The Importance of a Closed-Loop Water System for Water Treatment
The water in your cooling or heating system dramatically affects performance. If you regularly monitor and treat the water in the cooling mechanism, it will reduce problems from water deposits. Monitoring the water quality of your cooling or heating system may not be a task you have the experience or equipment to do yourself, though. Don’t worry. You can get expert service for the water in your closed-loop cooling system. But before you request a quote, you should understand your system and why water treatment is such a vital part of maintaining it.
Overview of Closed-Loop Water System
Cooling or heating systems that use water can have one of two main types of systems for dissipating heat acquired by the liquid — closed loop or open loop. Each has its advantage when part of a cooling or heating system. The critical difference between these is the amount of exposure the water has to the air. More enclosed systems preserve water volume and quality.
Closed-Loop Water System Definition
Cooling and heating systems operate by using the temperature of water and refrigerant to transfer heat from a building to the outside. Open circuits deposit the cooling water into an open cooling tower that exposes the surface of the water to the air. In contrast, closed loops do not allow the water to receive direct air contact.
Open systems, while sometimes more economical to install, can have numerous problems with contaminants getting into the water of the cooling tower. Depending on the temperature, water can also evaporate or freeze from the cooling tower, requiring constant monitoring of the water level for the system’s operation. Due to the higher maintenance requirements of an open system, this type may have a higher price over time compared to a lower maintenance closed circuit system.
A closed circuit system keeps the water completely enclosed inside pipes. The process involves cooling the water inside the tubes in addition to a refrigerant. Cooling systems follow three necessary steps, which reverse in heating situations.
- Removing heat from the building: For cooling, the chilled water leaves the building and moves into the chiller. There, the water gives off heat to the circulating refrigerant. Once it has released its warmth, the now chilled water returns to the building where it contributes to process cooling or air cooling.
- Heating refrigerant inside the chiller: The refrigerant absorbs warmth very efficiently. When it picks up the heat, the separate line of cooling water between the chiller and tower absorbs the heat, transferring it to the tower.
- Releasing heat inside the tower: Inside a closed-loop cooling tower, the water on the tower side releases its heat, reverting to a cold state. This cooled water goes into the chiller to remove heat from the refrigerant to take the heat back out to the cooling tower.
Considerations for Closed-Loop Systems
Closed-loop systems have a reduced chance of contamination, but they are not maintenance free. Neglecting maintenance of a closed system promotes the growth of sludge and deposits. The most common problem with these systems is black magnetic iron oxide mud deposits. Over time, magnetic iron oxide particles bind together and collect on narrowed parts of the system. The most common places for this sludge include:
- Narrowed pipes
- Heat-transfer surfaces
- Cooling or heating coils
- Fan coils
Other problems can arise as the pH level of the water drops. Lowered pH could indicate bacterial growth or a system leak. Bacteria can lead to pinhole leaks in the pipes, which can affect both the water levels and chemistry. In addition to leaks, bacteria or mineral deposits can reduce the ability of the system to transfer heat by coating the surfaces of the parts. Regular care of your components through water testing and chemical maintenance prevents the corrosion of the interior components of the system. In the closed system, you will not see the results of the corrosion until the system shows signs of failure.
While open systems need monitoring of water levels and watching for particulate matter from the environment in the water, closed circuit systems need control of the water’s chemistry. Treating the water to prevent corrosion and freezing is part of maintaining these systems. Proper monitoring and care will ensure the system lasts a long time.
Despite the need for water testing, closed-loop systems do not lose water nor are they at risk of outside contamination. Open-loop systems will need much more frequent maintenance to prevent problems with the system and its water.
Industries That Use Closed-Loop Technology
Several sectors take advantage of more efficient closed circuit cooling systems. These industries need to invest in a system that will operate at its peak and require lower levels of maintenance throughout the year. Manufacturers, hospitals, industrial facilities and many other businesses and industries embrace the long-term efficiency and savings from closed-loop technology.
Closed-Loop Technology in Industrial Emergency Systems
Industries often need backup plans in the event of power losses. Some facilities require generators to keep the lights on, whereas others need an emergency cooling system to continue process and component cooling if the primary mechanism fails.
For instance, backup power generators used for commercial structures like hospitals or industry typically have closed-loop systems. The engines in these generators don’t require regular use, but they will need a cooling system when in operation. The increased efficiency of a closed circuit system ensures the generator has adequate cooling water and is always ready.
Nuclear facilities and other power plants use closed-loop water cooling for safety and non-safety components. Thanks to multiple cooling paths, the parts of a plant remain at a safe operating temperature. In nuclear facilities, redundant cooling mechanisms are critical to the safety of the plant. If the plant experiences a loss of its primary cooling, the closed-loop system allows for continued heat removal. Like backup generators in hospitals, closed-loop systems for nuclear power plants need always to be ready to engage fully in an emergency.
Industrial Applications of Closed-Loop Systems
Closed-loop systems have more uses than for emergencies. Many industries use these for process cooling. For instance, most food and beverage processing plants use open cooling towers for process chilling. However, some plants have chosen more energy- and water-efficient closed-loop systems for chilling. These facilities may use adiabatic systems, which apply pressure changes to alter temperatures. Other similar closed-loop systems are used near the beverage chillers for more efficient, more tightly controlled cooling for each separate process.
Aside from emergency use, closed circuit cooling systems also serve to cool down components at a power plant. Water systems help cool bearings, while other coolers chill lube, air compressors and oil. At a power plant, the moving parts can generate enormous amounts of heat. Using a cooling system reduces the heat wear on these components, and a closed-loop system cools while requiring less maintenance.
Benefits of a Closed-Loop System
Closed-loop systems offer several advantages compared to open systems. While closed-loop heating or cooling costs more initially, over time, that cost gets offset by the savings from better efficiency in all conditions. If you already have a closed-loop system, you’ll feel you made a quality investment. Should you need to replace your system, consider how a closed system can save you money over the years you use it.
1. Increases Efficiency
Closed-loop systems are more efficient than open systems. Since their design keeps the water enclosed inside the system, closed systems do not require additional water periodically to replace that lost from evaporation. Efficiency also increases in the winter when closed-loop systems can operate dry, which prevents freezing during the colder months.
Another aspect of these systems’ efficiency is in their reduced need for maintenance. While you should not cease all care for your system, closed circuit designs require fewer checks throughout the year. You will save money from lower maintenance costs and longer system operation.
Space efficiency is another way closed circuit systems are a better choice than their open counterparts. Without the need for a separate heat exchanger, as open systems require, closed-loop systems take up less space. By only using a single unit, closed circuit systems need much less of the precious space in your facility.
To further save energy, closed circuit cooling systems allow for pump speed changes. Lowering the pump speed can conserve energy when cooling needs decrease. The flexibility to adjust to cooling and energy needs makes closed-loop systems more energy efficient. However, this is not the only way closed systems can adapt to changes.
2. Ability to Adapt to Optimum Performance
The ability to adapt to cooling needs and outside temperatures makes closed circuit cooling systems a better option than open-loop systems. Closed-loop systems have four ways to adapt to temperature changes to improve performance and efficiency up to 50 percent savings compared to open systems.
- Dry operation: The system runs without cooling water, which protects the system from freezing and puts off the need for water testing and chemical treatment. This option works best in moderate weather by pairing exhaust fans with the heat exchanger. You don’t need cooling water for this option.
- Free operation: Free operation happens when you shut off the chiller. This option uses ambient temperatures to cool the process water rather than a chiller.
- Adiabatic cooling: Facilities that operate in hot conditions may need the pressure changes of adiabatic cooling. For hot climates, a pressurized system can help cool the water to even lower temperatures than traditional methods can achieve.
- Variable speeds: To maximize energy efficiency without sacrificing cooling power, closed systems use variable speeds. This allows for greater control over the cooling process. Compared to fans that only have on-off controls, variable fans cut energy use up to 25 percent.
Adaptability makes closed systems a better option for variable climates, but ultimately the upkeep of the system will determine its cost over time. Luckily, closed-loop systems have a design that reduces the need for regular, rigorous cleaning and maintenance.
3. Minimizes Exposure to Contaminants
Closed-loop systems do not have an opening to the air, but this does not mean the system has complete protection from foreign matter in the water. However, the water gets exposed to a minimal amount of pollutants. Reducing the contaminants and debris in the system extends the life of the entire system by lengthening the amount of time before components need replacements.
Thanks to the closed design, with well-treated and monitored water, the system can go weeks between chemical treatments. In a system without any leaks, as long as water monitoring and treatment occur regularly, this scheduling should suffice. However, if the system contains holes, chemical treatment of the water will not result in the balance needed. If you neglect the system too long, it can develop leaks, which makes it harder to maintain.
To prevent corrosion in carbon steel components, the water must maintain a high, or alkaline, pH. To keep the correct chemical balance, water treatment professionals have several options at their disposal:
- Polymer treatments: Once exclusively used for open cooling towers, now polymer treatments help maintain closed systems. These treatments disperse components in the water that may contribute to corrosion or scale. With a tightly closed system, polymer treatments do not affect the environment.
- Sodium nitrite: Sodium nitrite has a counterintuitive function. This chemical purposefully corrodes the entire system evenly, but with even corrosion, there are no uneven spots for additional wear. The downside to using sodium nitrite in a closed system comes from bacteria in the system. Certain bacteria consume sodium nitrite, which increases their population. High levels of bacteria can create films that contribute to corrosion.
- Sodium molybdate: Sodium molybdate inhibits oxidation. Unfortunately, the price of this compound varies wildly due to political unrest in areas associated with molybdate.
These substances are not the only options for maintaining a closed-loop system, but they are a sampling of the products maintenance professionals could use.
Contact Chardon Labs for Closed-Loop Water Treatment
Don’t neglect your closed-loop water system. It still needs water treatment, despite myths to the contrary. Regular treatment of the water and the system itself will ensure it continues to operate flawlessly for years. Without routine care, your water could cause corrosion or excessive mineral deposits on the parts of the closed-loop system. These conditions can quickly deteriorate your system without you knowing until efficiency drops to detectable levels.
To prevent serious harm from untreated water, you need frequent treatment of the system and its contents. The closed-loop system will need an expert to change the filters, conduct pH balance checks and perform maintenance checks. At Chardon Labs, we can help with these tasks and many others for your system. We have the water treatment professionals who know the right way to balance the water chemistry in your system. We won’t sell you chemicals. We provide you with a clean system via our expert maintenance. For more information about our water treatment and system maintenance, contact us today. We want to help you get a clean system that will last.