The True Cost Of HVAC Scale

What can you, as the facility maintenance manager, do about limescale? Limescale and other water formed deposits can cause major loss of efficiency, increased operating costs, and minimize the life expectancy of capital equipment. But first, as a Facility Manager, how can you tell if your HVAC system is suffering from limescale build-up?

Signs of Increased Cost from Scale Buildup

Some of the symptoms will be gradual because limescale deposits build up over time. But small changes in equipment efficiencies can be a sign of limescale growth. Here are some additional signs that show you need to tackle your limescale problem:

  1. Rising operational costs (including tube or pump failures or the chiller shutting down due to high head pressure)
  2. Increased equipment downtime
  3. Progressively growing heating and cooling energy costs
  4. Poor equipment (boiler, chiller, heat exchanger, or tower) performance, including high head pressures or pump reading more elevated than usual

Rising operational costs

If your HVAC gas or electric bill is rising with no change in facility operational hours, there’s a good chance you’ve got limescale problems. Scale deposits can lead to significant increases in energy costs by reducing the heat transfer surface on both cooling (chiller) and heating (boiler) systems. Consequently, more energy is required to achieve the same level of heating or cooling when limescale fouling is impeding the energy coefficients. Also, the reduction in pipe diameter means your pumps work harder to move the same amount of fluid. This not only increases electricity costs but may lead to premature pump failure. Increased fuel costs mean increased building operating and maintenance costs, which affect the profitability of your business.

Some key findings on the costs of scale are:

  • Energy consumption is increased up to 11% for just 1/16-inch of scale, according to the American Society of Plumbing Engineers
  • Equipment failure rates increase due to scale
  • Scale often necessitates the use of chemicals to counter hard water use. Detergent usage increases by 2-4% percent per 1,000 gallons of water.

Increased equipment downtime

When left to build up inside HVAC components, scale deposits will eventually require removal for the equipment to function. Depending on the amount of build-up, the equipment may experience downtime for days or weeks. This downtime quickly cuts into the operational capability of a building, and if all HVAC systems serving a building are down, the building may have to cease operation entirely until the problem is fixed.

Preventing equipment downtime is one of the most significant concerns of facility managers, yet some may not realize that they need to practice correct preventative maintenance plans on their systems to prevent downtime. Naturally, all equipment will experience some sort of downtime for maintenance, but when equipment downtime sharply increases for cleaning, it may be evidence of a larger scale build-up problem.

Progressively increasing heating and cooling energy costs

Progressively increasing heating and cooling costs can be a reliable indicator of scale build-up inside HVAC components affecting the performance and efficiency of HVAC systems. This is especially true when heating and cooling costs increase despite a relatively stable period of climate and building usage.

Facility managers are certainly in tune with the energy costs that a building accrues. Energy costs are often one of the most significant operations and maintenance budget items that a facility manager is concerned about. If patterns of rising heating and cooling costs show a decline inefficiency, it may be time to clean the system entirely of scale build-up.

Poor equipment performance

Poor equipment performance – like on boilers, chillers, heat exchangers or cooling towers – is often first noticed by monitoring the key performance indicators of your systems. Things like the pump and head pressures should be monitored daily to identify baselines. This way, any disparency can quickly indicate scale issues.

Scale build-up inside the boiler, chiller, heat exchanger or cooling tower may be causing the lack of performance out of the system. Poor equipment performance will not only deliver inadequate heating or cooling results but also end up costing many multiples of the maintenances costs for replacement.

Preventing Scale Build Up

There are different methods for removing limescale build-up. These methods generally fall into two categories chemical and mechanical.

A combination of water treatment programs along with chemical or mechanical descaling is necessary to keep scale in check.

Chemical descalers are fluids which react with the calcium carbonate, sulfate or silica build-up to break it down and flush it out of the system.

Mechanical include using rotary tube cleaning or projectile-based systems to remove scale deposits mechanically. They work to remove the mineral deposits plaguing the tubes of HVAC chillers, fire or water tube boilers, heat exchanger tubes/coils and condenser tubes.

To slow the scale accumulation, water treatment solutions are often employed. Depending on the chemistry of your water source, a water treatment company will come up with the right treatment solution for your boiler or cooling tower. Regular tests and checks are essential to ensure the water is receiving the correct dosage of treatment chemicals. However, no chemical treatment will prevent scale deposits entirely, and so vigilant monitoring of system performance is required.

Next Steps:

If you haven’t been taking preventive action against HVAC limescale, today is an excellent time to start. It is never too late to begin, and you may be amazed by the results you will achieve. While there are many different options on the market today, choosing the right solution for your system is essential.

Get started by maintaining a daily logbook of your system parameters like head pressures, pump pressures, etc. The set up an annual or biannual maintenance cleaning program. This will help you get a handle on your scale problem. Next, get guidance from a reputable descaler manufacturer so you can make the right choices for addressing scale in your facility. With their expertise and products, soon your facility will realize lower running costs and a more efficient HVAC system.

Mechanical vs. Chemical Scale Removal: What Is Best For My Facility’s HVAC Equipment?

Scale or limescale is caused by mineral deposits in water becoming adhered to pipes, pumps and other hydronic system components. This adhesion is a natural occurrence when water is heated or cooled. Even the best-treated water contains scale deposits, however raw water deposits, including those from well and other underground sources, lakes, and ponds can contain significant levels of minerals, also known as “hard water”. In fact, over 80% of the continental USA has moderate to hard water.  Scale build-up that is caused by hard water can have numerous adverse effects on the systems and components that come in contact with the water. It is important for owners, operators, and facility managers to not only pay attention to excessive scale build-up but to also have a response and maintenance plan for removing the scale.

The first general approach to maintaining scale build-up is the use of mechanical tools and practices to remove scale build-up. There are multiple techniques and practices that fall under mechanical scale removal. Primarily, mechanical scale removal involves removal utilizing machines or machinery to physically remove the scale build-up from system components. For chillers, boilers and other heat exchange equipment, Goodway offers numerous excellent products that mechanically remove scale buildup from machine and system components. The RAM-4 Chiller Tube Cleaner is one of many varying capacity tube cleaners that, when paired with an appropriate brush, effectively cleans tough scale deposits in chillers, condensers, evaporators, absorption machines, and other heat exchangers.

When mechanical tools are not enough to rid scale, a chemical scale remover can be a great tool to safely, efficiently and effectively remove scale. Chemical scale removal is a generally more passive approach to system and component maintenance, where a chemical solution is flushed through the interior piping and components of a system and reacts with mineral scale build-up to remove and cleanse the system.

Chemical scale removal can be conducted in a number of ways but is most effective when the chemical is pumped through the interior piping and connections of a system. One such system that is effective on larger industrial HVAC and process machinery is the GDS-100-BV is Scale Removal System. When paired with ScaleBreak®, Goodway’s advanced descaling solution, the system quickly and effectively removes the scale leaving system operating at optimal efficiency. In fact, in many instances systems will operate at an efficiency higher than when first installed. Read how in this case study.

Plant maintenance managers need to understand both mechanical and chemical descaling options and how they apply to the equipment in their plant. Deciding between either method can be difficult, but there are a few key factors that managers can focus on to make their choice. These deciding factors for managers include upfront cost and lifecycle cost, effective fit for their intended use, the amount of money saved in operating and the extension of the usable lifetime of the serviced equipment, and any regulatory guidelines pertaining to the equipment needed to be maintained.

Goodway offers two excellent features on its website to assist managers with deciding which method of descaling equipment to purchase and utilize. Managers who are considering implementing a new maintenance plan or changing their current one should consult with the experts at Goodway and utilize the tools they have for making these difficult decisions.

The first feature on their site is their cost calculator. This cost calculator can break down the cost data for numerous types of equipment to include boiler, chiller, and cooling tower descaling equipment. Utilizing this calculator provides an excellent insight into the potential savings and best-fit equipment for different types of industrial equipment. The second decision-making tool that Goodway offers is their buyer guide, which provides key information and articles about descaling technologies, with further information on key factors to consider when choosing maintenance equipment.

 

Next Steps:

Watch our webinar on Scale: Why You Have It, What It Does and How to Descale Safely and Effectively.

Watch our webinar on Industrial Descaling: Challenges and Benefits.

See Instructions for Cleaning Brazed Plate & Gasketed Heat Exchangers with ScaleBreak.

See Goodway ScaleBreak® featured in Canadian Facility Management & Design.

Read up on Goodway Descaling Solutions For MULTISTACK® Chillers

Listen to this Podcast: Descaling Large Equipment brought to you from HVAC SCHOOL.

New Years Resolution: Preventative Maintenance of HVAC System Servicing Data Centers

Data centers represent a unique challenge to building managers. The stacks of servers require large amounts of energy to constantly run, while also emanating large amounts of heat into the room. The challenge is keeping energy costs low in a building while running a high energy-consuming, heat-producing data center at peak performance. As a building manager of a large data center, it is inevitable that the energy costs for cooling the building are likely the largest out of pocket cost each month. Despite the high cost of cooling, many building managers don’t focus enough on conducting proper planned maintenance of their HVAC systems. In order to save a significant amount in monthly energy expenses and long-term equipment bills, building managers should make a business-focused new year’s resolution to create or revive their planned maintenance schedule for HVAC.

According to the American Society of Heating, Refrigerating, and Air Conditioning (ASHRAE) the standard data center requires room conditions to be between 18 and 27 degrees Celsius (64 to 81 degrees Fahrenheit), with a dew point between -9 and 15 degrees Celsius, and relative humidity of 60 percent. The climate, heat output, building construction and makeup of the data center are just some of the numerous variables that make maintaining a room within those conditions both difficult and costly. The heat output of a data center is proportional to the combined amount of computing output and data storage capabilities of the center and likewise, the interior climate conditions inside a data center affect the efficiency of data transfer and server operation. When the HVAC system servicing a data center struggles to maintain internal climate conditions it is at the detriment of both the performance of the servers inside the center as well as the energy consumption of the building.

Maintaining an efficient and healthy HVAC system performance is one of the best approaches to counteracting potentially expensive data center costs. This level of system maintenance can be difficult depending on the demand put on the HVAC system. The interior climate demands in a data center are stringent and they require year-round HVAC performance, but they are also consistent. Unlike human-occupied spaces in a building that can have varying cooling demands, the heat output of a data center is relatively constant. The consistency of the heating load inside a data center provides a unique opportunity for building managers and plant owners to optimize their system to fit the needs of the data center while requiring the least amount of energy to run.

Planned maintenance of the HVAC system serving a data center is a crucial aspect of building management. Periodically scheduled cleanings of system components pay significant dividends in energy savings for an HVAC system. Chillers, coils and other components become clogged with material over time, reducing efficiency and drastically increasing costs.

A hydronic HVAC system or large chilled water system with a significant buildup of limescale and other water formed deposits will have to work significantly harder to maintain the room conditions of a data center. Scale deposits attach to the chiller tube walls, cooler tower piping, and other water-filled components of Hydronic and chilled water systems and reduce the heat exchange properties of the system, as well as the cross-sectional area available for fluids to flow through. This ultimately requires more energy for heat transfer and more power to propel the fluid through the system. Even a small-scale buildup inside pipes can require significantly more energy to cool a space. Additionally, for large HVAC spaces with constant use, a buildup of limescale can degrade the same components of and hydronic and chilled water HVAC systems, drastically reducing their effectiveness and decreasing their usable life.  Large data centers require the greatest cooling effort, and degradations will cause losses in the tens of thousands of dollars. Building managers can calculate their true cost of HVAC scale by using one of the descaling calculators at goodway.com/resources/calculators.

For systems where scale is not the issue, like Packaged HVAC system or RTU’s, scheduling the cleaning of coils is essential to maintain optimal temperatures. Wasted energy can cost between $1,000 and $3,700 per unit. Dirty coils can diminish heat transfer and increase operating temperatures and pressures. The importance to wash and flush both sides of the coils can be the difference between a data center overheating and shutting down or maintaining proper temperature and continuous power. Solutions, like the ones from Goodway, are specifically designed to clean coils. Just as cleaning the coils of such units the maintenance of cleaning the condensate drainage is consequential. Clogged condensate drain lines prevent water and other liquids from effectively moving out of the unit which can in time cause damage to the unit and surrounding area.

A comprehensive preventative maintenance plan is the single greatest method to minimize efficiency losses throughout the year. If building managers don’t already have a plan in place to maintain the efficiency and effectiveness of the HVAC system cooling their data center, they should implement one immediately. Maintenance plans can easily be synchronized with the calendar so that starting with the new year each maintenance plan becomes a new year’s resolution for HVAC efficiency. Setting a new year’s resolution is an effective way of making a permanent change for the future, and for a data center, a permanent change to regularly scheduled maintenance can produce savings throughout the life of the system. For specific problems such as system descaling, there are simple solutions such as Goodway’s ScaleBreak Liquid Descaler. Goodway’s line of ScaleBreak products safely dissolve mineral deposits inside your system components quickly and safely. The ScaleBreak Liquid Descaler is a low cost and effective method for achieving your new year’s resolution to carry out system maintenance.

Next Steps

Check out more information on these products at goodway.com/accessories/descaling-chemicals-accessories.

Pollution Control in Boilers

In recent years (data available to 2017), the United States saw significant improvements in air quality across the entire country. All of the major pollutants decreased in concentration over the study period including sulfur dioxide (SO2) down 79%, nitrogen dioxide (NOx) down 35%, and PM2.5 particles down 41%. The United States achieved these reductions through new environmental legislation, enforcement of existing laws like the Clean Air Act, and the advancement of pollution control technologies all while the nation’s economy grew and industrial capacity expanded.

As identified in an Environmental Protection Agency (EPA) report, a major source of air pollution is the burning of fossil fuels in industrial factories or boilers for power generation. The EPA warns that residuals from burning coal (coal ash) are “one of the largest types of industrial waste generated in the United States.” Burning coal is an inherently dirty process and federal limits restrict the concentrations of SO2, NOx, and PM2.5 discharged to the atmosphere. Modern boiler design and pollution reduction technologies are available so that plants can provide heat or electrical power at reasonable costs while still being compliant with environmental regulations.

Pollution control in coal-fired boilers can occur at all stages of the combustion process: pre-combustion, during combustion, and post-combustion.

Pre-Combustion

The selection of fuel to burn in the boiler is the first opportunity to reduce flue gas contaminants. For example, natural gas burns cleaner than fuel oil, medical waste, or biomass and produces the least amount of pollutants in its flue gas. Natural gas is considered a low-nitrogen fuel and yields very little NOx as a by-product of combustion. Also, as the EPA notes in its technical bulletin on controlling NOx that “natural gas is desulfurized before it is sent in a pipeline. Therefore, natural gas has almost no sulfur, essentially no impurities, and no ash.”

During combustion

The moment fuel and air ignite presents an opportunity to fine-tune the stoichiometry of the combustion process and the by-products of that reaction. With flue gas recirculation (FGR) a portion of the flue gas is sent back to the combustion chamber diluting the oxygen level of the combustion air, reducing the core flame temperature. The reduced temperature lowers the NOx level in the flue gases to below 20%. Cleaver-Brooks describes FGR as “the most effective and popular low NOx technology for firetube and watertube boilers. “

A fluidized bed recirculation (FBR) boiler burns crushed coal, wood or other low-grade fuels sitting on a sand bed within the boiler fireside. Combustion air is blown up through the bottom of the sand bed and mixes with the fuel on top of the sand where combustion occurs. This boiler design results in a fast mix of air and fuel and encourages rapid heat transfer. The burning environment gives a cleaner burn with reduced quantities of NOx and SO2 in the flue gases. SO2 emissions can be reduced further by introducing pulverized limestone into the combustion chamber. Sulfur in the flue gasses reacts with the limestone to form gypsum that, when separated from the fly ash, can be used to make other saleable products.

Post-Combustion

Coal ash leaving the combustion chamber can be captured and particulate pollutants removed before being released to the atmosphere.

One method for capturing fine particles like PM2.5 is to pass boiler flue gases through an electrostatic precipitator (ESP). With an ESP the flue gas flows across high-voltage wires that electrically charge fine particles suspended in the gas. The charged particles are attracted to a collection electrode, such as a series of metal pipes or plates, and accumulate on the electrode surface. ESP’s remove more than 95% of PM2.5 particles from coal flue gas and more complex ESP systems have removal efficiencies approaching 99%. To maintain such high levels, the collection electrodes should be cleaned per the manufacturer’s recommendations to minimize the thickness of fly ash buildup on the surface.

Cyclonic or cyclone fly ash separators (not to be confused with a cyclone furnace) are another method to remove fine particles from coal boiler flue gas. A cyclone separator works by blowing flue gasses against the interior wall of a cylindrical vessel. The gas enters the vessel near the top and circulates inside like a tornado. The centrifugal forces of the rotating flue gas push the fine particles to the outside of the “tornado.” The particles hit the interior surface and fall to the bottom to be collected while clean flue gas exits the vessel at the top. Although the efficiency of a cyclone separator may reach 90%, they are rarely used alone to meet EPA standards for particulate discharge. Most cyclone separators are used in conjunction with other technology like an FBR boiler to achieve the desired particulate concentrations. The clean flue gas can be analyzed to provide insight into the overall efficiency of the boiler and heat transfer processes inside.

The EPA’s 2018 report Our Clean Air summarizes things nicely, “The U.S. leads the world in having clean air and a strong economy due to implementation of the Clean Air Act and technological advancements from American innovators.” The power industry, pollution control manufacturers, and the EPA have a strong record of working together to create reliable electrical power while reducing atmospheric contaminants and improving the quality of the air we .

Power plant maintenance involves not only cleaning the boilers and chimneys, but servicing the heat exchangers, chillers, and condensers throughout the facility. In fuel storage areas, vacuums and power tools need to have explosion-proof motors to protect people from the dangers of coal and wood dust. Goodway offers a variety of power plant maintenance technologies that are safe and easy for technicians to use in any area of the plant.

Recording Available! Webinar: Industrial Boiler Cleaning

Goodway’s free webinar, “Industrial Boiler Cleaning” is available. The webinar host, Mark Roth, Goodway sales director, with guest Ray Field, Goodway’s director chemical technologies, walk through the basics of industrial boilers, the importance of cleaning and preventative maintenance, how to determine whether mechanical or chemical cleaning is the best solution for your facility, and the process for performing those cleaning options. There is also a question and answer session at the end of the webinar. Don’t miss this important webinar!

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