engineering knowledge required :p -> water heater/air ????

[JinMTVT]

nothing to do with audio
but as i figure some of you guys are really smart,
and i thought that you might be able to help me out!

I want to heat my buisness ( garage + office of approx 2100 cubic feet )
with a water/air system

using the following :

http://www.tanklesswaterheater.ca/seriesthree.html

in a closed loop water system
controlled by a thermostat

the thermo would make an electrical pump
start at a flow that would be good for the heater to work with ( probqably near 3.0g/min )

then water would then be heated by the EEmax tankless heater by a certain margin ( i was told that it can go as high as 180F when using already warm/hot water )

it would then go trhought 2 to 5 big car radiators inside a casing ( i am reusing theold oild furnace system case and fan .. )

and then go back to a high mounted reservoir where the pump would take the water to go in

my point beeing that in Quebec electricity is really really cheap compared to fuels
then it doesn't raise as the fuel cost does
( be it propane or whatever, they all follow the same curve ...UP )

so i figured out that using a 99% ( or near that )
efficient heater with minimal loss in the system ( plastic piping, no tank to heat .. probably 5-10% max of losses)

and high efficiency heat exchanger due to the big surface of the radiators ...

it could be pretty economical i think

what do you guys think ?



i believe ( in my humble brain ) that what will not be exchanged to the air ( talking about energy ) will be going back into the system with minimal loss
taking less power to heat up to max temp again

so there should be a good efficiency of the total system


i need as much input as possible on this subject please!
as i am starting to buy and isntall this system
( gettting REALLLLY cold now here!! )

thanks alot for ur time

[BillH]

Hi JinMTVT, it's getting cold here, too.

How about using something like this?

[JinMTVT]

if i remember correctly

this kind of heating is not very efficient

then , i have like 2100 square feet to heat up

convection just doesn't cut it

thanks neway

[JinMTVT]

please if anybody else has any experience in that kind of setup , or the knowledged of the associated science!!


i'd need some input asap as i need to buy the hole system soooon!

[Ron E]

All (any) electric heat is 100% efficient, assuming the heating element is inside the space to be heated. The only reason to use a liquid electric system (IMO) is to have zones and for that you would need a complicated valving system.

Your kludged together system with car radiators and a tankless boiler may work fine, and you may spend money and have no end of trouble with it due to leaks, control issues, etc...

Consider how often it will cycle, consider the expansion and contraction of the fluid within the system. Consider how you hook up the (single pass) radiators and the flowrate of the system (both air and H2O) and you may get something that will work.

I'd just go with the baseboard.

[maxro]

Originally posted by Ron E
I'd just go with the baseboard.

And add a fan if you want convection.

[JinMTVT]

ok
basically what you guys are saying is that all electrical systems are 100% efficient ( or near )

with the price of electricity in quebec,
do you guys think that i should still consider 100% electrical system ?


minus the fan and or pump i guess ..



So you guys are saying that quality electrical heater with some kinda of convection ( either parabollic stuff or fan)
would give the same efficiency than my system,
and that the only diff of my system is that i can have a central heater that sends off to each rooms ?


if it is of the same efficiency then i would see no reason to install such a system at all ..electrical only would then be more than enough and probaly 100% trouble free


is there a way to measure cost of heating with Watts
or whatever other units
so that i could compare commercial fueled units Vs electrical units ?

thanks all again for your time
really appreciated!!!

[Ron E]

Your electric bill should have a number for kilowatt-hours (kW-h) and the cost per kW-h.

1kW x 1hour = 1 KW-h
100W x 10 hours = 1 KW-h

An electric heater for a home will be many kW.

A parabolic reflector is a radiant heater - it is for heating objects rather than the air. While these work as supplementary heat, they are not useful for space heating. They are also somewhat of a fire hazard.

In MN, the cost per kW-hr is something like 9cents
If I had a 5kW heater running 10 hours a day, 31 days a month, for 5 months = 5*10*31*5=7750kW-h
=$697.5 at 0.09 per kW-h

5KW = 17060 Btu/Hr = 18MJ/hr = 0.17 Therms/hour
0.17*10*31*5=263.5 therms, but say you have an 85% efficient furnace - that means you need to buy 263.5/.85=310 therms of gas

In MN, gas costs around $1 per therm
So the same amount of heat will cost $310 using gas.

So at least in Minnesota, gas is much cheaper, If I didn't mess up the calcs.

Now you need to figure out how much heat you need......
http://www.acdirect.com/new_faq/info...furnaces_1.php
...probably more than 5kW. Maybe more like 20kW.... But this calculation is best left to a professional.

Good luck.

[JinMTVT]

last time i checked ( few years i think )
it was in the 4.3c kw/h ( CAD$ )

and we have the higest price around for all types of fuels in N.A.

Then, i believe that electrical will give me more control with multiple installations than 1-2 fuel heaters would do

Would it be wise to combine different type of electrical heaters ?

like a few baseboard with a fan heater that uses different thermo sensors ?
i have access to pretty sofisticated auto heater controls/thermos ...

[JinMTVT]

ok did some reading ( thanks for the link )

taking the 50btu/square' gives about 125 000btus needed ( wich will never be the case since i won't be heating everything at confortable temp and at all times )

then 125 000 / 3400 = 36.7KW

at 0.05$ for 1KW = 1.83$ for 1 hour

so roughly 1300$ / month
( that would be at maximum power all the time )

i'd say that it will never run at more than 25-35%
since during the night i can do down to probably 10-15C
everywhere using programmables....
and will be working part load for the day cycles

so would give about 350-400$/month

wich is a bit less than what i used to pay for the oil in the furnace ( roughly 450-500$/month durin hard winter)
and my furnace was probably 25% less efficient than modern oil stuff ..so we are in the ballpark

then the installation will cost pretty much near nothing compare to a new fuel heating system
and i will depend 0 on the fuel companies
and i will make 1 million times less pollution
( since electricity is almost 100% non polluant in Quebec!!!! )