Masonry Heaters for Greenhouses

Masonry Heaters for Greenhouses.

Driven by a desire to lengthen growing period in greenhouses, farmers and gardeners try to find a suitable heating system. Although there are different common heating systems and devices available, most of them aren’t suitable for greenhouses specific conditions, as they don’t possess several specific characteristics:

Safe and “user friendly” operation
Minimal supervision required with possibility to leave unattended for several days.
Maximum efficiency
Minimal pollution
Usage of renewable energy sources (fuel)
Capability to absorb solar energy at daytime and release at night
Even heat pattern without “too hot – too cold” cycles.
Ability of a system to prepare hot water
Low operational costs
A solution that has all the features mentioned above, is masonry wood burning stoves (masonry heaters) designed specifically for greenhouses. The best way to go is to design a greenhouse itself in a way that it will use solar and combustion energy most efficiently. Here is a proposed solution:
A greenhouse has to be positioned with its longest side facing south. The southern, western, and eastern walls have to be glazed the normal way, but the roof has to be sloping to the south. The north wall should be made of dark colored masonry (or be painted in black) with insulation on the outside. A firewood storage place can be organized behind the north wall. A masonry heater with hot water coil has to be built into the masonry wall or has to be attached to the wall. The heater I propose here will:
Heat a greenhouse without loosing heat to the outside.
Heat water. Hot water coil will not lower combustion temperatures, as it is not located directly in the firebox.
Use wood as renewable and inexpensive fuel
Use electricity as a back-up energy source
Be very efficient and economical
Have its lower part heated hotter than the upper part, that results in even heat pattern with an accent on heating the soil.
Our heater is a “double-bell” stove built by principles of “free movement of gases”. The stove is designed according to Russian standards and building codes. Working drawings are attached. Molded brick 250x120x65mm with 5mm joints is used in the outer shell. Firebrick 250x124x65mm (laid flat and on the edge) used in the firebox section. A 5-10mm expansion joint is maintained between the firebox and the outer shell. The joint is filled with ceramic wool. Two electric heating element of 1-1.5kVt each are used in the heater. Each element is connected through a separate fuse. The heater and hot water coil are designed to produce 120-180L of water at 40 degrees Celsius. Chimney’s height for this heater is 5m. The first firing of the heater has to be done with a by-pass damper located in row # 17. The damper should be gradually closed after.
Working drawings
Igor Kuznetsov
03/2003 © Igor Kuznetsov "Kuznetsov's stoves"