A GREENHOUSE SYSTEM WITH ENERGY STORAGE AND HIGH LEVEL CO2 ATMOSPHERE

J. Løvseth
For a large part of the year, a typical greenhouse at northern latitudes, has to be vented in sunny periods, to release excess heat, whereas heat has to be added to keep the temperature up during the night and in bad weather.

In this paper we discuss a greenhouse system which store solar energy during periods of surplus by circulating the greenhouse air through a rock-bed. During cold periods the circulation is reversed, and energy is transferred back to the house. It is shown that the large surface area of the stones makes the temperature loss in storing and retrieving the heat negligible.

As an example, a greenhouse in the Oslo area (60°N) with double glazing and a suitable rock storage will need little or no extra heating from early April to late September for tomato culture.

The system may also be combined with a seasonal storage from which heat can be recovered with a heat pump during the winter period.

Apart from leakage, the air circulation in the system can be closed. The CO2-content of the greenhouse atmosphere can therefore easily be controlled, also in the most important growing periods with direct sunshine when normal greenhouses have to be vented. This is expected to give a substancially increased productivity.

In section 2 we analyse the variation of the heat balance over the year for greenhouses. We use meteorological data for the Oslo region to give a numerical estimate. The problems connected with heat storage and transfer are discussed in section 3. In the final sections, we discuss CO2-enrichment and give some conclusions.

Løvseth, J. (1981). A GREENHOUSE SYSTEM WITH ENERGY STORAGE AND HIGH LEVEL CO2 ATMOSPHERE. Acta Hortic. 115, 605-616
DOI: 10.17660/ActaHortic.1981.115.68
https://doi.org/10.17660/ActaHortic.1981.115.68

Acta Horticulturae