Geothermal Heat for Greenhouses
Geothermal heating systems capture heat from the sun and can store this thermal energy which can be utilized in the greenhouse at night when temperatures tend to be colder. This type of greenhouse system can improve your energy efficiency by reducing heating costs and extending your growing season.
Using Geothermal Heat
The concept of using the earth as a natural temperature regulator has been around for thousands of years. In ancient Persia, for example, underground aqueducts called qanats were used to channel cool air into buildings during hot summers. Similarly, in ancient Rome, wealthy citizens would build subterranean rooms called hypocausts, which were heated by hot air from fires that were burned outside and circulated through pipes.
Utilizing soil (earth battery) to store and release energy either in the form of heat or cool air to regulate the greenhouse creating an ideal growing environment for plants has a fascinating history that dates back to ancient civilizations.
In the late 19th and early 20th centuries, earth battery greenhouses became increasingly popular in Europe, particularly in France and Germany. These structures were typically built by digging a trench into the earth, lining it with stones or bricks, and covering it with a layer of soil. A greenhouse frame was then built on top of the soil, and the trench served as a natural insulation system, keeping the temperature inside the greenhouse relatively stable.
In the Mid-20th century, earth battery greenhouses fell out of favor as modern heating and cooling systems became more widespread. However, in recent years, there has been a resurgence of interest in these geothermal systems, particularly among environmentally conscious gardeners and farmers looking for ways to reduce their carbon footprint and energy costs.
Today, there are many designs and variations of earth battery greenhouses, ranging from small backyard structures to large commercial operations. Ceres Greenhouse Solutions designed a geothermal climate control technology for their commercial greenhouses called a GAHT® (ground-to-air heat transfer) System. The GAHT® system was designed to be built with a Ceres passive solar greenhouse. The GAHT® has proven its effectiveness to maintain comfortable growing conditions, year-round, at a fraction of the cost of a traditional HVAC system.
Sunglo has exclusive rights to use this technology for our residential greenhouse kits, called GAHT® Lite. GAHT® Lite comes with the Winter Package, see details on the greenhouse kits detail page. The GAHT® Lite’s piping is installed in a U-shaped raised bed (see graphic) so no significant digging is required. Having a GAHT® Lite installed in your Sunglo greenhouse will help it stay warm in the winter at a lower cost than a greenhouse without a GAHT® system.
How does the GAHT® Lite work?
It works by taking the free heat generated by the sun trapped inside the greenhouse on even the coldest days and bringing that heated air into the soil (earth battery) in the raised bed of the greenhouse. During the day, a thermostat-controlled small fan pulls the heated air into irrigation piping buried in the raised bed. The buried pipe efficiently distributes the heat into the soil.
Heating the Rootzone
Storing heat in the soil keeps the plant roots warm at night. This heat energy also transfers back out of the soil, reheating the air inside the greenhouse and delaying the need for a secondary backup heater to turn on, thereby decreasing the run time and the energy costs associated with using that heater.
Most importantly, warming the root zone will provide the heat necessary to protect the plant and its canopy regardless of the air temperatures that dip inside the greenhouse. For most plants, the soil temperature is more important for growth, improving water and nutrient absorption. This means you will have healthier and happy plants during periods of cold weather.
Even if you prefer not to grow directly in a raised bed, you should consider the benefits of GAHT® Lite. By installing greenhouse benching above the raised beds, you will still benefit from the stored heat in the soil.
In conclusion, earth battery greenhouses have a long and fascinating history that spans thousands of years. From ancient Persia and Rome to 19th-century France and Germany, people have recognized the value of utilizing the earth’s natural temperature regulation to create ideal growing conditions for plants. Today, incorporating geothermal systems into structures is experiencing a renaissance as people look for more sustainable and eco-friendly ways to grow food and plants.
Geothermal heating works best in a highly insulated and tightly sealed greenhouse environment. You can take advantage of geothermal heat when you order a Sunglo Greenhouse with the Winter Package which has been designed with three layers of High Impact Acrylic to form a 1.43-inch air space giving a Sunglo Greenhouse a high R-value. The larger the R-value means it can better keep out the winter cold or summer heat.
Even a GAHT® Lite heated greenhouse may require a backup heater for those extremely cold days with minimal sun. That is why we also include a thermostat-controlled Infrared Heater. This unique heater heats the plants, not the air, so it is much more efficient than a standard electric heater that needs to heat the air of the whole greenhouse and much safer than a heater that burns propane, kerosene, and even an electric heater. Check out our Blogs on Greenhouse Heating to learn more. https://sunglogreenhouses.com/blog/
If you would like to purchase a Sunglo Greenhouse and need additional information regarding our greenhouse kits with the GAHT® Lite or would like to speak with someone who owns a Sunglo Greenhouse, contact us at firstname.lastname@example.org or by calling (720)-443-6761.