Sustainable greenhouse design and modeling

Abstract

Controlled Environment Agriculture (CEA) ― food production in greenhouses ― is recognized to be an important strategy for meeting the growing food demand in the U.S. and worldwide. The controlled environment of a greenhouse allows for production of crops in a variety of climates worldwide and year round. Unfortunately, conventional greenhouses consume more fossil fuel energy in the operation of mechanical systems than other similar sized buildings, and therefore have larger carbon footprints. Greenhouse operation is challenging because the crops require control of CO2, and moisture as well as temperature and because light-weighted construction makes the greenhouse environment susceptible to climate and outdoor weather conditions. These challenges brand greenhouses as one of the most energy intensive sectors of the agricultural industry, and thus, have become a great area of focus for energy efficiency research. Thoughtful design and energy efficiency strategies for greenhouses can help to mitigate large energy requirements. This Report presents research on CEA beginning with a discussion of CEA as compared to open-field agriculture and a literature review of environmental control technology in agricultural greenhouses. This is used to inform and direct research on simulation of the greenhouse environment and the use of EnergyPlus, a building simulation software, to accurately represent the greenhouse environment. Finally, a specific case study is examined in which EnergyPlus is used to gage the potential of waste heat utilization for greenhouse heating. This research identifies areas in which future research has the potential to reduce greenhouse energy consumption and improve control operation in order to employ greenhouse food production as a major component of the agriculture industry.