Studio Pellet Stove
Over winter break, we finished off our studio pellet stove installation. Because of the pitch of our roof, we needed to extend the exhaust piping seven feet above the roof, so we installed the pipe with a roof mounting kit to stabilize the pipe.
Inside, the pellet stove was centered on the north wall with the heat fans oriented to the south. It is best to position a heat source in a room so that the heat output is facing the area of greatest heat-loss potential (large south wall windows.
Regulations require a fire barrier behind the stove. Manufacturers and distributors do sell fancy “hearth plates” but you can also purchase Hardie Board (basically a thin sheet of concrete) from a hardware store (about $5 for a 3’X5′ sheet) and paint over it with black stove paint to save money.
The wood pellets are loaded into the top of the stove into the “hopper” which then feeds the pellets onto the “burn plate” at a steady rate. If you are considering a pellet stove to heat your space, be sure to inquire about the hopper capacity. Bigger hoppers will of course require fewer refills (ours holds 40 lbs).
We have some unique heating needs at the FLAT. We don’t use the studio space enough to leave the stove running constantly, but we do have several evening events throughout the week which require the space to be warm.
Keep in mind the floor of the studio space is a thermal mass consisting of 3″ of concrete poured over 2″ of rigid board insulation:
- The rigid board insulation was set on top of the existing foundation, then 1mm plastic was set on top of that and the concrete was poured over the plastic. The plastic is necessary to keep concrete moisture from seeping into the foam and filling the pore space which gives it an the insulating quality.
Since we do not leave the pellet stove on, when we want to heat up the space for an event, we are not just heating the room, we are also heating the thermal mass in the floor. In addition, every substance has the ability to absorb heat and is therefore also a thermal mass. Some materials are better than others at absorbing and giving off the heat which gives them different R-values (R stands for “resistance” to heat movement). So we must heat up the wooden walls, the chairs, curtains, cob on the west wall, and the ceiling in addition to heating up the room and the concrete floor. At this point, we are unsure exactly how many pellets and how much energy are required to heat up the space and keep wit warm for different events. Should we leave the stove on a low setting if there are evening events two days in a row to avoid having to heat up the space twice? Should we try to always maintain a constant elevated ambient temperature so we don’t have to use as much energy to heat up the space each time? To answer these questions, we have begun a monitoring program:
With a Kill-O-Watt monitor in the outlet, we will record the amount of energy used during different trials. With the temperature log (held by hand in photo) which can be plugged into a USB port to quickly create temperature graphs like the ones here we will be able to track heating and cooling rates.
With a focus on energy use, our first trial will look at energy and pellet use when the pellet stove is running constantly on a low setting. Then we will track energy and pellet use for different thermostat settings which turn the stove on and off to maintain a constant temperature. Finally we will track energy and pellet use when we use the preheating method and allow the space to cool down between events.
Once we have completed the first round of monitoring, we will test the impacts of various amounts of thermal mass on heating and cooling rates by conducting trials with zero to three 50 gallon barrels, painted black, and filled with water.
Once we conduct these tests we will be able to make better decisions about how and when to heat the studio space in order to meet various needs.