The Energy Producing Greenhouse

The EPG is a multi-functional synergetic solar greenhouse system for the production of first-class organic food and renewable energy, which does not depend on the burning of unsustainable resources.

Concept

The use of conventional greenhouses is problematic in sun-rich countries, as it becomes far too hot for the plants inside. The EPG takes this ’waste’ heat out of the greenhouse, where it can be used to generate electrical or mechanical power, or for cooking. The south-facing side of the EPG is shielded by an optical system which extracts up to 80 % of the heat of the sun. Incoming solar radiation is focused onto a black tube containing circulating vegetable oil, which is thereby heated to up to 200 degrees Celsius. The hot oil is stored in a tank of several thousand liters capacity outside the greenhouse, from where it can flow either to a specially developed cooking installation, or to the Sterling engine. The heat removed from the greenhouse can thus be used night or day to bake, fry or boil food, or transformed to mechanical power or electricity. The vegetable oil serves only as a heat transfer and storage medium circulating in a closed cycle. It is not consumed, and lasts for several years.

The diffuse solar radiation that is permitted to pass into the greenhouse has the correct intensity for optimal plant growth. The outer shell of the EPG is a UV-transmitting film with a life expectancy of over 30 years. This allows UV solar radiation, with its natural disinfectant effect, to reach the plants so that no pesticides or fungicides need to be used. Natural UV radiation is also very important for the development of full taste, aroma and color of fruit and vegetables.
Applications

The EPG is a multi-functional system which integrates solar energy collection with the creation of an ideal plant-growth environment and a weather-protective outer shell that allows lightweight interior construction (house-in-house concept).
Applications and synergies include:

• Round the clock solar thermal energy supply for the Sterling Engine, using oil as heat transfer and storage medium.
• Round the clock solar thermal energy supply for cooking – baking, boiling or frying, using oil as heat transfer and storage medium.
• Production of high-quality food free from pesticides and fungicides.
• Space-efficient agriculture.
• Ideal nursery environment for young plants.
• Water-efficient agriculture. A solar chimney with condenser on top of the greenhouse supports air circulation. The reclaimed water from the condenser is reused and the water requirements thereby greatly reduced.

Technical Details

• South-facing side equipped with bi-directionally tracking SunRay optics with 60 times concentration.
• ETFE film cover with high UV-transmission.
• Estimated lifetime: 20 years