In laminar flow the fluid moves in separate layers. The current lines are parallel to the pipe axis even when velocity remains unchanged and has low values. The flow is turbulent when there is intensive rearrangement of particles because of the existence of cross and some other vortices of particles. The difference between these two types of flow is the fluid velocity. In laminar flow the velocity of the fluid is comparatively low. It was found that the transition from laminar to turbulent motion is not a gradual process but occurs spontaneously and at a leap. The Reynolds number is used to determine the difference between the two regimes.

To calculate this number we have to know the pipe diameter and the kinematic viscosity of the fluid. This is extremely important when channels, that convey air from one point to another, have to be estimated as well as for pipe networks, used to carry water or another fluid for the radiator heating system, water radiant, convector heating, etc. The velocity at which one of these regimes changes into the other is called critical or the Reynolds number is critical.

It was determined experimentally that all real flows with Reynolds number smaller than 2320 are laminar and if Re is between 2320 and 13800 then the two types of flow are possible. When the velocity of the fluid is greater than 13800, the flows are only turbulent.

Describe the difference between laminar and turbulent flow.
What does this mean to a potential customer who considers purchasing a Geothermal heating system?
To begin with, in the turbulent flow there is a bigger energy exchange between the fluid circulating inside the poly pipe and the ground itself. Additionally, more energy is required from the pump to circulate the fluid. But on other side you gain much more energy.
How the turbulent flow affects the interior duct distributing or hydronic distributing system.
Turbulent flow is unacceptable in most cases when you have forced the air distributing system. This will lead to loss of energy from the turbo machine (the blower). Moreover, the PV curve of the fan will not be at a satisfactory level. Instead of the image in Fig. 1, it will resemble the image in Fig. 2.
The static pressure can be read from Fig. 1 at 0,1 WC and down in the horizontal the Cubic feet per minute passing the coil are 1250 CFM. If that is a 3-ton Climate Master geothermal TTV model, the CFM requirements are 1150. In this case all design characteristics are met.
If the above characteristics are not met, the turbulence flow becomes much greater than normal. Consequently, a significant increase of the static pressure of the duct distributing system will occur and the preinstalled factory blower will not be able to keep up with CFM requirements, thereby causing the  decrease of the COP rating of the unit itself. Thus, the unit efficiency will drop, causing the thermostat to call in a very short time for a second stage and then for a third stage.
Thus, the biggest portion of energy will be consumed from the electric strip element.
A well-designed and installed system will not have the superfluous energy usage described above.
Below are some of the reasons for the appearance of increased static pressure and turbulent flow:

    Incorrect duct size, especially on the return side.
    Improper duct fittings attached to the main trunk line.
    Improper attachment of the main trunk line  to the duct plenum.
    If the sheet metal fabrication shop is not available to the installation firm, all necessary custom fittings can not be fabricated in order to minimize the turbulence into the distributing system.
    And many more

In the hydronic distributing system, the increase of turbulence is not the only reason for an increase of the energy bills. Another factor is the pumping power used to distribute the energy.

The energy gain from the earth throughout geothermal heating in Illinois may be up to four units. Distributing inside the home may get very tricky if a radiant system is used. Namely, if four units of free energy are being gained from the earth, improper design may spend instead five units of energy for inside-the-home distribution. This will eliminate all possibility of energy cost savings.

Conclusions:
In you are considering to hire a firm to install geothermal in Chicago land, give us a call. There will be no gassing or miscommunications. It will be a smooth process from the very beginning, the designing stage, throughout the last installation stage.