Historically, steam has always been easier to produce than electricity — burning fuel to evaporate water is much simpler than exciting electrons. For this reason, most buildings built at the beginning of the 20th century were developed around steam distribution. Today, many university campuses are a testimony to this heritage.
Steam to hot water conversions, once a seemingly inconceivable goal for higher education facilities in North America, is being recognized as an attainable and implementable solution based on the success of several high-profile pioneers:
In 2015, Stanford University (15M ft2) completed a conversion of its first-generation steam system to a third-generation hot water system, resulting in overall cost savings (20%), water savings (18%), and GHG reductions (50%).
|University of British Columbia
In 2015, UBC (15M ft2) completed a conversion of its first-generation steam system to a third-generation hot water system, resulting in operational and energy cost savings ($5M/yr), thermal efficiency improvement (24%) and GHG reductions (22%).
|University of California, Davis
In 2017, UC Davis (11M ft2) initiated a process to convert its first-generation steam system to a third-generation hot water system, hoping to save an estimated 30%-50% in distribution losses, avoid spending $98M of planned maintenance costs on the aging steam system, reduce O&M costs by 42%, while cutting GHG emissions by 30% and getting closer to its 2025 net-zero commitment.
In 2017, Brown University (6M ft2) initiated a project to convert its first and second-generation steam/high temperature water system into a third-generation low temperature system, resulting in energy savings ($1M/yr or 11%), and contributing to its overall goal of reducing GHG emissions by 42%.
|University of Rochester
In 2004, University of Rochester (12M ft2) initiated a process to convert its first-generation steam system to a third-generation hot water system (70% completed as of today), resulting in thermal losses savings (24%).
While some are heralding the advent of hot water systems as the future of network heating, it is important to remember that systems have evolved in several stages over more than a century of innovation, and will continue to do so in the decades to come:
|1930’s||2nd||High temperature hot water (> 212˚F)|
|1980’s||3rd||Medium temperature hot water (< 212˚F)|
|2020||4th||Low temperature hot water (120-140˚F)|
Early in the 20th century, district heating was exclusively steam, but multiple advances in heating networks made heated hot water (HHW) increasingly common, beginning with high temperatures, and eventually modulating to lower temp hot water. Today, there are discussions of a “next generation” (here “5th”) that would integrate both heating and cooling in a single water-based district network.
Marc Couture is a certified project manager and CEM who has worked with dozens of campuses in North America; below he looks at the reasons that have led Facility Managers to take on the challenges of a steam to hot water conversion.
“At first glance, steam, with its high energy density, seems to be the perfect vehicle to carry energy across large distances while using minimal electricity. However, steam distribution can also lead to major system inefficiencies.
Because steam is often produced at high pressure to transport energy over large distances, when it arrives at the point of use, the temperature is always higher than what is needed to heat. Steam also flashes when brought back to atmospheric pressure, creating additional energy and water losses that weigh down network efficiency. Maintenance of steam systems is critical to ensure uninterrupted operation: steam traps need regular maintenance, condensate pumps and tanks must be replaced at regular intervals, and pressurized distribution piping inevitably springs leaks.
Operation of a steam network is also a critical and complex task that requires 24/7 staff. Despite investment in highly trained operators, campus spaces all too often end up overheated, and it is not uncommon to see windows propped open in dormitories, staff offices, and classrooms, even in the dead of the winter.
Given all these factors, a conversion to hot water can generate significant savings in both consumption and O&M. Moreover, a low-temperature hot water system allows integration of additional high-efficiency and/or renewable heating technologies such as heat pumps.
Is your campus a good candidate for a hot water conversion? Here are some factors that might indicate it is:
In all instances, steam systems are complex, but if you’ve answered “Yes” to two or more of the above, it is probably worth speaking to an experienced engineer to learn about the benefits a hot water conversion could bring to your campus.”
This is the first mini-article in the series. We’d love to hear your feedback on what is important for you.
Future topics include: