Vacuum Tube Heat

[Brad225]

Hopefully one of the engineering minds can give me some direction on air conditioning.

We are adding a new split AC system for the master bedroom and my listening room. With the volume of tubes in my pre and power amps it makes a substantial amount of heat.

Is there any logical way to correlate watts x tubes = heat to use for the purpose of room calculations for sizing the system. It will be zoned to be able to push most of the air to the listening room when I am in there and maybe that will be enough if we size it for the actual space. I'm never listening to music when we would need the bedroom to be at low temp for sleeping.

We have talked about a mini split system with one condensing unit and wall mounted fan units in each room. I would prefer to not see it mounted on the ceiling, but I could probably paint it. It would be the easiest though only needing to have Freon lines and one Romex cable providing power. No air return needed.

Currently the only time it is an issue with heat in the listening room is when it is cooler outside. Then turning the thermostat down enough for the music room makes the house very cold.

Any opinions would be appreciated.

 

[amey01]

For an estimate, just look at the watts consumed by the amps (not power output, but input consumption).

Add that to the heat load for the room.

If your system can't cope with the equipment demand, maybe it just needs re-balancing and more air directed to the listening room?

But if you're going to put in another system, I definitely woudn't go with a wall-wart - ugly, noisy and they create drafts. Go with nice big, oversized, low-velocity ducts. My system is dead-silent in the listening room, and you can barely detect air-flow.

 

[Spike]

Looks like you have your work cut out for you with regards to cooling your system...

From ARC Anniversary Preamp spec:
POWER REQUIREMENTS: 100-135VAC 60Hz (200-270VAC
50/60Hz) 220 watts. Standby: 0.8 watts

From ARC 610T spec:
POWER REQUIREMENTS: 105–125VAC 60Hz
(210–250VAC 50Hz) 1700 watts at rated output, 2300 watts
maximum, 800 watts at idle, 370 watts standby.

Basically, you'll need to cool down (1700 watts x 2) + 220 watts = 3620 watts!

Ah, the length we'll go through in this hobby just to accommodate for those glowing tubes!

Good luck with your system,
Spike

 

[amey01]

Looks like you have your work cut out for you with regards to cooling your system...

From ARC Anniversary Preamp spec:
POWER REQUIREMENTS: 100-135VAC 60Hz (200-270VAC
50/60Hz) 220 watts. Standby: 0.8 watts

From ARC 610T spec:
POWER REQUIREMENTS: 105–125VAC 60Hz
(210–250VAC 50Hz) 1700 watts at rated output, 2300 watts
maximum, 800 watts at idle, 370 watts standby.

Basically, you'll need to cool down (1700 watts x 2) + 220 watts = 3620 watts!

Ah, the length we'll go through in this hobby just to accommodate for those glowing tubes!

Good luck with your system,
Spike

Yes - considerable heat. But don't forget, amps don't run at their rated output all the time - it is only for millisecond transients. At 800w at idle - unless you listen particularly loud, allowing 1000w (heat output) for each amplifier is probably more realistic.

 

[Rehan Azim Hashmi]

INTRODUCTION:

First i do not have a engineering mind. Wish I had a engineering degree. Then I could understand most electronics better and perhaps talk to them like electronic genius. In Karachi the weather gets hot not warm during the summer season. Last year during May and June the weather was incredibly warm, average 40 degrees centigrade during these two months. For three years we had given up using air conditioners in our house because of a variety of reasons. Too expensive electricity, low voltage and power breakdowns. Because of our experience during last summer we plan to use air conditioning during summer.

BODY:

In your case, I would recommend using two mini, like you say, split air conditioners. 2 tons each or in other words having a cooling capacity of 24000 BTU/ hour each. I recently had, by hired help, moved a 2 ton ac from the lounge, where there were 2 such ac's, to my music room. My ac is a split ac having a external condensing fan unit and a internal unit. For 2 ton or 24000 BTU/h ac I have installed a 30 ampere circuit breaker. The ac is fed power through a 7000 watt voltage stabilizer.

CONCLUSION:

Given the volume of your music room I would recommend a 2 ton or cooling capacity of 24000 BTU/ hour split ac. Split ac also available in 12000 BTU/h and 18000 BTU/h for smaller rooms.
Please obtain the opinion of a professional ac sales person.

 

[Brad225]

Thanks for all the input.

With what I heard here and internet searches, this is what I have come up with. I will still have an AC company do the Manual J calculations for the space though.

2 Power Amps @ 1000 watts each average as I don't listen loud = 2000W
1 Pre Amp @ 100 watts average = 100W
16 MR16 halogen bulbs 20 watts average = 320W

This makes a total of 2420 Watts from heat. 1000 Watts is = to 3412 BTU's. So if we use 2500 Watts that will = 2.5kw x 3412 that is 8530 BTU's. A Ton of BTU's is 12,000 making my 8530 about 71% of a Ton of cooling. (If I have gone off the rails here please let me know.) That seems that I would need about 3/4 of a ton of cooling just to offset the heat created in the room plus the room itself.

I found several charts showing a guesstimate sq.ft of cooling for average insulated homes in different parts of the country. All of the articles said to do the calculation though.

Here in Florida it showed 450-550 sq.ft. per ton of AC. The total square footage we will have between the music room and bedroom area is 1050 sq.ft. The chart shows that is with average insulation and we will use better than average windows and insulation so, based on my not so scientific process 2 Tons of cooling should be fine. Maybe.

 

[Rehan Azim Hashmi]

Thanks for all the input.

With what I heard here and internet searches, this is what I have come up with. I will still have an AC company do the Manual J calculations for the space though.

2 Power Amps @ 1000 watts each average as I don't listen loud = 2000W
1 Pre Amp @ 100 watts average = 100W
16 MR16 halogen bulbs 20 watts average = 320W

This makes a total of 2420 Watts from heat. 1000 Watts is = to 3412 BTU's. So if we use 2500 Watts that will = 2.5kw x 3412 that is 8530 BTU's. A Ton of BTU's is 12,000 making my 8530 about 71% of a Ton of cooling. (If I have gone off the rails here please let me know.) That seems that I would need about 3/4 of a ton of cooling just to offset the heat created in the room plus the room itself.

I found several charts showing a guesstimate sq.ft of cooling for average insulated homes in different parts of the country. All of the articles said to do the calculation though.

Here in Florida it showed 450-550 sq.ft. per ton of AC. The total square footage we will have between the music room and bedroom area is 1050 sq.ft. The chart shows that is with average insulation and we will use better than average windows and insulation so, based on my not so scientific process 2 Tons of cooling should be fine. Maybe.

Impressive calculations. 2 ton split ac for the music room area and 1 ton split ac for the bedroom area.

 

[Brad225]

2 Ton should cover both rooms Rehan. Thats if my calcs are correct. With the humidity here in Florida oversized AC is an invitation for black mold as there is to much moisture left in the building.

 

[Rehan Azim Hashmi]

The external condensing unit is preferable if practical to install in area where it is not exposed to afternoon direct sun light. Reason is makes cooling more effective.

My ac external unit is placed on 2 thick L shaped metal frames, 4 to 5 feet above outdoor floor level. Low height placement makes servicing easier.

The air conditioner internal unit external cover I can reach with my hands, arms stretched, in order to open to clean the air filters inside. Low height placement on the wall, 6 to 7 feet in my case, makes this cleaning of air filters easier. Internal unit air filters need to be cleaned after every 1 to 3 months and is dependent upon amount of dust in the air.

Have fun listening to music!

 

[Rehan Azim Hashmi]

2 Ton should cover both rooms Rehan. Thats if my calcs are correct. With the humidity here in Florida oversized AC is an invitation for black mold as there is to much moisture left in the building.

3/4 ton or 71 % of ton for heat generated by electrical devices.

For environment heat during summer season for 550 square feet 1 ton is recommended.

Since you have more than 1000 square feet for both rooms, 2 tons to neutralize environment heat.


Conclusion:

Overkill but 1 ton required to neutralize heat generated by electrical devices.

2 ton required to neutralize heat from the outside environment or sun.

 

[amey01]

This makes a total of 2420 Watts from heat. 1000 Watts is = to 3412 BTU's. So if we use 2500 Watts that will = 2.5kw x 3412 that is 8530 BTU's. A Ton of BTU's is 12,000 making my 8530 about 71% of a Ton of cooling. (If I have gone off the rails here please let me know.) That seems that I would need about 3/4 of a ton of cooling just to offset the heat created in the room plus the room itself.

Don't you guys just measure A/C output in kW as we do here? Would make it a heck of a lot easier

I will still have an AC company do the Manual J calculations for the space though.

This ^^^^^ The best thing you can do......so many things matter - windows facing west, insulation, amount of glass, etc.

Don't forget to account for people too - work on about 200w per person. I know, it seems insignificant, but if there are 5 people in the room, there's an extra 1kW.

 

[Brad225]

Don't you guys just measure A/C output in kW as we do here? Would make it a heck of a lot easier



This ^^^^^ The best thing you can do......so many things matter - windows facing west, insulation, amount of glass, etc.

Don't forget to account for people too - work on about 200w per person. I know, it seems insignificant, but if there are 5 people in the room, there's an extra 1kW.

Cooling and heating is measured in tons here to the best of my knowledge. Cooling units referred to as 1 1/2 Tons to 50 Tons. The heat in the unit if it is electric it referred to in KW. If I have a 2 Ton unit it will probably have a 3 kw heat strip and the condensing unit compressor is actually a heat pump. I don't know if you use heat pumps there. When you call for heat the compressor basically has the system running in reverse and heats the Freon to send to the air handler and the electric heat strip makes up the difference if the thermostat calls for more heat to meet the need.


The Manual J calculations is what you are describing where the windows, compass direction, wall thickness, insulation value and room dimension are put into a program and it reflects the cooling and heating needs. These calculations are required on an energy calculation form for the permit to be issued so the work can be done.

There are only 4-5 times a year when there might be 5 people in the room but thanks for reminding me. If the unit is sized properly under hot conditions it should not cycle off very often. The Freon leaves the condensing unit at 40 degrees and the air out of the duct should be about 49 degrees. So if it is cycled on more than off it should work OK. I just need to have large enough registers and enough of them to avoid noise. I am thinking 3 inlets and one for return air.

 

[Brad225]

3/4 ton or 71 % of ton for heat generated by electrical devices.

For environment heat during summer season for 550 square feet 1 ton is recommended.

Since you have more than 1000 square feet for both rooms, 2 tons to neutralize environment heat.



Conclusion:

Overkill but 1 ton required to neutralize heat generated by electrical devices.

2 ton required to neutralize heat from the outside environment or sun.

In theory I agree with you.

The way I am looking at it is, 95% of the time the amps will not be on. So for that 5% with the zone control I can push the majority of the cold air if needed into the listing room. During those times it will not be needed in the bedroom.

The issue with 3 tons is it will be to much conditioning for the space for the 95% of the time. If oversized it will not have enough cycled on time to remove the moisture from the air. Mold is a big issue here in Florida.

In a ideal situation I would have totally separate system for both rooms but that would be another $4,000 + or -. For 5% usage I don't think it is worth the cost. Now if we are talking $4000 spent on something Audio equipment related that sounds totally reasonable. Though maybe not to my beloved at this time.

 

[Rehan Azim Hashmi]

A interesting website in Pakistan to check household appliances prices.

www.whatprice.com.pk

4000 usd for 2 ton AC unit too much. Should be priced approx. 800 USD.

100 PKR to 1 USD. Exchange rate.

 

[Brad225]

A interesting website in Pakistan to check household appliances prices.

whatprice.pk.com

4000 usd for 2 ton AC unit too much. Should be priced approx. 800 USD.

One of the business I own with my brother in law is a restaurant service company. He holds a commercial license for refrigeration and HVAC covering that part of it.

My cost wholesale for a 2 Ton 16 seer variable speed heat pump and variable speed air handler to match is about $2400. Then duct work, thermostat, drain lines, copper line set, drain pan, exterior pad for the condensing unit and installation. I think it will be more like $5000-$5500 not even $4000.

I wish you were right.

 

[amey01]

. I don't know if you use heat pumps there.

Yes, we have heat pumps here. We don't use them on heat cycle much though.... :0

There are only 4-5 times a year when there might be 5 people in the room but thanks for reminding me. If the unit is sized properly under hot conditions it should not cycle off very often. The Freon leaves the condensing unit at 40 degrees and the air out of the duct should be about 49 degrees. So if it is cycled on more than off it should work OK. I just need to have large enough registers and enough of them to avoid noise. I am thinking 3 inlets and one for return air.

Get one with capacity control (inverter, variable displacement compressor, or digital scroll) and you won't have to worry about cycling.

If you can't do that, then you can ask them to install a staged unit (basically two smaller compressors - one about 66% of required capacity, and one about 33% of required capacity) and then the system can operate at 100%, 66% and 33% depending on demand.

We have high humidity here in Queensland too - and this is the only way to design systems here - otherwise humidity control on cooler days is non-existent.

Oh, and no system will be running freon these days, surely? It'll be R410a or R32.

 

[Brad225]

Yes, we have heat pumps here. We don't use them on heat cycle much though.... :0



Get one with capacity control (inverter, variable displacement compressor, or digital scroll) and you won't have to worry about cycling.

If you can't do that, then you can ask them to install a staged unit (basically two smaller compressors - one about 66% of required capacity, and one about 33% of required capacity) and then the system can operate at 100%, 66% and 33% depending on demand.

We have high humidity here in Queensland too - and this is the only way to design systems here - otherwise humidity control on cooler days is non-existent.

Oh, and no system will be running freon these days, surely? It'll be R410a or R32.

The condensing unit and air handler will both be variable speed for the Scroll compressor. I agree with what you are saying.

You are correct it is R410. I used Freon as a generic name most people would relate to.

 

[Rehan Azim Hashmi]

Sorry I mixed up the web address.

The correct address is www.whatprice.com.pk

Brad225 the price you pay for AC in USA is exorbitant compared to what we pay in Pakistan.