Trane Intellipak question

[hvt]

Hello all, despite 21 years as an hvac technician I have yet to work on an intellipak unit, I have seen plenty of whatever they were called pre - intellipak, and Voyager units as well.
My question is about variabe speed drives in the intellipak 1 units,
I understand that they are installed in the outside air plenum, are they in a weather proof enclosure?

The units I have in mind are 105 ton models, they have two 40 horse supply fan motors and one 30 horse power exhaust fan, they have IGVs and discharge dampers to modulate air flow, I am looking into feasibility of installing VSDs

so far it looks like it will fwickin expensive!

[BKLYNBORN]

Pre intellipak units were just called RTU's the clear language display or the UCP-2 controller made it intelligent according to Trane. As far as your statement that it is a lot of money to install drives on these units what did you expect everything is expensive just look at the price of refrigerant. I would not put good money into something that old because the owner should be thinking about replaceing the units instead of updateing them. Because they come with the drives allready inside the units in the back section not outside in an inclosure or live with what they have and rebuild the IGV'S thier is nothing wrong with they operate it's just that everbody is drive crazy today.

[Phisher]

I agree with BKLYNBORN it's not worth the money for something that old. The drives that come installed in the new Intellipaks are mounted in the oustside air plenum. The drives aren't mounted in a weather proof encloser because they need air flow to dissipate the heat.

[jayguy]

they are NOT mounted in the outside air plenum.

they ARE mounted in the outside air AREA and are sealed from the outside air. there are ventilation slots that expose the vfd cabinet to the return air for heat dissipation.

i would agree to the idea of not installing vfd's. not because of the age of the unit, but becuase the only advantage of removing IGV's and installing drives is the extra diagnostic ability (a rare need in these units) and 'soft start' use. other than that, there is an extremely long payback in most cases (probably on the order of decades).

good luck.

[allstar08]

Depending on where you are and what your electric rates are drives can pay off much faster then you think. How the unit is set up for static pressure will also make a difference. With the addition of local utility rebates, I have been a part of projects that have a 3 year ROI.

[jayguy]

attached is a diagram from trane on the power inputs versus type of fan modulation.

IF...you have inlet guide vanes already installed, there isn't much savings by going to a drive.

IF...you have constant volume, then yes, you could go to a drive, however, you still have to convert the system over to a vav type system and controls.

[GT Jets]

No offense, but you guys are whacked...

I would recommend installing VFD's on the supply fans on an Intellipack 1 in a heartbeat. Especially if the customer has no intentions of replacing the units any time soon.

The shear extension of the unit life would make it worth while. VFD's are stupid cheap these days (just stay away from the OEM's) and depending on the application, can pay for themselves in a very short time.

BTW, I don't see any mention of how old these units are.

The Intellipak I's VFD's are located in the return air area just adjacent to the power exhaust fans, which BTW is another awesome upgrade, installing VFD's on the power exhaust motors depending on how much the unit is in economizer mode.

Cut out the inlet vanes and throw them away.....30+year old technology, the savings with a VFD can easily exceed 70% of the supply fan motor watts....do the math.

GT

[hvt]

thanks for all replies, I should have mentioned that these units are only 10years old, they are expected to last at least another 15 years.
The building has Trane vavs throughout.

GT jets, jayguy, can you guys clarify, are they in the outside air plenum and sealed in there own cabinet, or in the return air plenum.

The reasons for VFDs are as follows

Hydro rates around here are relatively high and not expected to get any cheaper.

This particular system sees alot of runtime at low load, the factory fan speed is too high for the low load times, but enough for full load.(previous techs have looked into pulley changes)

During low load times the fans tend to send a slight vibration through the building, very annoyng on the top two floors (Previous techs have checked fan wheel balancing)

Building pressure is sometimes a problem if everything is not perfectly set.

[jayguy]

...the savings with a VFD can easily exceed 70% of the supply fan motor watts....do the math.

GT

and a vfd can easily exceed 105% of the energy used by the motor...do THAT math.

don't get me wrong, i am for vfd's...they can make things real simple and easy.

but the IGV's may have a rod or bearing break, perhaps a damper motor goes bad...but that's it. try to explain to a customer the cost of replacing a vfd where A LOT can break.

as for many installations, changing out a CV system to a VAV can be very advantageous in both comfort and energy savings...but wholesale change out of IGV's (which are used in VAV systems) is ridiculous.

it may be a great option...this unit is almost sounding like it may be worth it. but in MOST (please read that word as meaning NOT ALWAYS) cases, it just isn't worth it.

attached is a top-view graphic of where the vfd option would be installed in 2 different size units...keep in mind that it is not to scale. most of the options that i have seen take up the whole outside air end of the unit.

[GT Jets]

and a vfd can easily exceed 105% of the energy used by the motor...do THAT math.

don't get me wrong, i am for vfd's...they can make things real simple and easy.

but the IGV's may have a rod or bearing break, perhaps a damper motor goes bad...but that's it. try to explain to a customer the cost of replacing a vfd where A LOT can break.

as for many installations, changing out a CV system to a VAV can be very advantageous in both comfort and energy savings...but wholesale change out of IGV's (which are used in VAV systems) is ridiculous.

it may be a great option...this unit is almost sounding like it may be worth it. but in MOST (please read that word as meaning NOT ALWAYS) cases, it just isn't worth it.

attached is a top-view graphic of where the vfd option would be installed in 2 different size units...keep in mind that it is not to scale. most of the options that i have seen take up the whole outside air end of the unit.

I am going to have to respectfully disagree with you. A supply fan motor on a VFD, even if running at 100% speed can save energy, the information you gave was accurate about 10 years ago, but with the advances in technology in the last several years by VFD manufacturers and increased switching frequencies (like in the 10K hz neighborhood) the efficiency is almost ridiculous.

This machine is more than a little likely a VAV unit being that is has IGV's and the amperage average will be very high, with a drive, this will be a ton lower at most if not all static pressure settings.

When I was at JCI, I was a certified Eaton start up tech. and there are numerous calculators available to figure the savings, you have to have the ability to show the customer the value in payback, not installation cost. A typical conversion from IGV to VFD is about 2 years, meaning the VFD will cost nothing in 24 months, put that together with having to replace the belts less often and reduced operating noise and the value really stands out.

GT

[jayguy]

this is getting fun!

...A supply fan motor on a VFD, even if running at 100% speed can save energy...

so a motor running at 100% bhp does NOT USE 100% bhp?!?! in other words, a 75 bhp, belt driven supply fan motor, DOES use 75 bhp with IGV's but uses LESS than 75 bhp on a drive? what would happen if we took that same motor, installed a drive on it AND THEN installed another drive on that drive...maybe it would only use 50 bhp then.

...the information you gave was accurate about 10 years ago, but with the advances in technology in the last several years by VFD manufacturers and increased switching frequencies (like in the 10K hz neighborhood) the efficiency is almost ridiculous...

true. the energy losses in a drive ARE smaller now...but they are NOT less than zero...the losses are still there and they vary by manufacturer and use.

...This machine is more than a little likely a VAV unit being that is has IGV's and the amperage average will be very high, with a drive, this will be a ton lower at most if not all static pressure settings...

what?

...When I was at JCI, I was a certified Eaton start up tech. and there are numerous calculators available to figure the savings, you have to have the ability to show the customer the value in payback, not installation cost...

payback is all about installation cost. but payback may not cover replacement cost. if the energy savings is enough, then sure, but the cost is huge compared a damper motor.

...When I was at JCI, I was a certified Eaton start up tech...

i originally had something written here, but i retracted it.

...A typical conversion from IGV to VFD is about 2 years, meaning the VFD will cost nothing in 24 months...

so a drive installed on my neighbors window air will have a payback in 2 years? how about my washing machine...2 years? what about my bathroom fart fan?

the point that i am trying to make is that, just saying 2 years is inaccurate. 6 months to 1 year? sometimes. 2 years? sometimes. 10 years? sometimes.

...put that together with having to replace the belts less often...

i will agree with you here whole heartedly!

...and reduced operating noise...

usually but not always. SOME drives do help with power factor which can reduce those charges if they apply. however, some don't. drives can screw up the power quality to the building....see attached document of a 50 hp motor that was installed on a TR1 drive. in that particular case, it was a CV building converted to a modified VAV...fast payback there!

i like drives...i really do. they are over-used by the engineering community however. i just hate the 'install a drive on everything!' mentality that our industry has.

[GT Jets]

this is getting fun!

X2, I can do this all day long and twice on Sunday....

so a motor running at 100% bhp does NOT USE 100% bhp?!?! in other words, a 75 bhp, belt driven supply fan motor, DOES use 75 bhp with IGV's but uses LESS than 75 bhp on a drive? what would happen if we took that same motor, installed a drive on it AND THEN installed another drive on that drive...maybe it would only use 50 bhp then.

You are forgetting two very important factors.

1. VFD's generate the output phases artificially, so the switching to the motor becomes almost a square wave and the voltage imbalances are non existent, across the line, the loses are quite profound. With a motor running at 60hz, there is an energy savings there period. I will attempt to prove this in the next couple of days with a customers air handler, (maybe Tuesday).

2. Inrush current on start stop can be reduced dramatically, every single time the fan starts...Instant savings, not sexy, but still has teeth.

true. the energy losses in a drive ARE smaller now...but they are NOT less than zero...the losses are still there and they vary by manufacturer and use.

See above

what?

Just like it says, a variable air volume unit will benefit from a VFD across a very large set of operating parameters, the OP stated this unit runs at the very bottom end of the curve for great lengths of time, making this an ideal candidate for a drive retrofit.

payback is all about installation cost. but payback may not cover replacement cost. if the energy savings is enough, then sure, but the cost is huge compared a damper motor.

Not sure what you mean by this, replacement cost is irrelevant, because most VFD manufacturers offer up to three year warranties..The damper motor never was mentioned unless I missed it....

i originally had something written here, but i retracted it.

OK

so a drive installed on my neighbors window air will have a payback in 2 years? how about my washing machine...2 years? what about my bathroom fart fan?

I stated IGV unit, never once saw a window shaker with inlet guide vanes.....

the point that i am trying to make is that, just saying 2 years is inaccurate. 6 months to 1 year? sometimes. 2 years? sometimes. 10 years? sometimes.

Agreed, but I did say typical and obviously can vary a great deal...Buying power alone has a lot to do with it.

i will agree with you here whole heartedly!

Thank you.

usually but not always. SOME drives do help with power factor which can reduce those charges if they apply. however, some don't. drives can screw up the power quality to the building....see attached document of a 50 hp motor that was installed on a TR1 drive. in that particular case, it was a CV building converted to a modified VAV...fast payback there!

i like drives...i really do. they are over-used by the engineering community however. i just hate the 'install a drive on everything!' mentality that our industry has.

How does this pertain to reducing a noisy squirrel cage or backward incline cavitation? I think you missed a comment from the OP on the noisey fan when totally unloaded....

I can show many case studies on several buildings I maintain and have added VFD's on a lot of different types of equipment, IMHO they are the best bang for the buck and will defend my opinion based on real world examples, not on what an engineer tells me....

I personally think that VFD's in some cases are "under utilized"....

GT

[lipsoffurry]

Wow, you guys must be slow. I can't find the time to even read all that static. I would not consider installing drives in an old "C" style. Take a look at the leaking condensor coil and the rusty condensate pan. Let it eat or pull it off before Clarksville changes the footprint.

[GT Jets]

Wow, you guys must be slow. I can't find the time to even read all that static. I would not consider installing drives in an old "C" style. Take a look at the leaking condensor coil and the rusty condensate pan. Let it eat or pull it off before Clarksville changes the footprint.

Sunday at 9:30PM and was bored out of my scull....The question was not whether or not to change them out at the tune of $100,000, it was to add VFD's in place of the IGV's at the tune less than $10,000 which will have a potential payback to the owner.

Sometimes the value is in extending the life of a perfectly good working machine and saving some energy while keeping some money in the owners pocket until the economy rebounds (I'm thinking 2-4 years)...

I don't understand why some tech's/contractors have to always swing for the fence, ball games are won with base hits....Sorry for the baseball metaphor...

Once the unit's life cycle is ultimately done, you could always sell off the VFD's for about 30% of what they originally cost...Just food for thought.

I have several customers whom I have been doing work for for over 13 years. I look out for them, they keep me busy with great opportunities to improve their facility...Simple math.


GT