Chiller units — open loop or closed loop — naturally experience performance degradations over time. As noted by Facilities Net, chillers and companion condenser units are often the single biggest energy spend in an organization and despite predictive maintenance methods such as vibration analysis, infrared thermography and rotor bar testing, scale and foiling still occurs. Here’s a look at the impact of scale on your condenser system and the steps you can take to maximize efficiency.
Sources and Spending
To limit the impact of condenser fouling you need to identify the source. If you’re running an open loop system, the biggest problem comes from the water source itself — minerals and other particulate matter can quickly cause scale to build up if water isn’t properly treated before being transferred to the chiller. In closed loop systems, the cooling tower itself becomes the key source of contaminants, which in turn make their way into condensers and drive the growth of scale build-up.
As noted by Innovas even small amounts of scale in your system result in big impacts. For example, a 2000 ton chiller running 3000 hours a year with an energy efficiency rating of 0.65 kW/ton gives an energy cost of $0.09 kW/hr. With just 0.006 of scale, energy costs jump $14,000 per year. At 0.036 inches, extra costs skyrocket to $95,000 per year.
Saving the System
So how do you maximize chiller efficiency and ensure you’re not wasting money on fouled condensers? ACHR News and Facilities Net suggest a few straightforward methods, including:
- Increased Chill Water Temperature — Even increasing the chill water temperature a degree offers a 2 to 4 percent energy efficiency increase
- Treat Water Aggressively — ACHR recommends combining an aggressive biocide plan with scale and corrosion protection practices to limit scale production.
- Ensure a Leak-Free Unit — Leaks in condenser and chiller units introduce air into the system which significantly lowers efficiency and can also cause interior rust build-up. In high-pressure units, leaks can release hazardous gasses into the nearby atmosphere.
- Keep Daily Logs — Keeping track of day-to-day condenser performance allows you to conduct regular data comparison and ensure you’re meeting efficiency targets.
Despite best efforts, chances are you will need to deal with scale eventually. Best bet? Leverage a high-quality chemical descaling treatment in early spring or winter months when condensers and chillers aren’t on high-use cycles. Worth noting, however, is that even minor scale build-up always trumps existing descale plans since the energy loss simply isn’t worth waiting for regular maintenance. While this may mean an unexpected shutdown of chillers for several days and a commensurate drop in productivity, this cost is minimal compared with the exponential expense of fouled condenser systems.
Scale is a cooling tower’s worst enemy: Design an effective PM procedure and descale on demand to ensure maximum efficiency.
Subscribe to our Seasonal HVAC System Efficiency Podcast Series. This time of year our focus is on Boilers, Chillers and Cooling Towers.
We came. We saw. We introduced over 10,879 HVAC&R industry professionals to some of the most advanced tube cleaners, cooling tower cleaning systems and coil cleaners that Goodway has to offer in Latin America, at this year’s AHR Expo Mexico. Thanks to everyone who stopped by booth 912 to witness what Goodway has to offer for easier, faster and more effective HVAC maintenance cleaning.
Stay tuned for 2018 AHR Expo Mexico in Mexico City, and for more information on Goodway’s innovative maintenance solutions, clic aqui.
Boiler cleaning is something most companies don’t want to think about — if boilers are working within operational limits it’s often easier to keep up with smaller preventative maintenance (PM) tasks but put off a total chemical clean until performance starts to suffer. The problem? Once scale forms on boiler surfaces both fuel and efficiency losses quickly ramp up. Here’s a look at the cost of scale and the case for regular chemical cleaning.
What’s the real impact of scale on boiler efficiency? According to the Department of Energy (DoE), even “normal” scale at 1/32 inch thickness produced by low-pressure applications leads to a two percent fuel loss. In high pressure applications, the resulting iron plus silica deposits can result in fuel losses of up to seven percent. And while two percent may not sound like much, the EPA offers a helpful example: A firetube boiler using 450,000 MMBtu of fuel (at $8.00 per MMBtu) over 8000 hours per year with 1/32 inch of normal scale means a yearly operating cost spike of over $70,000.
As noted by research from NC State University, the reduced heat conductivity of scale leads to big problems in agriculture applications: If left untreated, ½ inch thick scale can lead to 70 percent increased fuel usage and significantly reduce overall boiler efficiency. Simply put? Even minimal scaling is a major problem.
Chemical cleanings aren’t cheap — and require you to shut down boiler operations for at least a day. So how do you know when it’s worth investing the time and money and when you can afford to wait?
As noted by ACHR News it’s a good idea to conduct regular visual inspections of boiler tubes to check for scale build-up. Regular monitoring of flue gas temperature can also indicate a problem — if the temperature rises when boiler load and excess air are held constant, scale is the likely culprit. Other reasons to consider a chemical clean include one or more system failures due to corrosion, or if you replace a significant amount (more than 10 percent) of your boiler tubing. According to Hartford Steam Boiler, evidence-based assessments are always the best way to determine chemical cleaning needs; while time-based cleanings have the benefit of simplicity and regularity they can’t take into account the myriad factors — such as water chemistry, frequency of startup, shutoff and blowdown — which contribute to scale formation.
Once you’ve identified scale, the next step is selecting a chemical solution and deploying the product. Best bet here? Draft and follow a solid set of best practices to ensure your chemical clean fully penetrates and dissolves scale before you flush and re-ignite boiler systems. Given the cost and time investment associated with chemical descaling, it’s worth doing right the first time.
Bottom line? Scale is expensive and ruins boiler efficiency. Rely on evidence-based methods to detect build-up and immediately deploy a full chemical descale if your boiler shows any signs of scale.
With the FDA tightening food label regulations and the risk of added allergens prompting regular product recalls, it’s worth taking a look at the future of food — what’s currently in development, what’s just around the corner and what can companies expect to see down the line?
Country of Origin
Last year Australian authorities were forced to recall a particular brand of bagged and frozen berries — which originated in Chile and China — after a Hepatitis A infection of four adults was linked to the product. According to ABC, the country is now rolling out new legislation which requires companies to mark the “country of origin” on virtually all food products. Products made in Australia will carry a “kangaroo” logo and also specify which ingredients were sourced locally, which were purchased elsewhere and which items were simply “assembled” in the country. It’s a big step for consumers and producers, who are now on the hook to design and implement entirely new labels within two years.
Stateside, the country is rolling out legislation which requires all foods containing genetically-modified organisms (GMOs) to be labelled as such. As noted by PBS, Congress recently approved the new bill; the Agriculture Department has two years to write specific rules detailing exactly what these labels need to contain. At minimum President Barack Obama says that most packages will need to carry a label with text, symbols or electronic codes which indicate the presence of GMOs. While the scientific community and the FDA agree that products which contain genetically modified organisms are safe to eat, consumers want “more information” about the origin and composition of specific ingredients.
The New Expectation?
With consumers and government agencies now demanding that food retailers and manufacturers both track and detail the country of origin and specific ingredient composition of their products, it’s not hard to imagine next steps. In the same way consumers worry about contamination from potential allergens or GMOs, for example, they could just as easily have concerns about specific food manufacturing techniques — leading to legislation which compels producers to provide details about the machinery which processes and packages certain food.
Hand-in-hand with type of potential oversight comes increased scrutiny of cleaning techniques and scheduling; violations could see companies fined or out of business until issues are addressed. Getting ahead of the game here starts with record-keeping — by keeping accurate and detailed reports about when specific machines were cleaned, how this task was carried out and if any issues were detected, processors can help future-proof their production lines. According to Evan Reyes, Goodway Technologies product specialist for the food industry, “complete, accurate, thoroughly documented SSOPs and Master Sanitation Schedules are essential for the modern food processor,” especially since under new FSMA legislation effective documentation is mandated by law and SSOPs can be requested by the FDA during any inspection. Despite the use of SSOPs, proper ingredient labelling and the use of color-coded production tools, cross-contamination of GMOs or non-origin-country ingredients may still occur. Here, your best bets are highly adaptable and thorough cleaning systems, such as HEPA filtered vacuums which capture food particles down to the micron level, helping to quickly eliminate any extraneous ingredients which have made their way into your food-prep or processing environment.
Emerging food legislation is focused on the combination of origin specificity and easy consumer access to ingredient information. Moving forward, companies should expect a greater focus on process mechanics and record-keeping — the right prep now can help buffer businesses against demands of new food product policies.
ASHRAE Standard 188-2015 has everyone in the industry raising the subject on the most effective way to manage Legionella, including more comprehensive cooling tower maintenance strategies and how these can promote better IAQ. This September 12th – 14th, at the upcoming ASHRAE IAQ Conference, Ray Field, Director of Goodway Liquid Solutions, will discuss a five-step preventative maintenance program that answers some of the most common cooling tower questions facility managers and contractors have when combating Legionella and improving IAQ for more efficient HVAC systems.
– Ray Field, Director of Liquid Solutions
Studies have shown that 40 – 60 percent of cooling towers test positive for Legionella. Early detection and action can prevent rapid growth and spreading, but deferred Legionella maintenance can only reduce the performance of system equipment even more – causing higher energy expenses, irreparable equipment breakdowns, or costly replacements.
Owners of these human occupied buildings and those involved in the design, construction, installation, commissioning, operation, maintenance and service of centralized water building systems are held responsible for outbreaks and are currently holding the lives of its pedestrians in their hands. Don’t drop the ball on proper cooling tower cleaning. Learn what can be done to control the growth of Legionella in HVAC systems and prevent risking the health of others in the community.
For more information on the conference and how to register, click here.