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Albert B.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Brajeul E.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Le Quillec S.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Lesourd D.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Loda D.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl
Acta Horticulturae | Year: 2014

The principle of relocating the heating system consists in placing lowerature heat emitters as close as possible to the crop - contrary to the common practice in professional glasshouses in the West of France - in such a way as to warm the plants rather than the air. As for the air dehumidification/cooling management, it could be expected through thermodynamic treatment or ventilation/forced outside air intake. Such experiments were carried out by the Ctifl Center in Carquefou from 2010 till 2012. The aim of these trials was to gain insight into the influence of relocated heating and of various air management modes by establishing an energy and economic balance for each climatic system. As overall results, both air dehumidification/cooling management modes offered a low added value compared to the relocation of the heating networks. The relocated heating system should represent the optimal technical-economic balance in greenhouse cucumber cultivation. Besides, it is in no case incompatible with temperature integration and lowering of the heating temperature set-point during the night in order to rationalize energy consumptions. These findings will continue to help the French greenhouse growers both to minimize heating costs and optimize air management while controlling the risks of disease and maintaining the crop performance.


Albert B.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Le Quillec S.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Brajeul E.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Lesourd D.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Loda D.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl
Acta Horticulturae | Year: 2014

In the perspective to reduce the energy costs in heated glasshouses, the research works at the Ctifl Center in Carquefou focused on the air processing techniques such as the thermodynamic dehumidification as an alternative to the conventional and expensive dehumidification both based on heating and aeration. Following an experiment conducted in 2011 and targeted on fruit yield improvement to secure the technical and economic viability of this new system, the investigation in 2012 was about the specific management of humidity during the early-morning increase of temperature, with a view to limit the sanitary risks linked to Botrytis cinerea and to optimize energy consumption by providing an alternative heating source. The objective of this study was therefore to characterize the impact of the use of thermodynamic dehumidification for that purpose on glasshouse climate, plant development and microclimate, agronomic yield and energy balance. The results demonstrated that: i) there is no risk of condensation on the tomato fruit in the crop treatment with a dehumidifier, that leads to a perfect sanitary control towards Botrytis despite the absence of heating and slightly lower temperatures of air and fruit compared to the control compartment with classic heating network; ii) plant growth and development and cumulated yield on the whole campaign scale are generally similar between both treatments; iii) the energy saving with thermodynamic dehumidification reaches 16% compared to the control. However, when considering the costs for additional electric consumption and liquid CO2 supply, the economic balance of the use of a dehumidifier is negative even before taking the investment cost into account. As a consequence, the thermodynamic dehumidification showed not enough advantages to be kept in the French western conditions of soilless tomato crop in glasshouse.


Aubert C.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Bony P.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Chalot G.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl | Hero V.,Center Technique Interprofessionnel des Fruits et Legumes Ctifl
Food Chemistry | Year: 2010

The effects of storage and post-harvest maturation on the physicochemical characteristics and volatile constituents of Bergeron apricot were investigated during the 2007 season over two experiments. Fruits, harvested at two distinct stages of maturity, in two different experimental orchards, were stored in cold chambers at +1 °C for up to 3 weeks and then subjected to a post-harvest maturation in ripening chambers at 20 °C and 60-70% RH up to 7 days. Firmness, soluble solids (SS), titratable acidity (TA), and the levels of the main volatiles were determined. Physicochemical changes included a significant decrease of firmness during both storage and post-harvest maturation whereas the levels of SS and TA were found to be very similar. The results also indicated that, whatever their initial stage of maturity at harvest, the rates of softening of apricots during storage and/or post-harvest maturation were very comparable. During post-harvest maturation, the levels of C 6-compounds decreased drastically whereas, at the same time, those of esters, lactones and terpenic compounds greatly increased. During storage at 1 °C, a decrease of C 6-compounds was also observed. As regards other compounds, there were some statistically different results between samples but the changes observed for lactones, esters and terpenic compounds were relatively small in comparison to those observed during post-harvest maturation at 20 °C. The results also showed that, at the end, qualitative and quantitative differences can be observed in the "ready-to-eat" apricots according to their initial stage of maturity at harvest. On average, apricots harvested at the most advanced stage of maturity have, on average, the highest levels of soluble solids and the highest levels of volatile compounds of interest. © 2009 Elsevier Ltd. All rights reserved.

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