How the model codes work
Every product in the range carries an LM prefix followed by a number that identifies the family — LM-1, LM-4, LM-8, LM-16. A letter or letters after the number identify a variant within that family, which usually marks a difference in material compatibility, temperature range or additive approach rather than a difference in the base chemistry.
Three sub-ranges use a different pattern. LMH, LMT and LMZ are additives rather than coolants: they are dosed into an existing fluid or water system. LM-XL and LM-XR are phase-change materials, which store thermal energy rather than circulating through a loop.
The practical consequence: the code tells you which family you are dealing with, and the family tells you the chemistry class and its general behaviour. It does not tell you the temperature range or the compatible metals — those are set per model, and they are what a specification has to confirm.
Product families at a glance
| Code | What it is | Typical range |
|---|---|---|
| LM-1, LM-1L | Alcohol-based coolants for low-temperature circulation. The L variant extends metal compatibility. | −100 °C to ambient |
| LM-3 series | Alcohol coolants formulated for particular duties, including food-industry secondary refrigeration. | −80 °C to ambient |
| LM-4 series | Glycol-type (modified-diol) coolants. The widest family, with variants for aluminium, elevated temperature and data-centre duty. | −35 °C to +150 °C, model-dependent |
| LM-4A series | Diol coolants tailored to specific applications and material sets. | −20 °C to +100 °C, model-dependent |
| LM-4B | Food-processing secondary coolant, formulated around food-industry refrigeration. | −20 °C to +95 °C |
| LM-5 | Mixed-alcohol industrial coolant. | −50 °C to ambient |
| LM-6 series | Ultra-low-temperature anhydrous coolants for dry, closed loops. | −130 °C to +30 °C, model-dependent |
| LM-7 | Wide-temperature alkane coolant, anhydrous. | −70 °C to +150 °C |
| LM-8 series | Non-combustible salt-based coolants. No flash point. | −50 °C to +100 °C, model-dependent |
| LM-8A | Inorganic salt secondary refrigerant, supplied ready to use. | −40 °C to +100 °C |
| LM-9 series | Wide-range organic heat transfer fluids. | −75 °C to +270 °C, model-dependent |
| LM-11 series | Anhydrous alkane fluids for systems where water must be excluded. | −100 °C to +100 °C, model-dependent |
| LM-14 series | Fluorinated fluids for electrical insulation and precision temperature control. | −110 °C to +135 °C, model-dependent |
| LM-15 series | Silicone-based heat transfer fluids for high-temperature duty. | −70 °C to +200 °C, model-dependent |
| LM-16 series | High-temperature thermal oils and synthetic fluids. | up to +350 °C on selected models |
| LM-17 series | Dielectric fluids for single-phase immersion cooling of server hardware. | −30 °C to +100 °C, model-dependent |
| LMH | Corrosion inhibitor added to brine systems. An additive, not a coolant. | system-specific programme |
| LMT series | Corrosion and scale inhibitors for circulating cooling water. An additive. | system-specific programme |
| LMZ series | Performance additives for existing alcohol-based coolant charges. | base-fluid dependent |
| LM-XL series | Phase-change materials that store cold. Not circulating fluids. | nominal grades −24 °C to −2 °C |
| LM-XR series | Phase-change materials that store heat. Not circulating fluids. | phase-change grades +7 °C to +55.5 °C |
Ranges are reference values for the family. The exact model, concentration and current technical data sheet govern any application.
Cooling terms, in plain language
- Secondary coolant
- The fluid that circulates through the process-side loop and carries heat to or from a heat exchanger. It does not change phase in normal operation. Also called a secondary refrigerant, a heat transfer fluid or, in older plants, a brine. Thermal fluid is the usual term for the same role in high-temperature process heating.
- Refrigerant
- The fluid in the compressor circuit. It changes phase — evaporating and condensing — to move heat. A secondary coolant carries heat to and from that circuit.
- Brine
- A salt solution used as a secondary coolant, historically calcium chloride or sodium chloride. Effective thermally, and aggressive to metals unless inhibited.
- Freeze point
- The temperature at which ice crystals first form and the fluid becomes slushy. The loop still circulates below it, with ice crystals in suspension.
- Burst point
- The temperature at which freezing expansion is sufficient to split pipework. It is lower than the freeze point, and it is reached at a lower concentration.
- Conductivity
- A measure of how well the fluid carries electric current, which in an aqueous coolant reflects its dissolved ionic content. Low conductivity matters where fluid sits close to live electronics.
- TAN (total acid number)
- A measure of acidity in a heat transfer fluid, used mainly for thermal oils. What matters is the rate of change across readings, not a single value.
- Reserve alkalinity
- The fluid's capacity to neutralise acid before the pH itself moves. It falls before pH does, which makes it an earlier warning of inhibitor depletion.
- Inhibitor package
- The additives that protect wetted metals from corrosion: film-forming agents, buffers, biocides and stabilisers, formulated to work together at a defined concentration.
- Anhydrous
- Containing no water. Anhydrous coolants are specified for loops where water is a contaminant rather than a diluent, and they need dry, closed commissioning.
- Miscible
- Capable of mixing with water to form a single phase. Water-miscible coolants are diluted with water; water-insoluble ones are not, and a spill of one is not diluted by adding water.
- Direct-to-chip (cold plate)
- A cooling architecture where fluid passes through a plate mounted on the processor. The fluid stays inside a closed loop and does not contact the electronics.
- Single-phase immersion
- A cooling architecture where server hardware is submerged in a dielectric fluid that does not boil. Distinct from two-phase immersion, where the fluid boils and condenses.
- Phase-change material (PCM)
- A material that stores and releases thermal energy as it changes phase, at a defined transition temperature. A storage medium, not a circulating coolant.
- Latent heat
- The energy absorbed or released by a phase change at constant temperature, measured in kJ/kg. Higher latent heat means more storage per kilogram of material.
- Concentration (wt% / vol%)
- The proportion of coolant in a diluted charge, expressed by weight or by volume. The two give different numbers for the same charge, and mixing them is a common source of confusion.