PELLET STOVES IN CHURCHES
Pellet stoves can be a good alternative to boilers fired by oil or gas in churches, located outside areas with district heating.
There are pellet stove systems that are virtually fully automated but most wood pellet boilers require a certain degree of work handling the pellets, cleaning and inspection. Most of the work takes place during normal working hours, but assistance at other times might be needed.
Requirements for the boiler room and storage
When installing a wood pellet boiler, certain requirements regarding the boiler room and storage must be met (fire codes, etc.). An existing chimney must be checked for suitability before the boiler is installed.
It is recommendable that pellet storage is kept close to the boiler room to facilitate easy loading of pellets. Wood pellet boilers are available on the market that automatically suck the pellets from a silo (which can easily be established in an existing building or container). However, a screw conveyor is usually necessary for loading (which requires a slightly higher silo with a conical bottom and a discharge below). Manual refilling from bags is possible as well, if necessary manpower is available.
Constructing a completely new building for the boiler room and storage can be difficult, because it requires a location close to the church, which must be approved.
Replacing the boiler
When replacing boilers, it is important to fulfil requirements stated in the Ministry of Ecclesiastical Affairs’ Heat Circular. The heat distribution system (radiators or calorifier) must be well dimensioned and in good condition. If the heat distribution system does not meet the requirements, a new boiler alone will not be a good solution. It will require that the entire heating installation is renovated or replaced.
If the entire heating system is replaced, it is worth considering switching to electric heat instead, especially if it is a periodically heated church that is only in use 1-2 times a week.
Joint heating plant?
If the church, vicarage and possibly the parish community centre and cemetery facilities are close to each other, establishing a common central heating station for all the buildings might be worth considering. This can work well if the heating system is built correctly. Installing two wood pellet stoves as a cascade system (typically with a larger and a smaller boiler) is recommended. The advantage of this solution rather than one big boiler is that loss of energy is minimized considerably.
During winter, there will be a very high heat demand when heating the church. The total output of two wood pellet boilers must be dimensioned accordingly. During summer, heat demand in turn will be very small (for hot utility water and possibly tiled floors with underfloor heating). The little boiler will cover the summer heat demand and should be dimensioned so that there is a sensible operation also in the summer.
The price of pellets varies considerably, as does the quality. Heating with wood pellets is generally cheap. The prise is typically 40 to 45 øre per kWh heat.
Investment costs vary widely. There are big price differences on individual brands, including different functions. Some are almost fully automated, while others require more manual effort. Extra costs for boiler room, chimney and storage room also varies enormously. It is recommended that more than one specified tender is ordered. If major structural changes are required, an architect must usually be involved.
Feldballe Church in Syddjurs Provsti is heated with wood pellets. They have established a common heating plant for the church, vicarage and other heated buildings.The vicarage is a listed building and the stove is installed in one (previously unused) part of the building, which has been converted into boiler room and storage room.
In Saksild near Odder, the church wanted a similar solution. However, there was not a suitable building, which could be used as boiler room. Permission was not granted for the construction of a new building for the boiler room, because it would ruin the view from the church.
Read more (in Danish):
Boiler list: http://www.teknologisk.dk/kedelliste/35412
Order on Particle Air Pollution: https://www.retsinformation.dk/Forms/R0710.aspx?id=175857
Chimney Sweep Guild: http://www.skorstensfejerlauget.dk/vaerd_at_vide.html
Fire safety instructions: http://www.dbi-net.dk/btv-32-biobraendselsfyrede-centralvarmekedler
AT-guidance, Technical equipment – B.4.8
EU requirements in force from 1 January 2020: http://eur-lex.europa.eu/legal-content/DA/TXT/PDF/?uri=CELEX:32015R1187&from=EN