Solar Greenhouse Heating
We have several ways of using the sun to heat greenhouses and crop drying sheds.
You may choose to use a single one, or a combination of any of the following methods:
1. Root-zone solar heating.
Root zone solar heating is laid out on the benches in a greenhouse or plant nursery, and keeps the plant root zone warm. It therefore keeps the plants propagating and growing much more quickly.
Heated water is pumped through the matting to ensure that the root zone of the plants remains at a constant warm temperature throughout the night.
The circulating water may be heated by solar energy, gas or electricity.
Substantial savings to heating costs have been found by using this root zone heating method, as there is normally no need to heat the entire greenhouse.
By keeping the roots and soil at the right temperature, plants are relatively unaffected by small variations in air temperature within the greenhouse.
The unique features of this heat transfer mat ensure good heat transfer from the flat mat surface to the plant pots, and it can be neatly installed with plumbing at only one end of the propagation benches, whilst allowing for different temperature zones within the greenhouse by using flow control valves.
Each heating strip consists of 10 flattened tubes connected immediately adjacent to each other so there is good heat transfer to the plants. Each strip is 160 mm wide, and the strips are laid side by side to cover the bench. Each end of the strip is joined to a PVC pipe using a 10-barb manifold that plugs into the PVC pipe via a rubber grommet. Installation is simple, and there are no leaks.
Complete & detailed installation instructions, including plumbing diagrams, are supplied with every greenhouse heating kit.
|Rootzone Heating Mat per roll (25 m long x 0.16 m wide) 4 sqm||$180|
|Manifold & grommet (1 per strip)||$10|
|PVC drilled in & out pipe set (1.2 m)||$45|
|PVC drilled return pipe (1.2 m)||$45|
|Circulation pump (750 watt)||$599|
|Automatic temperature controller||$470|
Typical cost for a heating mat to cover a 6 metre x 1.2 metre propagation bench is around $445 including manifold pipes.
2. Solar Evacuated tube water heating collectors
Water can be heated during the day to store as heat for the night in a large 1000 litre stainless steel storage tank. The heated water may also be circulated through the greenhouse during the day to increase the temperature of other thermal mass (eg rock piles) in the greenhouse.
|Solar heating components and prices – May 2017|
|60 tube evacuated tube solar collector with central manifold and stainless steel frame||$1899|
|1000 litre stainless steel heat exchange storage tank (uninsulated)||$2999|
|Titanium heat exchanger 16kw (55 btu/hr)||$699|
|Titanium heat exchanger 45kw (155 btu/hr)||$989|
|Header tank for use with 60 tube manifold solar collector||$165|
3. Solazone Air heating collectors
- Solazone large solar air heaters, suitable for drying crops in a shed, or heating an area.
- The collectors are made from colorbond steel boxes, with heavy duty glass tops.
- Size : 1450mm x 2000mm, can be used individually, or fitted together in an array.
- Air is circulated with a solar-powered fan, with optional grid back-up, if required.
|Solar Air Heater details and Prices May 2017|
|Solar Air Heat collector (2.8 sqm)||$899|
|Extractor pipe manifold||$65|
|Solar Heat extractor fan 16w 12v with panel||$425|
|Insulated 150 mm duct 6m long||$150|
|Night operations pack||$165|