Home Posts Tagged "energy-saving" (Page 2)


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Van Uffelen Flowers held an open-doors day to show off its newly delivered four-hectare chrysanthemum greenhouse at Herenwerf in Maasland on Saturday 16 April, together with its builders and installers.

The newly designed Greenhouse was built by Technokas. The greenhouse cover was executed in diffuse glass, with a haze factor of 70. Another interesting detail is the double screening system by Svensson (Harmony 2515) and Bonar (energy-saving blackout cloth), executed by Huisman Scherming. The lighting system was provided by Hortilux Schréder (1,000 Watt SON-T narrow-angle lighting fixtures, 10,000 lux), and the other water and electrical systems were by Stolze.

Next Generation Cultivation

The greenhouse is prepared for the installation of air handling units for mixing the air in the greenhouse with air blown in from outside, in accordance with the basic principles of Next Generation Cultivation. ‘This system allows the entire air content of a greenhouse to be complete renewed approximately once every hour,’ explains Hans van Tilborgh of Technokas. ‘It will not be replacing the air vents, but will comprise a useful addition to them.’ Before the outside air is blown into the greenhouse through a large hose, it is heated to the greenhouse temperature. This is to prevent climate differences in the greenhouse.

However, the system does not provide in heat recovery, like tomato grower Ted Duijvesteijn’s ID Greenhouse. ‘That would mean installing a much more complex system. It also saves energy. In combination with a double screen this greenhouse will allow us to save 30 to 40 per cent more energy than in a conventional chrysanthemum greenhouse,’ continues Van Tilborgh.

Production halls

In addition to the greenhouse, Technokas also supplied Van Uffelen Flowers with hoistable heating frames and production halls, designed by the Poortinga & Zwinkels architecture firm. According to architect Hester Poortinga, Van Uffelen aims to have its new building reflect the brand identity and values of Zentoo: transparent, unifying and innovative. Zentoo is the trademark under which Van Uffelen chrysanthemums are marketed. The chrysanthemum varieties are supplied by Fides and Deliflor.

Other technical tours de force at Van Uffelen Flowers are the Robur fully automated spray boom, the ISO Group peat block planting machine and the Bercomex harvester. Once harvested, the flowers are transported to the shed on underground conveyor belts. The cooling facilities with pre-cooling units were supplied by Hamelink Koeling BV.

Text/photos: Mario Bentvelsen.

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'We should not depreciate the closed greenhouse', 'Greenhouse growers should rely less on feelings and more on knowledge' and 'In the greenhouse sector of 2050 gas is no longer relevant'. These were some of the remarkable statements that were made at the well-attended EnergiekEvent 2016 in Bleiswijk, where the 10th anniversary of Kas als Energiebron was also celebrated.

Looking back, Kas als Energiebron (Greenhouse as a Source of Energy), the innovation and action programme for energy efficiency and sustainability in the greenhouse horticulture sector, was found to be successful. The energy efficiency of the Dutch greenhouse growers has increased significantly, while the energy sources are becoming more sustainable. Especially thanks to geothermal and residual heat, wind energy, (semi-)closed greenhouses, diffuse glass, LED lighting and - the manual is in need of a reprint - Next Generation Cultivation.


The best news of the EnergiekEvent was that the increased energy efficiency does not affect the quality or production. But it does require more data, knowledge and insight of the growers. "Before, there used to be one measuring unit on each hectare. In the future we want to change this to smaller units. Maybe even to micro-controllers for every plant, not only for the production, but also for the quality. For example, think of LED lighting to enhance certain plant components," says Sjaak Bakker, manager of Wageningen UR Greenhouse Horticulture.

Bakker outlined a future in which electricity will play a leading role. "We are rapidly moving towards an all-electric situation. Just look at electric cars, batteries and what's happening in LED lighting. They are already thinking about lighting through foils or glass cells."

Our CO2 supply should also be different in 2030 or 2050, Bakker said. "If we no longer burn gas in the future, where would we get our CO2 from? An example might be extracting CO2 from the air."

Closed greenhouses

Next Generation Cultivation is being succesfully applied in various crops, including tomato and gerbera. An estimated 15 to 20% of the Dutch growers is using this method. A lot of knowledge has been gained in closed greenhouses and during previous research, Bakker said. "In Next Generation Cultivation many things that were already developed have been put together: think of temperature integration, research on screens, air movement, etc."

The closed greenhouse is disappearing, it seems. But Wilco Wisse, chairman of Kas als Energiebron and staffmember of Lans Tomaten, thinks that closed greenhouses should not be depreciated. "We ourselves also have an Optima greenhouse of 1.5 hectares and we know better than anyone how difficult it is to make profits with it. It is actually a huge solar collector though, it stores excess heat of the summer and supplies it in the winter. Therefore, we should not depreciate the closed greenhouse.”

Sustainable future

Leo Oprel, currently working as a policy advisor at the Ministry of Economic Affairs - who is considered as the founder of Next Generation Cultivation at Wageningen UR - outlined a sustainable vision of Dutch horticulture, in which:

  • new greenhouses will look very similar to existing greenhouses
  • gas has been replaced by sustainable electricity and heat
  • virtually no chemical pesticides are used
  • the use of CO2 for growth is limited
  • knowledge is crucial
  • climate control will include energy and ventilation management
  • heat exchangers will become commonplace to transfer energy from the moist greenhouse air to the incoming drier air
  • cultivation is done with more humidity, with a very homogenuous greenhouse climate
  • light is the key for temperature control
  • the diffuse greenhouse roof transmits more light and there are more screens hanging above each other
  • super translucent greenhouses will determine the production - and the existence - in the winter
  • light will be flexibly captured above a certain level in the summer and will be available for energy storage
  • excess radiation is immediately absorbed without the greenhouse air heating up too much
  • assimilation lighting is used on the basis of the requirements of the plant
  • the artificial light is also dimmable because it works with direct current
  • the heat requirement is reduced to 10 cubic meters of gas per m2
  • geothermal energy and heat pumps with heat/cold storage supply the residual heat
  • the backup will consist of batteries
  • offices and industrial buildings supply additional electricity with roof-integrated solar panels
  • windmills are a regular appearance in horticultural areas
  • proud entrepreneurs have created a sustainable future!

Kas als Energiebron, the innovation and action plan for energy efficiency and sustainability in greenhouse horticulture of LTO Glaskracht Nederland and the Ministry of Economic Affairs, will continue until the end of next year. Both the greenhouse horticulture industry and the government want to continue with the program. The ministry of Economic Affairs wants to maintain the 50/50 cost sharing – but is still negotiating with LTO.

At the end, the participants visited the workshops and greenhouses at Wageningen UR/Delphy Improvement Centre, where they were informed of the latest research.

Text/photos: Mario Bentvelsen.

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Leo de Jong is the winner of the Arie van den Berg Innovation award. In the context of the 50th anniversary of Berg Hortimotive, this award is given to a person or company that has a progressive idea for the logistics process in the greenhouse sector.

Inspired by the technology of today's hybrid cars Leo de Jong came up with the idea of generating energy with a pipe-rail trolley! When lowering the hydraulic scissors energy is released, which can be converted into electrical energy by using a simple technique.

Less strain

The energy generated can then be used to recharge the batteries in the pipe-rail trolley. In addition, this system makes sure that the lowering of the scissors puts less strain on the construction and those working on the platform.

According to Arie van den Berg, chairman of the jury and name-giver of the Innovation Award, the idea of Leo de Jong is a well thought out idea for a recognizable problem.

In the coming months a project team will be established with students and teachers of the Avans Hogeschool in Breda and employees of Berg Hortimotive to develop this idea further and to test its (commercial) viability.

Source/photo: Berg Hortimotive.

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Fruit juice producer Haisheng, a Chinese company with more than 2,000 employees, recently ordered an Ultra Clima greenhouse from Kubo. This fully closed 12-hectare greenhouse represents a value of approximately 14 million euros for Kubo.

This is Kubo’s first large-scale project in China. The greenhouse builder was awarded the order by participating in a public tendering procedure. The Westland-based company will deliver part of the greenhouse complex this year. The client, Haisheng, exports approximately 176 million euro in juice on an annual basis.

A breakthrough

Kubo’s CEO and owner Wouter Kuiper (41) called the order for the tomato greenhouse a breakthrough in het Financieele Dagblad (the Dutch Financial Times), because this is the first time that Kubo’s efforts to be granted an order in China paid off. Haisheng ordered an ‘Ultra-Clima’ greenhouse; a special type of greenhouse developed by Kubo only a few years ago. This fully closed greenhouse uses little energy and requires fewer crop protection agents due to the fact that plants grown in a closed environment are less susceptible to disease.

Turnkey project

Kubo will be delivering the greenhouse in China as a turnkey project. The company will be producing as many components as possible in advance in the Netherlands and subsequently ship all the material to China. Local construction workers in China will be preparing the ground and installing the greenhouse under supervision of a Dutch contractor. Kubo was in the news last month as well, when the company was engaged to realise a prestigious project by an oil company in Oman. The company will be building a solar greenhouse complex in the gulf state that generates steam from solar energy. The greenhouse complex will cover 190 hectares and be delivered in 2018.

Source: Financieele Dagblad. Photo: Kubo.

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Although their revolutionary greenhouse has had a superb first year, the brothers Duijvestijn see room for improvement. Technically there are still gains to be made. And, although the goal to save 50% on energy by using low-grade heat was achieved in the first year, the businessmen take little pleasure from that. The system’s partners watch and learn. Where can they still make improvements?

The ID greenhouse that Duijvestijn Tomatoes of Pijnacker, the Netherlands, started running in December 2013 is performing well. In the first quarter, the crop was mostly grown in the conventional way in order to eliminate any technical teething troubles without taking any major risks. Then in the very light and closed greenhouse, step by step, they switched to the Next Generation Growing. This greenhouse concept, jointly developed by Technokas, Boal and Scheuten Glass, lends itself excellently to this purpose.
Noteworthy features of the new greenhouse are: A double glazed roof with large format glass (2x3m); insulation glass with four anti-reflective coatings and a structured layer to scatter the incoming light; air conditioning using air drawn in from outside; heating with low grade (primary) and high grade heat (secondary); continuous ridge ventilation with the opening on the top side; and a construction without any light-intercepting trellises. Instead it uses relatively heavy columns and angled sidewalls to support the greenhouse. The screens are tucked under the gutters.

Special year

Ted Duijvestijn calls 2014 a peculiar year, because the reference crop of plum tomato Prunus, performed exceptionally well. “As a result we weren’t able to achieve any extra yield in the new greenhouse,” he said. “If all the components had immediately performed as we wanted them to, we certainly could have got more out of it.”
Apart from the later planting date and the conventional start to the crop, a few other factors contributed to the setback. One of these was the CO2-supply in the new greenhouse. “We had a central control for the CO2 in which a two way valve distributed the CO2 between the conventional greenhouse and ID greenhouse,” explains Duijvestijn. “Measurements inside the greenhouse showed that sometimes too little CO2 entered the new greenhouse so that the concentration measured next to the closed windows was sometimes under the level outside. Then you know you are missing your chance regarding kilos. This year the new greenhouse had its own CO2-control system.”

Insect mesh removed

Another disappointment was that on warm days there was a shortfall in the ventilation capacity. That was directly related to the insect mesh in the ridge ventilation, which the growers had chosen to install at the last minute. “The mesh had a big impact on the ventilation capacity,” says the grower. “On very warm days, which were quite often last year, the plants were sometimes exposed to stress.”
Therefore, the mesh was removed during the crop changeover. Duijvestijn says that it is now more difficult to manage the secondary goal, which is emission-free production, but the ridge ventilation can now very quickly and in line with the original calculations achieve the desired level of cooling.
“The vents open from the top side to obtain the maximum chimney effect,” he explains. When the windows are fully open it’s possible to refresh about 150 m3 air per m2. Due to the diffuse glass that doesn’t have to happen very often but it is good to have such a fast and powerful system available. The capacity to draw in outside air is 10 m3/m2 per hour and is used mostly for the fine-tuning.

Double glass

The advanced and expensive double glazed roof largely meets expectations although Duijvestijn would like to see less condensation.
“That certainly has our attention,” says product manager horticulture Laurens Vlaar, of Scheuten Glass. “We are all convinced that double glazing adds value, but we also know that glass is extremely differentiated and complex. Together with the users and research institutions we want to initiate improvements where possible and offer tailor-made solutions. These could include different structural treatments that you can apply in order to achieve the desired scattering of light. Every type of structure has its advantages and disadvantages. With hindsight we can see that the pyramid structure in this greenhouse roof is a little too coarse. A finer structure would probably lead to fewer problems with condensation.”
Peter Zwinkels, of Technokas, adds: “This has also opened my eyes. In the past condensation was often seen as an inevitable side-effect but in recent years it has started to receive the attention it deserves. Nowadays we always test glass samples that are wet and the differences can be amazingly large. Wageningen has a great setup for taking measurements which we thankfully can use.”
One thing that Zwinkels would like to do differently in this context is take measurements when the glass is at an angle, just like when it is on the greenhouse roof. Currently glass samples are only measured when they are horizontal and that, certainly with respect to condensation, can give a distorted picture.


Glass producer Scheuten, as a project partner, is closely involved in several new greenhouse concepts in the Netherlands. Despite the still relatively high cost, Vlaar sees a lot of potential for well-insulated, double glazed greenhouse roofs using diffuse tempered glass with AR-coatings.
“The projects which we have been able to achieve so far are fairly small scale and therefore relatively expensive,” he says. “Before there’s a further roll-out, the project volumes need to increase to enable a serious decrease in price. For projects of several hectares that is feasible, certainly now that we are better able to deal with the particular nature of horticultural projects.”
Wageningen UR Greenhouse Horticulture was not only consulted for determining the glass specifications, it also provides the monitoring program. “That’s very valuable,” says Duijvestijn. “Before we invested in this greenhouse I was intensively involved in all kinds of trials for three years. However, I’ve actually learned the most from using it, not least, thanks to the monitoring by the researcher.”

Invest in research

Together with Zwinkels and Vlaar he stresses that the sector and the government should keep up their joint investment in research. The relative reticence that has occurred over the last few years gives him reason for concern. “There have been many cut backs and in my opinion potential financial partners sometimes say no too easily to subsidy applications for research,” according to Zwinkels. “That is partly due to a lack of strategic focus and expertise."
The greenhouse builder cites Next Generation Growing as an example. “I have already seen several requests fail because they were not thought innovative enough. However, many variations are being designed. Growers must be able to make informed choices and that requires comprehensive research and testing. Growers also want to pay but it makes a difference if other parties continue to make a contribution and thereby reduce the business risk to an acceptable level. That is what happened here. Without external help this greenhouse may never have been built."


The energy target (50% energy savings) was achieved in the first year of production, but by a combination of circumstances no extra yield was achieved in the ID Greenhouse. Now the greenhouse has its own CO2 control system and the insect mesh over the ridge ventilation has been removed, so that may now be possible. The well insulated, double glazed roof made of diffuse glass has excellent transmission properties. The condensation behaviour, in relation to the treatments used to make the glass diffuse, deserves extra attention in future projects.

Text/photos: Jan van Staalduinen

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With a little more effort you can improve even more. This is the approach behind new trials aimed at optimizing water and fertiliser use with the specific aim of reducing fertiliser emission to the environment. It sounds rather demanding until you realise that the quality of the end product can also improve, while maintaining or even increasing yield. Excess drain as an insurance policy for the cultivation is an out-dated idea.

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