When you click this help button on the Calculate Fluid Properties screens, you can obtain definitions or explanations by clicking on highlighted items.
Offered for more than 80 years, Dow synthetic fluids include DOWTHERM™ synthetic organic fluids and SYLTHERM* silicone fluids. Each DOWTHERM fluid offers outstanding thermal stability for efficient heat transfer, extended fluid life, and optimum operating economics. All DOWTHERM fluids have vapor pressures lower than steam and three fluids are designed to be used in non-pressurized systems. SYLTHERM fluids are essentially odorless and low in acute oral toxicity. In the U.S. they are not listed as reportable under SARA Title III, Section 3131. They provide excellent heat transfer performance and can provide exceptionally long service.
To maximize service life, choose a synthetic organic offering sufficient thermal stability to accommodate maximum planned operating temperature and allow for unplanned excursions above that level. While the initial purchase cost of silicone fluids may be higher, in many cases the use of a silicone fluid can result in lower long-term expense because they degrade differently than other fluids and typically do not require complete change out. Calculate and compare properties based on your specific system conditions.
DOWTHERM™ Synthetic Organic and
SYLTHERM* Silicone Heat Transfer Fluids
At appropriate concentrations these fluids will provide burst protection to -73°C (-100°F)
Synthetic Organic Fluids
DOWTHERM™ A ─ DOWTHERM A heat transfer fluid is a eutectic mixture of two very stable compounds, biphenyl (C12H10) and diphenyl oxide (C12H10O). One of the industry’s most widely used high temperature fluids – and a leading fluid used in large-scale concentrated solar power (CSP) installations, DOWTHERM A fluid may be used in systems employing either liquid phase or vapor phase heating.
DOWTHERM G ─ DOWTHERM G heat transfer fluid contains a mixture of di-ethers and diaryl alkyls that offers remarkable performance in liquid phase heat transfer systems. It is one of the most thermally stable low pressure liquid phase heat transfer fluids on the market and has excellent flow characteristics at low temperatures.
DOWTHERM J ─ DOWTHERM J heat transfer fluid is a mixture of isomers of an alkylated aromatic specially engineered for demanding low-temperature applications in liquid phase pressurized systems. DOWTHERM J fluid offers remarkable low-temperature pumpability and thermal stability for protection against accidental overheating. Suitable applications include single fluid heating and cooling. DOWTHERM J can also be used for vapor phase heating and cooling.
DOWTHERM MX ─ DOWTHERM MX heat transfer fluid is a mixture of alkylated aromatics designed for use as an alternative to hot oils in liquid phase heat transfer systems. DOWTHERM MX fluid is suitable for use in non-pressurized systems; its good low temperature properties allow for low temperature start-up and pumpability. Expansion Tank Design: Even though DOWTHERM MX fluid can be operated in a non-pressurized system, it is recommended that the tank have an inert atmosphere. Nitrogen padding should be used on the expansion tank to exclude oxygen from the heat transfer system. The presence of oxygen will cause accelerated fluid degradation, which will considerably shorten the life of the fluid.
DOWTHERM Q ─ DOWTHERM Q heat transfer fluid contains a mixture of diphenylethane and alkylated aromatics. Compared to hot oils, it exhibits better thermal stability, particularly at the upper end of hot oils' use range, and significantly better low-temperature pumpability. Suitable applications include use as an alternative to hot oils in liquid phase heat transfer applications.
DOWTHERM RP ─ DOWTHERM RP heat transfer fluid is a diaryl alkyl intended for use in applications that require liquid phase heat transfer. Unlike other low pressure fluids — including partially hydrogenated terphenyls and dibenzyl toluene fluids — DOWTHERM RP fluid degrades primarily to low molecular weight products. This reduces the need to remove high molecular weight material from the system, resulting in longer fluid life and, coupled with the superior thermal stability, results in reduced fluid makeup requirements, less system downtime, and lower fluid and maintenance expense over the life of the heat transfer system. Suitable applications include non-pressurized or low pressure liquid phase systems including polyester, nylon, and other synthetic polymer processing facilities.
DOWTHERM T ─ DOWTHERM T heat transfer fluid is a mixture of C14-C30 alkyl benzenes intended for use in applications that require liquid phase heat transfer. Suitable applications: Non-pressurized liquid phase systems with a maximum temperature of 550°F (288°C).
SYLTHERM* 800 ─ SYLTHERM 800 heat transfer fluid is a highly stable, long-lasting silicone fluid designed for high temperature liquid phase operation. It exhibits low potential for fouling and can often remain in service for 10 years or more at 400°C (750°F). SYLTHERM 800 has essentially no odor and is low in acute oral toxicity.
SYLTHERM XLT* ─ SYLTHERM XLT heat transfer fluid is a specially formulated, high performance silicone polymer designed for use as a low temperature, liquid phase heat transfer medium. It offers remarkable low temperature heat transfer and pumpability, plus thermal stability. SYLTHERM XLT fluid has essentially no odor, is low in acute oral toxicity and is not listed as reportable under SARA Title III, Section 3131. Suitable applications include: Single fluid process heating and cooling systems in the pharmaceutical and fine chemical industries.
SYLTHERM* HF ─ SYLTHERM HF heat transfer fluid is a specially formulated, high performance silicone polymer designed for use as a low temperature, liquid phase heat transfer medium. It offers remarkable low temperature heat transfer and pumpability, plus thermal stability. With a closed cup flash point above 140°F (60°C), SYLTHERM HF fluid can provide an extra margin of safety and can reduce system and engineering costs. SYLTHERM HF fluid has essentially no odor, is low in acute oral toxicity and is not listed as reportable under SARA Title III, Section 3131. Suitable applications include: Single fluid process heating and cooling systems and environmental test chambers.
Process Heating and Cooling ─ DOWTHERM™ synthetic organic and SYLTHERM* silicone fluids are widely used in the chemical process industry because of their high temperature stability. Process applications include polyester, PET, nylon, LAB (linear alkyl benzene), phthalic anhydride (PA), purified terphthalic acid (PTA), dimethyl terphthalate (DMT), olefins, alcohols, plasticizers and a variety of other petrochemicals. Each chemical process has different operating parameters that will guide selection of the best heat transfer fluid. The family of DOWTHERM and SYLTHERM heat transfer fluids includes a broad range of products with recommended operating temperature ranges to address the requirements of nearly any chemical process.
Fine Chemical Batch Processing ─ SYLTHERM XLT* silicone fluid has a broad operating temperature range of -100°C (-150°F) up to 260°C (500°F), making it especially well-suited for single-fluid process heating and cooling systems. Also useful is DOWTHERM J synthetic organic fluid with a recommended liquid phase operating temperature range of -80°C (-110°F) up to 315°C (600°F).
Waste Heat Recovery ─ Many processing operations require heat removal or cooling or have on-site power generating equipment. The heat from these processes can be recovered through the use of conventional heat exchangers, using liquid phase and/or liquid and vapor phase heat transfer fluids. This waste heat can be circulated to heat downstream processes or otherwise recycled and recovered. This helps reduce overall energy costs. Several DOWTHERM heat transfer fluids are particularly well-suited for heat recovery operations. These thermally stable, non-corrosive products transfer heat efficiently and effectively in a wide range of processing environments.
Concentrated Solar Power
Concentrated Solar Power ─ DOWTHERM™ A fluid is used in Concentrated Solar Power (CSP) systems to collect heat energy captured from the sun and transport it to a power generating station. The transported heat converts water to steam which in turn drives turbines to make electricity. DOWTHERM™ A is a synthetic organic fluid capable of operating at temperatures as high as 400°C (750°F) to collect, transport, and store heat in CSP applications. It offers the high temperature stability necessary to avoid unacceptable fluid degradation at elevated operating temperatures.
Oil & Gas
Heat Recovery in Refining ─ Dow heat transfer fluids are used for heat recovery in refining operations where significant excess heat is created. They repurpose this waste energy to power other processes within a refinery. Unlike mineral oil, DOWTHERM AND SYLTHERM heat transfer fluids reach higher temperatures without degrading, scaling or corroding a unit or system. They can also increase heat transfer efficiency while maximizing energy savings. Dow offers a broad line of performance fluids to address a wide range of temperatures and fluid life requirements.
Pharmaceutical Batch Processing ─ SYLTHERM XLT silicone fluid is one of the leading products used in pharmaceutical batch processing. The fluid operates from -100°C (-150°F) up to 260°C (500°F), has essentially no odor, is very low in acute oral toxicity, and is not listed as reportable in the U.S. under SARA Title III, Section 3131. DOWTHERM J synthetic organic fluid offers high temperature performance. The fluid can be used in liquid phase as low as -80°C (-110°F) and up to 315°C (600°F). It is the fluid of choice for the most demanding single fluid heating and cooling applications. DOWTHERM 4000 inhibited ethylene glycol-based fluid offers low temperature pumpability down to -28.9°C (-20°F) and high temperature operation up to 175°C (350°F); DOWFROST HD inhibited propylene glycol-based fluid offers the advantage of lower toxicity with a recommended operating range from -45°C (-50°F) to 160°C (325°F).
Other Applications ─ For applications where regulatory compliance is a concern, DOWFROST inhibited propylene glycol-based fluid has a recommended operating range of -45°C (-50°F) to 120°C (250°F). The ingredients in DOWFROST fluid are considered safe by the U.S. FDA food additive regulations for use in applications where incidental contact with food, potable water or other products for human consumption is possible.1
Nylon/Polyester ─ DOWTHERM and SYLTHERM heat transfer fluids are thermally stable when used within their recommended operating temperature ranges and a variety of fluid options are available to help meet specific processing requirements. The fluids can provide the desired level of heating without charring and degradation that can reduce heat transfer efficiency, require frequent fluid addition, shorten fluid life, and result in system downtime for cleanout, maintenance or repairs. Because properly used Dow fluids will not foul heat transfer surfaces, the consistent, even heating required in fiber drawing processes can be maintained.
PET ─ DOWTHERM and SYLTHERM heat transfer fluids are used to maintain the precise and uniform temperature control needed to help achieve product quality and enhanced physical properties in chip production and blow molding operations. Material reservoirs, molding machines and extruders can all be maintained at specific temperatures by circulating heat transfer fluid at a controlled rate. The processing temperature required usually determines which is preferred.