Yesterday’s state-of-the-art steam heating systems will benefit from an upgrade to the innovative heating technology developed by Leanheat. This technology lowers energy use and costs. It does this by getting steam heating systems to run more efficiently.
Unlike hydronic systems which can easily regulate supply temperatures, steam systems always boil water to make steam. Making steam from hot water requires what’s known as a phase change (liquid to gas). Boiling water through this phase change requires a lot of extra energy*, so to wasting the energy, it’s important to limit the amount of steam produced to as close to what’s necessary to maintain comfort as possible. Steam systems are very sensitive to systemic heat loss because there’s a high temperature difference between the steam and the much lower temperatures around the system. Latent heat loss is costly, and drags down system efficiency to a much greater degree than is the case in the aforementioned hydronic systems, for example. For larger steam systems, there’s also an energy consuming vacuum pump that runs to distribute the steam. So the overall energy footprint of these systems is high.
Steam systems as they were initially constructed contained only passive energy saving technology. They relied on pipe insulation and good boiler design. But because getting even a little bit of heat through the building requires expending a lot of energy, any cycling on and off, plus overshoot effects lead to very inefficient operation.
Today’s steam systems typically operate with the first generation of active efficiency improvements. Outdoor temperature, together with a heating curve are used to limit the amount of time the boiler produces steam. For example, milder days require less heat, so by using the outdoor temperature as a factor to limit the time that steam is produced in each cycle, the costly waste of latent heat (see below) that results from overshoot (and thus overheated rooms and opening of windows) is partially avoided. The downside of this control technology, outdoor reset, is that it’s not able to account for outdoor temperature changes ahead of time, so a conservative buffer is required, which has a cost in lower efficiency.
What Leanheat technology does is take this concept of active energy saving quite a bit further, with more and better factors used to determine the amount of steam produced by the boilers. For example, rather than base the heat production of a long-lag heating system on the outdoor temperature right now, Leanheat factors in where the outdoor temperature is going (based on weather data), solar effects (e.g. expected sunshine or cloud cover), windchill effects, and so on. It also factors in how quickly room temperatures change when the boiler is running.
As a result of the Leanheat upgrade, less of a temperature buffer is required, and temperatures are more consistently comfortable throughout the building. The system also runs more efficiently, lowering costs.
More Reading
Read more about this topic in the blog post on outdoor reset here, and in the context of a building’s Unique Energy Fingerprint here.
And how lower energy costs effect property values here.
*It takes about 8,000 BTUs of energy to turn a gallon of boiling water into steam. An 80% efficient steam boiler would require over 10,000 BTU to make steam from a gallon of boiling water. The energy in the steam, know as latent heat, is given off as it condenses in the pipes and radiators.