ISHS Acta Horticulturae 148: III International Symposium on Energy in Protected Cultivation
SIMULATION OF GREENHOUSE FLOOR HEATING WITH A COGENERATION UNIT |
| Authors: | D. Mears, M. Giniger, T. Manning, B. Ekholt |
| Abstract:
Computer simulation is being used to model greenhouse heating utilizing a cogeneration unit providing energy through a floor heating system. Simulation was used as a design tool for the development of a 1.1 hectare commercial greenhouse installation using reject heat from a utility (Manning and Mears, 1981). Simulation is an important tool for examining the concept of cogeneration as there are many design variables. These include: The insulation system for the greenhouse, the heat delivery system, the size of the cogeneration unit relative to the greenhouse and the management strategy for the cogenerator and the back-up system. Economical use of a cogenerator will be determined in part by the capital cost of the unit and the relationship between fuel cost and the value of the heat and electricity produced. The value of the electricity depends upon the avoided retail costs and the purchase price of surplus power sold to the grid. The rates for both of these vary with the time of day including peak, off peak and intermediate rates. This study focuses on the development of models to this question in depth, including options for various control strategies for the system. The major accomplishment to date is the development of the control strategy model and its calibration to real data from an actual research greenhouse heated by a cogeneration unit (Giniger et al, 1983). Also, a simulation model similar to the one developed by Manning and Mears (1981) has been used to examine the contribution to the heating load that could be made with a cogeneration unit coupled to floor heating systems of several types operating under several simple control strategies. | |
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