Compost heater silo (prototype): Difference between revisions

Revision as of 20:28, 21 October 2018

This article describes the prototype of a compost heater silo, which is the heart of an internal Compost heater, in an early development state.

The prototype on the photograph on the right has been build by modifying a usual rainwater tank (polyethylen). It is 1.80 m high at a volume of 300 liters. This is too small for a substantial contribution for the heating requirements of a regular dwelling house, however its purpose is the analysis and optimization of the system's behavior, a feasibility study.

The prototype has an inlet for the biomass and an outlet for the resulting compost. There are 5 additional glass windows for observation and possible manual intervention. The air inlet and outlet are made from HT waste water pipes (polypropylen). Ports for water heating have been prepared, but are not yet used.

The prototype was started in October 2017 in a frost-free garage. After a one year trial the prototype was modified and moved into the basement of a dwelling house, where the conditions are nearly the same as in the intended use.

Start of the First Trial

Biomass filled in: shredded bush, foliage, bio waste from the kittchen. Two buckets of half rotten compost were added to give the decay process a good start. This included many invertebrates who multiplied thereafter:

Experiences with the Prototype

Details of the windows, view from the outside

Details of the windows, view from the inside

The air permeability of the biomass is good enough, even without special means to increase it. The initially built in grids have been removed after a few weeks.
The surrounding temperature is important. The decay slows down below 10°C, which is caused by the slim shape of the silo in this case. The heat is too easily radiated by the large surface.
The moistness must be high enough to support the microbes optimal. The biomass should be dripping wet.
Removal of the compost is not necessary in any case, because the decay process is continued down to water, dissolved minerals and carbon dioxide if the moisture is high enough.
The air ventilation does not work with the own convective pressure in this prototype. This again can be due to the slim shape. Therefore, an additional gentle push is required. Placing the air outlet on an appropriate location of the roof is good enough, letting the wind pressure do the work.
If thuja or other biomass with strong aromatic oils is put in, the microbial activity is impeded and the temperature declines. This effect is subject to further studies. It may be useful for pausing the decay process during the warm summer months.

Modifications after the First Trial

The prototype was modified in July 2018 to make it ready for the second winter. All ports have been reinforced by a waste water coupler and carefully sealed. An additional pipe has been fed through the silo for water heating. The silo has been placed in a warmer location in a dwelling house, where the surrounding conditions are nearly the same as in the intended use. The air inlet has been corrected to the breather pipe of an existing waste water canal.

@@ Line 5: / Line 5: @@
 The prototype on the photograph on the right has been build by modifying a usual rainwater tank (polyethylen). It is 1.80 m high at a volume of 300 liters. This is too small for a substantial contribution for the heating requirements of a regular dwelling house, however its purpose is the analysis and optimization of the system's behavior, a feasibility study.
-The prototype has an inlet for the biomass and an outlet for the resulting compost. There are 5 additional glass windows for observation and possible manual intervention. The inlet air and outlet air are made from HT waste water pipes (polypropylen). Ports for water heating have been prepared, but are not yet used.
+The prototype has an inlet for the [[biomass]] and an outlet for the resulting [[compost]]. There are 5 additional glass windows for observation and possible manual intervention. The air inlet and outlet are made from HT waste water pipes (polypropylen). Ports for water heating have been prepared, but are not yet used.
 The prototype was started in October 2017 in a frost-free garage. After a one year trial the prototype was modified and moved into the basement of a dwelling house, where the conditions are nearly the same as in the intended use.
-==== Start of the first trial ====
+==== Start of the First Trial ====
 Biomass filled in: shredded bush, foliage, bio waste from the kittchen. Two buckets of half rotten compost were added to give the decay process a good start. This included many invertebrates who multiplied thereafter:
-* Redworms
+* [[Redworm]]
-* Common rough woodlouses
+* [[Common rough woodlouse]]
-* Snails
+* [[Land slug]]
-==== Erfahrungen, die mit diesem Prototyp gewonnen wurden ====
+==== Experiences with the Prototype ====
 [[File:KompSiloFensterAussen.jpg|thumb|100px|left|Details of the windows, view from the outside]]
 [[File:KompSiloFensterInnen.jpg|thumb|100px|left|Details of the windows, view from the inside]]
-* Innen eingebaute Drahtgitter als Maßnahme zur Erhöhung der Luftdurchlässigkeit sind unnötig. Sie behindern aber das Zusammensacken des Verrottungsmaterials und wurden deshalb im November 2017 wieder entfernt.
+* The air permeability of the biomass is good enough, even without special means to increase it. The initially built in grids have been removed after a few weeks.
-* Die Umgebungstemperatur spielt eine wesentliche Rolle. Ist sie zu niedrig (< 10°C), verlangsamt sich der Verrottungsprozess sehr stark. Das hängt u.a. auch mit der schlanken Bauweise zusammen, bei der die entstehende Wärme schnell an die Umgebung abgegeben wird.
+* The surrounding temperature is important. The decay slows down below 10°C, which is caused by the slim shape of the silo in this case. The heat is too easily radiated by the large surface.
-* Die Feuchtigkeit muss hoch genug sein, um nicht nur den Kleinlebewesen sondern auch Bakterien optimale Bedingungen zu bieten. Das  Verrottungsmaterial sollte immer tropfnass sein.
+* The moistness must be high enough to support the [[microbes]] optimal. The biomass should be dripping wet.
-* Eine Entnahme der verrotteten Biomasse ist nicht unbedingt erforderlich, denn bei genügend hoher Feuchtigkeit wird das Material nach und nach vollständig in Kohlendioxid, Wasser und sonstige flüssige bzw. gasförmige Stoffe umgesetzt.
+* Removal of the compost is not necessary in any case, because the decay process is continued down to [[water]], dissolved [[minerals]] and [[carbon dioxide]] if the moisture is high enough.
-* Für die Belüftung reicht der im Silo entstehende eigene Konvektionsdruck nicht aus. Deshalb ist ein zusätzlicher Druck bzw. Unterdruck an den Lüftungsanschlüssen notwendig, welcher z.B. bereits durch windbedingte Druckunterschiede an verschiedenen Dachflächen des Wohngebäudes ausreichend gegeben ist.
+* The air ventilation does not work with the own convective pressure in this prototype. This again can be due to the slim shape. Therefore, an additional gentle push is required. Placing the air outlet on an appropriate location of the roof is good enough, letting the wind pressure do the work.
-* Wenn Biomasse von der Thuja oder anderen stark aromatischen Gehölzen eingebracht wird, verlangsamt sich die bakterielle Aktivität und die Temperatur sinkt stark ab. Es bleibt zu untersuchen, ob der Effekt zur Unterbrechung der Heißrotte während der Sommermonate genutzt werden kann.
+* If thuja or other biomass with strong aromatic oils is put in, the microbial activity is impeded and the temperature declines. This effect is subject to further studies. It may be useful for pausing the decay process during the warm summer months.
-==== Umbau nach dem ersten Winter ====
+==== Modifications after the First Trial ====
-Im Juli 2018 wurde der Prototyp umgebaut. Alle Öffnungen wurden durch einen HT-Rohr-Flansch verstärkt und sorgfältig abgedichtet. Ein durchgehendes Kunststoffrohr für die Warmwasserbereitung wurde rechtsseitig eingebaut und die Anschlüsse herausgeführt.
+The prototype was modified in July 2018 to make it ready for the second winter. All ports have been reinforced by a waste water coupler and carefully sealed. An additional pipe has been fed through the silo for water heating. The silo has been placed in a warmer location in a dwelling house, where the surrounding conditions are nearly the same as in the intended use. The air inlet has been corrected to the breather pipe of an existing waste water canal.
-Für den zweiten Winter wurde der Prototyp in einem Wohnhaus aufgestellt, um den Betrieb in einer Umgebung zu testen, die den vorgesehenen Einsatzbedingungen entspricht. Der Zuluftanschluss wurde an das Entlüftungsrohr eines Abwassersystems angeschlossen.
 [[Category:Composting]]