ISHS Acta Horticulturae 927: XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Greenhouse 2010 and Soilless Cultivation
DESIGN AND MODELLING OF NOVEL SYSTEM FOR HEATING AND COOLING OF SEMI-CLOSED GREENHOUSES IN MILD WINTER CLIMATE AREAS BASED ON FINE WIRE HEAT EXCHANGERS AND WATER STORAGE ON TANK |
| Authors: | B. Bailey, E.J. Baeza, J.C. López, J.J. Pérez-Parra, J.C. Gázquez, J.I. Montero |
| Keywords: | diffuser, thermal stratification, energy balance |
| DOI: | 10.17660/ActaHortic.2012.927.73 |
| Abstract:
A greenhouse energy and climate model (HortiAlmería) based on the Horticern greenhouse energy model developed by Jolliet et al. (1991) and which includes the treatment of humidity and transpiration used in the Hortitrans model (Jolliet, 1994) was used to design an model a novel system for heating and cooling a semi-closed greenhouse compartment (160 m2) based on fine wire heat exchangers and water storage. Calculations were performed for winter time and two different hypotheses were studied: single energy store without heat pump, heat pump with hot and cold energy stores. Some of the most important aspects analysed were the influence of energy store capacity on heat demand of experimental greenhouse with single energy store, the heat store capacity for different types of heat pumps, the increase in net CO2 assimilated with increasing energy store capacity, increased photosynthesis permitted by partial closure of the greenhouse, the influence of greenhouse light transmission and air tightness on profit from CO2 enrichment, a study of the number of heat exchanger units necessary to achieve the desired conditions. To maintain and enhance thermal stratification in a single thermal store, water has to be added and removed a way that minimises disturbances. This requires two diffusers, one to withdraw cold water from the bottom of the store and the other to introduce warm water at the top. The diffusers should permit a uniform flow across the entire horizontal plan area of the store. A design of such diffusers is presented in the paper. | |
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