). A second-order polynomial model where the y-axis is the weekend daily cooling energy use and x-axis is averaged daily outdoor air temperature was fit to the pre-retrofit condition. The model was applied to calculate how much energy the pre-retrofit building cooling system consumed in a typical year.

Note that the points of post-retrofit high energy use are caused by control system tests conducted for other CBEI research.

B U I L D I N G W E E K D AY D A I L Y C O O L I N G E N E R G Y U S E C O M PA R I S O N

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3,000

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y = 0.893x2 – 65.802x + 1,352.7 R2 – 0.8021

Poly (Pre-Retrofit: 06.01.2012–12.11.2012) Poly (Post-Retrofit: 04.01.2013–08.16.2013)

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Figure 6: Building cooling energy weekday use comparison. The second-order polynomial model is fit to the pre- and post-retrofit building weekday daily cooling energy uses over the same time period as in Figure 5. This model again calculates pre- and post-retrofit annual cooling energy use.

0 AM

Energy Efficiency Measure Evaluation

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H E AT I N G S Y S T E M N AT U R A L G A S W E E K E N D U S E C O M PA R I S O N

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Figure 7: Weekend Natural Gas Consumption

H E AT I N G S Y S T E M W E E K D AY D A I L Y U S E C O M PA R I S O N

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BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

Exterior Lighting

Interior Lighting

Baseline condition: • Exterior lighting was controlled by a simple on/off control tied to a time-of-day schedule.

Baseline condition: • The majority of the overhead interior lights are 277V, 40W, 2’-long, U-shaped T5 fluorescent lamps. Each existing fixture holds eight bulbs (320W per fixture).

• Variations in day length over the course of the year required the building operator to make periodic adjustments to the on and off times in the schedule.

• Lights are controlled with manual switches.

Post-retrofit condition: • In a small experiment, the first floor, south wing office space’s fluorescent lamps and fixtures are replaced with LED equivalents.

A full evaluation of lighting needs and potential whole-building lighting fixture retrofit measures will be addressed during the Integrated Process workshops scheduled for Spring and Summer 2014.

Post-retrofit condition: • Exterior lighting is controlled by a photo sensor, which turns the lights on when ambient light levels fall below 60 footcandles (646 lux).

Estimated annual energy savings = 3,600 KWh.

Projected total annual lighting energy savings = 56,422 KWh

• Interior lights, except for emergency lighting, are controlled by a new schedule set up in the upgraded BAS system.

(21% of annual lighting energy use)

• Lighting can be turned on after hours using wall-mounted “software switches.”

E X T E R I O R L I G H T I N G E N E R G Y U S E F O R P R E - A N D P O S T- R E T R O F I T C O N D I T I O N S

60 The building external lighting system consumed about 48 KWh in a winter day and 41 KWh per day in summer before the retrofit.

D A I LY E X T E R I O R L I G H T I N G E N E R G Y U S E ( K W h )

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Figure 9: Exterior lighting energy use for pre- and post-retrofit conditions. Exterior lighting use decreases as daylight hours are extended in the Spring season, approaching the summer solstice. Outliers that lie above the curve are caused by cloud cover, while those falling below the curve are unexplained. The analysis was performed for a six-month period and extrapolated to calculate estimated annual savings.

23

Energy Efficiency Measure Evaluation

Condensing Unit Failure & Upgrade

W E E K D AY W H O L E B U I L D I N G 2 7 7 V L I G H T I N G H O U R L Y E N E R G Y U S E

14,000 Baseline conditions: Pre-Retrofit: 06.01.2012–12.09.2012 •E quipment installed in 1999 (all units Post-Retrofit: 04.01.2013–08.17.2013 approaching end of useful life) 12,000

60

Pre-Retrofit: October & November, 2012 Weekdays Post-Retrofit: April & May, 2013 Weekdays 50

•R -22 refrigerant 3 Air Handlers with DX cooling coil and Hot water heating coil 10,000

•3 DX Condensing Units (one 40 Ton unit and two 60 Ton units)

40

D A I LY G A S U S E ( C F )

M E D I A N H O U R LY L I G H T I N G E N E R G Y U S E [ k W h ]

H E AT

8,000

•N atural gas fired hot water boiler

30

CU2’s failure prompted a rapid building-level 6,000 HVAC asset assessment so that CBRE could decide on the most sensible replacement option, given the 4,000 need to replace the other two units in the near future. Three system level options were identified:

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1. Directly replacing CU2 with new higherefficiency DX split 0system with the intent 30 same with 35 CU1 40 in the future to do the and CU3;

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2. R eplace all three CUs with an air cooled chiller; and

H O U R O F A D AY

Figure 10: Weekday lighting energy use hourly profile comparison between pre-retrofit (October and November, 2012) and post-retrofit (April and May, 2013) periods. Two important trends can be seen: 1) there is a post-retrofit decline in lighting energy use during unoccupied hours (~50%), and 2) the small LED retrofit demonstration appears to have reduced total lighting energy use during occupied hours from a peak of ~50 KWh to ~45 KWh. Part of this reduced energy use is likely confounded by changes in building occupancy.

WEE

3. Replace all three CUs with air cooled chillers with added heat recovery for use in reheat in the summer instead of using the gas boiler.

D A I L Y S U P P L Y FA W E E K E N D W H O L E B U I L D I N G 2 7 7 V L I G H T I N G H O U R LY E N E R G Y U S E 18

AHU1

60

AH

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kW

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M AY 1 6 , 2 0 1 2 –

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H O U R O F A D AY

Figure 11: Weekend lighting energy use hourly profile comparison between pre-retrofit (October and November, 2012) and post-retrofit (April and May, 2013) periods.

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Pre-Retrofit: October & November, 2012 Weekend

BUILDING TESTBED & PHASED RETROFIT CASE STUDY: Building 101 at the Navy Yard

P R E - A N D P O S T- R E T R O F I T ENERGY USE

M O N T H L Y C O O L I N G / H E AT I N G E N E R G Y

150,000

Cooling

Heating

Preliminary energy efficiency impact E X H Aresults U S T FA N for the three options were calculated by using BAS and CBEI’s energy modelOriginal for Building 101 with the 38.0442 HVAC 40 Units Installed monthly load profile (Figure 12).

CBEI Established 38.3885

Pre-Retro

(Nov. 20

Manufacturer

Constructed No Longer Supports Conceptual estimates for35installed costs Original BAS between options one and two were deemed to 30 installed cost of the be similar in that the lower single air-cooled chiller would be offset by the increased higher2008 capacity 1911 cost to run 1999 a new 2010 25 electrical service to the chiller. The heat recovery from the chiller would reduce natural 20 gas use compared to the boiler. However, 15.4814 even with heat recovery, the relatively high 15 cost of installing the extra pump, piping, heat exchanger, and controls to make this system work would not provide 10 sufficient payback to justify the cost. The conclusion of this effort was to replace CU2 with 5a “like-kind” energy efficient DX unit.

0.0000

AV E R A G E E X H A U S T F A N E N E R G Y U S E [ k W h ]

C O O L I N G / H E AT I N G E N E R G Y [ k W h ]

Building 101

120,000

90,000

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2011

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Figure 12: Building 101 load profile.

DX VERSUS CHILLER OPTIONS

The unit replacement took place 8/9/2013 Weekday Average Weekend Average through mid-day 8/12/2013. Considering the post retrofit test period was from 04/01/201308/17/2013, the impact in performance of this new direct expansion (DX) system (CU2 and matching evaporator coils) was considered negligible on the data presented, but will be evaluated after the 2014 cooling season.

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Air-Cooled Chiller

700,000

-13.8%

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500,000

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Figure 13: DX versus chiller options.23

23

ote that the DX Replacement electricity use is likely overestimated, as the manufacturer’s published data was limited to starting at 70F outside air temperature, whereas the air cooled chiller ratings went down to N 55F. Therefore, researchers determined that the electricity difference between the first and second options (6.2%) should be considered negligible and between the first and third options should be 2.5%.

6

7

Energy Efficiency Measure Evaluation / Key Findings & Conclusions

Key Findings & Conclusions PIDC, which owns Building 101, is particularly forward-looking in its desire to improve energy performance of The Navy Yard’s building stock, because it is tasked with delivering energy to all of The Navy Yard properties; controlled energy growth is central to its master planning. Despite the importance of energy savings, PIDC’s decisions to implement several EEMs—to replace the BAS and install LED lighting in one tenant space—and its equipment selection when replacing a failed cooling unit were predicated upon a reasonable payback period and not exclusively in order to save energy.

The BAS upgrade—the crux of PIDC’s efforts to date—was a clear choice, as the existing control system was no longer functioning and the building was operating as though it was always occupied, without proper lighting and temperature setbacks.

CBEI assisted PIDC and its building operator, CBRE, in acquiring a new BAS and analyzed the energy savings of the new system. CBEI estimates that the BAS replacement and programming will save nearly 40% of the annual energy used in Building 101, based on actual energy usage (except for heating energy, which was modeled). This significant energy savings will yield a simple payback of 2.7 years (or 3.1 years if LED lighting costs are included), despite accounting for the unbudgeted cost of replacing the three supply fan VFDs. Specifically, energy savings are owed to: 1) installation of functional VFDs to module AHU fan energy use; 2) elimination of unnecessary exhaust fans; 3) more efficient heating and cooling during occupied hours; 4) minimizing heating and cooling during unoccupied hours; 5) reducing exterior lighting by using photosensors; and 6) reducing interior lighting by tight occupancy scheduling and pilot LED lighting in one tenant space.

While the EEM retrofits were undertaken to help improve tenant comfort related to inconsistent temperature, this problem still persists. However, the BAS upgrade has been instrumental in fully diagnosing the limitations of the HVAC system that are causing these comfort issues. Further, the system analysis and especially the TAB that were conducted as part of the controls system retrofit identified a host of mechanical issues that would have otherwise remained unidentified. While this may be viewed as a positive, allowing for important preventative maintenance and improved

occupant comfort, the uncovered mechanical issues did constitute unplanned costs to the owner at the time of the BAS upgrade.

In comparing the LED lighting piloted in one tenant space with the fluorescent lighting in the rest of the building, occupants in both spaces were equally satisfied with their space lighting. The finding means that LEDs, which are both more energy efficient and longer lasting, are a comparable lighting option for building owners.

The heavily instrumented Building 101 at The Navy Yard in Philadelphia provided a unique opportunity to evaluate the effects of energy efficiency measures implemented in a phased manner between 2012 and 2013. Beyond validating energy impacts, though, the building has served as a test-bed to advance building science research. CBEI researchers have utilized Building 101’s data stream to conduct cutting-edge research to improve building modeling accuracy, make buildings operate more intelligently, and create a two-way dialogue about energy use with building occupants.

PIDC has already begun an integrative design approach to further improve Building 101’s energy performance. Measures will be implemented based on a targeted asset management plan that will be drafted as part of the design process. PIDC will be looking at measures that can address the existing occupant comfort challenges that arose from subdividing the building into separate tenant spaces without modifying the HVAC system.

Meanwhile, CBEI will continue to utilize building data for its research.

25

The heavily instrumented Building 101 at The Navy Yard in Philadelphia provided a unique opportunity to evaluate the effects of energy efficiency measures implemented in a phased manner between 2012 and 2013. Beyond validating energy impacts, though, the building has served as a testbed to advance building science research. CBEI researchers have utilized Building 101’s data stream to conduct cutting-edge research to improve building modeling accuracy, make buildings operate more intelligently, and create a two-way dialogue about energy use with building occupants.

Acknowledgements

This material is based upon work supported by the Consortium for Building Energy Innovation (CBEI), an energy innovation Hub sponsored by the U.S. Department of Energy under Award Number DE-EE0004261. The Philadelphia Industrial Development Corporation has played a significant role in providing CBEI with building stock to instrument and a willingness to implement energy efficiency measure (EEMs) that CBEI recommends for implementation and analysis. Ana Smith, CBRE Operations Manager for the Navy Yard, and Will Agate, Senior Vice President for Navy Yard Management & Development at PIDC, have been extremely helpful in providing access to the building, equipment, and building automation system (BAS).

Disclaimer

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe on privately owned rights.

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Confidentiality

This report is considered public information.

Purpose

The purpose of this report is to provide an interim report and analysis of the retrofit measures implemented in the building through Summer 2013. The report’s analysis provides a comprehensive evaluation of energy efficiency measure (EEM) effectiveness by reviewing: 1) Energy and cost savings; 2) Alignment with owner motivations and business constraints; and 3) Contribution to EEB research goals.

Consortium for Energy Innovation 4747 S. Broad St. Building 101, Suite 210 The Navy Yard Philadelphia, PA 19112 215 218 7590 info@eebhub.org http://cbei.psu.edu U.S. Department of Energy Award Number: DE-EE0004261