Energy Saving in Greenhouses: Optimal Use of Climate Conditions and Crop Management

Abstract

In the last few years, energy consumption in greenhouses has gained increased interest, due to the liberalisation of the energy market and the increasing prices of natural gas. In this paper, the effects of a series of adaptations in greenhouse climate and cropping systems on crop production and energy consumption are presented. Greenhouse energy consumption is primarily determined by the temperature set points. Allowing temperatures to fluctuate, can conserve 3-13% energy, depending on the bandwidth applied. If average temperatures were kept at set point values, it hardly affected plant production. Lowering the temperature set point by 2°C reduced energy consumption by 16%, and production by 3%. Increasing relative humidity set points and reducing plant transpiration by removing leaves or applying antitranspirants could save approximately 5% energy with hardly any effect on plant growth. Increased light transmission of the greenhouse increased plant production and slightly reduced the energy consumption. Filtering out NIR had a positive effect on plant production, but negatively affected greenhouse temperatures. Substantial energy conservation could be realized by the application of an energy screen (16-20%). Optimal use of the available amount of CO 2 positively affected crop production. These results indicate that in present cropping systems, energy conservation of 25-30% seems possible without major investments and without loss of production. Characteristics of such an energy efficient cropping strategy are the use of relative low temperature set points, high humidities, use of energy screens and fluent transitions in greenhouse climate.

Comparison of Climate and Production in Closed, Semi-Closed and Open Greenhouses

“…However, acclimation of photosynthesis and production to high CO 2 concentration may occur (Besford et al, 1990;Peet et al, 1986). Dieleman et al (2006) found in current Dutch greenhouse systems, photosynthesis and production did not show adaptation to high CO 2 concentration.…”

Evaluation of Compressor Heat Pump for Root Zone Heating as an Alternative Heating Source for Leafy Vegetable Cultivation

“…Reducing energy consumption for heating has therefore become an important challenge. Many efforts have allowed the optimization of the daily average temperature and humidity as well as that of solar radiation and CO 2 concentration [4][5][6]. Furthermore, studies have proposed innovative strategies such as structural design, the use of energy-efficient covers, improved heating and ventilation systems, management of indoor micro-climates and use of renewable energy sources based on the location of greenhouses.…”

Effects of Cover Whitening Concentrations on the Microclimate and on the Development and Yield of Tomato (Lycopersicon esculentum Mill.) Inside Mediterranean Greenhouses

“…Leaf photosynthetic rate is determined by the amount of photosynthetic protein per leaf area and CO 2 conductance in stomata [9]. In addition, a rise in the cover transmissivity allows not only to increase photosynthesis and production, but also to reduce the energy input in cold periods [10]. Under normal CO 2 concentrations and with adequate temperature conditions, photosynthetic activity is mainly affected by light intensity [11].…”