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Air conditioners (portable)


I have a "portable" air conditioner. It is incredibly useful. It is an essential tool for dealing with the shit weather we get over here - contrary to popular belief, it's not always cold and raining in the UK. I think I would prefer it if it was. A maximum temperature of 20 degrees C would suit me just fine. And hot weather is fucking horrible - in cold or wet weather you can put extra clothes on, but hot weather you can do fuck all about. The whole day, and indeed the whole night with the possible exception of a slightly more clement period at the rather useless time of between 3am and 5am, is spent in sweaty discomfort cursing the fucking weather. Everything I touch is damp with sweat, my clothes stick to me, drips of sweat fall off my forehead into the circuitry I'm working on and destroy it with short circuits, I can't sleep and my bed gets quite gross with sweat. Hot weather even follows you indoors, so you can't shelter from it - unless you have an air conditioner.

Today it was fucking hot. I don't have a figure - if I look at a weather map the isotherms are too depressing as they always show that where I live is right bang in the middle of the hottest fucking bit. Cunt. So the air conditioner has been running, and I have been extremely glad that I have it. I think it has done more for my comfort and wellbeing than any other thing I've bought apart from my motorcycle leathers.

But despite this, it is crap.

Its principal design fault is one of utter stupidity. An air conditioner requires two separate supplies of air. One which it draws from the room, cools down, and blows back into the room; one which it draws from outside, heats up, and blows back outside. Check?

Not this thing. It draws both of its two separate supplies of air from within the room. The flow rates of either supply are roughly equal. One stream of air it cools down and blows back into the room, the other it heats up and blows outside. So this second stream of air is sucking air out of the room and pumping it outside, lowering the air pressure in the room. OK so far?

Now, no room in which one might be using one of these things is hermetically sealed. So the lowered air pressure in the room causes air to be sucked into the room through all the cracks and crevices. The air which is sucked in comes, of course, from outside. Come off the rails yet?

It's hot outside. We're trying to cool it down in here. What do we NOT want to do with the place we're trying to cool down? SUCK FUCKING HOT AIR IN! What kind of moron designed this thing?

The saving grace is that at least it draws the two streams of air through different inlets, so I have been able to box in the inlet for the air which is heated up and blown outside, and connect it via ducting to the outside world. It makes a tremendous difference to the thing's effectiveness, and it is utterly infuriatingly stupid that it was manufactured with such an idiotic design fault.

That is not its only fault, just the worst one. Here is another one. As one would expect, it has three motor-driven components: the compressor, which is remarkably quiet, and the two fans, which are annoyingly loud. Well, the fans shift quite a lot of air, and they need to, so there's not a lot to be done about that per se... similarly it'd be a bit daft to complain about the annoying draughts they create, as unfortunately the thing can't work without creating air movement...

No, the cause for complaint is the way the thermostat operates. Of course it is a good idea to have a thermostat which turns the machine on and off according to the temperature. But talk about a fucking half-arsed job... it doesn't turn the whole machine on and off. Just the compressor. The bloody fans keep running. So the annoying draught and most of the annoying noise are present continuously, not just when it gets too hot. The only way to operate the thing is to turn the thermostat down to its minimum temperature, leave it there, and turn the machine on and off manually.

Unfortunately even this method doesn't get the bastard gadget to work properly, because more fucking shit design is evident in the case of the temperature sensor the thing uses to determine the temperature of the air in the room. This, as I'm sure you will agree, should be mounted in such a way as to be thermally coupled to the room air and as far as possible not receive any thermal input from anything else.

Again, that's not the way this stupid bloody thing does it. The temperature sensor is clipped to the evaporator matrix and is therefore cooled to a temperature significantly below ambient. So the fucking thing thinks it's achieved the set temperature and the thermostat cuts out, when the real temperature is well above the set point and it bloody well needs to keep running.

Naturally, as soon as I discovered this particular piece of stupidity, I unclipped the sensor from the evaporator matrix and relocated it somewhere where it only sensed the temperature of the room air. Great, I thought, now the thing might work a bit better. And indeed it did - until my modification revealed the presence of further elements of fucking shit cheapskate incompetent design.

What happens now is that as the temperature of the room air drops towards the set point, but well before it reaches it, the rate of heat transfer from the air to the evaporator matrix falls to the point where it is unable to maintain the evaporator matrix temperature above the freezing point of water. Atmospheric moisture condensing on the matrix can now no longer drip off into the collector tray, but freezes on the matrix until the entire matrix is blocked solid with ice. With the airflow now stopped, the air conditioner ceases to function, and it must be switched off and a hot air blower directed on the matrix until the ice has melted. Which is exactly the sort of thing you really do not want to be doing when the ambient temperature is too fucking hot to start with.

The solution to this problem is simple - fit an airflow sensor which detects the drop in airflow as the matrix begins to freeze, and cuts the compressor well before it freezes totally solid, in which case the remaining airflow is sufficient to defrost it within a couple of minutes. Cutting the compressor only when the matrix actually begins to freeze, and not (as originally designed) just when the room temperature just starts to become bearable, enables significantly lower temperatures to be achieved; the airflow sensor requires no calibration and is entirely non-mechanical, being made of electronic components costing about 50 pence total to me and about one penny tops to a Chinese manufacturer buying millions of them... Not only did they bodge it, they used a shitty bodge instead of a decent one, to save one fucking penny.

It is clear that the stupid bastard who designed the thing was not competent to specify matrices and air blowers of sufficient size and capacity to transfer heat from the air to the matrix at a sufficient rate to prevent freezing at the lower end of the operating range (a range which is already deficient, as the minimum temperature of 18 deg C can most charitably be described as "only marginally acceptable"). Having discovered their mistake, instead of correcting it, they fudged around it by positioning the temperature sensor so as to cause the thermostat to cut out before their mistake showed its effects. It really baffles me how such fucking incompetent morons manage to get a job designing things in the first place, let alone hold onto said job.

Then there is the excessive complexity of the thermostat itself. It's a fancy electronic thing with loads of buttons and lights and shit and it has loads of operating modes and if you tried enough combinations of the buttons you could probably get it to suck your cock. The thing is, I don't need an electronic device to suck my cock. I don't need zillions of weird operating modes and a wildly inaccurate digital readout of the current temperature. All I need is a simple bimetallic strip thermostat, and a knob to adjust its operating temperature, with a "continuous running" position at one end of the scale. None of this would really matter if it wasn't for the thing's distressing tendency to go into some silly mode of its own accord, and necessitate some frenzied and bad-tempered pissing around with the crappy buttons while peering at some of the dimmest, hardest-to-see indicator LEDs I've ever come across, trying to restore the life-giving stream of cold air.

Recently a further piece of design stupidity made itself apparent. There is a large tray which collects water condensing on the evaporator matrix. The edges of this tray are only just barely higher than the level of the drain tube. So if the unit is not precisely level, but tilted forward by an imperceptible degree, the collected water, instead of draining down the tube, spills over the edge of the tray and begins to trickle down among the works...

The first thing it encounters is the cocksucking device. This, being a purely electronic unit, could be placed absolutely anywhere within the case. So it was placed with great precision exactly where water dribbling out of the overflowing tray would dribble onto it. And, of course, fuck it. A fault which might result in no worse result than a damp floor is transformed by utterly stupid design into a fault which fucks the machine completely. At least it gives me an excuse to rip the cocksucking device out entirely and replace it with some plain simple switches.

But the water's career of destruction is not yet over. After fucking up the cocksucking device it proceeds on its way downwards and the next thing it encounters is the motor run capacitor for the compressor. This is a cylindrical can with a pair of spade connectors on its upper face. The seal of the can forms a rim around the upper face, like the rim around the upper face of a beer can only quite a bit deeper. The water dribbles into this rim, accumulates to form a puddle, and rises until it shorts the terminals. Electrolysis, corrosion, and general electrical mayhem ensue. It's a bloody good job there are no faults in the earth wiring... Why the fuck didn't they mount the fucking capacitor the other way up so this couldn't happen? Not just stupid, fucking dangerously stupid. If there was an earth fault this machine could quite easily fucking kill someone. It's a model "AC-9000R" from Focus DIY. Do NOT buy one.

A further piece of design stupidity is associated with the heat exchanger matrices. Over time, dust in the air being drawn through the matrices is deposited on the fins, especially in the case of the evaporator matrix, where the condensing atmospheric water vapour provides dampness which enables the dust to stick together and accumulate in a thick mat. This mat of dust both insulates the matrix and blocks the flow of air through it, and has a serious effect on the unit's ability to cool.

It should be blindingly obvious that this is going to happen unless the air conditioner is being operated in a clean-room environment, and so any sensible designer would make it possible to clean the dust off the matrices. But not these fuckers. The bleeding morons have hidden the matrices behind heavy plastic grilles which are an integral part of the casing and cannot be removed, so there's no way to get at the matrices without using various cutting tools to hack the grilles out. It would be very easy to design the casing to incorporate removable grilles, but the shitheaded cheapskate wankers have not taken this obviously necessary step.

And my final gripe... it is deficient in both its reach and its grasp. The lowest setting of the thermostat is only 18 degrees C, which is a bit marginal, especially when I get in from the hot outside and want to cool off as rapidly as possible. But that 18 degree setting is effectively a continuous-running setting, because I'm lucky if its nominal 2.5kW of cooling manages to drag the temperature of this fucking 5m x 2m x 2m oven down below 22 deg C. Which frankly just isn't bloody good enough. And the word "lucky" is significant. Sometimes it can't get the temperature below 30 deg C, which is fucking appalling in such a small room. But anything more capacious not only requires holes cut in the wall and stuff, which is a bit impossible in a rented flat, but costs an absolute fucking fortune - Americans, you may think UK gas prices compare badly to yours, but that's nothing compared to the relative costs of A/C.

Which is another thing. Why the fuck is it so bloody hard to get hold of A/C in this country and at a decent price? It can hardly be argued that there is no need for it. There's every need for it. It gets fucking hot. Not just occasionally, every bloody summer. Newspapers carry stories about people at work walking out because it's too hot to work, and about local electrical shops running out of stock of fans. Yeah, bloody fans, right, what about aircons? Fans don't make it any cooler, they just stir the air up and create annoying draughts. What is required is an air conditioner, which does make it cooler and lowers the humidity as well. But it's a right arse trying to find it. Most electrical shops don't have anything at all, and it takes a lot of searching to find it. When you do find it it costs three times what you'd pay in the States for an aircon with three times the cooling capacity, and it's crap. The internet searches necessary to locate a supplier make the shittiness of the situation painfully obvious.




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