The GEOTERM.PRO airhydroaccumulators is a sealed vessel with cocks at the lower and upper points, partially filled with thermal. The air at the top acts as an expansion tank, the thermal fluid at the bottom feeds the system when the air escapes.
The level of the thermal fluid inside the airhydroaccumulator changes when the air exits the hydraulic system, or when the pressure in the system changes. The walls of the air accumulator are semi-transparent to visually check the level of the thermal fluid, and airhydroaccumulator are sometimes called "level vessel".
Application example of airhydroaccumulator with BOX-IN2 geothermal manifold box and geothermal heat pump:
The GEOTERM.PRO airhydroaccumulator replaces three devices:
|1.||Automatic air vent. Conventional automatic air vent valves sometimes drain the heat transfer medium from the hydraulic system due to fine sand getting under the valve seat, leading to accidents. The airhydroaccumulator does not have this disadvantage.|
|2.||Expansion vessel. In a conventional expansion vessel, the rubber diaphragm breaks down over time, causing accidents. The airhydroaccumulator has no diaphragm and such problems occur.|
|3.||Maintains pressure in the hydraulic system. When a normal hydraulic system is vented, the pressure in the system is reduced and the system stops working. Installing a conventional automatic make-up solves the problem, but if the system leaks, it leads to flooding of the premises. The airhydroaccumulator does not have these risks.|
When starting up a geothermal system for the first time, we recommend a procedure
|1.||Close the ball valves at the top and bottom of the airhydroaccumulator;|
|2.||Fill the geothermal system with antifreeze, bleed as much air as possible from the system by pumping the individual loops in turn;|
|3.||Open the ball valve at the bottom of the airhydroaccumulator;|
|4.||Raise the antifreeze pressure in the geothermal system, this will reduce the air volume in the airhydroaccumulator and raise the antifreeze level to approx. 2/3 of the air hydraulic accumulator.|
If the antifreeze level has dropped critically:
|1.||Close the ball valve at the bottom of the airhydroaccumulator;|
|2.||Open the ball valve at the top of the airhydroaccumulator, top up the antifreeze to approx. 1/2 of the airhydroaccumulator;|
|3.||Close the ball valve at the top of the airhydroaccumulator;|
|4.||Open the ball valve at the bottom of the airhydroaccumulator.|
When the antifreeze pressure in the geothermal system drops:
|1.||Start the antifreeze circulation pump;|
|2.||Close the geothermal loops feeding antifreeze on the airhydroaccumulator, this will create a discharge in the airhydroaccumulator and the antifreeze level will drop. Bring the antifreeze level in the airhydroaccumulator to a minimum;|
|3.||Close the ball valve at the bottom of the airhydroaccumulator, open the ball valve at the top of the airhydroaccumulator and top up the antifreeze;|
|4.||Close the ball valve at the top, open the ball valve at the bottom of the airhydroaccumulator. Repeat points 2 to 4 if necessary;|
|5.||Switch off the antifreeze circulation pump.|
GEOTERM.PRO airhydroaccumulators are installed at the highest point of a heating or geothermal system. Operating conditions for GEOTHERM.PRO airhydroaccumulator:
- temperatures from minus 12 to plus 60 °C;
- pressure up to 5 bar (short-term pressure increase up to 8 bar is possible).
For a geothermal system, the choice of airhydroaccumulator or expansion vessel depends on the volume of the geothermal system, the operating temperatures and the composition of the heat transfer medium (antifreeze).
Approximate volume of the airhydroaccumulator: