Learning From the Past for More Sustainable Buildings

While significant progress has been made in recent years on measures to decarbonize buildings, decisions are often made based on criteria that do not consider the long-term sustainability of the building and compatibility with future energy assessments. Of course, no one can predict the future, but looking at some decisions made in the past by engineers and architects can help us identify approaches that allowed certain buildings to adapt better over time.

Take New York City as an example. Many residential buildings in use today were constructed in the late 1800s and early 1900s. At the time, the city’s electrical infrastructure was underdeveloped, but in contrast, oil and coal were readily available. It is not surprising that architects and engineers chose to use fossil fuels to generate steam for heating buildings. Since steam did not require an electric pump to be distributed, it was undoubtedly the logical choice at the time. Additionally, to transport the steam, many buildings were equipped with a one-pipe system — steam and condensate coexisted in the same pipe, saving the need for a dedicated condensate pipe. This was certainly a good decision in terms of cost, as well as the materials required for construction.

Unsurprisingly, this concept, innovative in its time, came with its share of challenges. It is estimated that, today, 25% of the multifamily buildings in New York are still equipped with one-pipe systems. Whether in terms of comfort, control, or efficiency, however, these buildings have struggled to stand the test of time.

When looking at this building stock through the lens of decarbonization, we realize that the decisions made over a century ago are now increasing the risk, cost, and environmental impact of retrofits and renovations. The interventions are even more complex since these buildings are still inhabited. In some cases, the task is so challenging that owners prefer not to make improvements.

Lessons Learned

There are a few lessons here for us today. First, a sustainable building is one that has an energy distribution network. Even if this system was originally designed for fixed heating or cooling loads, by using heat pumps, it is possible to convert these networks into energy vectors, allowing for the recovery and reuse of excess heat instead of releasing it. The second lesson is that buildings with access to more than one energy source (electricity and gas) enable electrification while ensuring resilience and limiting the impact upstream on electricity production and distribution.

We learned these lessons while decarbonizing a multifamily building, the International Tailoring Company Building, built in New York City in the 1920s and converted to residential use in the 1980s. This project, which achieved an 80% reduction in greenhouse gas (GHG) emissions, required major interventions in inhabited areas.

In contrast, our project at the Montreal Olympic Stadium is an example of work in a facility with an energy infrastructure that has stood the test of time so far. Since the Stadium was designed for the 1976 Summer Olympics, engineers had designed a cold-water distribution system. In 2018 Ecosystem was able to repurpose this system to provide heating with heat pumps. The steam network was converted to hot water, and combined with gas and electric boilers, the project achieved an 83% reduction in GHG emissions while minimizing waste and the need for new materials for this major renovation. The Stadium continues to be an example of the integration of architecture and energy production/distribution systems, standing the test of time.