Drinking water reservoir? If already - then already!
The new rTANK
Until a few years ago, drinking water storage tanks were considered the solution par excellence for heating drinking water, and they are still widely used in the private sector today. And who is surprised? After all, they offer a comparatively high level of comfort with little technical effort and are available at a reasonable price.
With the advent of solar systems, however, it became necessary to reduce the return temperatures to the heating system as low as possible. And at about the same time, the legionella issue arose. Both spoke in favour of instantaneous water heater systems, the hygiene storage tank with corrugated tube heat exchanger and the fresh water station. But is this additional expense really always justified and aren't there other disadvantages?
Most drinking water storage tanks are enamelled steel tanks. Enamel is a glass-like coating that is never free of cracks. Therefore, the installation of sacrificial anodes for corrosion protection is essential. These must be maintained regularly, which is usually omitted or even fails if the thread of the anode is already corroded as well. The service life of the anode depends on the water quality as well as on the quality of the enamel layer: the more cracks there are, the faster the anode dissolves. An annual check is therefore absolutely necessary. To be fair, these costs must be added to the purchase price to make it comparable.
If, however, this control is not carried out, a disastrous mixture of corrosion residues and lime forms in the storage tank. Lime-containing water is usually also corrosive, as the lime is only dissolved in the water via acid. If the lime precipitates during heating, the pH value of the water drops - this becomes acidic and attacks the steel.
But that's not all: the enamel layer is also an obstacle to heat transfer, as can be easily determined by comparing the area performance of the heat exchangers. It also doubles the weight of the storage tank and makes it very sensitive to impacts, which happen particularly easily during transport.
So if you want to avoid these disadvantages, heating drinking water in a stainless steel storage tank is the way to go: It is
- Cost-effective due to significantly lower maintenance costs and longer service life
- Hygienically flawless due to clean and smooth surfaces of a material used in medical technology and the food industry
- Much less critical against calcification than instantaneous water heaters and much easier to decalcify (enamelled storage tanks are practically impossible to decalcify).
- Much more powerful than comparable enamel storage tanks and can be operated in the condensing range and with heat pumps
For these reasons, we have decided to work with the rTANK to offer a series of bivalent drinking water storage tanks with 200, 300 and 400 l capacity, which combine all of the advantages mentioned. Bivalent because you also benefit from the even larger surface area of the heat exchangers in monovalent operation. And together with our RTB-Depending on the application, return temperatures suitable for condensing boilers and even solar energy can be achieved here with the help of the special valves.
Conclusion: With rTANK drinking water storage tanks, you avoid the disadvantages generally associated with drinking water storage tanks without foregoing the long-known advantages of drinking water storage heating - and they are not even more expensive, when you get right down to it. So with a clear conscience: If already - then already!
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