Hot Box

[mpilchuk]

I built this box that heats water for my heat exchanger. Noah (np0x) had built one with an old cooler. We talked about a more elegant way of doing one. We toyed with copper pipe but in the end I just wanted to get one built so I could use my system.

I'd love to hear from other people about how they have done theirs.

This is an old six pack cooler.

[ECC]

That looks pretty good to me. I'm interested in hearing the 'more elegant' way that you've been discussing, because that looks elegant to me

Just so others know, these guys using a counterflow chiller for the actual heat exchanger. Recirculating the mash through one end, and then circulating water heated by the hot box through the other end.

Another option I've been kicking around is to use a RIMS copper pipe heat chamber/element for the hot side. I know missing_link is putting together and offering RIMS heat exchangers that look very nice.

[bsfixit]

Here is what I use currently. Its a SS 8 gallon pot. My first boiling kettle. I put a SS immersion chiller inside with about 2.5 gallons of water, for mash temp control, as a HERMS. The SS chiller works well , But I have a copper coil I was thinking of replacing it with, much more thermally conductive. Then I just heat water in it for the sparge.
I too am looking at missing_link's rims heater. He sent me some pictures of it. It looks nice.
Brett

[np0x]

Getting a bit off topic here, but staying on the HERMS theme...In my design efforts I came to the conclusion that I did not want a big volume of water for my herms tank, big is a relative term but it all plays into over shooting temps. The smaller the water in the herms tank the less potential for overshooting the temp when you finally reach your target. My struggle was always finding the smallest vessel that I could use that was big enough for the heating elements and had surfaces I could mount the inlets for my heat exchanger on. My herms system probably holds about 2 gallons of water as well between all the plumbing, the cfc and the tank. It seems to not have any issues, it is 16 lbs of water compared to the ~80lbs of typical mass of grain and water in my mash tun.

Quite a few of the herms designs I have seen use the HLT as the "hot box" but I felt that a vessle that large would be hard to control and keep my mash temps from oscillating wildly.

[bsfixit]

So, you dont batch sparge with a hot box? do you drain the first runnings, add the sparge water... bring it all back up to mash out temp then drain again?

[ECC]

I totally agree, smaller is better (in this case).

Seems to me the optimal setup would be CFC heat exchanger, with RIMS heater on the hot side. Its not actually RIMS anymore, since the CFC makes it a HERMS system. But the RIMS style heater would be much less volume than the cooler based hot box.

I think this would be optimal in the sense of heating responsiveness, and keeping with the HERMs theme.. But the cooler based 'hot box' method has some definite advantages. Probably cheaper, can fit multiple elements easily, insulated.

[ECC]

So, you dont batch sparge with a hot box? do you drain the first runnings, add the sparge water... bring it all back up to mash out temp then drain again?

Systems with an external heat exchanger (hot box) usually have a totally separate HLT, so sparging occurs as usual.

[np0x]

In my system I get my sparge water "close" and pump the sparge water through my heat exchanger as well by changing a couple of valves...so my cfc and BCS give me EXACT 168F sparge water as well as controlling my mash temps.

One of the primary advantages of the cooler over a rims style heat exchanger is priming and knowing how full it is, a non-cooler based system would effectively be a closed loop and I grew increasingly concerned with the expansion of water as it heated and dealing with purging air or adding water to the heat exchanger side in a non-cooler style construction.

beyond that I think the amount of water you should use is the minimum amount to fully submerge your elements and keep them submerged when the system is fully primed. The cooler lets me just use a hose and adjust as necessary.

[missing_link]

I had initially used a 1 gallon cooler as my heat exchanger. I attached 2 disconnects to the lid, heating element came through the bottom. The pump would force water into the cooler, the heated water was forced out the other hole in the lid.

While it worked it wasn't the best solution because I was doing RIMS and having an extra gallon of water not in contact with the grain was not ideal. Plus I had to find a way to mount the cooler safely.

I recirc the wort through the heat exchanger and I am constantly amazing people with the accuracy of the system. I measure temps at the in and out points of the mash tun and they are almost always within .5 degrees of each other.

Linc

[np0x]

Sounds like a well insulated mash tun as well, what are you using? (keggle myself here)