About basement parking lot heating

[wufi2004]

Can i use hot water/fan heater in garage ? I have hotwater from rooftop. Mostly for garage heating, what heater is better?

But i didn;t find this device on net. Can u give me some idea?

 

[friartuck]

Why do you need to heat the garage?

In the UK, the basement/garages aren't heated (unless you live in a really cold climate)

The biggest problem I would have thought, would be to ventilate it (not heat it??)

Anyway, a LTHW (Low temperature hot water i.e. 80/70C) water heater would be ok.

Generally, basements are fairly constant in temp (assuming you are below ground), so you shouldn't need much heat anyway.

let us have some more details..

Friar Tuck of Sherwood

 

[wufi2004]

I need to heat it because it's in Canada, lowest temp. is -25C.

I have two levels of parking garage(1500m2 each).Level 1 is from 1m to - 2m, level 2 is from -2m to -5m.

When i use cold fresh air of -25C for ventilation, I should heat it. Is it right? So i need to heat it.

Look forward to your answer. Thanks!

 

[wufi2004]

I saw some suspended water-coil fan powered heating device. But I cannot find the picture of this kind of water heating device.

Online, i could only find electric heating system.

The ventilation rate for parking garage is large 3.9L/s.m2. so i get a lot of cold air, so i need heating.

Where to find the water heating system pictures for basement garages? I mean the suspended steel box(exchanger). Thanks!

 

[ChrisConley]

Hi wufi,

Try Engineered Air -

http://www.engineeredair.com/

They are Canadian and have a number of lines of hot water fan coils, and also have gas fired (direct and indirect) make-up air units which you might find is better to use in a parking garage - rather than introducing the air cold and then trying to heat it.

As far as 'suspended water-coil fan powered heating device' try searching for 'fan-coil units' - or just go to McQuay, Trane, Carrier, or many others. They all have hot water coil fan units.

 

[ChrisConley]

The other thing you may be looking for is a unit heater - searching for hot water unit heater might get you where you want to go. And try:

http://www.rittling.com/products/uh.html

EngAir also has hot water unit heaters.

 

[GeneratorGrrl]

Chiming in from the Canadian prairies where, yes, heating underground parking garages is normal practice - lots of frozen and burst pipes otherwise, not to mention frozen car engines and tenants ranting at your heels :B

Wufi, the most common heating practice I've seen out here has been the unit heater (usually Trane :B ) Being in gas country, natural gas is the normal fuel; not sure what area you're in, so I'm not sure what your normal fuel is, but unit heaters are available in oil- or gas-fired models. I second the suggestion of talking to Engineered Air; they are very good and know our climate variations inside and out.

In addition to unit heaters, I have also seen finned-coil heat exchangers used. These are less common out here because of problems with freeze-up. Here in Alberta, it is not uncommon to get cold snaps where temperature can drop to -30C or even -40C. Water in a finned-coil exchanger can freeze at these temperatures, as it loses its heat so quickly, so a glycol mixture is usually used in the lines, 50-50 being the norm. You will want to keep that in mind if you are still considering a water-filled finned-coil exchanger for your make-up air unit.

Hope this helps
-==- GeneratorGrrl

"Eat well, exercise regularly, die anyways."

 

[wufi2004]

Thank you, all of my friends, you all help me a lot! I learned lot from you. But new problem comes.

I want to post a photo of hot water-glycol coil/fan device. It's the thing like what GeneratorGrrl said and like ChrisConley's website. I'm here in Montreal. I saw a new parking garage is using water-glycol/fan coil. Do I need to design coil size or I directly buy it from some company?

Now i'd like to know how to heat water to a high temperature?
I have a boiler at rooftop level. How can i heat water and glycol mixture? Or can u tell me how to insert glycol into hot water? Glycol can enter boiler? I should mention there are some residential appartments upstairs. How they use hot water if glycol is in the boiler?

Thank you!

 

[ChrisConley]

Glycol can enter boilers - and often does. Here in the colder part of the Canadian prairies (-40 deg winter design, sometimes hits –45 deg C) we often specify a 50/50 blend of glycol and water - particularly if the heat transfer device is going to be exposed to the cold.

You could add glycol to the boiler loop. The devices that heat the apartments can also take glycol. Glycol affect heat transfer though, and the apartments may not have enough surface for a glycol mixture. Rather than change the whole system you could create a separate loop, with the boiler heating a brazed plate heat exchanger heating a glycol loop, and then the glycol loop serving the unit heater. The link below is an example of what I’m talking about.

http://www.armstrongpumps.com/Data/pdfbrochures/Links/01_04_001/112.09_Heat_Exchangers.pdf

As to designing the unit, if you know the heat loss then you should be able to select the unit from the manufacturer's catalogues, which list units by capacity.

 

[friartuck]

Being from Canada, I think you might want to try Dunham Bush (I'm fairly sure that they are a Canadian company but also have a manufacturing plant also in the UK)

They make LTHW Unit Heaters which would be ideal for you.

You need to heat the incoming fresh air. Glycol at 25% should do to protect from freezing but Glycol is very 'searching' and so valves should be packed using the right type of packing etc.

Sounds pretty cool at -25. Wouldn't it be cheaper to emigrate. I'm glad I don't have your energy bill.

Friar Tuck of Sherwood

 

[wufi2004]

Thank you!

Yes, glycol can enter the boiler, but the residents in the building can use the hot water mixed with glycol for shower? Or how to seperate the heating system into two: one is for basement heating ,another is for residential faucet use, like shower, washing?

Note: Residents don;t use water to heat the appartments; they use HVAC VAV system.

Thanks again!

 

[ChrisConley]

If your 'boiler' is only providing domestic hot water, then it is more correctly classified as a dometic hot water heater.

The HVAC VAV system that ther residents use to heat their appartments must have some source of energy. Whatever that source is: use it in the parking garage as well.

Natural gas, oil, hot water coils or electric coils are all available for providing tempered air in spaces

 

[quark]

Technical

50% glycol(propylene) can take upto -35⁰C and it should be 60% if you want to go below that. Specific heat of glycol solution is below 0.8 kCal/kg ⁰C and you have to pump in extra 25% fluid for a constant heat flowrate. Further, specific gravity of glycol solution is 1.032, so extra power for pumping will be around 3.2%. Thus your total pump power will be increasing by 29%. You have to check your existing pipe sizes for these increased flowrates. Viscosity is also a problem at this concentration and this increases pump power and reduces heat transfer rates.

You can't use glycol solution for shower. You can use separate heat exchangers for heating up water(as close to the shower as possible) as suggested in above posts but again there is an energy concern.

Personal

If you have to circulate heated medium as long as the ambient temperature is -45⁰(or at any temperature lower than the comfortable temperature), then why you should go for any antifreeze solution?

Direct fired air heaters can be economic in your case.

Heat pump can also be a good option.

Environmental

I am glad for being at the other end of the temperature scale. It is +45 for five months in a year and there were cases when it was +40 at 9.00PM. The other day it was +15 and I was shivering down my spine.

 

[GeneratorGrrl]

Wufi, ChrisConley is right, it sounds like you have a domestic hot water heater, which will be quite unsuitable for what you have in mind. If your apartments are heated with HVAC systems, then unit heaters would be the better choice to look at for your garage. Unit heaters are self-contained, so they will be much more cost-effective than installing a new glycol boiler, pumps, fans, piping and heat exchangers.


"Eat well, exercise regularly, die anyways."

 

[friartuck]

Shivering at 15 degrees. Thats our Summer (well its not quite that bad. We still go around in T shirts at 10 degrees.

I think I might faint though at 45 degrees. Where are you...Saudi??

Friar Tuck of Sherwood

 

[ChrisConley]

I've only experienced 45 degrees a couple times. Each time I would sweat like someone opened a tap.

Once while traveling through Greece, it hit 47C. I was sweating like crazy and complete strangers would come up to me with squirt bottles and fans trying to cool me off - I must've looked pretty hot. Children would point at me (exaggerating only slightly)


However, when 'spring' comes around here, and it hits -8C or warmer, I'm in shorts and sandals.

 

[GeneratorGrrl]

Here we go... Sorry for the double post but I finally found a pic of what I'm talking about. Wufi, check this out:

http://www.trane.com/commercial/equipment/pc572.asp

This is what I see most commonly in local underground parking garages, and it is also what we use to heat our maintenance shop at my current jobsite. This is a natural-gas fired model, but I'm pretty sure there are oil-fired models as well; your local Trane dealers will have more information and be able to help you out with options.



"Eat well, exercise regularly, die anyways."

 

[wufi2004]

Thank you! So warmed you are! Some facts are:

1.The parking garage(about 40 cars) will share the boiler with the above appartments.Boiler is on the rooftop.The boiler also provides hot water for HVAC of appartments.

2.The boiler provides hot water for HVAC and basement; meanwhile, how to get hot water for shower/washing use? I need one more small boiler for residential shower/washing?


3.I'm worried about the unit heater will be freezing at -12F in Canada if the unit heater is using hot water from the boiler.(I'd like water coil-fan heater).

Thank you!

 

[quark]

I am from India(south) and can easily tackle the high temperatures, as you guys can with lower temperatures. I still remember,during college days, walking around in the midnoon smoking cigarettes.

wufi,

It may not be proper to have a common boiler for wash and shower as the loads are diversified and you may have to run your boiler unnecessarily for hours.

Generatorgrrl's link seems to be about a direct fired air heater and this is better when compared to hotwater coil types.

Regards,

 

[walkes]

A couple of comments:

Quark:

I was using some B&G software that indicates that a 50/50 solution of propylene glycol has a specific gravity of .99 to 1.01 for the typical boiler heating application. (@180°F the SG is .99, @ 140°F the SG is 1.01)

WUFI:

You can use your HVAC boiler tied to an indirect water heater to provide domestic hot water to the suites. (Viessmann website has such tanks and if you used a condensing boiler the efficiency would increase at low load). So you can run the propylene glycol solution through the boiler.

As you cannot heat your parkade via a make-up air unit (code issues), you do require some unit heaters at doors and possibly around the perimeter depending on your heat loss analysis.

Another means of freeze protection is to ensure the loop has constant flow through the unit heater coils, run the fans based on thermostat demand.