Energy Requirements For Known Volume Of Building

It must be probably warm down there? I know up North, such programs are offered by almost all suppliers of central heating to calculate the heat losses. Once you know the power to install, you can easily re- mount it for airco. I remember even size and type of window(s), insulation, type of roof, and many more items to play with to fill out than you summarize. I am a cold man. Do not need any airco, but your airco bill is my heating bill.

Hi Sir, I came to the Bahamas years ago, introduced the ICF (ICE) block and have built a 64.000 sqFt, a 16,000 sqFt and a 11,000 sqFt building with it. The walls are 12 inches finished and the styrofoam in and out adds up for 52% of the volume. My GE refrigerator does a lot worse. All slabs are 8 inches (or thicker) concrete between the levels. If you combine that with triple glazing in sealed PVC frames (trocal profile) and a good shade management from the outside, AC units as sold are obsolete. The typical ton/cubic feet is 1/3 of a typical subtropic building. The problem is that the smaller units are not designed for that volume of air. The only thing that the AC must do is get rid of some moisture. Temperatures are not the main issue. With this style house the AC is not even on for 2 months/year. 10 feet ceilings and air knife exhausts take out the heat just under the ceiling with 2 X30 watts Papst fans in a duct. There are 8 in the 11,000 sqFt building. When not in use they charge the batteries of a emergency light system with LED's in each room. (for power outages - we have many). To deal with the AC, I had to oversize the unit to have enough air changes. The 4 tons AC runs 7% of the time when on. (outside 40 *C plus and 85% RH plus, all the time). I thought of installing a heat pump and use the heat for the pool, but that water is already too warm.

I have ordered a AC unit on 24 volts DC and want to run it with solar. The 400 watts security systems are already run that way.

Thanks for making my mouth water. What a building!

Its all more basic down here. Small improvements already make a difference and in this case it is a light corrugated steel structure. If, for exampled, I would put the whole structure under shade, what difference would that make to my energy consumption.

I could measure the difference in temperature in a small model but that would not give me the amount of power I would save after I introduced the insulation on a large scale. The difference being what amortizes the insulation method.

What if I would attach 5" Styrofoam to every surface and how long will it take to amortize. The best case scenario would be if I could play around with these inputs on some calculator and work out the best solution. Somewhere between full shade and.........whatever.

Maybe I was a bit too optimistic about finding such a tool. Its early yet.

If there is an image of your house that you would like to share give us a look, sounds great.

Do you know how to recognize a level headed Australian? He drools out of both ends of his mouth equally and at the same time.

Thanks, Ky.

Never been more level headed Mate.

This image is more along the lines of what I am thinking of. More of a shed workshop office kind of a situation. I just picked this off the web.

These and similar structures are usually insufficient or badly insulated and ventilation offers not much improvement. If I wanted to get the temperature inside to ambient shade temperatures how much would it cost and what would I use to achieve this?

The question should really be: how can I work out what power an air conditioner would consume if I wanted to drop the inside temperature from 42deg. C to say 26deg. C.

Or, if I could reduce the temperature by 6deg.C, by insulating, how much power would it require to get it from then 36deg.C to 26deg.C.

I am sure that there is a better way of explaining what I am after but like I said in the beginning I don't know much about it at all.

See what others have to say, I hope.

Thanks for the reply, Ky.

Hi Ky, I need some measurements, also the wall composition, and the roof. What is in there that produces heat? How airtight is it? One story or two? Will you be standing or sitting - if you want the last drop out of it. White or silver should help a lot. How many people in there and what kind of work they do? Windows? Side? Heights - size? Now I understand why the calculator.

Yep, that's why I need a calculator so once I know the volume of air to be turned over I can determine the power consumption. Not only for one size but for any. How do the Wall-marts of this world work it out or are they not air conditioned?

Doh!

The strength and profits come from very high ceilings, so that the heat is high up and exhausted, Some have a lightweight isolation to eliminate the direct heat radiation. And under that heat zone they work the AC, that falls down unto your head where you experience the comfort zones. The Saint Peter Basilique in Rome is also cool because of the high ceilings and dark windows but also in winter to heat it. The big boxes tend to switch to chilled water systems. Our bubble gum factory in Flanders had a big lake and 10 heavy water cooled 60 kVA Lebrun AC compressors and on hot summer days not enough cooling capacity. We kept the roof sprinkled with water and had some gain from the evaporation heat extraction. Was good for 4 degrees Celsius on a flat bituminous roof. Ceiling there was about 6 meter.

Thanks again for the information. I hope to be able to show some results here one day. You might be surprised about my approach to solving this.

Good to be and find help here. Have a great day, Ky.

A peak vent is good for a few degrees

I suppose that you have too much humidity for evaporative coolers?

the combination of low mounted evaporative coolers & peak vents is effective

The coolers also filter out dirt & pollen

Shade and breeze under the shade is good. If the shade system is dark, it should be at some distance from the roof to limit radiation. Trees do a good job too. You would be surprised how much heat your attic pushes down, even with some ventilation in it. 1500 - 2000 Watts per square meter in the sun is a big heat source. When you want to use Styrofoam outside and cover it with a light crete, 5 inches will be help you only a little more than 2 inches thickness. 2 inches is easy to handle and to attach to your steel structure. Before the styro turns yellow you can reinforce the outside with a mortar coat and fiber mesh. A few millimeters is enough. I made that mortar with ciment, sand and limestone dust (saves you the so wrongly called -mortar ciment) I added a plasticizer- you can also use acrylic base. The top coat I made similar with white ciment, fine sand and again the dust. I colored it "en masse" to never have to paint it again. This coating I applied with a rough sponge. It cover a lot of imperfections. When you roughen the styrofoam with 10 grit sandpaper or an old wood saw, that coating never comes off. A 5 gallon bucket crete costs about $50 here and my product only $6. I am testing a similar concept to hard coat the drive way.

The shade sails I use are coolaroo and reduce the heat with about 10 degrees Celsius when in the sun. These are perforated fine knotted and let the hot air escape and still provide some sunny experience. That happened to be a very good buy. Your heat comes from outside and that is the best place to isolate. The inside foam only prevents the cold energy to be absorbed into the walls. If this is useful, my pleasure.

Also, the level headed Australian's drool runs up his cheeks to his forehead. Right?

Not here on Magnetic Island. We have gravity fully under control

Ky, having done the steel shed studio/workshop exercise, I'd forget the styrofoam in the island climate and workshop context.

Have a look at these people and their various products and data sheets

parent company http://www.martini.net.au/

product arm & page you probably want to start at http://www.polymaxinsulation.com.au/thermal_commercial.html

roof side of things (another arm) http://www.reflectiveinsulation.com.au/

Also give some thought as to how you get light in, as this will affect the end AC picture.

And obviously you want a category 3 certified construction, inc paperwork for council. Many of these 'sheds' are not Cat3, and/or paper and upgrades are 'extra'

Thanks.

I'll PM you one of these days. There is more to my project than meets the eye.

Have one on me, Ky.

I'm sure it's all very 'hands on', or colour on, in your case

Consistency is the last refuge of the unimaginative.

Very cold, not hands on at all but it could be colorful. Maybe next week. Gotta have a few things in place.

We had a small 5.4 earth quake here yesterday. No drama but still a bit scary. We are just like ants in the end.

See Ya's, Ky.

for what it is good: a whole page full of links to calculators. I didn't find no really complete ones yet. For when you have some time:

http://www.google.com/search?client=gmail&rls=gm&q=AC%20calculator

Respectfully. D

Your search - http://www.google.com/search?client=gmail&rls=gm&q=AC%20calculator - did not match any documents.

Not much joy out of that one. I'll try a bit more now and see what I can find. Thanks for your help, Ky.

Try this: http://www.google.co.uk/search?q=AC+calculator

(the bit about gmail and rls may've been upsetting your browser/OS/whatever).

Bulls eye John. I can be on my way now. Just what I needed.

Thanks, Ky.

John

After having a closer look it fails to include any temperature, time in put. It does help to get the basics but I need a bit more detail. Nice try though, Ky.

I know bugger-all about AC - I've just been trying to get other folk's links and pointers working.

Cheers,
John

I appreciate it, thanks John. See how I go with this one, Ky.

I installed something the other day and found chrome on my computer, after the event. Sneaky little Bart arsed. Bloody worse the spam.

With all the help I am getting here it will take a bit to sort things out. Another day another program I suppose. A pity they don't come with a bucket of time and a tutor.

Thanks to all, Ky.

ACCA has treated the subject of commercial (Manual N) and residential (Manual J) heat and cooling load calculations better than anybody else I know. Many good softwares are based on their methods. As good as they are, they are expensive.

Thanks Coldspot

I tried to Google but to many others with that abbreviation. Added a few other leads but nothing. Could you give me another hint please?

Have a good one, Ky.

Think Coldspot was referring to http://www.acca.org/

I apologize for my acronym affections. Life has become complicated since the computer geeks started overwhelming us, the kids texting, like the military never could.

ACCA is the Air Conditioning Contractors of America. A lot of heat loss things were not clear until I started studying their manuals. They are thorough.

Hi Ky,

my son is an energy systems technologist.. he gave me the link to this downloadable system of calculations for building energy stuff... its free and a trusted source.. I don't know how to use it, but there seems to be training stuff available on the site... I'll forward your link to him, but I know he is busy.. so I can't hope for much help.

http://www.retscreen.net/ang/home.php

good luck.

Chris

Thanks Chris

This could take a while for me to be able to handle but it looks like it will do the job. Just the download took a while but it seems worth it. I'll try it when I am a bit fresher tomorrow. Looks good so far, Ky.

I can solve your problem but I want the following data :

A. Building wall thickness (all sides) and material of wall (you said steel ?)

B. Windows and their thickness and build (whether single sheet glass or some thing else, and what thickness)

C. Volume is 500 M3 but what is the expected flow of air in CFM or cubic meter or litre per minute (or per second).

D. In case alu foil laminated insulation (which is generally XPE Foam) is used, what is the thickness and what percentage of area has been covered.

E. As you rightly asked, what is the ambient temperature and also what is the solar fall on roof top. Also, what is the wall area in which direction and where exactly is the building located (e.g. in Asian countries it will have always more solar fall on North East and Nort West sides of walls, but it will be opposite in Australlia !).

F.. What is the expected temperature required in side.

Alos, there are other data required for example what is the heat load in side the building. In case there are some heavy machineries running, the Air Conditioner tonnage (TR) shall be much more. If it is an office, while heat load of humans (which is approximately 2 to 3 persons per 100 sq feet) is not much, 'fresh air circulation' is a must because oxygen percentage at no point of time should be less than 18 % in the air. Then fresh air replinishment shall enhance the load. However, to reduce this load there are other mechanisms. If it is a flat / large residence with little human density (hardly 1 person per 100 sq feet area), then 'air replenishment load factor' is not big and can be ignored.

And your questions are very very valid, and need answers. Only thing is, so many so called experts do not ask questions like you did (these questions do not even crop up in their minds) and hence they keep giving wrong solutions most of the times.

Note : A problem of one time shall be solved by our company free of cost. For detailed problem analysis and solutions, the cost needs to be compensated.

SPA Associates is in energy conservation consultancy of high rise buildings with high human density. We can save 40 to 50 % energy consumption of high rise buildings by different technologies developed and evolved by our engineers.

We are perhaps one of the first companies who have started such a novel approach, and we understand your need of energy savings for economics, besides environmental aspects.

Regards,

For SPA Associates

Ashok Shukla

Working Partner

Phone +91-9810145598

email : spa.associates@hotmail.com

good to meet you Ashok

Thank you for your generous offer, I really appreciate it. By now I can walk (know a little bit more) and soon I'll be running.

Note : A problem of one time shall be solved by our company free of cost. For detailed problem analysis and solutions, the cost needs to be compensated.

Even more generous. I might encounter this or similar problems in the future so I would like to know how to run unaided one day. If my ability to understand these complex matters fails me, I will get back to you and will take advantage of your companies services. In my case it will be a one fits all situation, or so I think.

Good luck, Ky.

to find the difference between reflective and black roofs, I use the following online calculators:

low slope calculator

steep slope calculator

you will have to get creative on the location selectors to find similar heating and cooling degree day data

the site has other link to calculators as well.

Very helpful GH

Because I'm here in Australia (Far North Queensland) I chose San Antonio as a similar location. I suppose it comes close to what we experience here when it comes to climate.

One thing is for sure, I will never regret becoming a member of CR4. Sucking brains here is like taking lollies from babies, I love it! At least now I know the general direction and can make my journey a bit faster from here.

Thanks for your input, Ky.

Thinking about your building, if you were to have it built and want to heat it I would recommend particular attention to sealing the so-called 'building envelope'.

Builders of that sort of building are not likely to be truly attuned to the realities of infiltration of outside ambient air. Thermal loss due to infiltration is driven by two major forces: wind and natural draft.

Thanks but we never need heating here, ever. I am on the right track now, just needs a bit more study and then a bit, Ky.

Heat only wears you out - The cold is truly painful.

Anticipating cooling loads are harder than heating. First you have the sun waving around in the sky every sunny day, then you have that latent load. Removing moisture is where the work really comes in.

Infiltration is a real issue with the wind. On the upwind side you have high pressure, and on the leeward low pressure - it just sucks the inside air right out. Building envelope tightness is real important.

Your picture has a deep blue color. Do you could live with a white building?

I wanted to give you some insights that will compliment the numbers you do with heat load calculation. Up here in Minnesota we fight the cold. Unlike heat, you have no choice.

Thanks, very considerate, Ky.

Consult a HVAC contractor.Here in the States, they are required to consider all the factors you mentioned, and others,plus degree days avarage for your area.They must perform these calculations to pass a board exam for license.

Oversizing a Air COnditoner is very inefficient, because they do not run long enough to remove moisture form the air.The result is you must set the thermostat lower to achieve the same comfort level.The best design is one that runs almost all of the time, but can eventually achieve cutoff on the hottest day.Sounds contrary to popular belief that bigger is better, but in this case, just right is better.

That is why a calculation must be properly performed to get the best results, else you could just oversize everything and waste energy.

Thanks

That's exactly what started me to research this area a bit more. They always want to sell, deligate the biggest units, understandably. I had my suspicions that something was not adding up or not being considered, hence my inquiry.

I will keep on using the tools that were supplied to me here but it is very complex and tedious. Stubbornness not only saves money but brings knowledge and will set me free. It will take a bit longer and I have already achieved a better understanding of these complex issues.

It reminds of a blond going to a car yard and kicking tires. When I meet my sales person I would like to be "in the know" and maybe tell him to stop feeding me crap. Thanks for your assistance, very helpful, Ky.

I know this one, you want to know enough to sift through the bullshine that is the stock & trade of salesman

Yep, the donga's of this world Mate. If I could only learn faster than I can think. It's so good to have CR4 as a filter and be surrounded by decent guys like you and others here and in other threads.

We shall see what comes out of all this. Very encouraging to say the least, Ky.

Aw Shucks

twern't nuttin

Be nice to sales guys, they bring donuts.

Rereading your initial inquiry, I see your interest in exterior coatings - which are very important.

Do not underestimate the latent load of a building in a coastal region - a load imposed by infiltration.

It would seem to me any credible heat load calculation and operating cost analysis would require thorough investigation of dehumidification factors, and they will possibly be greater than the sensible loads incurred by the suns thermal radiant energy. Especially since dehumidification will be required 24 hours per day, 365 days per year; and opaque panel loads are peak loads occurring once per day, and only during certain times of the year.

It is the part-load efficiency that is costly - you can usually get through the day if you willing to tolerate some temperature excursions.