ᐅ Efficiency of Heliotherm Flat Plate Collectors

Hello everyone,

we have installed twice the collector area compared to the living area.

Regards
Muxel

With a ground source heat pump combined with a Heliotherm heating system? If yes, isn’t the standard price usually calculated at about 1.5 times the base cost, and did you have to pay more because of that?

@Carsten-le There are maintenance costs because the amount of coolant exceeds a certain threshold, which means regular maintenance is required. The cost depends on the company and your negotiation skills (there are several HVAC companies authorized to do this). Otherwise, the operation is quite straightforward (-> physics...).

If the surface area is too small, it will overcool excessively. The first downside is, of course, reduced efficiency – although direct expansion systems can still operate reasonably well at quite low temperatures – but then the surface (or rather the volume) also freezes (underground!). This causes ground movement (water expands again below 4°C (39°F)) and can raise the ground by several centimeters (the colder it is, the more it lifts). It also affects vegetation. For example, grass tends to grow poorly for quite a long time in spring.
With boreholes that are too shallow, usually only efficiency decreases.

I need to take another look at the coolant loss (that’s correct, right?). I can’t imagine that anything would need to be refilled in the medium term, or would it? With this technology, I would estimate about twice the living area anyway, so there shouldn’t be any problems, right?

It’s not about refrigerant loss; it’s about the legal requirement to have the system’s tightness checked. Just search, for example, “direct evaporator tightness test EU regulations” to find more information. Read up on it a bit. The regulations have become somewhat more complex recently (conversion to CO2 equivalent, etc.), but I’m quite sure that for the amounts of refrigerant used in direct evaporators, a regular inspection remains mandatory.

In principle, a small amount of refrigerant is always lost over time; it’s probably impossible to achieve a completely leak-free system. Refilling after who-knows-how-many years doesn’t cost that much.

I have read a bit about the mandatory leak-tightness test, but I haven’t found anyone who actually has it done annually – could it be just an assumption that this test is required? Or is it true that this test is not necessary for all heat pumps, as I have read.

Can you ask Saruss how much refrigerant is approximately used or contained in a heat pump with a direct expansion system?