Results of the first year using the DF520 at efm

After finally getting around to doing the heat loss calculations for efm, using the HVAC computer program, it seems like the unit is under rated.

The total heat demand is 383,000 BTUH, based on design conditions to keep the warehouse at 60º and the office at 74º for 24/7. We do turn back the heat during the night and on weekends, but the stoker is able to keep up, with room to spare. This figure agrees with another heat loss calculation, done 5 years ago by a supplier.

Total coal consumed for the first heating season was 9 tons. The warehouse area is 7000 sq. ft, with no insulation, glass walls, and a 30 foot uninsulated, peaked ceiling.

Your numbers are impressive. That is a lot of heat for 9 tons. You should be very happy.

When our coal supplier came the first time and looked around, he said we'd probably use 16 tons, so we are more than happy.

What outside temperature did you use to calculate the heatloss? Did your heatloss program allow for wind and a pickup factor?

stoker-man wrote:After finally getting around to doing the heat loss calculations for efm, using the HVAC computer program, it seems like the unit is under rated.

The total heat demand is 383,000 BTUH, based on design conditions to keep the warehouse at 60º and the office at 74º for 24/7. We do turn back the heat during the night and on weekends, but the stoker is able to keep up, with room to spare. This figure agrees with another heat loss calculation, done 5 years ago by a supplier.

Total coal consumed for the first heating season was 9 tons. The warehouse area is 7000 sq. ft, with no insulation, glass walls, and a 30 foot uninsulated, peaked ceiling.

Any one that knows these units already knew that decades ago Been telling you & others for years that the efm's were underrated. Simply math will tell you that Feed Rate Vs Btu's per lb heat loss / Efficiency

The program uses design outdoor conditions of 88 Summer and 9 Winter for the Allentown, PA area, with a daily range of 22. No place to factor in wind, but alot is already programmed into it that I don't have to manually add. With all the leaking windows and walls and uninsulated volume of space above the floor, the program is probably on the low side.

stoker-man wrote:The program uses design outdoor conditions of 88 Summer and 9 Winter for the Allentown, PA area, with a daily range of 22. No place to factor in wind, but alot is already programmed into it that I don't have to manually add. With all the leaking windows and walls and uninsulated volume of space above the floor, the program is probably on the low side.

Taco has a free heat loss/gain software calculator for download. It's named "Taco HVAC Load Calculator" and is available at:

http://commercial.taco-hvac.com/product ... tegory=370

You need to register with your name and e-mail address to get to the download site. There is also a training video which you can view on-line or download for local viewing.

The load calculator tool is quite useful, but it has a steep learning curve. It's intended for commerical buildings but once you understand the principles of heat loss calculations it's easy to use it for a typical residential home. The video is rather dry and boring but it will give you an idea of the programs capability. While the analysis is not called "Manual J" it's really the same type of calculations. Manual J is copyrighted procedure. The Taco tool uses the same engineering calculations.

Outside weather design conditions are a part of the program or you can enter your own. Makes it straightforward to customize to your unique location.

The residential program alone was about $400. Here is what is said about the design temperature and sizing and below it are all the questions asked about each wall. Windows and doors within that wall are another section. Below is about 10% of the information needed for a whole house.

Researchers suggest that you calculate your “Design Heat Loss” at a Design Temperature. The Design Temperature is chosen to be the temperature that your location will be warmer than, 97 ½ percent of the heating season. The recommended Design Temperatures for hundreds of cities in the USA and Canada are built in to HVAC-Calc. If you were to choose a furnace that exactly matched your heat loss at the design temperature, it would be able to heat your house just fine 97½ % of the time in an average winter. But an average winter means that there are winters colder than average and warmer than average. That is why most contractors would choose a furnace size that is larger than that needed at design conditions by a safety factor. I use a safety factor of 15% to 25%.

Walls: (Each exterior wall, on each floor, must be done individually)
Any windows and doors in a wall must be included with that particular wall. A rough drawing of each wall can be supplied, if easier, showing windows and doors. All measurements, in feet and inches for walls, windows, and doors, must be included for the length, width, or height.

What direction does the wall face?
O North
O Northeast
O Northwest
O East
O East Northeast
O East Southeast
O West
O West Northwest
O West Southwest
O South
O Southeast
O Southwest

O A: Wood frame, with sheathing, siding or brick
Wall cavity
O None
O R-11 3 ½”
O R-13 4”
O R-19 5 ½”
O R-27 7 ½”
O R-30 8 ½”
O R-33 9-10”

Select exterior insulation
O None
O R-1.3 ½” Asphalt board
O R-1.8 ½” Beadboard
O R-2.5 ½” Extruded poly board
O R-2.7 ¾” Beadboard
O R-3.6 1 in. Beadboard
O R-3.8 ¾” Extruded poly board
O R-5.0 1” Extruded poly board
O R-8 Sheathing

O B: Masonry, above grade
Select insulation value
O R-5 1”
O R-11 3 ½”
O R-19 5 ½”

Wall construction – no added insulation
O 8” or 12” block
O 8” block and 4” brick

O C: ICF Insulated concrete form, above grade
Select ASTM R-value
O R-12 to R-14
O R-14 to R-16
O R-16 to R-18
O R-18 to R-20
O R-20 to R-22
O R-22 to R-26
O R-26 to R-30
O R-30 to R-36

O D: SIP Structural Insulated Panels
O 4 ½” panel
O 6 ½” panel

Exterior finish
O Stuco or siding
O Brick
O Split logs on both sides

O E: Logs

Circle the log thickness: 6” 7” 8” 9” 10” 11” 12”

O F: Block or brick, extends to 5’ below grade
Select insulation value
O R-5 1”
O R-11 3 ½”
O R-19 5 ½”

Wall construction – no added insulation
O 8 or 12 inch block

O G: Block or brick, extends over 5’ below grade
Select insulation value
O R-5 1”
O R-11 3 ½”
O R-19 5 ½”

Wall construction – no added insulation
O 8 or 12 inch block

O H: ICF, extends to 5’ below grade
Select ASTM R-value
O R-12 to R-14
O R-14 to R-16
O R-16 to R-18
O R-18 to R-20
O R-20 to R-22
O R-22 to R-26
O R-26 to R-30
O R-30 to R-36

O I: ICF, extends over 5’ below grade
Select ASTM R-value
O R-12 to R-14
O R-14 to R-16
O R-16 to R-18
O R-18 to R-20
O R-20 to R-22
O R-22 to R-26
O R-26 to R-30
O R-30 to R-36

I've been wanting to get a BTU meter, these units monitor two water temperatures, and water volume to calculate how much energy has moved throught the pipes. These are mostly sold to landloards for billing tenants, but should work good to determine the BTU's produced by a boiler.