Field Test and Analysis of Energy-Saving Effects of Energy-Recovery Ventilators on Heat-Pump Electricity Consumption in a Classroom

• Main Authors: Jae-Sol Choi, Eui-Jong Kim
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Sustainability
• Subjects: field measurement; energy consumption; energy-recovery ventilator (ERV); electric heat pump (EHP); calibration method; energy-saving effects
• Online Access: https://www.mdpi.com/2071-1050/11/7/2069

Energy-recovery ventilators (ERVs) are regarded as important energy-saving systems in buildings. It has been reported that they have high energy-saving rates compared with conventional ventilators that operate without energy recovery, but the saving rates have been obtained typically by employing chamber tests and simulations. In this work, a field-test method is proposed that uses a single test room but alternates the tested ventilation modes hourly. This proposed method is useful because an additional comparison room is not always available and can be a source of uncertainty for field tests. The test is performed in a classroom during a heating period, and the results are calibrated to account for different experimental conditions during the test period. The calibrated energy-saving rates indicate the effectiveness of the ERV; however, they are lower in the early hours of the system operation, for two reasons: (1) the maximum power control schemes of the heat pumps are applied for cases where the indoor temperatures are far lower than the set-point temperature; (2) the ventilation load seemingly represents a decreasing proportion of the total heating load in early hours owing to the thermal-capacity effects for the building, which was cooled for many hours. The findings are verified via a chamber test and simulations. As a consequence, it is important to account for actual system characteristics affected by the thermal behaviors of classrooms when the overall performance of a system is evaluated.