With so many systems poorly installed and with maintenance so often neglected, ventilation systems in previous eras were often seen as the source of problems and little else. But today, a mixture of technological advancements and the migration of products from other markets places highly efficient systems that provide exemplary air quality and comfort within reach of virtually every building.
The days of balancing indoor air quality against energy use are over, with modern systems decoupling ventilation from cooling, utilizing high performance energy recovery ventilation (ERVs), and dedicated outside air systems (DOAS) that allow for high volumes of fresh air while drastically limiting the loss of heat and humidity. Decoupling ventilation from the heating and cooling systems is a key element of the Resource Efficient Decarbonization (RED) framework and a critical phase in producing low carbon buildings with the highest quality indoor environments.
During this High Rise / Low Carbon series program developed to support the Empire Building Challenge and other NYSERDA programs, hear from critical leaders in this field as they discuss how these innovative ventilation systems are addressing critical needs across all segments of the building sector, while also providing the foundation for full electrification.
Moderator
Benjamin Rodney, Vice President, Construction, U.S. East Region, Hines
Presenters
Daniel Bersohn, Associate, BuroHappold Engineering Benjamin Rodney, Vice President, Construction, U.S. East Region, Hines
Speakers
Vinca Bonde, Sales Director, Energy Machines Grace Kolb, Mechanical Engineer, AKF Group Tony Abate, Vice President and Chief Technology Officer, AtmosAir Miguel Gaspar, Vice President/Group Leader, Loring Consulting Engineers Dr. Marwa Zaatari, ASHRAE Distinguished Lecturer, Partner at D-ZINE Partners, enVerid Systems Advisory Board Member
A Rational Approach to Large Building Decarbonization
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.
This presentation covers green building and sustainable communities provisions in the Inflation Reduction Act including tax credits, rebates, grants, workforce training, and technology procurement.
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:
Fire danger
Space constraints
Electricity distribution limitations
Structural loads
Building Automation/BMS/Demand Response:
Cost
Integration limitations; Blackbox software
Microgrid development cost and lack of expertise
On-site Generation:
Space constraints
Gas use; Zero carbon fuels availability is non-existent
Structural loads
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).
Only utility entities can provide very long amortization periods
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)
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.
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.
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.
Learn how to maximize benefits from the Inflation Reduction Act (IRA), the Bipartisan Infrastructure Law (BIL), and related federal policies and incentives.
The Inflation Reduction Act (IRA) is the greatest investment in US economic growth and climate action in our lifetimes. Together with related bills, its benefits will be far-reaching, including nationwide economic stimulus, cleaner air, improved health, new jobs, progress toward climate goals, and more. This dashboard hosts content on the opportunity and background of these laws, how they can be effectively implemented, success stories, and key tools.
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.
High Rise / Low Carbon Event Series: Financing Deep Retrofits
Short term return-on-investment calculations are a frequent barrier to better performing buildings, leaving the many benefits of decarbonization out of reach for building occupants and exposing owners and investors to the future risks of holding a stranded asset. Future proofing buildings from anticipated regulations–from carbon emissions to human health–requires longer term thinking and innovative financing models.
A number of organizations are undertaking processes that account for the net-present-value of retrofit measures, and are benefitting from new tools that allow comparisons of various phasing options.
During this High Rise / Low Carbon series program developed to support the Empire Building Challenge and other NYSERDA programs, panelists will discuss exploring how to move beyond simple payback analysis to allow value over time to guide decisions and enable the efficient phasing of building improvements, which will hugely enhance comfort and health while also meeting the goals of our City and State climate action plans.
Opening Remarks
Greg Hale, Senior Advisor for Energy Efficiency Markets, NYSERDA
Moderator
Sadie McKeown, President, Community Preservation Corporation (CPC)
Panelists/Presenters
Lane Burt, Managing Principal, Ember Strategies Grayson Hoffmann, Investment Manager, Norges Bank Investment Management Erangi Dias, Director of Business Development, NYCEEC David Davenport, Managing Director, NY Green Bank
