Single water heat pump for heating Air-water heat pump for heating

Morning...

After a lot of searching for a good heating system, we came across a heating engineer who offers the following option:
A brine-water ground source heat pump with 48 sqm surface collectors (laid out in 100 sqm garden area because they have to be spaced apart) for the heating system (138 sqm underfloor heating) and an air-water heat pump for the hot water demand.

Has anyone ever used such a combination?

The reason for this is that the ground source heat pump apparently reaches its limit for hot water preparation and works significantly less efficiently compared to an air-water heat pump. In addition, in summer the ground can regenerate and, if necessary, heat can be pumped from the house into the ground.

Compared to a pure brine-water heat pump, the whole thing is about 5000 euros cheaper, mainly due to the earthworks.

Best regards

Hello,

...after a lot of searching for a good heating system, we came across a heating engineer who offers the following variant:

How do you find the right heating system just by looking around? :confused:

...The reason is that the ground source heat pump apparently reaches its limit for hot water preparation and is significantly less efficient compared to an air-to-water heat pump.

You should quickly forget about that seller! The annual performance factor of a brine heat pump is always better than that of an air heat pump. There are physical reasons for this.
If the brine heat pump already reaches its performance limit just because of the little hot water, he must take a stronger one and adjust (expand) the source accordingly. Selling two devices of course makes more sales ;-)

...In addition, the ground can regenerate in summer and, if necessary, heat from the house can be pumped into the ground.

That is also possible when a brine heat pump provides the energy for heating and hot water! In summer, the energy share for heating is anyway eliminated, so the source can recover anyway.

...Compared to a pure brine-water heat pump, the whole thing is about 5000 euros cheaper, mainly due to the earthworks.

What exactly is a pure brine heat pump?
Whether a horizontal collector is even suitable here is probably only known to the seller ;-) Possibly, a trench collector of narrow or wide design is much better suited if you want (or can) avoid vertical drilling! In addition, considerable investment can be saved through personal contribution.
That this combo is cheaper than a single device probably has a significant catch ;-)

What figures were determined within the scope of the offer for:

Heating load, hot water power, annual energy demand for heating and hot water, extraction power and energy for the source of the brine heat pump?

Best regards

-How do you find the right heating system by looking around? :confused: = Inform yourself, read, talk to people who have different system types themselves such as district heating, gas/solar, air heat pump, ground source heat pump with surface collectors, deep drilling, spiral baskets and energy fence, partly in combination with photovoltaics or solar, pellet stove... Contacts with heating installers and house construction companies... just look around at what is available...

-You should quickly forget the salesperson! The annual performance factor of a brine heat pump is always better than that of an air heat pump. That has physical reasons.= According to manufacturer information and the local energy consultant, this is not the case; the brine-water pump was given or calculated with an annual performance factor of under 2.

-If the brine heat pump alone already reaches its performance limit just from the little hot water demand, a stronger one must be taken and the source adjusted (expanded) accordingly. Selling two devices naturally generates more revenue ;-)= The offer with 2 devices is cheaper than the offers with one device, according to the manufacturer (with whom I spoke on the phone) the pump itself is not the problem, but getting the energy from the ground to heat the hot water to 65 degrees, which is generally the case that the brine-water heat pump then no longer has an annual performance factor of 4 but 2.

-That works too, if a brine heat pump provides the energy for heating and hot water! In summer, the energy portion for heating is omitted anyway, so the source can recover. = The heat pump is then used for cooling.

-What is a pure brine heat pump? = Just a ground source heat pump.

-Whether a surface collector is suitable here is probably only known by the salesperson ;-) Possibly a trench collector of narrower or wider design is much better suited if one wants to avoid (can?) vertical drilling! Additionally, significant investment can be saved through own work. That this combo is cheaper than a single device probably has a significant catch ;-)= Deep drilling not possible due to protected water zone, also too expensive anyway (8000 euros), surface collectors would otherwise be 400 sqm instead of 100 sqm, own work is the laying of the collectors, but with a 6-day week, with wife and child, time is rather rare. Spiral baskets are not an option due to the soil conditions... Energy fence also not feasible due to a wall of the nature reserve and shady property boundaries...

What figures were determined in the offer for:

Heating load, hot water performance, annual energy demand for heating and hot water, extraction capacity and energy for the source of the brine heat pump?= I cannot say currently, it is on the planner’s desk.

Hello,

= Inform, read, ......just take a look around at everything available...

That then led to this result!

... According to the manufacturer's specifications and the energy consultant on site, this is not the case, the brine-water pump was specified or calculated with a seasonal performance factor below 2.

Anyone who lets themselves be sold a brine heat pump under such conditions is to blame themselves. Throw the energy consultant in with it right away!

... Offer with 2 devices is cheaper than the offers with one device, ...

Someone obviously really wants to get rid of something ;-)

...According to the manufacturer (with whom I talked), the pump is not the problem, but getting energy from the ground...

Then the source is incorrectly designed!

...to heat the hot water to 65 degrees, but it's generally the case that the brine-water heat pump then no longer has a seasonal performance factor of 4 but 2

Who uses a heat pump with 65°C flow temperature? They should get a slap on the wrist.
Besides, what seasonal performance factor would an air heat pump have then? ;-)

...Energy fence also not feasible due to a wall of the nature reserve and shady property boundaries..

That makes even less sense, since I assume the building is not located in sunny Spain!

...I can't say at the moment, it's on the planner's desk

The absolutely necessary numbers are not known, but the seller already knows in advance which manufacturer, devices and how large the surface collector must be :confused: My sincere condolences to this professional competence! The whole thing will be a money pit!

Best regards

can only agree with €uro on that. and he is the energy pope here ;-D

Just kidding aside. I am just a homeowner too, not an expert. But all alarm bells must be ringing for you.
If the planner designs the source properly, you’ll get a device way cheaper. Because the source of geothermal energy has to be developed anyway. Plus the air heat pump. It’s crazy what some people come up with. And the story with the hot water I find funny. First of all, the supply temperature should be around 32°C. And the hot water demand is super low compared to the heating demand. I once heard something like 5% or so. But €uro is also the better contact for that. Your heating system simply must not reach its limits.

The absolutely necessary numbers are not known, but the seller already knows in advance which manufacturer, devices, and how big the flat collector needs to be :confused: My sincere condolences for this technical expertise! The whole thing will be a money pit!

v.g.

I did not say that, I said that I do not have the numbers because they are with the planner, who in turn was in contact with the heating installers, or they were with him so that I can get the numbers from him...