Heating and Heat Distribution
Heating and Heat Distribution Systems in a Greenhouse Environment.
Greenhouse Heat Generation
Passive heating can be optimized with heat sinks, clean glass, proper aspect and orientation of the greenhouse design, etc. The idea of a heat sink is just a mass, insulated from the floor and external walls, that can absorb daytime radiated heat energy and re-radiate that heat back at night. Most commonly, supplemental heat is generated with petroleum resources — save where alternatives, like geothermal energy, can be harvested. Because of rising fuel costs, there is a huge interest in alternative ideas for high energy efficiency and conservation.
Greenhouse Heating Pipes
Greenhouse wall with flow controls in pipes placed on the walls help heat the greenhouse and distribute hot water. Greenhouses are heated in multiple ways. Hot water can be distributed through pipes below the floor, just above the floor, in the beds, on the ceiling, etc.
Heat Distribution
Overhead, buried, wall, underground or underbench
pipes and tubes, with the help of turbines and fans, distribute air, steam and water
to distribute heat energy and maintain uniform heating throughout the greenhouses. Heating
distribution and temperature uniformity are critical for harvest quality and crop
timing for market.
Greenhouse wall with flow controls in pipes placed on the walls help heat the greenhouse and distribute hot water. Greenhouses are heated in multiple ways. Hot water can be distributed through pipes below the floor, just above the floor, in the beds, on the ceiling, etc.
Horizontal airflow fans (HAF), fans designed to move air and hung above the crop on cross braces, provide circulation for temperature uniformity, as well as, a reduction in condensation which can lead to foliar diseases. Additionally, during the sunny days HAF fans can aid in cooling and introduce air with higher Carbon Dioxide levels near leaves. HAF fans run 24/7 except when vents are open or exhaust fans are running. Horizontal airflow fans are purchased or fitted with a housing, aka shroud, where increased airflow is needed.
Insulation and Heat Reflection
Insulation and heat reflection are important, eg at night, to prevent any undesirable loss of heat energy. Without greenhouse thermal screens, or thermal blankets, employed nocturnally, convection currents can carry heat to greenhouse glass where heat will be conducted rapidly out of the greenhouse. Heating, heat distribution and heat energy conservation are critical factors in greenhouse farm management. Reducing heat loss is generally achieved with insulation covering or intrinsic to floors, walls, greenhouse framing and greenhouse glass.Substantial savings are achieved with the use of thermopane glass or double covering windows that trap air in a small space between panes or between polycarbonate for insulation. Care has to be taken not to allow moisture to build up within the double covering or thermopane whereby fogging can occur reducing solar insolation.