Source and background of the topic:

For a long time, the wall construction of solar greenhouses has mainly consisted of various dry-built earth walls and brick walls. It mainly relied on transparent covering materials for the front roof for lighting and ventilation, and covered with straw curtains and insulation quilts for night insulation. Heat storage of walls, ground and air maintains the greenhouse at night. This solar greenhouse has low self-regulation and control capabilities in the coldest seasons and extreme weather conditions. Without additional heat replenishment, freezing damage often occurs. In recent years, due to abnormal winter climate change, freezing disasters have generally occurred in solar greenhouses across the north. Moreover, in order to improve the insulation performance of the greenhouse, a back roof is built on the back wall of the greenhouse to increase the insulation performance of the greenhouse. This structure is very beneficial to the insulation performance of the greenhouse, but the unfavorable factor brought by the back roof is that it is greatly reduced. The light intensity at the back of the greenhouse is very unfavorable to the growth of crops in the solar greenhouse. Especially after winter, the lack of light conditions is very unfavorable for crop growth. If we can make full use of the illumination resources with sufficient sun in the north, while daylighting the solar greenhouse during the day, the solar heat collection equipment in the solar greenhouse is activated to collect excess heat in the greenhouse. When the temperature is low at night, the collected heat will be released to warm and replenish the greenhouse, creating a greenhouse environment with high controllability, good heating effect, and is conducive to crop growth, which will be very beneficial to the growth of crops in the solar greenhouse. It is also an effective way to prevent frequent freezing injuries in solar greenhouses and overcome the poor ability of solar greenhouses to control the environment in winter.

Technical principles and performance indicators:

In order to solve the above technical problems, the present invention provides a solar dual-effect solar greenhouse and a construction method thereof. The greenhouse has good lighting capacity and strong thermal insulation effect. It has both passive heat storage capacity of ordinary solar greenhouses and active heat storage capacity. It has good thermal insulation capacity in winter and good lighting performance in spring, summer and autumn. The invention is mainly realized by the following methods: it mainly comprises transparent solar greenhouse walls on the east, west and north sides, namely gables on both sides, back walls and back roofs. Two water tanks are installed in the greenhouse, namely, a high temperature water tank and a low temperature water tank, which are mainly used for collecting and storing heat by the solar heat collection system. In addition to passive heat accumulation through the greenhouse ground and air, this greenhouse also installs multiple sets of solar active heat storage system to actively collect solar energy. The technical scheme is as follows: it includes a transparent wall, a transparent lighting surface, a water curtain solar panel heat collection system, a high and low temperature water tank, a smoke-drying water bag, a floor heating coil, a central control system, a dual-source heat pump heat exchange system and a solar energy collector heat storage system. The transparent wall is provided with polystyrene foam particles that can be filled and extracted, which are filled in winter and extracted and transparent in spring. Through the central control equipment to carry out environmental control and management of the solar active heat storage system, each heat storage and release system can be used centrally and independently in ordinary greenhouses. Compared with ordinary greenhouses, the lighting amount of dual-effect solar greenhouses is increased by 15%, the minimum temperature is increased by 3-5 ° C, the ground temperature is increased by 4.2 ° C, and the land utilization rate is increased by 20%, comprehensively improving the environmental conditions of existing solar greenhouses.

Creativity and advancement of technology:

Compared with ordinary solar greenhouses, the creativity and advancement of this technology mainly reflect the following aspects:

1. The greenhouse is of an assembled type as a whole. The greenhouse structural skeleton and accessory materials can be standardized and factory-produced. The installation is simple and fast, and it saves land.

2. The wall can achieve full light transmission. The greenhouse wall and back roof both adopt transparent + insulation structures. In low temperature seasons, high insulation materials are filled or covered in the transparent structure to improve the insulation performance of the greenhouse. In spring, the insulation materials are removed to achieve full light transmission and change the greenhouse wall structure to transparent.

3. Integrate a variety of solar active heat storage and release systems (water curtain solar heat storage system, dual-effect heat pump heat exchange system and water-bag solar heat storage and release system), using water as the medium to realize active and passive solar energy in solar greenhouses. Combined utilization of heat storage, and solar active heat storage and release systems can also be applied separately in ordinary solar greenhouses.

Technology maturity, scope of application and safety:

The research on dual-effect solar greenhouses and supporting technologies has fundamentally changed the shortcoming of the original solar greenhouses that can only rely on passive heat storage for production, greatly improving the comprehensive performance of energy-saving solar greenhouses, improving greenhouse environmental control capabilities, and enabling solar greenhouses. The ability to resist disasters and increase production has been greatly improved. Secondly, the prefabricated installation of the greenhouse structure and the construction of light-transmitting insulation walls not only simplify the construction process of the solar greenhouse, but also greatly improve the utilization rate and land use rate of the solar greenhouse. Therefore, the overall technology of the project and supporting solar active heat storage and release equipment have good application prospects. The greenhouse disclosed by the invention effectively improves the ambient temperature of the solar greenhouse at night, and the heat accumulated by the active heat storage equipment can be effectively released for a long time, which is very obvious for ensuring safe production of the solar greenhouse in winter and improving the controllability of the solar greenhouse environment. Through technical research and development and practical application, this technology is already in the pilot stage, in which solar active heat storage equipment has been applied to ordinary solar greenhouses, and for new greenhouses, the wall insulation method of the invention can be used for construction.

Application status and existing problems:

The solar active heat storage equipment developed by the invention has been applied to ordinary solar greenhouses to increase temperature and replenish heat in winter, can increase the minimum winter temperature of ordinary solar greenhouses by 3-5℃, and effectively guarantee the winter production of existing solar greenhouses. The main problems are: in the research on transparent wall structures of solar dual-effect greenhouses, although the developed wall structure can achieve all-light type, the extraction operation of polystyrene foam particles filled in the wall is not convenient enough, and the use is limited. There are many factors, which is not conducive to widespread application in production. In terms of future improvements, it is planned to use multiple layers of thick composite insulation materials for wall insulation. When full-light greenhouse types are needed, the insulation materials will be rolled up or removed to achieve full-light lighting in the greenhouse.