Solar HERMS setup

**Acidjazz54** · 08-07-2009, 05:25 PM

Hey all. I'd like to get some ideas as to how to go about doing this and whether or not you all think it is a good idea.

In Sept I've gotten the ok from SWMBO that I can build a shed/brew house. The roof of this shed is going to face South so my thought was to put a solar hot water heater on the roof and hook it up to a HERMS rig.

My main concerns are controlling the temp of the heat exchanger and then using that to control the temp of the mash, also I would like to be able to use the heat exchanger to pre-heat the strike water, etc. Any thoughts or suggestions would be great.

donshizzles · 08-07-2009, 07:18 PM

I think its an awesome idea although its going to increase your build quite a bit placing solar panels on the roof of the bewshed. No idea what a solar system would cost.

**Acidjazz54** · 08-07-2009, 08:34 PM

I don't know if I'm going to do Solar PV as well or just Solar Hot Water. There are plenty of places (instructables included) that show how to make Solar Hot Water for fairly cheap (< $100).

I apologize also because I guess this wouldn't be an actual HERMS maybe more just using Solar Hot Water to help heat my HLT.

I just thought of a concern though, my plan was to use a closed loop between the Solar Hot water box on the roof and the Heat Exchanger in the HLT. What happens when all of the water in the re-circ loop reaches temperature? Does it just keep circulating or should there be a blow off? Anyone ever install Solar Hot Water at their house?

**CodeRage** · 08-07-2009, 08:48 PM

I would think of setting up a parabolic reflector heating up some kind of circulating liquid medium stored in a tank and then use a heat exchanger to heat up your mash water. A bit complex but I don't think you'll be able to hit 170 easily with a black box. For temperature control I think some sort of heat exchanger would be required. Then again, I really don't know a whole heck of a lot regarding direct solar heating.

Cool concept though, very interested to see if and how it progresses. Here in Fl, we have no shortage of sunlight thats for sure..

**bendavanza** · 08-07-2009, 10:48 PM

Look at fresnel lenses, you can really concentrate some heat that way and put it exactly where you want it. remember burning ants with a magnifying glass?

chispas · 08-08-2009, 12:47 AM

Not sure if you've come across this page yet, but it's pretty good: Plans for solar thermal, PV, Wind, Heating, Cooling, Cooking, and energy saving projects for Do It Yourselfers

I think it's a great idea, I plan on getting my rig converted over to run on deep cycle batteries and trickle charge it throughout the week with a PV panel.

Good luck and keep us posted!

**Acidjazz54** · 08-09-2009, 02:10 AM

CodeRage & bdavanza, setting up a parabolic reflector or lens would be an awesome idea but I don't think I have the right set up for it unless I'm missing something.

I was reading one of the sites on the link that chispas posted and here's what I found about Flat Plate Collectors "The most efficient collector design maximizes solar heat gain, minimizes heat losses, and provides for the most efficient heat transfer from absorber plate to tube. Operating temperatures up to 250°F (121°C) are obtainable, although neither common nor desirable. Remember, you want hot water, not steam."

Now I understand that my "box" probably won't be the most efficient design but 80 degrees seems like a good cushion. I'm kind of curious if I can make it to 170. I think a test within the next week or so may be necessary.

Sawdustguy · 08-09-2009, 11:56 AM

According to this website: Lesson 2: Solar Hot Water Basics | Pennsylvania Solar Course, on a summers day 180 to 200 degrees is achievable.

Quote:

Two temperature gauges in the closed loop and one in the water loop are optional, but valuable indicators of the system’s function. One gauge on each side of the heat exchanger in the collector loop shows the temperature rise across the collectors and the temperature change across the heat exchanger. A temperature difference of 15 to 20°F indicates effective system operation. One temperature gauge in the water loop between the exit of the heat exchanger and the entry to the storage tank will display the current temperature of solar heated water entering the storage tank. The temperature gauges should have a range of 0 to 240 or 300°F. A hot summer day may produce water temperatures in the solar loop around 200°F, although normally 180°F is the maximum temperature attained.

**bendavanza** · 08-09-2009, 01:31 PM

Makes me think about using something like this
53" HUGE FRESNEL LENS linear solar water heater OVEN - eBay (item 170369763016 end time Aug-12-09 12:57:24 PDT)

**Acidjazz54** · 08-10-2009, 03:44 AM

Man. Looks like from that YouTube video you could just set up your boil kettle in front of that lens and let 'er rip.

Sawdust, I was thinking possibly a drain back system. We don't have the cold climates like PA but I was afraid of the stagnation temperatures of just a simple closed loop. The only thing that kind of sucks is the fact that it will involve a little more hardware (pumps etc.)