Heating a garage?

I would like to be able to heat my garage 12 feet wide by 24 feet long built from concrete blocks with Solar power. Is that possible?

Yes, you can make an 'old engine oil ' furnace.
Its efficient and not hard to do.
Google it.

John C Daley wrote:Yes, you can make an 'old engine oil ' furnace.
Its efficient and not hard to do.
Google it.

Great idea and I intend to make an oil burner furnace for my garage one day, but I don't think that is the solar solution the OP is looking for.  Heating with electricity can be done, but it will require extra solar panels and possibly a larger battery bank if you need to heat after sundown.  If you need to heat every day it will be difficult to recharge the batteries while using the heater unless you have plenty of solar panels.
EDIT: consider installing foam insulation sheets inside the concrete blocks to help keep out the cold and hold in the warmth.  They make a huge difference.  I installed both 1/2" and 2" foam on different parts of the cement wall on my home and according to the infrared thermometer the difference is anywhere from 10* to 15* warmer in the winter months compared to the bare wall.

Of course you can.  Will it be economical is a completely seperate issue.  More information needed.  How is the garage built?  How is it oriented to the sun?  How is it insulated?

Your mentions of an oil heater brought back memories of Korea and one of the duties I pulled was night security at the residence of the GOC General Decker. Patrolling the area in Winter was very cold so we were allowed to step into the building where the oil heater was kept and it was beautifully warm. There was one fault in that the dam thing used to go, "whoomf" every so often which made me jump. I'm finding that Solar Power is more complicated that I realised and installing oil heating in England is really expensive so I'm looking into the feasibility of taking a spur pipe, suitably insulated from the house but its all in the mind at the moment.      

The new heaters and the home made ones do not have that problem.
Here is a manufactured one waste oil /multifuel heater

Kroll heaters

Another multi waste oil

shed built

Since the garage is already built running tubes in the concrete is out though tubes could be run into the walls of the west side of the garage. When the sun heats up the west wall these tubes would also heat up. These tubes would be filled with air or water.  Is this something like what you were thinking?

Here are some threads that might be of interest:

https://permies.com/t/140817/idea-solar-water-heater-decent

https://permies.com/t/107919/care-share-passive-solar-air

https://permies.com/t/139451/Solar-hot-water-problems-love

A solar air heater is the least costly solution for heating a building. A fan top and bottom controlled by a differential thermostat with flaps to prevent the heat from siphoning off at night. You do need good sun though. I would not want to rely on it for sole source heat but it could help offset the cost of heating. Insulation will be key of course...
Cheers, David

Insulation
Without insulation you will be fighting a losing battle. You can think of this as part of your battery.

Heat Pump
You might be able to use a heat pump to get a 3x multiplier for the solar electric that is being used

Radiant Heating
You could run pex water pipe/tubing in the floor
Or you can run electric wire in the floor that operated like a heating with a simple controller

Battery Bank
You can have a tank with hot water that is storing solar thermal energy
You could also store the heat in the floor too or some type of mass
You can also capture solar electric in a regular battery and then create heat at night.

Solar Gain
You can power your system by solar electric or solar thermal panels. The panels cost about the same per watt to buy, but solar electric take up more space, and most important you can also DIY solar thermal pretty cheap if you dont want to buy a system.