Design Considerations for Pressure-Boosting Systems in Commercial Buildings

Design Considerations for Pressure-Boosting Systems in Commercial Buildings

More than 60 years ago, the late Dr. Roy B. Hunter developed a system for calculating water loads in commercial buildings. The estimated water demand of fixtures (water closets, sinks, etc.) is given a value called Fixture Units which have an equivalent demand load in Gallons Per Minute (GPM). The Fixture Units and Demand Load relationship is known as Hunter’s Curve and is still the basis for plumbing system design today.

Hunter’s Curve can be effectively used to calculate total system demand, but it has a glaring flaw. There is no consideration for diversity in the system demand. Using Hunter’s Curve for the basis of design of a Pressure Boosting System results in a pump system sized for all fixtures being used simultaneously, a scenario that will likely never happen. The pumps are grossly oversized for partial-demand conditions which make up 90% or more of total operation, causing poor system control and unnecessary wear on the pumps and piping system. In addition to Hunter’s Curve, Cougar USA uses field experience and data collection for system design.

To generate an accurate demand load profile, we gather as much information as possible about the building. The type of building has a huge impact on the load profile; even with similar fixture units, hospitals, hotels, schools, and office buildings will all have different load demands throughout the day and week. Special applications, the height of the building, locations of equipment, and potential future expansion are all factors in creating the right Building Load Profile. Once the system requirements are determined, we must make the right equipment selection.

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Building Assessments for Energy Savings and System Performance Improvements

Building Assessments for Energy Savings and System Performance Improvements

In 2017, about 39% of total U.S. Energy Consumption was consumed by the residential and commercial sectors. In a commercial building, HVAC equipment (i.e., 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 any time 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 oversized and incapable of performing well under partial-load conditions, which accounts for 90% or more of the total operation.

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Why We Need to Conserve Water

Why We Need to Conserve Water

When you see photographs of Earth taken from space, water seems abundant. Most of that water, though, can’t be used for drinking or for growing crops. In fact, only 1 percent of all the water on the planet can be used to support human life since most of the Earth’s water is undrinkable salt water. Even some of the fresh water is unavailable for our use because it’s frozen solid.

In the last century, the world’s population tripled, and water usage by individuals increased six fold. As the population continues to rise, the need for sufficient supplies of freshwater will become more urgent, and competition for the available water is likely to increase

The United Nations estimates that nearly one-third of the world’s population will be facing water shortages by the year 2025. Without enough water, diseases will spread more easily, and less food can be grown.

Competition over water supplies can lead to local or international conflicts and possibly war.

Even in places where fresh water usually remains abundant, conserving water makes us better prepared for unexpected emergencies. Water conservation also saves money for both individual families and the community as a whole.

How Much Water Do We Use?

Every day, people use 10 billion tons of freshwater worldwide. Water usage varies widely by country, with the United States using the most water per capita. According to the EPA, Americans use an average of 88 gallons of water every day per person in their homes.

Simple Steps To Use Water More Effectively

Small changes in your daily habits can create big savings in water usage:

  • Turn off the water when you brush your teeth. All that running water adds up, probably more than you think. This simple step can save more than 200 gallons of water per month.
  • Takes showers instead of baths. A bath can use up to seven times more water than a shower. Keep your showers short — do your daydreaming elsewhere.
  • Wait until the dishwasher is full before you run it.
  • Avoid using a hose when you have alternatives. You can use a sponge and bucket to wash your car and a broom to sweep your driveway.
  • Don’t water your yard under a hot midday sun when most of the water will be lost to evaporation. Early mornings and evenings are better.

Repairs and smart purchases can turn yourhome into a water-conserving powerhouse:

  • Be diligent about fixing leaky toilets. A toilet leak can waste as much as 200 gallons a day, the equivalent of 50 flushes. Ouch!
  • Install low-?ow shower heads and water-saving aerators for your faucets. Using water-conserving devices can reduce your water usage by at least 20 percent and can save an average of $380 annually per family.

Sufficient water supplies are crucial not only for individual use — for drinking, cooking, washing and so on — but also for industry and agriculture. Without conservation, the planet may be facing a crisis unlike any seen before. Many steps that can be taken to conserve water are simple and can be started right now.

At Cougar USA we are proud to partner with GRUNDFOS who pushes the boundaries of possibility in energy efficiency and water conservation.