Geothermal energy: what power of PAC choose?

[yo16]

Good morning all. I have just read your various comments on PACs, and these perplex me. I indeed plan to install one at my place as an oil boiler replacement. I have a very large well insulated house (15 years) which is composed of a very large apartment upstairs that I occupy, and offices and a T2 on the ground floor, rented (all about 300m²) all heated at around 22 °. I currently consume between 3200 and 3500l of fuel oil per year (without hot water). My heating engineer offers me an air-water heat pump of around 16kw. I asked other installers who raise their arms to the sky and offer me a device of 30kw at least. What do you think?
My son (electronics engineer) is of the opinion of my heating engineer, who announces an economy with the heat pump, of around 60% compared to fuel oil because I have an EJP meter. I specify that I live in Charente where the T ° does not often drop below 5 °, and only a few days a year. Since I do not know much about this type of investment, could someone advise me on the type of device to install, and if it is really worth it? Thanks in advance.

[Remundo]

Hello Yo16

1L fuel is equivalent to approximately 10 kWh thermal

Based on your fuel consumption, you need at least 3300 x 10 = 33 kWh of heating per year, which gives you an average power of 000 / 33/000 = 24 kW.

In summer, very little consumption, on the other hand, in winter, you can have peaks at 15 kW and more, even in Charente.

As the heat pumps have an efficiency of 4, that is to say that they make about 4 times more heat than what you inject into electricity, a 4 kW compressor can do the trick, i.e. a heat pump of 16 kW.

BUT BE CAREFUL, although economical, a 16 kW installation could be light in winter. A small additional heating with wood (chimney) would make you the complement.

To realize, you would have to measure your average consumption winter

Let C be your consumption in L of fuel oil, you find the winter thermal power required in kW by:

C x 10/24 / (nb winter days counted).

Suggestion: Do you have neighbors who have put a cap? Ask them if they are happy with it and the thermal power installed.

There you go, hoping it will enlighten and warm you

[Christophe]

1) For precise power, only a precise THERMAL BALANCE to give it to you ... the 30kW are certainly oversized but it all depends on the type of heat pump ...

Otherwise I agree with Remundo's approach ... as a first approximation ...

2) By heating to 20 ° C you will save 500 to 1000L ...

3) Here we are not too much for heat pumps for different reasons... you will quickly understand why by doing a little research: https://www.econologie.com/forums/search.php

The first is economic: the profitability of a heat pump is much less interesting in real life than on paper and this does not take into account the increase in the price of electric energy ... more aligned with oil than wood. ..

4) So pkoi not do a lift with wood? Or better, switch to 100% pellets + solar supplement in summer ...
https://www.econologie.com/forums/couplage-b ... t4933.html

Here is a complete dossier on the subject: https://www.econologie.com/pourquoi-choi ... -3606.html

[Christophe]

Ah I forgot, here is a complete technical file on heat pumps and their performance:

Summary (not detailed):

1 Choice and dimensioning of heat pumps
2 heat pump air / water
3 heat pump brine / water
4 heat pump water / water
5 Installation of heat pumps
6 Production of hot water and ventilation with heat pumps
7 Controls and adjustments
8 Integration heat pump heating system
9 Planning Help
10 Accessories

Download here: https://www.econologie.com/la-technologi ... -3389.html

[loop]

Hello

Here is the address of the solar realizations pages

http://amet.pierre.free.fr/map.html

that of Tigger

http://amet.pierre.free.fr/tigrou/gireauudot.html

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[Christophe]

Uh thank you but I think there is a lot of stuff!

[RV45]

Hello,

Well, I find your project excellent, because with this solution you will decrease considerably decrease your fuel consumption in a very significant way as well as your regret of C02.

As you have the EJP you therefore have interest to be in relief of boiler.

Several advantages if your boiler is still in working order:

The power of the cap must in this case dimension 70% of the losses, therefore a smaller, less expensive cap and a lower EDF subscription.

the red days of rocking on your boiler and possibly when the temperatures are very low but this always corresponds to red days. This makes it possible to pay electricity at an attractive cost.

Now in terms of dimensioning the 16kw seems to me very well to dimension for your region and your surface. This is in no way under dimensioned for boiler backup.

I myself am installed in cap on tablecloth in relief of boiler with a tariff edf tempo. I also have sun

Look in my signature you have the link of my installation presentation.

[dirk pitt]

Small table corner calculation:
current fuel consumption = 33000kwh / year
heated volume = 750m3
Charente DJU = 2000
intermittency coefficient = 0.8 (classic value in housing)
overall efficiency of the heating system = 0.85 (with a large ladle)
from which we derive housing losses

Dep = consumption x output / (volume x 24h xix DJU)

in your case: loss = approx 0.97W / m3. ° C which is correct without more

The maximum power will depend on the minimum exterior temperature at which we still want to be able to obtain an interior comfort temperature.
I explain, if as you said, it is 0 ° C once a year and that these days you can get an extra by a chimney, it may not be wise to size the heating according of these 4/365 = 1% of cases
still arbitrarily take an outdoor temperature of 0 ° C for an indoor temperature of 20 ° C
it gives us a power of:
0.97 * 750 * 20 = 14,6KW
therefore 16kw seems suitable.
If I dare say, the problem is not there.
if your current heating means is a water radiator heating, the problem is that the efficiency of these radiators is higher the higher the water circulating there. on average, water between 40 ° C and 60 ° C is required in the radiators.
The heat pump, for its part, has an efficiency which is lower the higher the temperature difference between cold source (outside air) and hot source (water from radiators).
so when the outside air is at 0 ° C and the water from the radiators is at 50 ° C, the efficiency of the heat pump is rotten (sometimes less good than that of an oil heating)
The heat pump works well if you keep a low Delta T: eg with a low temperature floor and as a cold source of ground water at 10 ° C
for the rest, distrust

[tigrou_838]

like we are talking about me, and moreover with my creation on the pierre site. APPER

I do not know too much about the cap, although before doing all my work I had to look at this more closely, but the solar is still much more interesting than the cap, especially with the wood as an adjunct, crhistophe I think is d agree with me.

I am 8 km from Cattenom, the biggest producer in France, and I can confirm that in winter as in summer, it works very well.

me and the electricity we don't really agree.

Tigger.

[loop]

Hello

To find out if the heat pump solution is suitable, there is a fairly simple test to do, it is to lower the temperature of the hot water circulating in the central heating
For this you must either:
lower the temperature setting of the boiler calorstat

turn the 4-way valve (if it exists) to mix the return water and the water coming from the heating body and obtain a colder flow

In both cases, choose a cold day for the test and lower this water temperature until the temperature in the home stabilizes.
If this temperature of water circulating in the radiators is higher than 40 °, it is that a low temperature operation (PAC for example) will not be suitable, with existing radiators

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