How it Works

Theory of Operation--

Several factors working together make the HELPS stove efficient, safe and convenient. The cast concrete stove body is molded in fiberglass molds, providing a fast low cost way of producing a long lasting, low cost stove body.  The body, however only provides structure for the stove.  Two main factors make the stove fast heating and fuel efficient.

Complete combustion—In order for all energy in the wood to be converted to hot gases, it must be completely burned including the oil vapor that normally would be emitted as smoke.  Containing the fire in a insulated combustion chamber allows the fire to burn hot enough to consume the oil vapor.  Smoke is wasted fuel.  It is also a health hazard both inside and outside the house. 

The photo on the left shows a stove housing with the clay combustion chamber but without the insulation. In the middle is a photo after the insulation has been added.  Note the square opening of the combustion chamber and also the rectangular slot along the back that collects the hot gases and vents them to the outside through the chimney. As the gases pass back from the combustion chamber to the collection slot, they heat the plancha (metal stove top not shown in the middle photo). On the right are the stoves with plancha added.

The insulation is pumice, a volcanic rock that is a very good high temperature insulation and quite cheap. 

Burning the wood inside the insulated chamber creates a gas temperature that exceeds 1400 degree F.  At these temperatures, the gas vapors (smoke) ignite, adding energy to the fire, and are eliminated from the exhaust.

Efficient transfer to the pot—Once the energy from the wood has been efficiently transformed to hot gases, it must be efficiently transferred to the pot.  Energy that heats the stove body and is exhausted to the chimney is energy not available for cooking.  Wood ashes or pumice provides insulation that prevents the heat from being wasted heating the stove body.  Hot gases that do not touch the plancha also waste their energy.  The insulation fills the stove cavity to within 1 inch (2.5 cm) of the metal plancha.  In this way, all the hot gases come in contact with the cooking surfaces thereby transferring their energy to the pot and leaving only enough heat in the exhaust gases to provide a draft up the chimney.

Wood management such as drying the wood and splitting it to proper size is taught by the HELPS stove technicians.

Due to complete combustion, efficient heat transfer. and wood management, the wood consumption (and carrying) is reduced by 60-70%.