4 FM quick reads on HVAC
1. Data Loggers, Temperature Guns Make HVAC Troubleshooting Easier
Temperature and humidity data loggers are relatively small battery-powered devices that can be tucked into the most obscure areas and can log thousands of data points. Depending on the task's requirements, technicians can set them to take a data point every second, every five minutes, or even every hour. These simple, easy-to-use devices provide flexibility and versatility, and they are relatively inexpensive. The least expensive devices have USB connections for downloading data. Newer wireless and web-accessible models offer automatic access and the ability to connect devices accessible through one access point.
Once, we had a dispute over whether or not a thermostat actually worked. A glove-wearing, perpetually cold person was convinced the system was set to freeze people out of the building, while the always-hot person insisted there was no way anyone could possibly stand the space being any warmer. A data logger settled it all by showing the thermostat, in fact, did work correctly and controlled the space as programmed. The issue was deemed personal. Gloves continued to be worn.
In another case, a building space experienced unusual, daily temperature fluctuations. Many theories arose, but no resolutions. While the building controls system could provide a great deal of temperature data, it was not the right information. Enter the data loggers. Technicians place data loggers throughout the system and in the space. After several days of monitoring, technicians downloaded the data and trended it. It became clear that the system had several issues, some of which related to the system and some to the controls. With the issues identified, the manager was able to implement the most effective solutions.
2. Factors to Consider When Choosing a Boiler and Water Heating Training Program
Just as there is a range of training formats available for boilers and water heaters, managers have options when it comes to program providers. Determining the most suitable provider for the facility depends on the manager's goals. For example, a number of different providers, such as those who conduct seminars or have online programs, can handle refresher training on the basics of boiler and water heater operations.
More specific training, such as would be required to learn the details of operating and maintaining an advanced boiler-control system, is often best handled by training representatives from the manufacturer.
Managers can start the selection process by getting a list of references from the prospective vendor or provider and talking with people who actually went through the training to better understand their experiences.
For each program being evaluated, managers must consider a number of factors. If the program is held at a remote location, what are the travel costs? Can people attend different sessions, or will all operators and maintenance personnel have to attend the same sessions? How often does the provider offer the program?
If the program is to be held in the facility, what does it cost to bring in the trainers? Does the facility have the necessary space and equipment? Can managers honestly expect operators and maintenance personnel to attend the sessions without interruption or being called away for an emergency?
3. In Boilers, Retrocommissioning Can Address Energy Inefficiency
Today's tip from Building Operating Management comes from James Piper, a contributing editor for Building Operating Management and Maintenance Solutions magazines: A retrocommissioning process can identify and address areas of energy inefficiency in boilers and water heaters.
The retrocommissioning process begins with a detailed review of the boiler or water heater, including data on equipment installed, connected loads, the critical nature of the loads, maintenance history, and operating performance.
Besides installation errors, operators might have made changes to the installation over the years. Of particular interest are changes they implemented to correct maintenance issues that are preventing the unit from operating as efficiently or effectively as intended.
Next, facility managers need to review maintenance records for the boiler and consider whether technicians have performed maintenance according to manufacturer recommendations or bypassed certain features to circumvent operational issues. They also need to determine whether the boiler has required more maintenance as it has aged, and they need to identify operational and maintenance issues.
Technicians need to check and test safety features to ensure proper operation. They also must measure the boiler's efficiency under different loads and verify the boiler's control system operates properly.
Once technicians have completed the test and managers have analyzed the results, managers will be able to identify the steps operators and technicians can take that will improve efficiency and performance. These steps can range from small changes in operating procedures to large overhauls of boiler components. Managers then will be able to estimate the cost and time needed to take these steps and evaluate their options.
The results of data-gathering and testing will be a road map managers can use to improve equipment operation. It will provide a list of recommended tasks, along with relative costs. Managers can implement some steps without interfering with the boiler's operation. Others will require careful scheduling because of the needed shutdown and interruption of service.
Retrocommissioning is not necessarily a one-time task. Facility managers must be ready to repeat the process to ensure the boiler or water heater continues to operate efficiently. The timing of the process will depend on the application, as well as the condition and size of the installation.
4. How to limit contamination on cooling-tower performance
One common issue with cooling tower operation is contamination. The environment in which cooling towers operate exposes them to a range of contaminants. Inorganic solids such as dust, dirt, sand, and silt are introduced into the tower from the atmosphere and the tower's water supply. These solids collect in the tower basin, erode circulation-pump impellers, clog spray nozzles, and form scale on heat-transfer surfaces.
Another common contaminant in cooling towers are organic solids, such as leaves, grass clippings, pollen, algae, and bacteria. As with inorganic solids, organic solids tend to collect in basins, nozzles, and heat-transfer surfaces. But unlike inorganic solids, organic solids can pose a health risk to personnel.
Managers have several options for limiting the impact of contamination on cooling-tower performance. Water-treatment programs can help keep the contaminants suspended in the water, limiting their ability to form scale. Programs also can help minimize the growth of organic contaminants.
Even with a well-designed water treatment program, the quantity of solids in a cooling tower's circulating water tends to increase, so most tower manufacturers recommend a blowdown system that bleeds off a portion of the circulating water and replaces it with fresh circulating water. Technicians need to set the concentration of solids in the circulating water, as well as the rate at which water is replaced, in order to keep the tower operating within the manufacturer's guidelines for suspended solids.
To limit the accumulation of living organisms, manufacturers use two methods of water treatment — biocides in circulating water and exposing the water to ultraviolet (UV) light. Biocide programs must be designed for the specific environment in which the tower operates and be regularly monitored to be effective.
UV systems use chambers installed that expose the circulating water to a moderate level of UV light. The light is intensive enough to disrupt the DNA material within most organisms, either killing them or preventing them from reproducing.
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