Using a dry cooler as a heat source
Ambitions for sustainability lean heavily on the heat pump. The device makes no heat of its own; it moves heat efficiently, the way a pump does. To do that it needs not only electricity, but a heat source.
A heat source can be almost anything — the ground, groundwater, even low-temperature geothermal. Many other systems use air as their source.
Air is an extremely convenient heat source. It renews itself, and for most of the year it sits at a perfectly acceptable temperature. But at the moment you need heat most, it is of course cold — so exactly when the heat pump has to deliver its greatest heat load, its efficiency is at its worst. Air can still serve well as a source: as long as the air temperature stays above 5 degrees it is a very favourable one. Cooling the air condenses water out of it, and that condensing water delivers extra energy for the source to use.
And when it is genuinely cold?
In (very) cold conditions, freezing on the air-side surface of the dry cooler cannot be avoided. It happens mainly in cold spells with a lot of moisture in the air: cooling the air condenses that moisture out, and it then freezes against the icy surface of the dry cooler. Briefly this gives a little extra heat, since freezing carries a great deal of (latent) energy with it.
That freezing advantage is very short-lived. A thin layer of ice forms on the dry cooler, and with it the cooler loses its ability to transfer heat. This is the great challenge of dry cooler heat sources — so is there a solution?
The ice battery — a solution both for regeneration and as a source
The ice battery is designed to exploit freezing completely. Where the efficiency and effectiveness of dry coolers collapse in winter, an ice battery is a constant source of energy.
So the dry cooler and the ice battery reinforce one another. The moment the dry cooler freezes over and stops working, the ice battery takes over as the source. In warmer periods — during the day, or later in the week — the dry cooler helps melt the ice battery again. An ideal combination for security of supply and optimal performance.
To find out more about heat pump sources, whether air or ice, get in touch with De Korne. Your specialist in industrial heat.
