FEASIBILITY OF A REJECT WATER HEATED GREENHOUSE
An economic analysis was conducted to determine the feasibility of using reject water from a power plant to heat a 2 ha glass greenhouse. This greenhouse was compared to a 2 ha conventional double-layer polyethylene greenhouse using results from a linear programming model. A total capital investment of $3.1 million was required to establish the conventional double-layer polyethylene greenhouse enterprise and $4.4 million for the reject water heated glass greenhouse. The additional $1.3 million investment required for the reject water heated greenhouse included $109 000 for the specialized heating system and $918 000 for the pipeline for transferring the warm water from the power plant to the greenhouse. The conventional greenhouse required $1.5 million for annual operating costs, whereas the reject water heated greenhouse required only $1.4 million. The economic analysis revealed a positive cash flow for both systems with an annual profit of $245 948 or 9.7% for a conventional greenhouse and $194 823 or 7.7% for the reject water heated greenhouse. As a result the reject water heated greenhouse was considered infeasible at this site.
BRUMFIELD, R.G. and WALKER, P.N. (1988). FEASIBILITY OF A REJECT WATER HEATED GREENHOUSE. Acta Hortic. 223, 357-364