Ceramic heat storage: heat where it belongs.

Every boiler's hidden problem

A boiler can only transfer part of the flame's energy to the water immediately — the rest leaves the plant as flue-gas heat or is lost in cooling and restart phases. No standard measurement sees this energy, because inspections only measure while the burner runs. It still shows on the gas bill — year after year.

The reason lies in the cycling: heat demand moves across the day, but the burner only knows on and off. Every start costs a pre-purge, every shutdown a cool-down.

Why the burner cycles at all

The boiler water temperature swings between two switching points. When it drops below the lower one the burner fires; when it rises above the upper one it shuts off. This switching differential is inherent to the design and cannot be tuned away — it determines how often the burner starts during a day.

The solution: pure physics

• ■Solid ceramic elements (rated for applications up to 1,650 °C) are positioned in the flame tube in one day — no structural work, no electronics, no change to burner or controls.
• ■In operation the ceramic glows white. Its emissivity of ~0.95 (boiler steel: 0.25) radiates heat directly onto the water-side surfaces — ~18 percent more heat transfer to the water side (GWI simulation).
• ■As a heat store the ceramics keep working while the burner rests or modulates: the boiler holds its temperature far longer, the burner restarts later or runs at a lower stage.

The real lever: the glowing heat store

The ceramics store flame energy the boiler itself cannot absorb and release it as soon as the burner rests. When the burner switches off, the glowing ceramics keep the boiler warm far longer — it needs to restart much later. When the burner modulates, the larger heat-transfer surface lets it run at a lower stage for the same heat demand — like a car doing 80 km/h in fifth gear instead of fourth: same speed, less fuel. In the latest hospital measurement (July 2026), burner runtime fell from 205 to 105 minutes for the same heat delivered. And on plants whose flue path stays open during pauses, the glowing ceramics additionally prevent the chimney from cooling the boiler down.

The TU Clausthal report shows that a ceramic mass of only about one percent of the water in the boiler is enough for this — a small installation with a large effect, because the ceramic glows at around 1,000 degrees while the water varies by only a few degrees.

This becomes measurable in the boiler's cycling: the burner starts less often and runs for shorter spells — at exactly the same heat delivered.

Why ceramic and not steel?

A heat store could in theory also be built from steel. High-temperature ceramic beats it on two counts: it can be heated much higher and therefore stores more energy, and — unlike heat-resistant steel — it withstands the sulphur compounds produced by oil firing. That is why we use solid ceramic elements, not metal.

Our quality test shows how robust the material is: every batch is quenched 30 times from white heat — above 1,000 °C — in cold water, without any change to its properties. This is made possible by the firing process, which runs at 1,500–1,800 °C over several days — the basis of the longevity our installations have proven since 2016.

Technical data — INTENSATEC enSAVERtwo

• ■Application limit: 1,650 °C
• ■Bulk density: 2.5 g/cm³
• ■Cold crushing strength: 70 N/mm²
• ■Thermal conductivity: 1.71–1.75 W/mK
• ■Thermal shock resistance: very good

We present the full technical data sheet in the technical discussion.

For which plants?

• ■Warm-water, hot-water, steam and thermal-oil boilers from approx. 150 kW to 30 MW.
• ■Fuels: natural gas and oil. Requirement: horizontal forced-draught burner.
• ■Maintenance-free for life; transferable into a new boiler.
• ■Older boilers often return below emission limits thanks to cleaner flue gas — an expensive replacement often becomes unnecessary.

These are solid ceramic heat-storage elements — not a coating and not electronics. Nothing to wear out, calibrate or maintain.

The black box in the boiler room

Before any promise of a saving comes a question that is rarely asked: how do you actually know what your boiler consumes today? The next three sections answer it. If you would rather listen than read, here is the whole train of thought in a few minutes.

How do you actually know what your boiler consumes?

Before we talk about proving the savings, an honest inventory is worthwhile: 99 percent of all boiler plants have no heat meter directly at the boiler. Operators know to the cent how much gas they purchased — the invoices are on file. How much usable heat the boiler produced from that gas has never been measured — not since its first day of operation.

A picture makes it tangible: imagine a car whose glovebox is full of fuel receipts — but which has no odometer. You can state exactly what you refuelled in any given year. What that car consumes per hundred kilometres is still impossible to say — the second half of the equation is simply missing. Your boiler has been running exactly like this for years: purchases fully documented, output a black box.

Existing sub-meters change little. In large buildings the boiler water flows via a hydraulic separator onto a distribution manifold with many circuits — pool area, administration, block C, therapy centre. Heat meters sit where individual buildings are billed, typically on seven out of ten circuits. Added up, they capture 70 to 80 percent of the distributed heat; the rest passes them by. The one meter that would truly answer the question — directly at the boiler outlet, upstream of separator and return-temperature control — is missing almost everywhere.

Why the gas bill is ruled out as proof

The obvious idea goes: install the ceramics, run the plant for a year, then compare gas bills. This approach fails on the scatter of everyday operations. A site's heat demand varies by 20 percent and more from year to year — milder or harsher winters, higher or lower occupancy, changed production hours, an additional building connected. Within that scatter, a 13 percent saving simply disappears.

A real case shows how much: one year after installation, a customer reported roughly 20 percent higher consumption and blamed the ceramics. After long questioning the cause emerged — he had meanwhile connected another administration building with 200 workplaces to the same heating plant. The invoice only documents how much gas was bought; it is silent about the reasons.

That is why we put this topic on the table in every first consultation, before you sign: you should know in advance what can be proven afterwards — and by which method.

The solution: we install the odometer — temporarily

The before-and-after measurement, following the method developed together with TÜV, gives your plant — for the duration of the measurement — exactly what it always lacked: complete recording of what goes in and what comes out. Measurement takes place under controlled identical conditions — same plant, same instruments, comparable load, one day apart: once without ceramics, once with. To stay in the picture: same route, same driver, same speed — once without, once with the technology.

Because both runs use the same instruments, every instrument tolerance drops out of the calculation — what is captured is the difference. On top of the result we apply a five percent safety margin. This difference is the reliable figure. In the latest hospital measurement, burner runtime fell from 205 to 105 minutes for the same heat delivered.

And this figure holds permanently, because the ceramics work by the same physical laws at every burner start — in a warm year as in a cold one, at full as at half occupancy. Your absolute consumption will continue to vary with weather and utilisation; the percentage advantage of the ceramics remains.