Heater - Heat Exchange Questions:

[DIYSer]

I recently acquired a few things that I'm hoping I can use to build a heater for a small area (10'H x 12'W x 12'L).

Things I current have:

1. 20 gallons of used motor oil.
2. An old 5200 BTU window AC unit. The blower components work, the coils are 'supposedly' good, but the compressor is bad.
3. A design for an oil burner + boiler

I've got a few problems that I need some help solving:

1. I want the blower discharge air temp to be 125 degrees F. That obviously means my boiler water temp must be higher--but how much higher (145-165 F?). How would I calculate the ideal water temp so that I can get the temp I want to come out of the system?

2. Assuming I don't need a water circulating pump, how can I then calculate the boiler water flow rate at the water temp solved for in Q1 (above)? If I do need a water circulating pump, how would I calculate the ideal water flow rate to achieve my desired output temp?

3. How would I calculate the ideal capacity of my boiler tank so that it contains enough heat to maintain a continuous heating for at least 45 minutes?

4. How would I then calculate the heat transfer rate between the boiler tank & the combustion chamber?

Thanks in advance for any help that you can provide.

p.s.:

- The AC evaporator coil uses 1/8" diameter copper tubing
- The dimensions of the evap coil are: 7"H x 13"W

 

[Future Bruno]

x 16"L- The room is insulated with R-19 fiberglass- The combustion chamber will be made of 6" (inner diameter) x 12" (long) black steel pipe.