Case Study

601 Lexington Avenue

Iconic midtown tower modernizes by recycling heat

As a partner of the Empire Building Challenge, BXP will complete a decarbonization pilot project at 601 Lexington Avenue. The 1.52 million square foot, 59-story, multi-tenant premier workplace in midtown Manhattan was constructed in 1977 and features building systems typical among commercial high-rises of a similar vintage. The innovative measures planned for implementation demonstrate a scalable and replicable decarbonization opportunity within a difficult-to-decarbonize building type. 

As part of their demonstration project, BXP will install water-to-water heat pumps to transfer heat from the condenser water loop to secondary water systems. Recovered heat will then be used to offset perimeter heating loads. By deploying existing technology in a novel way, this project creates a thermal network which utilizes heat that would otherwise be rejected to the atmosphere from the building’s cooling system. BXP will reduce the building’s annual steam consumption by over 30% with this innovative thermal system. 

BXP is a fully integrated real estate investment trust and is the largest publicly traded developer, owner, and manager of premier workplaces in the U.S. with a portfolio spanning 54.5 million square feet.

601 Lexington
Progress

Construction drawings are complete, and the project is awarded to the selected General Contractor. Water source heat pump equipment procurement has also been released.

Steam Use Reduction

30%

Heat recovery retrofit at 601 Lexington Ave will reduce annual steam consumption by over 30%. The project uses an existing technology in an innovative way to create a thermal network in the building, using heat that would otherwise be wasted.

Lessons Learned

Reducing demand and dependence on fossil fuel driven heating systems is an enablement step for building decarbonization.

Testimonial

“At BXP, we are committed to carbon-neutral operations and the advancement of built environment climate action. Climate action is collective action and alongside our partners at Norges Bank Investment Management, we are thrilled to pursue this decarbonization initiative at 601 Lexington Avenue.”

Ben Myers
Vice President, Sustainability
Boston Properties, Inc. (BXP)

Lessons Learned

The project is highly replicable elsewhere within the BXP portfolio and provides a bridge to carbon neutral planning.

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
  • New heat source potential
  • Efficiency improvements
Asset Conditions
  • Carbon emissions limits
  • Owner sustainability goals
Market Conditions
  • Technology improves
  • Policy changes
  • Utility prices change
  • Fuels phase out

BXP is committed to carbon-neutrality by 2025 for its actively managed occupied office buildings. Starting in 2010, BXP adopted a phased approach with a long-term goal of achieving low site energy use and reducing GHG emissions at 601 Lexington Ave. Compared to a 2010 baseline, BXP has reduced the building’s GHG Emissions by 47% and site EUI by 33%. The notable reduction in energy use was achieved through a series of targeted energy efficiency measures, including a building automation system upgrade, installation of Variable Speed Drives on all major HVAC equipment pumps and fans, lighting upgrades, modernization of the central chiller plant (replacing steam chillers with high efficiency variable speed electric chillers), and optimization of operational controls.   

To accelerate decarbonization efforts, the next phase of retrofit projects should be geared to reduce district steam consumption within the building. This initiative aligns with BXP’s decarbonization strategy and energy efficiency objectives and positions the building on a path towards full compliance with Local Law 97.  

The heat recovery project focuses on minimizing the dependence on district steam, a fossil-fuel sourced commodity. This project demonstrates a replicable decarbonization solution in existing commercial high-rise buildings and joins a list of energy conservation measures already deployed at the property. 

To  compare the energy and carbon reduction impact of the measure on a business-as-usual scenario, a comprehensive energy analysis was performed to establish a baseline operation and compare alternatives. The effort included review of existing HVAC systems, electrical infrastructure, space constraints, submetering of heating and cooling loads, potential for energy recovery to offset heat loads, and evaluation of energy use and costs.

The detailed energy analysis indicated a considerable reduction in energy and GHG emissions compared to baseline energy use and significant utility savings per year.

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Existing Conditions

This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.

Click through the measures under “Building After” to understand the components of the building’s energy transition.

Sequence of Measures

2024

2034

Building System Affected

  • heating
  • cooling
  • ventilation
601 Lexington Building Before
601 Lexington Building After
Install WSHP to reclaim heat for re-use in the building’s perimeter heating systems. An automated cooling tower bypass valve will retain heat in the building, maximizing heat available for recovery during the heating season.
Install hydronic coils in select AHUs to supply low temperature hot water for preheating ventilation air, keep steam coils as back-up
Install air source heat pumps. These will reclaim heat from the atmosphere, to produce hot water for the remaining heating loads.

The project at 601 Lexington Avenue will deploy existing technology in a novel way, creating a thermal network that recovers and utilizes heat which is otherwise rejected by the cooling towers. 

Through NYSERDA’s Empire Building Challenge, BXP will install water source heat pumps (WSHPs) that will capture waste heat from the condenser water loop. The recovered heat will be reused into the building’s perimeter heating.

Currently, the building condenser water system carries heat from base building and tenant cooling systems to the cooling towers, where it is rejected evaporatively to the atmosphere. In office buildings, this heat is often constant and available for recovery year-round. In the proposed measure, WSHPs will be installed. They will replace the function of the cooling towers during the heating season and will reclaim heat from the condenser water loop for beneficial use. An automated bypass valve will divert condenser water from the cooling towers, retaining as much heat in the building as possible for recovery by the WSHPs. The heat recovered will be reused in the building’s heating systems and will significantly offset reliance on fossil fuel-based steam. These measures will reduce annual steam consumption by an estimated 30%.

These measures partially electrify building heat sources while recovering waste heat for beneficial re-use. This results in reduced energy consumption and enhanced demand management. These measures are replicable for existing buildings, designed to be both space-efficient and cost-effective.

In addition to the WSHPs, air source heat pumps (ASHPs) may be installed in the future to produce low-temperature hot water to cover some of the remaining heating loads. The project team plans to continue investigating ASHP infrastructure within the physical space constraints of this occupied building to minimize reliance on steam heating.

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

$3.65M

Capital costs of decarbonization.

Avoided Risks

Business-as-Usual Costs

$262k / YR

Energy cost savings: 287k / YR.

Repairs & maintenance savings: 25k / YR. 

Avoided Risks

Business-as-Usual Risks

$120k / YR

LL97 avoidance from 2030-2034.

No fines in 2035+ assuming electric grid coefficient aligns with CLCPA goals.

Added Value

Decarbonization Value

$1.1M

Incentives.

Pursuing ConEd Rebates through the Clean Heat Rebate Program.

Net Present Value

$525k

Net difference between the present value of cash inflows and outflows over a period of time.

A simple payback measure as a standalone analysis does not accurately represent the benefit of decarbonization over time. A long-term outlook for decarbonization investments that accounts for utility cost escalations, building performance standard compliance fine avoidance, procurement costs to meet voluntary carbon neutral operations commitment over the life-cycle of the project, and other risks associated with taking the business-as-usual approach are critical while creating a business case for decarbonization.

The financial analysis for the project included a relative comparison to business-as-usual costs under various scenarios as described below:

  • Scenario 1 represented the financial impact of paying Local Law 97 penalties;
  • Scenario 2 represented a proactive procurement of carbon credits to minimally comply with Local Law 97;
  • Scenario 3 represented RECs and Carbon Credit procurement costs to achieve the goal of Carbon Neutral Operations by 2025.

The proposed project has a positive NPV when compared to a business-as-usual scenario and is a critical first step in the building’s long-term decarbonization plan as it significantly reduces the dependence on district steam for building heating loads. This is an enablement step for future decarbonization phases in 2034 and beyond. Additionally, the project is highly replicable elsewhere within the BXP portfolio and provides a bridge to carbon neutral planning.

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

To advance the building’s broad decarbonization objectives, and through the reduce, recycle, electrify approach, the team studied energy and carbon emission reduction pathways for 601 Lexington Avenue through a robust, collaborative process with multiple stakeholders. 

The decarbonization projects require a phase-in plan and a multi-step approach, which includes technical analysis, detailed design, procurement, and implementation. The preliminary technical analysis for the decarbonization roadmap was performed in Q4 of 2022 as part of the Empire Building Challenge application. The first phase of the decarbonization roadmap is the Condenser Water Heat Recovery project, which received NYSERDA funding through the Empire Building Challenge. The full design (DD and CD) of this project was completed in 2023 and construction is expected to be complete in 2025.  

On-site decarbonization efforts may be furthered in a subsequent second phase implemented in 2034 with electrification of heating and DHW through air source heat pumps. It is anticipated that the heat pump technology and pricing will continue to improve; because of that, the energy and GHG reductions reflected in the carbon neutrality roadmap below are conservative estimates. As an interim phase, starting in 2025, the building will achieve Carbon Neutral Operations for Scope 1 and Scope 2 emissions by offsetting them through a combination of renewable energy and carbon credits procurements.

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Case Study

The Towers

Oldest US multifamily co-op transforms wastewater into clean energy

In Bronx, NY, the Amalgamated Housing Cooperative (AHC) embarked on a pioneering low carbon retrofit project at ‘The Towers,’ two 20-story buildings containing 316 affordable apartments across 425,000 square feet. Established in 1927, AHC is the oldest limited equity multifamily co-operative in the country. 

The retrofit focuses on upgrading the heating and cooling infrastructure to enable simultaneous operation, diverging from the existing seasonal limitation. By introducing cutting-edge solutions including wastewater heat recovery and geothermal systems, AHC aims to harness energy from domestic water sources, thereby phasing out its reliance on cooling towers and decreasing fossil fuel consumption. This initiative not only promises enhanced thermal comfort and sustained affordability for its residents but also sets a benchmark for energy efficiency and climate resilience. The project’s success could potentially revolutionize energy management across similar multifamily complexes in New York State, demonstrating a scalable model for other buildings with similar heating and cooling system configurations– a total market estimated at 200 million square feet. 

AHC’s commitment to its low-to-moderate income community underscores this ambitious venture, reinforcing its legacy and leadership in sustainable development.

The Towers buildings
Emissions Reductions

93%

carbon emissions reduction on an all-electric site by 2035.

Lessons Learned

This project will make clean energy from dirty water by recapturing heat from sinks, showers, and toilets.

Lessons Learned

The project’s complete building re-piping decrease the future loaded needed for the planned geothermal heat pump system improving performance and comfort.

Scale

200 million SF of multifamily building stock for potential replication across New York State. 

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
  • System Failure
  • Equipment nearing end-of-life
  • New heat source potential
  • Comfort improvements
  • Indoor air quality improvements
  • Facade maintenance
  • Resilience upgrades
  • Efficiency improvements
Asset Conditions
  • Recapitalization
  • Capital event cycles
  • Carbon emissions limits
  • Investor sustainability demands
  • Owner sustainability goals
Market Conditions
  • Technology improves
  • Policy changes
  • Infrastructure transitions
  • Fuels phase out

The Towers are two of 13 buildings that comprise AHC’s multifamily campus located in the Bronx. Many of the systems at the property, including the piping distribution system, are beyond their useful life and in poor condition, causing leaks and requiring continual repair and maintenance. The campus currently uses a central gas-powered boiler plant to produce steam for heating, cooling, and domestic hot water.

As part of its recapitalization cycle, the property is embarking on a decarbonization journey which will include a comprehensive retrofit of the heating, cooling, and domestic hot water systems, an envelope upgrade, and onsite renewable generation in the form of geothermal and solar PV. 

This project will increase thermal comfort and secure utility affordability for its low-and-moderate income residents, as well as enhance the energy efficiency and climate resilience of the property. 

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Existing Conditions

This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.

Click through the measures under “Building After” to understand the components of the building’s energy transition.

Sequence of Measures

2024

2026

2028

2030

Building System Affected

  • heating
  • cooling
  • ventilation
The Towers Before Illustration
The Towers After Illustration
The existing distribution system and terminal units are beyond their end of useful life (EUL). Install 2 new hydronic loops supplying both heating hot water and chilled water all year round to new fan coil units (FCUs) in apartments.
Install sewage tank and use Sharc Energy heat pumps to produce heating, cooling and domestic hot water (DHW)
Cleaning and balancing of existing ventilation system
Insulate roofs, replace windows and air seal walls.
Drill geothermal boreholes on property land and install ground source heat pumps to produce heating, cooling and DHW
The Towers After Illustration
Take advantage of rooftop space to install solar PV system for clean electricity generation
The Towers After Illustration

Reduce Energy Load 

  • New hydronic distribution: Replace the dual temperature hydronic system with new piping supplying both heating hot water and chilled water simultaneously to provide heating or cooling year-round improving tenant comfort. The measure includes new fan coil units with more efficient motors and designed for low temperature heating hot water to reduce the load on the buildings and facilitate heat pump technology integration.
  • Envelope Improvements: roof insulation, window replacement and air sealing walls 
  • Ventilation Maintenance: balancing and sealing of ventilation system to reduce exhaust air 
  • Controls Upgrades: Install modern control system to automate and optimize new heat pump systems

Recover Wasted Heat 

  • Wastewater Heat Recovery: Recapture heat from wastewater using WSHPs to produce heating, cooling, and domestic hot water (DHW). Use wastewater as heat sink in cooling mode to enable removal of old cooling towers.

Full Electrification 

  • Ground Source Heat Pumps: Drill boreholes on property land and install WSHPs to produce heating, cooling and DHW. Use boreholes as heat sink in cooling mode. 
  • Solar PV: Install solar PV system on rooftop 
  • Electrify Appliances: install electric dryers and cooking equipment

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

$33M

Capital costs of decarbonization.

Avoided Risks

Business-as-Usual Costs

$29.5M + $35k / YR

BAU cost of system replacement.

Repairs & maintenance.

Avoided Risks

Business-as-Usual Risks

N/A

LL97 fines do not apply at this property.

Added Value

Decarbonization Value

$6.7M

Incentives.

Net Present Value

$1.97M

Versus -$1.36M for BAU with difference of $3.33M. 

To confirm the viability of The Towers adopting energy efficiency measures, the project team constructed several discounted cash flow financial scenarios utilizing Net Present Value (NPV) or the total cash flow of the measures taken over a period of time by assuming a discount rate for the worth of money over a period. For comparison, they constructed a baseline for forecasted equipment replacement compared to the Roadmap measures. A comparison of investment costs are as follows: 

  • Baseline Costs: $29.5 million 
  • Measure Costs (Alternative 1): $33 million, $26.4 million (after rebates, tax benefits, etc.)

Using a 7% discount rate over 20 years, the discounted cash flows resulted in relative net present values (NPVs) of -$1.36 million for the Baseline and +$1.97 million for the planned ECMs, a difference of $3.33 million. Based on the analysis, the cost of planned ECMs is a more viable financial investment.

Notably, the costs of business-as-usual in these scenarios do not capture what New York State prescribes as the Social Cost of Carbon (SCC). The SCC is a metric used by countries, states, and other authorities having jurisdiction (AHJ) to place a cost on climate change impacts. New York State firmly defines the SCC as $125/ton of CO2 emitted. The alternative energy system for The Towers, though capital intensive, has clear economic benefits. This and many other climate change impacts such as point pollution, land degradation, human health, and others, are known as intangible decarbonization benefits.

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

Strategic decarbonization roadmap for The Towers.

The measures used in our decarbonization strategy have been strategically planned based on priorities, as well as to optimize energy and carbon reduction. The approach is to reduce loads first to allow for reduced and properly sized new systems. This sequence enables implementation of the measures because it allows thermal loads to be reduced as soon as possible, before electrification of heating and cooling with the ground source heat pump (GSHP) system. Most critical to the success of the plan are the early implementation of the distribution system retrofit and installation of the wastewater energy transfer (WET) system for thermal energy recovery.

Due to the critical nature of the decarbonization work, AHC desires an aggressive implementation timeline for the measures. The work, specifically the piping and fan coil unit (FCU) replacement and WET system installation, is slated to occur 2024-2026. Then in 2026-2028 comes the critical steps of envelope improvements, submetering and control upgrades, and geothermal system installation. The geothermal measure will be a critical step for transitioning The Towers away from fossil fuels because the GSHP system will replace the steam supplied from the gas and oil fed central boiler plant for heating, cooling, and domestic hot water (DHW). This measure will allow the chiller, cooling tower, and steam piping to be fully decommissioned, thereby yielding additional operational and maintenance savings. In 2028-2030, installing the solar PV system will allow for further deep energy savings as it will enable The Towers to have a direct source of clean energy and rely less on the main electricity grid, which needs time to transition to clean energy. Lastly, in 2039-2034, electrifying the appliances will be the last component in completely transitioning The Towers away from on-site fossil fuels while also saving energy by installing high efficiency alternatives and providing health benefits to the residents by eliminating gas stoves.

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Case Study

A Rational Approach to Large Building Decarbonization

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
Asset Conditions
Market Conditions

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

Avoided Risks

Business-as-Usual Costs

Avoided Risks

Business-as-Usual Risks

Added Value

Decarbonization Value

Net Present Value

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

Lessons from New York’s Empire Building Challenge

This article, published in NESEA’s BuildingEnergy magazine (Vol. 40 No. 1), addresses common “decarbonization blind spots” that impede progress and shares insights gained from the incremental methodology and integrated design process pioneered through NYSERDA’s Empire Building Challenge.

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Case Study

Technical Barriers to Decarbonization

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
Asset Conditions
Market Conditions

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

Avoided Risks

Business-as-Usual Costs

Avoided Risks

Business-as-Usual Risks

Added Value

Decarbonization Value

Net Present Value

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

Insights from Empire Building Challenge

Large commercial and residential buildings must overcome various hurdles before implementing deep retrofits or capital projects that help achieve building decarbonization. This section addresses technical barriers and questions often faced by building owners and retrofit project developers.

Decentralized Systems and Tenant Equipment

  • Access to Occupied Spaces.
  • Lease Concerns.
  • Regulatory Limitations of Rent Stabilized Apartments.
    • The building owner is required to provide free heat and hot water.
    • No mechanism to recover investment in new systems is necessary to achieve decarbonization.
    • Buildings are capital constrained.
  • Split Incentives (e.g. tenants pay for energy).

Facade and Windows

  • Work must be completed at the end of facade/window useful life; very long useful life.
  • Building codes.
  • Glazing reduction at odds with aesthetic/marketability concerns.
  • Difficult installing with occupied spaces.
  • Reduce Local Law 11 recurring cost via overcladding
    • Aesthetic concerns
    • At odds with historic preservation
    • Capital intensive
    • Lot line limitations
  • Technology Limitations
    • Need higher R-value/inch for thinner wall assembly:
      • Vacuum insulated panels
      • Aerogel panels/batts
      • Zero-GWP blowing agents for closed cell spray foam (nitrogen blowing agent needs to be more widely adopted)

Ventilation

  • Energy Recovery Ventilation (ERV)
    • Space constraints
    • System tie-in point accessibility/feasibility
  • Rooftop Supply Air (Reznor) Unit Alternatives
    • Heat pump alternatives to eliminate resistance heat
    • Combine with ERV
  • HVAC Load Reduction (HLR) Technology
    • Vent or capture exhaust gases
    • Space constraints
    • System tie-in point accessibility/feasibility
  • Central vs. Decentralized Ventilation Systems
  • Direct Outside Air System (DOAS)
    • Modular perimeter ducted air heat pumps:
      • Competition for leasable space
      • Space constraints
  • Ventilation Points-of-Entry
    • Aesthetic concerns
    • Lot line facades/building setbacks
    • Competition with leasable space
    • Space constraints

Heat Pump Limitations

  • Variable Refrigerant Flow (VRF)
    • Fire and life safety concerns about volume of refrigerant gas located within occupied spaces.
  • Regulatory risk from new refrigerant policies
  • PTAC and VTAC
  • Ducted Supply/Exhaust Air Source Heat Pumps
  • Domestic Hot Water
    • Central DHW Systems:
      • Limited domestic production.
      • Performance not confirmed by independent third parties.
      • More demonstration projects needed.
    • Decentralized DHW Systems
  • More open-source interconnection between devices/interoperability is needed to achieve energy distribution flexibility and capacity expansion:
    • Air source that has a manifold connection to interconnect with water source or refrigerant gas distribution.
    • Interconnectivity/simplified heat exchange between refrigerants/water/air, etc.
    • Other options and add-ons.

Steam Alternatives and Barriers

Below are high temperature renewable resource alternatives to district steam. These alternatives are limited and face barriers to implementation due to cost, scalability, and other factors. 

  • Deep Bore Geothermal
  • Renewable Hydrogen
  • Carbon Capture and Sequestration
  • Biomethane
  • Electric Boilers
  • High-temperature thermal storage
  • Hight-temperature industrial heat pumps
  • Waste Heat Capture and Reuse
  • Fission

Barriers to Electrification and Utility Capacity Limitations

Building Electric Capacity Upgrades

  • Electric riser capacity
  • Switchgear expansion
  • New service/vault expansion/point-of-entry space constraints
  • Capacity competition with other electrification needs:
    • Space heat and cooling
    • DHW
    • Cooking
    • Pumps and motors

Local Network Electric Capacity Upgrades

  • Excess Distribution Facility Charges (EDF)
  • Contributions in Aid of Construction (CIAC)

Gas Utility Earnings Adjustment Mechanisms (EAM) focused on System Peak Demand Reductions

  • Partial Electrification concepts achieve deep decarbonization but do not necessarily achieve peak gas demand reductions (debatable)

Total Connected Loads and Peak Demand drive need for capacity upgrades

  • Demand reduction strategies do not obviate capacity limitations unless the utility accepts the solution as a permanent demand/load reduction strategy.
    • Battery Storage:
      1. Fire danger
      2. Space constraints
      3. Electricity distribution limitations
      4. Structural loads
    • Building Automation/BMS/Demand Response:
      1. Cost
      2. Integration limitations; Blackbox software
      3. Microgrid development cost and lack of expertise
    • On-site Generation:
      1. Space constraints
      2. Gas use; Zero carbon fuels availability is non-existent
      3. Structural loads
      4. Pipe infrastructure

Thermal Storage

  • Space constrains
  • Structural loads
  • Technology limitations:
    • Vacuum insulated storage tanks
    • Phase change material (DHW, space heating)

Geothermal (ambient temperature), Deep Bore Geothermal (high temperature) or Shared Loop District Energy Systems provide cooling and heating with lower peak demand than standard electric equipment

  • Building pipe riser limitations; need additional riser capacity:
    • Building water loops are typically “top down” – cooling capacity is typically located at rooftop mechanical penthouses; cooling towers at roof. Some exceptions to this rule
    • Space Constraints
  • Drilling Difficulty:
    • Outdoor space constraints for geothermal wells
    • Difficult permitting
    • Mud and contaminated soil disposal
    • Overhead clearance constraints for drilling in basements/garages 
  • Shared Loop/Thermal Utility Limitations:
    • Requires entity that may operate in public ROWs and across property lines
    • Utilities are limited by regulations for gas, steam or electric delivery versus shared loop media (ambient temperature water).
      1. Only utility entities can provide very long amortization periods
      2. Utilities are best suited to work amid crowded underground municipal ROWs.
  • Deep Bore Geothermal Limitations:
    • Requires test drilling and geological assessment
    • Seismic risk
    • Drilling equipment is very large – more akin to oil and gas development equipment
    • Subsurface land rights and DEC restrictions

Other Energy Efficiency/Conservation Measures with proven/attractive economics (these measures are limited by lack of capital or knowledge)

  • Lighting with lighting controls
  • High-efficiency electrically commutated motors (ECM)
  • Variable Frequency Drives (VFD) on pumps and motors
  • Retro-commissioning tasks and maintenance

Behavioral Modification

  • Staggered work scheduling
  • Telework

Submetering and billing, potentially creates split incentive between landlord and tenant

Crossover Device or “Magic Box” Technology

These include multi-purpose technology for heating, cooling, heat exchange and ventilation, filtration, and/or domestic hot water.

  • Domestic production and supply chain is limited.
  • Small players operating in this space.
  • Technology is not tested over long operational periods (providers include: Daikin, Nilan, Zehnder, Drexel und Weiss, Minotair, Build Equinox, Clivet).

Zero Carbon Fuel Limitations

  • Green Hydrogen
  • Renewable Natural Gas

Low-Carbon Fuels

  • Biofuel
  • Biomethane

Renewable Energy Procurement Limitations

  • REC Purchasing:
    • NYSERDA monopolizes REC purchasing from renewable energy projects.

Pending Carbon Trading Programs Limitations

  • Deployment timeline is highly uncertain.
  • Price per ton of carbon is highly uncertain and will likely be volatile/low based on previous emissions trading scheme outcomes.

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Case Study

Low Carbon Multifamily Retrofit Playbooks

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
Asset Conditions
Market Conditions

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

Avoided Risks

Business-as-Usual Costs

Avoided Risks

Business-as-Usual Risks

Added Value

Decarbonization Value

Net Present Value

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

These playbooks summarize retrofit strategies that maximize occupant comfort and energy savings through a transition from fuel to electricity- based heating, cooling and hot water systems.

Playbooks are organized by building system— lighting & loads, envelope, ventilation, heating & cooling, and domestic hot water– detailing common existing systems, typical issues, and recommended measures.

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Case Study

Seven Misconceptions About Decarbonization

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
Asset Conditions
Market Conditions

Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

Retrofit Costs

Decarbonization Costs

Avoided Risks

Business-as-Usual Costs

Avoided Risks

Business-as-Usual Risks

Added Value

Decarbonization Value

Net Present Value

An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

Insights from Empire Building Challenge

It is clear today that the use of fossil fuel-fired equipment in buildings has a limited future due to technological advancements, policy changes, ESG requirements, and other externalities. As asset managers, sustainability managers, and their consultants pursue decarbonization plans, misconceptions about decarbonization arise that can delay action and progress. Below is a list of the misconceptions encountered by NYSERDA’s Empire Building Challenge team and our recommended approaches that debunk these inaccuracies. 

1.
Simple Payback Measures

Instead of looking for tangential ways to create value, energy efficiency and decarbonization projects repeatedly fall into the trap of using energy savings (and some may now include carbon emissions fines savings) to justify investments in energy conservation measures. Often, this linear thinking approach yields unattractive investment economics. Alternatively, conduct scenarios analyses including net present value calculations: The lowest net present cost or negative net present value (NPV) over the decarbonization period will help inform the prioritization and selection of energy conservation measures. Demonstrating the return on investment (ROI) and/or internal rate of return (IRR) on the incremental cost of action over a do-nothing baseline will help persuade real estate owners to prioritize these projects. Rather than a simple payback analysis that looks only at the decarbonization path, the analysis should focus on comparing a decarbonization path with a “business-as-usual” path. This approach helps isolate the incremental cost of decarbonization over a business-as-usual approach. 

This type of analysis requires completing a Strategic Decarbonization Assessment (SDA), which is based on a Discounted Cash Flow (DCF) analysis over the decarbonization period. The SDA should include the complexities of a capital refresh, tenant improvements, and non-energy benefits. Asset investment should be in the context of a comprehensive decarbonization roadmap rather than simply reactive maintenance.

2.
One-to-one Equipment Swap with Air Source Heat Pump Is the Best Electrification Option

A one-to-one equipment swap with air source heat pumps, which is typically the first full-electrification option considered, may not be a realistic decarbonization strategy – particularly for owners of large buildings facing various constraints around thermal distribution systems, roof space, tenant disruption, and energy supply. In fact, it is advantageous to determine the building’s need for heat pumps toward the end of the decarbonization road mapping process to ensure that the heat pumps can run optimally. Significantly reducing loads, recovering and reusing heat wherever possible by enabling thermal networking, and using a cascading approach to decarbonizing easy-to-electrify loads are likely advantageous steps to take before installing heat pumps. Systems should be optimized to deliver heating or cooling efficiently over the integrated sum of the year’s diverse conditions, the vast majority of which are at part-load. Efforts to reduce and shift loads can help reduce peak capacity. However, electrification of more difficult peaks may require special consideration within the building’s roadmap and taking a rational approach to resilience and accounting for evolving electric grid or thermal network supply conditions. This is the foundation of Resource Efficient Decarbonization.

3.
Electrify Everything… Immediately and All at Once!

Perhaps because the electrification movement was born in mild-climate California, the cold-climate, tall-building narrative has been incomplete. Decarbonization skeptics suggest that if it doesn’t make sense to electrify everything in one simple move, then it doesn’t make sense to electrify anything.  The reality is that tall buildings in cold climates like New York must overcome space constraints and distribution challenges to provide comfort at peak load conditions without straining the electric grid or requiring oversized, sticker-shock-inducing equipment capacity.

A more suitable slogan for Northeast electrification champions would be “Electrify Everything Efficiently.” Engineers should model building energy consumption data across granular temperature bins (see Figure below) and plan for electrification with “easy” loads like domestic hot water, then mild temperature loads (typically representing 80%+ of total loads), and finally for the extremes. This is the cascade approach. Until a viable solution emerges, a building owner might even keep a small gas-fired boiler and their steam radiators around as a reserve as they learn to grapple with resilient functionality at heating design conditions. Despite global average temperatures increasing, cold snaps may even become more extreme due to a collapsing winter Polar Vortex.

Annual Energy Usage by Temperature Bin

4.
Technology Installed Today Will Be Obsolete Tomorrow

There are plenty of technology-neutral enabling steps to take prior to committing to a particular low-carbon retrofit technology. Buildings are constantly evolving and exist on a continuum unless demolition is planned. Reducing loads, enabling thermal recovery, sharing and networking, and implementing grid interactivity are all priority measures that might take place prior to electrifying heat sources. Consultants also must determine the value of inaction and the value at risk if a building owner decides to do nothing. Balancing this risk with the pace of technological innovation is a delicate analysis and is impossible to conduct without a Strategic Decarbonization Assessment. When in doubt, look to leverage existing infrastructure like using chilled water loops for heating to replace partial loads. Electrifying perimeter heating used during extreme temperatures may be a later priority or absent from the critical path on a strategic decarbonization roadmap. Look to the case studies emerging out of the Empire Building Challenge for more information on this strategy.

5.
My Tenants Don’t Think This is a Priority

Consider the tangential benefits of pursuing decarbonization early. For example, more and more Class A tenants are demanding environmental action from landlords to comply with shareholder environmental, social, and corporate governance (ESG) requirements. Accelerating facade improvements may reduce the need for invasive and expensive maintenance down the line. Indoor air quality, improved comfort, and operability are emerging priorities among all tenant types. 

6.
Electricity Produces Emissions

Yes, but not for too much longer. States are legislating 100% carbon-free electric grids like New York did in the Climate Leadership and Community Protection Act (Climate Act). Modeling total emissions over time using declining electric grid carbon emissions coefficients across multiple decarbonization scenarios is an important task. Phasing in electrification over time and in a strategic way is the only pathway to eliminating on-site emissions.

Chart, line chart

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7.
It’s Too Disruptive and Expensive to Decarbonize a Building All at Once

Achieving carbon neutrality typically requires and benefits from a phased approach versus decarbonizing all at once. Incremental implementation of low-carbon retrofits across a continuum is critical to reaching building operations carbon neutrality in cold climates. Evaluate the cost-effectiveness of phasing and maintaining technology optionality and the risk mitigation benefits these efforts might deliver. Decarbonization efforts fall on a decision-making tree, which evolves as time elapses and technology, policy, or other conditions change; each branch of the decision-making tree is a new decision point. Sustainability and asset managers can plan these intervention points over the decarbonization period.

Chart, diagram

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Case Study

59-17 Junction Boulevard

Updating end-of-life equipment to enhance resilience and decarbonize

This case study was chosen as part of the Empire Building Challenge competition. Click here to learn more about the Empire Building Challenge competition.

59-17 Junction Boulevard, developed by LeFrak Commercial, highlights the crucial intersection between decarbonization and resiliency. The 454,645 square foot, 20-story commercial property located in Queens, NY was built in 1970 and features an inefficient 2-pipe heating and cooling system that has reached the end of its useful life, due in part to damage sustained by Hurricane Ida. 

As part of their participation in the Empire Building Challenge, LeFrak will complete a significant decarbonization project valued at $19.7 million, resulting in the overall reduction of onsite fossil fuels by 2035. The measures aim to electrify and recover heat of thermal loads at the property, immediately reducing site energy use by over 33% from a 2021 baseline. 

LeFrak is a preeminent, family-owned property company that owns and manages an extensive portfolio of real property concentrated in the New York/New Jersey metropolitan area, as well as South Florida, Los Angeles, and throughout the West Coast.

59-17 Junction Boulevard
Investment

25.1 million

Total project investment to install retrofits enabling electrification and heat recovery of thermal loads at the property and reduce site energy use intensity by 33%.

Lessons Learned

Replacing fuel-fired absorption chillers with modular heat pump electric chillers enhances heating and cooling capabilities.

Chiller install
Testimonial

“LeFrak is proud to work in partnership with NYSERDA and the Empire Building Challenge to advance the real estate industry’s ability to decarbonize high-rise buildings. We recognize the importance of leading the path to carbon neutrality and are committed to working together to rethink our building environment.”

John Fitzsimmons
Senior Director, Head of Commercial Property Management
LeFrak Commercial

Lessons Learned

Installation of heat exchangers and critical re-piping enables the core and perimeter of the building to operate independently and provides heat recovery.

Delivery of electric modular heat pumps chillers and heat exchangers

A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

Building System Conditions
  • Equipment nearing end-of-life
  • Damage from events
  • Resilience upgrades
  • Efficiency improvements
Asset Conditions
    Market Conditions

      The plan for decarbonization was developed with short- and long-term needs in mind and was prompted by heating and cooling equipment that has reached the end of its useful life, due in part to damage sustained by Hurricane Ida. This project highlights the intersection between decarbonization and resiliency, in which necessary upgrades can be leveraged to integrate low-carbon solutions and safeguard critical building systems from future climate impacts. The immediate capital work, slated for 2024-2025, has been structured to facilitate the elimination of on-site fossil fuel consumption by the end of the 2035 decarbonization period, with careful consideration given to constructability, importance of tenant disruption, and financial implications.

      Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

      Existing Conditions

      This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.

      Click through the measures under “Building After” to understand the components of the building’s energy transition.

      Sequence of Measures

      2024

      Building System Affected

      • heating
      • cooling
      • ventilation
      59-17 Junction Boulevard Building Before
      59-17 Junction Boulevard Building After
      Replace damaged steam-fired chillers with electric modular heat pump chillers for electric cooling newly piped to the independent core and perimeter hydronic loops of the building
      Install multiple heat exchangers and dedicated VFD pumps to facilitate heat recovery between core and perimeter using electric modular heat pump chillers in cooling mode during the shoulder season
      Auxiliary condensing water connection isolation taps installed to a future campus wide thermal energy network heat recovery source via a heat exchanger
      Expand electrical capacity and provide backup generation for resiliency. The measure will allow additional, layered heat generation needed to meet peak heating loads
      Extract additional heat and cool from outgoing exhaust and redirect back into the building

      Reduce Energy Load 

      • Building Management System (BMS): Install new BMS for better integrated control of HVAC equipment and lower distribution temperature.

      Recover Wasted Heat 

      The existing, inefficient 2-pipe system, which only allows the building to be in heating or cooling mode, will be re-piped to create two separate hydronic zones. This will allow the newly independent loops of the building to exchange rejected heat from the core to the perimeter zone as needed. This piping work will incorporate heat exchangers to possibly connect with adjacent buildings also owned by LeFrak that are mostly residential and create a community thermal network to share loads.

      • Enabling Heat Recovery: New piping work to separate core and perimeter hydronic systems and operate them independently. Install heat exchangers to facilitate heat recovery between core and perimeter using electric modular heat pump chillers.
      • Heat Recovery Ventilation: Install Energy Recovery Ventilators (ERV) to recapture wasted heat and pre-condition fresh air.

      Partial Electrification 

      Beginning in 2024, the existing fossil fuel driven plant will be decommissioned, and a new plant that enables decarbonization will be installed, including modular electric heat pump chillers with cooling and future heating capabilities.

      • Electric Heat Pump Chillers: Replace existing fuel fired steam absorption chillers with electric modular heat pump chillers that can provide heat recovery via dedicated heat exchangers.
      • Thermal Network Connection: Install heat exchangers and auxiliary connection to allow a future connection to a campus wide thermal energy network.

      Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

      Retrofit Costs

      Decarbonization Costs

      $25.1M

      Capital costs of Empire Building Challenge funded decarbonization measures: 9.7M.

      Capital costs of other renovation work: 15.4M.

      Avoided Risks

      Business-as-Usual Costs

      $10.7M + $85k / YR

      Energy cost savings: 8.5k / YR.

      BAU cost of system replacement/upgrades (replacement in kind (non-electric chiller, estimated): 10.7M.

      Avoided Risks

      Business-as-Usual Risks

      $238k / YR

      Avoided LL97 fines starting in 2030.

      Added Value

      Decarbonization Value

      $3.5M

      Empire Building Challenge Incentives: 3M.

      Other incentives: 500k.

      Net Present Value

      $6.5M

      Net difference between the present value of cash inflows and outflows over a period of time.

      The building had an immediate capital expenditure at the start of the project, through the need to replace the existing central heating and cooling plant. The initial scope of work for the plant replacement was installing magnetic bearing drive, centrifugal chillers to avoid costly future LL97 fines projected with their current fossil fuel driven equipment. While this would have alleviated a majority of future LL97 fines, it did not address any of the enabling steps required for future heat recovery which are necessary to support longer term decarbonization goals. The enabling steps are critical as the building explores options for further fossil fuel reduction beyond 2030, such as integration with external thermal networks.

      An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

      Strategic decarbonization roadmap for 59-17 Junction Boulevard.

      Due to external project requirements, this project had a particularly compressed implementation timeline compared to other decarbonization projects. The team evaluated various replacement options over the existing systems to reduce carbon emissions: at the end of the EBC Technical Assistance Phase, ownership reviewed the financial and technical analyses of the decarbonization roadmap options, ultimately deciding to electrify the cooling plant and enable heat recovery from the core zone to the perimeter zone. The central plant work meets the building’s immediate needs, while increasing the resilience of the central plant and allowing for future flexibility and decarbonization efforts. 

      On-site work to upgrade the central plants has already begun and will continue into 2025. This work includes:

      • Replacing damaged steam chillers with electric modular chillers. 
      • Installing a new BMS system to allow better, integrated control of HVAC systems.
      • Redesigned central plant with additional heat exchangers and improved piping layout to separate core and perimeter hydronic systems and operate them independently, enabling heat recovery between core and perimeter using electric modular chillers.
      • Auxiliary piping and heat exchanger allowing a future connection to a campus wide thermal energy network.
      • Expanded electrical capacity and backup generation for resiliency. The measure will allow additional, layered heat generation needed to meet peak heating loads.

       

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      660 Fifth Avenue

      High-rise implements heat pumps and outdoor air systems for decarbonization
      660 Fifth Avenue Case Study

      Case Study

      Empire Technology Prize

      A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

      Building System Conditions
      Asset Conditions
      Market Conditions

      Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

      Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

      Retrofit Costs

      Decarbonization Costs

      Avoided Risks

      Business-as-Usual Costs

      Avoided Risks

      Business-as-Usual Risks

      Added Value

      Decarbonization Value

      Net Present Value

      An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

      The Empire Technology Prize is a $10 million competitive opportunity for global solution providers focused on advancing building technologies for low-carbon heating system retrofits in tall commercial and multifamily buildings across New York State. This NYSERDA initiative, administered by The Clean Fight with technical support from Rocky Mountain Institute, includes a $3 million sponsorship from Wells Fargo. Accelerating low-carbon building retrofits is fundamental to New York State’s national-leading Climate Act agenda, including the goal to achieve an 85% reduction in greenhouse gas emissions by 2050.

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      Case Study

      Intervention Points and Best Practices

      A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

      Building System Conditions
      Asset Conditions
      Market Conditions

      Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

      Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

      Retrofit Costs

      Decarbonization Costs

      Avoided Risks

      Business-as-Usual Costs

      Avoided Risks

      Business-as-Usual Risks

      Added Value

      Decarbonization Value

      Net Present Value

      An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

      Insights from Empire Building Challenge

      Prioritizing Decarbonization Interventions 

      While each individual building has a unique capital improvement plan and timeline, retrofit projects or decarbonization interventions may be organized and grouped by similarity as property owners plan for the future. Below is the overarching hierarchy for decarbonization intervention points according to industry best practices:

      1. Facade Upgrades
      2. Windows Upgrades
      3. Ventilation Upgrades with Energy Recovery Ventilators (ERV)
      4. Maximize the reduction of distribution temperatures
      5. Maximize surface area of terminal units
      6. Supplement 90% of peak load with hybrid electrification strategies
      7. Eliminate peak load “last-mile” with innovative strategies in storage and/or thermal demand response
      • Delay replacement of gas-fired equipment with new gas-fired equipment as long as possible. Rebuild and maintain existing equipment until replacement.
      • Replace all remaining non-LED lighting and include lighting controls at the time of retrofit
      • Seal rooftop bulkhead doors and windows.
      • Add smoke-activated fire dampers or annealed glass to the elevator shaft vent grill in the elevator machine room.
      • Install algorithmic controls on top of the existing boiler control system.
      • Balance steam distribution systems:
        • Identify condensate return leaks.
        • Right-size air vents and master vents.
        • Ensure all radiators are properly draining condensate.
        • Ensure all steam traps are functioning properly.
      • Implement Radiator Efficiency and Controls Measures:
        • Install thermostatic radiator valves (TRV) where possible.
        • Install RadiatorLabs radiator cover systems where possible (integrate with algorithmic boiler control).
      • Balance air supply and ventilation systems using proper air registers, louvers, dampers, and technology like Constant Airflow Regulator (CAR) dampers:
        • Need innovative methods of balancing temperature across commercial office floors (heat shifting and sharing from one building exposure to another, e.g. north vs. south).
        • Balance air supply and return across vertical pressure gradients.
        • Seal vent stack perforations/leaks (e.g. mastic sealer).
      • Increase efficiency of pumps and motors:
        • Add VFD controllers to all pumps and motors.
        • Replace rooftop exhaust fans (e.g. mushroom fans or similar) with electronic commutated motors.
      • Implement algorithmic controls on top of existing Building Management Systems (BMS) in commercial office buildings.
      • Hybrid Domestic Hot Water (DHW) Plants: Add DHW heat pump equipment to an existing gas fired DHW plant.
        • Consider the option to direct bathroom exhaust air to DHW heat pump equipment.
      • Install Energy Recovery Ventilation (ERV) system.
      • Install rooftop solar.
      • Procure New York State-sourced renewable power.
      • Procure biomethane from utility via pilot program.
      • Procure renewable hydrogen blend from utility via pilot program.
      • Develop innovative means of participating in gas demand response:
        • Delay boiler firing with controls or other means.
        • Procure biodiesel blend for fuel switching requirement.
        • Thermal storage and hybrid plants (electrification)
          • DHW electrification (partial or full load)
          • Split system or PTAC partial load heating electrification
      • Add central-control compatible thermostats to apartments and office suites to control decentralized heating and cooling systems.
        • Enable aggregate demand response activity.
      • Fully electrify DHW systems:
        • Air source DHW heat pump.
        • Resistance DHW.
        • High-efficiency thermal storage.
        • Supplement with solar thermal where compatible.
      • Overlaid or insulated masonry facades with high ongoing Local Law 11 cost.
      • Eliminate uninsulated radiator cabinets/niches in exterior walls.
        • Install wall-mounted slim radiators with TRV or other controls.
        • Install RadiatorLabs technology.
      • Begin routine window replacement plan with high-performance windows.
      • Support cogeneration systems with biomethane (injection) procurement.
      • Explore hydrogen (injection) procurement to support cogeneration and centralized heating plants.
      • Develop on-site battery storage systems to manage building load profiles and reduce peak usage.
        • Integrate with an existing on-site generation where compatible.
      • Increase thermal mass/thermal inertia and expand thermal storage capacity using Phase Change Material (PCM) products. Products currently include: ceiling tiles, wall panels, AHU inserts, thermal storage tank inserts:
        • Embrace overnight free cooling.
        • Shift loads associated with thermal demand.
        • Capture and store waste heat.
      • Implement centralized or in-building distributed thermal storage systems to shift thermal loads to off-peak periods.
      • Convert low-temperature heating distribution systems to shared loop systems or geothermal systems; building distribution is already optimized for low-temperature distribution: water source heat pumps, large surface area terminal units (radiant panels, underfloor heat, fan coils, etc.)
        • Interconnect with early shared loop system phases (private or utility-led).
        • Eliminate cooling tower as a primary cooling system (may remain as a backup as feasible).
      • Where necessary, convert high-temperature heating distribution systems to low-temperature distribution systems; systems converted from fin tube to radiant panels, fan coils, or water source heat pumps as feasible.
        • The supplement heat source for hydronic heat pumps with solar thermal technology (water source heat pumps).
      • Embrace consumer products that reduce building loads and peak demand:
        • Appliances with onboard battery storage.
        • Networked smart appliances.
        • Power over Ethernet (PoE) DC-powered, low voltage products.
          • DC power distribution networks make use of on-site renewable energy and energy storage.
      • Advanced DC[1] and AC/DC hybrid Power Distribution Systems[2]
      • Install HVAC Load Reduction Technology:
        • Capture VOCs and CO2 in liquid sorbent.
        • Engage with the liquid sorbent management company to safely dispose of scrubbed gases (carbon sequestration, etc.).
        • Use buildings hosts for negative carbon technology and focusing on direct air capture to achieve larger decarbonization goals (carbon capture and sequestration)
      • Electric Distribution Upgrade Needed:
        • Begin replacement of centralized heating systems with decentralized heating and cooling systems where appropriate. Technology includes: PTAC, VTAC, ducted PTAC, VRF, and similar technology.
        • Replace stoves, ranges, and cooktops with electric equipment: resistance, convection, or induction.
        • Integrate Building Distribution with an advanced electric vehicle (EV) charging network to provide power to parked EVs and to extract power at peak periods (EV owners opt-in for reduced parking rates, other benefits, etc.).
      • Install multi-function glass during window or facade replacement:
        • Install building-integrated PV during facade retrofits.
        • PV glass.
        • Electrochromic glass.
        • Vacuum Insulated glass.
      • Install highly insulated panels at spandrels:
        • Vacuum insulated panels.
        • Aerogel insulated panels.
      • Replace cooling towers with advanced heat rejection technology:
        • Passive radiative cooling technology.
      • Interconnect with 100% hydrogen distribution network.
      • Pair advanced, on-site battery storage systems with hydrogen fuel cells.

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      Case Study

      Whitney Young Manor

      Recapitalization to achieve carbon neutral affordable housing

      Located in Yonkers, NY, Whitney Young Manor, is a notable affordable housing complex with 195 apartments across 234,000 square feet and 12 stories. Built in 1974, the housing complex is now undergoing a $22 million makeover focusing heavily on decarbonization upgrades. This renovation aims to modernize the buildings by improving insulation and introducing a new heating and cooling system that’s energy efficient. These changes are expected to lower the buildings’ carbon footprint, enhance living conditions, and reduce energy costs. The developer, Paths Development LLC, is leveraging the recapitalization cycle of the property to upgrade its infrastructure and include decarbonization measures to meet its climate goals. 

      Whitney Young Manor Building
      Investment

      12 million

      of total investment allocated to bring Whitney Young Manor to carbon neutrality by 2035.

      Project Scale

      Project has potential replication across a portfolio of 51 existing affordable housing developments managed by Paths.

      Original facade
      Testimonial

      “The Empire Building Challenge is enabling Paths to pilot innovative approaches to decarbonization while at the same time helping to preserve affordable housing.”

      Kenneth Spillberg

      Head of Development

      Paths Development LLC

      Emissions Reductions

      This project prioritizes intensive load reduction through envelope improvements and hydronic distribution to improve resident comfort while reducing carbon emissions, utility spend and maintenance costs.

      A baseline assessment is key to understanding current systems and performance, then identifying conditions, requirements or events that will trigger a decarbonization effort. The assessment looks across technical systems, asset strategy and sectoral factors.

      Building System Conditions
      • Equipment nearing end-of-life
      • New heat source potential
      • Comfort improvements
      • Indoor air quality improvements
      • Facade maintenance
      • Resilience upgrades
      • Efficiency improvements
      Asset Conditions
      • Recapitalization
      • Carbon emissions limits
      • Owner sustainability goals
      Market Conditions
      • Technology improves
      • Utility prices change
      • Fuels phase out

      Whitney Young Manor is an aging affordable housing complex with open balconies, inefficient electric resistance baseboard heating, electric wall sleeve AC units, and gas-fired domestic hot water heaters. 

      The project team believes that with care, planning, and the appropriate resources, retrofitting these residential buildings can  better serve  tenants, deliver  environmental benefits, and prove financially feasible for owners. Paths leverages the recapitalization cycle of the property to upgrade its infrastructure and include decarbonization measures to meet its climate goals. 

      This project prioritizes intensive load reduction through envelope improvements and hydronic distribution to improve resident comfort while reducing carbon emissions, utility spending, and maintenance costs.

      Effective engineering integrates measures for reducing energy load, recovering wasted heat, and moving towards partial or full electrification. This increases operational efficiencies, optimizes energy peaks, and avoids oversized heating systems, thus alleviating space constraints and minimizing the cost of retrofits to decarbonize the building over time.

      Existing Conditions

      This diagram illustrates the building prior to the initiation of Strategic Decarbonization planning by the owners and their teams.

      Click through the measures under “Building After” to understand the components of the building’s energy transition.

      Sequence of Measures

      2024

      2025

      Building System Affected

      • heating
      • cooling
      • ventilation
      Whitney Young Manor Building Before
      Whitney Young Manor Building After
      EIFS over uninsulated masonry, new windows, new roof
      New hydronic piping drilled through common areas
      Install 2 ASHPs to produce low temperature hot water and chilled water for in-unit FCUs
      For use during power outages and extreme cold events
      2-Pipe Low Temperature Fan Coils installed in units
      Heat pump DOAS with ERV to recover heat from exhausted air to provide tempered supply air to the corridors
      Install modular WSHPs supplied by hydronic loop
      Install 18,000 gal sewage tank and use Sharc Energy’s heat recovery system and water-to-water heat pump to supplement central ASHPs

      Reduce Energy Load 

      Whitney Young Manor demonstrates the benefits of over- cladding and hydronic distribution to enable heat pump technology: 

      • New hydronic distribution: High efficiency water-based distribution system, lower supply temperature 
        • The new hydronic distribution piping will enable the integration of different heating sources and allow heat sharing between end uses, such as DHW production during cooling season. The construction team plans to pilot cross-linked polyethylene (PEX) piping to reduce cost and improve durability. 
      • Dedicated Outside Air System (DOAS): decouple ventilation from heat and cooling systems 
      • Envelope Improvements: overclad, roof insulation and window replacement
        •  Over-cladding using Exterior Insulation and Finishing System (EIFS) helps reduce heat loss and air infiltration while avoiding façade maintenance costs associated with LL11. This measure is combined with the new Dedicated Outside Air System (DOAS) to make sure adequate fresh air is injected into the building. 

      Recover Wasted Heat 

      The project team plans to integrate different heat sources connected to the central hydronic piping. This includes centralized air source heat pumps, Wastewater Energy Transfer (WET) system and gas-fired condensing boilers as back-up.

      • Wastewater Heat Recovery: Recapture heat from wastewater using WSHP 
      • Energy Recovery Ventilator (ERV): Recapture heat from ventilation exhaust to condition make-up air

      Electrification 

      • Central Air Source Heat Pump (ASHP): Maintain design temperatures for the hydronic loop
      • Water Source Heat Pump (WSHP) for Domestic Hot Water (DHW): DHW production supplied by hydronic loop 
      • Back-up gas condensing boiler: Provide supplemental heat during cold events as resiliency

      Making a business case for strategic decarbonization requires thinking beyond a traditional energy audit approach or simple payback analysis. It assesses business-as-usual costs and risks against the costs and added value of phased decarbonization investments in the long-term.

      Retrofit Costs

      Decarbonization Costs

      $12M

      Capital costs of decarbonization measures. 

      Avoided Risks

      Business-as-Usual Costs

      $1.92M

      Energy cost savings, repairs and maintenance savings, BAU cost of system replacement and upgrades.

      Avoided Risks

      Business-as-Usual Risks

      N/A

      LL97 emissions fines don’t apply at this property.

      Added Value

      Decarbonization Value

      $6.14M

      Incentives from Empire Building Challenge, Low-Carbon Pathways Program, and ConEd Clean Heat.

      Net Present Value

      TBD

      Net difference between the present value of cash inflows and outflows over a period of time.

      Paths Development LLC is a division of Paths, a full-scale, vertically integrated affordable housing developer, builder, and operator. Since 2004, the Paths team has created and preserved high-quality affordable housing across the U.S. that enhances communities and helps residents build better lives. With other 12,000 units across 9 states under management and more than 300 employees, Paths manages a suite of capabilities spanning the entire property life-cycle, including: development, construction, property management, maintenance, and security.

      An emissions decarbonization roadmap helps building owners visualize their future emissions reductions by outlining the CO2 reductions from selected energy conservation measures. This roadmap is designed with a phased approach, considering a 20- or 30-year timeline, and incorporates the evolving benefits of grid decarbonization, ensuring a comprehensive view of long-term environmental impact.

      Strategic decarbonization roadmap for Whitney Young Manor.

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