Saturday, July 20, 2024

Photovoltaics for vapor compression refrigeration – pv journal International


Chinese scientists have developed a PV-driven direct-drive refrigeration system for digital gadget cooling. The proposed system thus far gives low exergy ranges, however its value is decrease than typical vapor compression refrigeration applied sciences.

Researchers at Hebei University of Technology in China have designed a photo voltaic photovoltaic direct-drive refrigeration system with low power consumption for top heat-flux cooling of digital units.

“The proposed system integrates photovoltaic energy technology with direct-cooling and vapor compression refrigeration (VCR),” mentioned lead creator of the analysis Xiaohui Yu. pv journal. “The mixture of micro-evaporator and direct cooling methodology can obtain good warmth change effectivity.”

The system consists of two subsystems: a PV unit together with a battery and a most energy level monitoring (MPPT) controller; and a VCR unit consisting of a DC rotary compressor, a fin air-cooled condenser, an digital enlargement valve, an embedded direct cooling evaporator, and a dry-filler.

In the proposed system configuration, the DC rotary compressor compresses the refrigerant right into a excessive temperature and excessive strain fuel, which is then despatched to the fin air-cooled condenser to launch warmth. “The refrigerant turns into a state of gas-liquid two-phase stream with low temperature and strain by the digital enlargement valve and at last goes to the embedded direct cooling evaporator to soak up the warmth of the digital units,” defined the researchers.

The PV unit powers the DC compressor and the MPPT gadget is used to manage the charging and discharging of the batteries.

The scientists emphasize that the heating energy of the system and the pace of the compressor have an incredible affect on the exergy efficiency of the VCR subsystem, which they are saying is said to the depth of photo voltaic radiation. Exergy is the utmost quantity of labor that may be accomplished by a stream of power because it involves equilibrium with a reference surroundings.

The group examined the exergy and financial efficiency of the system below completely different working circumstances and located its coefficient of efficiency reached 8.5 when the heating energy and compressor pace are 400 W and 4350 rpm, every one.

“If the common depth of photo voltaic radiation is 776.5 W / m2, the photovoltaic cells of the introduced system with an operation of seven hours generate 1.81 kW h of electrical energy, of which 24.9% of the electrical energy is utilized by the VCR subsystem, ” it added. “The relaxation is saved and may present this subsystem to proceed operating for five.3 hours with out photo voltaic radiation.”

The teachers described the exergy efficiency of the PV unit and the compressor as inadequate. “The PV cells have the biggest exergy destruction of 1059.4 W, accounting for 91% of the overall system destruction. Showing the second largest exergy destruction, the compressor reaches 86.3 W and accounts for 7.4% of the overall exergy destruction,” they added, noting that rising the pace of the compressor from 4350 to 6500 rpm resulted in a two-fold improve within the exergy destruction of the compressor itself.

Their financial evaluation, nonetheless, reveals that the system is 79.5% cheaper than typical VCR methods, and that its payback time is about 2.2 years.

“Currently, the embedded direct-cooling microchannel evaporator has been examined on our check bench for long-term operation,” mentioned Yu. “Our work will information the long run improvement and use of this technique. In addition, it should promote the event and use of photo voltaic photovoltaic straight powered vapor compression refrigeration methods for heating, cooling and home sizzling water.

The system is described within the paper as “Energy, exergy, financial and environmental evaluation of photo voltaic photovoltaic direct-drive refrigeration system for digital gadget cooling,” which was lately printed in Renewable Energy.

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