Generally, demineralized water is used for closed-loop cooling water makeup, but chemical treatments are required to prevent corrosion and, in some systems, freezing. Most commonly, the piping in a closed-loop system is carbon steel. Heat exchange surfaces, such as air chiller assemblies, may be copper or even aluminum.
Why choose a closed loop cooling water treatment system?
Using a cooling water treatment can reduce the heat wear on these components, and a closed loop system cools while requiring less maintenance. Closed loop systems offer several advantages compared to open systems.
What type of water is used in a closed loop system?
Generally, demineralized water is used for closed-loop cooling water makeup, but chemical treatments are required to prevent corrosion and, in some systems, freezing. Most commonly, the piping in a closed-loop system is carbon steel. Heat exchange surfaces, such as air chiller assemblies, may be copper or even aluminum.
What is a closed loop system in plumbing?
When hot or chilled water recirculates through a piping system with little to no makeup water it is known as a closed loop. Some of the concerns with closed loop systems are corrosion, scale, particulate and microbiological growth.
How do I choose the best chemical treatment for a closed loop?
Several chemical treatment methods have been developed for closed loop systems. The selection of one method over another is determined by the water quality, the type of antifreeze used, the system metallurgy, and any environmental or safety issues that must be considered.
How do you flush a closed loop heating system?
A much better way to flush a closed loop is to open a drain valve near the lowest point in the system and flush water at 1 to 2 gallons per minute. Be careful not to flush too fast; pressure make-up valves are designed to maintain pressure in the loop and may not pass more than 1 or 2 gallons per minute.
Why do you treat water in a closed heating loop?
Chilled water systems require treatment to prevent corrosion of the metals within the system. The most common metals are steel, copper, and copper alloys. If the copper is allowed to corrode, the copper ions in the water quickly plate out on the steel in the system, causing galvanic corrosion of the steel.
Do closed loop systems require maintenance?
Considerations for Closed Loop Systems Closed loop systems have a reduced chance of contamination, but they are not maintenance-free. Neglecting the 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.
Which chemical is commonly used as a corrosion inhibitor in closed loop systems?
Sodium NitriteSodium Nitrite based solutions are the most popular corrosion inhibitors in a closed loop system.
What is closed loop water treatment?
A closed-loop cooling system can exchange heat with the main cooling water system in conventional tube and shell heat exchangers or plate and frame heat exchangers. Chilled water systems (air chillers) exchange heat with the compressor, which in turn uses a cooling tower to throw heat back into the environment.
Which is better open-loop or closed loop geothermal?
Durability: The performance of an open loop system may degrade over time if water quality issues like silt, sediment or high mineral content are present or if the water supply diminishes for any reason. Closed loop geothermal ground loops can last 50+ years — even up to 100 years with little to no maintenance.
How do you know if you have a closed loop water system?
If you see a backflow prevention device (like a check valve or pressure-reducing valve) connected to your main water shutoff valve, then you have a closed plumbing system....Your water shutoff valve is usually located:On an outside wall.In a basement.In a utility room or closet.
What is an acceptable make up water reading on a closed loop hydronic system?
Water added to a closed hydronic system should not exceed more than 10% of the system volume per year and meter readings should be recorded, at least monthly, to ensure system losses are minimized and corrective actions shall be taken when needed.
What is closed loop liquid cooling?
Essentially, a closed loop is a pre built water cooling loop that you don't have to put together yourself, it comes pre made out of the box and is installed to a system by simply attaching the radiator/fans to the case and a CPU block usually via a specific bracket.
How is corrosion reduced in a closed cooling water system?
The three most reliable corrosion inhibitors for closed cooling water systems are chromate, molybdate, and nitrite materials. Generally, the chromate or molybdate types have proven to be superior treatments. For mixed metallurgy systems, the molybdate inhibitors provide the best corrosion protection.
What is a corrosion inhibitor used in water treatment?
Corrosion inhibitors are chemical products which, when added to water or to any other process fluid, slow down the rate of corrosion. They are normally classified as: anodic, cathodic, film-forming and oxygen-absorbing agents depending on their mode of action.
Is phosphate a corrosion inhibitor?
Phosphate is commonly used to minimize corrosion to potable water distribution systems, residential, commercial and industrial potable water piping, and reduce lead corrosion to comply with EPA standards.
What are 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: 1 Narrowed pipes 2 Heat-transfer surfaces 3 Cooling or heating coils 4 Fan coils
Which is more efficient, a closed loop or an open loop?
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.
How does a closed loop cooling tower work?
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.
Why use water cooling system?
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.
How does a cooling system work?
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.
Why do nuclear plants use closed loop cooling?
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 ...
How does water help a building?
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.
Why use water treatment for hot and cold closed loop systems?
Why Use Water Treatment For Hot & Cold Closed Loop Systems? Closed loops that are not properly treated can cause significant corrosion damage and can waste water and energy. These systems must be checked on a regular basis to confirm proper treatment level and system integrity.
What is a closed loop inhibitor?
Chilled water closed loop inhibitors must provide good protection for steel, copper, and any copper alloys that are in the system. Tempered water systems found in heat pump applications have the same treatment requirements and potential problems as both chilled and hot water systems, depending on whether the system is in the heating or cooling mode.
What happens when a hot water system leaks?
Hot water systems that are leaking bring in fresh water that contains oxygen, so oxygen pitting corrosion can quickly damage the system when it develops a leak. Appropriate treatment to deal with this oxygen must be applied until the leak can be eliminated. Chilled Water Systems.
What metals can be corroded by cold water?
The most common metals are steel, copper, and copper alloys. If the copper is allowed to corrode, the copper ions in the water quickly plate out on the steel in the system, causing galvanic corrosion of the steel. Chilled water closed loop inhibitors must provide good protection for steel, copper, and any copper alloys that are in the system.
Can glycol be treated with closed loop inhibitors?
Trying to treat uninhibited glycol with convention al closed loop inhibitors will NOT provide adequate protection from corrosion in these systems. The glycol must be maintained at the appropriate level, usually 25 to 30 percent of the fluid, to provide adequate protection from corrosion and freezing. Special glycol feeders must be used ...
When should a closed loop system be cleaned?
If the closed loop system is new, it should be chemically cleaned prior to the start of the treatment program. Chemical cleaning removes oil, mill scale, dirt, welding fluxes, and other contaminants that can interfere with the performance of the treatment program. Chemical cleaning is also recommended for older systems which suffer from corrosion.
What determines the selection of a closed loop system?
The selection of one method over another is determined by the water quality, the type of antifreeze used, the system metallurgy, and any environmental or safety issues that must be considered .
How much sodium nitrite is needed for a hot water system?
A 1,000 ppm residual of sodium nitrite is recommended in high temperature hot water systems. For those waters that are high in chlorides or sulfates, 1,500 ppm is required. A general recommendation for inhibitor levels is 800 to 1,200 ppm as sodium nitrite. Nitrite functions as a reducing agent in closed systems.
Is corrosion a problem in a closed system?
Corrosion damage in closed heating and cooling systems is a common problem . As an integral part of heating, ventilation, and air conditioning systems, they circulate hot water in the winter and cold water in the summer.
Can you use raw water to fill a closed well?
Typically, raw water as received from a municipality or private well is used to fill a closed system. However, this may not be the best alternative.
Is oxygenated water corrosive?
Although it is true that untreated, oxygenated demineralized water is very corrosive, particularly at hot water temperatures, corrosion inhibitors such as sodium nitrite passivate metal surfaces resulting in a final system water that is noncorrosive.
What is closed water cooling?
Closed systems are also widely used in air conditioning chilled water systems to transfer the refrigerant cooling to air washers, in which the air is chilled . In cold seasons, the same system can supply heat to air washers. Closed water cooling systems also provide a reliable method of industrial process temperature control.
What are the three most reliable corrosion inhibitors for closed cooling water systems?
The three most reliable corrosion inhibitors for closed cooling water systems are chromate, molybdate, and nitrite materials . Generally, the chromate or molybdate types have proven to be superior treatments.
What temperature does a corrosion curve drop off?
At up to 170°F (77°C), the curves are essentially parallel. Beyond 170°F (77°C), curve B drops off. This occurs because the lower solubility of oxygen with increasing temperatures in a freely vented system decreases the corrosion rate faster than the rise in temperature increases it.
How does a closed recirculating water system work?
In a closed system, water circulates in a closed cycle and is subjected to alternate cooling and heating without air contact. Heat, absorbed by the water in the closed system, is normally transferred by a water-to-water exchanger to the recirculating water of an open recirculating system, from which the heat is lost to atmosphere ( Figure 32-1 ).
What temperature does a closed cooling system need to be?
Closed cooling systems that are shut down periodically are subjected to water temperatures that may vary from ambient to 180°F (82°C) or higher.
What are the advantages of closed recirculating systems?
They provide better control of temperatures in heat-producing equipment, and their small makeup water requirements greatly simplify control of potential waterside problems.
Why is it important to use high quality water?
The use of high-quality water also minimizes the dangers of cracked cylinders, broken heads, fouled exchangers, and other mechanical failures. Closed systems are also less susceptible to biological fouling from slime and algae deposits than open systems.
