Heat storage-type floor heating system with heat pump driven by nighttime electric power

✍ Scribed by Yamaguchi, Munehiro ;Sayama, Sogo ;Yoneda, Hirokazu ;Iwamoto, Kin-ya ;Harada, Mitsuhiro ;Watanabe, Satoru ;Fukai, Kazuo

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 136 KB
• Volume: 26
• Category: Article
• ISSN: 0096-0802
• DOI: 10.1002/(sici)1520-6556(1997)26:2<122::aid-htj6>3.0.co;2-y

✦ Synopsis

We performed tests for heat storage-type floor heating that employs a heat pump driven with nighttime electric power for 8 h (11 PM to 7 AM) as the heat source. The phase change material (PCM) applied was a package of mirabilite (Na2SO4 ⋅ 10H2O). The melting point is 32 °C, the freezing point 30 °C, and the stored heat amount 43 W ⋅ h/kg (∆T = 10 °C). The test room for floor heating was a wooden structure without windows and the floor area was 40 m 2 . The hot water panel (5 mm in thickness, made of plastic, 26 m 2 ) was laid on the stage (1.2 m in height) inside the room and the PCM was superimposed on the upper surface of the stage (the total stored heat amount was 28.5 kW).

Since the heat pump runs in cycles of 8-h operation and 16-h nonoperation, it needs an extracted heat amount of three times compared with the case of round-theclock operation. For this reason, we have developed a wet film-type vertical heat extracting tube with a built-in Freon flashing pump, to obtain extracted heat about three times greater than was previously possible. We have calculated the heat balance from the results of the tests for floor heating and have studied the practicability of this system.