ᐅ Combination of air-to-water heat pump + solar thermal system + stove, or stove and air-to-water heat pump only
Created on: 2 Feb 2016 22:33
N
Newbie123
Hello forum,
I am currently planning the construction of a new KfW40 single-family house.
The expert’s calculation resulted in the following (summary):
Heated building volume = 532 cubic meters
Usable floor area = 170 square meters
Qp-new building = 29 kWh/(sqm per year)
The construction company’s offer includes the following technology
(where KfW was only calculated with the heat pump):
Novelan heat pump LAD 5 (air-to-water heat pump)
Compact Station Dual 180-liter (47-gallon) domestic hot water tank
+
optional solar thermal system
SPE1 with 2 Roth collectors (2 x 2.52 sqm (27 sq ft))
including a 400-liter (106-gallon) water tank.
If the solar thermal system is installed, the 180-liter (47-gallon) heat pump tank would likely be removed.
I am generally aware that both systems are rather designed for the summer months and show weaknesses in winter, but nevertheless, the extra cost for the solar system (€4,800) seems reasonable to me for ideological reasons… purely from a financial standpoint, it will probably never really pay off.
For the winter months, I am considering connecting the planned wood stove with water heat exchanger to the central water storage tank. For this purpose, something like a Novelan/Alpha Innotec MFS 600-liter (158-gallon) multifunctional storage tank would probably be necessary.
What do you think, is this all nonsense or somewhat justifiable?
Or just take the heat pump with a small water tank plus a regular stove for the living room (which is already planned, as mentioned)?
I am currently planning the construction of a new KfW40 single-family house.
The expert’s calculation resulted in the following (summary):
Heated building volume = 532 cubic meters
Usable floor area = 170 square meters
Qp-new building = 29 kWh/(sqm per year)
The construction company’s offer includes the following technology
(where KfW was only calculated with the heat pump):
Novelan heat pump LAD 5 (air-to-water heat pump)
Compact Station Dual 180-liter (47-gallon) domestic hot water tank
+
optional solar thermal system
SPE1 with 2 Roth collectors (2 x 2.52 sqm (27 sq ft))
including a 400-liter (106-gallon) water tank.
If the solar thermal system is installed, the 180-liter (47-gallon) heat pump tank would likely be removed.
I am generally aware that both systems are rather designed for the summer months and show weaknesses in winter, but nevertheless, the extra cost for the solar system (€4,800) seems reasonable to me for ideological reasons… purely from a financial standpoint, it will probably never really pay off.
For the winter months, I am considering connecting the planned wood stove with water heat exchanger to the central water storage tank. For this purpose, something like a Novelan/Alpha Innotec MFS 600-liter (158-gallon) multifunctional storage tank would probably be necessary.
What do you think, is this all nonsense or somewhat justifiable?
Or just take the heat pump with a small water tank plus a regular stove for the living room (which is already planned, as mentioned)?
N
Newbie1233 Feb 2016 12:46So, for the heating system, you don’t use a storage tank at all; instead, the water circuit of the underfloor heating is used?
I won’t comment on the stove—you mentioned yourself that the main argument is coziness. If that factor is very important to you, then spending money on it without any guilt makes sense.
Regarding solar thermal systems—in combination with an air-to-water heat pump, I would personally consider photovoltaic panels instead. You can use the electricity produced yourself, and potentially also supply the power demand of your air-to-water heat pump. This way, not only is the ideological approach fulfilled, but it can also be economically reasonable (at least partly).
We have a Vaillant ground source heat pump with a 175-liter (46-gallon) tank for four people. Last weekend, for the first time in over a year, we noticed that it was not sufficient: after two children had bathed and my wife took a long shower, she wasn’t able to fill the bathtub completely with warm water.
As far as I know, the tank is usually emptied to a certain percentage before cold fresh water is fed in again and heated. This seemed to be the case with us last weekend as well.
Additionally, the water in the tank is heated to a specific temperature. When drawing water, cold water is mixed in to reach a comfortable temperature. So, from 175 liters (46 gallons) of hot water, you get XXX liters (XXX gallons) of water at a comfortable temperature.
If I wrote something incorrect, please feel free to correct me.
Regarding solar thermal systems—in combination with an air-to-water heat pump, I would personally consider photovoltaic panels instead. You can use the electricity produced yourself, and potentially also supply the power demand of your air-to-water heat pump. This way, not only is the ideological approach fulfilled, but it can also be economically reasonable (at least partly).
We have a Vaillant ground source heat pump with a 175-liter (46-gallon) tank for four people. Last weekend, for the first time in over a year, we noticed that it was not sufficient: after two children had bathed and my wife took a long shower, she wasn’t able to fill the bathtub completely with warm water.
As far as I know, the tank is usually emptied to a certain percentage before cold fresh water is fed in again and heated. This seemed to be the case with us last weekend as well.
Additionally, the water in the tank is heated to a specific temperature. When drawing water, cold water is mixed in to reach a comfortable temperature. So, from 175 liters (46 gallons) of hot water, you get XXX liters (XXX gallons) of water at a comfortable temperature.
If I wrote something incorrect, please feel free to correct me.
S
Sebastian793 Feb 2016 13:20That’s true, but since we like to take long showers and have a very large rain shower, I planned for 400 liters (105 gallons).
Sebastian79 schrieb:
a very large rainforest showerWe have the same – two rainforest showers. Did I already mention that I love our showers 😀
f-pNo schrieb:
us too - two rainforest showers - have I mentioned before how much I love our showers 😀Yes, you have 🙂 again and again - I like it 😀
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