Development and analysis of a compact cooling system using the microcompressor

Abstract

For electronics cooling, the matching between size and efficiency is a desirable aspect of the design of cooling units. Hence, the compact cooling units are suitable for this area of refrigeration due to high capacity by size ratio and lightweight. For this purpose, Embraco developed a new refrigerating system for small enclosures and command panels with the use of a new miniaturized linear compressor called microcompressor. This unit consists in an outdoor mounted air-conditioning with finned-tube heat exchangers whereas the microcompressor is a direct current (DC) oil-free compressor that uses R-134a as refrigerant fluid. The paper presents a detailed description about the cooling unit and its performance tests. In order to run all experimental tests, a cooling unit calorimeter was assembled. In the experimental facility, the ambient temperature was varied for evaluation purposes whereas the bulk temperature inside the enclosure was kept at 35 °C via an electric heater. A commercially available thermoelectric system used for electronics cooling was also tested and compared with the vapor compression system. The results have shown that the microcompressor unit presented a coefficient of performance (COP) approximately two times larger than thermoelectric solution and higher cooling capacities were achieved under low ambient temperatures.

A Review of Small-Scale Vapor Compression Refrigeration Technologies

“…Detailed numerical models have been developed and validated to improve the design and therefore the performance of these compressors [86,87], as well as experimental tests [55], where a constant-speed, oil-free linear compressor was used for electronics cooling in aeronautical applications, in which the mass flow and cooling capacity were controlled by varying the piston stroke. This same micro compressor was presented by Ribeiro [54]. It is a hermetic linear compressor with cylindrical form and 60 mm in diameter and 160 mm in length that weighs 1.3 kg.…”

“…The need for compact telecom cooling units that may perform as efficient substitutes for thermoelectric coolers and the scarcity of studies in the literature motivated Ribeiro to test a VCR system for this application. The initial work [53] presented a prototype made of a linear oil-free micro compressor, finned tube heat exchangers as condenser and evaporator, and a capillary tube as an expansion device, operating with R134a. The overall dimensions were 528 × 127 × 96 mm 3 and 3.1 kg weight, and it used 59 g of optimized refrigerant mass and a 1.10 m long capillary with 0.518 mm diameter.…”

“…In a second work, Ribeiro [54] proposed a similar experimental apparatus, except that an additional pre-condenser and post-evaporator were added to the system as seen in Figure 13, causing an increase in the dimensions and weight (660 × 200 × 120 mm 3 , and 8 kg). The aim of adding these devices was to partially condense the refrigerant in the pre-condenser and then send it to the post-evaporator, which was a serpentine tube in contact with the compressor, to decrease the shell temperature, permitting its suitable operation in hot climates.…”

Design & development of a prototype of the layman’s air-cooler

“…Henceforth, by utilizing silica gel, water tank is not required and also silica gel absorbs moisture so that it will also reduce the weight of cooler and helps to maintain a hygienic environment. In the paper [2], the technology developed in the paper, "Development and analysis of compact cooling system" involves a commercially available thermoelectric system used for electronics cooling was also tested and compared with the vapor compression system. The results have shown that the micro compressor unit presented a coefficient of performance (COP) approximately two times larger than thermoelectric solution and higher cooling capacities were achieved under low ambient temperatures.…”

“…So, we have defined our problem statement as "LAYMAN'S AIR COOLER". As it is probably one solution which not only is cheaper as an appliance, but also uses lower power than conventional air conditioners [2]. In big cities, the problem is associated with the space and high installation cost of cooling appliances.…”