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Dutch government and greenhouse horticultural practice aim for strongly reduced fossil energy use and of environmental loads in 2010 and energy neutral greenhouses in 2020. This research aims to design a greenhouse concept with minimal use of fossil energy and independent of nearby greenhouses. The concept is called the zero-fossil-energy-greenhouse. This paper presents a theoretical design study and analysis to assess the viability of a zero-fossil-energy-greenhouse concept. The greenhouse was designed for Dutch circumstances and relies on available stateof-art technologies. Nine concepts were generated and evaluated by a panel of experts. Although, none of the concepts was unanimously selected, one of the concepts received on-average highest votes. It uses an aquifer for long term heat and cold storage. Geothermal heat and a heat pump connected to the warm pit of the aquifer are used to heat of the greenhouse. Electricity need is covered by greenelectricity. Cooling and dehumidification of the greenhouse is realised by a heat pump combined with the cold aquifer pit. This concept was more thoroughly evaluated in a simulation study that assessed design consistency and evaluated greenhouse performance in view of design requirements. From the simulations it was concluded that a combination of geothermal heat and a heat pump/aquifer can cover the heat demand of the greenhouse with help of heat buffers, but a fully closed greenhouse concept is not manageable in the summer season. With given technology the chosen concept was not able to cool and dehumidify greenhouse air to target temperature and humidity. A semi closed greenhouse solves this problem.

Protected cultivation systems are used throughout the world as a powerful instrument to produce crops. They protect the crops from unfavorable outdoor climate conditions and pests and offer the opportunity to modify the indoor climate to create an environment that is optimal for crop growth and production, both in terms of quality and quantity. A quick scan of protected cultivation systems presently in use reveals that various types of protected cultivation systems have evolved in time. These cultivation systems differ for instance in terms of construction and cover materials used, the presence and use of different types of climate conditioning equipment, soil or soilless cultivation and nutrition. These differences are determined by the local climate, the availability of water, soil and water quality, the availability of capital, labor and materials and local legislation, to mention a few. With these observations in mind, this paper addresses the question of how to design a protected cultivation system that best satisfies the local conditions in the region considered. This is a multifactorial design and optimization problem. This research aims at developing a generic design tool, using available knowledge for instance contained in heuristic and mathematical models. In this paper, the outlines of a systematic design procedure to design protected cultivation systems are sketched. The design of a minimum fossil energy greenhouse is used as example to illustrate the approach.

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