Quick start

One application, three modules - GLN Analysis is one of the three modules of the Analysis Suite, which are installed together and share a single window. The three buttons at the left of the toolbar switch between them, and the button that is lit tells you which module is active:

• TRT — interpretation of a thermal response test, which measures the ground properties the design relies on.
• GHE — design and simulation of a ground heat exchanger field.
• GLN — design of the hydraulic network that connects it, the subject of this manual.

Switching module rebuilds the analysis tree, the panels and the console; the window shown in the figure below is the GLN one. Each module is licensed separately, and the licence that applies is that of the active module. The project sheet is shared by the three modules, so a project keeps one identity. Panels shared between modules, such as the heat carrier fluid, change meaning with the module and have their own help page.

The three modules also follow one another: a thermal response test interpreted in TRT gives the ground thermal conductivity and the borehole thermal resistance used by GHE, and the borehole field designed in GHE is then balanced hydraulically in GLN. Each module can also be used on its own.

Activating a professional licence - GLN Analysis runs in demonstration mode until a valid licence is loaded. In that mode a sample network is loaded so the module can be explored, but the drawing is read only: the palette places nothing, the property editors and the tables are frozen, and nothing can be saved. The solver keeps running, so the results of the sample network stay live. To activate the professional version, open License Agreement from the main menu and accept the end-user licence agreement. This opens the Licenses panel, a table listing every module of the Analysis Suite with its current status — Licensed, Demo, or Expired — and, once licensed, its expiry date. Click Open .lic file… and select the licence file received after purchase: a licence activates the module it was issued for, and a Suite licence activates every module. Licences are available at gheanalysis.com. The licence is validated online each time the software starts; a short offline grace period keeps a previously activated licence working if no connection is available, after which the module falls back to demonstration mode.

A first network in a few minutes - The simplest way to build a first network is to follow the analysis tree from top to bottom, since each node sets part of what the next one needs.

1. Project description - record the project, the client and the site. This information travels inside the network file.
2. Heat carrier fluid - select the fluid and its antifreeze concentration. It sets the density and the viscosity used in every pressure loss.
3. Pump curve - the five pump slots already hold a usable ladder of curves, from a small residential circulator to the primary pump of a commercial field, so a first network solves without touching this panel. Replace them with the manufacturer H-Q points, and the hydraulic and motor efficiencies, of the pump you actually intend to install before quoting a result.
4. Hydraulic network - draw the circuit, give it its properties, and place the pressure reference:

• Draw the circuit - place components from the palette and connect them with pipes. For the ground heat exchanger itself, use the Network Builder rather than the mouse: choose the probe type, the connection scheme, the number of boreholes, the spacing and the depth, and the whole field is generated at once.
• Set the properties - give each pipe a type from the library, which fills its diameter and roughness together, and check the elevations. Then type the real length of every pipe. A freshly drawn pipe only carries a seed length, one metre per grid square, and a network solved on seed lengths looks normal while being wrong. The Length column of the Pipes table flags these pipes with a small orange bar; see Pipe length in the Hydraulic network chapter.
• Place the pressurization point - an expansion vessel, a reservoir or a fill connection, marked as the fixed-pressure node. A circuit without one is still solved, anchored to the Static pressure of its Network entry, and the console names the node it chose; place one yourself to choose where the pressure reference sits.

1. Read the result - the network is solved as you draw, with no button to press: the tables fill in, the drawing takes the colours of the display mode, and the four console pages report the pump operating points, the design checks, the critical head of each network and the conservation check. If the solve does not converge, no results are shown and page 4 of the console gives the reason.

At any step, the help button gives guidance on the current panel, and the same content forms the chapters of this manual.

Before you begin - Four inputs decide whether the results mean anything. The pipe lengths must be typed, since the drawing carries no distances. The fluid must be the one that will circulate, at the temperature at which it will circulate: an antifreeze solution near 0 °C is far more viscous than water at 20 °C, and the difference goes straight into the pump head. The elevations must be entered, since a borehole leg is mostly a hydrostatic column. And no closed circuit may carry more than one fixed-pressure node: two over-determine the loop and drive a flow that nothing is pumping. A circuit with none is solved with a reference chosen by the software.

A quick sanity check - A well-behaved ground loop usually shows velocities between 0.3 and 2.5 m/s, with the mains toward 0.6 to 1.2 m/s; friction gradients between 100 and 400 Pa/m; and a borehole balance ratio close to 1. A balance ratio well above 1 means some loops are starved while others are over-supplied, which is a piping problem and not a sizing problem. A friction gradient far above the window on a single pipe usually means a diameter one size too small, and one far below it usually means an oversized pipe carrying an unnecessary volume of antifreeze.

Panel layout and numerical input - The module reuses the resizable split layout of the suite. In GLN the lower row of the window carries the result tables on the left and the property inspector on the right, so the drawing, the numbers and the inputs are visible at the same time. Drag the dividers to give more room to whichever of the three you are working in. As elsewhere in the suite, numerical fields respond to the mouse wheel and to the ↑ / ↓ keys as well as to typing.