News & Science

First Farm SunFridge completed in Picholiya, Rajasthan

Cool Sun Project researchers, Drs. Chopra and Beaudry, traveled to Picholiya, Rajasthan India to finalize the construction of the first Farm SunFridge. The SunFridge is located on the field of Mr. Lokendra Singh, near the village of Picholiya and adjacent to a start-up fruit and vegetable processing plant managed by Mr. Jitendra Chaturvedi, CEO of the NGO Krishak Vikas Santhan, our local partner. Our goals were to evaluate the refrigeration system, install a HOBOTM remote monitoring station, and fit and begin testing of a self-built sense-and-control system for regulating the demand of the refrigeration equipment based on available sunlight.

The newly operational Farm SunFridge at village Picholiya, Ajmer, Rajasthan

The trip was a success. On the first day, within a couple hours of startup, the temperature in the storage room fell to 6 °C. However, we found (as expected) that clouds interfered with the continual running of the system. During cloudy periods and early and late in the day, the power from the 14-panel solar array was not sufficient to supply the refrigeration at the high demand setting. This caused the inverter (MPP solar 5 kW) to overload and shut down temporarily, restarting itself after 15 minutes. The loss in cooling time was determined to be too great. This was the reason we developed the sense-and-control system to regulate the demand of the refrigeration system. The sense-and-control system was installed and could match the demand of the refrigeration system with the available sunlight successfully. However, we felt we needed to make further improvements to refine thresholds and more rapidly adjust to declining power availability as clouds blocked the sunshine.

Sense-and-control system to match demand of refrigeration system with sunlight.

Over the three days of the trip, we continued to observe the performance of the Farm SunFridge. We found that the photovoltaic (PV) array would supply enough energy to run the refrigeration system between 8:00 in the morning to 6 p.m. although sufficient power to run the refrigeration system at high demand (roughly 9 Amps at 230 V) was typically only available between 8:30 and 4:30 p.m. We successfully installed the HOBO station and began collecting data that could be viewed publicly on our Public Dashboard. The older dashboard from March-May 2020 is at Old_Public Dashboard

We left Picholiya pleased with progress and performance of the first Farm SunFridge. On the last day of our trip, a local farmer, Tilok Devasi, who had heard of the system, stopped by with some flowers to see how well they might store.  It was only a few lugs of flowers in this trial run, but it marked a new beginning for the Cool Sun Project.  We were in business.