‘Cultilene made the total picture come together’
A unique greenhouse system – the Daylight Greenhouse – is under construction at Ter Laak Orchids in the Dutch town of Wateringen. This kind of greenhouse creates a win-win situation: both substantial energy savings and the perfect greenhouse climate for shade-loving Phalaenopsis plants. Saint-Gobain Cultilene – a provider of glass since 2012 – supplied Albarino glass for the Daylight Greenhouse and thus became one of the key partners in this unique project.
The Daylight Greenhouse is an innovative greenhouse concept created by Technokas in the Dutch town of De Lier. The concept was developed to save on energy consumption while also making it possible to maximise control over the amount of light in the greenhouse. It was this last advantage in particular, and the fact that only diffused light would enter the greenhouse, that aroused the interest of Eduard and Richard ter Laak. With a production of 6,000,000 Phalaenopsis plants a year, their company, Ter Laak Orchids in Wateringen, is one of the largest orchid-growing companies in the Netherlands. Two years ago, they also added a location in Guatemala. ‘Tests conducted at Wageningen University & Research (WUR) showed that pot plants, including orchids, thrived in this greenhouse,’ said Richard ter Laak. ‘This is because orchids do not like full sun but prefer a spot in the shade. For us, this was the most important reason to get involved in this project and to continue developing the concept with Technokas. The fact that it would also save energy was another nice plus.’
Energy savings and benefits for growth and quality
A characteristic of the Daylight Greenhouse is that it uses double glazing. ‘Installed between these two layers of glass on the south-facing roof are plastic Fresnel lenses,’ explained Hans van Tilborgh from Technokas. ‘These lenses capture all the direct sunlight which is then collected by heat collectors. This means that only diffused light enters the greenhouse. The harvested solar heat is stored and can then be used during the night or during the winter to heat the greenhouse. To get the most out of the double-glazed roof, the greenhouse is being provided with a ‘New Way of Growing’ (HNT – a Dutch cultivation strategy) system that includes active dehumidification using the intake of external air.’
Simply because the Daylight Greenhouse is being equipped with insulating glass and is making use of ‘The New Way of Growing’ concept, it will be able (unlike other modern greenhouses) to save around 30 percent on heat consumption year-round. ‘When you add the sustainable energy harvest, you get a total savings of 60 to 70 percent on heat generated by fossil fuel.’
Ter Laak also sees growth and quality benefits. ‘Because all the light entering the greenhouse is diffused, the result is a more stable greenhouse climate,’ said Richard Ter Laak. ‘Although we still have screens installed, 60 percent of the direct light is removed immediately. This means that most of the sunlight is immediately eliminated even during fluctuating weather conditions. This calms things down in the greenhouse since you always have to deal with a certain response time if you only have retractable screens. With all of these improvements, we can dare to admit more light, and this will ultimately result in growth and quality benefits. We might not have the figures to prove it yet, but the results so far look promising.’
The decision to use Albarino glass
Ter Laak Orchids acquired four years of experience with the Daylight Greenhouse principle in a pilot greenhouse covering 0.4 hectares. At this time, the concept is being expanded: a new 5-hectare greenhouse is under construction. It’s now fully glazed and is expected to be in use by the spring of 2018.
Although various glass suppliers were considered, Cultilene was the final choice. Ter Laak’s Daylight Greenhouse is glazed on its south side with two layers of Albarino Zero Crystal Plus (91+) tempered float glass provided on all four sides with an AR coating. Chosen for the north-facing roof was insulating glass with tempered Albarino High Haze and Albarino Zero Crystal (90+) filled with argon. ‘The most important thing for us was that the glass would have to diffuse as much light as possible since Phalaenopsis plants do not tolerate direct sunlight,’ said Richard ter Laak. This was why we chose Albarino High Haze glass: it has a light dispersion of 80 percent.
Hans van Tilborgh emphasised that Cultilene was selected as a glass supplier primarily because of its ‘total picture’. ‘Cultilene presented us with an offer of both a good price and good technical aspects. Important factors in our decision were the kind of AR coating and how it was applied. But so were the sealing, the technical support and how the project was approached. In short, many aspects were considered before we selected Cultilene. Cultilene made the whole picture come together.’
Van Tilborgh indicated that working with Cultilene was a pleasure. ‘Every project has its setbacks, but Cultilene pursued them very effectively. Cultilene’s flexibility contributed to getting the greenhouse fully glazed two weeks earlier than expected!’