Application Of Electric Carbon Crystal Warming Board On Cucumber Seedling Raising And Tomato Cultivation In Greenhouse

The temperature is one of the most important and direct factors for vegetables, but it was oftenbelow the optimum growing temperature in Chinese solar greenhouse during winter. There are somewarming facilities in greenhouse such as electric warming cable, warm-air oil furnace, water orground-source heat pump and traditional coal-fired boiler but their installation cost or energyconsumption are priced beyond the affordable level. Electric carbon crystal warming board, a newwarming device applied in winter heating for civil architecture, was introduced and redesigned intosolar greenhouse for cucumber seedling raising and tomato cultivation in this experiment. The soil andair temperature, amount of growth, some physiological characteristics such as root activity, healthyindex of cucumber seedling, yield of tomato and energy consumption etc.were detected and analysed.Two methods of application of electric carbon crystal warming board named electric carbon crystalwarming seedling bed and electric carbon crystal soil-warming system were designed and tested in thisexperiment. The results showed that the electric carbon crystal warming facilities, including electriccarbon crystal warming seedling bed and electric carbon crystal soil-warming system are better thantroditional warming cable and will benefit the popularising of electric carbon crystal board in theprotected horticulture in the future. Furthermore the primary results are as follows:1. Except energy consumption rate, some thermodynamic indexes such as temperature enhancedrate, uniformity of surface temperature of electric carbon crystal warming seedling bed are higher thanthose of warming cable. Cucumber healthy index in electric carbon crystal warming seedling bed ishigher than warming cable bed and80W/m2is the best warming power density for the electric carboncrystal warming seedling bed.2. Thermal barrier is nessesary for electric carbon crystal warming seedling bed because of theirexcellent behavior in isolating heat flow and reducing energy consumption. Polystyrene board andnonwoven fabrics are both appropriate to be maken of thermal barrier.3. Electric carbon crystal soil-warming system with the board wholly buried, warming power10W/m2and warming temperature20℃is the most economic and suitable method for theadhibition ofelectric carbon crystal warming board in tomato cultivation in greenhouse. Electric carbon crystalsoil-warming system significantly enhances the soil temperature but has no influence on air temperature.Root activity and leaf photosynthetic rate of tomato are improved remarkably by electric carbon crystalsoil-warming system. Moreover, the yields and qualities of tomato are higher than those of CKrespectively. Soil temperature field in electric carbon crystal soil-warming system with the warmingpower10W/m2is better than that of20W/m2because the excessively high temperature zone in theformer is smaller. Soil temperature field in electric carbon crystal soil-warming system with thewarming temperature20℃is more economic than other temperature because its energyconsumption islower but more effective.4. Economic evaluation. The installation cost of an electric carbon crystal soil-warming system equals twice of warming cable. Both the electric carbon crystal soil-warming system and warming cableshare a higher running cost than heating by the traditional coal-fired boiler.There is a difficult and promising prospect for the electric carbon crystal warming board to beapplied in protected vegetable production because of its high cost but outstanding energy saving. Inaddition, it’s granted that installation and operating cost of the the electric carbon crystal warming boardwill be reduced with the technology innovation.