CONIFER SOLAR CONSULTING

Jon Klima, Owner
360 Trout Lane, PO Box 23, Guffey, CO 80820
Phone: 719 479-2281,  Email: jon.klima@gmail.com
In business for 37 years

 

• Article 8 - July, 1991

 

FLORIDA SOLAR ENERGY CENTER SCHOOL SURVEY©

 

During the ISES Solar World Congress held in August, a particularly interesting paper was presented by Marvin Yarosh from the Florida Solar Energy Center . The work reported on in the paper was funded by the Florida Department of Education and the Governor's Energy' Office. The paper presented the results of a survey of 48 (out of approximately 82) solar water heating systems on Florida schools. Mr. Yarosh sent me a copy of the report that details the project background, history, findings from site visits, analysis, conclusions, and recommendations. Below are some points that I think you will find interesting. "... The quality of the design and installation have a profound effect on the ability of the operation and maintenance teams to perform their jobs... Design and Installation Problems - Findings and Conclusions:

 

• The SWH system drawings and specifications provided by most of the solar system designers contained insufficient information to ensure the installation of a good system.

• Often, the level of design information provided would require a very experienced installer who could make up for omissions in the drawings and specifications.

• Most of the installations were not performed by people who were experienced with solar water heating systems. Many systems exhibited errors that experienced installers normally do not make.

• There was insufficient follow up of the installation process by the system designer.

• There was insufficient instrumentation provided to permit even basic monitoring of the system.

• The location of valves for relief, air bleed, vacuum breaks and flow direction was often neither consistent nor correct.

• No instructions had been provided for periodic testing of equipment to detect continued adequate performance (checking of controllers, sensors, valves, etc.) Seventy percent of the systems visited had some problem of significance with the control system. The problems usually had their origin in designer installation.

• Either the collector or tank sensor was incorrectly located on two thirds of the systems visited, and therefore an erroneous signal was sent to the controller. The pump was then improperly controlled.

• Sensors were often improperly wired to the controller so the pump was improperly controlled. Thirty percent of all control systems had improperly wired sensors.

• Twenty percent of the systems could not drain the collectors and/or the array, often because of improper piping configuration.

• Twenty percent of all systems showed damage from freezing.

• Twenty percent of the systems allowed water heated by the-backup system into the solar loop.

• Thirty percent of all systems had no instrumentation, and only ten percent of all systems had minimum acceptable instrumentation.

• Only one system out of 48 had an adequate operation and maintenance, manual. Ninety percent of the systems had no information at all.  

 

Operation and Maintenance - Findings and Conclusions:  

• In our survey of counties with installed solar water heating systems on schools, the responses to our inquiry on system condition indicated that approximately 66% of the solar systems were thought to be operating satisfactorily or nearly satisfactorily.

• In subsequent site visits to these same systems, we found that only 15% of the systems were working at or near a satisfactory level.

• Some of the systems reported as satisfactory were, in fact, not operating at all. Some were circulating fluid through the collectors 24 hours a day, while others were operating very poorly or were even operating at a net energy loss.

• About 30% of the systems which were not operating or were operating poorly were brought back into reasonably satisfactory operation after we made minor repairs, largely to the control system. Forty percent of all systems visited were operating after our initial visit.

• We found little or no evidence of training of system operators. Often no individual operator was designated for the system.

• We found that in almost all systems visited, additional specific training would have been useful for maintenance personnel.

• Forty-seven percent of the systems had deficiencies in insulation. Much of the insulation suffered from ultraviolet deterioration and inadequate upkeep

• One half of the instrumentation did not function well. Thirty percent did not function at all.  

 

Recommendations: (Not all are shown here)  

• A clearly written operation and maintenance manual for the specific system must be furnished.

• All systems should be designed with enough instrumentation to permit the operator to determine if the system is operating correctly or not. Minimum measurements include:

• The temperature of the fluid going to the collector array.

• The temperature of the fluid coming from the collector array.

• The fluid flow rate through the collector array.

• An indicator (such as a light) that the pump was powered.

• A two-year warranty on the system should be provided.

• We recommend aluminum tape wrapping or aluminum jacketed insulation as preferable to paint for protection against UV degradation. Foam glass insulation seems to stand up very well in outdoor use.

• The solar system should be designed with a separate solar storage tank.

• No backup (fossil fuel) heated water should pass through the collector array.

• The solar storage tank should be as close as possible to the collector array, to the backup system and to the load. A vertical tank is preferable to a horizontal tank for improved temperature stratification.

• We prefer the use automatic air vents to manual ones. The discharge of all relief valves should be consistent with codes."

 

One last item from the report, "...In extreme cases, we met school personnel who were unaware that there was a solar system on the school."

 

It's interesting to note how many of the above items seem to appear all too often in the residential solar systems in COSEIA territory.

 

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