There is a point at the center of the palm cal Lao gong or Palace of Toil. In acupuncture it is said:

Clears heat from the Pericardium and revives consciousness
Clears heat from the Heart and calms the spirit
Harmonizes the Stomach and clears heat from the middle jiao
Clears the nutritive level and cools blood

As you practice sensations will come and go, it is no big deal. The why is not so important. In general heat is healing and tingling blockages opening.

I do not know if energy inherently flows in circles but I seems to behave a lot like water. The human body is most efficient when it moves in circles and not in abrupt angles.

Ken

Greetings -

You may be interested to know that there is a scientifically measurable effect to the chi emission in your palms, in terms of infrasonic waves. I discuss this in one of the lessons of my online Tai Chi mini-course. Here's a direct link to that lesson:
www.cloudwater.com/intro/mi...Power.php

When we talk about circular motions in Tai Chi, it really has nothing to do with how energy flows. Energy can flow in any pattern. If you look at the four main Tai Chi energy elements (peng, lu, ji, an), only one of them has a distinct circular pattern.

It's interesting that many Tai Chi limb movements "appear" more circular than they actually are. I attribute this to combining limb movement with torso, hip, and/or waist turns. In other words, while the performer may be performing and essentially linear arm movement (for example, those that express ji energy), the turning in the torso may make the arm movement appear more circular to an outside observer.

Best wishes,
Al