• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    An evaluation of the economic benefits of active cooling and carbon dioxide enrichment of greenhouse cucumbers (Cucumis sativus L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University

    Icon
    View/Open Full Text
    01_front.pdf (2.001Mb)
    02_whole.pdf (18.62Mb)
    Export to EndNote
    Abstract
    Cooling a greenhouse with a refrigeration system rather than conventional ventilation makes it possible to maximise the fractional enrichment time for carbon dioxide, and more importantly enrich during periods of high photosynthetically active radiation. Using conventional climate control methods, enrichment is limited to periods when the greenhouse is not being ventilated, thus reducing the potential enrichment time of the crop. The objective of this study was to develop a simulation model of a greenhouse crop growing with a closed cycle climate control system, using a heat pump, with a reversible (dual) cycle, for heating and cooling. A computer implemented mathematical model developed by Wells (1992) was modified to simulate cucumber crop growth in a greenhouse of commercial size and allowing certain parameters to be set. These parameters included: two types of control system, four levels of enrichment, three crop periods, and at two locations, Auckland and Christchurch. The three crop periods chosen were 26 Jan to 26 April, 25 May to 23 August, and 20 September to 19 December. The two types of control involved conventional fan ventialtion and electric heating, and closed cycle climate control using a reverse cycle heat pump. Greenhouse carbon dioxide enrichment levels used were 350, 600, 900, 1200 μ1.1-1 . The two locations chosen were Auckland and Christchurch. An economic analysis of the results was carried out calculating Annual Marginal Return (AMR) and Internal Rate of Return (IRR) for treatments compared to control. It was concluded that carbon dioxide enrichment combined with conventional control is a worthwhile investment in Christchurch but less so in Auckland. Due to the high capital cost, carbon dioxide enrichment combined with closed cycle climate control is a less attractive investment. However, as considerable energy savings are possible with closed cycle climate control, it is worthwhile investigating other less expensive forms of closed cycle climate control. The economic feasibility of the application of this technology to other, higher value, crops is worthwhile investigating.
    Date
    1996
    Author
    Van Heijst, Marcus Johannes Aart Everardus
    Rights
    The Author
    Publisher
    Massey University
    URI
    http://hdl.handle.net/10179/12727
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1