understanding boiler chart
understanding boiler chart
(OP)
Hi there,
I am designing a basic perimeter fin tube system for an office. I am using two condensing boilers. I haven't done this type of system before and am not really understanding how to read the boiler charts. one of the boiler charts is
"Size of boiler vs Temp Rise and Flow" for the Water Flow Data, and the other chart is "Size of boiler vs Req Water Temp Rise and GPH Delivered" for Recovery Data. I am having a hard time grasping the meanings of these charts and how to use them to size my fin/tube. Any help you can give is greatly appreciated as soon as possible. Thanks!
I am designing a basic perimeter fin tube system for an office. I am using two condensing boilers. I haven't done this type of system before and am not really understanding how to read the boiler charts. one of the boiler charts is
"Size of boiler vs Temp Rise and Flow" for the Water Flow Data, and the other chart is "Size of boiler vs Req Water Temp Rise and GPH Delivered" for Recovery Data. I am having a hard time grasping the meanings of these charts and how to use them to size my fin/tube. Any help you can give is greatly appreciated as soon as possible. Thanks!





RE: understanding boiler chart
Don't typically see fin-tube combined with condensing boilers. Fin-tube needs a typically higher mean temp to convect, it can be done, but not a typical installation.
Backing up, the first thing you need to do to pick boilers is determine the heat load of the building. Chose a system delta T which will drive the flowrate.
RE: understanding boiler chart
RE: understanding boiler chart
Most systems are designed for 85 - 95°C (185 - 200°F) water
The flow rate should be sufficient to keep this temperature change within acceptable limits The higher the flow rate, the lower this change. This change should normally be 10 - 14°C (18 - 25°F) for
space heating, go here to calculate:
http://wea-inc.com/
RE: understanding boiler chart
RE: understanding boiler chart
RE: understanding boiler chart
Below is the condensing boiler, LAARS Rheos+
http://ww
The total load on the building is 2100mbh (2.1million btuh). Each workstation (per the client) has 500W of heat output and it is mostly open office...i guess they all have high power computers with 42" LCD monitors on their desks.
The project options were presented to the client before I joined the team, and the decision was to use purely perimeter radiation for heating and indoor air-cooled DX with VAV for distribution. I'm sure you can imagine the size of the louvers I have on the walls of this thing... For the VAV system I will have hot water coils just to temper the air when necessary.
Brief summary...50,000 sq ft office space, 2 floors. tall ceilings and lots of glass. Even the boiler rep suggested we use non-condensing boilers instead for this application, and I agree, however I also recently discovered they want to use condensing boilers for LEED.
DrRTU, I will try your method. I think condensing boilers will be effective if I can run them with a 40degree dT. At the moment I am using two boilers, two B&G pumps, and one expansion tank.
Thanks again guys, I appreciate all the help. Hopefully I can contribute something in the near future to help others.
Andy
RE: understanding boiler chart
The water flow data for the hot water heater tank is based on water quality since such heater is indirectly heated by the boiler operating in a closed loop system whereas the hot water tank operate in an open loop configuration.
Obviously the Rheos boiler has varying firing rates but the sizing data table will show the max. and min. firing rates.
Go on line as Rheos has manuals publicly available from which I was able to deduce the info in the first paragraph.
RE: understanding boiler chart
RE: understanding boiler chart
RE: understanding boiler chart