Straw Heating - Best Decision of Farm in Prasice, Slovakia
The Only Straw Heating Facility in Slovakia
The decision to build a waste straw fired facility at this farm was made during the year of 1993. It was the result of consultation with AGROZET ZVOLEN which was involved in technical support for agro-business and one Czech company dealing with imports of agricultural technologies. The facility was proposed to be the first one in the former Czechoslovakia.
The decision to use straw as the fuel was not driven by environmental or financial reasons. There were no environmental problems with straw burned on the fields because it was almost completely used by agricultural farms or was simply left on fields for rottening. Even the energy prices for heat were artificial low and agricultural farms received substantial support from the government. At this time, there were no real incentives to use this material just to substitute the oil or natural gas on an economical basis. Nevertheless, the decision to build this facility seems to be now the best one, which PPD Prasice has ever done.
Straw-fired boiler installation
The boiler has chamber roof with a 2-stage combustion air supply system. Secondary air is pre-heated before being released into the combustion chamber to mix with the burning volatile gases, enabling the achievement of high temperatures, to give clean and complete combustion. (Low temperature combustion produces smoke, tar and excessive fuel consumption.). The high temperature exhaust gases pass through a multi-tube heat exchanger, transferring heat to the water before exhausting to the chimney at low temperature. No useful heat is lost unnecessarily to the chimney. The entire combustion process is thermostatically controlled and straw is only burned when required.
The boiler produces only heat. Heat is used on site for heating large workshop building (12 m x 80 m), 4 apartments recently used as offices and for warm water preparation. All heated areas are connected to the boiler by good isolated pipeline. The temperature is set automatically and is regularly checked by the operator.
Simple Operation & Maintenance
Until now, local staff performs the necessary maintenance. The system has worked well with no major problems yet and the owner is more than satisfied. Even the necessary work related to manipulation with straw is considered as normal and there is no intention to change this for automatic operation. Straw is stored in a separate sheltered storehouse close to the boiler.
Smoke Under Control
The owner did not estimate the total savings until yet but the investment costs have long been paid off. According to recent price of natural gas and resulted heating costs, the payback time of such a facility would be 3 or 4 years. Annual heat savings are around 150,000 Sk (3,800 EUR).
There is only small amount of ash from burning the straw and it is all
used as fertilizer on fields. Moreover, savings are achieved due to cutting
cost of ploughing-in of surplus straw.
Why No More Plants?