Solar refrigeration

Solar refrigeration

In 2015, Tesla founder and CEO Elon Musk quipped, “We have this handy fusion reactor in the sky called the sun. You don’t have to do anything. It just works. It shows up every day and produces ridiculous amounts of power.

How lucky are we that we have nature’s finest powerplant visiting us every morning? Using solar energy is about taming the mighty sun, taming a source of energy that is perpetual in existence, has global outreach, is nontaxable and is basically a collaboration with nature. With nonrenewable fossil fuel supplies running out on one hand and the world’s energy needs increasing on the other hand, the world’s energy system is preparing for its transition into clean energy. One of the top contenders for this clean energy is the solar energy. The transition, especially in the electricity sector has effectively become unstoppable. According to The Renewables Global Status Report (GSR), released annually by the Renewable Energy Policy Network for the 21st Century (REN21), a think tank ,some 181 GW of new renewables capacity was installed in 2018; it now makes up more than one-third of global installed power capacity .of the new renewable energy capacity installed in 2018, 55 percent (about 100 GW) was solar PV; wind power had 28 percent, and hydropower 11 percent. Thus, it is clear that the future of the world basically depends on solar continuing to boom.

The brilliance and unfathomable advantages of solar power have enticed the entrepreneurs to come up with pioneering ideas. One such conception is of the ‘solar Refrigerator’. To refrigerate is to preserve. It’s a technique of safeguarding something by cooling, cooling an object to a set temperature, usually several degrees or more lower than the temperature of the room in which the refrigerator is situated. This not only has the effect of making the object cooler but, where the object would usually be subject to decay or other chemical processes at the normal room temperature, refrigeration can slow or halt the process, maintaining the object in its current condition for longer than would be possible naturally .The refrigeration has got some immense popularity and significance around the globe. Perishable goods, Fresh meats, eggs, dairy products and vegetables can be stored without spoilage. It can also be used in health sector. For instance, WHO has stated that around 16% of people in Nepal are diabetic patients and many other diseases as well whose vaccines are strictly required to maintain at a fixed stated temperature with proper cooling which has no second choice to refrigeration.

Solar refrigeration is just a case where the power to run the compressor is provided by the solar thermal energy or the photo voltaic cells (PV). It’s a boon to store the medicines and vaccines of a diseased person. The setup simply consists of a DC compressor set to circulate the refrigerant designed to run in absence of electricity grid lines. A further research insisted that not even any batteries are to be employed and hence can run with the direct PV power having met the requirements. A phase change material with the ability to release/absorb the sufficient amount of energy during the phase transition is used to store the thermal energy (replacing the chemical energy stored through batteries) which helps keeping the desired temperature in absence of sunlight maintaining around 36 degrees Fahrenheit. This idea was first introduced in 2011 by the innovators in NASA’s Johnson space Center and was patented. Namibia and South Africa has been using it for years with a bit different modelling.

Though no remarkable progress has been made yet in solar energy sector in Nepal and though Nepal usually has hydro dominant policies, the solar power is well suited and very much needed. On average, Nepal has 6.8 sunshine hours per day with the intensity of solar radiation ranging from 3.9 to 5.1 kWh per meter square, with a commercial potential of solar power for grid connection estimated to be 2,100 MW. Despite its hydro dominant policies, solar energy and in this particular case solar refrigerator can be ‘the next big thing’. Talking about the possibilities, first, solar refrigeration is completely environment friendly. So, it harmonizes with our goal of sustainable development. Moreover, in the context of a developing country like Nepal with difficult land structure, electricity grid lines setup is a major challenge. There isn’t a need and market of bigger and costly solar items as of today. Instead, an inexpensive, efficient, commercialize and small capacity solar refrigerator that can run several days in absence of sunlight is preferable. Besides, the question of longevity of the device is much good enough as from its prototype use and if required is scalable from 50 liters up to an entire room cooler as well. The repair and maintenance also aren’t a headache after its proper installation. As per the data, Vaccines transportation has become much easier with solar refrigeration and availability of vaccine at service points has saved lives. At present, the practice of ‘cold chain’ for vaccines are maintained by the kerosene or gas-powered during transportation but the risk of firing, the initial and maintenance cost of this fuel, solar refrigerators are being encouraged throughout the world and especially in poor remote countries like Nepal.

The manufacturing and production of solar refrigerators is not as easy as stated. Much prior research and study in this system’s technology, climatic feasibility and people’s affordability is required. The availability of various component parts and their durability/reliability may a hindrance in its construction. Major concern is about the skilled manpower and the user feedbacks as well.

The above stated possibilities and the strong desires are always an upper hand to a better entrepreneurial design and ultimate manufacturing. If made to meet the people’s demand as expected, the solar refrigeration will surely rise above all of its counterparts.

Author: Prashant Ghimire

Batch: BME2074

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