How do you cope with the heat? My thoughts on using a portable air conditioner after 3 years

This isn’t a particularly decent twin-pipe system – i.e. a monoblock – but rather a standard, cheap (albeit robust) single-pipe mobile unit; in any case, the whole discussion centres on such single-pipe units and possible conversions to twin-pipe systems. So, by design, there are no heating elements or defrosting functions.
You can always set the schedule to reverse the function every, say, 2 hours for about 10 minutes as a simulation of defrosting. But I’ll wait for winter, fit a second pipe, and the test will reveal the truth.

@kotbury, how does this ‘dewajs’ heating theory work? Because in my system, when cooling, one fan circulates air through the evaporator (which is cold), whilst the other draws air from the room, pushes it through the condenser (which is hot) and expels it through a pipe to the outside.
And how is it supposed to work in heating mode? Does the cold air go out through the pipe?

jarekgol wrote:

Is it cold outside – is the pipe leaking?

Nothing’s flowing because you can’t create a vacuum. Besides, where’s the air going to come from to transfer its energy to the evaporator???
I suspect these rubbish units only heat using heating elements.
I’ve written many times that the very idea of a single pipe is completely nonsensical, because to take something out, you first have to… put it in.
Exhaust alone cannot work! There must be supply air. Those who sealed around the pipe’s exit through a window or other opening without ensuring an adequate supply of air to cool the condenser have found this out the hard way. They simply ‘cooked’ the air conditioner. If it had safety features, it would have switched itself off; if not, it could have led to the compressor motor overheating or other overheating/overload issues, potentially even causing the refrigerant to be expelled from the system.

kotbury wrote:

But when it comes to heating – which is, after all, the main reason I bought it – there’s one snag. These portable units don’t have a defrost function at all (nor a built-in heater) and when drawing in outside air at, say, -10°C, the evaporator – which acts as a condenser when heating – will freeze over sooner or later

Can it be upgraded?

Quote:

because it’s impossible to create a vacuum. Besides, where would the air come from to release its energy in the evaporator???

From the flat. Since when has the house been as airtight as the Orla 1 lunar lander? If it were, the natural draught ventilation in older buildings wouldn’t work at all and the residents would suffocate from carbon dioxide. Windows have their own micro-ventilation; if that’s not enough, the draught in the ventilation system reverses itself and the vents, instead of extracting stale air, supply fresh air from above the roof. It’s just that this is a bit of a catch-22, because the outside air is cold and you need extra energy from the air conditioning to heat it up.
But as in life – it’s not black and white – it’s grey. A single-pipe system heats a bit, loses a bit, but overall it comes out slightly in the black. To the chap who claimed that a single-pipe air-conditioning system heats using the compressor and that a fan heater would suffice – my air-conditioning draws 1.07 kW in its highest setting, and I have no trouble heating 40 m² with it in 0.5 hours, raising the temperature from 13 to 19 degrees. I don’t think a fan heater running at its lowest setting (as it draws 1 kW then) would heat such an area by even 2 degrees. My little unit does NOT have a heater.

And I’ll say it again – I’ll be testing the conversion to a two-pipe system this winter, and then I’ll report on the results without any further speculation.

PS. What benefit might the shut-off damper mentioned above provide? And the smallest version costs more than my entire air-conditioning unit.

kotbury wrote:

To the colleague who stated that a single-pipe air-conditioning system heats using the compressor and that a fan heater would suffice - My air conditioning draws 1.07 kW in its highest setting, and I have no trouble heating 40 m² with it in 0.5 hours, raising the temperature from 13 to 19 degrees. I don’t think a fan heater running at its lowest setting (as it draws 1 kW then) would heat such an area by even 2 degrees. My little unit does NOT have a heater.

Oh, I see you’ve got a perpetual motion machine – I won’t say another word then.

kotbury wrote:

PS. What benefits might the above-mentioned shut-off damper offer?

This is just an example photo. You don’t need that much outside air to ventilate a small flat. You can draw some from the room and some from the duct. You can even automate this and set a mixed cycle, either on a timer or based on various factors.

kotbury wrote:

Quote:

From the flat.

So you’re heating the flat with his warmth. Just like Baron Munchausen, you’re pulling yourself out of the swamp by your own hair.
Ew.

Janusz_kk wrote:

Ooh, I see my mate’s got a perpetual motion machine,

kotbury wrote:

My little unit does NOT have a heating element.

Are you sure? I find that hard to believe. I suggest you open the casing and find and photograph the 4D valve or… the heater.

Janusz_kk wrote:

kotbury wrote:

To the colleague who stated that a single-pipe air-conditioning system heats using the compressor and that a fan heater would suffice - My air-conditioning draws 1.07 kW in its highest setting, and I have no trouble heating 40 m² with it in 0.5 hours, raising the temperature from 13 to 19 degrees. I don’t think a fan heater running on its lowest setting (as it draws 1 kW then) would heat such an area by even 2 degrees. My little unit does NOT have a heater.

Oh, I see you’ve got a perpetual motion machine – I won’t say another word then.

But why jump straight to a perpetual motion machine? All it takes is for a single-pipe air-conditioning system to expel air at a lower temperature than the outside air, and you’re extracting energy from the environment (the expelled air is cooler than the incoming air, the volume is the same, so the energy balance is positive).

exlibris71 wrote:

it draws energy from the ambient environment

What environment??? After all, a single-pipe system draws air into the heat exchanger serving the condenser in cooling mode and the evaporator in heating mode from… the environment, but that of the unit itself, not the building’s surroundings.
Is that so hard to understand? It’s better to take a moment to think and not write nonsense that reveals a lack of understanding of physical reality.

>>21942638
If you’re expelling air from the room through an air-conditioning duct, the same volume of air must be flowing into the room from outside to replace it (via ventilation, draughty windows, doors, etc.), so if the air being expelled is cooler than that coming in from outside, you have a positive energy balance and it gets warmer inside (even without taking into account the energy used to drive this air exchange).

exlibris71 wrote:

if the air being expelled is cooler than the air coming in from outside, you have a positive energy balance

If my aunt had a moustache, she’d be… an uncle.
Let’s say it’s -10 °C outside the building. Inside the building, in a ‘heated’ room, let’s say it’s 20 °C.
To achieve a non-zero heating power balance, the exhaust air from the ‘pipe’ must be less than –10 by, say, 5K. That is, –15 °C.
And now a question for the originator of the idea: Is there such a SINGLE-STAGE refrigeration system capable of reducing the temperature of the air flowing through the evaporator by … 35 K???