anti-renewables heat pump? Disadvantages and advantages

[Bardal]

Today, heat pumps have evolved enormously, and I would no longer take the aquathermy option, simple aerothermal energy guaranteeing normal operation, without extra heat, up to temperatures of -15 ° C. Common COPs now exceed 5.

especially not: the cop strongly depends on the cold temperature ... with -15 ° it will never do 15 ... it will just do better than 1!

with your drilling it gives you a constant cold source so the cop does not decrease when it is cold so when there is the most need

the water / water heat pumps are generally more durable because they are mounted sheltered from the weather and the gas circuit does not come out of the heat pump ... the air heat pumps are more fragile with the compressor outside and the circuit gas in the house

alas the water / water caps are generally more expensive

I never said that the COP was 5 at -15 ° C; it is around 2,5 at this temperature (with a PC), which is not ridiculous ... but today, we are talking more about SCOP, i.e. a COP on a season-scenario (Strasbourg climate), and it is frequent that this SCOP greatly exceeds 4. In 1979, these figures were inconceivable, even for a water-water cap (mine was given for 3).

I leave you responsible for your statement on water-water heat pumps ... At the price level, I paid mine, in 2000, € 4000 for a 13 kW heat pump, roughly the price of an aerothermal heat pump of the same power.

Today, "inverter" technologies, new refrigeration fluids and rotary compressors have greatly increased performance and reliability.

[Bardal]

why so much hatred for heat pumps? it's still better than simple electric heating!

Yes we can always do better than (the) worst

In primary energy, heat pumps are not terrible ... moreover, the marketing campaigns of the time claimed that it was "free and clean" energy, these two arguments are completely false!

This is where these counter arguments against the PACs started ...

Even by reasoning in primary energy, a heat pump with a COP of 4 or 5 has a "primary" COP of 1,6 to 2 ... We subsidize "energy savings" much lower than that (condensing boilers by ex.).

As for advertising .... it should be seen on the side of all renewable ... It is clear that all the fashionable themes unleash sour and pirate from all sides ...

nb national accounts of renewable energies (http://www.statistiques.developpement-d ... -2015.html ) includes the contribution of PACs; in 2015 and 2016, it was equivalent to that of wind ...

[Christophe]

Except that 4 or 5 of COPA (Annualized COP) is still extremely rare (except maybe in datacenter or industrial equipment with two or three-stage cycles) ...

A particular heating CAP has rather a COPA of between 2 and 3 (when the installation is well done and dimensioned) ... therefore at the limit of the primary 2.58 kWh that must be spent to make 1 kWh electric.

Be careful in some cases it is even possible to drop below 1 COP (lack of gas for example, intense cold, frosted evaporator ...) ... so the bill is worse than with convectors ... Some pigeons are are fooled by unscrupulous salespeople ...

On the other hand, a big advantage of heat pumps is that they can be coupled with renewable electricity, but few people have the means to invest in both a heat pump and in photovoltaic solar panels which make it possible to power, say 80 % this CAP ... (€ 40 investment)

As you have been using it for years, do you have an idea of ​​your COP or COPA?

My experience with heat pumps is limited to a small reversible air conditioning and I actually measured 5 of COP but it was in summer in the best conditions, see method (empirical but fairly reliable I think) here:

energies-fossil-nuclear / measurement-cop-reel-conditioning-reversible-airton-inverter-t12642.html
https://www.econologie.com/essais-calcu ... le-airton/

[Christophe]

nb national accounts of renewable energies (http://www.statistiques.developpement-d ... -2015.html ) includes the contribution of PACs; in 2015 and 2016, it was equivalent to that of wind ...

I don't really understand what it means (I didn't click), what does that mean?

a) that the consumption of heat pumps = production of wind power
b) the savings brought by the PAC = wind production

In the 2 cases I do not see well how to measure the CAP part ... except with more or less rough statistics? Indeed the consumption of a heat pump and its savings depend a lot on temperatures ... therefore outside and instructions ...

So unless doing surveys on the evolution of electrical consumption in individuals who have replaced convector by PAC and this over several years (at least 3 years I would say given the variability of winters) I do not see a reliable method.

In addition, many air-air (and air-water) heat pumps, like mine are reversible, so their use as an air conditioner during hot weather in summer (more and more the case) will confuse the figures ...

Anyway ... it's not won!

[Ahmed]

I find talking about "hate" about PACs to be totally caricature, why not use the term critical distance?
I knew the glorious (?) Era of the first PACs and the ensuing collapse, except for the water-water or water-air PACs, because these machines worked without overloads, thanks to the thermal consistency of the sampling source.
Those of the second generation (air-water) that I have seen recently (and I am not talking about sabotaged installations) do not present particularly breathtaking performances. The only one (to my knowledge, which is far from exhaustive) which is satisfactory is that of a neighbor who uses it as a replacement for oil-fired boilers, therefore in mid-season, which is the most favorable; however not sure that it is also favorable in terms of investment ...

[Bardal]

The contribution of pacs is counted in the category "thermal renewable energy" like solar thermal; the difference between the thermal energy supplied and the energy consumed is counted; Obviously, this is variable depending on the weather conditions of the year, exactly as is done for thermal solar energy and for the consumption of biomass (wood is still the first renewable energy in France, ahead of hydroelectricity, biofuels , then pac and wind power equal). All this comes under European (Eurostat) and international (IEA) conventions, such as primary energy / final energy correctives, obviously with questionable approximations ... Still, these figures are used very officially to assess the progress made by the various countries, in particular vis-à-vis European objectives. You can find some methodological details at the end of the document (p 130 ....).

Concretely, this means that the energy provided by the heat pumps is roughly equal to that produced by wind power (around 8 MTep).

Incidentally, the total of renewable energies, calculated according to this method, places France slightly above Germany as a percentage of renewable energy in overall energy consumption; there is also no particular merit, it is linked to the significant weight of hydroelectricity (Germany is a flat country, with no great resources on this side) and wood energy (we have a lot of forests ) ...

[Bardal]

I find talking about "hate" about PACs to be totally caricature, why not use the term critical distance?
I knew the glorious (?) Era of the first PACs and the ensuing collapse, except for the water-water or water-air PACs, because these machines worked without overloads, thanks to the thermal consistency of the sampling source.
Those of the second generation (air-water) that I have seen recently (and I am not talking about sabotaged installations) do not present particularly breathtaking performances. The only one (to my knowledge, which is far from exhaustive) which is satisfactory is that of a neighbor who uses it as a replacement for oil-fired boilers, therefore in mid-season, which is the most favorable; however not sure that it is also favorable in terms of investment ...

I really think that this is hatred for certain stakeholders, and certain associations; and not of critical distance (which it is rational and beneficial).

I also knew the not very glorious period of the first "general public" caps (I make the distinction, because the caps are neither recent nor crestfallen; the cap heating the house of the ORTF in Paris still works after 60 years) , and I also remember the naive astonishment of their first installers, like chickens in front of a knife ... Nothing was done at that time, under the auspices of EDF in particular (PERCHE system), and that could only give this discomfiture; the installation network, the technology, the manufacturing, nothing was ripe enough to launch large-scale marketing.

But I think that you have not ensured enough technological watch in this field where things have progressed enormously, the industrial phase being practically mature; current performance is respectable, and reliability, at least for "big" brands, as good as for heating equipment in general. Personally, I have been heating my little house in Brittany for 6 years with an air-to-air cap to "general satisfaction", and the cap installed at my mother's, yet bought a bite of bread at Brico-truc, has always valiantly provided its service since 11 years old. Well, three examples don't make a statistic ...

Your "so mid-season" shows that you do not know modern caps: they maintain a constant power down to -15 ° C, and offer COPs over the year close to 5; only one condition: they do not adapt well to radiators ... Air-to-air can have identical performance ...

@Christophe The possible operation in clim 'in summer is not exactly heat production, and therefore has no reason to be counted here; on the other hand, their electrical consumption is well counted in the general consumption of electricity (like that of winter besides).
We can certainly contest the conventions used to count these RES, but we will have the same problem for wood energy, solar thermal, biomass, biogas ... etc

[Ahmed]

You write:

They maintain (modern heat pumps) a constant power down to -15 ° C, and offer COPs over the year close to 5.

Power, but with a yield that collapses * ... But, I quite agree on the rest: the material is much more reliable (if correctly sized and installed) and its performance superior ... On the latter , you are right to say that I am a poor expert: the last ones that I saw did not seem fantastic, such as the one which defrosted "to the bottom of the car" while it was not even freezing ... the difference, in the sense that whoever does not break down can hope to get away with honorably, otherwise the cost of the intervention pushes the point of financial balance far back ...

The argument, often used and which is laughable, of the free calories contained in the air can be used to define any energy, even conventional: coal, oil, gas, uranium are free ... at the start.

* With RC, the efficiency of heat pumps will mechanically improve ...

[sicetaitsimple]

generators with cogeneration is much easier ... there is no technical problem to build the equipment ... the only thing missing is that edf buys the electricity produced at a normal rate without any costs d prohibitive installation ... there is especially no need for subsidized purchase price as for photovoltaics ... a purchase price simply a little lower than the sale price, because any merchant needs a margin ...

authorities.
That's the theory, but it would be interesting if you could give us an idea of ​​the electricity purchase price that would be necessary using a small numerical example.

Ah, no answer .... Yet Chatelot16 came back that way, sorry for wanting to call you again following a "rather easy" statement.

Any table corner calculation shows that individual gas or fuel oil cogeneration would require an electricity purchase tariff "in full" a tariff of at least 150 and more certainly of 200 € / MWh to be "profitable ", ie around 4 to 5 times the current price of electricity (energy share).

I am ready to contribute by my invoice and its CSPE share to the development of wind and PV at less than € 100 / MWh, not to the development of fuel oil or gas at 200 .....

But I take different figures if they can be argued.

[Bardal]

Except that 4 or 5 of COPA (Annualized COP) is still extremely rare (except maybe in datacenter or industrial equipment with two or three-stage cycles) ...

A particular heating CAP has rather a COPA of between 2 and 3 (when the installation is well done and dimensioned) ... therefore at the limit of the primary 2.58 kWh that must be spent to make 1 kWh electric.

Be careful in some cases it is even possible to drop below 1 COP (lack of gas for example, intense cold, frosted evaporator ...) ... so the bill is worse than with convectors ... Some pigeons are are fooled by unscrupulous salespeople ...

On the other hand, a big advantage of heat pumps is that they can be coupled with renewable electricity, but few people have the means to invest in both a heat pump and in photovoltaic solar panels which make it possible to power, say 80 % this CAP ... (€ 40 investment)

As you have been using it for years, do you have an idea of ​​your COP or COPA?

My experience with heat pumps is limited to a small reversible air conditioning and I actually measured 5 of COP but it was in summer in the best conditions, see method (empirical but fairly reliable I think) here:

energies-fossil-nuclear / measurement-cop-reel-conditioning-reversible-airton-inverter-t12642.html
https://www.econologie.com/essais-calcu ... le-airton/

Oops ... I had not read this post ...

1- latest generation heat pumps (already 2 or 3 years old) have any SCOP (standardized COPA equivalent) between 4 and 5 ... This is no longer exceptional equipment, but heat pumps combining rotary compressor, recent fluid, technical inverter, and fluid reinjection process during the cycle. The pioneers of the technique were the Japanese (Mitsubishi, Hitachi, Panasonic), but all the brands got involved, so the advantages were significant. Admittedly, these are laboratory measures, therefore quite theoretical, but in current homes (rt2012), the heated floors operate at such a low temperature that it compensates for the classic difference between theoretical and practical ... The two or three-stage has rather lower COP (the limitation is linked to the Carnot yield, linked in this case to the Delta T).

2- falling below 1 is impossible, but if there is a lack of gas, it means that the cap is broken (but we do not fall below 1). As for unscrupulous salespeople, they are rampant everywhere, including in photovoltaics and wind power.

3- in practice, each French person is likely to have renewable electricity, it suffices to sign an adequate contract (even with EDF or Total today). The investment is zero in this maturity. That said, I do not agree with this distinction, which is irrelevant in my opinion; I prefer, by far, to speak of carbonaceous energy, or not, or not emitting GHG ... But that is another debate ...

4- Measuring a COP, a fortiori a COPA, is completely beyond the reach of an amateur, even very well equipped. On the other hand, CSTB is responsible for certifying, after measurements, most of the PACs on the market; the results can be viewed on the "certita" site. So I only evaluated, from these results, the COP of my cap (it's relatively easy for a water-water cap) and its accessories; it is already old and I arrive at 3,3-3,5. It pretty much fits with my electric bills. But it's still rough work ...

5-a COP of 5 in air conditioning seems to me highly improbable: for heating, the electric power is added to the thermal power, so it is recovered, while in air conditioning, the electric power must be deducted from the transferred power; So if the heating cop is 5, the air conditioning "cop" will be 3 ... In air conditioning, we do not use the concept of COP but that of EER (Energy Efficiency Rating) which has nothing to do with it with the COP.

ps For me, nuclear energy is not a fossil energy (see dictionary); it is a fatal natural energy: radioactive materials, natural, will continue to disintegrate whether we use it or not; anyway, uranium and thorium will continue to emit radiation and evolve towards stable elements ... as long as we use the energy they give off ...