Many organizations today are working to identify ways to meet decarbonization goals, reducing their dependence on carbon-rich fossil fuels such as coal, natural gas, oil, and propane. Their goal: to dramatically reduce their emissions of the greenhouse gases implicated in climate change, while, hopefully, also decreasing their energy costs and bolstering organizational reputation at the same time.
For most organizations, the production of heat is the largest individual application of energy, and space heating for buildings is one of the largest components of that output, accounting for more than $20 billion each year expended by the commercial sector. With most of this heat generated by fossil fuels, building heating applications are therefore also among the largest components of the carbon footprint culpability of nearly any operation.
Efforts to reduce the carbon emissions associated with building heating has recently led organizations to consider replacing fossil-fuel fired furnaces and boilers with electric-driven options. For many, this is the next step in the decarbonization of heating, building on the prior step of replacing traditional boilers with the more efficient condensing-type. Now, with the growing use of renewables on the supply-side, there is additional opportunity for decarbonization on the demand-side by replacing the boilers and furnaces altogether with heat pumps for an even larger improvement in operating cost, emissions, and decarbonization performance.
This electrification of building heating can provide significant benefits at the location, allowing operators to not only reduce carbon emissions, but also remove onsite fossil fuel flue-based NOx (nitrogen dioxide) and SOx (sulfur dioxide) emissions, improve energy efficiency, and reduce operating costs. This evolution also provides a building’s power providers with the opportunity and flexibility to meet increasing demand with carbon-free renewable sources rather than fossil fuels, thereby further developing the potential to exponentially improve their carbon footprint. This possibility, of course, is not available to utilities providing fossil fuels only.
Unfortunately, operators currently experience occasional barriers and limitations in taking these otherwise highly beneficial measures. Electric-driven boilers, perhaps the simplest option in terms of retrofitting infrastructure, utilize electric resistance heat, which is quite inefficient. Electric heat pumps — the more preferred choice, on the other hand, currently most commonly consist of equipment based upon constant speed positive displacement screw compressor technology, but, while more efficient, often offer an ROI payback period that is somewhat longer than many organizations require to justify investment. Further, the more efficient heat pump technologies, based on operating temperature limitations, have previously required also changing out demand-side equipment to enable operation at significantly lower heating temperatures.
Fortunately, there is a new advanced compressor technology emerging that is specifically geared for heat pump applications and that enables significant gains in efficiency and decarbonization while eliminating many of these former limitations. These oil-free, magnetic bearing centrifugal compressors are currently involved in several test projects and yielding impressive results.
Modeling suggests that, when used in electric heat pump applications, oil-free, magnetic bearing centrifugal compressors can provide up to 40% greater energy efficiency and lower resulting emissions compared to constant speed positive displacement screw compressor-based heat pumps, driving significant operating cost savings and substantial reduction in carbon footprint. When compared to variable speed positive displacement screw compressors — a more efficient heat pump technology, modeling suggests that a significant 15-20% reduction in emissions and 10-15% reduction in energy costs can be realized. And, when replacing or as an alternative to a high efficiency condensing boiler, the operating costs can be reduced by 40% and the CO2 emissions by 64%. This emissions reduction estimate increases as renewables are integrated into the power grid.
Further, these comparative improvements can further increase over time because oil-free, magnetic bearing centrifugal compressors maintain performance over the long term, whereas the performance of positive displacement screw compressor-based heat pumps can degrade as much as 10% in the first five years and 20% within the first 10. This degradation process is driven by a combination of the mechanical degradation of the positive displacement compression sealing process as well as oil-driven heat transfer degradation.
In short, this is an innovation that will be of significant interest to heat pump designers, manufacturers, energy management consultants, and, especially, any commercial or industrial facility interested in decreasing their carbon footprint, increasing energy efficiency, and reducing heating costs.
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For more discussion on decarbonization policies and trends in North America, check out our EnVisioneering Exchange podcast, episode 5.
For more discussion on the potential of heat pump and oil-free technology to address the technology gap caused by decarbonization, check out our EnVisioneering Exchange podcast, episode 6.
