By Arjun Bhatia

Often when we think of energy systems, we think of those that deliver electricity, petroleum, or natural gas. However, the past century has also seen the rise of a new energy system, right beneath our feet: district energy.

Fundamentally, district energy is the centralised production of steam, hot water, and cold water, which is then cycled around to service a network of buildings, the district. This replaces the traditional setup, in which each building has its own boilers and air conditioning units, resulting in space savings, higher overall efficiency, lower greenhouse gas emissions, and little to no utility and maintenance costs.

McMaster University’s reputation for groundbreaking research and innovation is reflected in an on-campus, or rather, under-campus district energy system that provides heating and cooling to buildings across McMaster. The primary feature of this system is the Combined Heat and Power Generation. The same natural gas that provides electricity has its waste heat reclaimed to power cold water exchangers and generate steam, which is then pumped to buildings around campus to be used for space heating, domestic hot water, or air conditioning. This unique system reclaims the thermal energy that would otherwise be lost, thereby reducing our overall carbon footprint [1].

Not only is this system valuable for providing utilities to the campus, but the data it provides has also been the subject of multiple studies. One such study, conducted by the Department of Mechanical Engineering, involved the development of models to more efficiently operate during the month of October, a major transitional period as a result of changing temperatures. McMaster’s district energy system allowed the researchers to not only develop, but also implement and test these models. The researchers were able to conclude the study with a nearly 90% reduction in carbon emissions during a two-week period. This not only helps the university, but proves practices that can be applied to similar systems across southern Ontario [2].

In 2009, McMaster University played a major role in the propagation of these innovative energy systems, partnering with Hamilton Community Energy to build one at McMaster Innovation Park, a research and entrepreneurship hub affiliated with the university [3].

The system is built around a network of geo-exchange pumps, which rely on the relative stability of the underground to allow water to be heated in the winter and cooled in the summer, simply by circulating it through buried heat exchangers. [4]. This decreases the system’s yearly input energy, which comes from boilers or electric chillers, most of which are powered by a secondary array of solar-thermal panels that heat water using the sun’s energy. All of this comes together to provide clean heating and cooling to nearly 500 000 square feet of buildings on campus. More than that, the very nature of the system allows it to be easily expanded, with the central facility currently in full growth mode [3].

While district energy does not always come from completely carbon-free sources, it provides other sustainable benefits. It can be thought of as a transition and a bridge to achieving complete carbon neutrality, utilizing waste heat and decreasing the amount of fossil fuel required to maintain comfortable temperatures. Additionally, as seen with McMaster’s system, district energy can be implemented in unique ways, best suited to the location where it is built. Thanks to the ingenuity of institutions like McMaster, we keep moving forward towards a greener, brighter future, and district energy is just one of the stepping stones along the way.

References

[1] “CampusEnergy2020 Student Video Contest - McMaster University”, International District Energy Association [Online]. Available: https://youtu.be/_gYIzO7-0Dk. [Accessed: Oct. 31, 2020].

[2] R. Rogers, V. Lakhian, M. Lightstone, and J. S. Cotton, “Modeling of Low Temperature Thermal Networks Using Historical Building Data from District Energy Systems,” in Proceedings of the 13th International Modelica Conference, Regensburg, Germany, March 4–6, 2019, 2019, vol. 157, pp. 543–550, doi: 10.3384/ecp19157543.

[3] “McMaster district energy project a leading example of innovation”, Association of Power Producers of Ontario [Online]. Available: https://magazine.appro.org/news/ontario-news/5007-1487812504-mcmaster-district-energy-project-a-leading-example-of-innovation.html. [Accessed: September 25, 2020].

[4] G. Miller, “Building Momentum: Provincial Policies for Municipal Energy and Carbon Reduction”, Environmental Commissioner of Ontario, Toronto, Canada, 2012 [PDF]. Available: https://www.auditor.on.ca/en/content/reporttopics/envreports/env12/2012-Energy.1.pdf. [Accessed: Oct. 31, 2020].

McMaster's Hidden Energy System