Case Study

345 Hudson

Nordic design principles applied to New York real estate

345 Hudson, developed by Hudson Square Properties (HSP), provides a roadmap for sustainable practices by applying the Nordic design principles of holistic energy recycling and electrification. The 17-story commercial property located in Manhattan, NY was built in 1931 and features a mid-tier energy rating, aging heating system burning natural gas, and recurring carbon emissions fines starting in 2035.

The comprehensive retrofit takes advantage of tenant turnover as an opportunity to upgrade the building’s infrastructure to new, carbon-efficient, energy cost-saving technology and completely decarbonize the 856,000 gross square foot property. This project will demonstrate the power of thermal networking through an innovative approach by which heating and cooling is shared between tenants throughout the building and eventually between neighboring buildings.

Hudson Square Properties is a joint venture with Hines, Trinity Church Wall Street, and Norges Bank Investment Management, that owns 13 buildings totaling 6.3 million square feet in the Hudson Square Neighborhood.

345 Hudson

Project Status

Planning

Under Construction

Monitoring & Evaluation

Emissions Reductions

90%

345 Hudson will achieve a 30% EUI reduction and 90% carbon emissions reduction by 2035 with its decarbonization roadmap.

Lessons Learned

The analysis examined opportunities to reuse, recycle, and balance energy flows via hydronic-based HVAC retrofits at multiple scales of renovation.

345 Hudson
Testimonial

“The carbon reduction and energy efficiency strategy at 345 Hudson, one of our flagship properties, exemplifies Hudson Square Properties’ stewardship and commitment to the long-term strength of our neighborhood. 345 Hudson will provide a roadmap for sustainable practices throughout our portfolio and beyond.”

Sujohn Sarkar

Managing Director, Asset Management

Trinity Church Wall Street

Emissions Reductions

A water source heat pump system is accompanied by a new, highly efficient energy recovery ventilation system to minimize energy waste.

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
  • Comfort improvements
  • Indoor air quality improvefments
  • Efficiency improvements
Asset Conditions
  • Repositioning
  • Tenant turnover/vacancy
  • Carbon emissions limits
  • Investor sustainability demands
  • Owner sustainability goals
Market Conditions
  • Market demand changes
  • Policy changes
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The Hudson Square partnership is committed to future-proof its flagship property by upgrading its building infrastructure while meeting legislative climate goals and staying competitive in the commercial office market. The project team brought together a consortium of global solution providers and engineering expertise to develop a long-term retrofit plan to minimize energy usage and carbon emissions.

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

2022

2023

2024

2025

2026

2027

2029

Building System Affected

  • heating
  • cooling
  • ventilation
345 Hudson Building Before
345 Hudson Building After
Reusing existing condenser loop for both heating and cooling by converting to ambient temperature hydronics
Remove steam radiators and water source Direct Expansion cooling units and install water source heat pumps, pumps, controls, thermal storage and hot water fin tube for 4 floors
Central plant to maintain design temperatures for hydronic loop
Provisional connection to the neighboring new building with geothermal piles
Fresh air supply with minimum 85% heat recovery
Fresh air supply with minimum 85% heat recovery
Potential envelope improvements
Phase in tenant floor work based on tenant turnover lease
Phase in tenant floor work based on tenant turnover lease
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Applying the Nordic design principles of holistic energy recycling and electrification to make decarbonization technically and economically feasible over time. This design approach follows a circular systems philosophy to reduce heating demand by recovering and redistributing heat from high-energy areas to low-energy areas, rather than simultaneously cooling and heating different zones. Heat is moved to or from different floors, and only then is energy introduced to the system via air source heat pumps. 

Reduce Energy Load and Recover Wasted Heat

Developing a hydronic loop operating at ambient temperatures by converting the existing condenser water riser. The ambient loop enables future optionality with the integration of different heat sources and takes advantage of simultaneous heating and cooling opportunities between spaces and floors to reuse otherwise wasted heat.

  • Ambient Loop Hydronic Spine: high efficiency water-based distribution system, lower supply temperature and heat sharing between floors/zones
  • Dedicated Outside Air System (DOAS) with Energy Recovery Ventilator (ERV): decouple ventilation from heat and cooling systems, and recapture exhaust air energy to condition fresh air
  • Tenant Conversion: install floor by floor WSHPs and convert to hydronic low temperature heating and high temperature cooling
  • Window replacement (provisional): reduce air infiltration and reduce energy loads

Partial Electrification: right-size heat pump

Leverage the high efficiency of heat pump technologies, enable grid interactivity, and take advantage of future low-carbon electricity production planned by the state.

  • Central ASHP + Adiabatic Fluid Cooler: heat supply and heat rejection, maintain design temperatures for ambient loop

Full Electrification: replace/remove peak load equipment

  • Thermal Storage: leverage heating hot water and chilled water storage for peak load
  • Thermal network connection to neighboring building: heat sharing capability and leverage geothermal piles in the property next door
  • Decommission natural gas boilers

Other Project Highlights

  • Floor-by-floor replacement of packaged terminal cooling units and steam heating with a comprehensive water source heat pump system significantly reduces heating and cooling needs by recycling heat from different spaces in the building 
  • A more sustainable and circular approach consists of:
    • Leveraging Energy Recovery Ventilation (ERV) to reduce conditioning loads
    • Separating fresh air delivery and conditioning from heating and cooling systems by using a Dedicated Outdoor Air System (DOAS)
    • Recycling existing sources of heat within the building during the cold weather rather than rejecting it to the atmosphere.
    • Utilizing heat pumps to satisfy remaining heating loads in buildings and fully eliminate the use of fossil fuel combustion
  • New systems can be phased in over time: Rather than retrofitting the entire building, work can be done on a floor-by-floor basis, which is easier on the budget, allows for greater flexibility and is less disruptive to existing tenants. It is estimated that full-floor tenants vacate spaces every 10 to 15 years.

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

Central ASHP and Adiabatic Dry-Cooler.

Tenant Conversions 1-3 with WSHP and 4-pipe system.

Connection to neighboring 555G. 

Central DOAS + ERV.

Window Replacement (provisional). 

Avoided Risks

Business-as-Usual Costs

Energy costs savings.

Repairs & maintenance savings.

Avoided Risks

Business-as-Usual Risks

$204k / YR avoided LL97 fines starting in 2030.

Added Value

Decarbonization Value

Empire Building Challenge incentive.

Utility program incentive.

Net Present Value

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

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Using a phased approach, Hudson Square Properties (HSP) spreads costs across the term of their decarbonization project, incorporating key milestones like equipment end-of-life and tenant turnover to take advantage of previously planned capital expenditures. HSP’s phased approach was informed by the Strategic Decarbonization Assessment (SDA) tool, a long-term financial planning tool for building owners to manage emissions and energy use. Developed for NYSERDA, the SDA tool has been piloted by the first EBC cohort and will be continually revised based on feedback from these partners, producing a resource that will help the broader real estate investment community compare business-as-usual pathways to proposed improvements over time, and develop a detailed Discounted Cash Flow (DCF) model of different investment scenarios. The SDA tool is designed to help owners move away from reactive decision-making and towards proactive planning to simultaneously optimize for operational expenses, net operating income, and emissions reductions. The phased retrofit plan provides long-term financial value to Hudson Square Partners, transforming 345 Hudson into a green asset—a class-A building with no legislative risk and very little tenant disruption risk. The hydronic heating infrastructure allows HSP to meet Local Law 97’s building emissions targets, saving an estimated $204,000 each year starting in 2030. In the near-term, these low carbon systems deliver health and comfort benefits and act as a key differentiator for prospective tenants in a commercial market still rebounding from the devastating impacts of COVID-19.

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 345 Hudson.
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Key to HSP’s strategy was understanding how to meet aggressive climate targets while addressing the practical objectives of their tenants—stable temperatures, fresh air, and reliable equipment—without placing too much onus on tenants to devise their own solutions or diligently manage their own consumption. To devise this approach, HSP divided building systems into three distinct spheres of ownership and influence. The first sphere encompasses the heating, cooling, and air distribution equipment under tenant control (e.g., radiators, fan coil units, etc.). The second sphere includes equipment commonly installed and maintained by the landlord, but controlled by the tenant (e.g., air conditioning units). The third sphere covers the core building infrastructure, under full control of the landlord, like cooling towers, boiler plants, and primary air handling units. This framework identified a major opportunity area in which to address carbon and energy goals: equipment supplied by the landlord but controlled by the tenant. Given this, the core objective was to create a scenario in which the landlord provides the solid grounding—such as the thermal network—for tenants to condition their spaces most efficiently. With this core functionality in place, tenants are afforded efficient systems performance simply by occupying the space and tapping into the building infrastructure. Incidentally, projected long term savings will be dependent on tenant plug loads and equipment fit-outs. The potential saving values displayed above are based on best-case scenario and CLCPA carbon projections.

As floors are phased in and more tenants take advantage of the thermal network, the amount of energy recycled across the building increases, incrementally improving the efficiency of 345 Hudson. By 2035, once fully implemented, whole-building energy use would be expected to drop by more than 30%. Total building carbon emissions would fall 90%, compared to a pre-retrofit baseline, with reductions increasing towards 100% as New York’s electric grid becomes fully renewable. These reductions reflect both emissions avoided by capturing 11GWh of waste heat currently rejected by the building (e.g., via cooling towers), and via the application of high-efficiency heat pumps. With a fully deployed thermal network and energy recovery ventilation, modeling reflects a scenario in which only 4 GWh of energy would be rejected. Notably, post-retrofit peak heating and cooling loads would fall dramatically—by 92 and 63% respectively—reflecting the significant benefits of capturing, sharing, and recycling heat across floors. The thermal network is key to electrifying buildings via heat pumps, as it reduces floor-level energy demand, allowing for smaller capacity heat pump systems.

345 Hudson’s 10-year deployment plan first targets improvements to the building’s core infrastructure, then phases in tenant retrofits, floor by floor. Select vacant floors will be retrofitted up front, with the hope of providing showcases to prospective tenants and their engineering staff to witness engineering solutions applied in practice—a critical step in moving the market given the systems’ novelty in New York. From there, additional floors will be phased in during periods of tenant turnover. As the project progresses floor by floor and use of the thermal network expands, heat pumps will supplant existing packaged terminal units and efficiency will improve dramatically. Updated floors will effectively become energy producers engaging in intra- floor heat exchange, rather than receivers of linear energy supply, benefiting the overall system. By 2025, HSP aims to connect the ambient loop at 345 Hudson to the neighboring building at 555 Greenwich, to share loads as needed and take advantage of its geothermal system. By 2030, the building will operate using only electricity, and take full advantage of the fully formed thermal network across all floors. With all floors connected, the thermal inertia (the energy stored within the hydronic network itself) of the whole building will often be substantial enough to store or release energy in response to changing utility rates or renewable energy generation—importing or exporting heat energy when needed, particularly during peak demand conditions. Reactive to grid demands, this solution allows the building to become an asset to the grid rather than simply a consumer.

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Technical Barriers to Decarbonization

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More

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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Low Carbon Multifamily Retrofit Playbooks

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More

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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Empire Technology Prize

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More

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

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More

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

Thermal Energy Networks for Decarbonization Webinar

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More
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New engineering design means and methods are needed to enable and accelerate adoption of low-carbon retrofit technologies. Efficient heating and cooling energy systems are widely available but underused due to lack of knowledge and thermal system interaction.

Decarbonization requires adapting distribution systems designed for legacy thermal supply to electric and renewable thermal energy systems. New design strategies are emerging which can help alleviate space constraint issues, provide peak thermal capacity, optimize operational efficiencies, utilize waste heat, and reduce the need for oversized, electrified thermal energy systems creating retrofit cost compression. The latest research on thermal energy networks focuses on utilizing heat and cold more sustainably by creating innovative components and control strategies for thermal systems. 

In this Empire Building Challenge webinar, Cary Smith and Garen Ewbank from The GreyEdge Group provide perspectives on designing efficient thermal networks for decarbonization. The recorded discussion focuses on low temperature distribution, electrification with advanced heat pumps, thermal storage integration, and thermal interactive buildings.

The materials below were part of a presentation given on Jun 18, 2020, as part of the Empire Building Challenge, in partnership with the GreyEdge Group.

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Case Study

Advanced Building Construction Collaborative Case Studies

Project Status

Planning

Under Construction

Monitoring & Evaluation

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
Learn More

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.

Learn More

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
Learn More

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.

Learn More

These case studies cover projects that will dramatically reduce carbon emissions with deep energy retrofits for affordable multifamily housing in the Boston area. Deep energy retrofits dramatically reduce carbon emissions. These renovations transform affordable housing to be highly energy efficient, all-electric, powered by clean renewable energy, and renovated with materials low in embodied carbon. These projects are part of the Advanced Building Construction Collaborative’s demand aggregation. This work aims to demonstrate streamlined deep energy retrofits and retrofits using advanced building construction techniques to accelerate the adoption of this work in the market.

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