The Solar Greenhouse: state of the art in energy saving and sustainable energy supply

The objective of the solar greenhouse project was the development of a Dutch greenhouse system for high value crop production without the use of fossil fuels. The project was completed and the results are reported here. The main approach was to first design a greenhouse system requiring much less energy, next to balance the availability of natural energy with the system¿s energy demand, and finally to design control algorithms for dynamic system control. This paper discusses the first two design steps. Increasing the insulation value of the greenhouse cover was the first step towards a reduction in energy demand. The challenge was in maintaining a high light transmission at the same time. A first generation of suitable materials was developed. The realizable energy saving is almost 40 %. The next reduction in fossil fuel requirement was accomplished by capturing solar energy from the greenhouse during the summer months, storing it in an underground aquifer at modest temperatures, and finally using the stored energy during the winter months by using heat pumps. Then the total realizable energy saving is more then 60%. For sustainable energy supply per ha greenhouse at this low energy demand 32 ha biomass is needed, or 600 kW nominal wind power or 1.2 ha PV assuming storage via the public grid

Additives make greenhouse films universally effective

Toevoegingen maken kunstoffilms concurrerend alternatief voor glas in kassen. Ze bevorderen de doorlating van licht, verlengen de levensduur van de film en gaan condensatie tege

Measurement of optical properties of greenhouse cladding materials : harmonisation and standardisation

The aim of this European SMT (Standards, Measurements and Testing) project was the development of testing methods for measuring the ageing and the condensation behaviour of plastic films. For the ageing task, the degradation rates of the most important physical, optical and mechanical properties of the film were measured. Amongst others, harmonisation had to be achieved on measuring the optical properties of plastic films. For this purpose identical samples of four different co-polymer films and also special antifog films were measured by the partners. Measured were the direct and diffusive light transmittance, haze, the UV- transmittance and the IR-transmittance (longwave). Harmonisation has been achieved on the terminology, methods, set-up, repetitions, wavelength bands, etc. of the optical properties of greenhouse plastic films

De Zonnekas : gewasproduktie zonder fossiele energie

The Solar Greenhouse project aimed at the development of a greenhouse system for high value crop production with sustainable energy supply. The project meets the EET goal to substantially increase contribution of sustainable energy in energy supply. Moreover CO2 emission is reduced considerably. The research contained three themes: Decrease of the energy demand of the greenhouse system. Matching the time patterns of sustainable energy supply and greenhouse energy demand and Optimal control of the designed greenhouse syste