Are you still saving... or are you already investing?
It is unbelievable, but true: No matter whether you had bought a barrel of oil eleven years ago, five years ago, one year ago, six months ago or three months ago: You would always have outperformed the DAX, both on a euro basis (blue curve) and on a dollar basis (green curve).
Source: comdirect.de, Oil price-DAX comparison
Ten years ago, on 12.04.2001, a barrel of Brent Crude Oil cost 27.01$ and the Euro 0.8882$, so the barrel cost 30.41€. Yesterday, 11.04.2011, the barrel cost 126.18 $ and the Euro 1.4478 $, so the barrel cost 87.15€, an increase of 187%. To achieve the same result by saving, you would have had to invest the money for ten years at 11.1% - including compound interest! So the average inflation of oil in euros within the last ten years was 11.1%.
What each of us expects in the coming years is of course a result of our personal assessment of the situation. But the fact is that the global money supply has grown faster than the available oil supply in recent years and that the demand for oil is constantly increasing. Based on this, everyone should think twice before investing their money in efficient heating technology, because the return could continue to rise and will remain tax-free for the foreseeable future.
How do investments in efficient heating systems pay off?
The price of the heating does not play the decisive role
"What will it cost me to renew my heating system?" is a question you will certainly often be asked. However, it is often overlooked that a heating system is a long-term investment whose operating costs must be included in the calculation.
Example: An atmospheric boiler with 24 kW is replaced by a new 20 kW condensing boiler, which costs 7,500€ including the adaptation of the flue gas system. How long does it take to earn back the investment? If the boiler is not oversized, it should run for about 2,000 h per year at nominal output, so that 40,000 kWh or about 4,000 m³ of gas are burnt in the 20 kW boiler. At a price of about 0.65€ per m³, the gas would currently cost about 2,600€ per year. If one had reduced the gas consumption by 15% by replacing the boiler, one would have previously spent 3,060€ per year on gas. Thus, with the new boiler, you save €460 per year and it takes a little over 16 years to recoup the investment of €7,500.
- Amortisation rendeMIX
"Is it worth it?" many will surely ask. It is easy to forget that the new heating system does not save money, but fuel, which can become much more expensive in the future. With an annual price increase of 11%, for example, the saving of 460€ becomes 698€ in the fifth year, 1,177€ in the tenth year and 3,341€ in the twentieth year. Thus, the investment in the heating system is not paid off after 16 years, but already after ten years. And after twenty years, the total saving is not 9,200€, but 29,533€, so that after deducting the investment, not only 1,700€, but 22,033€ remain.
It is therefore obvious that the consumption of the heating system and future energy prices play the decisive role in the question of how sensible an investment in efficient heating technology really is.
Does the reduced consumption through rendeMIX outweigh its costs?
Let us further assume that by using a rendeMIX heat distribution system, the consumption of the above-mentioned condensing boiler would be reduced by another 8%, which is demonstrably no exaggeration. Thus, the costs in the first year would drop from 2,600€ to 2,392€, which corresponds to an additional saving of 208€ in the first year. This amount increases to 316€ in the fifth year, 532€ in the tenth and 1,511€ in the twentieth, assuming an annual inflation of 11%.
If a suitable rendeMIX multi-way mixing manifold costs €1,415 including installation, it would be paid for after just over five years. However, if one takes into account that the use of the rendeMIX multi-way mixing manifold eliminates the need for a hydraulic separator including controller module, a manifold as well as a pump and a mixer group, there are often no additional costs at all. Thus the entire heating system has paid for itself not only after ten years, but already after eight. And the total surplus of the investment after twenty years rises from 29,533€ to 35,387€. Seen in this light, the investment in a rendeMIX heat distribution system is not only paid off quickly, but also shortens the amortisation of the entire heating system.
Pro tip: Parallel or one behind the other?
What to do with several buffer storage tanks?
Systems are increasingly being equipped with buffer storage tanks, whether for heat pumps, wood boilers, CHP units or solar systems. It is not uncommon for the necessary storage volume to have to be divided among several smaller tanks because only these fit through the doors or stairwells. This raises the question of whether a parallel or back-to-back connection of buffer storage tanks is the better solution. As usually in life, the appropriate answer is: "It all depends."
Basically, our customers, readers and interested parties know that the efficiency of heat storage depends to a large extent on the stratification in the storage tank. And for stratification, a slim and tall storage tank is certainly better than a small and wide one with a large diameter.
Image 1
Figure 1 shows a buffer tank with three connections in parallel. It is quite obvious that with the parallel connection the total volume is distributed over several tanks via the cross-section. It can also be seen that the number of tanks can be increased as desired. The important thing with the parallel connection is that
- all containers are at the same height
- all connection ports (1) to (3) belonging to each other are at the same height
- the connecting lines run exactly horizontally
- the connecting lines are as short as possible, have no bends and large cross-sections
- the connection lines always open vertically into the connection lines
Picture 2
Figure 2 shows the parallel connection of buffers with four connections, for which the same conditions apply. Again, it is important to note that one can choose the number of containers independently of the number of connections, which is a great advantage of the parallel connection.
Image 3
Figure 3, on the other hand, shows the series connection of two buffer tanks. It is clearly visible that in this case the total volume is distributed over the height of several tanks. While in the parallel connection all tanks contain the same temperatures, in the series connection there are tanks with different temperatures. Also, the number of tanks in series corresponds to the number of storage zones, which is directly related to the number of connections. In Figure 4, for example, three tanks are connected in series, which corresponds to a buffer with four connections (1) to (4). For stratification in the buffer, connecting them one behind the other is certainly advantageous. Also, the containers do not have to be at the same height and the connecting lines do not have to be horizontal, straight or of particularly large cross-section. So all in all, only advantages?
Picture 4
Picture 5
No, because there is also a serious disadvantage of the series connection: No gravity compensation is possible between the individual containers (buffer zones)! Fig. 5 explains what this means: If, for example, a buffer with an internal solar heat exchanger and one with an internal DHW coil are to be combined, this can only be achieved via gravity compensation and thus parallel connection. With a series connection, the solar heat would never reach the DHW in summer. If, on the other hand, a solar loading station and a fresh water station are used, as shown in Fig. 6, a series connection can be used, as the stations ensure the heat transport between the individual tanks with their pumps. However, it must be ensured that the loading station also loads the upper or hotter buffer in summer, i.e. that it contains a stratified charging module (differential temperature switchover valve). If this is ensured, the series connection can fully exploit its advantages over the parallel connection.
Picture 6