h is called the heat transfer coefficient. It is an interesting little thing that differs between the materials you are using. It partly depends on the velocity the substance is moving at or the air is moving towards the substance at. Also, it depends on geometry and sometimes temperature.
There is no specific way of finding the heat transfer coefficient of something. It is usually found by doing experiments. One of my roommates is working in a lab that is looking for the heat transfer coefficients of various substances. She is excited that I am learning about it.
h is used in as equation for finding the heat transfer of a convection process.
Q = hAdT
Q is usually written with a dot over it, but it is difficult to do so in a post. It is the heat transferred per time. A is the surface area of the substance that is exposed to the convection. dT is the change in temperature of the substance, from its initial temperature to its final temperature after losing or gaining heat. "Change" in something is expressed by the Greek letter delta, but there are no delta's on my keyboard, so I used a "d". It is not quite the same, but similar.
Now I must return to my studying. My exam is tomorrow, so 'tis imperative that I understand these concepts.
