Thermal performance of a dual-purpose collector-cum-storage type air-water heater

• Published in: Applied thermal engineering 2020-05, Vol.171, p.115094, Article 115094
• Main Authors: Somwanshi, Aneesh, Sarkar, Niladri
• Format: Article
• Language: English
• Subjects: Air flow; Air heating; Air temperature; Climate change; Collector-cum-storage device; Dual heater; Heat conductivity; Heat transfer; Mass flow rate; Solar energy; Thermodynamic efficiency; Water heaters; Water heating
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2020.115094

•The novel design of a dual-purpose collector cum storage type air–water heater has been developed.•The proposed collector can deliver hot water and air simultaneously.•The maximum thermal efficiency reached during day time is 82.4%•By covering the collector by insulating cover during night about 19.9% of heat energy can be saved.•The maximum water and air temperature reached is 89.6 °C and 81.1 °C during summer. The aim of this study is to design and develop a dual-purpose integrated solar collector-storage device that can simultaneously provide hot water and hot air. The device can be used as a single purpose air or water heater, based on the requirement. A Simple mathematical model of the proposed dual-purpose heater is presented and validated for the climate of Raipur, Chhattisgarh, India (21.25oN, 81.62oE). The performance of the collector is numerically computed for the composite climate of Delhi, India (28.70oN, 77.10oE). The results reveal that about 19.9% of the heat energy can be conserved by covering the collector with an insulating cover at night. The dual collector performs well when a low mass flow rate of air flows through the upper compartment, in comparison to high mass flow rate. The maximum thermal efficiency during day time is about 82.8% at a mass flow rate of 0.020 kg/s. Thermal efficiency of the proposed dual-purpose heater is higher than that of conventional single purpose water heater. The maximum water and air temperatures in December (winter) where 56 °C and 50 °C, respectively, whereas those for May (summer) where 89.6 °C and 81.1 °C, respectively.