Console & dashboard

The console gathers, in one place, the design-level indicators of the system and the health of the simulation that produced them. It is organised as four independent pages, reached with the buttons at the bottom of the panel, and the four share a common footer reporting computation times and the convergence of the solver. A fifth page reports the annual energy cost; its button appears when the Energy Cost module is active.

The console doubles as the help viewer: clicking the help button of any panel replaces the results with the help page of that panel, and clicking one of the page buttons below brings the results back. Selecting a node in the analysis tree changes the panel on the left, not the page shown here: the page you last chose stays until you choose another.

Page 1, demand coverage - Reached with the Demand coverage button. Reports, for cooling and heating separately, two blocks of five rows, each closed by its total: the heat pump output, the geocooling supply, the auxiliary contribution, the domestic hot water made and the uncovered demand — first at the peak hour in kW under Total peak, then over the year in MWh/y under Total energy. This page answers half of the central sizing question: what serves the demand, and what is left unserved. The three coverage ratios that state the same thing as percentages live on page 3, under Demand coverage ratio.

Each block is a whole and its parts. The five power rows are read at the same instant — the hour when the building asks for the most, space load plus domestic hot water combined. That instant is named on the Thermal loads panel, whose summary opens with Peak hour: an index into the load profile, one per mode, sitting next to the profile it points into. The cooling peak and the heating peak never fall on the same hour. The first four rows here are what the system delivers then, the fifth is what it does not, and the five add up to that peak demand exactly. The energy block does the same over the year. Each block's last row is that whole: Total peak is the demand at that hour, Total energy the demand over the year — the same two figures the Thermal loads panel reports as Total peak, and as Space energy plus DHW energy.

Geocooling is its own row in both blocks, and that is a statement about which machine did the work. When the compressor is bypassed, the cooling delivered is the borehole field's, not the heat pump's; counting it under Heat pump would name a machine that is switched off. Both rows read — in the heating column: a geocooling loop cannot heat. They are also what makes each block close on such a project — without the energy row, the cooling column fell short by the entire geocooling supply.

Reading the power block against the load panel. On a project without domestic hot water, the four rows sum to the Space peak of the Thermal loads panel — the same maximum of the space load. On a project that declares hot water — the separate load format — they sum to that peak plus the hot water drawn at that hour, and the Domestic hot water row states how much of it the system actually makes. A hot water row well below the demand is a shortfall in the same kilowatts as Uncovered demand, and the two travel together.

The peak-hour row and the annual total for hot water are read at different hours. In heating, hot water draws on whatever heat pump capacity the space load leaves unused, and the peak is the hour when space load is highest — usually the coldest hour, with nothing left over. The rest of the year, when the space load eases, the heat pump makes it, and that is what the annual figure sums. A project can show it plainly: at its heating peak the heat pump and auxiliary together drew 225.8 kW of the hour's 1243.9 kW demand, hot water read 0.0 kW, and the shortfall showed up whole in Uncovered — yet the same project's Dom. hot water total for the year came to 47.1 MWh/y.

What the peak hour is not. It is the busiest hour for the building, not the hour when the system delivers the most. The two coincide while everything is covered; once the system saturates its output goes flat at the installed capacity and it delivers that much over many hours, none of which is necessarily the demanding one. The page deliberately reports the demanding hour: it is the one a design has to answer for.

Three coverages, because a single one cannot separate different shortfalls (all on page 3). Space coverage counts the heating and cooling load alone; DHW coverage the hot water alone, and reads — where none is asked for; Total coverage adds the hot water to both sides of the ratio. When they agree, the system serves every demand in the same proportion. When they part company, the difference is hot water the system does not make — DHW coverage puts a figure on it directly, and Uncovered (MWh/y) on page 1 states it in energy.

A geocooling design shows this at its sharpest. The compressor is bypassed in cooling, so the condenser produces no heat to recover and no hot water is made during those hours: Space coverage can read 100 % while Energy coverage reads half that. Nothing is wrong with the borehole field — the missing energy is an auxiliary water heater to specify, and DHW coverage reads zero while Space coverage reads 100.

Page 2, energy consumption - Reached with the Energy usage button. Reports the total system peak power demand (kW) and the mean annual electricity consumption (MWh/y) for each component — heat pump, auxiliary equipment, domestic hot water, and circulation pumps — together with the combined system total. Use this page to assess the electrical load profile and evaluate pump energy relative to compressor energy.

Hot water has its own line, and it has to. The heat pumps make it, but not at the efficiency at which they condition the space: the space COP varies hour by hour with the entering fluid temperature and the part load, while domestic hot water is priced at the fixed COP entered on the Heat pump performance panel. In cooling the two are worlds apart — the water is heated from condenser heat that would otherwise be rejected to the ground, so its COP can run an order of magnitude above the space COP. Folded into the heat pump line, that electricity would be invisible and the line's implied efficiency would be neither of the two.

The energy lines add up; the power lines do not, and that is not a defect. Each kW cell is the maximum that component ever draws, and the four maxima fall at four different hours — the compressors peak when the building peaks, the pumps run flat, the auxiliary only at the extremes. Summing them would describe an hour that never happened. Only the Total line is a real simultaneous maximum, read on the system as a whole.

Page 3, system efficiency - Reached with the Energy efficiency button. Reports the seasonal COP of the complete system (sCOP), the seasonal COP of the heat pumps on the space load, the seasonal COP of the domestic hot water they make, and the reduction in peak electrical demand obtained against a resistive reference (%). Below them, the Demand coverage ratio block states as percentages what page 1 states in kilowatts and megawatt-hours: the share of the peak that is served, then the share of the annual demand — for the space load, for the hot water, and for the two together. This page answers one question: what does the system return for what it is asked.

All three coefficients are ratios of energies over the whole horizon, not averages of hourly values: the heat delivered divided by the electricity drawn to deliver it. That weights every hour by what it actually consumed, which is what makes the figure comparable to a utility bill. An average of hourly COPs would weight an hour at five per cent load exactly like an hour at peak, and since a system spends most of its hours lightly loaded — where part-load degradation is worst — such an average sits well away from what the season really cost. The three differ in what they count: the system sCOP includes the auxiliary and the circulation pumps, the heat pump sCOP counts the compressors on the space load alone, and the hot water sCOP counts the same compressors on the water they heat. A wide gap between the first two says the electricity is going somewhere other than the compressors — usually the pumps, which page 2 breaks out.

Hot water is on its own line because it is not made at the same efficiency. The space COP varies hour by hour with the entering fluid temperature and the part load; the hot water is priced at the fixed COP of the Heat pump performance panel, and in cooling that is recovered condenser heat. On a project drawing 197 MWh of space cooling at a COP of 3.00 and 274 MWh of hot water at 25.00, a single blended line would read 6.14 — more than twice the machine's real space efficiency, and less than a quarter of what the water recovery actually achieves. In heating the blend errs the other way, since hot water is made at a lower COP than space heat. Neither number describes anything you can buy, which is why there are two.

Both read --- where nothing ran: a geocooling system in cooling draws no compressor electricity at all, so there is no ratio to form, and the hot water line is blank where no hot water was produced. The hot water sCOP reads ∞ when the cooling DHW COP is set to ∞: the water is then pure condenser recovery and costs no electricity, so the ratio really is unbounded — the console prints the same symbol the panel accepted.

Peak demand reduction compares two peaks, and it is a heating figure. The reference is an all-electric resistive installation: a resistance of COP 1 draws, at its worst hour, exactly the peak thermal demand of the building. The line is what the ground-source system saves against that — its own peak electrical draw, auxiliary and circulation pumps included, subtracted from that reference and expressed as a percentage. Both terms are maxima over the whole horizon, each taken at its own hour, because that is what a demand charge bills: the reference peaks when the building is coldest, the heat pump when its own draw is highest, and those need not be the same hour.

The cooling column reads —, and always will. A resistive element heats; it cannot cool, so there is no reference to compare against and no reduction to report. A number there would be a comparison with an installation that cannot exist.

A negative value is a result, not an error: it says the system draws more peak power than a resistance would, which happens when a short field pushes the load onto the auxiliary and the pumps. Where it appears, the field length and the pump sizing are what to revisit.

Read it against Uncovered demand, on page 1. The resistive reference covers the whole demand by definition; the ground-source system draws less partly because, when it saturates, it delivers less. Where Uncovered demand is zero the two installations do the same work and the comparison is fair. Where it is not, the reduction is optimistic by roughly the power that shortfall represents — the figure is still what the two systems would actually draw, but they are no longer doing the same job.

Page 4, ground response and validity - Reached with the Ground response & validity button. This page reports what the simulation did to the ground, and whether its result was obtained where the model has meaning. It reads in three blocks, from the response to its limits.

Ground evolution. First what was put into the ground: the mean annual energy exchanged with it (MWh/y), and its long-term thermal balance — cooling energy minus heating energy, MWh/y. Then what the ground did about it: the maximum and minimum EFT reached over the full simulation horizon (°C), the long-term EFT drift (ΔT, °C/y), and the temperature at the centre of the field — its perturbation ΔT(0,0) and its absolute value T(0,0), in °C. The order is the causal one. A non-zero balance means the field is loaded unevenly over the year, and the drift below it is what that imbalance costs: a notable drift signals a field whose performance will move over its design life.

The two extremes are taken over every hour of the horizon, whatever mode the system was in at the time: the maximum is the highest entering fluid temperature the design ever reaches, the minimum the lowest, and neither is restricted to the cooling or the heating hours. A project that only heats therefore still reports a real maximum — the warmest the loop got — rather than the undisturbed ground temperature it started from. Both read — until a computation has produced a fluid temperature to measure.

Temperature limits. The number of hours per year during which the EFT crossed the heat pump temperature limits set on the Heat pump performance panel. A design that respects its limits reports zero here; a handful of hours a year is usually a peak to be accepted knowingly, and a few hundred is a sizing decision to revisit.

Validity envelope. Two figures that describe the domain, not the result. The peak ground load carried by the boreholes (W/m, cooling and heating), which a correctly sized field keeps within roughly 30 to 70 W/m; and the number of hours per year during which the EFT left the range over which the borehole resistance and the heat pump correlations are defined. That second figure matters more than it looks: outside that range the resistance, COP and capacity are held at the end of their curve, so the simulation still converges — on frozen coefficients. Any value other than zero means part of the horizon was computed at the edge of the model rather than inside it.

Computation time and convergence - The footer shared by every page reports the wall-clock time of each stage: the effective borehole resistance (R_b^*), the GHE transfer function (g-function), the entering fluid temperature (EFT) and the time required to display the results. Most of the time, the display of the graphs is the most time-consuming operation.

A stage that did not run reads —, not zero. Not every change asks for every stage: editing a building load recomputes the fluid temperature but neither the borehole resistance nor the transfer function, since neither depends on it. Those two then report no measurement at all rather than 0 ms, which would read as computed instantly. Total is the sum of the stages that did run — the time this refresh actually took.

To ensure the integration of the COP(EFT), CAP(EFT) and R_b^*(EFT) curves, GHE Analysis uses a robust iterative process to reduce the numerical error associated with the ground loads (ɛ_Q) and EFT (ɛ_T). The elements influencing convergence are a COP(EFT) and CAP(EFT) curve with abrupt changes in slope, a high R_b^*, and a circulation flow located in the transitional zone.

If the residuals (ɛ_Q, ɛ_T) fail to settle, the usual remedies are to smooth a heat-pump performance curve that changes slope too abruptly, to add boreholes or length where the fluid temperature swings are extreme, or to keep the circulation flow clear of the laminar-to-turbulent transition. A converged solution shown in green is the signal that the reported energy, efficiency and peak figures can be trusted.

Dashboard donut diagram - To allow an interactive design of the system, most of the numerical values displayed on the console are graphically illustrated on the donut diagram located in the dashboard. By clicking on a piece of the diagram, it is possible to highlight a particular indicator. Progressing from the outside to the inside of the diagram, the rings contain respectively the demand coverage, energy coverage, power demand and energy consumption. Starting from noon and moving counter-clockwise, the first three pieces of each ring correspond to cooling and the last three correspond to heating.

GHE in practice: reporting what the console shows

A design report is most useful to whoever reviews it when it states the conditions alongside the result. Beside the borehole length retained, record the peak and annual coverage of both modes, the seasonal COP, the extreme EFT reached over the horizon and the long-term drift, and the share of the electricity that goes to the circulation pumps rather than to the compressors. Those five figures are on the pages above, and together they let a reviewer decide whether the design is defensible without reopening the model.

Read the convergence before reading the numbers. Every figure on these pages is the output of the iterative loop described above. A solve that has not settled can still fill the pages with plausible-looking values, so the convergence indicator is what says whether they mean anything. Treat a non-converged solve as a result to fix, not as a result to report.

A drift is a design decision, not a warning to dismiss. A long-term EFT drift on page 4 says the field is thermally imbalanced and that its performance will move over the design life. Where it appears, state the drift in the report with the horizon it was computed over, and say what was done about it: a change on the building side, added length, or a deliberate acceptance of the drift.