Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank
Variable refrigerant flow (VRF) systems are common air-conditioning systems used in regions with moderate climates that have cooling and heating demands. Unlike typical air-source VRF systems, ground-source VRF systems require heat-source water circulation, and reducing the pumping power remains a s...
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MDPI AG
2024-11-01
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| Online Access: | https://www.mdpi.com/1996-1073/17/22/5564 |
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| author | Toya Tanaka Sayaka Kindaichi Keita Kawasaki Daisaku Nishina |
| author_facet | Toya Tanaka Sayaka Kindaichi Keita Kawasaki Daisaku Nishina |
| author_sort | Toya Tanaka |
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| description | Variable refrigerant flow (VRF) systems are common air-conditioning systems used in regions with moderate climates that have cooling and heating demands. Unlike typical air-source VRF systems, ground-source VRF systems require heat-source water circulation, and reducing the pumping power remains a significant problem. Herein, the intermittent pump control for circulating heat source water was achieved by installing a buffer water tank between the ground heat exchangers and VRF units. An intermittent control methodology was developed based on the indices of water transport efficiency and incorporated into a system simulation model with 72 boreholes, a cooling capacity of 252 kW, and a buffer water tank of 30 m<sup>3</sup>. Results indicated that intermittent control was achieved at heat load ratios lower than 40% as expected. This intermittent control allowed more efficient water transport with 38% lower pumping power than conventional inverter controls. Although the proposed system equipped more pumps and heat exchangers than conventional systems, it exhibited higher energy efficiencies for most measurement days than the conventional air-conditioning systems. The annual energy consumption was thus reduced by 34% and 8% compared to air-source VRF systems and conventional ground-source VRF systems, respectively. |
| format | Article |
| id | doaj-art-44eb0297bdb34d14afa5aa3fd6dba026 |
| institution | OA Journals |
| issn | 1996-1073 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | MDPI AG |
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| series | Energies |
| spelling | doaj-art-44eb0297bdb34d14afa5aa3fd6dba0262025-08-20T01:53:45ZengMDPI AGEnergies1996-10732024-11-011722556410.3390/en17225564Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water TankToya Tanaka0Sayaka Kindaichi1Keita Kawasaki2Daisaku Nishina3Department of Civil Engineering and Architecture, Shikoku Electric Power Co., Inc., Takamatsu 760-8573, JapanGraduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima 739-8527, JapanDepartment of Architecture and Structural Engineering, National Institute of Technology (KOSEN), Kure College, Kure 737-8506, JapanGraduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima 739-8527, JapanVariable refrigerant flow (VRF) systems are common air-conditioning systems used in regions with moderate climates that have cooling and heating demands. Unlike typical air-source VRF systems, ground-source VRF systems require heat-source water circulation, and reducing the pumping power remains a significant problem. Herein, the intermittent pump control for circulating heat source water was achieved by installing a buffer water tank between the ground heat exchangers and VRF units. An intermittent control methodology was developed based on the indices of water transport efficiency and incorporated into a system simulation model with 72 boreholes, a cooling capacity of 252 kW, and a buffer water tank of 30 m<sup>3</sup>. Results indicated that intermittent control was achieved at heat load ratios lower than 40% as expected. This intermittent control allowed more efficient water transport with 38% lower pumping power than conventional inverter controls. Although the proposed system equipped more pumps and heat exchangers than conventional systems, it exhibited higher energy efficiencies for most measurement days than the conventional air-conditioning systems. The annual energy consumption was thus reduced by 34% and 8% compared to air-source VRF systems and conventional ground-source VRF systems, respectively.https://www.mdpi.com/1996-1073/17/22/5564ground-source variable refrigerant flow systemsbuffer water tankintermittent controlwater transportation factorenergy consumption |
| spellingShingle | Toya Tanaka Sayaka Kindaichi Keita Kawasaki Daisaku Nishina Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank Energies ground-source variable refrigerant flow systems buffer water tank intermittent control water transportation factor energy consumption |
| title | Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank |
| title_full | Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank |
| title_fullStr | Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank |
| title_full_unstemmed | Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank |
| title_short | Energy-Saving Effects of the Intermittent Control of Pumps in Ground Source Variable Refrigerant Flow Systems with a Buffer Water Tank |
| title_sort | energy saving effects of the intermittent control of pumps in ground source variable refrigerant flow systems with a buffer water tank |
| topic | ground-source variable refrigerant flow systems buffer water tank intermittent control water transportation factor energy consumption |
| url | https://www.mdpi.com/1996-1073/17/22/5564 |
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