South African scientists have developed an built-in, solar-powered warmth pump and fridge to be used by meals distributors in sub-Saharan Africa. The twin system is powered by two 90 W photo voltaic modules and likewise makes use of waste warmth.
Lecturers from the Cape Peninsula College of Know-how in South Africa have designed a PV-powered built-in warmth pump and cooling system to warmth meals and funky drinks.
The system makes use of a vapor compression refrigeration system with R134a refrigerant. It has two separate compartments for heating and cooling, with a quantity of fifty liters every. The condenser operates at 50 C and is situated below the heating compartment. The evaporator works at -2 C and is positioned above the colling area.
“This association is knowledgeable by the bodily phenomenon that heat air rises and chilly air descends,” the scientists defined.
The warming and refrigerant compartments use the identical compressor. The scientists simulated the system’s warmth load utilizing MATLAB, which confirmed a warmth load of 433.5 kJ and a cooling load of three,550.7 kJ. To satisfy these hundreds, they selected a 12 V DC compressor with a capability from 149 W to 186 W. The lecturers calculated the efficiency of the system utilizing the ANSYS modeling system, estimating a coefficient of efficiency (COP) for cooling at 3.32 and for heating. at 4.32.
They constructed a prototype of the twin system utilizing two small family fridges because the cooling and heating compartments and examined it in Bellville, Cape City. The system makes use of two 90 W monocrystalline silicon PV panels from an undisclosed producer measuring 1,200 mm x 544 mm x 25 mm. It additionally features a 12 V DC battery and a ten A cost controller.
The crew examined the system between December 2020 and January 2021 – the summer time months in South Africa. The outcomes present that the warmth pump heats the new compartment to a most of 55 C throughout peak solar hours, between midday and a couple of pm (SAST).
“Nonetheless, it was noticed that after the door was left open for greater than quarter-hour, a drop in temperature was noticed at 3 p.m. … whereas the warmth pump system was working,” the investigators mentioned. .
The refrigerated compartment reached a low temperature of two C. The scientists additionally in contrast the efficiency of photo voltaic modules with zero- and 30-degree tilt for north orientation. They mentioned they discovered that “the 30-degree tilted PV panel obtained increased irradiance, which precipitated each methods to succeed in their design temperature earlier than midday; subsequently it proved to be probably the most appropriate for the general efficiency of the system.”
The lecturers shared their findings in “A photo voltaic powered fridge and warmth pump for city avenue distributors,” which was not too long ago printed in MATEC Internet of Conferences.
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