What is a Glycol Makeup Unit or Glycol Filling Station?
The glycol makeup unit is a pre-packaged system that allows for pre-mixed glycol solutions to be introduced into a system with the purpose of maintaining the proper system pressure. These packages include a glycol fill pump, a glycol holding tank, a pressure regulating valve, interconnecting piping and a simple control system.
Why should I install the Glycol Makeup Unit in my system?
When a system is filled with a glycol mixture such as 40% DOWFROST HD, it is important to maintain the proper concentration of the glycol. As air is removed from the closed system, the pressure in the system drops. At that time, the makeup system adds fluid to the system to bring the pressure back up to the desired setting. Adding water to your glycol system will reduce the concentration over time and could result in lost protection in the system. Having a glycol makeup unit with a 40% pre-mixed solution of 40% DOWFROST HD in the glycol holding tank ensures that the concentration is kept at the desired levels.
Where should I install the Glycol Makeup Unit in my system?
The glycol makeup unit should be installed in the same location as the typical pressure regulating valve would be in a water system as it is serving the same purpose. As shown in the diagram, the unit should be piped at the air separator and expansion tank. It is often piped with the air separator vent line to help vent any air that might be introduced by the glycol makeup unit.
What type of piping should I use when piping my Glycol Makeup Unit?
Piping is typically steel or copper. Be sure to check the connection fittings to ensure any opportunity for galvanic reaction is eliminated. This article can help you choose the best piping material based upon the glycol you use in your system. To learn more about which glycol is best for your application, click here.
How is the Glycol Makeup Unit controlled?
There are four main components to the glycol makeup unit control system. All of these items are pre-piped in the glycol piping or in the makeup tank. The first component is the control panel which is nothing more than a basic starter with a pilot light, a low-level horn and a couple sensors. One of the sensors is a low-level sensor located in the makeup tank that will stop the pump if low levels of fluid are detected. This protects the pump from running dry as well as signals the horn to make the maintenance team aware that the fluid is low. The second sensor acts as a high pressure sensor and is located on the pump discharge. This sensor stops the pump once the pressure limit is hit. The last component is the pressure regulating valve. This valve is a mechanical means of setting the desired pressure at the discharge of the glycol makeup unit, which is the same as the system cold fill pressure. The valve is open when the pressure downstream of the valve is below the setting and is closed when the pressure downstream of the valve reaches the set pressure.
These four components work together to provide the proper fill pressure, to start and stop the pump as pressure drops and is recovered, and to stop the pump if the glycol tank requires more premixed glycol solution.
The glycol makeup unit, or glycol filling station, is a critical part of your systems operation. It helps maintain the proper glycol solution which helps keep your system protected at all times. It’s a low-cost solution to keep your system in tiptop shape!
MEET THE PRO: JOSH LOOPER
Josh earned his BS degree in Mechanical Engineering from Case Western Reserve University. He also holds a PE license. Josh has been an integral part of the team for 16 years. In his spare time, Josh spends time with his wife and four daughters, plays golf, volunteers with local charities and plays an active role in his church.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>There are many propylene glycol uses in the world, but is it necessary to add glycol to water in hydronic heating systems? What about adding glycol for cooling systems? This article explains why adding glycol to water provides important protections.
Water is the Basic Fluid used in Hydronic Heating and Cooling Systems
Many building heating and cooling systems use water to move temperatures around the building. The water is heated or cooled, and pumps transport the water to the various coils where air takes the heat or cooling into the space.
To maintain good indoor air quality, fresh air must be brought into the building while some air is exhausted. The air is pulled in by fans located in air handling units and is the same temperature as the outdoor air. In northern climates, the incoming air temperature can be very cold. Care is exercised during the design to assure that the ice-cold air does not freeze the water but things can go wrong.
Three Example Systems Where Adding Glycol Can Save the Day
Example #1: Air Handling Unit Freeze Protection
Look at the photo above. This heating coil uses a two-way control valve with the main heating pumps operating on variable speed drives. This will save energy and operating costs.
The downside of the system is the concern about stopping the flow through the coil where cold air is rushing in. Engineers use a piping practice named primary-secondary to assure there is always flow across the coils. The primary-secondary piping depends on a small circulator pump to move the water around.
If the circulator pump fails, the flow may stop, and cold air could freeze the water and damage the coils. Many engineers will use a percentage propylene glycol antifreeze mixed with the water to avoid catastrophic coil damage.
Example #2: Glycol Chillers not used in the Winter
Many HVAC systems have air cooled chillers used throughout the summer. In the winter they are drained so they do not freeze. This provides two problems for owners.
What happens when we get a hot spell in the fall. The people in the building are hot and they do not blame the system, they blame the operations people. Adding glycol to cooling systems will allow the use in both summer and winter.
The second problem occurs when the cooling system is started. Many owners simply open the valves to the air cooled chiller and allow the system and the makeup water to fill the pipe. This causes a large amount of air to be introduced into the system. This air will cause cooling problems for weeks or even months.
When people ask, what is a glycol chiller? The answer could simply be a chiller that can run all year if needed. Remember that not any old antifreeze will do. The glycol used in chilled water systems should be the right percentage and have the right mix of inhibitors. Try our glycol concentration calculator to determine the required concentration for your application or contact us today for help finding the correct solution for your application.
Example #3: Pipe in Unheated Spaces
We showed above the glycol chiller can be used all year round. There is another concern with piping systems where there is no flow at times. Often these pipes may run through unheated spaces or spaces with cold outside air blowing across the pipe.
Sometimes the design included heat in a space to protect the chilled water or heating system. During the life of the building the space becomes unused. To save money, the owner may turn the heat down or even off. Water may freeze but a glycol antifreeze system will protect the pipe.
Additional Advantage of Glycol in Closed Hydronic Heating and Cooling Systems
Not all glycols are the same. The Dowfrost® and Dowtherm® products supplied by Go Glycol Pros include an inhibitor package which protects the pipe much better than water or even water with chemicals added. Click here to learn more about the benefits of inhibited heat transfer fluid.
Adding the proper type, concentration (or mix), and brand of glycol to closed heating and cooling systems will offer protection. Glycols and antifreeze should not be added to systems without an understanding of the effects on pumps and heat or cool output. For assistance in getting started, contact our customer service team today!
MEET THE PRO: NORM HALL
Norm graduated from Wayne State University in Electrical Engineering. Over the past 40 years at RLD Norm has worked on design/engineering of systems, estimating, outside sales & management. Norm enjoys golf, playing with his grandkids, teaching eighth grade catechism classes, and volunteering at local food banks.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>What is the Freeze Point?
The freeze point is the temperature where ice crystals begin to form in the fluid and the fluid becomes slushy, but it does not expand.
What is the Burst Point?
The burst point is the temperature where the fluid will freeze solid, expand, and break pipes or damage coils, fittings, or valves in the system.
What is Freeze Protection?
For freeze protection, the system requires a glycol concentration that is sufficient to prevent the formation of ice crystals at the lowest temperature the system will experience. Freeze protection is important when the system requires pumping. For example, an on-off type snow melt system where the fluid could be sitting in a very low temperature slab and then be called on to be pumped to start the snow melt process. When it is turned on, you do not want to be trying to pump slush.
What is Burst Protection?
For burst protection, the glycol concentration needs to be high enough to prevent bursting or other damage to equipment, but not necessarily high enough to maintain the fluid in a pumpable state. For example, you would need burst protection for a chilled water system that sits dormant in the winter and is exposed to freezing temperatures but the pumps won’t be energized and try to cause the fluid to flow through the system. Burst protection requires less glycol than freeze protection.
In a system with burst protection, as the ambient temperature drops and the fluid cools, ice crystals form and the fluid will become slush. The fluid will expand as ice is formed. We may not be able to pump the slush, but it is fluid enough so that any additional volume will flow into the expansion tank without damage to the piping or components. As it gets colder and all the water freezes the glycol also begins to freeze and contract, again providing the desired burst protection.
How to Know if System Requires Glycol?
The most common uses for glycol in HVAC systems is for snow melt, chilled water, ground source heat pump, and hydronic systems that require protection due to their location, maybe buried in a concrete slab or possibly outside on a roof. Once it is determined that the system needs glycol and what level of protection the glycol needs to provide (either freeze or burst protection), how do we determine the required concentration of glycol?
How to Determine Required Concentration of Glycol?
There are two types of HVAC grade glycols commonly used in our industry, propylene glycol and ethylene glycol. These are not the same thing as the anti-freeze you put into your car’s radiator. Go Glycol Pros supplies DOWFROST and DOWFROST HD propylene glycol, and DOWTHERM SR-1 ethylene glycol. There are inherent differences between the propylene and ethylene glycol. Click here to learn more about these two types of glycol. It is important to note that both propylene and ethylene glycol provide the cold temperature protection needed; however, they require different concentration levels to do so. For example, at 10°F DOWTHERM SR-1 ethylene glycol will provide freeze protection with a concentration of about 26% and it provides burst protection at about an 18% concentration. At that same temperature, the system would need a concentration of about 30% DOWFROST HD propylene glycol for the freeze protection and about 21% for burst protection.
To determine what concentration of ethylene or propylene glycol is needed, use our easy concentration calculator. Alternatively, you can utilize the below concentration charts provided by Dow.
Propylene Glycol Freeze Chart
Ethylene Glycol Freeze Chart
Notice in the notation below the charts that minimum concentration levels are recommended to provide adequate corrosion protection and prevent bacterial contamination, both very important items to consider.
You can find and download the DOWFROST, DOWFROST HD and DOWTHERM SR-1 engineering specifications from our material library here.
MEET THE PRO: GERRY POTAPA
Gerry has been in the industry for over 40 years. He worked as a consulting engineer from 1977 until 2010 when he joined our team. He enjoys spending time with his family, hunting, fishing and all outdoor activities. He is also a past President of the Band Boosters at his daughter’s high school.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>Whether the hydronic system you plan to fill with a glycol mixture is new or whether it’s existing, flushing and cleaning the system will help not only to maintain proper heat transfer capabilities but also extend the life of the equipment in the system.
Why Flush the System?
In newly installed systems, chemicals and debris from the installation of piping like oil, grease, solder flux, and pipe scale will intensify the degradation of the glycol mixture. In existing systems, rust, scaling, and sediment build up tied together with exposure of the glycol mix to high temperatures will produce the same results: in time, the glycol will turn into glycolic acid and need replaced.
Flushing and Cleaning
It’s important to understand that flushing and cleaning the hydronic systems are two different things. Flushing allows us to remove the contaminates of a newly commissioned hydronic system and can also help to remove old, degraded glycol from the system before transitioning to a different fluid make up. Flushing does not eliminate sludge and build up that has developed within the system over time. Cleaning on the other hand does. Cleaners can be delivered to the system in a few ways; some are added to the heat transfer fluid and help to break down carbon deposits and sludge over time, while others are solvents that we purge through the system when not in operation.
How is it Done?
In general, to start, we want to fill up the hydronic system with water and start up our pumps and boiler; we should be heating the water up to at least 140 degrees Fahrenheit. After the system has been circulating for some time, samples of the water should be taken to determine whether or not we are seeing solids floating in the sample. If so, we should be sure to clean out any debris that may be held at the pumps suction diffusers, Y strainers, or strainer baskets. This process should be continued until we are not witnessing solids in our water samples. Now is when a cleaning solution should be added to the system and allowed to circulate for the manufacturer’s suggested amount of time and temperature. Once drained, we again want to flush the system until we are seeing water samples that no longer contain remnants of contaminants dislodged by the cleaner. Once clear, we should then drain the system entirely before filling back up with a pre-mixed solution of glycol and water that meets the specifications called for by the engineer.
If you need advice on flushing or cleaning your heat transfer system, contact Go Glycol Pros today! Our helpful heat transfer specialists can help to identify what's needed for your upcoming project.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>If you are looking to add glycol to an existing heat transfer solution, but don't know the makeup of your current fluids, is it ok to add whatever glycol you have on hand?
Or maybe you're interested in switching to a different glycol type than you have used in the past. Do you need to drain and flush the system before switching?
For both of these questions, it is important to note that not all glycols are created equal. There are formulaic differences between propylene glycol and ethylene glycol and even between different brands of the same glycol type.
Due to these differences, mixing propylene glycol and ethylene glycol is highly discouraged. In this article, we will discuss which type of glycol is best for your application and why you should drain and flush your system before adding a new type of glycol.
Which Type of Glycol is Best?
Glycol is used in heat transfer solutions to provide protection against freezing temperatures and corrosion. Both propylene glycol and ethylene glycol do a great job of providing these protections. The answer to our question of "which is best" lies in understanding your application and determining which solution will best fit the needs of the job. Let's explore the primary differences between propylene glycol and ethylene glycol.
The primary difference between propylene glycol and ethylene glycol are the toxicity and heat transfer characteristics.
Propylene glycol fluids are often selected because of their low acute oral toxicity vs. the moderate acute oral toxicity of ethylene glycols. However there is a tradeoff between lower oral toxicity and heat transfer efficiency: ethylene glycol has a lower viscosity than propylene glycol. This means its transport properties outperform propylene glycol at lower temperatures.
In summary, where oral toxicity is a concern, choose propylene glycol for your application. It will provide you heat transfer with protections against freezing temperatures and corrosion.
However, if oral toxicity is not a concern, ethylene glycol is the industry standard. It provides excellent heat transfer, freeze protection and corrosion resistance.
Why Can't I Mix Propylene Glycol and Ethylene Glycol?
Ethylene and propylene glycol have different fluid, toxicity and heat transfer characteristics that will prevent your system from operating correctly when mixed. If you require a food grade propylene fluid, mixing ethylene glycol will create a hazard that requires a complete drain, clean and flush before refilling with correct glycol fluid.
Also, because of the formulaic differences, when you mix two different types or brands of glycol, you reduce the corrosion resistance and interfere with the solutions concentration, which can leave you vulnerable to freezing temperatures.
Finally, mixing can often lead to problems with the system and the glycol itself. Mixing can lead to separation, which can then cause a gel to form that will block filters and strainers, causing damage to the system.
For these reasons, many brands will void their warranty if solutions are found to have been mixed, including Dow.
So if you know you'd like to change up your glycol, here's how to do so safely.
How to I Change Out My System Fluids Safely?
Here the steps to take when switching glycol types or brands:
If you have additional questions, contact us today! Our heat transfer experts are ready to help find the right solution for your needs.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>Dow inhibited glycol fluids have set the HVAC industry standard for freeze protection and heat transfer for over 80 years. As the nation’s largest glycol producer, with over 90 stocking locations in North America alone, they are equipped to help meet your evolving needs. This article covers testing for the below glycol products from Dow:
Sample Analysis Program Requirements
To help ensure that corrosion and freeze protection are maintained in customer systems, Dow offers a fluid analysis service to qualified customers. It is designed to assure the long-term performance of Dow glycol-based heat transfer fluids and to help minimize replacement fluid requirements, system maintenance, and repair costs. Dow's Customer Service Laboratory provides a free annual fluid analysis for customers having a system size greater than or equal to 250 gallons of thermal fluid concentrate.
Dow provides the testing service for a fee of $200.00 per sample to any customer who system does not meet the minimum fluid requirement.
Fluid Testing
Typically performed on an annual basis, the analysis includes measurement of the ethylene or propylene glycol concentration, pH, reserve alkalinity, inhibitor levels, water condition, and contaminants (chloride, sulfate, nitrate, and total hardness), as well as a visual inspection of the fluid for color, clarity, and sediment.
Sample Kit
Dow has a complementary Thermal Fluids Sampling Kit for customers who have purchased Dow fluids. This kit permits easy and accurate labeling of fluid samples and safe shipment of samples to Dow for analysis. If you have purchased from Go Glycol Pros in the past, you may request your free kit here.
How the Service Works
After the system has been filled and circulated for 24 hours, an initial four-ounce sample should be withdrawn and sent to Dow using one of the Thermal Fluids Sampling Kits. Remember to closely follow the sampling instructions. Proper sampling is essential to ensure meaningful assessment of the fluid condition.
Approximately two to three weeks after the sample is received by Dow, a report will be sent to you, via e-mail, or fax, detailing the results of the analysis plus any recommendations.
Prior to Sampling
Prior to sampling, the system fluid will not separate nor will the inhibitors drop out of solution upon standing, however it is recommended to obtain a sample from a well-mixed system to assure a representative sample.
The sample should not be taken from a point of low flow, where accumulated solids would not be representative of the general condition of the system fluid.
Sampling Procedure
Dow Inc.
633 Washington St.
1712 Building - Thermal Fluids
Midland, MI 48667
If you need an extra Customer Information Sheet, please click here.
Reference Source: Dow Customer Service
MEET THE PRO: MARK FINE
Mark graduated from Lawrence Technological University with a Bachelor of Science in Mechanical Engineering. He takes pride in his work and values the close ties with his customers. Mark is supported by his wonderful wife, Lisa and his beautiful children Kailee, Joshua and Jessica. For pleasure, he enjoys boating, golfing, concerts and trips with his family.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>An irregularity exists within the properties of water and ice. It turns out, at 39.16 degrees Fahrenheit, water reaches its greatest density, even greater than the density of its solid form, ice. Consequentially, this causes an issue when it comes to utilizing water to carry heat or cooling around our buildings to provide temperature control and comfort to building occupants.
For example, how do we protect the piping and other equipment in a hydronic heating system from bursting in the event the heat generators are down and the water in the system approaches freezing temperatures?
Answer: We lower the freezing point of the water in our system by adding in a specific amount of glycol.
Types of Glycol
In the hydronics world, two types of glycol are used: propylene glycol and ethylene glycol. What is the difference between the two?
There are two main factors to consider; first, ethylene glycol is a more toxic substance than propylene glycol and it can be harmful if ingested. In heating systems where there is potential exposure to the system fluid or there are chances of the glycol contaminating potable water, we avoid its use. Only in strictly regulated industrial environments do we see ethylene glycol being used in today’s world.
Propylene glycol, on the other hand, has been approved as safe by the FDA. Because of the low oral toxicity, it is commonly used in packaged foods, drugs, and cosmetic products.
So why not use propylene glycol every time? The answer is: Heat Transfer.
It turns out that the lower freezing point advantages we gain from glycol come at a cost, and that cost is poorer ability to transfer heat. The often-used equation in the world of hydronics to compute total heat transfer from the flow rate at which the water is traveling and the temperature delta we plan for across our coils is often expressed as:
BTUH = GPM * dT * 500
What is frequently left out is the fact that this equation only represents the total heat transfer when our fluid is pure water. Once we introduce glycol, we must take into account the significant difference in the specific heat of the glycol mixture as compared to pure water.
For instance, propylene glycol at a 40% concentrated mix with water produces a specific heat of 0.895. That drop ultimately reduces the total amount of heat transfer we are able to achieve with identical flow rates and temperature deltas as compared to 100% water.
However, ethylene glycol solutions do not impact specific heat as much as propylene glycol solutions, and therefore provide better heat transfer at the same mixture percentage (glycol concentration).
Below is the adjusted formula for total heat transfer taking into consideration that the solution is not made from pure water, but instead includes glycol:
BTUH = GPM * dT * 500 * Specific Heat * Specific Gravity
Freezing and Bursting
This might sound confusing, but these are two different things when we talk hydronics. Freeze protection refers to the total elimination of a phase change occurring to solid form at a specified temperature; in this scenario, the fluid in the system will always stay in liquid form all the way down to the worst case temperature scenario determined by the design team.
Compare that to burst protection which allows part of the fluid in the system to achieve a phase change and create a slush like consistency in the piping, but prevents total freezing from occurring which would ultimately burst the pipes.
If a system containing glycol does in fact spring a leak, the coloring dye added to the solution during the manufacturing process helps to identify the location of the leak.
What Concentration Do You Need?
Concentration will depend on the type of glycol used, the lowest anticipated ambient temperature and whether you desire freeze protection or burst protection. Click here to learn more about calculating required glycol concentration or contact us today!
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>
This article will answer safety concerns associated with the safety of both propylene and ethylene glycol solutions. It will be important to remember that this article is referring to inhibited glycols such as DOWFROSTTM and DOWTHERMTM propylene glycol and ethylene glycol solutions.
Is propylene glycol safe?
The short answer is “Yes.” There are very few hazards associated with inhibited propylene glycols such as DOWFROSTTM and DOWFROST HDTM.
Is ethylene glycol safe?
This answer is a bit more complicated, but still fairly simple. While inhibited ethylene glycols such as DOWTHERM SR-1TM are generally safe, there are some hazards that one should be aware of, especially when compared to propylene glycol.
Where can I find glycol safety information?
The best place to start when trying to understand if propylene glycol is safe and if ethylene glycol is safe is to review their respective SDS sheets. What is an SDS? It is an acronym for Safety Data Sheet. In the past, they have been referred to as MSDS or Material Safety Data Sheet. You can access the various SDS sheets for various mixtures of DOWTHERM SR-1TM, DOWFROSTTM and DOWFROST HDTM in our Library of Glycol SDS and Properties Charts.
These SDSs indicate a broad range of information including Hazards, First Aid Measures, Firefighting Measures, Handling & Storage, Disposal Considerations, Transport Information, and a plethora of other items.
It is on these sheets that you will see that DOWFROSTTM is not considered a hazardous material (SDS page 1) and that no emergency medical treatment is required if ingested (SDS page 2). DOWTHERMTM, on the other hand, is considered hazardous (SDS page 1) and requires special care if ingested (SDS page 3).
For additional handling and safety information, check out our article on How to Handle, Store and Safely Dispose of Used Propylene and Ethylene Glycol.
What do I need to know if I am transporting glycol?
The first thing to understand is what containers are OK to use. The SDS will indicate suitable materials for the container. Note that GoGlycolPros.com only uses suitable materials when shipping glycol.
You will also want to understand any special transportation numbers that may be required. This would include the UN (United Number) or NA (North American) numbers. These too are listed on the SDS, if applicable. You will see that DOWFROSTTM propylene glycol is not regulated and does not have a UN number. However, DOWTHERMTM ethylene glycol is regulated and its UN number is 3082. This designation helps transport professionals better understand the fluid they are moving.
Another key piece of information is understanding how to handle any spills. The propylene glycol safety data sheet indicates very similar actions as the ethylene glycol safety data sheet. In both cases, the fluid should NOT be dumped down a sewer, on the ground or into any body of water.
The final number you may come across is something called a CAS Registry Number, also known as a CASRN or CAS Number. This is a unique numerical identifier assigned by the Chemical Abstracts Service (CAS) to every chemical substance. The CASRN might be referenced for regulatory purposes and can be found in the Safety Data Sheet.
Where Should I Keep My Safety Data Sheets?
It is best to not only read and understand the glycol safety data sheets but to also keep one handy anywhere you use glycol. While both propylene glycol and ethylene glycol are relatively safe, there are some special considerations to heed should an accident occur. Inhibited glycols such as Food Grade DOWFROSTTM Propylene Glycol, DOWFROSTTM HD Propylene Glycol and DOWTHERMTM Ethylene Glycol are great additions to your heating and chilled water systems; and, if used as directed with the proper precautions, they are both very safe.
MEET THE PRO: JOSH LOOPER
Josh earned his BS degree in Mechanical Engineering from Case Western Reserve University. He also holds a PE license. Josh has been an integral part of the team for 16 years. In his spare time, Josh spends time with his wife and four daughters, plays golf, volunteers with local charities and plays an active role in his church.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>Ask any HVAC test and balance technician in the hydronic system world to convert PSI to feet of water (or feet of head), and a multiplier of 2.31 is the immediate response. It is a simple conversion we learn early in our careers.
However, there are times when the multiplier for the conversion of PSI to feet of head (PSI to ft head) changes. Since specific gravity is normally close to one for water but is not so in glycol systems, pump differential pressure gauge readings from a hydronic glycol system require an adjusted multiplier to account for the change in specific gravity.
Failing to adjust the multiplier for glycol fluid may result in an assumed flow rate that doesn’t match the design, and when temperatures become really hot or cold, you may not be able to meet the occupants’ temperature requirements.
In this article, we will explore an example to illustrate the importance of adjusting the multiplier based on type of heat transfer fluid.
Formula to Calculate Feet of Head for Water System
Feet of Head (Ft of Water) = (PSI X 2.31 Multiplier) / Specific Gravity
Feet of Head (Ft of Glycol) = (PSI X Multiplier from Table Below)
Table of Multipliers for Glycol Systems
Propylene Glycol (DOWFROST or DOWFROST HD) | ||
---|---|---|
Concentration (% Glycol) | (M) 35°F to 120°F | (M) 121°F to 190°F |
Water Only | 2.31 | 2.36 |
20% | 2.25 | 2.31 |
25% | 2.24 | 2.30 |
30% | 2.23 | 2.29 |
35% | 2.21 | 2.27 |
40% | 2.20 | 2.27 |
45% | 2.19 | 2.26 |
50% | 2.18 | 2.25 |
Ethylene Glycol (DOWTHERM SR-1) | ||
Concentration (% Glycol) | (M) 35°F to 120°F | (M) 121°F to 190°F |
Water Only | 2.31 | 2.36 |
20% | 2.24 | 2.29 |
25% | 2.23 | 2.28 |
30% | 2.21 | 2.26 |
35% | 2.20 | 2.25 |
40% | 2.18 | 2.23 |
45% | 2.17 | 2.22 |
50% | 2.15 | 2.21 |
a) Chart accuracy or rounding is ± 0.02 | ||
b) Chart is based on the % by volume of DOWFROST mixed with water | ||
c) ®™Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow |
Does it Make a Difference in the Test and Balance Report?
In this example, we have a design condition of 1000 gallons per minute (GPM) at 90 feet. The heat transfer fluid is 50% Dowfrost HD (propylene glycol) at 40°F. The glycol concentration is known because the system fluids were purchased premixed with deionized water (DI water) from Go Glycol Pros.
If concentration is unknown, we recommend you use a refractometer to measure current glycol concentration.
Assume the pump differential pressure was 40 PSI.
40 PSI x 2.31 multiplier = 92.4 ft of head
This would indicate we are flowing 950 GPM or 5% below the design flow rate. If the test and balance technician uses the correct multiplier from the glycol table above, the multiplier would be 2.18.
The revised calculation is:
40 PSI X 2.18 multiplier = 87.2 ft of head
With the proper correction, the flow rate indicated is now 1050 GPM.
This simple example shows the balance report would be off by 10%. The report would indicate a lack of flow rather than the 5% additional flow that will occur.
Therefore, without the proper correction or adjustment to the multiplier for pumps with glycol heat transfer fluid, you may end up over pumping and wasting energy, or failing to meet the heating or cooling requirements due to under pumping.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
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Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>When servicing hydronic equipment, we often take the following steps:
What happens to glycol in HVAC systems? Once the fluid is replaced, the glycol solution may be diluted to a concentration lower than design. A system with overly diluted glycol leads to undesired performance, a reduction of corrosion inhibitors, and (for colder climates) a reduction in freeze/burst protection. Correcting glycol concentration is easy using on-site heat transfer fluid testing.
Refractometer Test
We recommend testing your heat transfer solution concentration whenever the system has been serviced using an easy, on-site fluid analysis tool such as a refractometer. Refractometers measure the glycol concentration and gives the antifreeze freezing point. This instrument requires only a few drops of fluid for glycol testing and requires no adjustment for fluid temperature.
The below video demonstrates how to test your system using a refractometer.
Please find below the Freezing and Boiling Points chart used in our how-to video for both DOWFROST and DOWFROST HD Propylene glycol and DOWTHERM SR-1 Ethylene Glycol.
Propylene Glycol Freezing and Boiling Point Chart (DOWFROST and DOWFROST HD)
Ethylene Glycol Freezing and Boiling Point Chart (DOWTHERM SR-1)
Upon completing your glycol testing, you may need to increase your system's concentration using glycol addition. Our concentration correction calculator makes it easy to determine how much glycol is needed (100% concentrated) to bring your solution back to the required levels. See our glycols available for purchase online here.
Need additional help? Contact us today.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>In this article, we will discuss two methods to accurately measure system volume of heat transfer fluids. While neither are 100% precise, they will get you a close approximate volume which can be used to place your order.
If you have questions about measuring how much glycol is needed or need help with an upcoming heat transfer project, contact us today.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>You have selected a glycol fluid and pumped it into your system along with high quality fill water. Now what?
Regular glycol testing in HVAC systems is key to avoid unforeseen maintenance costs or unscheduled shutdowns. Somewhere down the road, changes may occur in the system which could affect the heat transfer solution. For example, periodic leaks in the system components or piping may require adding more fluid. The proper course of action would be to add as much glycol fluid as needed to bring the system solution back to the required level of concentration. However, glycol addition often does not happen, especially if the system has an automatic water makeup valve. Proactively testing, observing and maintaining your heat transfer solution on a regular basis will extend the life of your Dow® chemical heat transfer fluids for more than 20 years!
In this article, we will discuss four testing methods you should add to your to-do list today:
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
]]>Why Hard Water Can Mean Trouble
Where hard water (also city water or plain water) is used to dilute industrially inhibited glycol concentrates, the inhibitor will react with the ions in the water and fall out of the solution. This forms sludge and sediment that reduce heat transfer efficiency and can lead to fouling and corrosion. This is due to greater levels of "hard water ions" (calcium and magnesium).
Impurities found in hard water can increase:
And can reduce:
To avoid these potential issues, Dow recommends that water used for dilution purposes meet the below minimum specifications.
Don't Panic if You've Already Filled with Hard Water
If you've already filled your system with hard water, all is not lost. Dow has taken steps to help counteract the effects of hard water by including patented anti-scaling and hard water stabilizing technology in DOWTHERM SR-1 ethylene glycol and DOWFROST HD propylene glycol. Their patented additive enables these fluids to work effectively in solutions with hard water. However, other contaminants will still be present in the hard water, so when you can use deionized, demineralized or suitably pure water, be sure to do so.
Note: The anti-scaling and hard water stabilizing additives are not included in DOWFROST food grade propylene glycol.
Demineralized Water Vs. Deionized Water
Deionization and demineralization, while being similar, have key differences. Deionization removes ionized salt from the water. Demineralization removes minerals from the water such as calcium, magnesium and many others. Much of the drinking water that we consume goes through both processes. Both can be used in heat transfer fluids and are superior to using plain or hard water.
Where to Buy Deionized Water (Buy DI Water)
Go Glycol Pros is a deionized water supplier. We offer bulk deionized water for sale in 5 gallon pails, 55 gallon drums and 275 gallon totes here.
If you have questions about fill water or your current HVAC project, contact us. Our experienced customer service team has the product, system and HVAC know-how to assist you.
Go Glycol Pros is a distributor of DOW® heat transfer fluid for over 20 years. We sell glycol online with no accounts or order minimums required. Available in 275 gallon tote, 55 gallon drum or 5 gallon pail, high purity DOW antifreeze is premixed with deionized water (DI water) at our in-house facility and ships out within just one business day. Our inhibited glycols include: DOWFROST HD propylene glycol, DOWFROST food grade propylene glycol and DOWTHERM SR-1 ethylene glycol.
Explore more helpful tips and advice at goglycolpros.com. Our knowledgeable glycol experts are ready to help you with your latest hydronic HVAC project.
View Dow Ethylene Glycol, Propylene Glycol and Food Grade Propylene Glycol
Sign Up to Receive Heat Transfer Tips and Advice from Go Glycol Pros
Disclaimer: Go Glycol Pros and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the- information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.
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