Case Study

78 Herkimer St

Thermal battery transforms historic Brooklyn building

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

Project Highlights

Lessons Learned

Leading-edge Sunamp thermal batteries use phase change material to store heat energy at densities 4 times greater than water, allowing in-unit equipment placement, thereby eliminating building-wide distribution piping and stand-by losses while saving space compared with traditional cylinder-style water heaters.

Lessons Learned

Most of Chartered Properties’ building retrofits will recapture rejected heat pump compressor heat created as a by-product of space conditioning and transfer it to pre-heat domestic hot water.

Cost Savings

85%

Sunamp thermal storage creates a reservoir for off-peak generated domestic hot water and hydronic space heating, at an 85% cost savings compared with peak demand electricity.

Step 1

Step 1: Examine Current Conditions

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
Tenant load change
Efficiency improvements

Asset Conditions

Repositioning
Tenant turnover/vacancy
Carbon emissions limits
Building codes
Owner sustainability goals

Market Conditions

Technology improves
Utility prices change
Fuels phase out

43% of all New York State apartment dwellings are similar to the 3-7 story joisted masonry buildings being decarbonized by Chartered Properties. Developing an energy-saving mechanical design geared toward ease of installation and maintenance were paramount considerations when planning this project. Distinguished from large, centralized rooftop projects, these small-sized, modular components installed unit-by-unit capture the desired efficiencies. Each building has a unique layout, occupancy, and economic profile, and a primary goal of this project is to test the flexibility, cost effectiveness, energy efficiency and maintenance benefits that a modular apartment-by-apartment approach offers across diverse floor plans. Chartered’s retrofits provide test installations that are widely replicable in the state’s oldest, and most obsolete housing. Monitoring hardware will provide data to vet the approach and inform future retrofits of 442,601 similarly-situated apartment buildings across New York State.

Step 2

Step 2: Design Resource Efficient Solutions

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

2025

Building System Affected

heating
cooling
ventilation

Cooking Electrification with Induction Stoves

Step 3

Step 3: Build the Business Case

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.

Decarbonization Costs

Business-as-Usual Costs

Business-as-Usual Risks

Decarbonization Value

Net Present Value

Cost details forthcoming

Energy retrofits that save money must also improve the property’s environmental footprint. When paired, these objectives accomplish Chartered Properties’ energy-value investment proposition. Replacement mechanicals improve COP, while also reclaiming and storing waste heat. This new equipment, powered by cleaner energy purchased at costs below existing carbon fuels, fulfills the firm’s targeted economic and environmental value propositions. Carbon neutral investment within Chartered Properties portfolio will remove all fossil fueled equipment currently serving the buildings domestic water and heat production.

Installation equipment and labor costs are paid weekly in installments ranging from $3,000 to $5,000 closely matching building net cash flow thereby avoiding the difficulty, expense and time associated with third-party debt financing. This ‘matched funding’ has advantages even on small installations costing, as little as $60,000. Assuming a 6% interest rate, aligning building cash flow with project costs saves $300 monthly interest that can be redeployed toward the retrofit rather than debt service. Recapture of retrofit outlays begins sooner and are accelerated by the 85% discount for off-peak electric and further compounded by the 100% electric-heat conversion rate replacing the 70%-80% gas to heat generation of the decommissioned system. This staged financing approach may also offer data points useful to others. Developing an affordable pathway that matches diminutive revenue streams, with installation timelines flexible enough to fit within small-building budgets is essential for statewide decarbonization. Tracking the financials along with Chartered’s staged mechanical implementation can provide these metrics and hopefully generate a template style installation schedule geared to cash flow that may prove useful as a blueprint for others going forward.

Strategic Decarbonization Action Plan

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.

Statewide, 3-7 Story apartment buildings provide a huge decarbonization opportunity for rapid transition to healthier mechanicals. The modular, unit-by-unit approach to implementation with costs geared to building cash flow is designed to redress both the physical and economic hurdles for these owners. The equipment selected for the trial is easy to install and maintain further reducing obstacles. Determining how to efficiently combine these elements into a replicable protocol is the guiding objective of Chartered’s retrofit undertaking.