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New York Backs Major Building Decarbonization Initiative

Today, few buildings in the world are carbon neutral, or produce net-zero carbon emissions, but as the electric grid decreases its reliance on fossil fuels, the building stock must wane its dependence on carbon producing systems inside buildings in turn. For owners of large buildings in dense urban environments, implementing the necessary retrofits to shed carbon can be daunting, but technology and design advancements are guiding the way.

The Empire Building Challenge (EBC) is a newly-launched $50 million public-private partnership headed by the New York State Energy Research and Development Agency (NYSERDA). The challenge seeks to support replicable and scalable retrofit approaches to achieve high-rise, low-carbon buildings that combat climate change and create jobs for New Yorkers.

While there are a variety of strategies for buildings to achieve carbon neutrality, the initial global research effort is focused on two key decarbonization-enabling technology areas—energy distribution and thermal storage.

 

Energy Distribution and Thermal Storage

Switching out building systems that use fossil fuels with efficient electric alternatives (e.g. heat pumps) is a key part of the decarbonization solution which gets a lot of attention. However, many large buildings lack either the necessary building electrical capacity or building energy distribution capacity necessary to accommodate electrification strategies. Electrical system upgrades can be cost-prohibitive or technically infeasible and many existing buildings don’t have thermal distribution or ventilation systems compatible with effective electric solutions.

Energy distribution and thermal storage are often overlooked, but crucial first steps towards a carbon neutral future.

Energy distribution: Energy distribution is the delivery of heating, cooling and electricity from a source to each space. Innovative technologies and design approaches can reduce heat transfer losses, allowing for reduced equipment size, increased efficiency and curbed building peak loads all while enabling efficient electric alternative systems. Energy distribution technologies enable:

  • Higher density delivery: Moving to a higher-density heat transfer media can significantly reduce energy consumption of distribution systems. For example, switching to a hydronic (water-based) system with pumps could require 5–10x less energy to move the same amount of heating or cooling than a forced air system.
  • Optimal temperature of supply: Electrification relies on equipment compatible with low temperature supply (e.g. heat pumps, waste heat recovery) and there is a need for distribution systems that accommodate that. When using fossil fuels for heating, buildings can use high temperature supplies. However, with electric heat pumps there are issues of inefficiency or complete incompatibility that can be solved through the lowering of hot water supply temperature.

Thermal storage: Thermal storage refers to storing energy in the form of heat or coolth as opposed to electricity. Often this is done in water tanks, ice tanks, phase changing “thermal batteries,” or leveraging a building’s mass to store this energy. Thermal storage enables:

  • Equipment downsizing: When building owners can shift their thermal consumption across a 24-hour average load using storage, instead of requiring full heating capacity during the coldest hour, they can buy smaller/cheaper equipment and run it more efficiently.
  • Electrification: Heat pumps can be challenged to keep up with peak heating loads without a backup system on the coldest days of the year. Thermal storage can eliminate or reduce the need for auxiliary/backup heating needed to meet these peak demands.
  • Demand flexibility: As heating becomes electrified, thermal storage allows for the shifting of large building loads resulting in significant carbon, cost, and health benefits.

Retrofitting office towers and residential high rises to be compatible with net-zero carbon sources will require innovation, awareness, and market catalysts by public and private players. New York is leading this effort and unveiled the Empire Building Challenge during the 2020 Climate Week.

 

The Empire Building Challenge

The Empire Building Challenge is designed to address innovation gaps in the market by partnering with high-profile real estate owners who are committed to decarbonizing their portfolio. The challenge calls for applicants to pledge to decarbonizing one or more of the buildings in their portfolio by 2035. Selected partners will then be eligible to submit low-carbon retrofit proposals for up to $5 million in funding from NYSERDA.

The EBC aims to demonstrate replicable retrofit pathways that will help set the standard for the next decade of real estate investments needed to transition New York’s tall buildings to low-carbon emissions levels and higher energy performance. By working with leading real estate portfolio owners and best-in-class solution providers, NYSERDA hopes to leverage the innovation of the private sector to overcome technical barriers, spur product development, and create jobs for New Yorkers.

Exciting New Technologies

Working alongside Third Derivative and Elementa Engineering, RMI is developing a database of energy distribution and thermal storage products, technologies and design concepts/configurations at all levels of technology readiness—ranging from best-in-class US, best-in-class global, to emerging (research and pre-commercialization stage). Informing the market of the best products available will hopefully attract investment and accelerate adoption in these focus areas where there is a knowledge and investment gap.

The goal of the database is to identify the current state of the industry inside the thermal storage and distribution spaces.  This may advise future EBC partner projects and other NYSERDA decarbonization initiatives in hopes of serving designers, real estate developers/owners, policy makers, and the investment community.

There is some amazing innovation in the building energy distribution and thermal storage & thermal inertia space, here are a few examples:

Building Energy Distribution

  • Radiant heating & cooling: Instead of traditional A/C units, radiant systems circulate chilled/heated water through ceilings or walls. They absorb or provide heat through radiative heat transfer without the need for energy-intensive fans systems or voluminous air-duct networks. Recent developments include increased heat transfer efficiency and membrane integration to eliminate condensation risk.
  • Hydronic system additives: With domestic hot water and heating systems shifting towards water distribution, innovators have developed fluids which keep heat transfer surfaces clean, reduce surface tension and improve heat transfer.
  • Hybrid variable refrigerant flow systems: Tall buildings require lots of comfort maintenance, but there are increasing restrictions to the amount of refrigerant allowed in buildings due to its linked environmental issues. To prevent the use of excess refrigerant, these hybrid systems replace refrigerant with water between the outside unit and the indoor units—all while allowing simultaneous heating and cooling to different parts of a building.
  • Heat exchanger advancements: Compact, low-cost heat exchangers are being 3D-printed with polymers. This allows for more efficient water-to-water, water-to-air and air-to-air heat transfer with greater heat exchange through counterflow and increased surface area.

Thermal Storage & Thermal Inertia Enhancements

  • Phase Change Material (PCM): Phase change material can be installed within building structures or in thermal distribution designs to actively stabilize temperatures. Similar to ice, phase change materials can store a large amount of energy with minimal temperature change, allowing for buildings to more effectively regulate their climate. PCMs are being developed for applications ranging from solid-to-solid thermal insulators to pumpable slurries for distribution systems.
  • Thermochemical Storage: Thermochemical storage allows for thermal energy to be stored by leveraging the unique properties of specific compounds that absorb and release heat when combined or separated. This has potential to provide long-duration, energy-dense thermal storage.
  • Topping Slab: The existing thermal mass of a building can be leveraged by exposing slabs and other concrete or masonry structures in the building. Retrofitting in radiant heating in a topping slab (e.g. a thin layer of concrete poured over top of existing floor slab) is a simple and effective way to both enable lower energy distribution (via low temperature hydronic radiant heating) and provide the capability to use the existing building mass as a thermal “battery.”

From a holistic perspective, in addition to individual technologies, both the design of the overall system and the planning of how to implement a retrofit over time is critical. Leasing structures are often long-term (e.g. the most common NYC commercial lease length is 10 years) and tenant vacancies rarely overlap, so retrofitting these large commercial buildings in a phased approach is critical.

Some building owners are phasing in decarbonization/electrification technologies floor-by-floor, aligning the retrofits with tenant turnovers in order to achieve carbon neutrality without extensive occupant disruption. The installation of water loop heat pumps and other technologies in a staged approach minimizes the building owner’s exposure to the risks and capital strains associated with whole-building gut retrofits.

The Empire Building Challenge is a terrific way to promote technologies and designs while facilitating networking across the range of participants in the building community from researchers to building operators and owners. NYSERDA efforts to transform the marketplace for low-carbon retrofits are integral to EBC. RMI is excited to support this effort and help surface some of the innovation happening all over the world.

 

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