4 FM quick reads on HVAC
1. Repair A Pump, Or Replace It?
Today's tip is to know when it's time to repair a pump or to replace it. The first step is to understand its performance level. High-efficiency pump systems are designed for specific applications such as water treatment, condensate return, boiler feed water, chiller water in closed systems, water towers in open systems, and chemical proportioning.
Managers and technicians have a number of tools and tactics to gather essential data on pump performance. Technicians can compare baseline readings to subsequent readings to check for wear of the impeller, casing wear plates, and wear rings. Low or erratic pressure differences can indicate loose belts.
Managers must consider both in-house maintenance capabilities and company policy. Some managers opt to repair as long as the pump casing remains in good condition, which can be decades. Technicians simply replace rotating or worn parts as needed, and depending on the in-house maintenance shop, they may be able to make many of the needed parts.
One approach is that optimum service life occurs when cumulative maintenance labor and material costs equal a pump's replacement cost. Managers can use a formula to calculate a pump's optimum service life in hours and can compare optimum hours to actual operating hours.
An hour meter or service-hours recorder attached to the pump can help accurately determine actual hours. The service recorder is the best option because it accumulates operating hours and sorts them into idling hours and hours under load — valuable data for evaluating the effectiveness of the pump design. When actual hours exceed optimum hours, the unit is replaced. Company financial policy also affects the repair-or-replace decision. Managers must expense parts for rebuilding in the year purchased, but they can capitalize and depreciate replacement pumps over several years. With either option, managers need to watch for upgrade possibilities to newer, more energy-efficient designs. Upgrading the design of a pump or drive can help defray the upfront costs through energy and reliability savings.
2. Tankless Water Heaters Can Provide Big Savings
Today's tip is to consider tankless water heaters for energy savings. Water-heating systems in institutional and commercial facilities typically consume more energy than any other system except HVAC. As a result, even small gains in efficiency can lead to large savings.
More manufacturers are offering a range of new tankless water heaters — also known as instantaneous or demand systems — that provide hot water only when necessary.
Tankless water heaters use highly efficient technology to transfer heat instantly to cold water as soon as demand occurs. When a building occupant turns on a hot water faucet, cold water enters the inlet of the tankless heater and flows through a copper coil, energizing the burner to provide temperature-controlled hot water.
Fueled by propane or natural gas, tankless water heaters offer operating costs that are 30 percent lower than natural gas storage-tank units and 40 percent less than electric storage-tank units. They also require less space, and stored water does not have to be reheated.
An electronic ignition lights the gas burner without a pilot light, so no gas is consumed when the system is dormant.
The typical capacity of a tankless water heater is 2-5 gallons per minute. For larger-capacity systems, a manifold arrangement links units. Condensing technology captures any exhaust gas heat and returns it to preheat incoming cold water, thereby increasing thermal efficiency to as high as 98 percent.
One new electric coilless, tankless heater comes with a rating of 2.5 gallons per minute at a 45-degree temperature rise or 1.7 gallons per minute at 65-degree temperature rise. Voltages for tankless water heaters range from 110 volts to 277 volts.
The necessary size of a unit depends on the user's water flow and the required temperature rise. Typical utility water is 60 degrees, and the typical desired temperature for hot water is 100-120 degrees. In this case, the temperature rise required would be from 40 degrees to 60 degrees. If the water heater serves a kitchen sink with a water flow of 1.5 gallons per minute, then the heater's required capacity is a maximum of a 60-degree rise at 1.5 gallons per minute.
3. How To Save Energy In Large Retail Organizations
Today's tip is about how to save energy when you manage a large portfolio of retail facilities. The key, say experts, is to put a system in place that gives the ability to standardize, analyze and prioritize energy efficiency best practices, and then, energy efficiency data across the portfolio.
To do so, keep in mind, technology is your friend. Many leading retail organizations - like Walgreens and Nike - have installed energy management systems at their stores. These systems can be centrally monitored so that facility managers know if, say, there's a problem with the HVAC system before the store manager would. Additionally, the system can provide technicians with initial diagnosis of the problem. Or, in a best case scenario, a facility manager can tell the store manager how to fix the problem without requiring a technician call.
It's also possible to use the EMS to gradually ramp up HVAC and light levels in the morning, and turn them back down slowly in the evening. This, combined with the other energy-savings strategies available by using an EMS, can save anywhere from 10-33 percent on energy at each store, says one Nike facility manager.
It also helps to standardize setpoints and lighting levels within facilities. That way, when you analyze energy data, it's much easier to tell which facilities are underperforming - and in which specific energy-using areas. Additionally, many organizations hire a third-party company to manage and pay its energy bills - and to give them warning if suddenly a bill is way too high. Then, the forensics regarding why a particular bill is too high can begin.
4. Identifying Energy Rebates Delivers Bottom-Line Benefits
I'm Steve Schuster, associate editor of Maintenance Solutions magazine. Today's topic discusses energy rebates.
Since the 1970s, utility companies have offered commercial and institutional customers rebate and incentive programs. The utilities' goal is to reduce demand-capacity requirements they otherwise would have to make up by expanding their generation and distribution systems. These rebate programs provide utility customers with incentives. Customers install energy-efficient equipment and systems, and the result is lower purchase or installation costs via cash rebates or discounts.
Today, rebate and incentive programs still are going strong, and the time has never been better for maintenance and engineering managers to undertake retrofit projects in their facilities targeting energy efficiency. Some utilities offer incentives to install specific, energy-efficient products, such as lighting, motors, and cool roofs.
Other incentives are based on achieved savings, and still others encourage facilities to take part in specific operational strategies, such as demand response and retrocommissioning.
By understanding the specific goals of utility rebate programs and lining up incentives targeting the most appropriate facility retrofits and upgrades, managers can deliver benefits to their organizations' bottom lines.
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