The average person is unaware of the inner workings of the buildings he occupies. In terms of the water-management systems, when he touches a handle, a faucet, or a knob, he expects a reaction—whether it be the movement of water or a change in air temperature—without a thought as to how it will happen. Behind the faucet handles and air vents are integrated systems that make those everyday actions possible.
While the equipment may be different, plumbing and HVAC systems mimic the anatomy of an athlete. Just as is true of an athlete, fitness is key to success. In the world of commercial buildings, success is predicated on the maximum efficiency of water-management systems.
When the efficiency of a facility’s plumbing and HVAC systems is maximized, building owners realize energy- and operational-cost savings. Optimal efficiency can be achieved through seasonal maintenance and best practices regarding water pumps.
Pumps: the Heart of the System
The comparison of buildings to athletes helps to highlight the role of pumps. Plumbing and HVAC systems function like the circulatory and respiratory systems in a human by transporting heating and cooling water to help address the needs and demands of occupants. Pumps are the heart of these operations, sending water to where it is needed.
In a commercial building, pumps serve a variety of functions:
- Environmental comfort: Water is the most efficient means of heating or cooling a building and ensuring occupants are comfortable. Water-based HVAC systems help to lower costs and provide flexibility for future building modifications. Though they may require a greater upfront investment, they offer the lowest life-cycle cost.
- Potable-water supply: Pumps may be needed to supply adequate potable water to all parts of a building. Pressure-boosting pumping systems can help to ensure adequate pressure is available to all devices requiring water, regardless of the time of day and demand on the system.
- Wastewater removal: Buildings produce two types of wastewater: stormwater and sanitary wastewater. Structure type and structure location relative to city storm and sanitary sewers help to determine whether wastewater needs to be pumped from a building. Proper maintenance of wastewater pumps is critical, as flooding is highly disruptive and destructive.
- Energy recovery: Heat recovery is the term used to describe the capture and re-use of energy that normally would be lost. Energy recovered from waste-heat sources has the potential to reduce fuel costs when used to preheat hot water.
- Re-use opportunities: Reclaimed water and graywater can be used to reduce the amount of potable water consumed by a building. Graywater collected from showers, tubs, lavatories, and drinking fountains can be reused for irrigation with minimal treatment.
Additionally, water-based systems produce the least carbon-dioxide emissions of all available space-conditioning technologies. By facilitating energy recovery and water re-use, they help to reduce overall water consumption, which can be extremely important for regions that experience water shortages.
Checkups and Maintenance
As with any structure—biological or mechanical—routine checkups and maintenance are necessary to ensure all parts are in good working order and functioning at their most efficient. An athlete cannot perform at his or her peak with a broken bone. The same is true with plumbing and HVAC systems. Regular servicing of equipment can help to address malfunctions and inefficiencies.
So, get on a schedule (see sidebars), and bring in a professional to help troubleshoot.
SIDEBAR: Fall, Winter Pump Maintenance
HVAC hot-water heating pumps circulate hot water throughout a building and convert it to warm air at strategic points. Prior to heating season, check the following:
- Mechanical seals.
- Bearings.
- Couplers and shaft alignment.
- Water quality (pH and clarity).
SIDEBAR: Spring and Summer Pump Maintenance
Storm and sanitary wastewater pumps: Inspect stormwater pumps prior to spring, which typically is the start of storm season. Many of these are submersible sump pumps, which are immersed in a basin and, thus, difficult to inspect. Be sure to test the level control that activates the pump.
HVAC chilled-water pumps: Chilled-water pumps circulate cooled water throughout a building and convert it to cooled air at strategic points. Prior to cooling season, check:
- Mechanical seals for leaks. If a leak is detected, replace the seal.
- Bearing lubrication and temperature. Lubrication intervals and lubricant type and grade can vary. Consult product manuals for correct application. Bearing temperature can be measured using hand-held infrared sensors. Measure temperature at normal operating intervals so spikes can be gauged and potential failures addressed.
- Pump- and motor-shaft alignment to prevent uneven wear of couplings. Signs of uneven wear include piles of rubber shavings beneath flexible couplers. Although shaft alignment can be checked with a straight edge, a laser alignment system is recommended.
- Water quality. Checking water pH and clarity is critical to ensuring the highest-quality water.
SIDEBAR: Year-round Pump Maintenance
Potable supply water pumps are among the most critical pumps in a building. If one goes down, the entire building may be without water and unsuitable for occupancy. The good news is that most pressure-booster pumping systems are designed with full or partial backup.
Service pressure-booster pumps regularly to ensure they are in good working order. As with hot- and cold-water heating pumps, check for mechanical-seal leaks, bearing wear, and poor coupler alignment.
Energy-Saving Opportunities
Motors that drive pumps consume significant amounts of electricity when operating. In most cases, application of a variable-speed drive can help to save energy by better matching pump performance to the needs of the system.
Savings are dependent on the type of pumping system, the cost of electricity, and the hours of operation. Over time, pump performance degrades from normal wear and tear, and replacement may be advantageous over the costs associated with extending equipment life through service.
Today’s pumps offer advanced hydraulic efficiencies and integrated controls with variable-speed drives that improve efficiency and help to save energy.
Summary
The plumbing and HVAC systems of a building are similar to the biological systems of the human body: They are dependent on care and maintenance to remain strong, healthy, and functioning at peak performance.
Proper maintenance of pumps helps to build immunity against unnecessary wear and tear on a system. Routine checkups help to ensure pumps will operate as designed for many years. Additional energy savings can be obtained through retrofits and upgrades to overall systems.
Consult manufacturer websites for more specific product recommendations.
Mark Handzel is vice president, product regulatory affairs, and director, HVAC commercial buildings, for Bell & Gossett, a Xylem brand. He has more than 30 years of experience applying pumps in commercial and residential buildings.
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