Comparing two systems in the 2007 BNL report

[Deleted User]

Looking for help interpreting BNL’s 2007 “Performance of Integrated Hydronic Systems” report in regards to an oil boiler purchase. According to the Appendix, it appears that Unit 3 is the Energy Kinetic System 2000 and Unit 5 is the Buderus G125BE (though I’m not 100% sure as the stated AFUE doesn’t match the G125BE specs). These two units compared similarly on estimated yearly fuel savings (Table 4), with the edge to the EK system. I have searched and read older BNL posts on this board, but could not find answers to some questions. I hope the Wall could lend an opinion or two! This is not an attempt to rekindle old EK threads, but rather to pinpoint key features that would assist a HO (or maybe just me! ) when upgrading or replacing an oil boiler.

Q1: The paper noted that the ODR of the “German” boiler was not used, but set manually. There’s a little blurb at the end of Appendix 5 that discusses the efficiency gain in using lower temps, but I couldn’t get a feel for how that plays into the systems efficiencies as described in the paper. What impact would this have on the overall efficiency of the “boiler system”? 0-1 percentage points? 2-5 percentage points? More? Why would the testers not use ODR (too difficult to simulate, perhaps)?

Q2: Both the EK and German boilers were praised on their low system idle loss. If I was looking for other systems, it seems “well insulated” and “cold start” would be two important factors to consider in a boiler. Is this the correct assumption? How does one compare insulation quality among different boilers and mfgs?

Q3: If my assumption of the German boiler is correct (that it is a G125BE), then both boilers have a post purge feature. Is this another important factor to consider in the efficiency equation? Is this easy to install using standard tekmar/Honeywell controls?

Q4: And finally, how important is boiler mass (steel vs CI) and water volume (2.5 gal vs. 8.7 gal) between the EK and German boiler, respectively? From these tests, it doesn’t seem to be a big factor.

Many thanks, JD


BNL paper:
http://www.nora-oilheat.org/site20/uploads/FullReportBrookhavenEfficiencyTest.pdf

Mellow_2

very quick post

q -1 to compare boilers, they made them both cold start boilers.(not the way buderus is designed) The boilers have to be controled the same way to compare.
Q-2 well insulated is a must for a boiler but cold start is not always good for eff. The more temp. change in the boiler the more the boiler runs.
q-3 buderus dose constant circulation with the 2107 control. this keeps the boiler cool most of the time...... Other controls normaly keep the boiler hotter....
Q-4 If you want a system that ramps up in 90 seconds heats the zone and shuts down cold the system 2000 will work......
If you want to maintain a comfort level in a home by circulating warm water through the heaters the buderus is the one (odr cc). The correct installation is very important and I would find the boiler that would work best for the system and the home owners life style.

[Deleted User]

thanks

Mello...Thanks for the reply. Interesting, though, that BNL would test the Buderus in a manner inconsistent w/ its design and/or 'in field' operation. The test might not be a true indicator of how the German boiler might perform in the field.