| Issue |
E3S Web of Conf.
Volume 396, 2023
The 11th International Conference on Indoor Air Quality, Ventilation & Energy Conservation in Buildings (IAQVEC2023)
|
|
|---|---|---|
| Article Number | 03010 | |
| Number of page(s) | 5 | |
| Section | Energy Efficient and Healthy HVAC systems | |
| DOI | https://doi.org/10.1051/e3sconf/202339603010 | |
| Published online | 16 June 2023 | |
Reducing energy consumption of heat pumps by introducing a thermal energy storage system
Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan.
* Corresponding author: kindaichi@hiroshima-u.ac.jp
We proposed a short-term thermal energy storage system by applying Phase Change Materials (PCMs) in air ducts connected to an indoor air conditioning unit within a ceiling space. PCM tubes were arranged in a staggered layout in the air duct and cooled by chilled air from the air conditioning unit during “charging” mode, whereas the PCM tubes released cold energy to the room space without operation of the compressor during “discharging” mode. The charging mode allowed for an increase in the partial load ratio of the heat pump to prevent low-efficiency operation at <20% load, which can increase seasonal energy efficiency. We constructed an energy simulation program, where the heat exchange coefficient between the PCM tubes and air was varied with airflow rate and the temperature difference between the PCM and air, in accordance with results from CFD analysis. Switching between the charging and discharging modes was based on the outlet temperature (Tout) and 30% of the rated capacity of the indoor unit (Lr). The heat balance between the charging and discharging modes was improved by this change to the system control. A higher load factor and higher COP resulted in a 7.6% reduction in energy consumption.
© The Authors, published by EDP Sciences, 2023
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