Passive Solar Greenhouse Heating Compare Different Types of Solar Heating
Passive Solar greenhouse heating: choose the most suitable for your project
Choose the right type of passive solar greenhouse heating for your greenhouse project.
There are 3 types of passive solar greenhouse:
- photovoltaic greenhouses or PV greenhouses
- greenhouse heated with solar thermal panels
- passive solar greenhouse or bioclimatic greenhouse
We’re going to compare the heating of these types of passive solar greenhouse.
1. Photovoltaic solar greenhouse or PV greenhouse
The photovoltaic solar greenhouse roof is made up of photovoltaic panels that produce electricity for either self-consumption or resale.
Photovoltaic greenhouses are generally built with an east-west orientation, and can be asymmetrical to maximize the south-facing, photovoltaically productive surface area, and thus improve profitability.
As a result, less light enters the greenhouse and less photosynthesis is generated.
Photovoltaic greenhouses are suitable for plants requiring low photosynthetic radiation (PAR) and low DLI (Day Light Integral), such as:
- Ginger
- Ginseng
- Chicory
- Vanilla
- Watercress….
But photovoltaic greenhouses are not suitable for plants requiring high DLI (Day Light Integral) such as:
- Tomato
- Cucumber
- Sweet Peppers…
This type of passive solar greenhouse generally has no heating system.
Our Agrithermic design office carries out simulation studies of the photosynthetic radiation (PAR) and solar radiation reaching the plant canopy in a photovoltaic greenhouse over a year at hourly intervals, depending on:
- the type of solar panel and its location in the greenhouse
- greenhouse size (orientation, length, width)
- GPS coordinates of the site
This makes it possible to estimate agricultural production as a function of greenhouse architecture, solar panel type and location on the greenhouse.
2. Heating a solar greenhouse with thermal solar panels
Thermal solar panels produce hot water. The energy from this hot water is stored in a large tank (open buffer) to be released when the greenhouse needs to be heated and dehumidified.
As greenhouses generally need more heating in winter than in summer, and solar energy is more important in summer than in winter, the match between needs and resources is not optimal. Solar thermal panels can rarely meet all heating needs.
In general, 30% of the ground surface area can produce 30% of annual heating needs. With this type of sizing and subsidies, solar thermal is a very competitive energy source for producing this heat.
Our Agrithermic engineering office carries out feasibility studies using Hortinergy software.
3. Passive heating of a passive solar greenhouse
A passive solar greenhouse stores solar energy during the day by capturing sunlight through its transparent surfaces. This energy is then released as heat during the night or on cloudy days, helping to maintain a stable temperature for plant growth. The structure is well insulated to minimize heat loss and maximize energy efficiency. Unlike active systems, a passive solar greenhouse does not rely on solar panels or external heating sources, making it a low-cost and sustainable solution for year-round cultivation.
This site shows the Thermitube principle. Other types of passive solar greenhouses can be found at serre-bioclimatique.fr
