A technical question

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more little dribs and drabs of incomplete information?? still trying to milk this thread??
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On 11/21/2011 5:55 AM, Steve wrote:

Well heck, it's kind of interesting to find out how it's done at the other end of the world. ^_^
TDD
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"The Daring Dufas" wrote in message

Nope it is a unique design for my home, which I put together.
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On 11/21/2011 4:05 PM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

Now that I can understand since I hoped to get a really cool two story house I found nearby where I live now. I could have gotten the house with one of those Affirmative Action loans that crippled the economy. I knew better than to get tangled up in that mess because I had no backup. All it would take was me winding up in the hospital which actually did happen a few years later. :-(
TDD
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"The Daring Dufas" wrote in message

Although I do not consider domestic air conditioning my field, I would think the majority of home air conditioning years ago here were window units, then non ducted splits systems took over.
In general a home is Australia tend to be single story individual houses locate on their own block of land.
In the larger city where land prices increased there, apartments replaced the individual houses mainly towards the centre of the city, in the larger cities this is increasing as the land price increase.
This has steadily become more prevalent over the last 40-50 years.
The vast majority of apartments are 3 story as if they go any higher elevators must be installed.
As you get closer to the centre of the large city, high rise apartment building are more the norm, than 3 story buildings. This of course is a generalization.
These individual homes tends to make our cities quite large compared to the number if inhabitants.
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On 11/22/2011 9:53 AM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

I have a bit of experience with Australian construction techniques because in the late 1980's I worked out in the Marshall Islands and our prefab housing units came from Australia and I had a hand in assembling them. It was interesting to say the least. ^_^
TDD
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"The Daring Dufas" wrote in message
I have a bit of experience with Australian construction techniques because in the late 1980's I worked out in the Marshall Islands and our prefab housing units came from Australia and I had a hand in assembling them. It was interesting to say the least. ^_^
Prefabs may be used a little in the country, but would be rare.
Mainly homes are built of double brick, brick veneer (Brick outer walls with plaster board inside), Cement brick, some of timber but the timber places seemed to be getting less and less common. There was a period when asbestos was used in some homes on the outer walls but of course that has now long gone, although there would still be many homes like that at around.
Some of of the older homes were constructed of stone. When I lived in Sydney my house was fairly old and made of sandstone blocks.
Multi story apartments are usually cement.
I have seen shots of homes being built in the US using some sort of what appears to be sheets of glued together timber stuff, this is not used here anywhere I have seen.
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On 11/22/2011 12:48 PM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

That's panelized construction, the walls and roof are made of huge sheets of plywood with 2x4 studs glued between. Often electrical wiring, insulation and windows are installed at the factory, too. I live in one of these. The only downside is when running wires for phone, network or extra outlets and lights it is hard to snake them through the walls or ceiling.
Jon
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"Jon Elson" wrote in message of Baal wrote:

As I have said I have never seen that being used in Oz, and I wonder what the life of it is?
My brick house is around 30 years old and quite sound, but the kitchen cupboards need replacing as they are made of chipboard and it is starting to disintegrate.
They tell me that the new chipboard is OK as it has a newer glue, but I will have to give it quite a bit of thought when I get it replaced if I should use solid timber. Mind you if the new chipboard last in excess of 30 years it would outlive me I guess.
Although the wiring was quite OK I have replaced it as I wanted 3 phase power on and quite a few upgrades in the house, wiring wise.
Being brick veneer home (Brick outside with timber frame walls clad in plaster board) it is fairly easy to run the wiring down from the ceiling in the gap between the brick and plaster board.
The water pipes outside the house were plastic and so I have replaced them with copper. The pipes inside were already copper. In newer houses it seems the both the hot and cold water pipes inside the homes are sometimes install in plastic pipe. Maybe I am old fashioned but I prefer copper.The idea of a plastic pipe bursting in the middle of the night does not make me happy.
In Sydney they replaced all the underground gas pipes with plastic. Quite a big job as the population is around 4.5 million and it is quite a spread out city.
It seems to work OK as far as I know, they did the job around 15 years ago. It seems they just poked the smaller plastic gas pipes through the old metal ones and run them at higher pressure, so they did not have to dig up half the streets.
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On Wed, 23 Nov 2011 01:53:05 +1000, < snipped-for-privacy@truthonly.com.Sword of Baal> wrote:>

    I understand the AC units have to be installed upside-down, to prevent the compressors from spinning backwords ;-)
    Or is that China ????
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P.JM wrote in message

Actually our compressor spin a bit slower than yours, as the power supply here is 50 cycles.
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On 11/21/2011 5:55 AM, Steve wrote:

I guess some folks are sooo lonely that they will do anything to attract our attention.

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On 11/21/2011 12:17 AM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

The fan control is set

OK, well if you can keep condensing pressure below 200 PSI, that should be a VERY efficient R22 system.

This electric reheat is a very inefficient way to do humidity control. A dedicated dehumidifier would be a much better setup. Of course, if they never go on, there's no worry, but if they are used much, it would probably pay for a dehumidifier in one season.

Having the system jumping back and forth between heat and cooling will not be efficient. This changeover ought to be a seasonal thing, but may need to be a day/night change, depending on daily temp swings. Better insulation and thermal mass is the best way to fight those swings. It is a total waste of energy to cool during the day and heat at night.
Jon
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"Jon Elson" wrote in message of Baal wrote:

That is why I designed it that way, but on a hot day it would not be below 200 PSI, more likely 240 PSI.
My 6 ton system also had head pressure control and an oversized condenser, on checking it on a 40 c (104 f) day the head pressure was around 240-250 PSI.
40 c is the highest I have seen it get to here, once in over 9 years.
----------------------

First of all seeing the plant only will run when there is a fair load, the cooling will look after the dehumidification in all but a small time in the year.
The internal load will help.
I did consider putting an heat exchanger in the condenser line and heating water and storing it in a 90 gallon tank and using a hot water coil for reheat, but I could not justify the cost, considering how little the elements would be on.
It is a balancing act after all, running costs verse install costs.
In England the say if you are going to live in a house for less than 5 years, put in a cheap heating system that is more expensive to run. If you are going to live there a long time put a more expensive system in with cheaper running costs.
--------------
I have 5 major rooms over 2 air conditioning systems. so I would need 5 dehumidifiers. As I have already stated the 6 ton system produces 7.2 litres per hour (Almost 2 US gallons) of water. IE 172 litres per 24 hours
Dehumidifiers depending on size etc will remove 10 to 20 litres per 24 hours
Somehow I cannot see using dehumidifiers would be practical , sure using reheat is somewhat of a loss, but as the heaters rarely come on it is fine. Here the rooms are not turned on 24 hours a day, but only turned on when required.
Running 5 dehumidifiers 24 hours a day would not be exactly cheap.

I did not say it would be going between heating a cooling but would over shoot the set temperature, which would cause a bigger swing in the conditioned space than wanted.

It is a personal choice and here with the swings of temperature it is required.
Possible early morning temperature of 11 c (52 f) during what you would call winter (Dry season here) and in the same day and afternoon temperature of 27 c (80 f) considering there is an internal load in some of the rooms requires IMHO the unit should be able to determine automatically if heating or cooling is required..
Today it was 10 AM in the morning and 24.5 c (76 f) outside and 91% RH (raining outside) and 30 c (86 f) in the computer room with no cooling running.
So at that point I turned on a small RAC to bring down the temperature. As the 2.5 ton system s not operational yet.

I think you are working on places that get quite cold and do not have big swings of temperature, not the tropics like where I live where we can get quite large swings of temperature.
The ceiling is well insulated but not the walls, it would be a big job to insulate them with something that does not burn, as I would never have anything that burns in the house as an insulation.
I have looked at it and it is not really financially practical. Yes it would be a different story if we had ice and snow here, we do not !!!!.
Sorry, I do not want a 5 ton block of cement in my bedroom for thermal inertia :-)
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wrote in message of Baal> wrote:>

I am fully aware of that still comes the question what is the best head pressure to get the most economical amount of heat from the system, that is all I am asking

That is what I said.
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On 11/06/2011 11:12 PM, snipped-for-privacy@truthonly.com.Sword of Baal wrote:

To boil it down to the absolute minimum, there is only one case where RAISING head pressure will increase efficiency, and that is where the head pressure is so low that the system is circulating primarily gas to the evaporator. Once condensing is occurring, then you want to hold the head pressure right there, at the absolute minimum.
Jon
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wrote:

    Correct. Assuming that point is sufficient to meet load.
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<DIV dir=ltr> <DIV style="FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 14pt"> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV>A technical question.</DIV> <DIV>&nbsp;</DIV> <DIV><FONT size=4>Using R22&nbsp; I want to know what is the idea range of head pressure to get the maximum heat out if the system with the least power input, IE the most efficient head pressure on heating.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>Please no guesses, I do not want to run the system at 400 PSI and chew up heaps of power. </FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>I have ways of controlling the suction pressure thus controlling the head pressure within some limits. The condenser (Outdoor coil) is somewhat oversized so that again allows me a range of suction pressures while the unit is running on heating. Both the heating and cooling modes have TX valves for refrigerant control and there is a receiver in the system.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>No worries about low temperature IE freezing the outdoor coil as it does not get all that cold here.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>As I said the main aim is to get a good heat result with a minimum of power usage.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>So what PSI should I aim at from a design point of view on heating and economy?</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>--------------------------</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>Before a first year apprentice starts to tell me what the answer is, I have been involved in air conditioning for many decades, so am knowable on it. My design experience is mainly on straight cooling systems.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4><STRONG><EM>Yes and perhaps some&nbsp;one had to come be hind you, to get unit&nbsp;operating I know because people like me done it more then once! Like John dear Dearborn Mi. they paid $50K EE out of Il. for 3-4 weeks of work for doing absolutly nothing that took me less then half hour to point the problem out and corrected!!</EM></STRONG></FONT></DIV> <DIV><STRONG><EM><FONT size=4></FONT></EM></STRONG><STRONG><EM><FONT size=4></FONT></EM></STRONG>&nbsp;</DIV> <DIV><FONT size=4>I designed a 175 ton plant (the biggest I have designed) and started up one system that had 9 ton of refrigerant in it. Plus I commissioned a few plants that had 3,300 volt motors driving the compressors.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>---------------------------------------</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>Not that I had anything to do with it but I saw one interesting reverse cycle plant which had multiple large fan coil units and had 6 x Carrier&nbsp; 5H120 compressors on it all coupled together. </FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>For those not familiar with the Carrier 5H120 compressors they have usually something like a&nbsp; 100-125 HP motor driving each of them and are an unloading 12 cylinder compressor. </FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>Nominal tonnage is 120 tons. The system beside having evaporators and a condenser had balancing coils to take up any imbalance in the system, as any of the fan coils could heat or cool simultaneously if required as there were both heating and cooling coils in each fan coil unit.</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4>=========================</FONT></DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV><FONT size=4></FONT>&nbsp;</DIV></DIV></DIV></BLOCKQUOTE></BODY></HTML>
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Grumpy raved

Seeing I owned my company and was in charge of the installations and commissioning they worked.
It is no surprise to see someone like you come in who cannot answer the question posed and then rave on, as obviously you have no knowledge of any value.

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<DIV dir=ltr> <DIV style="FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 14pt"> <DIV><FONT size=4></FONT>&nbsp;</DIV> <DIV> <DIV style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none">&nbsp;</DIV></DIV> <DIV> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT style="FONT-SIZE: 11pt">&gt;&gt; Before a first year apprentice starts to tell me what the answer is, I have been involved in air conditioning for many decades, so am knowable on it. My design experience is mainly </FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT style="FONT-SIZE: 11pt">&gt;&gt; on straight cooling systems.</FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal>&nbsp;</P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT style="LINE-HEIGHT: normal" size=3>Grumpy raved</FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT style="FONT-SIZE: 11pt">&gt; Yes and perhaps some one had to come be hind you, to get unit operating I know because people like me done it more then once! Like John dear Dearborn Mi. they paid $50K EE out &gt; of Il. for 3-4 weeks of work for doing absolutly nothing that took me less then half hour to point the problem out and corrected!!</FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal>&nbsp;</P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=4></FONT>&nbsp;</P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=4>Seeing I owned my company and was in charge of the installations and commissioning they worked.</FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=4></FONT>&nbsp;</P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=4>It is no surprise to see someone like you come in who cannot answer the question posed and then rave on, as obviously you have no knowledge of any value.</FONT></P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=4></FONT>&nbsp;</P> <P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><FONT size=3 face=Arial>When you are so F___ing smart why would you be asking dumb as question???</FONT></P></DIV></DIV></DIV></BLOCKQUOTE></BODY></HTML>
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