M. Yamaguchi et al., HEAT STORAGE-TYPE FLOOR HEATING-SYSTEM WI TH HEAT-PUMP DRIVEN BY DISCOUNT ELECTRICITY SUPPLIED AT NIGHT, Kagaku kogaku ronbunshu, 21(5), 1995, pp. 853-858
Heat storage-type floor heating by hot water from a heat pump driven 8
hrs by night electricity was studied. The phase change material (PCM)
used for heat storage was Na2SO4 . 10H(2)O package. Properties of the
PCM are; melting point 32 degrees C, solidification point 30 degrees
C, heat storage 43.0 W . h/kg (Delta T=10 degrees C). The floor heatin
g room was a 40 m(2), and without window, Na2SO4 . 10H(2)O package was
used as a phase change material for heat storage. Hot water panels la
id under PCM packages (26 m(2)) were placed on a stage 1.2 m above the
floor. The total heat storage was 28.5 kW. The heat pump was operated
in an 8 hrs ON-16 hrs OFF cycle so that three times the heat extracti
on was needed as compared with continuous operation. For this reason,
a Net film type vertical tube with a CFC flashing pump at the bottom w
as developed. From experimental results, the thermal balance of the sy
stem was calculated and the applicability for practical use was discus
sed.