Short Cycling

Tobias_3

I am in the planning stage of a fairly aggressive retrofit on the building enclosure of my house. My goal is to greatly increase the R-value of my building shell. This would mean that the almost new (less than 2 years) oil boiler would be to large for the heating load of my house. The boiler supplies heat and dhw
My question is, if the boiler began to short cycle due to the reduced heat load, how big an issue is it and, if it is an issue, what can be done about it?

I have though that perhaps another, larger, indirect water heater could be added. This unit could act as thermal storage, and would allow the boiler to run longer when called, and the boiler would be called for heat less often. Another thought would be to add a deep layer of sand under a slab-on-grade portion of the home, and run pex tubing into it, and use that mass a thermal storage.

Are these ideas sane, or should I just be considering replacing the unit with an appropriately sized heat source?

clammy

oil fired

if it is oil fired you may be able to down size the noz as for the thermal sorage issue if you don't have enough hot water now check out thermomax domestic tanks and if dhw is not a issue another product called the boiler buddy it is a buffer tank with 4 connection and works as a buffer tank and a hydro seperator and aids in air removal with a simple set point controller to control burner would help increase burner time . make sure you have some one who is familar with oil burners set your burner up some burners when down fires may require a static plate and air adjustment and of course a combustion teating to ensure proper combustion peace and good luck clammy

Unknown

This is why you do envelope before heating systems

you would either mix off of a tank in shell indirect, that's a viable option, or you would add a buffer tank if this is necessary.

A good reset control could utilize the boiler itself as a bit of a buffer as well.

Tobias_2

Hello Rob,

Yes indeed this is why you do envelope before heating, yet here I am. The heating was a necessity at the time, or seemed so. The envelope is an experiment, see what I can reduce my energy use to, and drum up some business armed with some real world digits, since my house is fairly typical of the area, but small enough to be a manageable project. You know, try and create some work.

I'll do a little research on your and clammy's responses, and come back here with some intelligent questions. Thanks for the input.

-Tobias

Larry C_13

Don't use sand as a thermal mass

Another thought would be to add a deep layer of sand under a slab-on-grade portion of the home, and run pex tubing into it, and use that mass a thermal storage.

See other thread about using a sand bed for thermal storage.

Larry C

Unknown

Sorry Tobias, that comment was really intended for others who might read this thread, rather than "rubbing your nose in it". Sorry if it sounded harsher than intended.

Tobias_3

I didn't take it that way at all. No apology necessary. I appreciate the expert feedback I get here.

-Tobias