Solar Wall Collectors & Heating Containers for Barns and Farms

In poultry, pig, and calf barns, large amounts of outside air are drawn in and heated every day. A perforated solar air collector (transpired solar collector) on the facade captures the low winter sun and preheats that outside air for free before it enters the barn. No heat pump, no buffer tank, no extra electricity demand: the same fan that already ventilates the barn does the work.

83% peak efficiency · 25–40°C temperature rise · 25+ year lifespan · works at -40°C

Why a Wall and Not a Roof?

In winter, the sun hangs low. A vertical facade collector captures that low sun exactly when the barn has its highest heat demand. A roof-mounted system yields less in winter, precisely when the heat demand is greatest. Moreover, the roof remains free for solar panels or other facilities.

How It Works in a Barn

The facade consists of dark-colored, perforated aluminum plates with an air gap of a few centimeters. The sun heats the metal to 60–80°C. The barn ventilation draws the outside air through the 1.6 mm perforations, where the air absorbs the heat from the plate along the way. The pre-heated air goes directly into the barn.

The technology connects directly to a conventional barn ventilation system. No buffer tank, no piping, no frost protection. The collector works when the sun shines; on dark days and at night, the existing heating takes over. It is an addition, not a replacement.

Need More Heat or No Suitable Facade? The 40ft Container Option

If your barn lacks a large south-facing wall, or if you need 24/7 heat (including nighttime), we offer the 40ft Solar Heating Container. It uses the exact same wall collector technology (30m²) but is combined with a 10m³ thermal gravel battery inside the container. This stores excess daytime heat to keep your barn warm all night long—without relying on diesel or gas.

The Plate and the Coating: Where the Heat is Made

The core of the system is a dark, perforated aluminum plate. The quality of that plate — and especially the coating on it — determines how much sunlight is converted into usable heat. That is why we do not use standard plate, but AlMg3 aluminum with a selective high-absorbing solar coating.

Why AlMg3 Aluminum?

AlMg3 is a seawater-resistant aluminum alloy with a high magnesium content. This makes the plate:

• Corrosion-resistant: Resistant to ammonia, moisture, and barn air.
• Strong enough: For a lifespan of 25+ years.
• Light enough: To mount on a facade without heavy construction.
• Highly heat-conductive: The absorbed heat is quickly released to the air.

Why a Selective Coating?

A standard matte black plate absorbs sunlight well but also radiates the absorbed heat back into the environment. A selective coating does something smart: it absorbs a large portion of sunlight but keeps heat radiation low. The result:

• Up to 95% absorption of incoming sunlight.
• Low emission: The plate loses less heat to the outside air.
• Higher plate temperature on cold, clear days.
• More usable heat in the airflow to the barn.

This difference is especially noticeable in winter. On a clear day at -10°C, the plate absorbs more sunlight and loses less heat than a standard matte black plate. The air drawn through the perforations therefore becomes warmer — and that is exactly the air going into your barn.

The Perforations: 1.6 mm, 2% Open Area

The plate is perforated with 1.6 mm holes, in a staggered pattern, with an open area of 2%. This is not a random choice:

• Small holes ensure high air velocity through the perforations.
• High air velocity creates turbulence close to the metal.
• Turbulence removes the insulating heat layer from the plate.
• More heat is transferred to the air.

The result is high heat transfer without needing a heavy fan. The same fan that already ventilates your barn does the work.

What It Delivers for Your Barn

• 83% peak efficiency: The perforated aluminum plate captures up to 83% of incoming solar energy — one of the highest efficiencies in the market for air heating.
• 25–40°C temperature rise: In standard ventilation mode, the collector delivers air that is 25–40°C warmer than outside. In low-flow mode, up to 80°C temperature rise is possible — ideal for rearing barns, piglet nests, and drying processes.
• Up to 30% less fuel consumption: In poultry and pig barns, savings on traditional fuels of up to 30% are reported. In cold, sunny climates, savings are higher — up to 40–50% — due to more winter sun and higher fuel prices. (Actual savings depend on climate, animal type, ventilation rate, insulation, and fuel prices).
• Drier barn climate: Because the incoming ventilation air is heated directly, the relative humidity in the barn drops. This provides drier bedding and fewer moisture problems.
• Less draft and better air quality: The metal facade forms an extra windbreak that prevents cold drafts at the inlet.
• No grid congestion: The facade generates heat, not electricity. The energy is used directly thermally in the barn and does not burden the power grid.
• No glass, no snow problems: The vertical plate has no glass or polycarbonate. Snow slides off or falls through the perforations. Within an hour of sunrise, the plate is snow-free and working again.
• 25+ year lifespan, 10-year warranty: Aluminum does not rust. Rain washes dust through the perforations. The fan is the only moving part — and it is easy to replace.

Why Cold is Actually Good

It sounds contradictory, but the colder the outside air, the more efficiently the collector works. The temperature difference between the hot metal (60–80°C) and the ice-cold outside air is so large that the heat is released to the air very quickly. This is called the counter-flow effect. A clear winter day at -10°C therefore yields more usable heat than a gray day at +5°C.

What a Barn Needs

A barn requires heat all year round, not just in the coldest months. In poultry, barn temperature starts around 32°C during the brooding period and gradually drops to about 22°C as the animals grow. As a result, a poultry barn may need heating for up to ten months a year — including spring and autumn when the sun is already quite strong. Precisely in that period, a facade collector yields a lot.

In practice, the collector is sized on minimum ventilation, not maximum ventilation. A useful design guideline is an airflow of up to approximately 23 m³ per hour per m² of barn floor area.

Investment and Payback Period

The aluminum plate is one of the more expensive components. A perforated plate with a selective coating costs, depending on order size and current aluminum prices, from approximately €65 per m². On top of that come the frame, insulation, fan, ducts, controls, and installation.

Because material prices fluctuate, we work with realistic starting prices (installed) as an indication:

• 10 m² system: from €4,500
• 20 m² system: from €9,000
• 30 m² system: from €13,500
  (Complete prefab units/cabinets or 40ft Containers: price on request)

This amounts to a guideline of €450 to €600 per m² collector, including installation and all components.

Payback period: Strongly dependent on your barn's fuel bill. For a barn with annual heating costs of €15,000 to €25,000 and a saving of 25–30%, a 20m² system pays for itself in 2 to 4 years in the Netherlands, and in 1 to 2 years in cold, sunny climates. After that, the heat is free for 25 years.

Example Calculation:
Suppose a poultry barn with annual heating costs of €18,000 installs a 20m² collector on the south facade for an amount starting at €10,000. At a 30% saving on heating costs, that is €5,400 per year. The payback period is then less than 2 years. After that, the heat is free for 25 years. (Note: this is an example calculation. Your exact payback period will be provided in your quote).

Suitable For Which Barns?

• Poultry barns with brooding periods and continuous heat demand.
• Pig barns, especially piglet rearing and farrowing houses.
• Calf and young livestock barns.
• Barns with mechanical ventilation and a central outside air intake.
• Barns with a free south, east, or west facade.

Where It Is Less Suitable

• Naturally ventilated barns without a heating demand (e.g., many adult dairy or beef barns).
• Barns where the air inlet is next to manure storage or barn air exhaust.
• Barns with a facade that is too small, shaded, or heavily built up.
• Barns where minimum ventilation must remain fully open and there is no heat demand.

Points of Attention During Installation

• Outside air only: Never recirculate barn air through the collector — this causes contamination, ammonia, and moisture in the collector.
• Material choice: Ammonia and dust require coated aluminum or stainless steel. Our standard is AlMg3 with a selective solar coating — resistant to ammonia and moisture.
• Cleaning must be possible: The perforations can become clogged with dust, pollen, and insects. Ensure accessibility and a cleaning schedule.
• Summer bypass: Outside the heating season, the air must be able to bypass the collector so you don't unnecessarily heat the barn.
• Minimum ventilation remains leading: The collector must not reduce barn ventilation. It only lowers the heating demand.
• Fire safety and insurance: Align materials and ducts with your insurer and the municipality.
• Inlet placement: Not near manure storage, not near barn air exhaust, and not in the wind shadow of other buildings.

Technical Specifications

• Material: AlMg3 aluminum (seawater resistant) — available in 0.5 mm, 0.8 mm, and 1.0 mm thickness (depending on the project).
• Dimensions: 1 × 2 m (2 m² per plate) — other sizes on request.
• Coating: Selective high-absorbing solar coating (absorption approx. 95%).
• Perforation: 1.6 mm holes, 2% open area, staggered pattern.
• Efficiency: Up to 83% peak.
• Temperature rise: 25–40°C standard, up to 80°C in low-flow mode.
• Airflow: 50–150 m³/h per panel.
• Lifespan: 25+ years.
• Warranty: 10 years.
• Works at: -40°C and colder.
• Produced in: The Netherlands.
• Shipping: Loose 0.5 mm perforated plates are shipped rolled in a cylinder. Thicker plates (0.8 mm and 1.0 mm) and complete prefab units (cabinets/containers) are delivered flat-packed on a pallet.

Honest About the Limits

The figures on this page come from the practical experience of large barn installations. They are indications, not guarantees. Every barn requires its own sizing based on ventilation rate, animal type, facade orientation, and the existing heating system. On dark days and at night, the collector yields nothing and your existing system takes over.

What you can expect: a noticeable reduction in your heating costs in the shoulder seasons and on sunny winter days, a drier barn climate, and better utilization of a facade that would otherwise remain unused.

Conclusion

The facade is the largest unused surface of your barn. With a perforated solar air collector, you harvest free heat there, directly into your ventilation system, without a heat pump or buffer tank. If you need 24/7 heat or lack a suitable wall, our 40ft Solar Heating Container offers the perfect mobile alternative. The technology has been proven for decades in livestock farming.

83% efficiency. 25–40°C temperature rise. 25+ year lifespan. Works at -40°C. No glass, no snow problems, no maintenance.

Want to know what is possible for your barn? Request barn advice — we look at your ventilation, facade orientation, and heating costs, and calculate it for free.

📧 Email: info@transpiredsolar.com
🌐 Website: transpiredsolar.com
📍 Location: The Netherlands
💬 WhatsApp: +31 6 2044 7198 (text only)

Transpired Solar — Wall collectors and heating containers for farms.