Direct-Solar Air Conditioning: a scientist/engineer/achitect who worked for the U.S. Department of Energy on occasion, once told me about using solar heated absorption air-conditioning techniques, to cool buildings using solar thermal energy. This is the same technology as that used for R.V. gas refrigerators or gas or kerosine refrigerators used in homes. There used to be an Arkansas company named, "Arkla-Servel", that specialized in gas-fired air conditioning and refrigeration systems, which were then converted to using solar or other sources of heat in the late 1970's.

    This architect told me that there was once an entire DOE funded condo complex built with solar air conditioning systems from Arkla-Servel.

    This was David Scwhartz, a Carnegie-Mellon educated architect/engineer who once worked for some Denver Stock Exchange listed, DOE funded companies from around 1979 to the mid to late 1980's or so. Schwartz and business partners had started a private Boston or Cambridge company in 1975 or 1976 or so, Great Natural Structures, Inc., which designed and built a solar heated office building using a new design element called, "Compound Parabolic Concentrators", to improve normal flat-plate solar thermal collector design. This type of collector using "light troughs", or "light funnels", was incorporated into an entire south wall of this 3 story steel-polyurethane-sandwich skinned, concrete-thermal-core office building for Abt Associates in Cambridge, MA, which was occupied by late 1976.

    Abt Associates Solar Building Under Construction probably 1976
    Notice the extruded aluminum "CPC" solar collector
    with "light troughs" oriented horizontally. Each trough contains
    the solar heat receiving pipe.

    The photo is only an unfinished mock-up of one unfinished panel of the many which would soon cover that entire sloping wall when finished, but also covered with one or two layers of high-quality glass. The solar assemblies are attached, and are above another layer of steel-polyurethane-sandwich panels.

    The building probably still stands in 2013. The solar system froze up with burst pipes in the winter of 1976/1977 due to a leak of anti-freeze/water and was probably never repaired. Popular Science Magazine reported on Great Natural Structure's accomplishment when the building was finished in late 1976, which is how I knew about it.

    Carl Abt, in retirement as former CEO and founder of Abt Associates, responded to me by email when I found his email address online somehow using in early-mid 2008, that the solar system on this building from 1976 had never been repaired from that freeze-up and pipe-cracking in early 1977. That email is still in my online email account today in 2013. This contradicts what an Abt Associates security guard told me by phone, that the system had been repaired and was still working as of early-mid 2008. This is untrue, I believe, unless they fixed it recently.

    I already knew that it had frozen up in early 1977. I was with Schwartz and his business partner when the other engineer or architect checked the specific gravity of the liquid in the solar collector/wall of the building that winter. The anti-freeze/water mixture had leaked out very slowly, then was automatically replaced slowly by pure water, so the system had probably frozen up not long before they checked it when I was visiting, and had cracked pipes. Abt Associates was already suing GNS in court for other reasons at that moment, before the solar system freeze up, and we were trespassing in the building when this GNS executive/architect checked the specific gravity of the solar collector fluid.

    We then walked around the building in the snow and noticed what looked like water trickling out of the bottom of the solar collector assembly attached to the sloped wall of the building; however, it could've been snow melting on the glass-surface of the collectors. The building then had a small back-up gas furnace that was sufficient to heat the building without solar energy input.

    The solar system and back-up furnace had been working well according to Schwartz and associate before the freeze-up of collector fluid in late January or early Feb. 1977 due to the undetected small leak, and nearly all the space heating for the building had been supplied up to that point by the sun that fall and into winter.

    Until I found the above photo online at the Abt Associates website using, I didn't know about the reinforced-concrete, thermal-mass, core of the building. I only saw it once in the winter of 1977. I had always thought it was almost a completely steel-polyurethane-sandwich prefab. building. The concrete mass of the building is used to store heat passively, and stablilize the temperature of the building, and to provide most or part of the main structure of it, apparently.

    However, the solar system could've been repaired at some cost according to the architects and builders, Mr. Schwartz, and the other guy whose name I can't recall. Note that according to, Schwartz changed his name. I don't recall his new name which also produced for me a few years ago.

    Solar-refrigerator: if using solar photo-voltaic panels to create "12-volt" electricity to charge batteries, it's much more efficient to power a compressor cooled fridge, rather than an absorption-style RV refrigerator, which use tons of electricity when in electric mode.

    Most people today are recommending that RV fridges be used in remote locations that utilize solar energy; but RV fridges use a ton of electricity when in electric mode. Norcold, one of the RV refrigerator companies, used to make a line of compressor type RV fridges which ran on 12 volts DC.

    Some RV absorption type refrigerators can also run on 12 VDC, but in that mode, they use a prohibitively large amount of power. I don't know who makes 12 volt compressor-type fridges today, but that would probably work better with solar photovoltaic/battery installations which don't rely on propane or butane as a backup.