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Krause Gateway Center, Des Moines, IA

LEED Sustainability Narrative – Schematic Design

July 28, 2015

LEED Overview

The current design is projected to achieve 56 points, thereby meeting the criteria for Silver under USGBC’s LEED NC v2009 rating system. With a concerted effort, the design team feels a Gold rating is feasible, and the minimum threshold is 60 points. There are still several credits listed as a ‘maybe’, and as the design progresses, they will be resolved. Please see the end of this document for a copy of the current scorecard for this project.

LEED Credit Narratives

SUSTAINABLE SITES (SS)

SS Prerequisite 1: Construction Activity Pollution Prevention

The Storm Water Pollution Prevention Plan (SWPPP) for this project will meet State of Iowa DNR standards, and it will be equal to or more stringent than the EPA standard.

SS Credit 1: Site Selection

The site meets the criteria of this credit and

Is not considered prime farmland Has been previously developed Is not identified as habitat for any species on federal or state threatened or endangered lists Is not within 100’ of wetland defined by US code of federal regulations 40 CFR, nor within

boundaries identified by state or local jurisdictions Was not formerly public parkland

SS Credit 2: Development Density and Community Connectivity

The project will meet the requirements of the credit through Option 2 and will earn the full 5 credits for compliance. This credit is eligible for a regional priority credit as well.

SS Credit 3: Brownfield Redevelopment

Not attempted – the site is not a designated brownfield.

SS Credit 4.1: Alternative Transportation—Public Transportation Access

The project site exceeds the minimum requirements for the credit. The credit states: Locate the project within 1/4-mile walking distance (measured from a main building entrance) of 1 or more stops for 2 or more public, campus, or private bus lines usable by building occupants. This is a Regional Priority (RP) credit. An additional point for Exemplary Performance (EP) is also likely. EP requires 4 bus lines with a minimum of 200 rides daily.

OPTION 2.

SS Credit 4.2: Alternative Transportation—Bicycle Storage and Changing Rooms

Bike rack and shower facilities will be provided on site. More information about how many stalls/showers needed to qualify will be forthcoming once full time equivalent employee counts are finalized. This is a Regional Priority credit.

SS Credit 4.3: Alternative Transportation—Low-Emitting and Fuel-Efficient Vehicles

Preliminary assumption that we will not pursue this credit due to limited priority spaces in the underground parking areas.

SS Credit 4.4: Alternative Transportation—Parking Capacity

This credit is not attempted due to the underground parking count. This credit should be reassessed in DD to see if it can be achievable. There are a number of options to achieve the credit, however, Option 1: Need to provide 5% of the preferred parking stalls as carpool stalls – was used to determine the initial feasibility of the credit.

SS Credit 5.1: Site Development—Protect or Restore Habitat

Case 2: Restore 50% of the site with 20% adaptive vegetation. Greenroof can be included if achieving SSc2.0. Our planting strategy will allow us to achieve this point especially with the greenroof in the project.

SS Credit 5.2: Site Development—Maximize Open Space

This credit is listed as a ‘maybe’ – both Troxel and SIF achieved this credit

SS Credit 6.1: Stormwater Design—Quantity Control

Maybe – water models used to determine compliance have not been completed yet, Regional Priority (RP) credit,

SS Credit 6.2: Stormwater Design—Quality Control

Maybe – water models used to determine compliance have not been completed yet.

SS Credit 7.1: Heat Island Effect—Nonroof

A combination of the following strategies for 50% will be used for site hardscape (including roads, sidewalks, courtyards and parking lots):

1. Provide shade from the existing tree canopy or within 5 years of landscape installation. Landscaping

2. Trees will be in place at the time of occupancy. 3. Provide shade from architectural devices or structures that have a solar reflectance index2 (SRI)

of at least 29. 4. Use hardscape materials with an SRI of at least 29. 5. Use an open-grid pavement system (at least 50% pervious).

SS Credit 7.2: Heat Island Effect—Roof

This credit will be pursued with a large green roof.

SS Credit 8: Light Pollution Reduction

The design team has been able to achieve this credit on past projects, and believe it will be feasible for this project. A close review of exterior lighting will be performed in DD phase.

WATER EFFICIENCY (WE)

WE Prerequisite 1: Water Use Reduction

We will surpass the 20% reduction requirement from WEp1 baseline standards. Low flow plumbing fixtures approved by owner will be provided to ensure compliance with this prerequisite.

WE Credit 1: Water Efficient Landscaping

This credit is currently listed as a maybe. The birch trees will need to irrigation over the parking garage and the green roof and any plantings underneath the canopy. The rest of the site should not need permanent irrigation.

The project will need to reduce potable water by 50% or more through the use of a combination of strategies that may include selection of plant species, density and microclimate factor, and irrigation efficiency

Recommendation: reevaluate the credit in DD phase.

WE Credit 2: Innovative Wastewater Technologies

Not attempted due to high cost of rainwater capture and treatment. This is a Regional Priority (RP) credit.

WE Credit 3: Water Use Reduction

Low flow plumbing fixtures, including two level manual flush water closets, pint flush urinals, and low flow aerators will be provided to achieve this credit – specifics of low flow fixtures will require review with owner. A preliminary comparison of the LEED baseline to project standards indicates the project is close to exceeding the savings threshold by 35%, which will earn 2 points.

ENERGY AND ATMOSPHERE (EA)

EA Prerequisite 1: Fundamental Commissioning of Building Energy Systems

An independent Commissioning Agent (Cx) will be supplied by the owner to fulfill the requirements of this prerequisite before the end of D phase. The requirements to meet this pre-requisite will be met within the scope of pursuing the Enhanced Commissioning Credit (EAc3).

EA Prerequisite 2: Minimum Energy Performance

The project will meet the prerequisite through option 1: whole building energy simulation. The minimum requirement for LEED is 10% better than ANSI/ASHRAE/IESNA 90.1 2007. See EAc1 for more information.

EA Prerequisite 3: Fundamental Refrigerant Management

No new CFC based refrigerants will be provided in the heating, ventilating, air conditioning and refrigeration systems to be installed for this project.

EA Credit 1: Optimize Energy Performance

The project will address the credit through option 1: whole building energy simulation. The results for the current design against ASHRAE 90.1 2007 are as follows:

The current design is estimated at approximately 20% above ASHRAE 90.1 2007 Appendix G Baseline, thereby achieving 5 points of 19 possible. Please refer to the SD Energy Analysis report provided by Atelier 10 as part of the SD package for more detailed information. The next phase will develop the energy model with more detailed design information.

EA Credit 2: On-site Renewable Energy

Not attempted – there is no additional room on the roof of the facility to support a PV array or solar hot water heaters, and there is not enough room to support a wind turbine.

EA Credit 3: Enhanced Commissioning

A Commissioning firm will be selected as the independent Commissioning Agent (Cx) supplied by the owner to fulfill the requirements of this credit. The Cx will be hired before the end of the DD phase.

EA Credit 4: Enhanced Refrigerant Management

We will pursue this credit. A refrigeration environmental impact score of less than 100 is required to achieve the credit.

EA Credit 5: Measurement and Verification

It is anticipated that the utility grade meters that will be provided within the scope of this project (electric, gas, domestic water) will support pursuit of this credit. The design team will work with the owner to develop a measurement and verification plan and determine which option to pursue.

EA Credit 6: Green Power

This credit is currently listed as a ‘maybe’, and can be used if needed. There are many local sources of low cost green power.

MATERIALS AND RESOURCES (MR)

MR Prerequisite 1: Storage and Collection of Recyclables

The design team will identify recycling on floor plan to meet the requirements of this prerequisite.

MR Credit 1.1: Building Reuse—Maintain Existing Walls, Floors and Roof

NOT ATTEMPTED.

MR Credit 1.2: Building Reuse—Maintain Interior Nonstructural Elements

NOT ATTEMPTED.

MR Credit 2: Construction Waste Management

The design build team has achieved in excess of the 95% recycled or salvaged waste on past projects. We will develop a plan to determine how the waste will be managed and reported to meet LEED guidelines. This is a Regional Priority (RP) credit and also carries the potential for an Exemplary Performance ID credit as well.

MR Credit 3: Materials Reuse

NOT ATTEMPTED

MR Credit 4: Recycled Content

We will exceed the recycled content threshold of 20% by weight using pre and postconsumer content in new materials. We will rely heavily on recycled content of concrete and steel to achieve the threshold. The team has experience achieving both credits on majority of projects.

MR Credit 5: Regional Materials

The project team proposes to exceed the 20% threshold for regional materials. Specifically, consider paving manufacturer plant location to help achieve the threshold.

MR Credit 6: Rapidly Renewable Materials

Not Attempted – it was decided we did not have enough information about the design to rely on achieving the credit at this point. This credit will be reassessed in DD phase.

MR Credit 7: Certified Wood

This credit will be pursued. A small amount of wood has been identified in the design – notably in the lobby area. Should the amount of wood used in the design increase, a reassessment of the credit will be necessary. Further refinement will occur in DD phase.

INDOOR ENVIRONMENTAL QUALITY (IEQ)

IEQ Prerequisite 1: Minimum Indoor Air Quality Performance

The minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda) will be met for this prerequisite.

IEQ Prerequisite 2: Environmental Tobacco Smoke (ETS) Control Required

This prerequisite will be achieved through the prohibition of smoking in the building and on-property within 25 feet of entries, outdoor air intakes and operable windows. Appropriate signage will be coordinated with the owner and provided.

IEQ Credit 1: Outdoor Air Delivery Monitoring

It is anticipated that this credit will be achieved. The credit requires monitoring of the outdoor air at every system, as well as the provision of CO2 sensors in all densely occupied spaces. Installation of CO2 sensors in densely occupied spaces will require review in DD phase.

IEQ Credit 2: Increased Ventilation

NOT ATTEMPTED - This credit requires outdoor airflow to be provided at 30% above the minimum rates required by ASHRAE 62.1-2007. This would require a significant increase in the OA airflow to the VAV reheat system for the office areas, which would in turn result in a significant increase in the size of the energy recovery unity. Consequently this credit will not be pursued.

IEQ Credit 3.1: Construction Indoor Air Quality Management Plan— During Construction

The team will draft an IAQ management plan that meets the requirements of the credit and will be distributed to all members of the team including subcontractors. SMACNA practices will be followed, with special care to order ductwork that is wrapped and that it is adequately protected during construction. Photos will be provided during construction to ensure that requirements are met.

IEQ Credit 3.2: Construction Indoor Air Quality Management Plan—Before Occupancy

This credit is listed as a ‘maybe’. The project is estimated to be substantially complete in winter months, which does not lend itself to Option 1: the prescriptive flushout methodology. If selected, this credit may be pursued through the use of Option 2: IAQ Testing, which requires testing of contaminant levels in space. If selected, the team will need to coordinate with the owner to achieve the credit. A rough estimate for the cost of the testing is $20,000, and there is a risk of nonperformance.

IEQ Credit 4.1: Low-Emitting Materials—Adhesives and Sealants

Using adhesives and sealants with low VOCs is an important component to providing a healthy building for occupants. We will track materials used in this category and provide product cut sheets for all materials that meet the green building performance criteria identified in the performance requirements, design requirements, or quality assurance paragraphs of each specification section.

IEQ Credit 4.2: Low-Emitting Materials—Paints and Coatings

The project will meet the requirements outlined in SCAQMD for paints and coatings similar to IEQc4.1 to achieve the credit. We will track materials used in this category and provide product cut sheets for all materials that meet the green building performance criteria identified in the performance requirements, design requirements, or quality assurance paragraphs of each specification section.

IEQ Credit 4.3: Low-Emitting Materials—Flooring Systems

The project will meet the requirements of the credit by adhering to the CRI standard for carpets, carpet padding and adhesives. We will track materials used in this category and provide product cut sheets for all materials that meet the green building performance criteria identified in the performance requirements, design requirements, or quality assurance paragraphs of each specification section.

IEQ Credit 4.4: Low-Emitting Materials—Composite Wood and Agrifiber Products

This is an all-or-nothing credit, and the team felt it was too early to say if feasible. We didn’t want to rely on the possibility of the point without having thought through the design of the interiors, but could move this credit into the maybe column if there is interest.

IEQ Credit 5: Indoor Chemical and Pollutant Source Control

This credit is listed as a maybe at this point. Strategies for achieving it include:

MERV 13 filters will be specified for ERUs, Air Handling units and fan coil units Ensure the entry mats fit in the vestibules.

IEQ Credit 6.1: Controllability of Systems—Lighting

Credit will be pursued. The threshold to achieve this credit is individual control for 90% of the occupants –which requires installation of task lighting.

IEQ Credit 6.2: Controllability of Systems—Thermal Comfort

Not Attempted.

IEQ Credit 7.1: Thermal Comfort—Design

The HVAC system will be designed to meet the conditions for thermal comfort described in ASHRAE Standard 55 – 2004.

IEQ Credit 7.2: Thermal Comfort—Verification

The design team will work with the owner to perform the required survey of building occupants.

IEQ Credit 8.1: Daylight and Views—Daylight

While the daylight and views in the building are excellent (clear glass to promote views, low glare potential, excellent shading), the project has a large floorplate that makes it challenging for natural light to penetrate deep enough into the core to achieve the point. After several discussions on the team and research provided by ARUP, we feel we will likely achieve the credit, but we are right on the threshold. As the building design continues to evolve, there are several components that could push us one way or the other. Factors affecting the credit include the location of internal walls and partitions, material choices on the site and in the interiors, FFE, among other things. As decisions are made to resolve these items, we check how they weigh on IEQ8.1 and 2.

IEQ Credit 8.2: Daylight and Views—Views

The project will exceed the 75% threshold for views.

INNOVATION IN DESIGN (ID)

Credit 1.1: Innovation in Design: Construction Waste Management (MRc2)

The project will implement a Construction Waste Management (CWM) plan to recycle and or salvage 95% or more of the C&D waste.

ID Credit 1.2: Pilot Credit (#57) Exterior Noise Control

http://www.usgbc.org/node/2606809?return=/credits/core-and-shell/v2009/pilot-credits

ID Credit 1.3: Innovation in Design: Sustainable Purchasing – Reduced Mercury in Lamps

Mercury is a toxic element that contributes to water pollution and poses human health risks. The project will adopt a plan to purchase lighting with less than 90 picograms of mercury per lumen-hour.

ID Credit 1.4: Innovation in Design: Alternative Transportation—Public Transportation Access (SSc4.1)

Exemplary performance requires 4 bus lines with a minimum of 200 rides daily are the qualifications – this site provides 10 lines and 386 stops per weekday and should easily qualify. See attached image for more information.

ID Credit 1.5: Innovation in Design: Commissioning the Building Envelope

Building Envelope commissioning shall incorporate building envelope review during design. Attention will be paid to Vapor Barrier, Air Barrier, Thermal Performance, building pressure, and air leakage during design and construction phases. The commissioning agent will develop construction checklists for use during construction to verify these systems are properly installed and operational.

ID Credit 2: LEED Accredited Professional

This credit will be met by a design team member with the appropriate credentials. Tate Walker of OPN Architects has the required credentials.

REGIONAL PRIORITY (RP)

Pursued

RP Credit 1.1: Regional Priority

SSc2 Development Density and Community Connectivity


SSc4.1 Alternative Transportation – Public Transportation Access


SS Credit 4.2: Alternative Transportation—Bicycle Storage and Changing Rooms

Potential


SS Credit 6.1: Stormwater Design – Quality Control

Not pursued

WE Credit 2: Innovative Wastewater Technologies

Environmental Design Consultants + Lighting Designers 45 East 20th Street 4th Floor New York NY 10003 T +1 (212) 254 4500 atelierten.com

Schematic Design Energy Analysis7558 Kum & Go Headquarters, June 29, 2015

IntroductionAtelier Ten conducted a whole building energy analysis for the proposed headquarters building of Kum & Go in Des Moines during the early Schematic Design (SD) phase. The purpose of this study is to characterize the building energy, assess project energy end-use components and evaluate the effectiveness of various envelope, lighting and HVAC alternates towards improving the energy performance. This study also benchmarks the Proposed Design against an ASHRAE 90.1-2007 LEED and 2010 Code Baselines.

Figure 1 summarizes the monthly internal and envelope gains and losses throughout the year. The chart emphasizes the significance of minimizing heat loss through window conduction during the winter months. Additionally, with large core spaces owing to a deep office floor plate, the internal gains attributed to lighthing and equipment translate to considerable cooling load even through the winter months. Given the site climate, incorporation of air-side or water-side economizer operation will help to considerably reduce cooling energy, especially in winter months.

FIGURE 2: SITE ENERGY CHARACTERIZATION FIGURE 4: ENVELOPE SENSITIVITY ANALYSISFIGURE 1: BUILDING MONTHLY LOAD COMPONENTS FIGURE 3: ENERGY SAVINGS WITH PROPOSED MEASURES

Proposed Energy Efficiency MeasuresThe bar to the left in Figure 3 represents the Proposed Design performance as presented in the energy use characterization section, and shows a site energy use intensity (EUI) of about 69 kBtu/ft2/yr.

The current proposed HVAC system with low temperature supply air, perimeter radiant heating, and high efficiency chillers and boilers offers about 18% savings in annual energy, and reduces the EUI to about 56 kBtu/ft2/yr.

The current design target to reduce the installed lighting power to 30% below ASHRAE 90.1-2010 levels results in savings in lighting and associated HVAC energy, and reduces the project EUI to 54 kBtu/ft2/yr.

Additional measures currently being considered include incorporating CO2 sensors in all office and meeting areas, and enthalpy wheel exhaust air energy recovery. Each of these ventilation strategies offer savings in space heating reducing the EUI to 52 kBtu/ft2/yr and 50 kBtu/ft2/yr respectively.

Energy Use CharacterizationThe energy model estimates energy uses for heating, cooling, pumps, fans, lighting, equipment and hot water. Figure 2 summarizes the annual energy consumption breakdown for these end-uses for the Proposed Design, which reflects the design intent for architectural systems with all other parameters at ASHRAE 90.1-2007 minimums.

Space heating forms the largest energy enduse (38%) followed by equipment (23%) and lighting energy (18%). Looking closely at the characterization graph, heat loss through window conduction and outside air heating are the major contributors to the space heating energy requirement. Accordingly, high performance glazing, demand controlled ventilation and exhaust air energy recovery should be incorporated in the design for increased energy efficiency.

Internal gains form a major component of the cooling energy. An efficient lighting design and high efficiency controls for both lighting and miscellaneous equipment will help reduce cooling as well as lighting and equipment energy.

Envelope SensitivityAtelier Ten created additional models to assess the effectiveness of various envelope improvements towards improving the energy performance of the building. These include varying levels of additional insulation on roof, and improved thermal performance of fenestration. Figure 4 summarizes the results of these envelope sensitivity tests.

The results suggest that HVAC energy savings of up to 25% can be achieved with improving the fenestration alone, owing to the reduction in conduction heat losses. An additional 5% savings in HVAC energy can be achieved with improved roof insluation. Reducing the glazing solar heat gain coefficient however, does not offer any benefit owing to substantial solar shading already provided by designed overhangs.

Based on these results, Atelier Ten recommends insulated glazing units to achieve fenestration assemblies with U-value lower than 0.25 Btu/hr-ft2-oF and roof insulation of R-35 hr-ft2-oF/Btu, beyond which further improvements only offer diminishing returns.

-5.00%

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0.4 0.35 0.3 0.25 0.2 0.15

ROOF INSULATION IMPROVEMENT IMPROVED FENESTRATION SHGC

IMPROVED FENESTRATION U-VALUE

ENVELOPE SENSITIVITY ON HVAC ENERGY7558 KUM & GO HEADQUARTERS

ROOF ASSEMBLY R-VALUE (hr-ft2-°F/BTU)

ANN

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HVA

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Y SA

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FENESTRATION ASSEMBLY U-VALUE (BTU/hr-ft2-°F)U-0.45 U-0.35 U-0.30 U-0.25 U-0.22 U-0.20

20 25 30 35 40 45SOLAR HEAT GAIN COEFFICIENT

ENERGY MODEL DISCLAIMER

The results from the energy model are accurate in terms of comparative evaluations of energy optimization measures assuming that all the other assumptions remain consistent. However, because energy model results rely on many assumptions about building occupancy patterns, they should not be construed as an absolute prediction of future building energy use.

2% 2% 3%1%

23%

3%3%

9%

WINDOW SOLAR LTG GAINS

EQP GAINS OCC GAINS

OA COOLING WINDOW CON

WALL CON ROOF CON

OA HEATING

LOAD COMPONENT

SITE ENERGY USE CHARACTERIZATION7558 KUM & GO HEADQUARTERS

8%

38%

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18%

COOLING HEATING GASPUMPS + FANS DHWEQUIPMENT LIGHTS

ENERGY END-USE

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WIN CON WALLS ROOFSWIN SOL LTG EQUIPOCC COOLING HEATING

BUILDING MONTHLY LOAD COMPONENTS7558 KUM & GO HEADQUARTERS

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PROPOSED VAV SYSTEM

TARGET LIGHTING POWER

CO2 SENSORSIN ALL SPACES

ENERGY RECOVERY

SPACE COOL SPACE HEAT HOT WATER VENT. FANS

PUMPS & AUX. AREA LIGHTS MISC. EQUIP.

ANNUAL SITE ENERGY CONSUMPTION7558 KUM & GO HEADQUARTERS

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18% 22% 24% 27%

Environmental Design Consultants + Lighting Designers 45 East 20th Street 4th Floor New York NY 10003 T +1 (212) 254 4500 atelierten.com

Summary of ResultsThe results in Figure 7 are presented for cumulative analysis, where each step also includes the efficiency measures associated with the previous step.

The considerably higher fenestration area in the Proposed Design relative to the 40% window to wall ratio in both LEED and Code Baselines translates to a significant energy cost penalty. The efficiencies associated with the currently proposed HVAC system however compensate for envelope losses and result in about 13% and 1% energy cost saving over the LEED and Code Baselines respectively.

The currently considered measures include a 30% reduction in installed Lighting Power, CO2 sensors in all spaces, and the exhaust air energy recovery, and further increase the savings by 8%, 1% and 2% respectively over the LEED Baseline.

Finally, potential measures that include Triple Pane Glazing, Chilled Beams, and a possible Hybrid GSHP plant can help increase the project energy cost savings by another 10%. Detailed model inputs and results from this analysis are presented in the Appendix at the end of this report.

BOILER

BASEBOARD HEATING

CHILLER COOLING TOWERCHILLED BEAMS

44°F

56°F

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55°F 44°F

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HEAT PUMP

BOILER

BASEBOARD HEATING


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FIGURE 6: SCHEMATICS OF EVALUATED HVAC SYSTEM ALTERNATES

BASEBOARD HEATING

CHILLER COOLING TOWER

44°F

56°F

55°F

110°F

140°F

BOILER

Mechanical System AlternatesAtelier Ten also evaluated various HVAC system alternatives, the schematics for which are presented in Figure 6 on the right.

A. All Air VAV System: This incorporates floor-by-floor air handlers with VAV zone terminal units. The chilled water and hot water is generated by onsite water cooled chiller and condensing boiler. This case forms the basis for proposed design against which all other cases are compared.

B. Zone Chilled Beams with Dedicated Outside Air System: This configuration decouples the primary ventialtion air conditioning from space cooling and heating requirement. Compared to all air systems, this alternative relies on water side economizer operation for winter time free cooling, and reduces reheat energy with independent zone controls. With a reduced fan system size designed only for primary air, this system will require considerably smaller mechanical space and ductwork requirements, and offer savings in fan energy.

C. Hybrid Plant with Ground Source Heat Pump: In this alternate, the previous configuration with chilled beams is modified to incorporate a 60-Ton water-to-water heat pump to generate a portion of the project chilled water requirement. The high efficiency system reduces cooling and heating energy at the expense of increased pumping.

D. Optimized Plant Configuration: This scenario builds upon the previous plant equipment to include two separate sets of chilled water loops, with GSHP supplying low temperature water for outside air cooling and dehumidification, and the chiller supplying high temperature water to chilled beams at significantly higher efficiency and free cooling potential. Additionally, an independent hot water loop supplied by the GSHP serves radiant floors in the lobby and perimeter baseboards to help balance the group well heat rejection and heat absorption.

Figure 7 summarizes the energy cost savings potential associated with different scenarios discussed earlier, along with potential envelope upgrages and HVAC system alternatives. All studied cases benchmarked against a LEED Baseline which reflects ASHRAE 90.1-2007, and the Iowa State Energy Code Baseline, which reflects ASHRAE 90.1-2010 minimally compliant parameters. The two Baseline Designs show an annual EUI of 64 and 56 kBtu/ft2/yr respectively.

FIGURE 7: ENERGY SAVINGS POTENTIAL - HVAC SYSTEM ALTERNATIVES

A

B

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Recommendations and Next StepsAtelier Ten recommends that the poject incorporate high performance argon-gas insulated double-glazed fenestration with low-E coatings and thermally broken frames. Additionally, the project lighting design should target at least 30% reduction in installed power compared to ASHRAE 90.1-2010 requirements. Finally, equipment selection and plug load control strategies should be explored to maximize efficiency.

With regards to HVAC systems, Atelier Ten strongly recommends a chilled beam system for the project. Although the annual energy cost savings alone might not justify the incremental first cost for the system, chilled beams will offer considerable reduction in ductwork and mechanical space requirements, and also offer better control and potential for future flexibility if floor layouts were to change. These parameters should be appropriately factored into any life cycle cost analysis. An optimized hybrid plant that incorporates a balanced ground source heat pump system and a rooftop PV array should be priced as add-alternates.

Atelier Ten will next update the energy analysis based on 50% Design Development documents.

LOBBY RADIANT FLOOR

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LEEDBASELINE

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PROPOSEDWINDOW AREA

PROPOSED VAVSYSTEM

TARGET LIGHTINGPOWER

CO2 SENSORSIN ALL SPACES

ENERGYRECOVERY

TRIPLE PANEGLAZING

CHILLED BEAMSWITH DOAS

HYBRID GSHPPLANT

NATURAL GAS ELECTRICITY

ANNUAL UTILITY COST SAVINGS - CUMULATIVE EFFECT OF VARIOUS STRATEGIES7558 KUM & GO HEADQUARTERS

UTIL

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/FT2 /

YR)

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-6% 13% 21% 22% 24% 29% 33% 34%

-20% 1% 10% 12% 13% 19% 24% 25%

Environmental Design Consultants + Lighting Designers 195 Church Street, Suite 10C New Haven CT 06510 T +1 (203) 777 1400 atelierten.com

Building Element Baseline Designs Proposed Design

Building Envelope Construction

Exterior Walls U: 0.064 Btu/hr-ft2-ºF (R-16) Same as Baseline Design

Roof Construction U: 0.048 Btu/hr-ft2-ºF (R-21) Same as Baseline Design

Slab on Grade Unheated Slab F-0.730 Same as Baseline Design

Floors U: 0.074 Btu/hr-ft2-ºF (R-13) Same as Baseline Design

Window-to-Wall Ratio 40% ~70% As Designed

Fenestration Assembly U: 0.45 Btu/hr-ft2-°F SHGC: 0.40 (SC–0.46) Same as Baseline Design

External Shading N/A Overhangs As Designed

Building Internal and Ventilation Loads

Space LEED Lighting (W/ft2)

Code Lighting (W/ft2)

Lighting (W/ft2)

Equipment (W/ft2)

Occupancy (ft2/person)

Auditorium 0.9 0.79

Assumed Same as LEED Baseline

1.0 10

BOH Spaces 1.5 0.95 1.0 1000

Cafeteria 0.9 1.30 1.0 15

Expo Space 1.7 1.45 1.0 25

Lobby 1.3 0.90 0.5 100

Offices 1.1 0.98 1.5 200

Building Occupancy, Lighting and Equipment Schedules

Hour Occupancy Lighting Equipment

From To WD SAT WD SAT WD SAT 12:00 AM 1:00 AM 0% 0% 5% 2% 5% 5% 1:00 AM 2:00 AM 0% 0% 5% 2% 5% 5% 2:00 AM 3:00 AM 0% 0% 5% 2% 5% 5% 3:00 AM 4:00 AM 0% 0% 5% 2% 5% 5% 4:00 AM 5:00 AM 0% 0% 5% 2% 5% 5% 5:00 AM 6:00 AM 0% 0% 5% 2% 5% 5% 6:00 AM 7:00 AM 10% 0% 30% 2% 30% 5% 7:00 AM 8:00 AM 70% 0% 80% 2% 80% 5% 8:00 AM 9:00 AM 90% 0% 90% 2% 90% 5% 9:00 AM 10:00 AM 90% 0% 90% 2% 90% 5% 10:00 AM 11:00 AM 90% 0% 90% 2% 90% 5% 11:00 AM 12:00 PM 50% 0% 90% 2% 90% 5% 12:00 PM 1:00 PM 50% 0% 90% 2% 90% 5% 1:00 PM 2:00 PM 90% 0% 90% 2% 90% 5% 2:00 PM 3:00 PM 90% 0% 90% 2% 90% 5% 3:00 PM 4:00 PM 90% 0% 90% 2% 90% 5% 4:00 PM 5:00 PM 70% 0% 80% 2% 90% 5% 5:00 PM 6:00 PM 30% 0% 50% 2% 50% 5% 6:00 PM 7:00 PM 10% 0% 30% 2% 30% 5% 7:00 PM 8:00 PM 10% 0% 30% 2% 30% 5% 8:00 PM 9:00 PM 10% 0% 10% 2% 5% 5% 9:00 PM 10:00 PM 10% 0% 10% 2% 5% 5% 10:00 PM 11:00 PM 0% 0% 5% 2% 5% 5% 11:00 PM 12:00 AM 0% 0% 5% 2% 5% 5%

Building Element Baseline Designs Proposed Design

Air Side System Parameters

HVAC System Type CHW VAV w/HW Reheat; One per Floor Same as Baseline Design

Cooling SAT/Reset 55ºF / 5ºF Reset 50ºF / 10ºF Reset

Heating SAT 90ºF Same as Baseline Design

Perimeter Heating n/a Perimeter Radiant

Ventilation Air Based on ASHRAE 62.1; 15,000 CFM Project Total Same as Baseline Design

Economizers OA Temperature; 70 ºF dry-bulb high limit Same as Baseline Design

Fan System Power 1.20 W/cfm, Variable Speed Control Same as Baseline Design

VAV Box Min Flow LEED: 0.4 cfm/ft2 Code: 0.3 Min Flow Ratio 0.3 Min Flow Ratio

Water Side System Parameters

Cooling Type

LEED: Two (2) water-cooled electric screw chillers, 5.5 COP Code: Two (2) water-cooled electric centrifugal, 6.1 COP

One water-cooled electric centrifugal chiller, 6.1 COP

CHW Temp 44ºF / 56ºF; Outdoor Air Reset Same as Baseline Design

CHW Pumps 22W/gpm; Const Primary, Var Secondary

22W/gpm; Variable Primary / Secondary

Heating Type Natural Gas Boilers; 80% Eff.

Condensing Boilers; 92% Eff.

HW Temp 180ºF / 130ºF; Outdoor Air Reset

140ºF / 110ºF; Reset Based on Load

HW Pump Power 19 W/gpm; One speed Primary

19 W/gpm; Variable speed pump

Heat Rejection Cooling Tower; Two-speed fans Same as Baseline Design

CW Pumps 19 W/gpm; One speed pump

19 W/gpm; Variable speed pump

Utility Rates

Electricity/Gas $0.065/kWh; $0.625/Therm Same as Baseline Design

Evaluated Energy Efficiency Measures

Reduced Lighting Power Installed lighting power 30% lower than ASHRAE 90.1-2010 levels

CO2 Sensors all Spaces Demand Controlled Ventilation in all office spaces

Energy Recovery Enthalpy Wheel, 75% Effectiveness in all Air Handlers

Triple Pane Glazing Fenestration U: 0.25 Btu/hr-ft2-°F; SHGC: 0.40

Chilled Beams with DOAS Zone terminal chilled beams with dedicated outside air system

Hybrid GSHP Plant 60-Ton ground source water to water heat pump

General modeling parameters

Analysis Tool: eQuest (DOE 2.2 Engine) v3.64

Weather File: DOE 2.2 TMY2 weather file for Des Moines, IA

ASHRAE Climate Zone: 5A

Energy Modeling Standard: ASHRAE 90.1 2007 Appendix G Performance Rating Method

Ventilation Standard: ASHRAE 62.1-2007

Building Area (as simulated with DOE 2.2): approx.150,000 gross ft²

Number of Floors: Four (4)

New Construction: 100% New Construction

Principal Heating Source: Chilled Water

Principal Cooling Source: Hot Water

Design Cases: Evaluated Cumulatively

Site Energy Intensity (kBTU/ft²/yr)

Annual Energy Costs ($/yr)

Energy Cost Savings over LEED Baseline (%)

Energy Cost Savings over Code Baseline (%)

LEED 2009 EAc1 Points

LEED Baseline 64 $112,887 - - -

Code Baseline 56 $99,143 - - -

Proposed Window Area 69 $119,210 -6% -20% -

Proposed VAV System 56 $98,063 13% 1% 1

Reduced Lighting Power 54 $89,307 21% 10% 5

CO2 Sensors all Spaces 52 $87,728 22% 12% 6

Energy Recovery 50 $85,800 24% 13% 7

Triple Pane Glazing 42 $80,045 29% 19% 9

Chilled Beams with DOAS 39 $75,169 33% 24% 11

Hybrid GSHP Plant 36 $74,539 34% 25% 12

GRAPHIC RENDERING OF THE ENERGY MODEL

Energy Model Input Parameters

EA: SJ | EM REVIEW: SHR | MEMO REVIEW: NK

General modeling parameters

Analysis Tool: eQuest (DOE 2.2 Engine) v3.64

Weather File: DOE 2.2 TMY2 weather file for Des Moines, IA

ASHRAE Climate Zone: 5A

Energy Modeling Standard: ASHRAE 90.1 2007 Appendix G Performance Rating Method

Ventilation Standard: ASHRAE 62.1-2007

Building Area (as simulated with DOE 2.2): approx.150,000 gross ft²

Number of Floors: Four (4)

New Construction: 100% New Construction

Principal Heating Source: Chilled Water

Principal Cooling Source: Hot Water

Design Cases: Evaluated Cumulatively

Site Energy Intensity (kBTU/ft²/yr)

Annual Energy Costs ($/yr)

Energy Cost Savings over LEED Baseline (%)

Energy Cost Savings over Code Baseline (%)

LEED 2009 EAc1 Points

LEED Baseline 64 $112,887 - - -

Code Baseline 56 $99,143 - - -

Proposed Window Area 69 $119,210 -6% -20% -

Proposed VAV System 56 $98,063 13% 1% 1

Reduced Lighting Power 54 $89,307 21% 10% 5

CO2 Sensors all Spaces 52 $87,728 22% 12% 6

Energy Recovery 50 $85,800 24% 13% 7

Triple Pane Glazing 42 $80,045 29% 19% 9

Chilled Beams with DOAS 39 $75,169 33% 24% 11

Hybrid GSHP Plant 36 $74,539 34% 25% 12

GENERAL MODELING PARAMETERS

SUMMARY OF ANALYSIS RESULTS

ISSUE 00

KUM&GO HEADQUARTERS, DES MOINES, IOWA RENZO PIANO

Kum&Go Headquarters

Des Moines, Iowa

Daylight and Solar Access Analysis

ISSUE_00

4thJune 2015


3

ISSUE 00


1.0. DAYLIGHT ANALYSIS

Methodology

Daylight analysis was carried out by the advanced lighting simulation program Radiance. Radiance is a lighting simulation program designed to examine advanced lighting conditions. The program uses a physically based light-backwards ray tracing method, which means that it actually simulates the behaviour of light itself, rather than its effect as is done by other light simulation methods such as Radiosity. For this reason it can handle much more in the way of geometrical and material behaviour. The building was modelled under 2 standard skies: CIE standard Overcast sky, representing the worse case

scenario for the region.; Sunny sky with sun for specific periods; Daylight performance was analysed based on daylight factor (DF), which describes the proportion of internal illuminance over external illuminance and expressed as a percentage.

Predicted daylight factors were measured over a 500mm x 500mm (1.64ft x 1.64ft) grid—one measurement point per grid point- and displayed in contour maps over the floor plates. The measurement grid was placed at working plane level at 720mm (2.36ft) from the floor level. In addition we have also tested the amount of cummulative sunhours reaching the floor plates in summer (when excessive solar radiation is undesired) as well as over the period of a year.

Benchmarks

Internationally accepted metrics for benchmarking best practice dayight factors (DF) are described below:

DF< 2%: Space looks dark. Considered underlit. Electrical lighting in the daytime is probably needed;

DF between 2% and 5%: Space looks at least partially lit. Considered to deliver a good balance of daylight with reduced risk of glare. Electrical lighting in the daytime might be required as you reach the centre of the floor plan;

DF > 5%: Space seems to be lit mostly by daylight. May offer some risk of glare and excessive heat gains (must be assessed separately to evaluate actual risks considering the caracteristics of each project). Electric light during daylight may not be required.

(ABOVE) Radiance 3D Model (Aerial view) (ABOVE) Radiance 3D Model (West Façade)

N

(ABOVE) Radiance 3D Model (South Façade)

For this study we have considered a benchmark of DF 2% as a minumum target for the building, following international best practice metrics. Where DF reaches above 5%, the risk of glare must be assessed by a specific study, especially for clear sky conditions when illuminance may reach excessive levels.

Model

Calculations used 3D models of the proposed development as issued by the architect as current on the 26th of May 2015. An adjacent existing dark brick building to the east of the proposed building was included in the model.

Building Materials

Internal walls: 80% reflectance; Internal floors: 50% reflectance; Internal Ceiling: 95% reflectance

Upper surface of overhangs: bright white (83%), Lower surface of overhangs: bright white (83%)

ISSUE 00

4


(ABOVE) Scenarios used for overcast sky simulations

1. DAYLIGHT ANALYSIS

SCENARIO 1

SCENARIO 2

SCENARIO 3

SCENARIO 4

SCENARIO 5

SCENARIO 6

Scenarios

A total of 6 (six) scenarios were modeled.

The rationale behind the scenarios is based on the possibility of intervention on the adjacent brick building, turning its façades into bright white surfaces. The other action that the design team might consider is providing the ground hardscape surface within the site boundary with light coloured finishes.

Scenarios were tested so that the effect of each surface (adjacent building façade and site ground hardscape) could be assessed individually.

The following page shows the results of each scenario.

ISSUE 00

5


1.1. DAYLIGHT ANALYSIS: OVERCAST SKY (SCENARIO 1)

Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 1

DF (%)

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6



Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 2

DF (%)

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Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 3

DF (%)

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Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 4

DF (%)

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Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 5

DF (%)

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10



Level 1.1

Level 2

Level 3

Level 4 Level 1

SCENARIO 6

DF (%)

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11


SCENARIO 3 SCENARIO 2 DF (%): Overcast Sky SCENARIO 4 SCENARIO 5 SCENARIO 6

Le

ve

l 1

L

ev

el

1.1

L

ev

el

2

Le

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l 3

L

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4

SCENARIO 1

ISSUE 00

12


100% 24% 60% 50% 69%

PER FLOOR

1.7. PERCENTAGE OF FLOOR AREA WITH DF > 2% (OVERCAST SKY)

SCENARIO’S TOTAL

SCENARIO 1

SCENARIO 2

SCENARIO 3

SCENARIO 4

SCENARIO 5

SCENARIO 6

100% 36% 67% 54% 72%

100% 38% 65% 55% 64%

100% 23% 62% 53% 66%

100% 35% 64% 55% 72%

100% 39% 66% 56% 70%

DF> 2% at working plane DF< 2% at working plane

ISSUE 00

13


SCENARIO’S TOTAL

1.7.1. PERCENTAGE OF FLOOR AREA WITH DF > 1% (OVERCAST SKY)

SCENARIO 1

SCENARIO 2

SCENARIO 3

SCENARIO 4

SCENARIO 5

SCENARIO 6

ISSUE 00

14


1.8. COMPARISONS CONSIDERING THE EFFECT OF BRIGHT SURFACES AT THE ADJACENT BUILDING

VS.

(ABOVE) Scenario 1, Level 2. Section of the East façade facing the adjacent brick building. It shows approximately 12m (39ft) good daylight penetration

12m (39ft) 13m (42ft)

(ABOVE) Scenario 4, Level 2. Section of the East façade facing the adjacent brick building. It shows a gain of approximately 1m (3.2ft) of good daylight penetration compared to Scenario 1 (small contribution)

(ABOVE) Scenario 1 (ABOVE) Scenario 4

(ABOVE) There is a 1% improvement over total good daylight penetration (DF>2%) when applying bright surfaces to the adjacent building (small contribution)

VS.

12.5m (41ft) 13.4m (44ft)




(ABOVE) There is aproximatelly 1.3% improvement over total good daylight penetration (DF>2%) when applying bright surfaces to the adjacent building (small contribution)

VS.


12.5m (41ft) 13.5m (44ft)



(ABOVE) There is less than 1% improvement over total good daylight penetration (DF>2%) when applying bright surfaces to the adjacent building (small contribution)

ISSUE 00

15


1.9. COMPARISONS CONSIDERING THE EFFECT OF BRIGHT FINISHES FOR THE SITE HARDCAPE

(ABOVE) Scenario 4

VS. VS.

(ABOVE) Scenario 1

VS.


VS.


(ABOVE) Level 1, Scenario 1 (ABOVE) Level 1, Scenario 2 (ABOVE) Level 1, Scenario 3

(ABOVE) Level 1.1, Scenario 1 (ABOVE) Level 1.1, Scenario 2 (ABOVE) Level 2, Scenario 3



(ABOVE) Level 1.1, Scenario 4 (ABOVE) Level 1.1, Scenario 5 (ABOVE) Level 2, Scenario


(LEFT) We have observed increments in the order of 3.8% and 5.5% as we increase the reflectance of the site’s hardscape. This is not a major increase in good daylight penetration, but it is also not negligible and indicates some improvement. Care must be taken to assess the risk of glare caused by high reflectance surfaces onto building occupants and pedestrians.

(LEFT) We have observed increments in the order of 4.2% and 5% as we increase the reflectance of the site’s hardscape. This is not a major increase in good daylight penetration, but it is also not negligible and indicates some improvement. Care must be taken to assess the risk of glare caused by high reflectance surfaces onto building occupants and pedestrians.

ISSUE 00

16


1.10. CLEAR SKY (JUNE @ 12.00h): EFFECT OF BRIGHT SURFACE AT THE ADJACENT BUILDING

Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 6

Level 1.1 Level 1 General Comments

The building was modelled under a CIE standard clear sky (with the sun). Daylight performance was analysed based on daylight factor (DF). This exercise evaluates the effectiveness of bright surfaces at the adjcent building on a clear sky scenario on a set of dates and times. This section presents the results for June at midday.

The diference between scenarios 3 and 6 is the color of the adjacent building façade, being scenario 3 the original brick building, and scenario 6 the intervention with bright surfaces.

Given the position of the Sun at this particular time (image below), reflections from the adjacent building towards the project’s eastern façade will be limited. A slight overal improvement can be noticed on scenario 6, particularly at higher storeys. In both scenarios the area below DF 2% is minimal (negligible), and the majority of the floor plate stays above DF 5% which is a typical benchmark for high performance in daylight.

The building’s core, located at the eastern side of the building will limit daylight penetration deeper into the floor plate.

N

ISSUE 00

17


1.10. CLEAR SKY (JUNE @ 12.00h): EFFECT OF BRIGHT SURFACE AT THE ADJACENT BUILDING (CONT.)

Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

N

N

Slight Improvement

Sc

en

ari

o 6

Level 2 Level 4 Level 3

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18


1.11. CLEAR SKY (JUNE @ 16.00h): EFFECT OF BRIGHT SURFACE AT THE ADJACENT BUILDING

Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 6


This exercise evaluates the effectiveness of bright surfaces at the adjcent building on a clear sky scenario on a set of dates and times. This section presents the results for June at 16.00h for a comparison between scenarios 3 and 6.

Given the position of the Sun at this particular time (image below), reflections from the adjacent building towards the project’s eastern façade will be more significant. This is expected to happen in June from approximatelly 15.00h until sunset. A significant improvement limited to the eastern perimetre zone can be noticed on scenario 6, particularly at higher storeys. An increase in DF that varies from approximately 30 to 60% is expected for scenario 6 at the perimetre east side of the building.

Good daylight penetration is limited by the building’s core located at the eastern side of the building, right next to the adjacent construction.

The benefits of sunlight penetration are therefore hindered by the core, limiting daylight penetration deeper into the floor plate.

N

ISSUE 00

19


Approx. 30% improvement

1.11. CLEAR SKY (JUNE @ 16.00h): EFFECT OF BRIGHT SURFACE AT THE ADJACENT BUILDING (CONT.)

Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

N

N

Sc

en

ari

o 6




ISSUE 00

20


1.12. CLEAR SKY (DECEMBER @ 10.00h): EFFECT OF BRIGHT SURFACE AT THE ADJACENT BUILDING

Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 6


This exercise evaluates the effectiveness of bright surfaces at the adjcent building on a clear sky scenario on a set of dates and times. This section presents the results for December at 10.00h for a comparison between scenarios 3 and 6.

Given the position of the Sun at this particular time (image below), reflections from the adjacent building towards the project’s eastern façade will be mostly difuse reflections since direct sun will be almost perpendicular to that surface. This indicates very limited changes between both scenarios.

A slight overal improvement can be noticed on scenario 6, particularly at higher storeys.

In both scenarios the area below DF 2% will be similar (approximately 10% of total floor area). Areas below DF 5% which is a typical benchmark for high performance in daylight are also similar (approximatelly 30%).

The building’s core, located at the eastern side of the building will limit daylight penetration deeper into the floor plate.

ISSUE 00

21


Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

N

N

Sc

en

ari

o 6



Slight Improvement

ISSUE 00

22



Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 6


This exercise evaluates the effectiveness of bright surfaces at the adjcent building on a clear sky scenario on a set of dates and times. This section presents the results for December at 14.00h for a comparison between scenarios 3 and 6.

Given the position of the Sun at this particular time (image below), reflections from the adjacent building towards the project’s eastern façade will be more significant. This is expected to happen in Decemberfrom approximatelly 13.00h until 15.00h. A significant improvement can be noticed on scenario 6, particularly at higher storeys. An increase in DF that varies from approximately 25 to 40% is expected for scenario 6 at the perimetre east side of the building.

Good daylight penetration is limited by the building’s core located at the eastern side of the building, right next to the adjacent construction.

The benefits of sunlight penetration are therefore hindered by the core, limiting daylight penetration deeper into the floor plate.

ISSUE 00

23


Sc

en

ari

o 3

50% +

2%

5%

N

N

N

N

N

N

Sc

en

ari

o 6







ISSUE 00

24


1.14. CLEAR SKY (JUNE @ 12.00h): EFFECT OF BRIGHT FINISHES AT THE SITE’S HARDCAPE

Sc

en

ari

o 1

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 3


This exercise evaluates the effectiveness of bright surfaces at the site’s hardscape on a clear sky scenario on a set of dates and times. This section presents the results for June at 12.00h for a comparison between scenarios 1 and 3. The diference between scenarios 1 and 3 is the color of the site’s hardscape, being scenario 1 the original a low reflectance finish (30%), and scenario 3 the intervention with high reflective surfaces (80%). Both scenarios contemplate the original low reflectance adjacent building.

Given the position of the Sun at this particular time (image below), reflections from the imediate ground will be significant. Combined to the high reflectance of the bottom of the overhangs (83%), scenario 3 results in a significant improvement over scenario 1. An increase in DF from approximately 25 to 60% is expected for at all four perimetre zones of the building. Deeper good daylight penetration is also demonstrated.

The majority of the floor plate stays above DF 5% which is a typical benchmark for high performance in daylight.

N



ISSUE 00

25


Sc

en

ari

o 1

50% +

2%

5%

N

N

N

N

N

N

Sc

en

ari

o 3


1.14. CLEAR SKY (JUNE @ 12.00h): EFFECT OF BRIGHT FINISHES AT THE SITE HARDCAPE (CONT.)

Approx. 30-40% Improvement at the perimetres.

Approx. 30% Improvement at the perimetres.

Approx. 20-25% Improvement at the perimetres.

Improvement at Underlit zones

Improvement at Underlit zones

ISSUE 00

26


1.15. CLEAR SKY (DECEMBER @ 10.00h): EFFECT OF BRIGHT FINISHES AT THE SITE’S HARDCAPE

Sc

en

ari

o 1

50% +

2%

5%

N

N

N

N

Sc

en

ari

o 3


This section presents the results for December at 10.00h for a comparison between scenarios 1 and 3. The diference between scenarios 1 and 3 is the color of the site’s hardscape, being scenario 1 the original a low reflectance finish (30%), and scenario 3 the intervention with high reflective surfaces (80%). Both scenarios contemplate the original low reflectance adjacent building.

Given the position of the Sun at this particular time (image below), reflections from the imediate ground will be significant. Combined to the high reflectance of the bottom of the overhangs (83%), scenario 3 results in a significant improvement over scenario 1. An increase in DF from approximately 25 to 60% is expected for at all four perimetre zones of the building. Deeper good daylight penetration is also demonstrated.

The majority of the floor plate stays above DF 5% which is a typical benchmark for high performance in daylight.

N



ISSUE 00

27


Sc

en

ari

o 1

50% +

2%

5%

N

N

N

N

N

N

Sc

en

ari

o 3


1.15. CLEAR SKY (DECEMBER @ 10.00h): EFFECT OF BRIGHT FINISHES AT THE SITE’S HARDCAPE (CONT.)

Approx. 25% Improvement at the perimetres.

Approx. 50% Improvement

Approx. 50% Improvement

ISSUE 00

28


2.0. SUMMER CUMMULATIVE SUNHOURS

Level 1.1

Level 2

Level 3

Level 4 Level 1

General Comments

This section presents the results from a summer cummulative sun hours study. The legend shows the percentage of sun hours onto the floorplate (at work plane level) over the total sunlight hours available for the period. For this study we have considered the period from 8am until 7pm.

Results for summer show a very low amount of direct sunlight reaching the interior of the building meaning that overhangs are capable of blocking most of direct sunlight thus reducing indicent solar radiation onto the glass.

Most perimetre zones are subject to approximatelly 10-12% of the available sunlight hours.

N N

N N N

ISSUE 00

29


2.1. ANNUAL CUMMULATIVE SUNHOURS

Level 1.1

Level 2

Level 3

Level 4 Level 1

General Comments

This section presents the results from na annual cummulative sun hours study. The legend shows the percentage of sun hours onto the floorplate (at work plane level) over the total sunlight hours available for the period. For this study we have considered the period from 8am until 7pm.

Annual results show a very low amount of direct sunlight reaching the interior of the building meaning that overhangs are capable of blocking most of direct sunlight thus reducing indicent solar radiation onto the glass.


N N

N N N

ISSUE 00

30


3.0. SUNCHARTS: LEVEL 1.1

This section presents suncharts for the location overlayed onto the floo plate (reference point located at the centre of each façade at floor height).

It shows direct sun access onto the vertical surfaces at each façade.

N

ISSUE 00

31


3.1. SUNCHARTS: LEVEL 2



N

ISSUE 00

32





N

ISSUE 00

33





N

ISSUE 00

34


4.0 CONCLUSIONS

EFFECT OF BRIGHT SURFACES AT THE ADJACENT BUILDING

Overcast skies

Marginal improvement have been observed when considering bright surfaces at the adjaceny building.

Good dayligt penetration (DF>2%) under overcast sky conditions is expected to improve in approximatelly 1% over the entire floor area, which can be considered as a negligibe impact.

Clear skies

Depending on the the position of the Sun (usually low angle in the afternoons) significant improvements can be noticed at the perimetre zones, particularly at higher storeys. However, good daylight penetration is limited by the building’s core located at the eastern side of the building, right next to the adjacent construction.

The benefits of sunlight penetration are usually hindered by the core, limiting daylight penetration deeper into the floor plate.

Conclusion

We conclude by stating that the benefit of providing the adjacent building with bright surfaces is limited to the eastern perimetre (mostly under clear sky conditions) and does not signifcantly affect overall daylight performance of the building.

Care must be taken to assess the risk of glare caused by high reflectance surfaces onto building occupants if the adjacent building receives bright surface finishes.

EFFECT OF BRIGHT SURFACES AT SITE’S HARDSCAPE

Overcast skies

We have observed some improvement when increasing the surrounding hardscape’s reflectance.

Good dayligt penetration (DF>2%) under overcast sky conditions is expected to improve up to 5.5% over the entire floor area. This is not a major increase but it is also not negligible and indicates some improvement.

Clear skies

Depending on the position of the Sun (usually at high angle) reflections from the imediate ground will be significant, thus improving overall daylight performance.

Combined with the high reflectance of the bottom of the overhangs (83%), bright surfaces at the ground result in a significant improvement in daylight penetration. An increase in DF from approximately 25 to 60% is expected for at all four perimetre zones of the building. Deeper good daylight penetration was also demonstrated.

Conclusion

We conclude that bright surfaces at the site’s hardscape is a better option for daylight improvement. This can be combined with high reflectance surfaces at the top and bottom of the overhangs to allow reflected daylight to be redirected deeper into the floor plate.

Care must always be taken to assess the risk of glare caused by high reflectance surfaces onto building occupants and pedestrians, especially if ground reflectance is raised to 80%.

SUNLIGHT AND DIRECT SOLAR RADIATION

Studies demonstrated that façades will be subject to a limited amount of direct sunlight hours.


Conclusion

The designed overhangs are capable of blocking most of direct sunlight thus reducing indicent solar radiation onto the glass.

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