|
Activities
Greenhouse Heating Systems
Greenhouse heating systems
should be selected based on the size and
type of greenhouse
structure, the type of plants growing in the house,
the location, and the ability of the system to
provide a uniform thermal environment for plants.
Both unit and central heaters are available for
greenhouses. The system choice will depend on the
available fuel type, initial and operating costs,
grower preference, and greenhouse size.
Unit
Heaters, which use
forced air, may be gas or oil fired. These heaters are
better suited for smaller greenhouses. The use of poly
tubes to distribute heat more evenly minimizes
temperature fluctuation. Unit heaters must be properly
vented to the outdoors.
Central Heating, which uses hot water or steam, is preferable to having
many small heaters distributed throughout the greenhouse
space in large greenhouse operations. Hot water or steam
heating systems can also be used to preheat irrigation
water and prevent cold-water shock to plants.
The heat is centrally
provided by the boilers and transferred to the
greenhouse environment either by pipes that are smooth
or finned or by unit heat exchangers equipped with fans.
Pipe/Rail Heating
Systems
maintain uniform temperatures and positively affect the
microclimate of plants. Air movement caused by the
warmer pipe/rail reduces the humidity around the plant.
Such systems are suitable for vegetable production
systems.
Underbench Heating Systems
maintain uniform temperatures and positively affect the
microclimate of plants. Air movement caused by the
warmer underbench pipe reduces the humidity around the
plant. Such systems are suitable for plants grown on
benches, fixed tables, rolling, or transportable tables.
In-Floor Heating Systems,
also called radiant heating systems, maintain uniform
temperatures and positively affect the microclimate of
plants, and significantly reduce energy cost. Air
movement caused by the warmer floor reduces the humidity
around the plant. Such systems are suitable for plants
directly grown on the floor, flooded-floor areas or work
areas.
Overhead Heating
Systems can provide the
additional heat required for winter months. Such
systems are compatible with hanging basket areas,
snowmelt systems, and mono- or duo-rail systems.
Both bare and finned pipe applications are common.
Perimeter Heating Systems
- Pipe/rail, underbench,
and in-floor heating systems usually cannot supply the
level of heat demanded during cold winter months, and
require supplemental heating. Perimeter heating can
partially provide the additional heat required and
contribute to a uniform thermal environment in the
greenhouse. Both bare and finned pipe applications are
common.
|
