Final answer:
To improve the efficiency of a fireplace or high-efficiency gas furnace, external air supply for combustion and a convective loop to distribute heated room air evenly can be utilized.
Step-by-step explanation:
To maximize the efficiency of a fireplace or high-efficiency gas furnace, we can use two methods involving the principles of air and heat transfer. Firstly, an external air supply can be used for the combustion of fuel, which brings fresh oxygen from outside to support the combustion process, ensuring a more complete burn and reducing the amount of heated air drawn from the room. This is an effective way to enhance the efficiency of fuel usage and reduce heat loss.
Secondly, a method involving convection can be employed by circulating room air around the outside of the firebox and back into the room. In this system, commonly known as a gravity furnace, the air heated by the stove or furnace expands and rises, forming a convective loop. This hot air transfers energy to other parts of the room, and as it is cooled at the ceiling and outside walls, it contracts and sinks, creating a cycle that evenly distributes heat.