pierrox.net

What is PierroX.net?

PierroX.net is a personal software-engineering blog where the author writes about technical projects, with a strong recent focus on home solar power (photovoltaics). The site's own tagline is "Software engineering, and more," and the visible content mixes programming topics with detailed write-ups of a self-built solar optimisation system.

A good example is the photovoltaic series, which runs through measuring produced and consumed energy, digital control of a power inverter, a regulation system, dimensioning, and a concluding post that shares real figures and graphs from the author's own house (a household of two adults and two children, including hot-water heating). That makes it a first-hand experience log rather than a general news or tutorial site.

Who it suits

• Engineers and makers who want a worked example of instrumenting and controlling an energy system
• Readers comfortable with French, since the article titles and excerpts are in French
• People deciding whether a solar self-consumption project is worth the effort, who want numbers rather than marketing claims

What to expect

• Project narratives with measurements, graphs and design decisions
• Occasional software-engineering posts beyond the solar series
• No obvious product or service offering; treat it as one practitioner's notes

If you are planning something similar, start with the measurement posts before the dimensioning and regulation ones — you cannot control what you have not measured. For broader context on the technology itself, compare with Home Assistant for monitoring and automation, or Arduino if you want a starting point for the control hardware side.

How does the photovoltaic optimization system work?

PierroX.net documents a personal, engineering-led photovoltaic project, so the clearest answer is that the system works as a feedback loop: measure, compare, regulate and adjust. The site’s series walks through measuring generated and consumed energy, digitally controlling a power inverter, and sizing the setup before drawing conclusions. In practice, the author’s approach is not just “install panels and hope”; it is an instrumentation and control problem.

What the loop does

1. Measure production and consumption — the system tracks how much energy the panels generate and how much the house uses.
2. Compare the two — the gap between generation and use tells the controller what to do.
3. Regulate a power inverter — instead of exporting or wasting excess energy, the control system adjusts how the inverter operates.
4. Size the system — the author covers dimensioning, meaning the hardware and control choices are matched to the household’s real load.
5. Report results — the conclusion uses figures and graphs from the author’s own house, with two adults and two children, including domestic hot water heating.

That last point is the useful part: the author is reporting his own household’s experience, not a vendor’s claim. My practical analysis is that this kind of setup suits someone who wants to use more self-generated solar energy on site and is comfortable with sensors, digital control and a bit of programming or configuration. It is less suited to someone who wants a plug-and-play installation with no monitoring.

A concrete reader scenario

If you have rooftop solar and notice that much of your production is exported at a low tariff while you still buy power in the evening, a control loop like this is aimed at that mismatch. You would start by measuring both flows, then use the inverter control to shift or modulate production rather than treating the inverter as a fixed device.

For broader context on home solar and monitoring, official sources such as U.S. Department of Energy and International Energy Agency explain general principles; the PierroX.net series is most useful for the detailed engineering diary and the author’s measured results.

How do I measure energy produced and consumed in a solar setup?

Measure both sides of the system separately, then compare them over the same time window: production at the inverter or a dedicated production meter, consumption at the main service entry or a subpanel meter. That pairing is what turns raw numbers into useful decisions, such as whether to shift loads or add storage.

What to measure

• Production (DC or AC side): many inverters log daily and lifetime yield themselves; a separate AC meter near the inverter gives an independent check.
• Consumption: a whole-home meter captures everything, while circuit-level meters show which appliances actually drive the peaks.
• Both at once: the interesting figure is usually the gap between production and consumption in the same interval, plus how much is exported or imported.

Practical setup

1. Pick a logging interval — one minute for diagnostics, five to fifteen minutes for long-term trends.
2. Timestamp everything to the same clock, or the comparison will drift.
3. Log for at least a week covering both sunny and cloudy days before drawing conclusions.
4. Store raw data; daily totals hide the midday peaks that matter for sizing storage.

PierroX.net documents a home photovoltaic optimisation project in a series of posts, including one specifically on measuring produced and consumed energy, plus follow-ups on digital control of the power converter and system sizing. It is written as a personal return on experience with real household figures and graphs, so it is most useful if you want to see how one engineer instrumented an actual installation rather than a vendor's overview.

For a broader grounding in metering options and monitoring platforms, Home Assistant is a common way to collect and chart sensor data locally, and OpenEnergyMonitor publishes open hardware and guidance aimed at exactly this kind of energy monitoring.

Choosing your approach

Start with one week of whole-home consumption and inverter production at the same interval; if the self-consumption ratio disappoints you, add circuit-level metering to find out why.

What size photovoltaic system do I need for my home?

There is no single formula that answers this without your own consumption data. The most reliable approach is to work backwards from how much electricity you actually use, then size the panels and inverter around that.

The page evidence from PierroX.net is a useful illustration of that method. Its photovoltaic optimisation series documents a real household — two adults and two children, covering usual needs plus domestic hot water heating — and it treats measurement as a prerequisite: one article is dedicated to measuring both energy produced and energy consumed before any conclusions about regulation or dimensioning are drawn. That ordering matters. Sizing decisions come after you know your consumption curve.

What to gather first

• A year of electricity bills, or better, interval data from your meter if your utility provides it.
• Your daytime baseload, since that is what a system without storage can serve directly.
• Any large loads you could shift — hot water, EV charging, laundry — because shifting them changes the optimal size more than adding panels does.
• Your roof's usable area, orientation, tilt and shading through the day.

A practical decision path

1. Estimate annual consumption in kWh.
2. Estimate what fraction of that you can realistically self-consume, given your daytime load profile.
3. Size the array to cover that self-consumed fraction first; export-only capacity is usually worth less to you financially.
4. Check the inverter's AC rating against the array's DC rating — undersizing the inverter slightly is common and can improve output in low light.
5. Add storage only after you know your evening and night consumption, not before.

Trade-offs to weigh

For a worked example of the measurement-and-regulation side, the series on PierroX.net walks through digital control of a power inverter and the sizing step, which is closer to what an informed homeowner would want than a generic calculator.

Next step: pull your last twelve months of consumption and note the hourly shape for a typical weekday and weekend day. Those two curves, not your annual total alone, are what determine the right size.

What are the results of the photovoltaic optimization experiments?

The results are reported as a personal, measured outcome rather than a formal study: the author of PierroX.net presents figures and graphs from his own home — a household of two adults and two children — covering usual electricity needs plus domestic hot water heating, as part of a seven-part photovoltaic optimisation series.

What the evidence shows

• The final article, "Optimisation photovoltaïque #7 : Conclusion, et pour aller plus loin," is explicitly a retour d'expérience (experience report) built on raw numbers and charts from his house.
• The series documents the full chain: measuring produced and consumed energy (#4), digital control of the power inverter (#3), the regulation system (#5), and sizing (#6).
• The conclusion is framed as a starting point for further work rather than a single headline percentage.

How to read it

Because the results are tied to one household's consumption profile, hot-water demand and system sizing, treat the numbers as a worked example of methodology, not a benchmark you can copy directly. The useful part is the measurement and control approach: instrument production and consumption separately, then tune the inverter and regulation to shift self-consumption.

Next step

Start with article #4 to see how production and consumption were measured, then read #7 for the outcome; if you want to estimate your own case, compare your hot-water heating load and daytime base load against his before assuming similar gains. For broader context on self-consumption sizing, IEA publishes general guidance.

How can I implement digital control for a power inverter?

For a practical starting point, treat digital control of a power inverter as a measurement-and-feedback problem before it is a coding problem. You need to sense what the inverter produces, sense what the load consumes, and adjust a control variable — typically a PWM duty cycle, a reference, or a gain — so the two stay aligned. PierroX.net documents a home photovoltaic optimisation project in a series of posts, including one specifically on digital control of the power inverter's variator and one on measuring produced versus consumed energy. That structure is a useful model: sense, control, size, verify.

A workable build order

1. Define the control objective. For a grid-tied or off-grid inverter, the usual goal is to hold output voltage or current near a reference, or to push the operating point toward maximum power. Decide which quantity is the controlled variable before choosing hardware.
2. Instrument both sides. Measure DC input and AC output with isolated sensors. The PierroX series devotes a separate article to measuring produced and consumed energy, which reflects a real lesson: without trustworthy measurement you cannot tune a controller or prove it works.
3. Close the loop digitally. A microcontroller samples the sensed values, computes an error against the reference, and updates the PWM or variator command. Simple proportional-integral control is usually enough for voltage or current regulation; maximum-power-point tracking needs its own perturb-and-observe or incremental-conductance logic.
4. Size the power stage to match. The series includes a dimensioning article, and that ordering matters — control bandwidth, switching frequency and thermal limits all constrain what the digital loop can achieve.
5. Log and review. Graphs of production and consumption over days are how you catch oscillation, drift and sensor scaling errors that a bench test hides.

Trade-offs to expect

The PierroX write-ups are a first-person account of one household system (two adults, two children, domestic hot water included), so treat the specific numbers as that author's observations rather than universal targets. Your own load profile will differ.

Next step: sketch your sense–control–actuate chain on paper, list every signal you can measure today, and identify which one you cannot — that gap usually determines your first hardware purchase. For broader reference material on inverter topologies and control theory, Texas Instruments and MathWorks publish application notes and simulation examples that pair well with a build log like this one.