Reviving SunnyJohn's Work

8/4/2017

Recently it was brought to our attention that elements of John Cruickshank's former website (sunnyjohn.com) were available in web archives. What was considered lost forever had been found! John was one of the foremost contributors to climate battery knowledge (he referred to them as SHCS - Subterranean Heating & Cooling Systems). John has since passed on, but his memory and contributions are still appreciated today.

We didn't want to risk losing the materials he published on the web during his lifetime, so we decided to make our own archives of his work. To continue the spirit of open-source knowledge that he promoted, we've re-published his SHCS Calculator, revised and modernized to the Climate Battery Calculator V2.0. Please try it out for your own climate battery design, and help us to spark conversation and sharing of knowledge around this wonderful simple technology.

8 Comments

Hex

8/12/2017 08:17:12 am

As a friend of John`s and a frequent visitor to his plain to sea forums (circa 2009- 2010 prior to his passing) its good to see his work continues. I consider myself very lucky to have had John around to bounce ideas off when i designed my system which has performed well for 8 years or so.
There is a lot of misinformation out there with regards to SHCS, i always try to educate folks whenever i can but it usually falls on deaf ears where they`ve already installed the tubing. I guess they`d rather have a system that doesnt work very well versus digging it all back up ;)

Hex

8/17/2017 07:15:11 am

Just a heads up. The calculator doesnt account for the tubing displacement when it calculates the weight of the mass. With the example greenhouse, it overestimates by around 7% as 3,150ft of tubing will displace 274 ft3 (21,991 lbs) of mass.
Setting an arbitary maximum airspeed of 10ft per second will limit the flow to approx 52cfm per tube regardless of the tube length is 25ft or 35ft. The calculator recommends using 1.33ft of tubing per sqft of floor which would be 1596ft but the example greenhouse (1200ft2 floor uses 3150ft which could be a little confusing for some ;)
My installation uses the old 1.33 ratio but not the 25ft-35ft minimum tube length or 10ft/sec maximum tubing airspeed. I find airspeeds upto 20ft/sec useful for both cooling and heating. For cooling i would recommend increasing the fan speed to "reduce" the delta-T between the inlet and outlet, a few degrees higher output temperaure can easily equate to twice the heat transfer due to the higher flowrate. A bucketful of 70F air from the outlet is a lot better than a thimbleful at 68F in the same time frame ;)

Will

8/18/2017 04:51:00 pm

Great feedback @Hex, I adjusted the example arrangement in the calculator to better reflect an ideal climate battery, based on established parameters.
I appreciate you sharing your experience with using the climate battery for cooling also, and increasing the airspeed to minimize deltaT between inlet and outlet. That is an interesting technique, and great to hear that it's effective!

Kory

5/17/2018 12:16:29 am

Hello Hex, I am thinking about getting a 33' geodesic dome thats 15ft tall in the center from growing spaces but would like to put one of these systems underneath the floor of it can you please help me design the best system I own a HVAC company so understand alot of what you say just have never done a system like this.... I live in Montana and wanna grow year round... What size pipes and fans are most effective ?? What type of pipe should I use galvanized metal or plastic ?? What type of backfill is best a rock and crusher finds or just soil & rock ?? How deep should I before I start the loop ?? Should I do a recessed concrete wall and insulate the exterior of that ?? So many questions and videos out there I'm a bit confused which way to go ??

Thank you for any help 👍

Hex

8/19/2017 09:09:50 am

Hi Will,
Its easy to miss the small things and its the small things that usually make the biggest difference. For cooling i`d recommend using an airflow rate to maximise heat transfer but importantly it only keeps pace with the incoming solar gain. If the airflow outruns the incoming gains (rapid drop in greenhouse air temp) it will cost more in electrical power (fan) but you`ll gain nothing from it. The Hare and Tortoise race is a good example, high flow, stop and start versus a constant steady flow ;)

susan harder

12/29/2018 08:18:23 am

This sounds like a simple system, but when I read everything it all sounds so complicated. I wish someone would create reference materials that make all of this a little easier to do. Maybe someone has and I am just missing those pages in the websites. For example, every thing I have looked up says 2 meters down the soil temp is fairly constant, but a video I watched of a man in Nebraska, he says his is 8 feet down. I live in Ohio and have a several 12' X 20' greenhouses I would like to start putting systems in. Is there simple instructions out there for anyone like me?

Nick

1/23/2019 09:43:41 am

Hi Susan,

I'm just returning to this subject after a series of segways over the years. I'm by no means an expert. However, perhaps I can help a little.

Short-ish answer to the soil question: I think that even in a climate like yours, you'll want to insulate the foundation/perimeter of your greenhouse, down to below the frost line. 4-6' is as deep as you'd likely go with your foundation & soil mass no matter what. I doubt your frost line is that deep but you'd likely insulate the entire foundation anyways.

If you want to keep it *really warm, you'll want to insulate the "floor" of your soil mass well as the sides.

I know the feeling you refer to, simple yet complex. One reason this idea has caught on is the remarkable talent Mr Hobbit had for explaining. Just keep at it with the investigation, and don't rush into your "final" build until you feel confident.

EBo

3/22/2019 12:00:12 am

Maybe as people build these they/we can take some measurements and report how well they work -- generate case studies. This will also help tune the models for prediction on when we might need to turn on auxiliary heaters and fans (hopefully never, but reality is a harsh master).

Reviving SunnyJohn's Work

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