General > General Technical Chat
What is the real story around heat pumps?
Zarhi:
--- Quote from: m k on February 23, 2024, 07:46:00 am ---
--- Quote from: Zarhi on February 22, 2024, 08:53:28 am ---That's is situation with air source heat pumps from this morning:
Outside temp 2°C, humidity about 60%, clear sky, no rain, no clouds, no fog.
Pictures taken 3-4 minutes after defrost cycle completion.
--- End quote ---
Looks can be misleading.
The structure is what it is because air is not dense enough that lesser surface area would be enough.
Actual operation happens between refrigerant and inner wall of the pipe.
So the machine doesn't know that there is frost, generally it only knows that compression is fine or not.
Condenser/evaporator can be insufficient when general operation changes from the normal sufficient operation.
It can still be fine with visually not so fine looks.
--- End quote ---
Evaporator was fully clogged, no air passes at all. And fan operates at very high speed.
In this situations heat pump works with COP slightly under 1. Heat dissipated in compressor are transferred to inside unit. Power needed for fan is lost.
Marco:
Defrost circuitry can be very stupid.
tszaboo:
--- Quote from: Someone on February 23, 2024, 01:48:40 am ---Always jumping to single solutions for energy are putting up strawmen, 100% solar, 100% wind, 100% CO2 capture, heating only from seasonal storage. They're all as dumb as each other. Most people can and do leverage the diversity of the gird to provide their energy needs, backed with things that are impractical on a domestic level like pumped hydro and nuclear power.
--- End quote ---
A private individual can only do so many projects at home. Solar is one of them, heatpump is another (which I'm not against, just pointing out how it's not practical for existing homes, after my government forces millions of homes to use). Combined heat and power is feasible, if the government keeps their dirty hands away from our individual freedom, and allows us to connect to the gas grid.
So yes, maybe it's possible to resolve these with solar or nuclear or burning peat underground or whatever. I have zero control over that. Solar is great, because it's free as in beers. Any time I need to import energy is just more leverage on my life that I want as much reduced as possible. All the other solutions are just asking for more taxes, fees utility bills. It leads to energy poverty. We want to resolve this global warming situation without causing yet more damage to the standards of living.
--- Quote from: Someone on February 23, 2024, 01:48:40 am ---
--- Quote from: tszaboo on February 22, 2024, 09:22:38 am ---And yes, I do need 5GJ for a winter to be bearable in my home, dropping temperatures lower than most people keep here would be a respiratory hazard.
--- End quote ---
You're not needing that, its a want. As has been said repeatedly and in this thread even if heating is a need for health, heating the whole house is still a want.
But it seems this thread is now just the (outlier) UK gas price discussion, and the rest of the world still cant talk openly about heat pumps.
--- End quote ---
I'm done with this part of the discussion. I have the right for this declared by the UN article 25.
"Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family"
I'm sick and tired of people flying in private jets to meeting in Davos, trying to tell us that we have to lower our standards of living, and convincing millions of useful idiots of this. You should stop being a useful idiot. There are ways we can resolve global warming without "depopulation" or "great reset".
So I'm going to be very clear about this: You have no right whatsoever to tell me, or anyone else, what I can or cannot have for my standard of living.
coppice:
--- Quote from: Zarhi on February 23, 2024, 08:26:26 am ---
--- Quote from: m k on February 23, 2024, 07:46:00 am ---
--- Quote from: Zarhi on February 22, 2024, 08:53:28 am ---That's is situation with air source heat pumps from this morning:
Outside temp 2°C, humidity about 60%, clear sky, no rain, no clouds, no fog.
Pictures taken 3-4 minutes after defrost cycle completion.
--- End quote ---
Looks can be misleading.
The structure is what it is because air is not dense enough that lesser surface area would be enough.
Actual operation happens between refrigerant and inner wall of the pipe.
So the machine doesn't know that there is frost, generally it only knows that compression is fine or not.
Condenser/evaporator can be insufficient when general operation changes from the normal sufficient operation.
It can still be fine with visually not so fine looks.
--- End quote ---
Evaporator was fully clogged, no air passes at all. And fan operates at very high speed.
In this situations heat pump works with COP slightly under 1. Heat dissipated in compressor are transferred to inside unit. Power needed for fan is lost.
--- End quote ---
Where is this located? A heat pump's exchanger needs to be in a place with very freely circulating air. Anything closing it in not only reduces efficiency, as the air recirculates, but condensation builds up much faster. I see lots of people putting the heat exchanger in some dark corner of the world, so it doesn't look obtrusive or to make the noise less obtrusive. Good aesthetics tends to give poor operation.
Zarhi:
--- Quote from: coppice on February 23, 2024, 12:41:06 pm ---Where is this located? A heat pump's exchanger needs to be in a place with very freely circulating air. Anything closing it in not only reduces efficiency, as the air recirculates, but condensation builds up much faster. I see lots of people putting the heat exchanger in some dark corner of the world, so it doesn't look obtrusive or to make the noise less obtrusive. Good aesthetics tends to give poor operation.
--- End quote ---
One unit is south of the house, second unit is east. Both are in the same condition on same time.
But this is no matter. In 2 °C, 60% relative humidity and atmospheric pressure about 1000 hPa dew point is about -4.9 °C. So evaporator will build ice quickly no matter of location, air circulation and so on.
This morning was 3 °C, 30% relative humidity and 1012 hPa. Both outside units was clean, no ice at all, and no signs of water underneath them. So last night they doesn't look to defrost at all.
PS: Defrosting is clearly seen on graphs.
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