Paolo Dallai (told by The Paolo’s in Italian & English) - THC Cubo

This is a summary of a presentation during the 3rd International Biomeiler Conference in Leipzig in 2018.
This presentation has been transcribed and summarised by Arie van Ziel, please contact me if you'd like to extend on the text or edit something.

This talk is about a thermocompost system in Reggio Emilia Italy in 2016. It’s about the second rebuild of the same biomeiler.

It is a cubic construction, where one side can be opened for emptying and filling the system.

It’s for heating a large house with a special skirting wall heating system. Similar to the german ‘tempurierung’ system, but only in the plint along the wall and made out of aluminium. It uses about 50°C water. There is also a solar termal hot water system in the house integrated in the heating system.

In the first project they had used manure, but the second build up was ‘vegan-style’.

The box has a double layer where loose straw can be put in from the top as insulation.

The tubes used to be fixed to a carbon steel grid, but it totally corroded. Eventhough it could be reused, it had to be handled with care because of the sharp edges. Probably next time all the steel is gone.

Also the old temperature probes had been corroded completely and broke after only two months, so now he used a stainless steel end piece in combination with a pe, nylon reinforced tube connected.

He used pt-100 sensors.

All tubes are the same as for floor heating and collected into a hydraulic manifold with flow sensors for each of the six circuits which are horizontal in the biomeiler. The manifold is directly at the biomeiler in an insulated box. Each circuit is regulated with an electronic on/off valve and a temperature sensor.

The main tube to the house is insulated with several layers of different insulation. First PUR and glasswool around and a pvc tube around that for protection.

The whole heat exchanger and pup setup was first in the box at the biomeiler, but later he moved everything to the house because it was easier to put internally and combine it with an insulated buffer tank.

The biomeiler is connected to the house as a hot input to the central heating system. Everything is connected with a three-way valve and an normal valve switching at the same time to make sure that there is no hammer-shot effect in the heating system input. It could also be done with an one-way valve, but because of the low pressure in the system this was not possible. There is also a manual valve on a small opening to prevent pressure differences.

In the biomeiler part of the system is glycol, but in the house system is normal water. Because of possible residues in the buffer tank it was needed to put a filter for certainty.

In the first setup there was insulation at the bottom, but this was not replaced in the second build up. Therefor the bottom circuit was only 32°C.

There used to be aeration pipes in the bottom as well, but they were not used again because the air circulation was too high. Also in the higher layers was a smaller aeration system, but while the biomass was sinking down, it was crushing the pipes, so this was not used either.

An automatic watering system with a toilet valve was used to wet the biomeiler during the proces.

In the top there was a dripping pipe for watering the biomeiler. This was first put in in a chaotic way. By putting a ring shaped tube from a T-piece in the end of the watering pipe the watering is more evenly spread.

In the second build up sprayers were used to water the biomeiler during the first days after the buildup.

The structure of the biomeiler is from steel scaffolding poles, with a second layer around it of wooden pallets filled in between with loose straw insulation. As a water protection on the side and the top of the straw he used a breathable but watertight layer, like the ones used in the roofs of houses.

Conclusion see presentation sheets. [will be added soon]