Thermal performance characterization of a photovoltaic driven domestic refrigerator

This paper presents the cool-down, warm-up and steady state performance of a 100 W AC operated domestic refrigerator powered by a field of photovoltaic panels, a battery bank and an inverter. It is shown that there is no degradation in the performance when a non-sinusoidal waveform AC source is used to operate the refrigerator although it may involve only a slight additional heating of the hermetic compressor. Thermal mapping of the temperatures at various points on the refrigerator is provided for steady state, cool-down, warm-up, periodic opening of the door and ice making. An energy flow diagram is given for a steady state sunny day operation. Major sources of losses are identified

Photovoltaic Panel-Generator Based Autonomous Power Source For Small Refrigeration Units

This article describes an autonomous power source for a domestic refrigeration unit which is powered by a field of photovoltaic panels backed-up by a generator set. Salient design features and results from some of the tests on the unit are presented. Methodologies for reliable and efficient operation of the refrigerator have been evolved. A finite time delay between cut-out and cut-in of the compressor, changes in invertor design to meet the demands at start and at run of the motor, choice of battery capacity so as to eliminate the need for a power conditioner are found to result in energy conservation. The entire unit has been made from indigenously available components and uses minimal electronic controls. Such units have applications for the storage of vaccines and life saving medicines which require uninterrupted refrigeration, in medical shops, rural health centres, veterinary laboratories, etc

Uninterrupted power supply for autonomous small refrigerators

The objective of this paper is to describe salient features of a small refrigerator powered by a field of photovoltaic panels backed up by a petrol-start, kerosene-run portable generator set. Such units find applications in medical shops, veterinary applications and storage of vaccines in primary health centers. The modular arrangement allows use of certain components as a part of an uninterrupted power supply system for such refrigerators. Some preliminary results on temperature distributions and performance data are also presented

Lead acid batteries in solar refrigeration systems

Batteries play a vital role in solar photovoltaic refrigeration systems. Despite breakthroughs in operational characteristics of various components of such systems, leadacidbatteries continue to be the only viable electrical energy storage devices as of date. The purpose of this paper is to report the results of characterization of a leadacidbattery system as a component of a small capacity uninterruptedrefrigeration system. The charging characteristics on solar energy, mains anda generator set poweredby an internal combustion engine are presented. It is shown that through a judicious choice of capacity and load matching, the maximum power point tracker can be eliminated

Diurnal and environmental characterization of solar photovoltaic panels using a PC-AT add on plug in card

This article describes the development of an instrumentation system for characterizing photovoltaic panels. It uses an add on card (which contains DAC, ADC and digital input/output ports) in conjunction with a PC-AT. The panels in a field are selected in succession through a set of relays actuated by the digital output port. The selected panel is loaded in discreet steps by a transistor loading circuit which is activated by the digital to analog convertor to trace the most significant portion of the I-V curve. The data shows that the power output is invariably lower than that specified by the manufacturer. The reasons for drop in output have been analyzed. It is shown that these effects can be represented by the curvature of I-V characteristic at the maximum power point (OP). The loss of power due to accumulation of dust and the increase in temperature of the panels can be significant