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Energy generation from welfare friendly straw systems for pigs.


The Pig Heat and Straw System is a system that extracts heat from straw manure to reduce gaseous emissions and to reduce the use of fossil energy on pig farms. The heat is used for heating farrowing rooms, rooms for weaned piglets and the farmers' house. Pilot Pig Heat and Straw systems have been implemented in a house for fattening pigs in Poland and in a house for sows in The Netherlands. Results on energy flows and emissions were monitored. From these measurements the following could be concluded: - From the straw/manure bed 50 70 W/m2 of energy could be extracted in Poland. In The Netherlands this was only 10 W/m2. The main reason for the low yield in The Netherlands was the too thin layer of straw/manure, approx. 20 cm, while it should be > 40cm. - From the roof approx. 50 W/m2 of solar energy was extracted during the summer period in The Netherlands. This was an efficiency of approx. 30%. In Poland efficiency was reached of 40%. The efficiency mainly depends on the temperature of the ingoing water into the solar roof. - Cooling the straw/manure bed reduced ammonia and methane emissions. - For the Polish situation the Pig heat and straw system is profitable. The system is highly recommended for farms situated in places where are difficulties with supplying fossil fuels and strong restrictions regarding the environmental protection. In The Netherlands the system as operated at the pilot plant was not profitable, but major improvements could be made, especially with respect to heat extraction from the straw/manure bed. Furthermore, costs of the system could and should be reduced. Equipment for heat extraction from straw / manure bed in animal’s building will be delivered and installed by SME’s in Poland, The Netherlands and Germany. Costs of the reduction of ammonia and greenhouse gases, what is obligatory for each European country, will be repaid in the form of savings of the costs of fossil fuels. Other energy sources heat from energy roof will encourage farmers to modernise their farms. The R&R Company has patented the idea of the low cost heat exchanging system. The main objective of R&R is to extend their market for the heat exchanging plates from slurry systems to straw systems in animal production and to extend the national market to the international market. The extension to straw systems will make the company less vulnerable in future; when straw systems will be introduced to a larger extend in pig production in The Netherlands, Poland, Germany and other countries within the EU. At the moment the different SME partners in the project are only working for the national markets. This project gave them a start to the international market. The Sanit, Ekoenergia and Hydrotech Companies still have a high potential to extend their market in Poland. The co-operation with R&R Systems helped them to extend their market in Poland on cooling and heating systems in pig production. Bigatec profited from the knowledge gathered within the project and from being involved in the development of an integrated housing / manure treatment system. The results of this project show that the system is especially of interest now for farmers in Poland with difficult access to energy and electricity sources. However, also in The Netherlands and Germany the Pig heat and straw system can be profitable for certain pig farms. The heat recovery system is especially of interest for combined sows and fatteners farms and for sow farms, because the farrowing rooms and the rooms for weaned piglets have the highest heat demand on pig farms. Fattening pigs and pregnant and dry sows on deep straw can deliver the necessary heat. We assume that in 2010 30% of the combined pig farms with more than 50 sows in 1999 and 30% of the sow farms with more than 100 sows will use a deep straw system. Of those farms it is expected that 50% will use the heat recovery systems.