To generate clean sine 230/400 V three phase you need about +/- 340 Vdc bus voltage. There are several methods to generate this DC voltage from single phase 230 V, such as:
Use a voltage doubler rectifier, since the peak-to-peak voltage is
2x325 V. Unfortunately this would need _huge_ capacitors and still the output voltage would be flat-topped.
Put an auto transformer in front of the voltage doubler. This would help somewhat but would be heavy.
Use a DC/DC boost converter between the single phase rectifier and the DC capacitors. If a PFC is required, it is usually implemented with a DC/DC boost converter. Adjust it lo generate at least +/- 340 V. As the DC/DC converter can be used for both PFC as well as boosting the DC bus voltage, so not much extra cost needed.
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N
NY
Do you find that forced (ducted) air central heating actually keeps the house warm? I suppose it must work, or 60% of American homes wouldn't use it!
My parents bought a brand new house in the early 1970s (so 1970s technology (*), admittedly!) which had gas-fired ducted-air central heating. And the house was never really warm, especially at the remote end of the ducts, where you got a feeble waft of tepid air. Even the ducts right next to the boiler/furnace gave out tepid air, even if there was more of it. And the house was very dusty because the constant draught kept dust circulating in the air. Our neighbours replaced their CH system with radiators when the boiler needed replacing twenty years later, rather than going for another ducted-air boiler. They said to us "at last the house is warm".
At least our ducted-air system was fairly quiet. When we were looking for a house a couple of years ago, we looked round one with a heat-pump/ducted-air system which emitted a constant moaning whining noise throughout the whole house - you couldn't escape from the infernal whining.
(*) The boiler was massive: about the depth and width of a typical fridge, but about 7 feet high - a floor-to-ceiling cabinet. The only room in the house that was really warm was the downstairs toilet which had the boiler in it, which suggests that a lot of the heat from the burning of the gas was wasted to the room rather than going into the ducted air.
C
Cindy Hamilton
Yes, I do. It keeps the house at a comfy 71 F (that's about 21.7 C). The filters in the return-air plenum clean the air. The furnace is about 20 years old and it's still performing beautifully. It is installed in the basement; not all the ducts there are insulated, yet enough warm air makes it throughout our single-story house to warm even the farthest rooms.
Last year we spent about $70 on heating in February. I expect it might be a bit more this year.
It also affords us an opportunity for central air-conditioning, for the hot and humid days of summer.
M
Max Demian
No, it's because the thermostat is faulty or badly calibrated. Every few days the compressor *might* turn off, usually for about three hours. I can live with it.
R
Rod Speed
Certainly does here. No one except poms use water based central heating here and very few poms here do either.
Yep.
Just a hopelessly done system.
We don't get that here.
Another stupid design. You can't hear anything with ours.
Yeah, f***ed by design.
C
Carlos E.R.
Not when there is ice in the evaporator surface. It is not a problem with the thermostat at all.
M
Mark Lloyd
[snip]
and in transmission lines.
V
Vir Campestris
Carlos, I hope you have a CO detector? It doesn't take a lot to go wrong with a portable stove to produce poison gas.
Andy
T
The Natural Philosopher
My late mother relates a story from presumably the 1920s, in which she and her sister and young brother were playing in a room with a paraffin heater. In the sort of trust in adults displayed by BBC audiences,, the ideas that she couldn't see in front of her for black smoke, and was coughing, didn't seem to create any alarm whatsoever until her father rushed in and opened all the windows and dragged the children out.
C
Commander Kinsey
The kids were so thick they didn't think smoke was bad?
C
Commander Kinsey
I have one in my head, it's called getting a headache. I don't waste money on safety s*it.
M
Max Demian
It's always behaved like that, including just after a full defrost.
M
Max Demian
It's always behaved like that, including just after a full defrost.
M
Max Demian
It doesn't have one that I know of. How would I know?
M
Max Demian
Domestic Hot Water. Heat pumps don't heat it to a very high temperature. Probably enough for a bath or shower, but some are afraid of legionella and what not. I don't know how much danger there is in domestic systems.
C
Carlos E.R.
Exactly. Bad design.
C
Carlos E.R.
Exactly. Bad design.
C
Carlos E.R.
There is some danger, if the water is warm but not hot enough to kill bacteria, but nice for bacteria growth. Domestic or not doesn't matter.
C
Carlos E.R.
I checked. These stoves do not produce it, and the room has a little forced ventilation anyway. Blue flame.
They come with a CO2 detector, though. If it triggers, the space is not sufficiently ventilated, so the tiny amount of CO they might produce does not build up.
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DOC: see page 5 (Spanish):
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No CO.
C
Carlos E.R.
That's for CO2, fumes, and lack of O2, not abundance of CO.
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