Research exploring greenhouse environment control over the last 50 years

Abstract

Environments do not exist in isolation. Their main components in greenhouse systems are plants. Without consideration of plants, analysis of greenhouse environments and environmental control of greenhouses can be accomplished, although it is not simple to achieve. Initial attempts were undertaken to analyze greenhouse environments and then reproduce them. Ventilation rate effects on plant photosynthesis in a growth chamber were reported in 1966. Computer simulations then became a main subject of research. The first dynamic computer simulation of a greenhouse environment including plants was published in 1971. According to innovations of computer technology, the use of minicomputers and microcomputers spread in many areas. By measuring the net photosynthesis of lettuce plants grown under artificial lighting, air temperature was optimized using a minicomputer with the hill-climbing method. The method was designated as the Speaking Plant Approach to environment control (SPA). After the author developed the first reported environmental control system in Japan, systems using microcomputers spread widely for greenhouse environmental control. Knowledge-based expert systems were tested for plant management. Also, a machine vision system was developed to detect critical moments for watering of muskmelon plants. The first feed-forward control method for greenhouses with a large heat mass was reported. Then space farming was tested in 1996 to assess gravity effects on plants. Energy-saving aspects such as solar sterilization, ground heat storage system, and storage using phase change material (PCM) have been reported. Defects of ordinary solarimeters were reported in 2008 along with an approach to estimate evapotranspiration in a greenhouse without the effect of so-called cosine law. Later, this technique was expanded to estimate photosynthesis of the plant canopy in a greenhouse using newly developed sensor units.

Wind pressure acting on greenhouses: A review

“…Greenhouses are designed to provide a suitable environment for the growth of plants annually [91,92] . One of the key factors controlling the greenhouse environment is ventilation [93] .…”

Modeling and simulation of temperature control system in plant factory using energy balance

“…where, m is the internal air mass, kg; m = ρ a • V; V is the indoor volume, m 3 ; ρ a is the indoor air density in kg/m 3 , and ρ a = 1.199 kg/m 3 for the air in a plant factory; c ap is the specific heat of air at constant pressure, and the c ap =1.009 kJ/(kg•°C); ∆t is the change rate of internal temperature, °C/s; t a is the indoor temperature, °C.…”

“…There are some incorporating features of plant factories, such as artificial lighting and active cooling, particularly on the excellent hermetic seal, tunable light intensity, forced circulation channels of internal air, and high CO 2 absorption rate [2] . Currently, the switching control system is commonly used to manipulate the artificial lighting, temperature, humidity, CO 2 concentration, and nutrient solution in most facilities of plant factories [3][4][5][6] . However, the input and output signals of various parameters always vary in constant impulse [7][8][9] , easily resulting in power loss and annual maintenance cost of the equipment [10] .…”

Design and experiment of the environment control system for the industrialized production of Agaricus bisporus

“…At present, greenhouse environment regulation technologies are sophisticated and mature [9,10] , where hardware has developed from single machine control [11] to the Internet of things control [12] ; control factors have developed from single temperature regulation [13] to multiple factors coordinated regulation such as temperature, light, water and ventilation [14] , and environmental regulation methods have gone through single environmental factor control [15,16] , integrated environmental control [17] , model-based decision-making control [18] , economic optimal control [19] , crop information feedback optimal control [20,21] and other development stages, the control methods are more and more diversified [22] .…”