electric bill

Yorky said:
If you listen to AtB the ceiling height doesn't matter (same 2.00m or 4.00m).
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True enough. Hot air rises, while the cool air from the aircon settles under hot air (until it heats up, and then it rises again as it is replaced by more cool air from the AC.) That creates a cycle effect. If the air at ceiling height can eventually be cooled by that method, it will happen much sooner where the ceiling is 2m high than when the ceiling height is 4m but unless you are over 2m tall you really won't notice...
 
Our May PEA bill is 3650.59

Not too bad considering the heat of the last few weeks. We're being frugal with the aircon, and keeping windows and doors closed instead of leaving them open - the theory being the same as closing the fridge door instead of letting the cold escape into the room. My missus still believes that the inside of the house will be cooler though when windows are opened even if it is several degrees hotter outside... hmmm.

39.2c outside right now. 35.4c inside, and the windows are closed. My version works.
 
Merlin said:
True enough. Hot air rises, while the cool air from the aircon settles under hot air (until it heats up, and then it rises again as it is replaced by more cool air from the AC.) That creates a cycle effect. If the air at ceiling height can eventually be cooled by that method, it will happen much sooner where the ceiling is 2m high than when the ceiling height is 4m but unless you are over 2m tall you really won't notice...
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There was a time when I couldn't even spell "Engineer".

Now I are one.
 
Merlin said:
True enough. Hot air rises, while the cool air from the aircon settles under hot air (until it heats up, and then it rises again as it is replaced by more cool air from the AC.) That creates a cycle effect. If the air at ceiling height can eventually be cooled by that method, it will happen much sooner where the ceiling is 2m high than when the ceiling height is 4m but unless you are over 2m tall you really won't notice...
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Being only a pretend engineer, I still reckon that a 2.00 high ceiling with the aircon positioned at 1.70 metres from the floor will use less energy to cool a room than a 4.00 high ceiling with the aircon positioned at 2.80 metres from the floor.
 
Yorky said:
If you listen to AtB the ceiling height doesn't matter (same 2.00m or 4.00m).
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I doubt that as, the open volume of the space has to have an effect of the calorific conversion of temperature, coupled with the insulation installed.
I'd ask @Rice this question. BTW, hot air doesn't really rise by itself, it is pushed upwards by cooler denser air below it.
 
Merlin said:
Our May PEA bill is 3650.59

Not too bad considering the heat of the last few weeks. We're being frugal with the aircon, and keeping windows and doors closed instead of leaving them open - the theory being the same as closing the fridge door instead of letting the cold escape into the room. My missus still believes that the inside of the house will be cooler though when windows are opened even if it is several degrees hotter outside... hmmm.

39.2c outside right now. 35.4c inside, and the windows are closed. My version works.
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I could not live indoors at 35.4*C. Not so bad outdoors with the cooling effect of the wind, but indfoors, no way.
 
nomad97 said:
I could not live indoors at 35.4*C. Not so bad outdoors with the cooling effect of the wind, but indfoors, no way.
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I would not be able to manage 35+ indoors unless I had a few fans working.

ceiling fans.jpg
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The blades are around 300mm higher than the room aircon temperature sensor, i.e. the sensor is 2.40 metres from the floor (the ceiling is 3.00 metres high).
 
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Yorky said:
Being only a pretend engineer, I still reckon that a 2.00 high ceiling with the aircon positioned at 1.70 metres from the floor will use less energy to cool a room than a 4.00 high ceiling with the aircon positioned at 2.80 metres from the floor.
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Most ceilings are 2.50metre high. Doors are 2.00metere high and there is always space above the door. Most aircons are positioned around 2,00metres. What would be the position with a 4.00metre high ceiling with the aircon fixed at 2.00metres
 
Prakhonchai Nick said:
Most ceilings are 2.50metre high. Doors are 2.00metere high and there is always space above the door. Most aircons are positioned around 2,00metres. What would be the position with a 4.00metre high ceiling with the aircon fixed at 2.00metres
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My ceilings are 3.00 metres high, living room and bedrooms, 3.10 metres high, bathrooms and kitchen (because the floors are lower). If my ceilings were 2.50 metres high I would risk serious injury from the ceiling fans!
 
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Merlin said:
True enough. Hot air rises, while the cool air from the aircon settles under hot air (until it heats up, and then it rises again as it is replaced by more cool air from the AC.) That creates a cycle effect. If the air at ceiling height can eventually be cooled by that method, it will happen much sooner where the ceiling is 2m high than when the ceiling height is 4m but unless you are over 2m tall you really won't notice...
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Do you have your ceiling fans blowing the air above down, or reversed to suck the air upwards?
 
Cent said:
Do you have your ceiling fans blowing the air above down, or reversed to suck the air upwards?
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We don't have ceiling fans, but we do use ones that are freestanding to circulate air, including cold air from AC units which then spreads faster into parts of the living room where the AC's fan doesn't reach. We also have the vanes on the AC units pointing downwards (and not across the room) as that cools the floor tiles and is a further aid to the comfort level.

I firmly believe that the technique described here and in my previous post makes a positive contribution to keeping the PEA bills low. The evidence is there if you look at my bills posted here compared with some other folks.

As for tolerating 35C indoors - I don't as a rule, but neither do I run the AC if I'm not using the room.

I keep an eye on the humidity level too: anything below 55/60% makes high temps more tolerable, while more than 65/70% has me reaching for the AC remote control almost regardless of the temperature.
 
Cent said:
Do you have your ceiling fans blowing the air above down, or reversed to suck the air upwards?
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My ceiling fans blow the air above down. I was told by an artichoke that 300 mm was the minimum distance required between fan blades and ceiling, 450 mm would be better.
 
Merlin said:
I keep an eye on the humidity level too: anything below 55/60% makes high temps more tolerable, while more than 65/70% has me reaching for the AC remote control almost regardless of the temperature.
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Back in '82 on my first venture into the desert (Qatar) we experienced daytime temperatures of 50*C but the humidity was very low. To say it was tolerable would be pushing it though.

We were running large vacuum pumps at the time which needed cooling water. We had 12 cu. m. tanks full of seawater into which we immersed nitrogen vapourisers. Expensive but it worked - just!
 
Yorky said:
My ceiling fans blow the air above down. I was told by an artichoke that 300 mm was the minimum distance required between fan blades and ceiling, 450 mm would be better.
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Imagine pointing a hair drier set to 'hot' down from the ceiling. If the temperature below is cooler, that will have the effect of heating it up because the heat at ceiling height is at the higher temperature . Obviously, a ceiling fan doesn't have exactly the same effect, but it is a similar principle.

If the ceiling fan is very powerful, it may push the air below it across and downwards and even horizontally to a degree. Air at a lower level will be forced to go somewhere because of it, but it is more likely to equalise the temperature at all levels than to cool the air at head height or lower.

We benefit from a cooling sensation when fans operate because of its effect of evaporating moisture that is released through the pores in our skin - in much the same way, for example, as a Bedouin might carry water in a slightly porous goatskin or sheepskin bag: the water oozes very slowly through the bag, and evaporates from the surface keeping the rest of the bag's contents cooler than would otherwise be the case. For anyone remotely interested, it is called Evaporative Cooling which occurs because the fastest-moving (hotter) water molecules escape as vapor, leaving behind the slower-moving (cooler) molecules.
 
12785.01 baht is my latest bill...400baht more than last month's horror.
Then there's 3600 baht for the other house, Connor's batching in..but several pumps supplying the bore pump and reticulation + our house water's included on that.
 
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