This page, first posted April 2020 is still under construction.

Rustic Geothermal Concepts For Cold Winters

Based on two years of geothermal experimentation, I am summarizing my observations of large radiator sizes with less-heated water, as compared with fired boilers. It is known that one-sage heat pumps in geothermal systems are the most efficient space heaters, which reduce energy consumption, but which limit the available heater temperatures, which therefore demands much larger radiator sizes. This would be expensive with usual radiator materials except that I adapted my wife's planters to incorporate radiators, so as not to use up floor space with this new heating system. This has worked very well for us, saved lots of money to allow the upgrade, and also it actually theoretically reduces industrial impacts on the environment. However, this low cost drain pipe challenged the prototyper!

Maximizing the size of a geothermal radiators is easily done within a new the floor or else in a crawl space below it, (but we have already lived in our house for decades and this kind of technology was not commercially obtainable when I searched for it in the 1970s). This past winter I added some large pipe in a high ceiling space to test the cost of pumping water higher up, which read twice the circulator pump power consumption, for just a few feet or a meter of added height. In the first year I placed pipes on top of wooden floors, to reveal all possible issues which has revealed quality of my low cost cement connection-adapters. If readers ask for it, I will add more information and pictures; however for now, this page focuses on sub floor concepts for space heating; and leaves the further research of producing low cost pipe connectors for another day. As far as I know applying for code approvals would be a large task in itself, where do-it-yourselfers are permitted to build their own homeequipment here in Maine.

Approximate conversions, 6" Inside diameter equals 15 cm, 110 gallons equals 416 litres, 88 galloons equals 333 litres'

913 feet equals 278 meters, 718 ft equals 218 meters, 10't X10' equals 3m X 3 m

First is a modeling effort to estimate the amount of tubing which may fit in a 10 ft X 10 ft space, by laying out two spiral pipe paths, joined at center with smaller pipe. All measurement are approximate and this design effort was to mathematically estimate the possible water capacity for lower geothermal temperatures, in a typical slab.

Larger floor spaces are easier to fit more pipes, which in turn provide more possible heat storage, which provides several advantages. 1.Heat storage guards against power outages. 2. Heat storage conserves on peak-power usage during daytime hours, which helps society moderate wasted infrastructure, and potentially reduces utility-investments for the same, obtainable, heating benefits. 3. Embedding large pipe circuits in concrete slabs conserves on concrete. (The downside is the challenge of new placement methodology and code acceptance, or as an added cost for the pioneering buyers of new systems, and finding trusted contractors who are willing to master new systems.


My economical experiment featured the expediency of Portland cement, (slightly modified), to seal and waterproof all plumbing connections. The plastic plumbing and drain pipes certainly exhibit a significant difference of expansion and contraction in relation to cement and so wire clamps were fashioned for thin pipes "to clamp onto cement adapter-inserts" and furthermore short copper pipe pieces were inserted inside plastic tubbing which embedded cement-tank-walls, (and also embedded inside customized cement plumbing adaptors). Cement seals are very expedient money savers, but at this point are experiments, where building codes might permit innovations, such as rural localities, to test new avenues of conservation.

Cement junction-adaptors are very conservation minded, for adapting different sized pipes and tubing, while same size connectors could use standard fittings with sealants. For a Portland cement modifier I used an industrial grade of methocell, (sources may be found on today's web-search-shopping: copy-paste: concrete + methocel + cement). These additives hugely improve the cement-cure and bonding, and also improves workability and stickiness. For the larger plumbing-junction-adapters I added PVA fibers to improve crack resistance and 3d-shaping. Meshes and wound wires are conceivably desirable additions, although I was testing the bottom line in my experiments. See this earlier blog-page for my experimental size-adapter methods.

A floor with tubing as a radiator, integrates a large capacity of water heat storage, which can double over as summer house cooling.

Multi circuits of tubing can zone parts of a house to conserve energy costs. Next below is a concept of enlarging a heat pump exchanger inside a tank, to trade a larger size pipe for a possible reduced circulator energy consumption. Coloring of pipes in pictures is primarily to distinguish circuiting options.

This illustrated concept is interesting because cheaper tubbing can hypothetically be used, thus allowing for a conceivable, much larger exchanger surface area which consequently needs less agitation energy, for the same work of exchanging heat.

When inserting smaller pipes in cement junctions, I did notice the lower costing, older vintage PE, "black plastic tubing" was difficult to keep leak-proofed against cement on it's outer perimeter, during the cooling down phase of the system where coefficients of expansion differences, between the two material types, do differ and thereby causing a slight amount of leaking. A remedy is to insert a short little copper or stainless pipe inside the plastic to reduce shrinkage and to improve resilience of the connection.

My conclusion is that leak proofing is possible with the inserts for cement outside of the smaller plastic pipes, and also with stronger, large pipe clamps, where I had tried simpler wire twists on the large pipes. The ferro cement or concrete could be improved over my work by use of a high quality vibrator tool adapted to pipe fitting, which in fact is likely a nonexistent tool, and one which should use possibly ultra sonic vibrations and shaped effectors to address the round shapes of pipes. This was far beyond my meager budgets, but I would be glad to assist others who might like to advance these arts, as time permits.

I am still adding the further possibilities for use of these thin walled drain pipes, as time and the drive to do so permits. However want to report the following right away:

Just days after my first posting of this page, I discovered a leak under my wife's plants. I had already written that when heated, these corrugated drain pipes tend to snake and lengthen due to softening of the plastic, which reaches a point where a small water pressure expands the free-standing, unsecured drain pipe, almost like an accordion. This should prompt others to deal with this factor early in the planning stage. Not feeling at all discouraged, I point out that the concepts drawn above, duly secure the pipe very firmly, so that this is really a research finding which has been solved.

Material Efficiency Prototyping
#Heat Pump
#Floor Heating
#Water to Water
#Ground Source
#High COP