Hay drying is more relevant than ever – because organic farming and the production of regional dairy products nowadays require a high-quality production chain for green forage, from the plant to the fodder hay. Particular attention must be paid to preserving energy and nutrients in order to optimize milk yield. The latest findings from livestock feed research show that with ventilated hay, concentrated feed can be largely avoided—yielding the same milk performance but resulting in a longer life expectancy and lower vet costs compared to silage feeding.
Moisture removal should be as low-loss and gentle as possible so that the valuable ingredients of the dried hay are preserved.
Grassland forage does not dry evenly. Stalks and stems dry slower, whereas the nutrient-rich ears, herbs, and leaves dry faster. The more often it is turned and the longer this hay remains on the meadow, the more of the valuable portion crumbles away and is irretrievably lost.
With solar hay drying, on the other hand, the wilted forage can be brought in after just 1–2 days. Further drying takes place using the various solar-heated ventilation drying options from CONA. This type of hay drying is economical, ecological, efficient, and, above all, very gentle on the hay and its feed quality.
The highly efficient (772 Watts/m²) CONA solar air collectors with tempered glass covers and efficient absorbers are ISO-certified and therefore eligible for subsidies. Especially in changeable weather conditions, they far outperform conventional roof extraction systems (regardless of design). This near all-weather capability of the CONA solar air collector is precisely what allows farmers to rely on a good final result. Because even when roof extraction systems have long ceased to supply energy, CONA solar air technology still delivers excellent drying results. The investment is definitely worth it here.
While the company’s own CONA control system “CONA-Touch” optimizes daytime operation, secures the hay using interval ventilation during night operation, and ideally prepares it for drying the next day, a combination with a CONA stone storage unit can ensure that drying continues through the night.
Another advantage of hay drying with solar and stone storage is that a hay harvest can also take place toward the end of a period of fine weather, after the sun has charged the stone storage unit during the wilting phase. If the hay needs to be brought in because the weather changes, the hay is simply dried further at home using the stored solar energy from the stone storage. A comprehensive, highly ecological, and at the same time economical way of drying hay without using disproportionately more energy (e.g., dehumidification).
CONA solar air systems can be combined very well with most professional hay ventilation systems; existing drying setups can also be expanded to include solar and stone storage. CONA project planners take existing infrastructure into account and do not exclude any sensible existing system.
The CCS+ solar air collector from CONA has also been Solar Keymark tested and certified according to DIN EN ISO 9806 since 2015.
This results in very good subsidy rates of over 50% for the entire drying system. Just ask us, we will be happy to advise you.
Questions about the eligibility of our CONA systems for subsidies
For detailed information on local funding opportunities for the CONA solar air collector or the solar drying system, your local advisor (e.g., your local bank) is the first point of contact.
Our service for you: We are happy to support you! Through our network, we can put you in touch with the relevant funding agencies. Just talk to us – we are here to help!
Advantages of drying hay with solar drying plants from CONA
CONA® does not leave the use of the sun to chance!
In times of low milk prices and high electricity prices, it is particularly important to produce high-quality, cost-efficient, and energy-saving fodder hay in order to minimize the farmer’s production costs. CONA®, headquartered in Upper Austria, has therefore set itself the goal of revolutionizing hay drying from the ground up. In doing so, it departs from conservative-conventional hay technology; while it adopts proven ideas, it breaks new, more efficient, and above all, more sustainable paths to use only a fraction of the energy to achieve the aforementioned hay quality. When it comes to electricity consumption, not only sustainable but also economic aspects are taken into consideration!
When using the highly efficient (772 Watts/m²), ISO-certified, and therefore subsidy-eligible CONA solar air collectors© with tempered glass covers and efficient absorbers, they far outperform conventional roof extraction systems (regardless of design), especially in changeable weather conditions. This near all-weather capability of the CONA solar air collector© is precisely what allows the farmer to rely on a good final result.
The wilted forage can be brought in after just 1–2 days without crumbling losses, and further drying can take place either in the hayloft using a conventional hay fan, or even more efficiently in a CONA drying box© or with a CONA round bale drying system® using solar-heated ventilation. This is where the intelligent CONA control system “CONA-Touch®” comes into play, which optimally utilizes daytime operation in particular, but also secures the harvest during night operation and prepares the hay for the continuation of the drying process the next day.
Energy savings of an average of 48% and 85% respectively are possible with these system variants:
One variant is to replace energy-intensive drying methods, such as dehumidifier technology, or not even put them into operation in the first place. For the drying itself, conventional hay fans (radial blowers) are combined with solar process heat, saving an average of 48% in electricity.
However, the even more efficient variant is to also replace the hay fan with a CONA hay drying system that is thoroughly thought out from A to Z, featuring intelligent air routing. Through energy-efficient measures in the form of optimized air routing in insulated air ducts, without bottlenecks and with clean thermal breaks, significantly more energy-saving ventilation can be utilized. This protects the maximum farm connection capacity, the electricity bill, and leaves an ecological footprint of modern agricultural management.
Combination possibilities:
The capability to combine the drying energy with grain or wood chip drying from CONA® also offers great added value. In addition, alternative medicinal herb and fruit drying options are possible as additional farm income. Existing energy sources, such as waste heat from wood gasifiers, can also be taken into account during individual planning.
Hay drying technology for loose hay - drying in the hayloft:
Cona offers 2 variants for drying loose hay:
- Integration of solar process heat into conventional hay ventilation for hayloft. Hayloft = drying + storage
- CONA drying system consisting of solar process heat and energy-efficient ventilation technology using flat floor instead of hayloft. Hayloft = drying + storage separated
1) Provision of solar process heat by the highly efficient and eligible CONA solar air collector.
The use of the patented and certified CONA solar air collectors is specially optimized for energy-saing and highly efficient drying processes, which are convining even in changeable weather conditions! Innovative futrue technology beats already today conservative conventional hay technology.
Cold ventilation, inefficient roof extraction, warm air production by resource-intensive biomass combustion and additionally high efficiency loss via the heat exchanger or even the use of electricity-intensive dehumidification can be replaced by the innovative CONA system. The sun heats air in the CONA solar air collector free of charge and thus exponentially increases the water absorption capacity of the air. (Info: warm air can absorb more moisture until saturared) After mixing the extremely dry air in the mixing center, dry warm air is blown into the hayloft, the hay box, in a controlled manner using existing ventilation technology (hay radial fan) at less than 40°C.
The CONA solar air collectors provide the process heat here, saving an average of 48% of the energy costs!
2) CONA heat drying system:
The combination of solar process heat from the highly efficient CONA solar air collectors and the CONA neutral drying technology makes the solution particularly economic, ecologic and, above all, good drying results. Specially in this section, the smart technology beats time-honored drying myths.
Whoever has some space next to the hay store can dry the hay in a CONA hay drying box with patented aeration floor (>500 gills/m2) and sophisticated air cushion process (controlled outflow) instead of conventional hay blowers with high pressure build-up (5m hay loft) in an energy-saving, gentle and uniform way (without chimney formation).
With a bulk height of 1.5 – 2.5m per drying batch, energy saving fans are used, which are interconnected in such a way that drying can be carried out highly efficiently with a fraction of the electricity required by conventional ventilation technology.
This combination of CONA solar air collectors and CONA haybox drying saves up to 85% electricity compared to conventional drying systems, making it the most energy-efficient form of active hay drying currently available.
Advantage: The drying can be used for different goods and the hay storage can be built 6 – 8m high.
Hay drying technology for HAY round bales:
CONA offers 2 variants for drying round bales:
- Integration of solar process heat into conventional hay round bale ventilation
- CONA drying system consisting of solar process heat and energy-efficient flat-floor ventilation technology
Provision of dry, warm solar air through the highly efficient CONA solar air collector
The use of patented and certified CONA solar air collectors is specifically optimized for energy-saving and highly efficient drying processes that deliver impressive results even in changeable weather conditions! Innovative future technology is already outperforming conservative-conventional hay technology today.
Cold ventilation, inefficient roof extraction, warm air production through resource-intensive biomass combustion with high efficiency loss via the heat exchanger, or even the use of electricity-intensive dehumidification can be replaced by the innovative CONA system, as the sun heats the air in the CONA solar air collector for free, thereby exponentially increasing the air’s moisture-absorption capacity. (Info: warm air can absorb more moisture up to its saturation point)
After mixing the extremely dry air in the mixing center, dry, warm air below 40°C is blown into the existing round bale drying system in a controlled manner using existing ventilation technology (radial hay fan).
The CONA solar air collectors provide the process heat here, thereby saving an average of 48% of energy costs!
References
Gut Kastensee / Familie Mainzl (Glonn, Germany)
- Specifications: 360 m² solar surface area with 500 kWh storage unit
- Performance/Output: 800 round bales
- Year of construction:
Kutschera – Upper Austria (Bad Kreuzen)
- Specifications: 110 m² solar surface area with a flat floor and a Platin control system incl. storage unit
- Performance/Output: 240 hay bales (85,000 kg)
- Year of construction: 2023
Geisler – Salzburg (Lamprechtshausen)
- Specifications: 176 m² solar surface area with a flat floor and a Platin control system incl. storage unit
- Performance/Output: 28 ha
- Year of construction: 2021
Ueli Steinegger (Switzerland)
- Type of system: Solar hay drying system with integrated mixing center and radial hay fan.
- Specifications:
- Performance/Output:
- Year of construction:
Frequently asked questions about our solar hay drying plants
The drying time depends primarily on 3 factors:
- Ratio of the drying area to the solar surface area and the weather conditions.
- Initial moisture content upon filling: Ideally, the 2-day hay should be tedded (turned) once a day, then swathed (raked into windrows), brought in, and should no longer exceed a moisture level of 30%.
- State of charge of the CONA stone storage or the performance of the heat exchanger based on the capacity of the heating coil for the night or on bad weather days. Only those who can retrieve full storage capacity here will reduce the desired drying time. This makes it comparable to conventional drying systems, i.e., 2–3 days.
The CONA solar field is ideally integrated into a south, south-west, or south-east roof. East-west combinations can also offer the advantage of a more complete utilization of a sunny day during the hay harvesting season. Pure east or west collector fields should be combined with additional heat utilization (such as a heat exchanger or CONA stone storage).
According to hay expert Wirleitner and the University of Natural Resources and Life Sciences (BOKU), as a rough rule of thumb, around 25 to 30 m² of ventilated area should be available per hectare of batch mowing area.
South Orientation: The solar field corresponds to a 2:1 ratio of the hay box area to be dried at the same time. If the orientation has strong east and west components, it is recommended to dimension the solar field about 15–20% larger (e.g., a total collector area of 240 m² for a 100 m² hay storage box).
General hay knowledge and physical laws apply here as well, which even dehumidification technology cannot disprove. Quote from Wirleitner: “One of the worst mistakes in hay aeration is applying too thick a layer of wilted hay. Excessive layer heights cause the hay stack to collapse quickly, leading to compaction that prevents uniform aeration. For high-capacity systems with warm-air aeration or air dehumidification, a layer height of up to 2.5 m may be acceptable.”
Furthermore, the layer height depends on the maturity of the hay. For six to eight week-old hay with a higher proportion of stems and structural material, the aforementioned layer height is recommended. In contrast, for young hay of about four to five weeks, it is recommended to layer it only 1.5 to 2 meters high due to potential compaction. The first cut should take place around May 20th to ensure a certain level of maturity is already present. The more loosely the hay is handled by the machinery during the harvesting phase (tedder, swather, conditioner, etc.) and the drying phase (hay crane), the easier it is to aerate—meaning compaction can be prevented right from the start.
CONA offers two different drying solution concepts:
a) With the dry, warm solar air from the CONA solar field, drying takes place directly in the hay stack using a conventional hay blower.
b) In CONA hay box drying, the box serves to optimize air distribution during the drying process at a lower layer height. Afterward, the gently dried hay is transferred into storage, for example using a hay crane.
Major advantages:
- Up to 85% lower electricity consumption compared to conventional hay drying methods.
- The layer height of the hay in storage is only limited by the height of the building.
- Versatility: Wood chips and grain can also be dried during the hay off-season.
The main energy is supplied by the solar air collector and not the power grid. In the variant with CONA hay box drying, the fans require approx. 2–4 kW (approx. 0.75 kW for the solar fan and 1.5–3 kW for drying hay bales or loose hay).
This very low power consumption is only possible due to highly intelligent airflow routing, optimized material composition, and insulation of the drying elements.
In the classic variant combined with a hay stack, the power consumption of the hay blower must be added to the solar fan (approx. 0.75 kW). The power consumption of additional components (e.g., dehumidifiers) can then be eliminated.
Further information from our numerous satisfied customers can be found in our references.
Following a joint planning phase, and depending on how the collector field substructure is prepared, a very rapid installation taking just a few days can be carried out, depending on the size of the system.
In principle, a lot can be done on your own. If a stone storage unit is planned, it can be assembled on-site based on construction plans and instructions, just like the CONA ventilation floors. These are only made available to existing CONA Solar customers. Only the intelligent control system, damper technology, and ventilation technology are provided by CONA in this case.
The installation of the collectors is supervised by our installation manager. It is also crucial to ensure a professional installation of the collectors regarding the airflow routing and their connection to the control system to guarantee the high level of efficiency.
The entire system can be used for both solar drying and drying with other energy sources. A combination of a heat exchanger, any existing roof extraction system (available almost exclusively in the summer months), or waste heat from other processes is possible—with us, you don’t waste any energy!
Numerous tests have shown that investing in a CONA air collector pays off:
- 3.5x higher performance compared to a roof extraction system.
- Up to 50% eligible for subsidies.
- No zero-yield scenarios like a roof extraction system, even in changeable weather or windy conditions.
- No auxiliary heating necessary – because the collector is powerful enough (the CONA stone storage is optional and not a must).
- Proper airflow dimensioning, leading to optimal system operation and low electricity costs with a significantly higher efficiency than any roof extraction system.