A technical question

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.

When you are so F___ing smart why would you be asking dumb as question???

Reply to
Grumpy
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I like variety, today I'll be finishing op the installation of 42" data and advertizing displays for a major retailer for their layaway department. I got the network cables installed yesterday and hooked into one of the store's network switches to verify connectivity. I have to go back today to install two new power circuits to the darn things because there are no spare bolt in breakers left in the lighting panels. ^_^

TDD

Reply to
The Daring Dufas

Well I will let others read your last sentence and they can work out just how smart you are.

Reply to
<ramrod

I suppose we get involved in various things, here I have coax and LAN wiring all over the home for the transmission of movies to computers connected to TV sets.

I have yet to set up the system so I can send Hi Definition movies across the LAN, I shall have to look into that sometime.

Also I have 10 phones around the house.

I have a small LED display over the mirror over the bar which you can have running message on to welcome people etc. You can program it with a computer, or use a remote.

Darn wires everywhere, but I am not keen on using wireless for transmissions.

Here we do not have cable TV, but satellite, and you lose the picture when heavy rains fall.

There is a system being put in around Australia of optic fibre to most houses, mind you I think it will be many years before it is competed

That will solve the satellite problem with rain, also give us high speed internet access. At the moment internet is via ADSL though the copper network

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National Broadband Network

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//The Australian Government announced on 7 April 2009 it would establish a new company to design, build and operate a new high-speed National Broadband Network (NBN). The NBN will become the single largest infrastructure investment made by an Australian Government, accompanied by historic reforms to Australia's telecommunications sector.\\

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THE federal government is a week away from seeing the first sod of soil turned in the construction of fibre-optic backbone links for its ambitious $43 billion national broadband network.

Mount Isa in northwest Queensland will be the first site in mainland Australia to have fibre-optic lines laid as part of the government's $250 million regional backbone blackspots program.

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Almost 500,000 premises will see NBN construction start in the next 12 months.

Reply to
<ramrod

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There are some communities that have fiber optic links available to homes but with out searching I'm not sure about it in my area. I have heard of some folks getting it but it's not advertised as being widely available around here. ^_^

TDD

Reply to
The Daring Dufas

Oh fer chris'akes ......

Reply to
.p.jm.

50 % of which is tax.
Reply to
.p.jm.

just a freakin troll

Reply to
Steve

The plan here is to have all the homes connected to optic fibre.

Only ones way out in the bush will not be connected as far as I know.

Mind you it is going to take years to complete.

Reply to
<ramrod

What you need is a simulator program. There have been a few on the net. I typed in one from an old book, written in Fortran. You put in all the specs like piston displacement and RPM, evaporator and condenser temps, refrigerant, and it tells you HP and heat transferred. You can then draw an efficiency chart while trying different values of one parameter at a time.

Jon

Reply to
Jon Elson

Well, obviously, the LOWEST head pressure requires the least HP from the motor. So, getting the lowest temperature in the condenser and the highest temperature in the evaporator that you can stand and still accomplish the job is the setup that gives lowest energy input.

In many cases, changing refrigerant may give better results.

If you are heating a space with a heat pump, trying to get 130 F air is going to be a lot less efficient that some other scheme that heats the room at a lower temperature. So, a hot-air heat pump might be less efficient than maybe a radiant floor heat system.

Jon

Reply to
Jon Elson

This is a hot-air heat pump system, or something else? Best efficiency seems to be to run the condenser fan so the outlet air temp is as low as you can stand, and still think it is "heat" rather than "cold wind". If you slow the fan down, the air picks up more heat, but the compressor head pressure goes up, too. Throttling the suction reduces effective compressor displacement, but in a lossy way, also making the HP input increase. So, the most efficient way to lower head pressure is to keep removing the heat from the condenser as fast as possible, and not throttle the suction or the evaporator with a TXV.

Jon

Reply to
Jon Elson

Generally different refrigerants work better for different temp ranges. Also, one condensing unit will not be as efficient for BOTH people-space cooling and food refrigeration. You want to make the refrigerant go through the smallest temperature change throughout the cycle for best efficiency.

Jon

Reply to
Jon Elson

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

Reply to
Jon Elson

Wrong.

You just contradicted yourself.

'lowest head pressure...' = correct.

'highest temp in the evap ....' requires the exact opposite of that.

Correct. As I previously told him , the LOWEST head pressure that meets the load will be the most efficient ( blissfully pretending that that one factor determines SYSTEM efficiency all by itself, which of course it does not ).

Reply to
.p.jm.

Correct. Assuming that point is sufficient to meet load.

Reply to
.p.jm.

It was a mental exercise that may have lead to an interesting experiment in the real world. You may know of the existence of single condenser AC systems that have several evaporator/air handlers in different rooms of a house. I've worked on systems in restaurants that used a single refrigerant for air conditioning, small refrigeration and walk-in coolers. The refrigerant was R-22 and with certain adjustments and considerations, worked very well. Some day, after winning the lottery or getting an inheritance from a deceased unknown relative, I suppose I'll get to try my ideas for a single point refrigeration and AC system. ^_^

TDD

TDD

Reply to
The Daring Dufas

The Coast Guard ships that I have been stationed on used R22 in multi box refrigeration systems... 1 freeze box and 1 refrigeration box..... both operated from the same system. Cleaning seawater side of shell and tube condensers sucked.

Reply to
Steve

I've worked on a lot of water cooled ice machines that used city water and the things worked very well but around here, the price of water and sewer has gone sky high so folks have gotten away from water cooled condensing units.

TDD

Reply to
The Daring Dufas

How so? In heat mode the evaporator coil is the outdoor coil.

With a heat pump the coils are called indoor and outdoor, not evaporator and condenser because the 2 can switch roles.

Reply to
Daniel who wants to know

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