Numerical simulation of cascaded absorption-two-stage 4-bed adsorption cooling cycles for efficient low-grade heat utilization

Abstract

Thermal-driven sorption cooling technology was developed to address some pressing challenges including high energy consumption, rising fuel prices, and environmental issues associated with traditional electrical-driven cycles. Nevertheless, this technology needs to be improved in terms of thermal performance and energy efficiency. This study investigates the performance of new cascade single-effect absorption (ABC) and two-stage four-bed adsorption (4ADC) cooling systems powered by low-grade heat source temperatures. Four different configurations are proposed to make proper use of low-temperature heat sources between 45 and 70 °C and improve heat recovery. The use of this temperature range to drive conventional ABC is still considerably lacking in the literature. The ABC does not typically operate below 60 °C. Additionally, the effects of operating conditions on performance are also investigated. The simulation models for both ABC and 4ADC systems are experimentally validated separately and showed excellent agreement. Results showed that the maximum cooling capacity obtained from the proposed system ranges between (5.4–17.1) kW with COP of 0.46–0.47. The COP is found to be relatively insensitive to regeneration temperatures. Increasing the solution pump flow rate increases the system performance by about 25% over the ranges of the regeneration temperature. The proposed configurations provide high energy performance compared with previous related studies. The obtained results proved that the proposed cascade configurations can recover the available low-grade heat source and operate effectively with temperatures between 45 and 70 °C.