Challenges of Scale Buildup:

Scaling is a hard layer of mineral deposits precipitated from the cooling water and builds on the chiller surfaces. The precipitation of these mineral deposits is more prevalent at higher temperatures. Therefore, scale build-up usually occurs first on heat transfer tubes of chillers.

While some of the symptoms will be seen over time because scale deposits build up over time, small changes in equipment efficiencies can be the first sign of scale growth. Here are some efficiency problems that remind you to tackle your limescale problem:

In this process, heat is absorbed from the chilled water circulating through the evaporator. Then, the compressor pumps the refrigerant vapour to the condenser, thus increasing temperature and pressure. To complete the cycle, the refrigerant flows over the chilled water coils and absorbs more heat.

• Rise in operational costs (including tube or pump failures or the chiller shutting down due to high head pressure)
• Increased equipment downtime
• Increase in heating and cooling energy costs
• Loss in performance, including high head pressures or pump reading more elevated than usual

“By understanding how these issues affect your HVAC systems, and their associated cost drivers, you can make informed decisions on the proper scale and biological fouling control”. Shared Mr Tsur Ben David.

So let’s take a closer look into these signs:

A rise in operational costs

When your energy consumption is rising with no change in facility operational hours, there’s a good chance you’ve got scaling in your chillers. Scale deposits reduce the heat transfer surface on chiller systems, leading to significant increases in energy costs.

When scaling is impeding the energy coefficients, more energy is required to achieve the same level of heating or cooling. Also, the build-ups in condenser tubes mean your pumps work harder to move the same amount of fluid.

It 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.

Increase in equipment downtime

Without regular cleaning, scale deposits will eventually require complete removal for the equipment to function. And the equipment may be out of operation for days or weeks, depending on the volume of build-ups.

Unexpected downtimes van quickly cut into the operational capability of a building. If all HVAC systems serving a business are down, the business may have to shut down its operation entirely until the problem is fixed. That’s why preventing equipment downtime is one of the most significant concerns for facility managers.

All equipment 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. You need to realize that practising correct preventative maintenance plans on chillers can prevent downtime.

Loss in performance

The performance of HVAC systems depends on the efficiency of boilers, chillers, heat exchangers or cooling towers. That’s why any performance loss is first noticed by monitoring the key performance indicators of these systems.

Scale build-up inside the chiller or heat exchanger is the main cause behind the loss of performance. It not only leads to inadequate heating or cooling results but also ends up costing too much in maintenances costs and replacement. Inadequate performance and efficiency of HVAC systems can also increase the heating and cooling costs.

While there are different methods for controlling scale build-up, they generally fall into two categories – chemical and mechanical. However, both require regular checks and will not prevent scale deposits entirely. So vigilant monitoring of system performance is required.

Said Mr Tsur Ben David, “With CET Enviro’s ACCS, you can automatically clean heat exchanger tubes while the equipment remains in operation and full production. It’s an online method that infuses some slightly oversized elastomer balls periodically into the Condenser tubes and keeps the tubes free of fouling 24×7”.

“We have designed this system to suit the specific requirements of Water Cooled chillers, with R&D done in Israel and already have more than 1000 installations across the globe” said Mr David.