SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin
Vol. 19 No. 2 (2025): SINTEK JURNAL

Energy Recovery from Split-Type Air Conditioners: Experimental Analysis of Integrated Water Heating Systems with Different Refrigerants

Haolia Rahman (Manufacturing Engineering Technology, Politeknik Negeri Jakarta, Depok 16425, Indonesia)
Paulus Sukusno (Department of Mechanical Engineering, Politeknik Negeri Jakarta, Depok 16425, Indonesia)
Ainun Nidhar (Department of Mechanical Engineering, Politeknik Negeri Jakarta, Depok 16425, Indonesia)



Article Info

Publish Date
01 Dec 2025

Abstract

Air conditioning (AC) systems use the evaporator to absorb heat from the indoor air to provide cooling. By utilizing the condenser side, these systems can also operate as heat pumps for water heating. However, such applications remain limited in Indonesia. This study experimentally investigates a modified split-type AC unit retrofitted with a 40 L insulated hot-water tank and a 10 m long, 5/8" diameter spiral copper tube condenser. Experiments were conducted over 180 minutes using R-22 and hydrocarbon (HC-290) refrigerants, with parameters recorded at 10-minute intervals. Results indicate that the modified system can simultaneously provide cooling and water heating with significant energy recovery. Using R-22, the system achieved electricity savings of 5.014 kWh/day (53.3%) with a payback period of 10.0 months. The HC refrigerant yielded savings of 4.384 kWh/day (47.8%) with an 11.4-month payback period. The measured cooling and heating coefficients of performance (COP) were 3.89 and 4.89, respectively. Unlike prior studies focused on theoretical aspects, this work provides experimental validation under realistic household conditions and includes an economic feasibility assessment. Study limitations include the absence of detailed uncertainty analysis and the assumption of constant hot-water demand. Future work should address measurement accuracy, dynamic load variations, and long-term system performance.

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Journal Info

Abbrev

sintek

Publisher

Subject

Automotive Engineering Control & Systems Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

Description

SINTEK JURNAL: Jurnal Ilmiah Teknik Mesin is an open access, peer-review journal which publishes original and review articles that advance the understanding of both the fundamentals of engineering science and its application to the solution of challenges and problems in mechanical engineering ...