Modified Operating Parameter-Based Iyer Correlation for the Coefficient of Performance (COP) Prediction of Different Fluid Pairs in Double-Effect Vapor Absorption Refrigeration (VAR) Cycles

Vapor absorption refrigeration (VAR) is a sustainable alternative to the conventional vapor compression refrigeration (VCR) cycle, owing to its lower non-renewable energy requirements and potentially for exploitation of renewable energy sources. Traditionally, the coefficient of performance (COP) of the conventional single effect VAR cycle is considerably lower than VCR cycles. This provides room for improvement which can be attained through double effect VAR cycles that provide relatively higher performance. The COP of the dual effect VAR cycle is enhanced due to the waste/rejected heat energy utilization from the condenser or the absorber into a secondary generator. Models that correlate the COP of the double effect VAR cycle with operating parameters are not available in the open literature, with Iyer’s correlation being the only exception. This work applies this COP correlation using literature data for double effect VAR that operate with a variety of refrigerant and absorbent pairs. A comprehensive Mean Absolute Percentage Error (MAPE) analysis is performed for more than 2028 data points of various fluid pairs. Results reveal that MAPE (86.6–839%) values appear to be quite high for the reported correlation. Furthermore, the model is optimized using the proposed data set, considerably reducing the MAPE up to 36.03%. The results also indicate that due to the lack of fluid-specific parameters, the application of this correlation may not support the development of new double effect VAR cycles. Therefore, it is crucial to establish a performance-based correlation that considers both operational parameters and fluid parameters to assess the performance of new and efficient dual effect VAR cycles.

Performance Investigation of a Vapor Adsorption Refrigeration System Based on Adsorption/Desorption Time and Heat Transfer

In the past two decades, the development of sustainable refrigeration systems such as thermally operated vapor adsorption refrigeration systems achieved unparalleled growth in the research world as compared to conventional vapor compression systems and even thermally operated vapor absorption refrigeration system. Yet, the commercial success of the adsorption refrigeration system could not be achieved due to mainly its higher space area required per kilowatts of refrigeration capacity. With the focus to look improvement on this issue, the performance of the adsorption refrigeration system has been studied concerning adsorption/desorption time and heat transfer of adsorber. It is proposed to reduce the adsorption/desorption time, due to which the concentration (ratio of the mass of adsorbed refrigerant to the mass of activated carbon) will not reach its equilibrium value, but it is possible to get a higher mass flow in a shorter period. In turn, the cooling capacity will increase. In view of this, a mathematical model has been developed to study the performance and applied to three adsorbent–adsorbate pairs, namely, Maxsorb III–ethanol, Maxsorb III–R507a, and Maxsorb III–R134a. Based on the mathematical investigations, it is observed that the cooling capacity can be improved significantly at a litter higher cost of the heat transfer mechanism.

Monitoring and simulation of parabolic trough collector powered vapor absorption refrigeration system for rural cold storage

India is one of the largest contributors to the world?s agricultural products. The majority of people?s livelihood in India depends on agriculture and its allied sectors. According to an economics survey in the agricultural year of 2019-2020, India is estimated to have produced around 292 million tonnes of food grain. The share of agriculture in India?s GDP is 19.9%. Even though India is an active participant in global agricultural trade, the total agricultural product export is only 2.5%. Agricultural produce is easily perishable and the quality gets affected which will then affect their market value. To meet the future food demands, agricultural produce must be able to store for a longer amount of time for round the year availability. The traditional food storage practices cannot satisfy that condition. These perishables need a proper cold supply chain to increase the shelf life. In this paper performance of a Parabolic Trough Collector Integrated Vapor Absorption Refrigeration system was developed and studied. Renewable integrated cold storage would open door to the sustainable energy future.