How heat is added to a system? Probably a noob question ok so I am literally just getting into thermodynamics, this is literally my first search, what I am wondering is how fundamentally heat is added to a system. For example say I have a flame heating an object at 120 degrees F and I add a second flame beneath the object that is also burning at 120 degrees F, does the total heat applied to the object equal 240 degrees F or is it still 120 Degrees F from a larger source. 
 A: No matter how many heat sources you use that are all 120 degrees F, once the object being heated reaches 120 degrees F, it will be at equilibrium with the heat sources and will not get hotter. 
A: As pointed out by @Alchimista temperature and heat are two different things. Temperature is a measure of part of the internal microscopic energy of an object. Heat is defined as energy transfer between objects due to a temperature difference between the objects. So to answer the title of your post heat will transfer to a system (object) if the system is exposed to something that has a higher temperature than the system. But once the temperatures are the same heat transfer stops.
Now everything else being the same, the rate of heat transfer to the system in the cases of heat conduction and convection will be proportional to the magnitude of the temperature difference. So if you double the temperature difference between the heat source and the system you will theoretically double the rate of heat transfer.
Generally, depending on the mass of the system and the heat source, and assuming no system phase changes and no system work, as heat transfers to the system the temperature of the system will rise and the temperature of the source will fall until eventually they both reach the same temperature somewhere between their original temperatures. The two objects are then said to be in thermal equilibrium with each other and heat transfer ceases.
Beyond that if you are really interested in learning more take a course and/or get a good textbook on thermodynamics.
Hope this helps as a primer.
A: Internal miccroscopic energy of the system is stored in particles kinetic and potential energy. So if object is bigger it has more particles and so every inidividual particle needs to move slower to have the same amount of total kinetic energy. Energy per particle is directly connected to temperature. So when an object is at 120 degrees and the other object is at 100 degrees it means they will exchange their internal energies but the one at 120 will give more of its internal energy then it receives. Tempreture also can be thought of as readiness of an object to give away its internal energy. Part that is being transfered is called heat. An object which does not give away any heat and can only receive is said to be at absolute zero. So, if you have two flames each at 120 they will heat an object two times faster but to a 120 degree at which point readiness of that object is equal to readiness of your heat sources so the object gives away about the same amount as it receives. So no more increase in internal energy or temperature.
