HERMS circulation question

[tinoespinosa69]

Hello
I have a general question related to the use of the HERMS system.
It happened to me while brewing small batches (3 gal) in my 10gal Spike HT with HERMS using less than 7 gal inside the kettle that part of the HERMS coil is not submerged and then the temp setpoint for the recirculation takes longer to be achieved.
I am recirculating the wort entering the lower point on the HERMS and flowing up to the top. Of course, the heat exchange process will be ONLY on the coil that is in contact with hot water, leaving the rest of the coil without further heat transfer and of course increasing time to heat the wort.
I was thinking to invert the connection point, entering the coil using the top port and flowing down to the lower one. with this, I could guarantee the wort will be exiting the HLT with a higher temperature and maybe could reduce the time to get the Temp.
I know the other option will be to fill the tank and cover all the coil with hot water (it is what I did) but to be honest I do believe is not an efficient alternative as I will be heating water I won't need for brewing. (maybe later for CIP)
What do you think about this?
I am thinking to use an alternative RIMS system for small batches.

 

[Vale71]

It'll hardly make any difference. The part of the coil that is exposed still exchanges heat but in the other (i.e. cooling instead of heating) direction, actually causing heat loss. This will happen regardless of where the wort is entering the coil from. There might be a small advantage as it will have a somewhat lower temperature in the exposed part so that it might be worth a try but it will most likely still be higly inefficient. I'm afraid the only real solution with this type of system is to heat up more water than you actually need to ensure full submersion of the coil.

 

[Bobby_M]

Right, just add more water.

 

[tinoespinosa69]

@Vale71 I agree with you, I will lose heat having in mind I will have a convection zone on the not immersed coil. It will dissipate the heat gain in this section after being heated on the immerse zone.
My way of thinking was to have a reverse flow with wort a lower temp entering the not immersed zone flowing to the high temp side. But honestly, the residence time will be low, and to increase the heat transfer (and efficiency of the Heat exchange) will have to reduce the flow on the coil. Another factor affecting my system is that I am currently using an Induction cooktop, so not all the heat is 100% transferred to the water. I will change to an electric heater in some months.

For small batches, I certainly will prefer a more efficient system, so I will pull the trigger with the RIMS or will go with a BIAB type system ( SPIKE SOLO, I am waiting for your small batch system ). For >5gal batches, I will use HERMS with a fully immersed coil.

Thanks for your input on this subject

 

[tinoespinosa69]

Right, just add more water.

Hey Bobby, you are supposed to be on Vacation, so please enjoy your free time..... Cheers

 

[Bobby_M]

This is me enjoying. My feet are in the sand right now.

 

[tinoespinosa69]

Right, just add more water.

YES, no other option. For >5 gal batch this is what I will do and will use the remaining water for CIP. For the smaller batch, I will use your RIMS system (when available)

 

[Deadalus]

For a six gallon batch in my HERMS system, I use about 4 gallons out of the HLT to clean my MT after sparging. If there is anything left in the HLT I toss that that into the BK but generally need to add more simply to get it up to temperature to add PBW (DIY) which I then pump through the HERMS coil and plate chiller to clean. I like to have enough water in the MT to cover up to the level the mash was but I didn't generally fill the BK up as high as the wort was to start with.

You say it's 7 gallons to cover your coils? Minus your sparge water you feel like that's too much water to clean both your BK and MT?

 

[tinoespinosa69]

@Deadalus Yes, it's about 7 gallons to cover the coils. I did not say it is too much, and I could use it for CIP. Of course, this is using the system I built for 5-7 gallons batch.
But for a 2-3 gallon batch, it seems to be a waste of water and will go with the RIMS options. So, I will have a dual RIMS-HERMS system.

Thank you for your comments

 

[Deadalus]

If you really want to have the dual RIMS-HERMS system it's your hobby and if it makes you happy go for it. I am just wondering about claiming it is more "efficient" in regard to the amount of water. My question was, do you think that 7 gallons minus your sparge water is too much water to clean up after a 3 gallon batch? I'm looking at a couple of my recipes and for my usual 6 gallon batches I'm needing to sparge with 5 gallons of water (usually a little more). Roughly speaking you are using about 2.5 gallons? That leaves 4.5 gallons of water at ~170. I would think you could use all that for cleaning. I think the recommended temperature for PBW is 140F? So basically you are only raising 4.5 gallons about 30F. I'm just wondering is that really saving something significant, particularly vs the cost of the new parts. Also, I am not sure of your Rims alternative, but if you are using the same vessels, you are saying that you would use all the excess 7 gallons for cleanup of a five gallon batch, a 3 gallon batch is only a little lower in the vessels level-wise.

 

[tinoespinosa69]

I do not want to have a thesis or Ph.D. dissertation on this subject, as you mentioned, this is our hobby and I raised the question just to know best practices from all the experts like yourself.
I have not problem using the full volume of heated water for small batches. As you mentioned, I could use the remaining water ( already heated to 150-170 F) for cleaning after the sparge. Your calculations are good. And I never said I will have 7 gallons for cleaning. What I mentioned is that I am required to have 7 gallons of heated water on the HLT to have the coil totally immersed for a good HERM process.
What I mentioned with being "more Efficient" is the use of energy on a RIMS system. There is no extra water to heat because the worth is heated directly on the RIMS. Sure this could bring some other concerns as scorching if the temp is not properly controlled.
Of course, I will need the sparge water, but I could have a lower water amount readily available and heated on the HLT without using the HERM for the mash

Again, impressions are personal, facts are real evidence. I am only asking for alternatives or ideas, no discussing facts.

Regards

 

[day_trippr]

fwiw, my 50' 1/2" hex requires just over 10 gallons to fully cover in a 20g hlt. As I heat my strike water separately in my bk and do ten gallon batches I typically use all but two gallons of the hlt volume for sparging, so I'm paying to heat two gallons of water to ~154°F. A small price for consistent performance...

Cheers!

 

[Deadalus]

I never said you have 7 gallons for cleaning either. You will have 7 gallons heated for the coil minus the number of gallons of sparge water you need. This difference ~4.5 gallons is the difference between the RIMS and HERMS. You have to heat the sparge water no matter what. That volume is mostly irrelevant it has to be heated up whether you use the RIMS or HERMS. If you are going to use the water up cleaning, it seems the only efficiency you are getting in regard to water is that you save the energy to raise about 4.5 gallons of water to 30F (which seems small). This seemed to be what you were basing your decision on to get the small batch Rims setup, which was at post #4. My IMPRESSION is that you really want the RIMS and are only nominally interested in the pros in cons.

A home water heater heats water that is anywhere from about 50 to 80F to usually a minimum of 125F. That's a difference of ~45-75F change much more than the HERMs water. If you cut your brew day shower short by a minute or two you'd save the same amount of energy. Cut the water off while you shampoo you'll be saving yourself the cost of the RIMS!

I'm not an expert though. I do have an EHERMS system but I'm not familiar with using RIMS to point out any efficiencies there besides the water part, possibly time for instance. I would say with the BIAB that the water calculations are different as far as I know and I think that is because pot size impacts whether optimal amounts of water can be used. Maybe a small batch in your pot might not be affected by that so you might get some input there. Just be clear what types of efficiencies/considerations are important most.