What is food grade glycol?
The ROTOFROST 100 is made of food grade Propylene Glycol and contains corrosion inhibitors which are food grade and nontoxic. As such it is mixture of food grade chemicals and safe and non-toxic. It is meant to use for accidental or leakage use, not as direct food. However, its raw material is food grade additive and is safe for use in food as per prescribed limits
Does the Inhibited Glycol protect the metal in my systems?
ROTO range of inhibited glycols have combination of synergistic chemicals protecting the metals in your system, which uninhibited glycol lacks. Our ROTO range of inhibited Glycols will not affect plastic but will affect aluminum (above about 150°F) and galvanized steel. The zinc in the galvanizing will react with our inhibitors and cause loss of the zinc coating leading to localized corrosion. For Aluminum protection at higher temperatures we have different grade for which you can contact our sales team.
Ethylene Glycol versus Propylene Glycol
Water is probably the most efficient heat-transfer fluid known. If it did not freeze, water would be the ideal heat-transfer fluid for cooling applications. When freeze conditions exist (<35 F), Ethylene glycol and Propylene glycol can be added to water to provide freeze protection and burst protection. Both glycols have lower heat-transfer efficiencies than water and are denser, resulting in higher volumetric flowrates or heat-exchange areas required to maintain the same temperature levels.
Higher flowrates lead to higher pressure drops, energy consumption, and equipment wear. As a result, it is important to accurately determine the minimal concentration of glycol needed to do the job in order to maintain system efficiency. Between the two, ethylene glycol (C2H6O2) is a better heat transfer fluid than propylene glycol (C3H8O2). Propylene glycol is less toxic and is considered when toxicity is a concern.
Why are Glycols used?
Glycol is a water-miscible coolant that is frequently used in heat transfer and cooling applications. It provides better heat transfer parameters than water and can be mixed with water to provide a variety of heat transfer characteristics. Glycol comes in two varieties: ethylene glycol and propylene glycol.
To understand the purpose of glycol, you must first understand how a chiller works. A chiller consists of two key parts: a refrigeration unit which uses electrical energy to produce a cold fluid, and heat transfer coils which move cold fluid from the refrigeration unit to the target area and hot fluid from the target area to the refrigeration unit. Typically, the target area is the inside of a freezer or some other object that you want to cool. The refrigeration unit often consists of a compressor with some compressible heat transfer fluid such as freon.
Every chiller has an operating temperature range. This temperature range is determined by several variables, the most important of which are the boiling point and freezing point of the heat transfer fluid. Glycol is prized as a heat transfer fluid because it can operate at a wide range of temperatures and can be mixed with water. The boiling and freezing points of glycol mixtures are a function of the relative amounts of glycol and water in the mixture.
Pure water freezes at 0 degrees Celsius (32 F) and pure ethylene glycol freezes at -12.9 C (8.9 F). In between, freezing points are non-linear. For instance, a solution of 10% ethylene glycol freezes at -3.4 C (25.9 F), 30% ethylene glycol freezes at -13.7 C (7.3 F) and 60% ethylene glycol freezes at -52.8 C (-63 F). The freezing point of a 60/40 ethylene glycol/water mixture is much lower than that of either pure ethylene glycol or pure water. Mixtures of propylene glycol with water follow a similar pattern, with a 60/40 mixture of propylene glycol with water having a freezing point of -48 C (-55 F).
The low freezing points of glycol mixtures make them ideal for cooling items below the freezing point of water. Thus, glycol/water mixtures are often used to cool freezers and similar environments.
Glycol is useful even when you do not want to cool an item below the freezing temperature of water. The rate of heat transfer is proportional to the difference between the temperature of your coolant and the temperature of the item being cooled. The heat capacity of the coolant, which is a chemical characteristic of the material, is important as well, but we will put it aside for the moment. A 60/40 ethylene glycol/water mixture cooled to -40 C can chill an item at 20 C much more quickly and efficiently than pure water at 10 C. Although ethylene glycol has a lower heat capacity than water (each kilogram of glycol is easier to heat than a kilogram of water), the larger temperature difference allows a glycol mixture to carry heat away much more quickly than pure water.
The low temperatures associated with glycol mixtures make them useful for applications where a chiller must carry a large amount of heat must away quickly. Heat is a byproduct of many chemical reactions; glycol’s ability to carry heat away quickly makes it useful for maintaining the temperatures of chemical reactions.
What is the difference between Freeze and Burst Protection?
Water volume expands by 9% when frozen. Glycols depress water’s freezing point providing protection to temperatures as low as -70 F to -100 F. Freeze protection prevents ice crystal formation at the lowest temperature expected in the coolant circuit, thus actually making this glycol-water combination work as refrigerant media. This type of protection is necessary for year-round pumping.
Burst protection requires less glycol and allows some freezing to turn the coolant into a slush that is not easily pumped but will not cause the pipe to burst. This method is used in closed circuits that are not operated in cold weather. The glycol content needed for this protection is lower than
What is the quality of water I should use for mixing with glycols?
Although you should never mix glycol types there is something that should always be added: water. Glycol must be mixed with water to function properly and get desired freezing point. However, we also offer pre diluted variants for ready to use. The type and amount of water to use are key factors to consider.
Each glycol chiller comes with its own set of manufacturer recommendations for the best type of water to use for that system. We recommend deionized water as first preference for dilution with our products, however reverse-osmosis water, can be used.
High quality water will help maintain system efficiency and prolong glycol fluid life.
How much water should I use to dilute with inhibited Glycol?
Calculating the proper ratio of glycol to water in your chilling system depends on the coldest temperature that the glycol solution will reach during operation. If a chilling system is used indoors where there is no chance of freezing, the amount of glycol needed would besignificantly less than required by a glycol chiller used outdoors where temperatures are prone to drop below freezing.
Also, if an application requires a very low temperature to operate it should use a glycol mixture similar to that of an outdoor system.
Using the proper ratio of glycol and water in your chilling system is very important. Adding too much to your chiller system will cause it to become inefficient. However, not enough glycol could cause the system to freeze up, potentially bursting pipes or even rupturing the chiller evaporator.
Automatic makeup water systems should be avoided to prevent undetected dilution or loss of glycol.
Please contact us for our freezing point / burst point chart of our products.
Determining the Percentage Glycol to Be Maintained:
Let us assume that if the chiller system is at +27 °F glycol, the freezing point of the solution only needs to be below +27 °F. But you must keep in mind the temperature of the refrigerant will be 10 – 15 °F below the temperature of the glycol solution. So, if you’re operating with a +27 glycol Temperature, your refrigerant temperature is about +12 to +17 °F. The recommended freezing level of your glycol/water solution should be 20-25 °F. below your chiller system set point.
Chiller Setpoint: +27°F
Glycol Freeze Level: + 7°F – +2°F
Ensure your glycol burst protection level is significantly lower than your lowest anticipated environmental temperature.
How much glycol would you need for the system?
First, you will need to determine the systems total water holding volume.
1) Figure out the estimated capacity of your systems piping.
2) Add to this, the volume held by your tank jackets
3) Finally, add the capacity of your chiller system reservoir to get you total system volume.
Find the volume needed by getting the % needed as above to
You can use our online Glycol calculator for that
Also, when you are tanking up with new glycol with old glycol in tank, it is suggested that you evaluate glycol content in tank currently and then minus the same from new calculations. However please evaluate the quality of Glycol in tank
Why do I need to replace my glycol?
The replacement cycle for glycol depends on the environment in which it is used. If the glycol is exposed to high temperatures (>250°F) or has a significant amount of contamination, the cycle will be far more frequent. It’s likely that a truly closed loop with no makeup can go for years without changing glycol. However, glycol will break down to glycolic acid over time and will require changing. Even the glycol in your automobile requires periodic changing. Additionally, the pH of the mixture may become acidic which is another strong indication of glycol breakdown.
Why is my glycol turning brown?
All glycols produce acids in the presence of air (oxidants). The acids can reduce pH and cause corrosion. When the system pH drops below 7, rust will form on any ferrous metal, and nonferrous metals start to corrode. The iron would react to give iron organic salts, which can be reddish to brownish in color depending on oxygen level. For HVAC applications, glycols are formulated with passivating and buffering corrosion inhibitors to counteract acids formed by the oxidation of glycols.This can be prevented by using ROTO range of glycols, however the pH has to be monitored and maintained regularly using ROTOHIB.
How long would my glycol last?
Glycols can typically be expected to last 3 years or longer, provided corrosion inhibitor strength is maintained.
We offer our corrosion inhibitors supplements in range ROTOHIB whichcan be added, as per need. It would require proper maintenance.
How do I know my glycol is going bad?
Glycol fluid pH can be a good barometer for the condition of the glycol. pH is primarily barometer; it should be maintained around in the range of 9.0 to 9.5 using ROTOHIB. A pH reading below 8.0 indicates that a significant portion of the inhibitor has been depleted and that more inhibitor needs to be added. When the pH falls below 7.0, we would recommend replacing the fluid. A pH value of less than 7.0 indicates that oxidation of the glycol has occurred. If the color is changed it is recommended to replace glycol. The system should then be drained and flushed before severe damage occurs. Should the system require cleansing after removing old or damaged antifreeze, flush the system with a heated 1% to 2% solution of trisodium phosphate for two to four hours then drain and rinse thoroughly.
Can I use automotive grade glycol?
Do not use automotive-type glycols. These glycols are formulated with silicates which tend to gel, reducing heat-transfer efficiency. They are ethylene glycol based and should never be used for food application.
Which Heat transfer fluid should I use?
The decision to choose a synthetic organic fluid, a silicone fluid, or an inhibited glycol-based fluid is largely based on application temperature requirements. If your heat transfer application has a maximum use temperature requirement above 175oC (350oF), you should investigate “high temperature” synthetic organic and silicone fluids. We do not offer organic or silicone based thermic oils. We have ROTO range glycol-based heat transfer fluid.
However, if your maximum use temperature will be lower than 175oC (350oF), or if you need freeze protection for a water-based system, consider using a “low temperature” inhibited glycol-based fluid.
Inhibited glycol-based fluids are solutions of water and inhibited glycols. The concentration of glycol in the fluid directly affects its performance properties and is specified by the user to meet specific application (typically minimum temperature) requirements.
Why should you use glycol with dye?
The dye in the glycol acts as an indicator and helps us identify and leaks. This is imperative in food and beverage facilities. We provide both food grade glycol dye and industrial grade glycol dye. Check out our products page for more information