Cougar USA Blog

Building Assessments for Energy Efficiency and System Performance Improvements

Oct 2, 2018 4:22:00 PM / by Tim Zacharias

 

In 2017 about 39% of total US Energy Consumption was consumed by the residential and commercial sectors. In a commercial building, HVAC Equipment (ie. chillers, boilers, cooling towers, etc) and Lighting are the biggest targets for energy savings, but the capital costs for improving these may be prohibitive. There are many opportunities for energy savings and building performance improvements with other systems in commercial buildings.

Pumps are used in a variety of applications in commercial buildings, and 90% of them work inefficiently. There are three main reasons for pump inefficiency - pump type, size and controls. The proper combination of pump type, size and control will ensure the best system performance and lowest energy costs. Unfortunately, most pumps installed today are either improperly applied or sized and use outdated controls.

Domestic Water Pressure Boosting Pump Systems are required anytime the city water pressure is too low to deliver water to a commercial building. Mid to high-rise buildings almost always have pressure boosting systems, and many single-story restaurants and medical facilities require high water pressure for special applications. In our experience, these systems usually suffer in all areas of inefficiency. Most are designed using fixture unit counts and maximum flow demands without looking at diversity factors and partial usage loads. These calculations cause pumps to be over-sized and incapable of performing well under partial load conditions, which accounts for 90% or more of the total operation.

Even with the right pump type and size selections, high system performance is impossible without good controls. Variable Frequency Drives (VFD’s) and integrated controllers will optimize the pump operation to meet changing building demands, only running the pumps as needed to maintain constant pressure to the building. Even with the perfect combination of pump size, type and controls, the most efficient pump is one that is not running at all.

Another key component to the Pressure Boosting System is a Hydro-pneumatic Tank or Bladder Tank. Bladder tanks are installed in the system piping either at the pump system discharge or off the main riser on upper floors of a building. A bladder tank with a proper air charge is vital to the pump system’s Low Flow Shutdown Sequence, a feature that will turn the pumps off during periods of little or no water demand. Allowing the pump system to shut down and still maintain water pressure to the building will greatly reduce energy costs and reduce wear and tear on the water system components (pumps, piping, pressure reducing valves, etc.).

The energy savings potential with Pressure Boosting Systems in commercial buildings is 60%-90% in most cases. An assessment of a buildings' Pressure Boosting System will review the existing pump system information, but also account for the building type, size, special applications and potential for demand changes. Once these factors are reviewed a new pump system can be selected, and the energy consumption calculated in comparison to the existing system. All the information is documented in a Building Assessment Report, provided at no charge by Cougar USA.

If you are interested in a Building Assessment, please contact us here.

 

Topics: Pressure, Energy Savings

Tim Zacharias

Written by Tim Zacharias