ᐅ Building Services for a New 230 sqm Urban Villa

Well, it’s hard to find companies that are willing to do quality work... why not ask the manufacturer if this is a strict requirement? That way, you’ll have a better idea of whom you can trust more.

MKoni schrieb:
Hello, I inquired today about the buffer tank, and it is absolutely necessary. Regardless of the manufacturer—I have five offers from four different manufacturers, all including a buffer tank—it always costs around 500 euros net.
It is essential for operating the heat pump properly, so it does not go abruptly from full operation down to zero. It’s like a car that doesn’t brake before hitting a wall but drives straight into it. The heat pump can run without it, but that involves risks and significantly shortens its service life. It’s not a preference of heating system installers but a requirement from the manufacturers.

Hit me, but how can you afford such a house if you write so disorganized? Or, to put it another way: What am I doing wrong?

Great post – how is one related to the other?

Besides, it’s quite easy to read, isn’t it..?

Sometimes such answers really leave you speechless.....

@Bieber, you are right, I’m also considering whether to do it that way, but we still want to take two vacations a year with our kids, keep driving our T5 Multivan and the S Max as our two cars, and maintain the two BMW motorcycles. The hobbies of the four girls—dancing, horseback riding, piano... With all that, you have to make compromises with the house, so it will just be a bit smaller...

But to the point, manufacturer’s statement:
With a buffer tank, the primary question is: Are the heating circuits controlled? You can connect directly to the underfloor heating if no more than 20% (bedrooms) of the circuits are controlled. Since underfloor heating is a very slow-reacting system, in new buildings, lockout periods can easily be tolerated without a noticeable change in room temperature. If the heating circuits are controlled, it is essential to install a buffer tank sized around 30-50 liters (8-13 gallons) per kW of heating capacity.

If no heating buffer is present and the heat pump’s heating curve is set higher than the room control curve, the heat pump’s temperature difference between supply and return can exceed 30°C (54°F), which in the worst case can cause a high-pressure fault. With a buffer tank, the heat pump maintains a constant temperature difference of 5°C (9°F) between supply and return, which represents the optimal operating point of the refrigeration cycle.

And

A buffer tank is only necessary for underfloor heating if a 100% individual room control system is installed. This is required according to the energy-saving ordinance (EnEV). “Clever” heat pump installers avoid this 100% individual room control by continuously circulating water through some (few) heating circuits. This means that only about 50% of the heating circuits control the room temperature. For air-source heat pumps, it must also be considered that without a buffer tank, the defrost capacity (e.g., during defrost operation via refrigerant cycle reversal) must be drawn from the underfloor heating.

The ideal solution is the use of a modulating heat pump that adjusts its output according to the outdoor temperature and the actual demand, including during defrost operation. This means that omitting a buffer tank requires an installer who can accurately assess the situation. Systems without a buffer simply require more experience with heat pumps.

Omitting the buffer tank can lead to higher efficiency if done correctly.

You should mention that the text is not your own.

By the way, individual room control is really nonsense – I’m skipping it, as well as the buffer tank.

Modulating heat pump? As far as I know, that doesn’t exist for ground source (brine) heat pumps... but I’m not entirely sure.