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Sizz · 07-27-2009, 02:12 PM

Quote:

Originally Posted by samc

I am working on mine as well. I am going to feed the stainless pipe heater via gravity and have the March pump on the exit of said pipe heater.

One of us has it wrong I think, not sure who? Does it matter?

You are a lot more organized than me. I have no clue how much I have sunk into this already.

My thinking was that if you get a stuck mash, the pump could potentinally drain the heater and burn out the element.

Sawdustguy · 07-27-2009, 04:59 PM

Quote:

Originally Posted by Sizz

I don't think I'll have scorching issues. I intentionally made the pipe the smallest diameter possible to allow the fastest flow over the element.

I wouldn't use a high density element in my RIMS heater but I hope it works out for you. You can only flow so fast when re-circulating the mash depending on how fast the liquid filters through the grain bed on top of your false bottom. With the narrow tube you will have a smaller amount of mash in contact with an element that has 150+ Watts/Sq Inch. If you used a low density element it would be half of that Power/Sq Inch and if you used an ultra low density element it would be a quarter of the Power/Sq Inch.

leboeuf · 07-27-2009, 05:06 PM

The scorching issue will depend on how you control your element. They don't heat up instantaneously and if your control system (controller/ssr) can handle it, a small pulse width will probably keep things in line.

If you're really worried I think you could pulse your setup with water and determine your differential temp change. Then you can set your pulse width accordingly.

I didn't look that close to see what kind of heat sink you have on your SSR, but you'd probably be fine if you add a fan. Just be aware that the smaller your PW the more dynamic power you'll be burning.

Tom

EDIT: Just saw your sparge plans. You'll probably need to have a separate control routine to keep your sparge water at temp

**Bobby_M** · 07-27-2009, 07:09 PM

If this works, it will be the ideal electric based setup for sure. No HLT and perfect temp control of the mash. I agree that the control will have to be different for mash maintain and sparge. During sparge, you'll want to use 100% output to reach the desired sparge temp upon output of the hex. Yes, you'll have to run it slow as hell, but that's fly sparging anyway.

During mash maintain, wouldn't running the element at 50% cycle be the same as a low density? Are the warnings about scorching based on experience or guesses?

lamarguy · 07-27-2009, 07:19 PM

Quote:

Originally Posted by Bobby_M

During mash maintain, wouldn't running the element at 50% cycle be the same as a low density?

Theoretically, you would have to operate the heating element at 25% power to achieve an ultra-low density. But, you may be able to get away with something between 25% - 50% power.

The real issue are the different PID settings (gain, etc.) necessary to achieve both mash and sparge water temperature differentials. Operating the mash with the sparge PID settings will absolutely result in excessive wort caramelization.

Tankless water heaters have a large surface area to water ratio to achieve high temperature differentials. You're better off buying a commercial version than attempting to build one yourself. Don't forget, you'll need to heat the strike water too...

**Bobby_M** · 07-27-2009, 07:27 PM

Well, tankless heaters also have to accommodate 10x higher flow rate than a sparge would so the power requirement is spiked.

There is theoretically no difference in strike heating times between this method and having an element directly installed into an HLT. In the instant system, the water is flowed in slowly at temp. In a dedicated HLT, cold water blasts in and then you wait for the heat. Either way, you wait.

Even if you built two RIMS style HEX tubes, each designed for their purpose, it's deleting one vessel. It would also allow for a fly sparge on a single tier with only one pump.

Compare the price difference between building a RIMS tube and building an E-HLT. Maybe break even?

All I'm saying is that this isn't one of those ideas that should be discouraged right away. If it fails, all the parts can be reused in the more traditional HLT.

leboeuf · 07-27-2009, 07:44 PM

Yea I think it's an awesome idea!

You'll really just need a somewhat robust pid and good temp control on your ssr. Once upon a time I set something akin to this up for the fab I worked at while in college. I remember using a pid that had 4 setups that you could cycle through with the push of a button. I wish I remembered what brand it was..... it was blue lol....

slimer · 07-27-2009, 07:54 PM

The BCS allows for finite control over the SSR, but IIRC the duty cycle is at 1 second intervals. If you want 25% power, it cycles 1 sec on 3 sec off. In my head, that would create some major pulsing.

Sawdustguy · 07-27-2009, 08:43 PM

Quote:

Originally Posted by Bobby_M

If this works, it will be the ideal electric based setup for sure. No HLT and perfect temp control of the mash. I agree that the control will have to be different for mash maintain and sparge. During sparge, you'll want to use 100% output to reach the desired sparge temp upon output of the hex. Yes, you'll have to run it slow as hell, but that's fly sparging anyway.

During mash maintain, wouldn't running the element at 50% cycle be the same as a low density? Are the warnings about scorching based on experience or guesses?

Actually I give the OP an A+ for the concept. I have never scortched my mash because my RIMS uses a 1500 watt low density element. Call it gut feel, but I just can't invision how the mash wouldn't scortch going by a 5500watt high density element. I don't think the flow rate will be as great as he thinks. Don't misread me. I hope I am wrong. Just because Just because I choose to do it differently, doesn't mean it won't work. I have no proof it won't work. It will certainly be an interesting experiment. If he is successful it will be good news for those who are looking to build a simpler system.

leboeuf · 07-27-2009, 09:15 PM

Quote:

Originally Posted by slimer

The BCS allows for finite control over the SSR, but IIRC the duty cycle is at 1 second intervals. If you want 25% power, it cycles 1 sec on 3 sec off. In my head, that would create some major pulsing.

Most run of the mill PID's can do a 2 second period. I'm interested to see if ~200ms will be long enough to cause enough temp variation to scorch. I looked around for response curves for hot water heater elements but found nothing lol