الفهرس 
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Abstract
The objective of the present study was to investigate the possibility of using the stored heat energy from the hybrid heating system (solar and biomass energies) with a heat exchanger to provide and maintain an optimum level of microclimatic conditions and evaluate and determine the most important environmental parameters affecting sweet coloured peppers during long term growth and production of the greenhouse at night time during winter season (2010-2011). Two identical gable-even-span greenhouses each have a net floor surface area of 32 m2 were used during the experimental period. The first greenhouse was connected to a hybrid heating system (biomass burning system assisted a complete solar heating system) which installed on the roof of the Agricultural Engineering Department. The second greenhouse was connected to a complete solar heating system (two solar collectors, storage tank, heat distributing system, control system) with an auxiliary heater (electric heater with actual power of 2.8 kWh) to be used during the experimental period when the solar energy was insufficient to rise the water temperature in the storage tank into 60ºC. use The hybrid heating system (biomass burning system assessed solar heating system) proved to be very efficient to provide and maintain the air temperature levels required for the sweet coloured peppers. The greatest high and low heating values are achieved from the wood of trees (24.533 and 22.487 MJ/kg) following by the grapes stalks, pear stalks, and finally the corn stalks. Therefore, 5 kg of each of; corn, grapes, pear stalks, and wood of trees were daily used in the biomass burner in order to provide high heating value of 108.466 MJ (30.130 kWh) and low heating value of 89.650 MJ (27.681 kWh). The hybrid heating system (biomass burning system assessed solar energy heating system) which connected to the greenhouse 1 provided 46.585 kWh (85.90%) of the daily total heat energy required(54.230 kWh). While, the storage tank in greenhouse 2 was taken25.165 kWh per night as supplementary heat energy from the electrical heater. Thus, the solar energy system with greenhouse 2 provided 20.223 kWh (38.32%) of the total heat energy required (52.778 kWh).The hybrid heating system provided an adequate amount of heat energy required to warm the air temperature inside the greenhouse 1, in which this greenhouse is daily heated by zero energy (no any other source of heat energy is used with this greenhouse). The weekly averages increasing rate in number of leaves inside the two greenhouses, respectively, were 3.72 and 3.87 leaf/plant. The weekly averages stem length of plants for the two greenhouses (G1 and G2) were 4.32 and 4.04 cm/week, respectively. The maximum lengths of the sweet coloured peppers plants inside the two greenhouses were 203.2 and 189.7 cm, respectively.The number of fruits being seated on each plant within the two greenhouses (G1 and G2) were on the average 26.4 and 24.8 fruit, respectively. Some of these seated fruits approximately 37% were eliminated according to the breading policy of the sweet coloured peppers. The total fresh yield of sweet coloured peppers crop for the two greenhouses (G1 and G2) respectively, was 211.027 and 189.687 kg. The total annual costs included the three different items (greenhouse construction, solar heating system, and operating costs) were about L.E. 1824.25 However, the total costs per square meter of greenhouse were L.E. 57.01. The fresh yield of sweet coloured peppers per square meter was 6.595 kg/m2, which sold by L.E. 79.14. Consequently, the estimated return on capital was 38.82% per annum.