Most boiler enquiries start with a capacity figure. That is the second question. The first is what the boiler should carry heat in, because steam, hot water, superheated water and thermal oil behave differently, fail differently, and cost different amounts to run.
Get the heat carrier wrong and no amount of correct sizing rescues the installation. This page sets out how the choice is actually made, and compares the Ekotek series Hi-Best supplies in Saudi Arabia.
The decision that comes before capacity
Four heat carriers cover almost every industrial requirement, and the process usually decides which one for you.
Steam carries a large amount of energy per kilogram and gives it up at a constant temperature, which is why it suits sterilising, cooking, pressing, drying and any process that needs a fixed temperature held precisely. The cost is a pressure vessel, feedwater treatment, blowdown and a competent operator.
Hot water is simpler and safer, and covers space heating and process water below about 100°C. Below that ceiling there is rarely a reason to generate steam.
Superheated water is pressurised so it can exceed 100°C without boiling. It gives higher process temperatures than hot water without the operating burden of a steam plant, which is why it suits industrial heating loads that sit awkwardly between the two.
Thermal oil reaches high temperature at low pressure, which is its whole argument. Water at 300°C needs roughly 85 bar. Thermal oil reaches the same temperature at close to atmospheric pressure, so the safety case, the vessel and the maintenance all get easier. It also does not scale, corrode or need conditioning.
The five series compared
| Series | Heat carrier | Output | Working pressure | Temperature | Heat capacity | Fuel | Design |
|---|---|---|---|---|---|---|---|
| Storm | High pressure steam | 175 to 32,000 kg/h | 3 to 16 bar | – | 125,000 to 20,000,000 kcal/h | Gas, liquid or dual fuel | Fire tube Scotch, 3 pass |
| Performance | High pressure steam | 200 to 4,000 kg/h | 3 to 16 bar | – | 125,000 to 2,500,000 kcal/h | Gas, liquid or dual fuel | Counter pressure, 2 pass |
| Atlas | Superheated water | – | 2 to 16 bar | up to 200°C | 100,000 to 20,000,000 kcal/h | Liquid fuel | High pressure, nitrogen balance tank |
| Atom | Hot water | – | – | – | 80,000 to 2,500,000 kcal/h | Gas or liquid | Reverse pressure, turbulators |
| Electro | Thermal oil, electric | – | Low pressure | 60 to 320°C | 100,000 to 5,000,000 kcal/h | Electric, 230V or 380V | Coil type, no flue |
Figures are manufacturer data for the series range, not for a single unit. The model within each series is selected against your calculated duty. A fired thermal oil heater is also available for high process temperatures where electricity is not the preferred energy source.
Steam: Storm or Performance
Both produce steam between 3 and 16 bar, so pressure does not separate them. Capacity and duty pattern do.
The Storm Series holds a large water and steam volume and runs to 32,000 kg/h. That volume is the point: it absorbs sudden demand without the pressure collapsing. If your plant has surges, several large users starting together, or a batch process that draws hard for short periods, this is the one that copes.
The Performance Series is a counter pressure design that deliberately keeps water volume small and steam volume large. Less water to heat means steam is available faster from cold, and the higher heating surface produces drier steam. It runs to 4,000 kg/h.
The short version: steady or surging demand at scale points to Storm. Fast start from cold, drier steam and moderate capacity points to Performance. Where daily start-up time drives the operation, that requirement can decide the boiler on its own.
Hot water: Atom or Atlas
The dividing line is temperature, not capacity.
The Atom Series is a conventional hot water boiler to 2,500,000 kcal/h, using reverse pressure combustion so unburnt fuel meets the flame a second time. It suits building heating, hotel and compound hot water, and process water below 100°C.
The Atlas Series runs pressurised to 16 bar and up to 200°C, to 20,000,000 kcal/h. Use it where the process needs more than water can give at atmospheric pressure but a steam plant is not justified. Note it is liquid fuel, so confirm fuel supply before specifying.
Thermal oil, and when it beats steam
Above roughly 180°C, steam starts to lose the argument. Holding water at that temperature needs serious pressure, and pressure means thicker vessels, more inspection and more risk. Thermal oil reaches 320°C at low pressure.
The Electro Series is electrically heated, so there is no burner, no flue and no combustion air. That matters where a flue is impractical, fuel storage is not permitted, or the site simply has no gas. It reaches 320°C to 5,000,000 kcal/h.
The trade is running cost. Electricity per unit of heat is usually dearer than gas, so electric thermal oil wins on installation constraints and emissions rather than on fuel bills. Where those constraints do not apply and high temperature is needed, a fired thermal oil heater covers the same temperature range at larger capacity.
Two things to plan for with any thermal oil system: an expansion tank sized for the oil volume, and the fact that thermal oil is a consumable with a service life, not a permanent fill.
Fuel decides more than you expect
Gas availability is not uniform across Saudi industrial areas, and it is worth confirming at the plot rather than assuming from the district.
Storm, Performance and Atom accept gas, liquid or dual fuel. Atlas is liquid fired. Electro needs only an electrical supply.
Where supply is uncertain, or the process cannot stop if supply is interrupted, dual fuel is usually worth its extra cost. A plant specified for natural gas on a site with no connection ends up on temporary fuel for the life of the installation, which is an expensive way to find out.
A short decision path
- What temperature does the process actually need at the point of use?
- Under 100°C: hot water. Atom.
- 100 to 200°C without a steam plant: superheated water. Atlas.
- Steam required as the medium: Storm for capacity and surge, Performance for fast start and drier steam.
- Above 200°C: thermal oil. Electro where combustion is impractical, fired where it is not.
- Now confirm the fuel available on site, and only then calculate capacity.
Capacity comes last on purpose. Sizing before the carrier and fuel are settled is how plants end up with equipment that works perfectly and does the wrong job. Our industrial boiler sizing guide sets out the calculation itself.
What to send us
- The process the boiler serves, and the temperature it needs at the point of use
- Whether the load is steady, intermittent or surging, and when peaks occur
- Connected load item by item, if you have it
- Start-up requirement, and how fast the plant must be productive from cold
- Fuel actually available at the site: natural gas, diesel, LPG, or electric only
- Feedwater analysis, for any steam duty
- Plant room dimensions, including access for installation and future removal
- Whether this is a replacement or a new installation
Incomplete information is normal at first enquiry. We would rather start the conversation and fill the gaps than quote against assumptions.
Send your requirements and we will specify against them
Hi-Best has supplied and installed industrial boilers across Saudi Arabia since 1995. Call +966 54 433 2843 or request a quotation. You can also see the full industrial boiler range.