Step Mashing with 2200W RIMS?

[Jackanapes]

Is it possible to efficiently do a step mash with a 2200W RIMS setup? This question has more to do with what kind of controller I should get/build. If efficient step mashing is possible, I would probably go ahead with a controller capable of handling 20 amps. Otherwise, I might just go with 1600W element and something cheaper like an Inkbird IPB-16 since I'm not sure when I'll be able to make the jump to 240V (which would definitely be years off).

 

[augiedoggy]

Yes I do it with an 36" long 1800w cartridge heater... I get between 2.5-3 degrees rise in temp out of it per minute. I brew 10 gallon batches. The key is the length of the heating element and rims is longer which provides longer heating contact on each pass which = more efficient heat transfer compared to most rims setups.

 

[Vale71]

Yes I do it with an 36" long 1800w cartridge heater... I get between 2.5-3 degrees rise in temp out of it per minute. I brew 10 gallon batches. The key is the length of the heating element and rims is longer which provides longer heating contact on each pass which = more efficient heat transfer compared to most rims setups.

I'm sorry but I really don't understand your point. Since the heating element is inside the liquid all heat has to be transferred from the element to the heater and cannot just disappear into thin air. The efficiency can then only come from the heat losses that the system will suffer after the heat has been transferred to the wort. A longer element will in general have a larger surface than a shorter one and so suffer from higher losses, provided the elements are of the same diamater and material. Why do you think that the longer element would be more efficient despite it actually suffering from greater heat loss?

 

[augiedoggy]

I'm sorry but I really don't understand your point. Since the heating element is inside the liquid all heat has to be transferred from the element to the heater and cannot just disappear into thin air. The efficiency can then only come from the heat losses that the system will suffer after the heat has been transferred to the wort. A longer element will in general have a larger surface than a shorter one and so suffer from higher losses, provided the elements are of the same diamater and material. Why do you think that the longer element would be more efficient despite it actually suffering from greater heat loss?

I'll share Why I believe this.

In many rims systems you have liquid passing through a large 38mm opening with a 12-14" long element .. as the liquid passes through at a faster rate of say 3gpm not all the liquid comes in contact with the element some does and gets heated higher than set temp and has to mix with the liquid that doesn actually come in contact with the element and that has to take place before the liquid sees the temp probe on its way out. I made 4 different rims setups experimenting with different elements and sizes as well as wattages. before using this 1800w 36" long 5/8" diameter element I had tried a 1/2" diameter 24" long 2000w element which did not perform as well as the longer less powerful element. I believe that is due to a few factors. one the elements larger diameter does a better job of ensuring more wort sees direct contact with the surface. 2 the longer element also does this as well as ensuring better equalization of temps before it sees the probe at the far end of the rims. also I recirculate slower. this ensures the element also has longer more even contact time and theres less chance of channeling.
It does work well for me and I do average 91% brewhouse efficiency with this.

At the brewpub I have a slightly less efficient setup. the elements are each 28" long and 2200w each, the rims is a giant u shape mounted horizonatlly. the elements are only 1/2" diameter and in a 1.5" tc spool steup. I have to reciculate faster as 5gpm due to the huge time delay with the 3bbl mash. I see between 5-7 degrees rise at 5gpmvs the temp going into the rims vs coming out. if I slow the flow I get loacalized boiling once it drops below about 3.5gpm. I can see this in the sight glass and this is bad since it meand denatured enzymes happening in the rims. I also will get a slimy protien film on the elements if I attempt to raise the temp more than a few degrees at a flow rate below 3.5 or so.. My rims element at home stays completely clean because the lower watt density is preventing this cooking action on the element surface. its works with the advantages of a herm but with the speed and control of a rims this way. Its also important to point out I can recirc at only 1.5-1.8 gpm on my flow meter at home and the element still stays totally clean.

the way I see it its more like the situation in a radiator or heat exchanger like a plate chiller.. you can get better performance with more plate or just longer plates vs just colder water going in.. (also why a longer 20plate duda plate chiller outperforms a shorter 40 plate blichmann therminator btw). and on a radiator if the flow from the water pump is too high you actually start to loose cooling capability. (or heat absorbtion depending on how you see it) Now im not an engineer in this field so im sure thier are things im missing or dont quite understand but I can say Ive formed my opinion based on my experiments and experience.