Edmonton Shoptalk

[ExcaliburKid]

Originally Posted by 240glt

Shop talk!

Anyone out there have any experience buying, selling, spec'ing or operating ultrasonic humidifiers ?

I want to get rid of my spray washers but don't want to go with steam generators for energy efficiency and maintenance reasons, and any media type systems are big, expensive and will drive the static pressure in my plenums through the roof.

I have a guy coming in for show & tell next week, but just curious if anyone here has played with one

Does your building have live steam? If so, have you considered using a pressurised steam dispersion grid?

I do have experience (somewhat limited) with atomizing systems, I'd be happy to discuss if you're interested

[240glt]

I do have an LP steam plant that heats my entire east complex, I weighed the option of tying in a steam line to a dispersion grid but I am concerned about the scent the anti-scale and biocide treatments might introduce. I looked at a steam-to-steam exchanger but the costs are prohibitive.

If I can get rid of the spray washers I don't have to replace my existing coils with copper+copper coils (I have several to do this year) I can go copper+aluminium which saves a pile of money as well. I spent some time a few years ago investigating atomizers but no one was really able to give a good demonstration of a system suitable for 50,000 CFM. I actually stopped thinking about it until the other day when one of my regular contractors mentioned the ultrasonic humidifiers.

Yes If you have any further info I'd love to hear it

[Airboy]

I seem to recall some time ago using an ultra sonic system but nothing for a 50,000 cfm system. I will check with a few people in the know and get back to you. but 95% of the time we use LPS.

[240glt]

For anyone who was following along on that discussion about the mechanicals at KR, I found out the other day that it will indeed be a 100% O/A system with a heat wheel. Compartmentals on every floor

[kcantor]

Originally Posted by 240glt

For anyone who was following along on that discussion about the mechanicals at KR, I found out the other day that it will indeed be a 100% O/A system with a heat wheel. Compartmentals on every floor

would i be correct in assuming that this means a constant and not a variable air volume though the wheel? and does that then mean constant throughout the floor or is this just to temper fresh air for vav mixed downstream on the floor? also curious as to where you are filtering? sorry if these are neophyte questions that sound silly to you pros.

[240glt]

Originally Posted by kcantor

would i be correct in assuming that this means a constant and not a variable air volume though the wheel? and does that then mean constant throughout the floor or is this just to temper fresh air for vav mixed downstream on the floor? also curious as to where you are filtering? sorry if these are neophyte questions that sound silly to you pros.

You can run variable volume through a heat wheel, in fact they become more efficient the lower air velocity across the media, to a point. There will be a curve in which the unit can run efficiently. Generally the speed of the wheel is variable as well, and will modulate to deliver a constant supply air temperature. The heat wheel/ MUA package will temper the fresh air to the compartmentals (it will likely also have a preheat coil downstream of the wheel) on each floor which will have the mixing box which will also pull return air back from the space, and probably a cooling coil. As the exhaust has to be drawn back up to the heat wheel each compartmental will be connected to a common exhaust riser. The compartmentals will likely be VAV as well, so the speed/volume of the compartmentals will affect the speed of the heat wheel supply fan. We call this cascading control.

You'd definitely filter right at the intake of the heat wheel, and probably a fairly high micron filter media because you don't want to have to be cleaning the heat wheel media very often. From there each compartmental will likely have a pleat filter in it.

I really like this configuration from an operational standpoint. The equipment is smaller, the control is better, the drawback being that it takes up real estate on the occupied floors.

[kcantor]

th

Originally Posted by 240glt

You can run variable volume through a heat wheel, in fact they become more efficient the lower air velocity across the media, to a point. There will be a curve in which the unit can run efficiently. Generally the speed of the wheel is variable as well, and will modulate to deliver a constant supply air temperature. The heat wheel/ MUA package will temper the fresh air to the compartmentals (it will likely also have a preheat coil downstream of the wheel) on each floor which will have the mixing box which will also pull return air back from the space, and probably a cooling coil. As the exhaust has to be drawn back up to the heat wheel each compartmental will be connected to a common exhaust riser. The compartmentals will likely be VAV as well, so the speed/volume of the compartmentals will affect the speed of the heat wheel supply fan. We call this cascading control.

You'd definitely filter right at the intake of the heat wheel, and probably a fairly high micron filter media because you don't want to have to be cleaning the heat wheel media very often. From there each compartmental will likely have a pleat filter in it.

I really like this configuration from an operational standpoint. The equipment is smaller, the control is better, the drawback being that it takes up real estate on the occupied floors.

sometimes i think i know enough just to know how much i don't know...

so overall system design is close to a typical vav system (one with less typical additional supplemental in-line heating and cooling) except your heat recovery is on each floor where it is closer to its redistribution within the building than capturing it "single source" near the exhaust exit and having to move it back into the building's systems (or using it elsewhere?)? any idea how many discrete zones per floor they are planning to deliver?

[240glt]

Originally Posted by kcantor

th
sometimes i think i know enough just to know how much i don't know...

so overall system design is close to a typical vav system (one with less typical additional supplemental in-line heating and cooling) except your heat recovery is on each floor where it is closer to its redistribution within the building than capturing it "single source" near the exhaust exit and having to move it back into the building's systems (or using it elsewhere?)? any idea how many discrete zones per floor they are planning to deliver?

Heat recovery happens right at the fresh air intake and exhaust. You need to temper the outside air you bring into the building regardless, the heat wheel tempers the air rather than a heating coil. The compartmentals take care of re- circulating and conditioning air within the space, the only air that needs to pass through the heat wheel is to make up fresh air requirements, so you don't have the typical large built in place AHU's you see in older buildings.

No idea on what the terminal systems will be, VAV is a good guess but there are many ways they could go.. and bear in mind most of what I've written here is supposition, based on my experience with similar systems

[kcantor]

Originally Posted by 240glt

Heat recovery happens right at the fresh air intake and exhaust. You need to temper the outside air you bring into the building regardless, the heat wheel tempers the air rather than a heating coil. The compartmentals take care of re- circulating and conditioning air within the space, the only air that needs to pass through the heat wheel is to make up fresh air requirements, so you don't have the typical large built in place AHU's you see in older buildings.

No idea on what the terminal systems will be, VAV is a good guess but there are many ways they could go.. and bear in mind most of what I've written here is supposition, based on my experience with similar systems

thanks - you're making me even more dangerous with various bits and pieces of knowledge (for which my consultants and trades will hate you) but i appreciate it.

[Airboy]

240 is quite right, and we are doing more of the 100% O/A systems ever day.
I had a look at KR as it was going up, looks like Radiant panels and reheat at the VAV boxes. My concern with the heat wheel is if they have a preheat on the O/A duct. you can run these systems pretty efficiently from -20 and up, any colder and you need to bring the O/A up to -20.

Its also easier to control building pressurization with these types of systems.

We are getting away from using the Fan Coils like in your building Ken.

And here's some info to make you more dangerous.
http://www.airxchange.com/resource-c...ion-design.htm

[240glt]

The rad panels are the only aspect of the project that I'm really not a fan of. They're quite simple in operation but if the heating loop is not controlled properly they'll generate nothing but complaints as the OAT drops. A control algorithm that reduces the temperature and increases the flow is desirable for a system like that, IMO. So rather than resetting the loop off OAT I prefer to look at the demand and reset the loop temp from there.

I worked with a few tilt coils and the efficiency of the heat recovery was absolutely amazing.. All the way down to -30 with no preheat required. But I found the coil extremely finicky to get working properly as the OAT fluctuates, and had some problems with the defrost cycle when the OAT got really low.

Yeah fan coils do seem to be falling out of favour. They are a maintenance intense item and of course accessing them once a space is all furnished can be a real pain.

[Airboy]

Originally Posted by 240glt

The rad panels are the only aspect of the project that I'm really not a fan of.


Yeah fan coils do seem to be falling out of favour. They are a maintenance intense item and of course accessing them once a space is all furnished can be a real pain.

Fan coils in certain installation, eg, open ceiling with the cloud tiles is not recommended because of the noise levels, especially as the filters load up.

Rad pans do not heat the air the way convectors do so the ramp up of space temp is considerably slower. One reason you don't put them in seniors home.

Now I must be off to learn how to spot and avoid asbestos in older buildings.

[240glt]

Ah ACM: if it's crunchy it possibly is, if it's chewy it likely isn't

Been through all those courses... Have fun!

[Airboy]

I don't know why I am doing it, I just let the contractors punch holes in walls and find the stuff.

As it was we just did an over view, the owner understands we are only doing a survey of the mech system and are not doing anything invasive or destructive.

[240glt]

We did our summer switchover to mechanical cooling today, April 14th, the earliest ever in the history of the complex. It's a very busy day filling the condenser loop and re-coupling all the secondary chilled loops up to the primary chiller circuit and then balancing the pressures at the top of the towers.

We always ensure that overnight temperatures are not dropping below -5 to run the cooling towers otherwise the sump heater can't keep up, and mid-April is still a gamble but this spring has been so ridiculously warm we have no choice. Usually I can free cool till at least the end of April, if not into early May

Crazy weather this year

[ExcaliburKid]

Yup, we're starting up air cooled chillers installed over the winter at new installations already which is crazy to me.
Usually don't have a proper load until end of April early May at best

[Airboy]

Originally Posted by ExcaliburKid

Yup, we're starting up air cooled chillers installed over the winter at new installations already which is crazy to me.
Usually don't have a proper load until end of April early May at best

In the early days it used to be we had to suffer until May 24 and rely on OA temps to cool the buildings. I could see the increased temps in the Downtown core but the burbs are still quite cool at night.

That said my office is quite cool right now and I heard the chiller on earlier.

Went to a site last week to get base line flow readings from a chiller that was to be replaced. Checked with the operator that everything was working ok. Went to the pumps to strap on the flow devices. then noticed that the pipes were disconnected from the chiller and the fluid drained. Informed the operator that his OWS was inaccurate. God I love industrial projects.

[240glt]

Lol. But if it said it's running on the console it has to be running !

[240glt]

Re-posting this to the Shop Talk thread from the arena thread before the screaming starts

Originally Posted by Airboy

Liked working with both Priority and Arpis. And your right you cn only throw so much man power then it becomes a CF. I was one of the last trades on site and that last few months you think nothing will be ready but it gets done. As long as they can get the VIs done the rest can be done after hand over.

Also love working with Goldbar and Schedndel.

Yup it's amazing how things can come together at the 11th hour. I still have the rings on my ass from many a late night Sitting on an upside down bucket in a mechanical room with my laptop on my knees fixing programming glitches

Speaking of that, do you know who got the 15900 on this job ?

[240glt]

Wow.. May 3rd and I'm running my 2700 tons of available cooling at about 80% load. This is totally unprecedented. For reference, last year I was still free cooling at this time

Pulled the cover off the condensing unit at home last night, hosed it down and ran the a/c for an hour before bed. Crazy

Edit: I'm down to 65% demand, so that was just a bit of a blip. But still...