Design procedure for a greenhouse space heating system utilizing geothermal warm water

Utilization of warm geothermal water (40°–60°C) supplied from deep wells for heating of winter crops is being pursued in the Arava region of Israel. Systems for soil warming have been developed and tested. This paper describes the design procedure of a space heating system utilizing warm water. Polyethylene irrigation piping on the crop bed is used for heat exchange. The design, based on conventional heat transfer formulae and computer simulation, resulted in a series of curves that facilitate future practical designs. An example, utilized in commercial plots, demonstrates the calculation procedure with respect to the special problems of medium salinity geothermal water used for irrigation.