a/c install in a church

Brad White_44

Displacement cooling.

Ed- I will give you a call tomorrow. My dad is in the hospital; mild heart attack but is fine.

Maybe meet later this week.

Brad

ed wallace

a/c install in a church

I was asked to give a qoute for installing a/c in a church built in 1845 wasc thinking of 2 separate systems down the sides of church using spiral duct how would the pros figure the load ? any one in the Boston area willing to come look at the job and advise me willing to pay for advice

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jwade55_3

Something else to think about,

is ductless split systems. I've been involved in several churches where we used these. Not nearly as obtrusive as ductwork, spiral or otherwise, and lots of flexibility.

J

Brad White_43

Historic church, Ed?

Just want to be sensitive to the history and aesthetics. What is your time frame? Where is the church?

Never been in one

ed wallace

a/c in church

can only install mini splits on 1 side of church out of sight of general public job is in cambridge in central square time line is this spring/summer hopefully

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Brad White_43

Not far from me

I picture the church near the head of Western Ave opposite Prospect. Let me know. Take a walk over get a cup of coffee and check it out late afternoon someday. Next week is possible but not on Friday.

ed wallace

church

its the oe next to the ymca would be great to meet you brad i have keys to the church can go in at any time let me know when you are around

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Brad White_43

Let's be in touch Monday Ed (NM)

ed wallace

brad

can you call me when you get a chance

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John@Reliable_10

Ed, might think about.............................

Hi-Velocity air conditioning equipment, the ones with only a 2 inch hole for ducts, you could also add a water heating coil for quicker heat up for services during the heating season and that would be a great benefit. Ed any "good" wholesale supply house that you deal with should be willing and able to help you size it properly, call me Monday if needed as we do all of the above. John@SouthShoreSupply

clammy

a/c

Ed in the past i have worked for companies that did alot of churches old and new .On a few of the old ones we used standard residental units and mounted them in the attic and used a two stage stat to stage them ,we had also used standard package units and remote sensors for the t stat and tied the fans together and the a/c compressor would be again staged .We also sized the duct for lower then normal velocity and oversized the registers to really cut down on any noise issues churches are always generally very quite .I didn,t do any of the heat gain on these jobs i had just installed them but we never had any issues with noise or it being to hot in the church .I think the key to church jobs is sizing your ducts at a litle lower static and running it at residental velocity of about 700 to 800 ft per second with the proper sized registers the system will be very quite .peace and good luck ed always enjoy your posts clammy

Brad White_43

Feet per minute

I know that is what you meant, Clammy-

Even God can wait for her air conditioning or heat...



700 to 800 FPS is about Mach 1 and as fast as a .45 ACP projectile.

Boilerpro_3

My Opine....

Well not doing A/C myself, I recommend ductless splits for many reasons. First they disturb little of the existing structure, so worries about damage to historic buildings are kept to a minimum. Second they allow staging and better dehumidification because at light loads only one or two units need to run. This is especially important to this kind of space because the load varies widely depending on occupancy. Most of the time, loads are light because no one is there and, if it is a masonry structure, the mass evens out the daily peaks (thermal flywheel). Running large equipment at low loads will result in cold and clammy. Third, and this can be a biggie, staging should allow huge reductions in electrical costs. Most electricity suppliers have peak demand charges for high usage during peak business hours. Staged equipment can cut these costs dramatically. Forth, they allow zoning within the space, so areas of high occupancy (choir, pastors) can receive more cooling and the typically nearly empty front rows less cooling. This also should allow cooling of only certain portions of the space for things like musical and skit/play rehearsals.
Also, generally you want to mount the units low, so you only cool where people are at. If you have a balcony, or cooling the organ chambers is an issue, things get a little more tricky. Also, if this is a high mass structure, the addition of some controls could be very beneficial. I would recommend a timer setup be installed to lock out the A/C during the peak demand times and let the thermal mass coast through the day. A little precooling during night hours should allow this without temperatures varying wildly. Also, enthalpy sensors controlling a large exhaust fan can be helpful too. The exhaust fan would usually run during the wee hours of the morning to cool down the structure and shut down during the heat of the day. I have found that this can deep the interior temperature 10 to 15 degrees below the daily highs. This will again take advantage of the mass of the structure.
Careful load calculations need to be completed. Almost no one seems to take into account two big factors, the typically short time a sanctuary is occupied and the ability for the mass of the structure to absorb heat. I was taught to use the Cooling Load Temperature Difference method of cooling calcs, and these take into account occupancy period and mass. My previous church installed A/C when I was a member, and the recommended sizes were from 10 to 15 tons for a 300 seat sanctuary with 20 inch stone walls and suspended reinforced concrete floor and 21 foot ceiling. They have a single 1 hour service on Sundays. When I calculated the load taking into account mass and length of occupancy, I ended up with 6 tons. They installed 3- 2 ton ductless units and they work great. You can feel them pull down the humidity during the service as the temp rises a couple of degrees. Usually the space is more comfortable at the end of the service than the beginning because it is so dry.
The throw on most of these units is like 25 feet or more, if I remember correctly, so installing them on one side is Okay in most cases.
As to noise, I have yet to be in a church with Ducted A/C that was as quiet as the Ductless units, if you stick with quiet units like Sanyo and Carrier.
One last problem with ducted systems is the duct work is often run in a very hot attic, and you can guess how much cooling capacity you loose....probably 20% or more. In addition, all those holes in the ceiling are going to greatly increase air leakage and combined with the poor insulation of typical duct work and air handlers, the heating bill is going to jump to. I addition, with ducted systems you have to run another large blower, which generates additional heat the system needs to cool...just more waste. I sure wish the efficiency rating on cooling equipment took this blower power into account... I bet the efficiency of ducted cooling uints would drop like a rock.

Boilerpro.....I do lots of church work.

clammy

Thanks brad

Thanks Btad you know how it goes staring at a ductulator your head starts a spinning then you think your a fan on another note i would not think a unico would be the greatest fit i have run into a bunch of mis applied unico install one being a coffee shop (big name) and another being small server room niether one works to great every system has it's application and i feel uniceo place is better served in homes with tighter envouples or older k homes with historical preservation in mind but they don,t fare so well in commerical applications.Any buddy remenber duhman bush first hi vee systems i do and boy where they noisey in commerical office application may be that's why they let that ship sail 25 years ago .Peace and good luck clammy

JackFre

Mini splits

I represent Fujitsu in New England. We have two models of floor mounted evaps for this season in the 15-16 SEER range. The advantage is that evaporators sit below the sight line of the pews. They also have an extende line set of about 150+' (not sure on that, I don't have the spec sheet with me). I'd be happy to visit the job with you if you'd like.

don_163

its

not so much the envelope load nor the people load that get
your btu so high...its always the fresh air issue that require by code that doubles the load on cooling and heating equipment.

Mike E_2

We put AC in our church 3 years ago. When we were researching what type of system to put in, the code stated that if we went with a ducted system, we needed make-up air. This required a total of 13 tons (two 4 tons for the occupany load, and one 5 ton for the make up air load).

If we went with mini-splits, the requirement for make up air didn't apply, so we were able to put in a total of 8 tons (four 2 ton). Since the church is only used for 1 morning and 1 evening a week, there isn't a big need for make-up air.

Also, it would have been rather difficult to run ductwork without destroying the asthetics.

We went with the mini-splits and they have worked great. They are almost silent, and the 2 in the front don't look out of place at all. The only thing that I don't like about them is the remote control. I wish that you could have a programable wired thermostat connected to them. Someone always has to remember to stop by Saturday nights to turn the units on.

Michael

ed wallace

A/C in old church

if i go with ducted system i would put 2 units in both in rooms on either side of alter the ductwork would run down the sides of the church duct work would be exposed so ductless mini split systems might be better choice

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JackFre

Fujitsu allows this on all the new units

with optional wired remotes. Some models can control up to 16 units with one stat.

Mike E_2

Pics of a mini-split install

Mike E_2

Pics of a mini-split install

Mike E_2

Pics of a mini-split install

Here are some pictures of the mini-splits installed in my church.

I don't like the placement of the painting on the right, but it is only temporary for Lent. Then it will go back to its normal spot.