ENERGY-CONSERVATION IN GREENHOUSES WITH BURIED PIPES

The use of buried pipes reduces the energy consumption for heating of agricultural greenhouses by increasing the air temperature and also im proves indoor conditions by reducing temperature fluctuations during t he day. A parametric analysis has been performed for a typical glass g reenhouse to illustrate overall system performance. The greenhouse-air temperature increases during the winter with increasing pipe length, decreasing pipe diameter, increasing depth up to 4 m, and decreasing a ir velocity inside the pipes. Measured data from a 1000-m(2) fibreglas s greenhouse with four buried pipes are found to be in good agreement with calculated values.